diff options
Diffstat (limited to 'target/arm/tcg/m_helper.c')
| -rw-r--r-- | target/arm/tcg/m_helper.c | 2902 |
1 files changed, 2902 insertions, 0 deletions
diff --git a/target/arm/tcg/m_helper.c b/target/arm/tcg/m_helper.c new file mode 100644 index 0000000000..f94e87e728 --- /dev/null +++ b/target/arm/tcg/m_helper.c @@ -0,0 +1,2902 @@ +/* + * ARM generic helpers. + * + * This code is licensed under the GNU GPL v2 or later. + * + * SPDX-License-Identifier: GPL-2.0-or-later + */ + +#include "qemu/osdep.h" +#include "cpu.h" +#include "internals.h" +#include "exec/helper-proto.h" +#include "qemu/main-loop.h" +#include "qemu/bitops.h" +#include "qemu/log.h" +#include "exec/exec-all.h" +#ifdef CONFIG_TCG +#include "exec/cpu_ldst.h" +#include "semihosting/common-semi.h" +#endif +#if !defined(CONFIG_USER_ONLY) +#include "hw/intc/armv7m_nvic.h" +#endif + +static void v7m_msr_xpsr(CPUARMState *env, uint32_t mask, + uint32_t reg, uint32_t val) +{ + /* Only APSR is actually writable */ + if (!(reg & 4)) { + uint32_t apsrmask = 0; + + if (mask & 8) { + apsrmask |= XPSR_NZCV | XPSR_Q; + } + if ((mask & 4) && arm_feature(env, ARM_FEATURE_THUMB_DSP)) { + apsrmask |= XPSR_GE; + } + xpsr_write(env, val, apsrmask); + } +} + +static uint32_t v7m_mrs_xpsr(CPUARMState *env, uint32_t reg, unsigned el) +{ + uint32_t mask = 0; + + if ((reg & 1) && el) { + mask |= XPSR_EXCP; /* IPSR (unpriv. reads as zero) */ + } + if (!(reg & 4)) { + mask |= XPSR_NZCV | XPSR_Q; /* APSR */ + if (arm_feature(env, ARM_FEATURE_THUMB_DSP)) { + mask |= XPSR_GE; + } + } + /* EPSR reads as zero */ + return xpsr_read(env) & mask; +} + +static uint32_t v7m_mrs_control(CPUARMState *env, uint32_t secure) +{ + uint32_t value = env->v7m.control[secure]; + + if (!secure) { + /* SFPA is RAZ/WI from NS; FPCA is stored in the M_REG_S bank */ + value |= env->v7m.control[M_REG_S] & R_V7M_CONTROL_FPCA_MASK; + } + return value; +} + +#ifdef CONFIG_USER_ONLY + +void HELPER(v7m_msr)(CPUARMState *env, uint32_t maskreg, uint32_t val) +{ + uint32_t mask = extract32(maskreg, 8, 4); + uint32_t reg = extract32(maskreg, 0, 8); + + switch (reg) { + case 0 ... 7: /* xPSR sub-fields */ + v7m_msr_xpsr(env, mask, reg, val); + break; + case 20: /* CONTROL */ + /* There are no sub-fields that are actually writable from EL0. */ + break; + default: + /* Unprivileged writes to other registers are ignored */ + break; + } +} + +uint32_t HELPER(v7m_mrs)(CPUARMState *env, uint32_t reg) +{ + switch (reg) { + case 0 ... 7: /* xPSR sub-fields */ + return v7m_mrs_xpsr(env, reg, 0); + case 20: /* CONTROL */ + return v7m_mrs_control(env, 0); + default: + /* Unprivileged reads others as zero. */ + return 0; + } +} + +void HELPER(v7m_bxns)(CPUARMState *env, uint32_t dest) +{ + /* translate.c should never generate calls here in user-only mode */ + g_assert_not_reached(); +} + +void HELPER(v7m_blxns)(CPUARMState *env, uint32_t dest) +{ + /* translate.c should never generate calls here in user-only mode */ + g_assert_not_reached(); +} + +void HELPER(v7m_preserve_fp_state)(CPUARMState *env) +{ + /* translate.c should never generate calls here in user-only mode */ + g_assert_not_reached(); +} + +void HELPER(v7m_vlstm)(CPUARMState *env, uint32_t fptr) +{ + /* translate.c should never generate calls here in user-only mode */ + g_assert_not_reached(); +} + +void HELPER(v7m_vlldm)(CPUARMState *env, uint32_t fptr) +{ + /* translate.c should never generate calls here in user-only mode */ + g_assert_not_reached(); +} + +uint32_t HELPER(v7m_tt)(CPUARMState *env, uint32_t addr, uint32_t op) +{ + /* + * The TT instructions can be used by unprivileged code, but in + * user-only emulation we don't have the MPU. + * Luckily since we know we are NonSecure unprivileged (and that in + * turn means that the A flag wasn't specified), all the bits in the + * register must be zero: + * IREGION: 0 because IRVALID is 0 + * IRVALID: 0 because NS + * S: 0 because NS + * NSRW: 0 because NS + * NSR: 0 because NS + * RW: 0 because unpriv and A flag not set + * R: 0 because unpriv and A flag not set + * SRVALID: 0 because NS + * MRVALID: 0 because unpriv and A flag not set + * SREGION: 0 becaus SRVALID is 0 + * MREGION: 0 because MRVALID is 0 + */ + return 0; +} + +ARMMMUIdx arm_v7m_mmu_idx_for_secstate(CPUARMState *env, bool secstate) +{ + return ARMMMUIdx_MUser; +} + +#else /* !CONFIG_USER_ONLY */ + +static ARMMMUIdx arm_v7m_mmu_idx_all(CPUARMState *env, + bool secstate, bool priv, bool negpri) +{ + ARMMMUIdx mmu_idx = ARM_MMU_IDX_M; + + if (priv) { + mmu_idx |= ARM_MMU_IDX_M_PRIV; + } + + if (negpri) { + mmu_idx |= ARM_MMU_IDX_M_NEGPRI; + } + + if (secstate) { + mmu_idx |= ARM_MMU_IDX_M_S; + } + + return mmu_idx; +} + +static ARMMMUIdx arm_v7m_mmu_idx_for_secstate_and_priv(CPUARMState *env, + bool secstate, bool priv) +{ + bool negpri = armv7m_nvic_neg_prio_requested(env->nvic, secstate); + + return arm_v7m_mmu_idx_all(env, secstate, priv, negpri); +} + +/* Return the MMU index for a v7M CPU in the specified security state */ +ARMMMUIdx arm_v7m_mmu_idx_for_secstate(CPUARMState *env, bool secstate) +{ + bool priv = arm_v7m_is_handler_mode(env) || + !(env->v7m.control[secstate] & 1); + + return arm_v7m_mmu_idx_for_secstate_and_priv(env, secstate, priv); +} + +/* + * What kind of stack write are we doing? This affects how exceptions + * generated during the stacking are treated. + */ +typedef enum StackingMode { + STACK_NORMAL, + STACK_IGNFAULTS, + STACK_LAZYFP, +} StackingMode; + +static bool v7m_stack_write(ARMCPU *cpu, uint32_t addr, uint32_t value, + ARMMMUIdx mmu_idx, StackingMode mode) +{ + CPUState *cs = CPU(cpu); + CPUARMState *env = &cpu->env; + MemTxResult txres; + GetPhysAddrResult res = {}; + ARMMMUFaultInfo fi = {}; + bool secure = mmu_idx & ARM_MMU_IDX_M_S; + int exc; + bool exc_secure; + + if (get_phys_addr(env, addr, MMU_DATA_STORE, mmu_idx, &res, &fi)) { + /* MPU/SAU lookup failed */ + if (fi.type == ARMFault_QEMU_SFault) { + if (mode == STACK_LAZYFP) { + qemu_log_mask(CPU_LOG_INT, + "...SecureFault with SFSR.LSPERR " + "during lazy stacking\n"); + env->v7m.sfsr |= R_V7M_SFSR_LSPERR_MASK; + } else { + qemu_log_mask(CPU_LOG_INT, + "...SecureFault with SFSR.AUVIOL " + "during stacking\n"); + env->v7m.sfsr |= R_V7M_SFSR_AUVIOL_MASK; + } + env->v7m.sfsr |= R_V7M_SFSR_SFARVALID_MASK; + env->v7m.sfar = addr; + exc = ARMV7M_EXCP_SECURE; + exc_secure = false; + } else { + if (mode == STACK_LAZYFP) { + qemu_log_mask(CPU_LOG_INT, + "...MemManageFault with CFSR.MLSPERR\n"); + env->v7m.cfsr[secure] |= R_V7M_CFSR_MLSPERR_MASK; + } else { + qemu_log_mask(CPU_LOG_INT, + "...MemManageFault with CFSR.MSTKERR\n"); + env->v7m.cfsr[secure] |= R_V7M_CFSR_MSTKERR_MASK; + } + exc = ARMV7M_EXCP_MEM; + exc_secure = secure; + } + goto pend_fault; + } + address_space_stl_le(arm_addressspace(cs, res.f.attrs), res.f.phys_addr, + value, res.f.attrs, &txres); + if (txres != MEMTX_OK) { + /* BusFault trying to write the data */ + if (mode == STACK_LAZYFP) { + qemu_log_mask(CPU_LOG_INT, "...BusFault with BFSR.LSPERR\n"); + env->v7m.cfsr[M_REG_NS] |= R_V7M_CFSR_LSPERR_MASK; + } else { + qemu_log_mask(CPU_LOG_INT, "...BusFault with BFSR.STKERR\n"); + env->v7m.cfsr[M_REG_NS] |= R_V7M_CFSR_STKERR_MASK; + } + exc = ARMV7M_EXCP_BUS; + exc_secure = false; + goto pend_fault; + } + return true; + +pend_fault: + /* + * By pending the exception at this point we are making + * the IMPDEF choice "overridden exceptions pended" (see the + * MergeExcInfo() pseudocode). The other choice would be to not + * pend them now and then make a choice about which to throw away + * later if we have two derived exceptions. + * The only case when we must not pend the exception but instead + * throw it away is if we are doing the push of the callee registers + * and we've already generated a derived exception (this is indicated + * by the caller passing STACK_IGNFAULTS). Even in this case we will + * still update the fault status registers. + */ + switch (mode) { + case STACK_NORMAL: + armv7m_nvic_set_pending_derived(env->nvic, exc, exc_secure); + break; + case STACK_LAZYFP: + armv7m_nvic_set_pending_lazyfp(env->nvic, exc, exc_secure); + break; + case STACK_IGNFAULTS: + break; + } + return false; +} + +static bool v7m_stack_read(ARMCPU *cpu, uint32_t *dest, uint32_t addr, + ARMMMUIdx mmu_idx) +{ + CPUState *cs = CPU(cpu); + CPUARMState *env = &cpu->env; + MemTxResult txres; + GetPhysAddrResult res = {}; + ARMMMUFaultInfo fi = {}; + bool secure = mmu_idx & ARM_MMU_IDX_M_S; + int exc; + bool exc_secure; + uint32_t value; + + if (get_phys_addr(env, addr, MMU_DATA_LOAD, mmu_idx, &res, &fi)) { + /* MPU/SAU lookup failed */ + if (fi.type == ARMFault_QEMU_SFault) { + qemu_log_mask(CPU_LOG_INT, + "...SecureFault with SFSR.AUVIOL during unstack\n"); + env->v7m.sfsr |= R_V7M_SFSR_AUVIOL_MASK | R_V7M_SFSR_SFARVALID_MASK; + env->v7m.sfar = addr; + exc = ARMV7M_EXCP_SECURE; + exc_secure = false; + } else { + qemu_log_mask(CPU_LOG_INT, + "...MemManageFault with CFSR.MUNSTKERR\n"); + env->v7m.cfsr[secure] |= R_V7M_CFSR_MUNSTKERR_MASK; + exc = ARMV7M_EXCP_MEM; + exc_secure = secure; + } + goto pend_fault; + } + + value = address_space_ldl(arm_addressspace(cs, res.f.attrs), + res.f.phys_addr, res.f.attrs, &txres); + if (txres != MEMTX_OK) { + /* BusFault trying to read the data */ + qemu_log_mask(CPU_LOG_INT, "...BusFault with BFSR.UNSTKERR\n"); + env->v7m.cfsr[M_REG_NS] |= R_V7M_CFSR_UNSTKERR_MASK; + exc = ARMV7M_EXCP_BUS; + exc_secure = false; + goto pend_fault; + } + + *dest = value; + return true; + +pend_fault: + /* + * By pending the exception at this point we are making + * the IMPDEF choice "overridden exceptions pended" (see the + * MergeExcInfo() pseudocode). The other choice would be to not + * pend them now and then make a choice about which to throw away + * later if we have two derived exceptions. + */ + armv7m_nvic_set_pending(env->nvic, exc, exc_secure); + return false; +} + +void HELPER(v7m_preserve_fp_state)(CPUARMState *env) +{ + /* + * Preserve FP state (because LSPACT was set and we are about + * to execute an FP instruction). This corresponds to the + * PreserveFPState() pseudocode. + * We may throw an exception if the stacking fails. + */ + ARMCPU *cpu = env_archcpu(env); + bool is_secure = env->v7m.fpccr[M_REG_S] & R_V7M_FPCCR_S_MASK; + bool negpri = !(env->v7m.fpccr[M_REG_S] & R_V7M_FPCCR_HFRDY_MASK); + bool is_priv = !(env->v7m.fpccr[is_secure] & R_V7M_FPCCR_USER_MASK); + bool splimviol = env->v7m.fpccr[is_secure] & R_V7M_FPCCR_SPLIMVIOL_MASK; + uint32_t fpcar = env->v7m.fpcar[is_secure]; + bool stacked_ok = true; + bool ts = is_secure && (env->v7m.fpccr[M_REG_S] & R_V7M_FPCCR_TS_MASK); + bool take_exception; + + /* Take the iothread lock as we are going to touch the NVIC */ + qemu_mutex_lock_iothread(); + + /* Check the background context had access to the FPU */ + if (!v7m_cpacr_pass(env, is_secure, is_priv)) { + armv7m_nvic_set_pending_lazyfp(env->nvic, ARMV7M_EXCP_USAGE, is_secure); + env->v7m.cfsr[is_secure] |= R_V7M_CFSR_NOCP_MASK; + stacked_ok = false; + } else if (!is_secure && !extract32(env->v7m.nsacr, 10, 1)) { + armv7m_nvic_set_pending_lazyfp(env->nvic, ARMV7M_EXCP_USAGE, M_REG_S); + env->v7m.cfsr[M_REG_S] |= R_V7M_CFSR_NOCP_MASK; + stacked_ok = false; + } + + if (!splimviol && stacked_ok) { + /* We only stack if the stack limit wasn't violated */ + int i; + ARMMMUIdx mmu_idx; + + mmu_idx = arm_v7m_mmu_idx_all(env, is_secure, is_priv, negpri); + for (i = 0; i < (ts ? 