diff options
Diffstat (limited to 'target')
| -rw-r--r-- | target/arm/cpu.c | 27 | ||||
| -rw-r--r-- | target/arm/cpu.h | 60 | ||||
| -rw-r--r-- | target/arm/helper.c | 691 | ||||
| -rw-r--r-- | target/arm/internals.h | 15 | ||||
| -rw-r--r-- | target/arm/machine.c | 16 | ||||
| -rw-r--r-- | target/arm/op_helper.c | 27 |
6 files changed, 733 insertions, 103 deletions
diff --git a/target/arm/cpu.c b/target/arm/cpu.c index 4300de66e2..f4f601f079 100644 --- a/target/arm/cpu.c +++ b/target/arm/cpu.c @@ -285,6 +285,18 @@ static void arm_cpu_reset(CPUState *s) env->pmsav8.mair1[M_REG_S] = 0; } + if (arm_