32 : 16); i += 2) { + uint64_t dn = *aa32_vfp_dreg(env, i / 2); + uint32_t faddr = fpcar + 4 * i; + uint32_t slo = extract64(dn, 0, 32); + uint32_t shi = extract64(dn, 32, 32); + + if (i >= 16) { + faddr += 8; /* skip the slot for the FPSCR/VPR */ + } + stacked_ok = stacked_ok && + v7m_stack_write(cpu, faddr, slo, mmu_idx, STACK_LAZYFP) && + v7m_stack_write(cpu, faddr + 4, shi, mmu_idx, STACK_LAZYFP); + } + + stacked_ok = stacked_ok && + v7m_stack_write(cpu, fpcar + 0x40, + vfp_get_fpscr(env), mmu_idx, STACK_LAZYFP); + if (cpu_isar_feature(aa32_mve, cpu)) { + stacked_ok = stacked_ok && + v7m_stack_write(cpu, fpcar + 0x44, + env->v7m.vpr, mmu_idx, STACK_LAZYFP); + } + } + + /* + * We definitely pended an exception, but it's possible that it + * might not be able to be taken now. If its priority permits us + * to take it now, then we must not update the LSPACT or FP regs, + * but instead jump out to take the exception immediately. + * If it's just pending and won't be taken until the current + * handler exits, then we do update LSPACT and the FP regs. + */ + take_exception = !stacked_ok && + armv7m_nvic_can_take_pending_exception(env->nvic); + + qemu_mutex_unlock_iothread(); + + if (take_exception) { + raise_exception_ra(env, EXCP_LAZYFP, 0, 1, GETPC()); + } + + env->v7m.fpccr[is_secure] &= ~R_V7M_FPCCR_LSPACT_MASK; + + if (ts) { + /* Clear s0 to s31 and the FPSCR and VPR */ + int i; + + for (i = 0; i < 32; i += 2) { + *aa32_vfp_dreg(env, i / 2) = 0; + } + vfp_set_fpscr(env, 0); + if (cpu_isar_feature(aa32_mve, cpu)) { + env->v7m.vpr = 0; + } + } + /* + * Otherwise s0 to s15, FPSCR and VPR are UNKNOWN; we choose to leave them + * unchanged. + */ +} + +/* + * Write to v7M CONTROL.SPSEL bit for the specified security bank. + * This may change the current stack pointer between Main and Process + * stack pointers if it is done for the CONTROL register for the current + * security state. + */ +static void write_v7m_control_spsel_for_secstate(CPUARMState *env, + bool new_spsel, + bool secstate) +{ + bool old_is_psp = v7m_using_psp(env); + + env->v7m.control[secstate] = + deposit32(env->v7m.control[secstate], + R_V7M_CONTROL_SPSEL_SHIFT, + R_V7M_CONTROL_SPSEL_LENGTH, new_spsel); + + if (secstate == env->v7m.secure) { + bool new_is_psp = v7m_using_psp(env); + uint32_t tmp; + + if (old_is_psp != new_is_psp) { + tmp = env->v7m.other_sp; + env->v7m.other_sp = env->regs[13]; + env->regs[13] = tmp; + } + } +} + +/* + * Write to v7M CONTROL.SPSEL bit. This may change the current + * stack pointer between Main and Process stack pointers. + */ +static void write_v7m_control_spsel(CPUARMState *env, bool new_spsel) +{ + write_v7m_control_spsel_for_secstate(env, new_spsel, env->v7m.secure); +} + +void write_v7m_exception(CPUARMState *env, uint32_t new_exc) +{ + /* + * Write a new value to v7m.exception, thus transitioning into or out + * of Handler mode; this may result in a change of active stack pointer. + */ + bool new_is_psp, old_is_psp = v7m_using_psp(env); + uint32_t tmp; + + env->v7m.exception = new_exc; + + new_is_psp = v7m_using_psp(env); + + if (old_is_psp != new_is_psp) { + tmp = env->v7m.other_sp; + env->v7m.other_sp = env->regs[13]; + env->regs[13] = tmp; + } +} + +/* Switch M profile security state between NS and S */ +static void switch_v7m_security_state(CPUARMState *env, bool new_secstate) +{ + uint32_t new_ss_msp, new_ss_psp; + + if (env->v7m.secure == new_secstate) { + return; + } + + /* + * All the banked state is accessed by looking at env->v7m.secure + * except for the stack pointer; rearrange the SP appropriately. + */ + new_ss_msp = env->v7m.other_ss_msp; + new_ss_psp = env->v7m.other_ss_psp; + + if (v7m_using_psp(env)) { + env->v7m.other_ss_psp = env->regs[13]; + env->v7m.other_ss_msp = env->v7m.other_sp; + } else { + env->v7m.other_ss_msp = env->regs[13]; + env->v7m.other_ss_psp = env->v7m.other_sp; + } + + env->v7m.secure = new_secstate; + + if (v7m_using_psp(env)) { + env->regs[13] = new_ss_psp; + env->v7m.other_sp = new_ss_msp; + } else { + env->regs[13] = new_ss_msp; + env->v7m.other_sp = new_ss_psp; + } +} + +void HELPER(v7m_bxns)(CPUARMState *env, uint32_t dest) +{ + /* + * Handle v7M BXNS: + * - if the return value is a magic value, do exception return (like BX) + * - otherwise bit 0 of the return value is the target security state + */ + uint32_t min_magic; + + if (arm_feature(env, ARM_FEATURE_M_SECURITY)) { + /* Covers FNC_RETURN and EXC_RETURN magic */ + min_magic = FNC_RETURN_MIN_MAGIC; + } else { + /* EXC_RETURN magic only */ + min_magic = EXC_RETURN_MIN_MAGIC; + } + + if (dest >= min_magic) { + /* + * This is an exception return magic value; put it where + * do_v7m_exception_exit() expects and raise EXCEPTION_EXIT. + * Note that if we ever add gen_ss_advance() singlestep support to + * M profile this should count as an "instruction execution complete" + * event (compare gen_bx_excret_final_code()). + */ + env->regs[15] = dest & ~1; + env->thumb = dest & 1; + HELPER(exception_internal)(env, EXCP_EXCEPTION_EXIT); + /* notreached */ + } + + /* translate.c should have made BXNS UNDEF unless we're secure */ + assert(env->v7m.secure); + + if (!(dest & 1)) { + env->v7m.control[M_REG_S] &= ~R_V7M_CONTROL_SFPA_MASK; + } + switch_v7m_security_state(env, dest & 1); + env->thumb = true; + env->regs[15] = dest & ~1; + arm_rebuild_hflags(env); +} + +void HELPER(v7m_blxns)(CPUARMState *env, uint32_t dest) +{ + /* + * Handle v7M BLXNS: + * - bit 0 of the destination address is the target security state + */ + + /* At this point regs[15] is the address just after the BLXNS */ + uint32_t nextinst = env->regs[15] | 1; + uint32_t sp = env->regs[13] - 8; + uint32_t saved_psr; + + /* translate.c will have made BLXNS UNDEF unless we're secure */ + assert(env->v7m.secure); + + if (dest & 1) { + /* + * Target is Secure, so this is just a normal BLX, + * except that the low bit doesn't indicate Thumb/not. + */ + env->regs[14] = nextinst; + env->thumb = true; + env->regs[15] = dest & ~1; + return; + } + + /* Target is non-secure: first push a stack frame */ + if (!QEMU_IS_ALIGNED(sp, 8)) { + qemu_log_mask(LOG_GUEST_ERROR, + "BLXNS with misaligned SP is UNPREDICTABLE\n"); + } + + if (sp < v7m_sp_limit(env)) { + raise_exception(env, EXCP_STKOF, 0, 1); + } + + saved_psr = env->v7m.exception; + if (env->v7m.control[M_REG_S] & R_V7M_CONTROL_SFPA_MASK) { + saved_psr |= XPSR_SFPA; + } + + /* Note that these stores can throw exceptions on MPU faults */ + cpu_stl_data_ra(env, sp, nextinst, GETPC()); + cpu_stl_data_ra(env, sp + 4, saved_psr, GETPC()); + + env->regs[13] = sp; + env->regs[14] = 0xfeffffff; + if (arm_v7m_is_handler_mode(env)) { + /* + * Write a dummy value to IPSR, to avoid leaking the current secure + * exception number to non-secure code. This is guaranteed not + * to cause write_v7m_exception() to actually change stacks. + */ + write_v7m_exception(env, 1); + } + env->v7m.control[M_REG_S] &= ~R_V7M_CONTROL_SFPA_MASK; + switch_v7m_security_state(env, 0); + env->thumb = true; + env->regs[15] = dest; + arm_rebuild_hflags(env); +} + +static uint32_t *get_v7m_sp_ptr(CPUARMState *env, bool secure, bool threadmode, + bool spsel) +{ + /* + * Return a pointer to the location where we currently store the + * stack pointer for the requested security state and thread mode. + * This pointer will become invalid if the CPU state is updated + * such that the stack pointers are switched around (eg changing + * the SPSEL control bit). + * Compare the v8M ARM ARM pseudocode LookUpSP_with_security_mode(). + * Unlike that pseudocode, we require the caller to pass us in the + * SPSEL control bit value; this is because we also use this + * function in handling of pushing of the callee-saves registers + * part of the v8M stack frame (pseudocode PushCalleeStack()), + * and in the tailchain codepath the SPSEL bit comes from the exception + * return magic LR value from the previous exception. The pseudocode + * opencodes the stack-selection in PushCalleeStack(), but we prefer + * to make this utility function generic enough to do the job. + */ + bool want_psp = threadmode && spsel; + + if (secure == env->v7m.secure) { + if (want_psp == v7m_using_psp(env)) { + return &env->regs[13]; + } else { + return &env->v7m.other_sp; + } + } else { + if (want_psp) { + return &env->v7m.other_ss_psp; + } else { + return &env->v7m.other_ss_msp; + } + } +} + +static bool arm_v7m_load_vector(ARMCPU *cpu, int exc, bool targets_secure, + uint32_t *pvec) +{ + CPUState *cs = CPU(cpu); + CPUARMState *env = &cpu->env; + MemTxResult result; + uint32_t addr = env->v7m.vecbase[targets_secure] + exc * 4; + uint32_t vector_entry; + MemTxAttrs attrs = {}; + ARMMMUIdx mmu_idx; + bool exc_secure; + + qemu_log_mask(CPU_LOG_INT, + "...loading from element %d of %s vector table at 0x%x\n", + exc, targets_secure ? "secure" : "non-secure", addr); + + mmu_idx = arm_v7m_mmu_idx_for_secstate_and_priv(env, targets_secure, true); + + /* + * We don't do a get_phys_addr() here because the rules for vector + * loads are special: they always use the default memory map, and + * the default memory map permits reads from all addresses. + * Since there's no easy way to pass through to pmsav8_mpu_lookup() + * that we want this special case which would always say "yes", + * we just do the SAU lookup here followed by a direct physical load. + */ + attrs.secure = targets_secure; + attrs.user = false; + + if (arm_feature(env, ARM_FEATURE_M_SECURITY)) { + V8M_SAttributes sattrs = {}; + + v8m_security_lookup(env, addr, MMU_DATA_LOAD, mmu_idx, + targets_secure, &sattrs); + if (sattrs.ns) { + attrs.secure = false; + } else if (!targets_secure) { + /* + * NS access to S memory: the underlying exception which we escalate + * to HardFault is SecureFault, which always targets Secure. + */ + exc_secure = true; + goto load_fail; + } + } + + vector_entry = address_space_ldl(arm_addressspace(cs, attrs), addr, + attrs, &result); + if (result != MEMTX_OK) { + /* + * Underlying exception is BusFault: its target security state + * depends on BFHFNMINS. + */ + exc_secure = !(cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK); + goto load_fail; + } + *pvec = vector_entry; + qemu_log_mask(CPU_LOG_INT, "...loaded new PC 0x%x\n", *pvec); + return true; + +load_fail: + /* + * All vector table fetch fails are reported as HardFault, with + * HFSR.VECTTBL and .FORCED set. (FORCED is set because + * technically the underlying exception is a SecureFault or BusFault + * that is escalated to HardFault.) This is a terminal exception, + * so we will either take the HardFault immediately or else enter + * lockup (the latter case is handled in armv7m_nvic_set_pending_derived()). + * The HardFault is Secure if BFHFNMINS is 0 (meaning that all HFs are + * secure); otherwise it targets the same security state as the + * underlying exception. + * In v8.1M HardFaults from vector table fetch fails don't set FORCED. + */ + if (!(cpu->env.v7m.aircr & R_V7M_AIRCR_BFHFNMINS_MASK)) { + exc_secure = true; + } + env->v7m.hfsr |= R_V7M_HFSR_VECTTBL_MASK; + if (!arm_feature(env, ARM_FEATURE_V8_1M)) { + env->v7m.hfsr |= R_V7M_HFSR_FORCED_MASK; + } + armv7m_nvic_set_pending_derived(env->nvic, ARMV7M_EXCP_HARD, exc_secure); + return false; +} + +static uint32_t v7m_integrity_sig(CPUARMState *env, uint32_t lr) +{ + /* + * Return the integrity signature value for the callee-saves + * stack frame section. @lr is the exception return payload/LR value + * whose FType bit forms bit 0 of the signature if FP is present. + */ + uint32_t sig = 0xfefa125a; + + if (!cpu_isar_feature(aa32_vfp_simd, env_archcpu(env)) + || (lr & R_V7M_EXCRET_FTYPE_MASK)) { + sig |= 1; + } + return sig; +} + +static bool v7m_push_callee_stack(ARMCPU *cpu, uint32_t lr, bool dotailchain, + bool ignore_faults) +{ + /* + * For v8M, push the callee-saves register part of the stack frame. + * Compare the v8M pseudocode PushCalleeStack(). + * In the tailchaining case this may not be the current stack. + */ + CPUARMState *env = &cpu->env; + uint32_t *frame_sp_p; + uint32_t frameptr; + ARMMMUIdx mmu_idx; + bool stacked_ok; + uint32_t limit; + bool want_psp; + uint32_t sig; + StackingMode smode = ignore_faults ? STACK_IGNFAULTS : STACK_NORMAL; + + if (dotailchain) { + bool mode = lr & R_V7M_EXCRET_MODE_MASK; + bool priv = !(env->v7m.control[M_REG_S] & R_V7M_CONTROL_NPRIV_MASK) || + !mode; + + mmu_idx = arm_v7m_mmu_idx_for_secstate_and_priv(env, M_REG_S, priv); + frame_sp_p = get_v7m_sp_ptr(env, M_REG_S, mode, + lr & R_V7M_EXCRET_SPSEL_MASK); + want_psp = mode && (lr & R_V7M_EXCRET_SPSEL_MASK); + if (want_psp) { + limit = env->v7m.psplim[M_REG_S]; + } else { + limit = env->v7m.msplim[M_REG_S]; + } + } else { + mmu_idx = arm_mmu_idx(env); + frame_sp_p = &env->regs[13]; + limit = v7m_sp_limit(env); + } + + frameptr = *frame_sp_p - 0x28; + if (frameptr < limit) { + /* + * Stack limit failure: set SP to the limit value, and generate + * STKOF UsageFault. Stack pushes below the limit must not be + * performed. It is IMPDEF whether pushes above the limit are + * performed; we choose not to. + */ + qemu_log_mask(CPU_LOG_INT, + "...STKOF during callee-saves register stacking\n"); + env->v7m.cfsr[env->v7m.secure] |= R_V7M_CFSR_STKOF_MASK; + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE, + env->v7m.secure); + *frame_sp_p = limit; + return true; + } + + /* + * Write as much of the stack frame as we can. A write failure may + * cause us to pend a derived exception. + */ + sig = v7m_integrity_sig(env, lr); + stacked_ok = + v7m_stack_write(cpu, frameptr, sig, mmu_idx, smode) && + v7m_stack_write(cpu, frameptr + 0x8, env->regs[4], mmu_idx, smode) && + v7m_stack_write(cpu, frameptr + 0xc, env->regs[5], mmu_idx, smode) && + v7m_stack_write(cpu, frameptr + 0x10, env->regs[6], mmu_idx, smode) && + v7m_stack_write(cpu, frameptr + 0x14, env->regs[7], mmu_idx, smode) && + v7m_stack_write(cpu, frameptr + 0x18, env->regs[8], mmu_idx, smode) && + v7m_stack_write(cpu, frameptr + 0x1c, env->regs[9], mmu_idx, smode) && + v7m_stack_write(cpu, frameptr + 0x20, env->regs[10], mmu_idx, smode) && + v7m_stack_write(cpu, frameptr + 0x24, env->regs[11], mmu_idx, smode); + + /* Update SP regardless of whether any of the stack accesses failed. */ + *frame_sp_p = frameptr; + + return !stacked_ok; +} + +static void v7m_exception_taken(ARMCPU *cpu, uint32_t lr, bool dotailchain, + bool ignore_stackfaults) +{ + /* + * Do the "take the exception" parts of exception entry, + * but not the pushing of state to the stack. This is + * similar to the pseudocode ExceptionTaken() function. + */ + CPUARMState *env = &cpu->env; + uint32_t addr; + bool targets_secure; + int exc; + bool push_failed = false; + + armv7m_nvic_get_pending_irq_info(env->nvic, &exc, &targets_secure); + qemu_log_mask(CPU_LOG_INT, "...taking pending %s exception %d\n", + targets_secure ? "secure" : "nonsecure", exc); + + if (dotailchain) { + /* Sanitize LR FType and PREFIX bits */ + if (!cpu_isar_feature(aa32_vfp_simd, cpu)) { + lr |= R_V7M_EXCRET_FTYPE_MASK; + } + lr = deposit32(lr, 24, 8, 0xff); + } + + if (arm_feature(env, ARM_FEATURE_V8)) { + if (arm_feature(env, ARM_FEATURE_M_SECURITY) && + (lr & R_V7M_EXCRET_S_MASK)) { + /* + * The background code (the owner of the registers in the + * exception frame) is Secure. This means it may either already + * have or now needs to push callee-saves registers. + */ + if (targets_secure) { + if (dotailchain && !(lr & R_V7M_EXCRET_ES_MASK)) { + /* + * We took an exception from Secure to NonSecure + * (which means the callee-saved registers got stacked) + * and are now tailchaining to a Secure exception. + * Clear DCRS so eventual return from this Secure + * exception unstacks the callee-saved registers. + */ + lr &= ~R_V7M_EXCRET_DCRS_MASK; + } + } else { + /* + * We're going to a non-secure exception; push the + * callee-saves registers to the stack now, if they're + * not already saved. + */ + if (lr & R_V7M_EXCRET_DCRS_MASK && + !(dotailchain && !(lr & R_V7M_EXCRET_ES_MASK))) { + push_failed = v7m_push_callee_stack(cpu, lr, dotailchain, + ignore_stackfaults); + } + lr |= R_V7M_EXCRET_DCRS_MASK; + } + } + + lr &= ~R_V7M_EXCRET_ES_MASK; + if (targets_secure) { + lr |= R_V7M_EXCRET_ES_MASK; + } + lr &= ~R_V7M_EXCRET_SPSEL_MASK; + if (env->v7m.control[targets_secure] & R_V7M_CONTROL_SPSEL_MASK) { + lr |= R_V7M_EXCRET_SPSEL_MASK; + } + + /* + * Clear registers if necessary to prevent non-secure exception + * code being able to see register values from secure code. + * Where register values become architecturally UNKNOWN we leave + * them with their previous values. v8.1M is tighter than v8.0M + * here and always zeroes the caller-saved registers regardless + * of the security state the exception is targeting. + */ + if (arm_feature(env, ARM_FEATURE_M_SECURITY)) { + if (!targets_secure || arm_feature(env, ARM_FEATURE_V8_1M)) { + /* + * Always clear the caller-saved registers (they have been + * pushed to the stack earlier in v7m_push_stack()). + * Clear callee-saved registers if the background code is + * Secure (in which case these regs were saved in + * v7m_push_callee_stack()). + */ + int i; + /* + * r4..r11 are callee-saves, zero only if background + * state was Secure (EXCRET.S == 1) and exception + * targets Non-secure state + */ + bool zero_callee_saves = !targets_secure && + (lr & R_V7M_EXCRET_S_MASK); + + for (i = 0; i < 13; i++) { + if (i < 4 || i > 11 || zero_callee_saves) { + env->regs[i] = 0; + } + } + /* Clear EAPSR */ + xpsr_write(env, 0, XPSR_NZCV | XPSR_Q | XPSR_GE | XPSR_IT); + } + } + } + + if (push_failed && !ignore_stackfaults) { + /* + * Derived exception on callee-saves register stacking: + * we might now want to take a different exception which + * targets a different security state, so try again from the top. + */ + qemu_log_mask(CPU_LOG_INT, + "...derived exception on callee-saves register stacking"); + v7m_exception_taken(cpu, lr, true, true); + return; + } + + if (!arm_v7m_load_vector(cpu, exc, targets_secure, &addr)) { + /* Vector load failed: derived exception */ + qemu_log_mask(CPU_LOG_INT, "...derived exception on vector table load"); + v7m_exception_taken(cpu, lr, true, true); + return; + } + + /* + * Now we've done everything that might cause a derived exception + * we can go ahead and activate whichever exception we're going to + * take (which might now be the derived exception). + */ + armv7m_nvic_acknowledge_irq(env->nvic); + + /* Switch to target security state -- must do this before writing SPSEL */ + switch_v7m_security_state(env, targets_secure); + write_v7m_control_spsel(env, 0); + arm_clear_exclusive(env); + /* Clear SFPA and FPCA (has no effect if no FPU) */ + env->v7m.control[M_REG_S] &= + ~(R_V7M_CONTROL_FPCA_MASK | R_V7M_CONTROL_SFPA_MASK); + /* Clear IT bits */ + env->condexec_bits = 0; + env->regs[14] = lr; + env->regs[15] = addr & 0xfffffffe; + env->thumb = addr & 1; + arm_rebuild_hflags(env); +} + +static void v7m_update_fpccr(CPUARMState *env, uint32_t frameptr, + bool apply_splim) +{ + /* + * Like the pseudocode UpdateFPCCR: save state in FPCAR and FPCCR + * that we will need later in order to do lazy FP reg stacking. + */ + bool is_secure = env->v7m.secure; + NVICState *nvic = env->nvic; + /* + * Some bits are unbanked and live always in fpccr[M_REG_S]; some bits + * are banked and we want to update the bit in the bank for the + * current security state; and in one case we want to specifically + * update the NS banked version of a bit even if we are secure. + */ + uint32_t *fpccr_s = &env->v7m.fpccr[M_REG_S]; + uint32_t *fpccr_ns = &env->v7m.fpccr[M_REG_NS]; + uint32_t *fpccr = &env->v7m.fpccr[is_secure]; + bool hfrdy, bfrdy, mmrdy, ns_ufrdy, s_ufrdy, sfrdy, monrdy; + + env->v7m.fpcar[is_secure] = frameptr & ~0x7; + + if (apply_splim && arm_feature(env, ARM_FEATURE_V8)) { + bool splimviol; + uint32_t splim = v7m_sp_limit(env); + bool ign = armv7m_nvic_neg_prio_requested(nvic, is_secure) && + (env->v7m.ccr[is_secure] & R_V7M_CCR_STKOFHFNMIGN_MASK); + + splimviol = !ign && frameptr < splim; + *fpccr = FIELD_DP32(*fpccr, V7M_FPCCR, SPLIMVIOL, splimviol); + } + + *fpccr = FIELD_DP32(*fpccr, V7M_FPCCR, LSPACT, 1); + + *fpccr_s = FIELD_DP32(*fpccr_s, V7M_FPCCR, S, is_secure); + + *fpccr = FIELD_DP32(*fpccr, V7M_FPCCR, USER, arm_current_el(env) == 0); + + *fpccr = FIELD_DP32(*fpccr, V7M_FPCCR, THREAD, + !arm_v7m_is_handler_mode(env)); + + hfrdy = armv7m_nvic_get_ready_status(nvic, ARMV7M_EXCP_HARD, false); + *fpccr_s = FIELD_DP32(*fpccr_s, V7M_FPCCR, HFRDY, hfrdy); + + bfrdy = armv7m_nvic_get_ready_status(nvic, ARMV7M_EXCP_BUS, false); + *fpccr_s = FIELD_DP32(*fpccr_s, V7M_FPCCR, BFRDY, bfrdy); + + mmrdy = armv7m_nvic_get_ready_status(nvic, ARMV7M_EXCP_MEM, is_secure); + *fpccr = FIELD_DP32(*fpccr, V7M_FPCCR, MMRDY, mmrdy); + + ns_ufrdy = armv7m_nvic_get_ready_status(nvic, ARMV7M_EXCP_USAGE, false); + *fpccr_ns = FIELD_DP32(*fpccr_ns, V7M_FPCCR, UFRDY, ns_ufrdy); + + monrdy = armv7m_nvic_get_ready_status(nvic, ARMV7M_EXCP_DEBUG, false); + *fpccr_s = FIELD_DP32(*fpccr_s, V7M_FPCCR, MONRDY, monrdy); + + if (arm_feature(env, ARM_FEATURE_M_SECURITY)) { + s_ufrdy = armv7m_nvic_get_ready_status(nvic, ARMV7M_EXCP_USAGE, true); + *fpccr_s = FIELD_DP32(*fpccr_s, V7M_FPCCR, UFRDY, s_ufrdy); + + sfrdy = armv7m_nvic_get_ready_status(nvic, ARMV7M_EXCP_SECURE, false); + *fpccr_s = FIELD_DP32(*fpccr_s, V7M_FPCCR, SFRDY, sfrdy); + } +} + +void HELPER(v7m_vlstm)(CPUARMState *env, uint32_t fptr) +{ + /* fptr is the value of Rn, the frame pointer we store the FP regs to */ + ARMCPU *cpu = env_archcpu(env); + bool s = env->v7m.fpccr[M_REG_S] & R_V7M_FPCCR_S_MASK; + bool lspact = env->v7m.fpccr[s] & R_V7M_FPCCR_LSPACT_MASK; + uintptr_t ra = GETPC(); + + assert(env->v7m.secure); + + if (!(env->v7m.control[M_REG_S] & R_V7M_CONTROL_SFPA_MASK)) { + return; + } + + /* Check access to the coprocessor is permitted */ + if (!v7m_cpacr_pass(env, true, arm_current_el(env) != 0)) { + raise_exception_ra(env, EXCP_NOCP, 0, 1, GETPC()); + } + + if (lspact) { + /* LSPACT should not be active when there is active FP state */ + raise_exception_ra(env, EXCP_LSERR, 0, 1, GETPC()); + } + + if (fptr & 7) { + raise_exception_ra(env, EXCP_UNALIGNED, 0, 1, GETPC()); + } + + /* + * Note that we do not use v7m_stack_write() here, because the + * accesses should not set the FSR bits for stacking errors if they + * fail. (In pseudocode terms, they are AccType_NORMAL, not AccType_STACK + * or AccType_LAZYFP). Faults in cpu_stl_data_ra() will throw exceptions + * and longjmp out. + */ + if (!(env->v7m.fpccr[M_REG_S] & R_V7M_FPCCR_LSPEN_MASK)) { + bool ts = env->v7m.fpccr[M_REG_S] & R_V7M_FPCCR_TS_MASK; + int i; + + for (i = 0; i < (ts ? 32 : 16); i += 2) { + uint64_t dn = *aa32_vfp_dreg(env, i / 2); + uint32_t faddr = fptr + 4 * i; + uint32_t slo = extract64(dn, 0, 32); + uint32_t shi = extract64(dn, 32, 32); + + if (i >= 16) { + faddr += 8; /* skip the slot for the FPSCR */ + } + cpu_stl_data_ra(env, faddr, slo, ra); + cpu_stl_data_ra(env, faddr + 4, shi, ra); + } + cpu_stl_data_ra(env, fptr + 0x40, vfp_get_fpscr(env), ra); + if (cpu_isar_feature(aa32_mve, cpu)) { + cpu_stl_data_ra(env, fptr + 0x44, env->v7m.vpr, ra); + } + + /* + * If TS is 0 then s0 to s15, FPSCR and VPR are UNKNOWN; we choose to + * leave them unchanged, matching our choice in v7m_preserve_fp_state. + */ + if (ts) { + for (i = 0; i < 32; i += 2) { + *aa32_vfp_dreg(env, i / 2) = 0; + } + vfp_set_fpscr(env, 0); + if (cpu_isar_feature(aa32_mve, cpu)) { + env->v7m.vpr = 0; + } + } + } else { + v7m_update_fpccr(env, fptr, false); + } + + env->v7m.control[M_REG_S] &= ~R_V7M_CONTROL_FPCA_MASK; +} + +void HELPER(v7m_vlldm)(CPUARMState *env, uint32_t fptr) +{ + ARMCPU *cpu = env_archcpu(env); + uintptr_t ra = GETPC(); + + /* fptr is the value of Rn, the frame pointer we load the FP regs from */ + assert(env->v7m.secure); + + if (!(env->v7m.control[M_REG_S] & R_V7M_CONTROL_SFPA_MASK)) { + return; + } + + /* Check access to the coprocessor is permitted */ + if (!v7m_cpacr_pass(env, true, arm_current_el(env) != 0)) { + raise_exception_ra(env, EXCP_NOCP, 0, 1, GETPC()); + } + + if (env->v7m.fpccr[M_REG_S] & R_V7M_FPCCR_LSPACT_MASK) { + /* State in FP is still valid */ + env->v7m.fpccr[M_REG_S] &= ~R_V7M_FPCCR_LSPACT_MASK; + } else { + bool ts = env->v7m.fpccr[M_REG_S] & R_V7M_FPCCR_TS_MASK; + int i; + uint32_t fpscr; + + if (fptr & 7) { + raise_exception_ra(env, EXCP_UNALIGNED, 0, 1, GETPC()); + } + + for (i = 0; i < (ts ? 32 : 16); i += 2) { + uint32_t slo, shi; + uint64_t dn; + uint32_t faddr = fptr + 4 * i; + + if (i >= 16) { + faddr += 8; /* skip the slot for the FPSCR and VPR */ + } + + slo = cpu_ldl_data_ra(env, faddr, ra); + shi = cpu_ldl_data_ra(env, faddr + 4, ra); + + dn = (uint64_t) shi << 32 | slo; + *aa32_vfp_dreg(env, i / 2) = dn; + } + fpscr = cpu_ldl_data_ra(env, fptr + 0x40, ra); + vfp_set_fpscr(env, fpscr); + if (cpu_isar_feature(aa32_mve, cpu)) { + env->v7m.vpr = cpu_ldl_data_ra(env, fptr + 0x44, ra); + } + } + + env->v7m.control[M_REG_S] |= R_V7M_CONTROL_FPCA_MASK; +} + +static bool v7m_push_stack(ARMCPU *cpu) +{ + /* + * Do the "set up stack frame" part of exception entry, + * similar to pseudocode PushStack(). + * Return true if we generate a derived exception (and so + * should ignore further stack faults trying to process + * that derived exception.) + */ + bool stacked_ok = true, limitviol = false; + CPUARMState *env = &cpu->env; + uint32_t xpsr = xpsr_read(env); + uint32_t frameptr = env->regs[13]; + ARMMMUIdx mmu_idx = arm_mmu_idx(env); + uint32_t framesize; + bool nsacr_cp10 = extract32(env->v7m.nsacr, 10, 1); + + if ((env->v7m.control[M_REG_S] & R_V7M_CONTROL_FPCA_MASK) && + (env->v7m.secure || nsacr_cp10)) { + if (env->v7m.secure && + env->v7m.fpccr[M_REG_S] & R_V7M_FPCCR_TS_MASK) { + framesize = 0xa8; + } else { + framesize = 0x68; + } + } else { + framesize = 0x20; + } + + /* Align stack pointer if the guest wants that */ + if ((frameptr & 4) && + (env->v7m.ccr[env->v7m.secure] & R_V7M_CCR_STKALIGN_MASK)) { + frameptr -= 4; + xpsr |= XPSR_SPREALIGN; + } + + xpsr &= ~XPSR_SFPA; + if (env->v7m.secure && + (env->v7m.control[M_REG_S] & R_V7M_CONTROL_SFPA_MASK)) { + xpsr |= XPSR_SFPA; + } + + frameptr -= framesize; + + if (arm_feature(env, ARM_FEATURE_V8)) { + uint32_t limit = v7m_sp_limit(env); + + if (frameptr < limit) { + /* + * Stack limit failure: set SP to the limit value, and generate + * STKOF UsageFault. Stack pushes below the limit must not be + * performed. It is IMPDEF whether pushes above the limit are + * performed; we choose not to. + */ + qemu_log_mask(CPU_LOG_INT, + "...STKOF during stacking\n"); + env->v7m.cfsr[env->v7m.secure] |= R_V7M_CFSR_STKOF_MASK; + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE, + env->v7m.secure); + env->regs[13] = limit; + /* + * We won't try to perform any further memory accesses but + * we must continue through the following code to check for + * permission faults during FPU state preservation, and we + * must update FPCCR if lazy stacking is enabled. + */ + limitviol = true; + stacked_ok = false; + } + } + + /* + * Write as much of the stack frame as we can. If we fail a stack + * write this will result in a derived exception being pended + * (which may be taken in preference to the one we started with + * if it has higher priority). + */ + stacked_ok = stacked_ok && + v7m_stack_write(cpu, frameptr, env->regs[0], mmu_idx, STACK_NORMAL) && + v7m_stack_write(cpu, frameptr + 4, env->regs[1], + mmu_idx, STACK_NORMAL) && + v7m_stack_write(cpu, frameptr + 8, env->regs[2], + mmu_idx, STACK_NORMAL) && + v7m_stack_write(cpu, frameptr + 12, env->regs[3], + mmu_idx, STACK_NORMAL) && + v7m_stack_write(cpu, frameptr + 16, env->regs[12], + mmu_idx, STACK_NORMAL) && + v7m_stack_write(cpu, frameptr + 20, env->regs[14], + mmu_idx, STACK_NORMAL) && + v7m_stack_write(cpu, frameptr + 24, env->regs[15], + mmu_idx, STACK_NORMAL) && + v7m_stack_write(cpu, frameptr + 28, xpsr, mmu_idx, STACK_NORMAL); + + if (env->v7m.control[M_REG_S] & R_V7M_CONTROL_FPCA_MASK) { + /* FPU is active, try to save its registers */ + bool fpccr_s = env->v7m.fpccr[M_REG_S] & R_V7M_FPCCR_S_MASK; + bool lspact = env->v7m.fpccr[fpccr_s] & R_V7M_FPCCR_LSPACT_MASK; + + if (lspact && arm_feature(env, ARM_FEATURE_M_SECURITY)) { + qemu_log_mask(CPU_LOG_INT, + "...SecureFault because LSPACT and FPCA both set\n"); + env->v7m.sfsr |= R_V7M_SFSR_LSERR_MASK; + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_SECURE, false); + } else if (!env->v7m.secure && !nsacr_cp10) { + qemu_log_mask(CPU_LOG_INT, + "...Secure UsageFault with CFSR.NOCP because " + "NSACR.CP10 prevents stacking FP regs\n"); + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE, M_REG_S); + env->v7m.cfsr[M_REG_S] |= R_V7M_CFSR_NOCP_MASK; + } else { + if (!(env->v7m.fpccr[M_REG_S] & R_V7M_FPCCR_LSPEN_MASK)) { + /* Lazy stacking disabled, save registers now */ + int i; + bool cpacr_pass = v7m_cpacr_pass(env, env->v7m.secure, + arm_current_el(env) != 0); + + if (stacked_ok && !cpacr_pass) { + /* + * Take UsageFault if CPACR forbids access. The pseudocode + * here does a full CheckCPEnabled() but we know the NSACR + * check can never fail as we have already handled that. + */ + qemu_log_mask(CPU_LOG_INT, + "...UsageFault with CFSR.NOCP because " + "CPACR.CP10 prevents stacking FP regs\n"); + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE, + env->v7m.secure); + env->v7m.cfsr[env->v7m.secure] |= R_V7M_CFSR_NOCP_MASK; + stacked_ok = false; + } + + for (i = 0; i < ((framesize == 0xa8) ? 32 : 16); i += 2) { + uint64_t dn = *aa32_vfp_dreg(env, i / 2); + uint32_t faddr = frameptr + 0x20 + 4 * i; + uint32_t slo = extract64(dn, 0, 32); + uint32_t shi = extract64(dn, 32, 32); + + if (i >= 16) { + faddr += 8; /* skip the slot for the FPSCR and VPR */ + } + stacked_ok = stacked_ok && + v7m_stack_write(cpu, faddr, slo, + mmu_idx, STACK_NORMAL) && + v7m_stack_write(cpu, faddr + 4, shi, + mmu_idx, STACK_NORMAL); + } + stacked_ok = stacked_ok && + v7m_stack_write(cpu, frameptr + 0x60, + vfp_get_fpscr(env), mmu_idx, STACK_NORMAL); + if (cpu_isar_feature(aa32_mve, cpu)) { + stacked_ok = stacked_ok && + v7m_stack_write(cpu, frameptr + 0x64, + env->v7m.vpr, mmu_idx, STACK_NORMAL); + } + if (cpacr_pass) { + for (i = 0; i < ((framesize == 0xa8) ? 32 : 16); i += 2) { + *aa32_vfp_dreg(env, i / 2) = 0; + } + vfp_set_fpscr(env, 0); + if (cpu_isar_feature(aa32_mve, cpu)) { + env->v7m.vpr = 0; + } + } + } else { + /* Lazy stacking enabled, save necessary info to stack later */ + v7m_update_fpccr(env, frameptr + 0x20, true); + } + } + } + + /* + * If we broke a stack limit then SP was already updated earlier; + * otherwise we update SP regardless of whether any of the stack + * accesses failed or we took some other kind of fault. + */ + if (!limitviol) { + env->regs[13] = frameptr; + } + + return !stacked_ok; +} + +static void do_v7m_exception_exit(ARMCPU *cpu) +{ + CPUARMState *env = &cpu->env; + uint32_t excret; + uint32_t xpsr, xpsr_mask; + bool ufault = false; + bool sfault = false; + bool return_to_sp_process; + bool return_to_handler; + bool rettobase = false; + bool exc_secure = false; + bool return_to_secure; + bool ftype; + bool restore_s16_s31 = false; + + /* + * If we're not in Handler mode then jumps to magic exception-exit + * addresses don't have magic behaviour. However for the v8M + * security extensions the magic secure-function-return has to + * work in thread mode too, so to avoid doing an extra check in + * the generated code we allow exception-exit magic to also cause the + * internal exception and bring us here in thread mode. Correct code + * will never try to do this (the following insn fetch will always + * fault) so we the overhead of having taken an unnecessary exception + * doesn't matter. + */ + if (!arm_v7m_is_handler_mode(env)) { + return; + } + + /* + * In the spec pseudocode ExceptionReturn() is called directly + * from BXWritePC() and gets the full target PC value including + * bit zero. In QEMU's implementation we treat it as a normal + * jump-to-register (which is then caught later on), and so split + * the target value up between env->regs[15] and env->thumb in + * gen_bx(). Reconstitute it. + */ + excret = env->regs[15]; + if (env->thumb) { + excret |= 1; + } + + qemu_log_mask(CPU_LOG_INT, "Exception return: magic PC %" PRIx32 + " previous exception %d\n", + excret, env->v7m.exception); + + if ((excret & R_V7M_EXCRET_RES1_MASK) != R_V7M_EXCRET_RES1_MASK) { + qemu_log_mask(LOG_GUEST_ERROR, "M profile: zero high bits in exception " + "exit PC value 0x%" PRIx32 " are UNPREDICTABLE\n", + excret); + } + + ftype = excret & R_V7M_EXCRET_FTYPE_MASK; + + if (!ftype && !cpu_isar_feature(aa32_vfp_simd, cpu)) { + qemu_log_mask(LOG_GUEST_ERROR, "M profile: zero FTYPE in exception " + "exit PC value 0x%" PRIx32 " is UNPREDICTABLE " + "if FPU not present\n", + excret); + ftype = true; + } + + if (arm_feature(env, ARM_FEATURE_M_SECURITY)) { + /* + * EXC_RETURN.ES validation check (R_SMFL). We must do this before + * we pick which FAULTMASK to clear. + */ + if (!env->v7m.secure && + ((excret & R_V7M_EXCRET_ES_MASK) || + !(excret & R_V7M_EXCRET_DCRS_MASK))) { + sfault = 1; + /* For all other purposes, treat ES as 0 (R_HXSR) */ + excret &= ~R_V7M_EXCRET_ES_MASK; + } + exc_secure = excret & R_V7M_EXCRET_ES_MASK; + } + + if (env->v7m.exception != ARMV7M_EXCP_NMI) { + /* + * Auto-clear FAULTMASK on return from other than NMI. + * If the security extension is implemented then this only + * happens if the raw execution priority is >= 0; the + * value of the ES bit in the exception return value indicates + * which security state's faultmask to clear. (v8M ARM ARM R_KBNF.) + */ + if (arm_feature(env, ARM_FEATURE_M_SECURITY)) { + if (armv7m_nvic_raw_execution_priority(env->nvic) >= 0) { + env->v7m.faultmask[exc_secure] = 0; + } + } else { + env->v7m.faultmask[M_REG_NS] = 0; + } + } + + switch (armv7m_nvic_complete_irq(env->nvic, env->v7m.exception, + exc_secure)) { + case -1: + /* attempt to exit an exception that isn't active */ + ufault = true; + break; + case 0: + /* still an irq active now */ + break; + case 1: + /* + * We returned to base exception level, no nesting. + * (In the pseudocode this is written using "NestedActivation != 1" + * where we have 'rettobase == false'.) + */ + rettobase = true; + break; + default: + g_assert_not_reached(); + } + + return_to_handler = !(excret & R_V7M_EXCRET_MODE_MASK); + return_to_sp_process = excret & R_V7M_EXCRET_SPSEL_MASK; + return_to_secure = arm_feature(env, ARM_FEATURE_M_SECURITY) && + (excret & R_V7M_EXCRET_S_MASK); + + if (arm_feature(env, ARM_FEATURE_V8)) { + if (!arm_feature(env, ARM_FEATURE_M_SECURITY)) { + /* + * UNPREDICTABLE if S == 1 or DCRS == 0 or ES == 1 (R_XLCP); + * we choose to take the UsageFault. + */ + if ((excret & R_V7M_EXCRET_S_MASK) || + (excret & R_V7M_EXCRET_ES_MASK) || + !(excret & R_V7M_EXCRET_DCRS_MASK)) { + ufault = true; + } + } + if (excret & R_V7M_EXCRET_RES0_MASK) { + ufault = true; + } + } else { + /* For v7M we only recognize certain combinations of the low bits */ + switch (excret & 0xf) { + case 1: /* Return to Handler */ + break; + case 13: /* Return to Thread using Process stack */ + case 9: /* Return to Thread using Main stack */ + /* + * We only need to check NONBASETHRDENA for v7M, because in + * v8M this bit does not exist (it is RES1). + */ + if (!rettobase && + !(env->v7m.ccr[env->v7m.secure] & + R_V7M_CCR_NONBASETHRDENA_MASK)) { + ufault = true; + } + break; + default: + ufault = true; + } + } + + /* + * Set CONTROL.SPSEL from excret.SPSEL. Since we're still in + * Handler mode (and will be until we write the new XPSR.Interrupt + * field) this does not switch around the current stack pointer. + * We must do this before we do any kind of tailchaining, including + * for the derived exceptions on integrity check failures, or we will + * give the guest an incorrect EXCRET.SPSEL value on exception entry. + */ + write_v7m_control_spsel_for_secstate(env, return_to_sp_process, exc_secure); + + /* + * Clear scratch FP values left in caller saved registers; this + * must happen before any kind of tail chaining. + */ + if ((env->v7m.fpccr[M_REG_S] & R_V7M_FPCCR_CLRONRET_MASK) && + (env->v7m.control[M_REG_S] & R_V7M_CONTROL_FPCA_MASK)) { + if (env->v7m.fpccr[M_REG_S] & R_V7M_FPCCR_LSPACT_MASK) { + env->v7m.sfsr |= R_V7M_SFSR_LSERR_MASK; + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_SECURE, false); + qemu_log_mask(CPU_LOG_INT, "...taking SecureFault on existing " + "stackframe: error during lazy state deactivation\n"); + v7m_exception_taken(cpu, excret, true, false); + return; + } else { + if (arm_feature(env, ARM_FEATURE_V8_1M)) { + /* v8.1M adds this NOCP check */ + bool nsacr_pass = exc_secure || + extract32(env->v7m.nsacr, 10, 1); + bool cpacr_pass = v7m_cpacr_pass(env, exc_secure, true); + if (!nsacr_pass) { + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE, true); + env->v7m.cfsr[M_REG_S] |= R_V7M_CFSR_NOCP_MASK; + qemu_log_mask(CPU_LOG_INT, "...taking UsageFault on existing " + "stackframe: NSACR prevents clearing FPU registers\n"); + v7m_exception_taken(cpu, excret, true, false); + return; + } else if (!cpacr_pass) { + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE, + exc_secure); + env->v7m.cfsr[exc_secure] |= R_V7M_CFSR_NOCP_MASK; + qemu_log_mask(CPU_LOG_INT, "...taking UsageFault on existing " + "stackframe: CPACR prevents clearing FPU registers\n"); + v7m_exception_taken(cpu, excret, true, false); + return; + } + } + /* Clear s0..s15, FPSCR and VPR */ + int i; + + for (i = 0; i < 16; i += 2) { + *aa32_vfp_dreg(env, i / 2) = 0; + } + vfp_set_fpscr(env, 0); + if (cpu_isar_feature(aa32_mve, cpu)) { + env->v7m.vpr = 0; + } + } + } + + if (sfault) { + env->v7m.sfsr |= R_V7M_SFSR_INVER_MASK; + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_SECURE, false); + qemu_log_mask(CPU_LOG_INT, "...taking SecureFault on existing " + "stackframe: failed EXC_RETURN.ES validity check\n"); + v7m_exception_taken(cpu, excret, true, false); + return; + } + + if (ufault) { + /* + * Bad exception return: instead of popping the exception + * stack, directly take a usage fault on the current stack. + */ + env->v7m.cfsr[env->v7m.secure] |= R_V7M_CFSR_INVPC_MASK; + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE, env->v7m.secure); + qemu_log_mask(CPU_LOG_INT, "...taking UsageFault on existing " + "stackframe: failed exception return integrity check\n"); + v7m_exception_taken(cpu, excret, true, false); + return; + } + + /* + * Tailchaining: if there is currently a pending exception that + * is high enough priority to preempt execution at the level we're + * about to return to, then just directly take that exception now, + * avoiding an unstack-and-then-stack. Note that now we have + * deactivated the previous exception by calling armv7m_nvic_complete_irq() + * our current execution priority is already the execution priority we are + * returning to -- none of the state we would unstack or set based on + * the EXCRET value affects it. + */ + if (armv7m_nvic_can_take_pending_exception(env->nvic)) { + qemu_log_mask(CPU_LOG_INT, "...tailchaining to pending exception\n"); + v7m_exception_taken(cpu, excret, true, false); + return; + } + + switch_v7m_security_state(env, return_to_secure); + + { + /* + * The stack pointer we should be reading the exception frame from + * depends on bits in the magic exception return type value (and + * for v8M isn't necessarily the stack pointer we will eventually + * end up resuming execution with). Get a pointer to the location + * in the CPU state struct where the SP we need is currently being + * stored; we will use and modify it in place. + * We use this limited C variable scope so we don't accidentally + * use 'frame_sp_p' after we do something that makes it invalid. + */ + bool spsel = env->v7m.control[return_to_secure] & R_V7M_CONTROL_SPSEL_MASK; + uint32_t *frame_sp_p = get_v7m_sp_ptr(env, + return_to_secure, + !return_to_handler, + spsel); + uint32_t frameptr = *frame_sp_p; + bool pop_ok = true; + ARMMMUIdx mmu_idx; + bool return_to_priv = return_to_handler || + !(env->v7m.control[return_to_secure] & R_V7M_CONTROL_NPRIV_MASK); + + mmu_idx = arm_v7m_mmu_idx_for_secstate_and_priv(env, return_to_secure, + return_to_priv); + + if (!QEMU_IS_ALIGNED(frameptr, 8) && + arm_feature(env, ARM_FEATURE_V8)) { + qemu_log_mask(LOG_GUEST_ERROR, + "M profile exception return with non-8-aligned SP " + "for destination state is UNPREDICTABLE\n"); + } + + /* Do we need to pop callee-saved registers? */ + if (return_to_secure && + ((excret & R_V7M_EXCRET_ES_MASK) == 0 || + (excret & R_V7M_EXCRET_DCRS_MASK) == 0)) { + uint32_t actual_sig; + + pop_ok = v7m_stack_read(cpu, &actual_sig, frameptr, mmu_idx); + + if (pop_ok && v7m_integrity_sig(env, excret) != actual_sig) { + /* Take a SecureFault on the current stack */ + env->v7m.sfsr |= R_V7M_SFSR_INVIS_MASK; + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_SECURE, false); + qemu_log_mask(CPU_LOG_INT, "...taking SecureFault on existing " + "stackframe: failed exception return integrity " + "signature check\n"); + v7m_exception_taken(cpu, excret, true, false); + return; + } + + pop_ok = pop_ok && + v7m_stack_read(cpu, &env->regs[4], frameptr + 0x8, mmu_idx) && + v7m_stack_read(cpu, &env->regs[5], frameptr + 0xc, mmu_idx) && + v7m_stack_read(cpu, &env->regs[6], frameptr + 0x10, mmu_idx) && + v7m_stack_read(cpu, &env->regs[7], frameptr + 0x14, mmu_idx) && + v7m_stack_read(cpu, &env->regs[8], frameptr + 0x18, mmu_idx) && + v7m_stack_read(cpu, &env->regs[9], frameptr + 0x1c, mmu_idx) && + v7m_stack_read(cpu, &env->regs[10], frameptr + 0x20, mmu_idx) && + v7m_stack_read(cpu, &env->regs[11], frameptr + 0x24, mmu_idx); + + frameptr += 0x28; + } + + /* Pop registers */ + pop_ok = pop_ok && + v7m_stack_read(cpu, &env->regs[0], frameptr, mmu_idx) && + v7m_stack_read(cpu, &env->regs[1], frameptr + 0x4, mmu_idx) && + v7m_stack_read(cpu, &env->regs[2], frameptr + 0x8, mmu_idx) && + v7m_stack_read(cpu, &env->regs[3], frameptr + 0xc, mmu_idx) && + v7m_stack_read(cpu, &env->regs[12], frameptr + 0x10, mmu_idx) && + v7m_stack_read(cpu, &env->regs[14], frameptr + 0x14, mmu_idx) && + v7m_stack_read(cpu, &env->regs[15], frameptr + 0x18, mmu_idx) && + v7m_stack_read(cpu, &xpsr, frameptr + 0x1c, mmu_idx); + + if (!pop_ok) { + /* + * v7m_stack_read() pended a fault, so take it (as a tail + * chained exception on the same stack frame) + */ + qemu_log_mask(CPU_LOG_INT, "...derived exception on unstacking\n"); + v7m_exception_taken(cpu, excret, true, false); + return; + } + + /* + * Returning from an exception with a PC with bit 0 set is defined + * behaviour on v8M (bit 0 is ignored), but for v7M it was specified + * to be UNPREDICTABLE. In practice actual v7M hardware seems to ignore + * the lsbit, and there are several RTOSes out there which incorrectly + * assume the r15 in the stack frame should be a Thumb-style "lsbit + * indicates ARM/Thumb" value, so ignore the bit on v7M as well, but + * complain about the badly behaved guest. + */ + if (env->regs[15] & 1) { + env->regs[15] &= ~1U; + if (!arm_feature(env, ARM_FEATURE_V8)) { + qemu_log_mask(LOG_GUEST_ERROR, + "M profile return from interrupt with misaligned " + "PC is UNPREDICTABLE on v7M\n"); + } + } + + if (arm_feature(env, ARM_FEATURE_V8)) { + /* + * For v8M we have to check whether the xPSR exception field + * matches the EXCRET value for return to handler/thread + * before we commit to changing the SP and xPSR. + */ + bool will_be_handler = (xpsr & XPSR_EXCP) != 0; + if (return_to_handler != will_be_handler) { + /* + * Take an INVPC UsageFault on the current stack. + * By this point we will have switched to the security state + * for the background state, so this UsageFault will target + * that state. + */ + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE, + env->v7m.secure); + env->v7m.cfsr[env->v7m.secure] |= R_V7M_CFSR_INVPC_MASK; + qemu_log_mask(CPU_LOG_INT, "...taking UsageFault on existing " + "stackframe: failed exception return integrity " + "check\n"); + v7m_exception_taken(cpu, excret, true, false); + return; + } + } + + if (!ftype) { + /* FP present and we need to handle it */ + if (!return_to_secure && + (env->v7m.fpccr[M_REG_S] & R_V7M_FPCCR_LSPACT_MASK)) { + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_SECURE, false); + env->v7m.sfsr |= R_V7M_SFSR_LSERR_MASK; + qemu_log_mask(CPU_LOG_INT, + "...taking SecureFault on existing stackframe: " + "Secure LSPACT set but exception return is " + "not to secure state\n"); + v7m_exception_taken(cpu, excret, true, false); + return; + } + + restore_s16_s31 = return_to_secure && + (env->v7m.fpccr[M_REG_S] & R_V7M_FPCCR_TS_MASK); + + if (env->v7m.fpccr[return_to_secure] & R_V7M_FPCCR_LSPACT_MASK) { + /* State in FPU is still valid, just clear LSPACT */ + env->v7m.fpccr[return_to_secure] &= ~R_V7M_FPCCR_LSPACT_MASK; + } else { + int i; + uint32_t fpscr; + bool cpacr_pass, nsacr_pass; + + cpacr_pass = v7m_cpacr_pass(env, return_to_secure, + return_to_priv); + nsacr_pass = return_to_secure || + extract32(env->v7m.nsacr, 10, 1); + + if (!cpacr_pass) { + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE, + return_to_secure); + env->v7m.cfsr[return_to_secure] |= R_V7M_CFSR_NOCP_MASK; + qemu_log_mask(CPU_LOG_INT, + "...taking UsageFault on existing " + "stackframe: CPACR.CP10 prevents unstacking " + "FP regs\n"); + v7m_exception_taken(cpu, excret, true, false); + return; + } else if (!nsacr_pass) { + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE, true); + env->v7m.cfsr[M_REG_S] |= R_V7M_CFSR_INVPC_MASK; + qemu_log_mask(CPU_LOG_INT, + "...taking Secure UsageFault on existing " + "stackframe: NSACR.CP10 prevents unstacking " + "FP regs\n"); + v7m_exception_taken(cpu, excret, true, false); + return; + } + + for (i = 0; i < (restore_s16_s31 ? 32 : 16); i += 2) { + uint32_t slo, shi; + uint64_t dn; + uint32_t faddr = frameptr + 0x20 + 4 * i; + + if (i >= 16) { + faddr += 8; /* Skip the slot for the FPSCR and VPR */ + } + + pop_ok = pop_ok && + v7m_stack_read(cpu, &slo, faddr, mmu_idx) && + v7m_stack_read(cpu, &shi, faddr + 4, mmu_idx); + + if (!pop_ok) { + break; + } + + dn = (uint64_t)shi << 32 | slo; + *aa32_vfp_dreg(env, i / 2) = dn; + } + pop_ok = pop_ok && + v7m_stack_read(cpu, &fpscr, frameptr + 0x60, mmu_idx); + if (pop_ok) { + vfp_set_fpscr(env, fpscr); + } + if (cpu_isar_feature(aa32_mve, cpu)) { + pop_ok = pop_ok && + v7m_stack_read(cpu, &env->v7m.vpr, + frameptr + 0x64, mmu_idx); + } + if (!pop_ok) { + /* + * These regs are 0 if security extension present; + * otherwise merely UNKNOWN. We zero always. + */ + for (i = 0; i < (restore_s16_s31 ? 32 : 16); i += 2) { + *aa32_vfp_dreg(env, i / 2) = 0; + } + vfp_set_fpscr(env, 0); + if (cpu_isar_feature(aa32_mve, cpu)) { + env->v7m.vpr = 0; + } + } + } + } + env->v7m.control[M_REG_S] = FIELD_DP32(env->v7m.control[M_REG_S], + V7M_CONTROL, FPCA, !ftype); + + /* Commit to consuming the stack frame */ + frameptr += 0x20; + if (!ftype) { + frameptr += 0x48; + if (restore_s16_s31) { + frameptr += 0x40; + } + } + /* + * Undo stack alignment (the SPREALIGN bit indicates that the original + * pre-exception SP was not 8-aligned and we added a padding word to + * align it, so we undo this by ORing in the bit that increases it + * from the current 8-aligned value to the 8-unaligned value. (Adding 4 + * would work too but a logical OR is how the pseudocode specifies it.) + */ + if (xpsr & XPSR_SPREALIGN) { + frameptr |= 4; + } + *frame_sp_p = frameptr; + } + + xpsr_mask = ~(XPSR_SPREALIGN | XPSR_SFPA); + if (!arm_feature(env, ARM_FEATURE_THUMB_DSP)) { + xpsr_mask &= ~XPSR_GE; + } + /* This xpsr_write() will invalidate frame_sp_p as it may switch stack */ + xpsr_write(env, xpsr, xpsr_mask); + + if (env->v7m.secure) { + bool sfpa = xpsr & XPSR_SFPA; + + env->v7m.control[M_REG_S] = FIELD_DP32(env->v7m.control[M_REG_S], + V7M_CONTROL, SFPA, sfpa); + } + + /* + * The restored xPSR exception field will be zero if we're + * resuming in Thread mode. If that doesn't match what the + * exception return excret specified then this is a UsageFault. + * v7M requires we make this check here; v8M did it earlier. + */ + if (return_to_handler != arm_v7m_is_handler_mode(env)) { + /* + * Take an INVPC UsageFault by pushing the stack again; + * we know we're v7M so this is never a Secure UsageFault. + */ + bool ignore_stackfaults; + + assert(!arm_feature(env, ARM_FEATURE_V8)); + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE, false); + env->v7m.cfsr[env->v7m.secure] |= R_V7M_CFSR_INVPC_MASK; + ignore_stackfaults = v7m_push_stack(cpu); + qemu_log_mask(CPU_LOG_INT, "...taking UsageFault on new stackframe: " + "failed exception return integrity check\n"); + v7m_exception_taken(cpu, excret, false, ignore_stackfaults); + return; + } + + /* Otherwise, we have a successful exception exit. */ + arm_clear_exclusive(env); + arm_rebuild_hflags(env); + qemu_log_mask(CPU_LOG_INT, "...successful exception return\n"); +} + +static bool do_v7m_function_return(ARMCPU *cpu) +{ + /* + * v8M security extensions magic function return. + * We may either: + * (1) throw an exception (longjump) + * (2) return true if we successfully handled the function return + * (3) return false if we failed a consistency check and have + * pended a UsageFault that needs to be taken now + * + * At this point the magic return value is split between env->regs[15] + * and env->thumb. We don't bother to reconstitute it because we don't + * need it (all values are handled the same way). + */ + CPUARMState *env = &cpu->env; + uint32_t newpc, newpsr, newpsr_exc; + + qemu_log_mask(CPU_LOG_INT, "...really v7M secure function return\n"); + + { + bool threadmode, spsel; + MemOpIdx oi; + ARMMMUIdx mmu_idx; + uint32_t *frame_sp_p; + uint32_t frameptr; + + /* Pull the return address and IPSR from the Secure stack */ + threadmode = !arm_v7m_is_handler_mode(env); + spsel = env->v7m.control[M_REG_S] & R_V7M_CONTROL_SPSEL_MASK; + + frame_sp_p = get_v7m_sp_ptr(env, true, threadmode, spsel); + frameptr = *frame_sp_p; + + /* + * These loads may throw an exception (for MPU faults). We want to + * do them as secure, so work out what MMU index that is. + */ + mmu_idx = arm_v7m_mmu_idx_for_secstate(env, true); + oi = make_memop_idx(MO_LEUL, arm_to_core_mmu_idx(mmu_idx)); + newpc = cpu_ldl_le_mmu(env, frameptr, oi, 0); + newpsr = cpu_ldl_le_mmu(env, frameptr + 4, oi, 0); + + /* Consistency checks on new IPSR */ + newpsr_exc = newpsr & XPSR_EXCP; + if (!((env->v7m.exception == 0 && newpsr_exc == 0) || + (env->v7m.exception == 1 && newpsr_exc != 0))) { + /* Pend the fault and tell our caller to take it */ + env->v7m.cfsr[env->v7m.secure] |= R_V7M_CFSR_INVPC_MASK; + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE, + env->v7m.secure); + qemu_log_mask(CPU_LOG_INT, + "...taking INVPC UsageFault: " + "IPSR consistency check failed\n"); + return false; + } + + *frame_sp_p = frameptr + 8; + } + + /* This invalidates frame_sp_p */ + switch_v7m_security_state(env, true); + env->v7m.exception = newpsr_exc; + env->v7m.control[M_REG_S] &= ~R_V7M_CONTROL_SFPA_MASK; + if (newpsr & XPSR_SFPA) { + env->v7m.control[M_REG_S] |= R_V7M_CONTROL_SFPA_MASK; + } + xpsr_write(env, 0, XPSR_IT); + env->thumb = newpc & 1; + env->regs[15] = newpc & ~1; + arm_rebuild_hflags(env); + + qemu_log_mask(CPU_LOG_INT, "...function return successful\n"); + return true; +} + +static bool v7m_read_half_insn(ARMCPU *cpu, ARMMMUIdx mmu_idx, bool secure, + uint32_t addr, uint16_t *insn) +{ + /* + * Load a 16-bit portion of a v7M instruction, returning true on success, + * or false on failure (in which case we will have pended the appropriate + * exception). + * We need to do the instruction fetch's MPU and SAU checks + * like this because there is no MMU index that would allow + * doing the load with a single function call. Instead we must + * first check that the security attributes permit the load + * and that they don't mismatch on the two halves of the instruction, + * and then we do the load as a secure load (ie using the security + * attributes of the address, not the CPU, as architecturally required). + */ + CPUState *cs = CPU(cpu); + CPUARMState *env = &cpu->env; + V8M_SAttributes sattrs = {}; + GetPhysAddrResult res = {}; + ARMMMUFaultInfo fi = {}; + MemTxResult txres; + + v8m_security_lookup(env, addr, MMU_INST_FETCH, mmu_idx, secure, &sattrs); + if (!sattrs.nsc || sattrs.ns) { + /* + * This must be the second half of the insn, and it straddles a + * region boundary with the second half not being S&NSC. + */ + env->v7m.sfsr |= R_V7M_SFSR_INVEP_MASK; + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_SECURE, false); + qemu_log_mask(CPU_LOG_INT, + "...really SecureFault with SFSR.INVEP\n"); + return false; + } + if (get_phys_addr(env, addr, MMU_INST_FETCH, mmu_idx, &res, &fi)) { + /* the MPU lookup failed */ + env->v7m.cfsr[env->v7m.secure] |= R_V7M_CFSR_IACCVIOL_MASK; + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_MEM, env->v7m.secure); + qemu_log_mask(CPU_LOG_INT, "...really MemManage with CFSR.IACCVIOL\n"); + return false; + } + *insn = address_space_lduw_le(arm_addressspace(cs, res.f.attrs), + res.f.phys_addr, res.f.attrs, &txres); + if (txres != MEMTX_OK) { + env->v7m.cfsr[M_REG_NS] |= R_V7M_CFSR_IBUSERR_MASK; + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_BUS, false); + qemu_log_mask(CPU_LOG_INT, "...really BusFault with CFSR.IBUSERR\n"); + return false; + } + return true; +} + +static bool v7m_read_sg_stack_word(ARMCPU *cpu, ARMMMUIdx mmu_idx, + uint32_t addr, uint32_t *spdata) +{ + /* + * Read a word of data from the stack for the SG instruction, + * writing the value into *spdata. If the load succeeds, return + * true; otherwise pend an appropriate exception and return false. + * (We can't use data load helpers here that throw an exception + * because of the context we're called in, which is halfway through + * arm_v7m_cpu_do_interrupt().) + */ + CPUState *cs = CPU(cpu); + CPUARMState *env = &cpu->env; + MemTxResult txres; + GetPhysAddrResult res = {}; + ARMMMUFaultInfo fi = {}; + uint32_t value; + + if (get_phys_addr(env, addr, MMU_DATA_LOAD, mmu_idx, &res, &fi)) { + /* MPU/SAU lookup failed */ + if (fi.type == ARMFault_QEMU_SFault) { + qemu_log_mask(CPU_LOG_INT, + "...SecureFault during stack word read\n"); + env->v7m.sfsr |= R_V7M_SFSR_AUVIOL_MASK | R_V7M_SFSR_SFARVALID_MASK; + env->v7m.sfar = addr; + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_SECURE, false); + } else { + qemu_log_mask(CPU_LOG_INT, + "...MemManageFault during stack word read\n"); + env->v7m.cfsr[M_REG_S] |= R_V7M_CFSR_DACCVIOL_MASK | + R_V7M_CFSR_MMARVALID_MASK; + env->v7m.mmfar[M_REG_S] = addr; + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_MEM, false); + } + return false; + } + value = address_space_ldl(arm_addressspace(cs, res.f.attrs), + res.f.phys_addr, res.f.attrs, &txres); + if (txres != MEMTX_OK) { + /* BusFault trying to read the data */ + qemu_log_mask(CPU_LOG_INT, + "...BusFault during stack word read\n"); + env->v7m.cfsr[M_REG_NS] |= + (R_V7M_CFSR_PRECISERR_MASK | R_V7M_CFSR_BFARVALID_MASK); + env->v7m.bfar = addr; + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_BUS, false); + return false; + } + + *spdata = value; + return true; +} + +static bool v7m_handle_execute_nsc(ARMCPU *cpu) +{ + /* + * Check whether this attempt to execute code in a Secure & NS-Callable + * memory region is for an SG instruction; if so, then emulate the + * effect of the SG instruction and return true. Otherwise pend + * the correct kind of exception and return false. + */ + CPUARMState *env = &cpu->env; + ARMMMUIdx mmu_idx; + uint16_t insn; + + /* + * We should never get here unless get_phys_addr_pmsav8() caused + * an exception for NS executing in S&NSC memory. + */ + assert(!env->v7m.secure); + assert(arm_feature(env, ARM_FEATURE_M_SECURITY)); + + /* We want to do the MPU lookup as secure; work out what mmu_idx that is */ + mmu_idx = arm_v7m_mmu_idx_for_secstate(env, true); + + if (!v7m_read_half_insn(cpu, mmu_idx, true, env->regs[15], &insn)) { + return false; + } + + if (!env->thumb) { + goto gen_invep; + } + + if (insn != 0xe97f) { + /* + * Not an SG instruction first half (we choose the IMPDEF + * early-SG-check option). + */ + goto gen_invep; + } + + if (!v7m_read_half_insn(cpu, mmu_idx, true, env->regs[15] + 2, &insn)) { + return false; + } + + if (insn != 0xe97f) { + /* + * Not an SG instruction second half (yes, both halves of the SG + * insn have the same hex value) + */ + goto gen_invep; + } + + /* + * OK, we have confirmed that we really have an SG instruction. + * We know we're NS in S memory so don't need to repeat those checks. + */ + qemu_log_mask(CPU_LOG_INT, "...really an SG instruction at 0x%08" PRIx32 + ", executing it\n", env->regs[15]); + + if (cpu_isar_feature(aa32_m_sec_state, cpu) && + !arm_v7m_is_handler_mode(env)) { + /* + * v8.1M exception stack frame integrity check. Note that we + * must perform the memory access even if CCR_S.TRD is zero + * and we aren't going to check what the data loaded is. + */ + uint32_t spdata, sp; + + /* + * We know we are currently NS, so the S stack pointers must be + * in other_ss_{psp,msp}, not in regs[13]/other_sp. + */ + sp = v7m_using_psp(env) ? env->v7m.other_ss_psp : env->v7m.other_ss_msp; + if (!v7m_read_sg_stack_word(cpu, mmu_idx, sp, &spdata)) { + /* Stack access failed and an exception has been pended */ + return false; + } + + if (env->v7m.ccr[M_REG_S] & R_V7M_CCR_TRD_MASK) { + if (((spdata & ~1) == 0xfefa125a) || + !(env->v7m.control[M_REG_S] & 1)) { + goto gen_invep; + } + } + } + + env->regs[14] &= ~1; + env->v7m.control[M_REG_S] &= ~R_V7M_CONTROL_SFPA_MASK; + switch_v7m_security_state(env, true); + xpsr_write(env, 0, XPSR_IT); + env->regs[15] += 4; + arm_rebuild_hflags(env); + return true; + +gen_invep: + env->v7m.sfsr |= R_V7M_SFSR_INVEP_MASK; + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_SECURE, false); + qemu_log_mask(CPU_LOG_INT, + "...really SecureFault with SFSR.INVEP\n"); + return false; +} + +void arm_v7m_cpu_do_interrupt(CPUState *cs) +{ + ARMCPU *cpu = ARM_CPU(cs); + CPUARMState *env = &cpu->env; + uint32_t lr; + bool ignore_stackfaults; + + arm_log_exception(cs); + + /* + * For exceptions we just mark as pending on the NVIC, and let that + * handle it. + */ + switch (cs->exception_index) { + case EXCP_UDEF: + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE, env->v7m.secure); + env->v7m.cfsr[env->v7m.secure] |= R_V7M_CFSR_UNDEFINSTR_MASK; + break; + case EXCP_NOCP: + { + /* + * NOCP might be directed to something other than the current + * security state if this fault is because of NSACR; we indicate + * the target security state using exception.target_el. + */ + int target_secstate; + + if (env->exception.target_el == 3) { + target_secstate = M_REG_S; + } else { + target_secstate = env->v7m.secure; + } + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE, target_secstate); + env->v7m.cfsr[target_secstate] |= R_V7M_CFSR_NOCP_MASK; + break; + } + case EXCP_INVSTATE: + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE, env->v7m.secure); + env->v7m.cfsr[env->v7m.secure] |= R_V7M_CFSR_INVSTATE_MASK; + break; + case EXCP_STKOF: + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE, env->v7m.secure); + env->v7m.cfsr[env->v7m.secure] |= R_V7M_CFSR_STKOF_MASK; + break; + case EXCP_LSERR: + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_SECURE, false); + env->v7m.sfsr |= R_V7M_SFSR_LSERR_MASK; + break; + case EXCP_UNALIGNED: + /* Unaligned faults reported by M-profile aware code */ + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE, env->v7m.secure); + env->v7m.cfsr[env->v7m.secure] |= R_V7M_CFSR_UNALIGNED_MASK; + break; + case EXCP_DIVBYZERO: + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE, env->v7m.secure); + env->v7m.cfsr[env->v7m.secure] |= R_V7M_CFSR_DIVBYZERO_MASK; + break; + case EXCP_SWI: + /* The PC already points to the next instruction. */ + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_SVC, env->v7m.secure); + break; + case EXCP_PREFETCH_ABORT: + case EXCP_DATA_ABORT: + /* + * Note that for M profile we don't have a guest facing FSR, but + * the env->exception.fsr will be populated by the code that + * raises the fault, in the A profile short-descriptor format. + * + * Log the exception.vaddress now regardless of subtype, because + * logging below only logs it when it goes into a guest visible + * register. + */ + qemu_log_mask(CPU_LOG_INT, "...at fault address 0x%x\n", + (uint32_t)env->exception.vaddress); + switch (env->exception.fsr & 0xf) { + case M_FAKE_FSR_NSC_EXEC: + /* + * Exception generated when we try to execute code at an address + * which is marked as Secure & Non-Secure Callable and the CPU + * is in the Non-Secure state. The only instruction which can + * be executed like this is SG (and that only if both halves of + * the SG instruction have the same security attributes.) + * Everything else must generate an INVEP SecureFault, so we + * emulate the SG instruction here. + */ + if (v7m_handle_execute_nsc(cpu)) { + return; + } + break; + case M_FAKE_FSR_SFAULT: + /* + * Various flavours of SecureFault for attempts to execute or + * access data in the wrong security state. + */ + switch (cs->exception_index) { + case EXCP_PREFETCH_ABORT: + if (env->v7m.secure) { + env->v7m.sfsr |= R_V7M_SFSR_INVTRAN_MASK; + qemu_log_mask(CPU_LOG_INT, + "...really SecureFault with SFSR.INVTRAN\n"); + } else { + env->v7m.sfsr |= R_V7M_SFSR_INVEP_MASK; + qemu_log_mask(CPU_LOG_INT, + "...really SecureFault with SFSR.INVEP\n"); + } + break; + case EXCP_DATA_ABORT: + /* This must be an NS access to S memory */ + env->v7m.sfsr |= R_V7M_SFSR_AUVIOL_MASK; + qemu_log_mask(CPU_LOG_INT, + "...really SecureFault with SFSR.AUVIOL\n"); + break; + } + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_SECURE, false); + break; + case 0x8: /* External Abort */ + switch (cs->exception_index) { + case EXCP_PREFETCH_ABORT: + env->v7m.cfsr[M_REG_NS] |= R_V7M_CFSR_IBUSERR_MASK; + qemu_log_mask(CPU_LOG_INT, "...with CFSR.IBUSERR\n"); + break; + case EXCP_DATA_ABORT: + env->v7m.cfsr[M_REG_NS] |= + (R_V7M_CFSR_PRECISERR_MASK | R_V7M_CFSR_BFARVALID_MASK); + env->v7m.bfar = env->exception.vaddress; + qemu_log_mask(CPU_LOG_INT, + "...with CFSR.PRECISERR and BFAR 0x%x\n", + env->v7m.bfar); + break; + } + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_BUS, false); + break; + case 0x1: /* Alignment fault reported by generic code */ + qemu_log_mask(CPU_LOG_INT, + "...really UsageFault with UFSR.UNALIGNED\n"); + env->v7m.cfsr[env->v7m.secure] |= R_V7M_CFSR_UNALIGNED_MASK; + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE, + env->v7m.secure); + break; + default: + /* + * All other FSR values are either MPU faults or "can't happen + * for M profile" cases. + */ + switch (cs->exception_index) { + case EXCP_PREFETCH_ABORT: + env->v7m.cfsr[env->v7m.secure] |= R_V7M_CFSR_IACCVIOL_MASK; + qemu_log_mask(CPU_LOG_INT, "...with CFSR.IACCVIOL\n"); + break; + case EXCP_DATA_ABORT: + env->v7m.cfsr[env->v7m.secure] |= + (R_V7M_CFSR_DACCVIOL_MASK | R_V7M_CFSR_MMARVALID_MASK); + env->v7m.mmfar[env->v7m.secure] = env->exception.vaddress; + qemu_log_mask(CPU_LOG_INT, + "...with CFSR.DACCVIOL and MMFAR 0x%x\n", + env->v7m.mmfar[env->v7m.secure]); + break; + } + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_MEM, + env->v7m.secure); + break; + } + break; + case EXCP_SEMIHOST: + qemu_log_mask(CPU_LOG_INT, + "...handling as semihosting call 0x%x\n", + env->regs[0]); +#ifdef CONFIG_TCG + do_common_semihosting(cs); +#else + g_assert_not_reached(); +#endif + env->regs[15] += env->thumb ? 2 : 4; + return; + case EXCP_BKPT: + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_DEBUG, false); + break; + case EXCP_IRQ: + break; + case EXCP_EXCEPTION_EXIT: + if (env->regs[15] < EXC_RETURN_MIN_MAGIC) { + /* Must be v8M security extension function return */ + assert(env->regs[15] >= FNC_RETURN_MIN_MAGIC); + assert(arm_feature(env, ARM_FEATURE_M_SECURITY)); + if (do_v7m_function_return(cpu)) { + return; + } + } else { + do_v7m_exception_exit(cpu); + return; + } + break; + case EXCP_LAZYFP: + /* + * We already pended the specific exception in the NVIC in the + * v7m_preserve_fp_state() helper function. + */ + break; + default: + cpu_abort(cs, "Unhandled exception 0x%x\n", cs->exception_index); + return; /* Never happens. Keep compiler happy. */ + } + + if (arm_feature(env, ARM_FEATURE_V8)) { + lr = R_V7M_EXCRET_RES1_MASK | + R_V7M_EXCRET_DCRS_MASK; + /* + * The S bit indicates whether we should return to Secure + * or NonSecure (ie our current state). + * The ES bit indicates whether we're taking this exception + * to Secure or NonSecure (ie our target state). We set it + * later, in v7m_exception_taken(). + * The SPSEL bit is also set in v7m_exception_taken() for v8M. + * This corresponds to the ARM ARM pseudocode for v8M setting + * some LR bits in PushStack() and some in ExceptionTaken(); + * the distinction matters for the tailchain cases where we + * can take an exception without pushing the stack. + */ + if (env->v7m.secure) { + lr |= R_V7M_EXCRET_S_MASK; + } + } else { + lr = R_V7M_EXCRET_RES1_MASK | + R_V7M_EXCRET_S_MASK | + R_V7M_EXCRET_DCRS_MASK | + R_V7M_EXCRET_ES_MASK; + if (env->v7m.control[M_REG_NS] & R_V7M_CONTROL_SPSEL_MASK) { + lr |= R_V7M_EXCRET_SPSEL_MASK; + } + } + if (!(env->v7m.control[M_REG_S] & R_V7M_CONTROL_FPCA_MASK)) { + lr |= R_V7M_EXCRET_FTYPE_MASK; + } + if (!arm_v7m_is_handler_mode(env)) { + lr |= R_V7M_EXCRET_MODE_MASK; + } + + ignore_stackfaults = v7m_push_stack(cpu); + v7m_exception_taken(cpu, lr, false, ignore_stackfaults); +} + +uint32_t HELPER(v7m_mrs)(CPUARMState *env, uint32_t reg) +{ + unsigned el = arm_current_el(env); + + /* First handle registers which unprivileged can read */ + switch (reg) { + case 0 ... 7: /* xPSR sub-fields */ + return v7m_mrs_xpsr(env, reg, el); + case 20: /* CONTROL */ + return v7m_mrs_control(env, env->v7m.secure); + case 0x94: /* CONTROL_NS */ + /* + * We have to handle this here because unprivileged Secure code + * can read the NS CONTROL register. + */ + if (!env->v7m.secure) { + return 0; + } + return env->v7m.control[M_REG_NS] | + (env->v7m.control[M_REG_S] & R_V7M_CONTROL_FPCA_MASK); + } + + if (el == 0) { + return 0; /* unprivileged reads others as zero */ + } + + if (arm_feature(env, ARM_FEATURE_M_SECURITY)) { + switch (reg) { + case 0x88: /* MSP_NS */ + if (!env->v7m.secure) { + return 0; + } + return env->v7m.other_ss_msp; + case 0x89: /* PSP_NS */ + if (!env->v7m.secure) { + return 0; + } + return env->v7m.other_ss_psp; + case 0x8a: /* MSPLIM_NS */ + if (!env->v7m.secure) { + return 0; + } + return env->v7m.msplim[M_REG_NS]; + case 0x8b: /* PSPLIM_NS */ + if (!env->v7m.secure) { + return 0; + } + return env->v7m.psplim[M_REG_NS]; + case 0x90: /* PRIMASK_NS */ + if (!env->v7m.secure) { + return 0; + } + return env->v7m.primask[M_REG_NS]; + case 0x91: /* BASEPRI_NS */ + if (!arm_feature(env, ARM_FEATURE_M_MAIN)) { + goto bad_reg; + } + if (!env->v7m.secure) { + return 0; + } + return env->v7m.basepri[M_REG_NS]; + case 0x93: /* FAULTMASK_NS */ + if (!arm_feature(env, ARM_FEATURE_M_MAIN)) { + goto bad_reg; + } + if (!env->v7m.secure) { + return 0; + } + return env->v7m.faultmask[M_REG_NS]; + case 0x98: /* SP_NS */ + { + /* + * This gives the non-secure SP selected based on whether we're + * currently in handler mode or not, using the NS CONTROL.SPSEL. + */ + bool spsel = env->v7m.control[M_REG_NS] & R_V7M_CONTROL_SPSEL_MASK; + + if (!env->v7m.secure) { + return 0; + } + if (!arm_v7m_is_handler_mode(env) && spsel) { + return env->v7m.other_ss_psp; + } else { + return env->v7m.other_ss_msp; + } + } + default: + break; + } + } + + switch (reg) { + case 8: /* MSP */ + return v7m_using_psp(env) ? env->v7m.other_sp : env->regs[13]; + case 9: /* PSP */ + return v7m_using_psp(env) ? env->regs[13] : env->v7m.other_sp; + case 10: /* MSPLIM */ + if (!arm_feature(env, ARM_FEATURE_V8)) { + goto bad_reg; + } + return env->v7m.msplim[env->v7m.secure]; + case 11: /* PSPLIM */ + if (!arm_feature(env, ARM_FEATURE_V8)) { + goto bad_reg; + } + return env->v7m.psplim[env->v7m.secure]; + case 16: /* PRIMASK */ + return env->v7m.primask[env->v7m.secure]; + case 17: /* BASEPRI */ + case 18: /* BASEPRI_MAX */ + if (!arm_feature(env, ARM_FEATURE_M_MAIN)) { + goto bad_reg; + } + return env->v7m.basepri[env->v7m.secure]; + case 19: /* FAULTMASK */ + if (!arm_feature(env, ARM_FEATURE_M_MAIN)) { + goto bad_reg; + } + return env->v7m.faultmask[env->v7m.secure]; + default: + bad_reg: + qemu_log_mask(LOG_GUEST_ERROR, "Attempt to read unknown special" + " register %d\n", reg); + return 0; + } +} + +void HELPER(v7m_msr)(CPUARMState *env, uint32_t maskreg, uint32_t val) +{ + /* + * We're passed bits [11..0] of the instruction; extract + * SYSm and the mask bits. + * Invalid combinations of SYSm and mask are UNPREDICTABLE; + * we choose to treat them as if the mask bits were valid. + * NB that the pseudocode 'mask' variable is bits [11..10], + * whereas ours is [11..8]. + */ + uint32_t mask = extract32(maskreg, 8, 4); + uint32_t reg = extract32(maskreg, 0, 8); + int cur_el = arm_current_el(env); + + if (cur_el == 0 && reg > 7 && reg != 20) { + /* + * only xPSR sub-fields and CONTROL.SFPA may be written by + * unprivileged code + */ + return; + } + + if (arm_feature(env, ARM_FEATURE_M_SECURITY)) { + switch (reg) { + case 0x88: /* MSP_NS */ + if (!env->v7m.secure) { + return; + } + env->v7m.other_ss_msp = val & ~3; + return; + case 0x89: /* PSP_NS */ + if (!env->v7m.secure) { + return; + } + env->v7m.other_ss_psp = val & ~3; + return; + case 0x8a: /* MSPLIM_NS */ + if (!env->v7m.secure) { + return; + } + env->v7m.msplim[M_REG_NS] = val & ~7; + return; + case 0x8b: /* PSPLIM_NS */ + if (!env->v7m.secure) { + return; + } + env->v7m.psplim[M_REG_NS] = val & ~7; + return; + case 0x90: /* PRIMASK_NS */ + if (!env->v7m.secure) { + return; + } + env->v7m.primask[M_REG_NS] = val & 1; + return; + case 0x91: /* BASEPRI_NS */ + if (!arm_feature(env, ARM_FEATURE_M_MAIN)) { + goto bad_reg; + } + if (!env->v7m.secure) { + return; + } + env->v7m.basepri[M_REG_NS] = val & 0xff; + return; + case 0x93: /* FAULTMASK_NS */ + if (!arm_feature(env, ARM_FEATURE_M_MAIN)) { + goto bad_reg; + } + if (!env->v7m.secure) { + return; + } + env->v7m.faultmask[M_REG_NS] = val & 1; + return; + case 0x94: /* CONTROL_NS */ + if (!env->v7m.secure) { + return; + } + write_v7m_control_spsel_for_secstate(env, + val & R_V7M_CONTROL_SPSEL_MASK, + M_REG_NS); + if (arm_feature(env, ARM_FEATURE_M_MAIN)) { + env->v7m.control[M_REG_NS] &= ~R_V7M_CONTROL_NPRIV_MASK; + env->v7m.control[M_REG_NS] |= val & R_V7M_CONTROL_NPRIV_MASK; + } + /* + * SFPA is RAZ/WI from NS. FPCA is RO if NSACR.CP10 == 0, + * RES0 if the FPU is not present, and is stored in the S bank + */ + if (cpu_isar_feature(aa32_vfp_simd, env_archcpu(env)) && + extract32(env->v7m.nsacr, 10, 1)) { + env->v7m.control[M_REG_S] &= ~R_V7M_CONTROL_FPCA_MASK; + env->v7m.control[M_REG_S] |= val & R_V7M_CONTROL_FPCA_MASK; + } + return; + case 0x98: /* SP_NS */ + { + /* + * This gives the non-secure SP selected based on whether we're + * currently in handler mode or not, using the NS CONTROL.SPSEL. + */ + bool spsel = env->v7m.control[M_REG_NS] & R_V7M_CONTROL_SPSEL_MASK; + bool is_psp = !arm_v7m_is_handler_mode(env) && spsel; + uint32_t limit; + + if (!env->v7m.secure) { + return; + } + + limit = is_psp ? env->v7m.psplim[false] : env->v7m.msplim[false]; + + val &= ~0x3; + + if (val < limit) { + raise_exception_ra(env, EXCP_STKOF, 0, 1, GETPC()); + } + + if (is_psp) { + env->v7m.other_ss_psp = val; + } else { + env->v7m.other_ss_msp = val; + } + return; + } + default: + break; + } + } + + switch (reg) { + case 0 ... 7: /* xPSR sub-fields */ + v7m_msr_xpsr(env, mask, reg, val); + break; + case 8: /* MSP */ + if (v7m_using_psp(env)) { + env->v7m.other_sp = val & ~3; + } else { + env->regs[13] = val & ~3; + } + break; + case 9: /* PSP */ + if (v7m_using_psp(env)) { + env->regs[13] = val & ~3; + } else { + env->v7m.other_sp = val & ~3; + } + break; + case 10: /* MSPLIM */ + if (!arm_feature(env, ARM_FEATURE_V8)) { + goto bad_reg; + } + env->v7m.msplim[env->v7m.secure] = val & ~7; + break; + case 11: /* PSPLIM */ + if (!arm_feature(env, ARM_FEATURE_V8)) { + goto bad_reg; + } + env->v7m.psplim[env->v7m.secure] = val & ~7; + break; + case 16: /* PRIMASK */ + env->v7m.primask[env->v7m.secure] = val & 1; + break; + case 17: /* BASEPRI */ + if (!arm_feature(env, ARM_FEATURE_M_MAIN)) { + goto bad_reg; + } + env->v7m.basepri[env->v7m.secure] = val & 0xff; + break; + case 18: /* BASEPRI_MAX */ + if (!arm_feature(env, ARM_FEATURE_M_MAIN)) { + goto bad_reg; + } + val &= 0xff; + if (val != 0 && (val < env->v7m.basepri[env->v7m.secure] + || env->v7m.basepri[env->v7m.secure] == 0)) { + env->v7m.basepri[env->v7m.secure] = val; + } + break; + case 19: /* FAULTMASK */ + if (!arm_feature(env, ARM_FEATURE_M_MAIN)) { + goto bad_reg; + } + env->v7m.faultmask[env->v7m.secure] = val & 1; + break; + case 20: /* CONTROL */ + /* + * Writing to the SPSEL bit only has an effect if we are in + * thread mode; other bits can be updated by any privileged code. + * write_v7m_control_spsel() deals with updating the SPSEL bit in + * env->v7m.control, so we only need update the others. + * For v7M, we must just ignore explicit writes to SPSEL in handler + * mode; for v8M the write is permitted but will have no effect. + * All these bits are writes-ignored from non-privileged code, + * except for SFPA. + */ + if (cur_el > 0 && (arm_feature(env, ARM_FEATURE_V8) || + !arm_v7m_is_handler_mode(env))) { + write_v7m_control_spsel(env, (val & R_V7M_CONTROL_SPSEL_MASK) != 0); + } + if (cur_el > 0 && arm_feature(env, ARM_FEATURE_M_MAIN)) { + env->v7m.control[env->v7m.secure] &= ~R_V7M_CONTROL_NPRIV_MASK; + env->v7m.control[env->v7m.secure] |= val & R_V7M_CONTROL_NPRIV_MASK; + } + if (cpu_isar_feature(aa32_vfp_simd, env_archcpu(env))) { + /* + * SFPA is RAZ/WI from NS or if no FPU. + * FPCA is RO if NSACR.CP10 == 0, RES0 if the FPU is not present. + * Both are stored in the S bank. + */ + if (env->v7m.secure) { + env->v7m.control[M_REG_S] &= ~R_V7M_CONTROL_SFPA_MASK; + env->v7m.control[M_REG_S] |= val & R_V7M_CONTROL_SFPA_MASK; + } + if (cur_el > 0 && + (env->v7m.secure || !arm_feature(env, ARM_FEATURE_M_SECURITY) || + extract32(env->v7m.nsacr, 10, 1))) { + env->v7m.control[M_REG_S] &= ~R_V7M_CONTROL_FPCA_MASK; + env->v7m.control[M_REG_S] |= val & R_V7M_CONTROL_FPCA_MASK; + } + } + break; + default: + bad_reg: + qemu_log_mask(LOG_GUEST_ERROR, "Attempt to write unknown special" + " register %d\n", reg); + return; + } +} + +uint32_t HELPER(v7m_tt)(CPUARMState *env, uint32_t addr, uint32_t op) +{ + /* Implement the TT instruction. op is bits [7:6] of the insn. */ + bool forceunpriv = op & 1; + bool alt = op & 2; + V8M_SAttributes sattrs = {}; + uint32_t tt_resp; + bool r, rw, nsr, nsrw, mrvalid; + ARMMMUIdx mmu_idx; + uint32_t mregion; + bool targetpriv; + bool targetsec = env->v7m.secure; + + /* + * Work out what the security state and privilege level we're + * interested in is... + */ + if (alt) { + targetsec = !targetsec; + } + + if (forceunpriv) { + targetpriv = false; + } else { + targetpriv = arm_v7m_is_handler_mode(env) || + !(env->v7m.control[targetsec] & R_V7M_CONTROL_NPRIV_MASK); + } + + /* ...and then figure out which MMU index this is */ + mmu_idx = arm_v7m_mmu_idx_for_secstate_and_priv(env, targetsec, targetpriv); + + /* + * We know that the MPU and SAU don't care about the access type + * for our purposes beyond that we don't want to claim to be + * an insn fetch, so we arbitrarily call this a read. + */ + + /* + * MPU region info only available for privileged or if + * inspecting the other MPU state. + */ + if (arm_current_el(env) != 0 || alt) { + GetPhysAddrResult res = {}; + ARMMMUFaultInfo fi = {}; + + /* We can ignore the return value as prot is always set */ + pmsav8_mpu_lookup(env, addr, MMU_DATA_LOAD, mmu_idx, targetsec, + &res, &fi, &mregion); + if (mregion == -1) { + mrvalid = false; + mregion = 0; + } else { + mrvalid = true; + } + r = res.f.prot & PAGE_READ; + rw = res.f.prot & PAGE_WRITE; + } else { + r = false; + rw = false; + mrvalid = false; + mregion = 0; + } + + if (env->v7m.secure) { + v8m_security_lookup(env, addr, MMU_DATA_LOAD, mmu_idx, + targetsec, &sattrs); + nsr = sattrs.ns && r; + nsrw = sattrs.ns && rw; + } else { + sattrs.ns = true; + nsr = false; + nsrw = false; + } + + tt_resp = (sattrs.iregion << 24) | + (sattrs.irvalid << 23) | + ((!sattrs.ns) << 22) | + (nsrw << 21) | + (nsr << 20) | + (rw << 19) | + (r << 18) | + (sattrs.srvalid << 17) | + (mrvalid << 16) | + (sattrs.sregion << 8) | + mregion; + + return tt_resp; +} + +#endif /* !CONFIG_USER_ONLY */ |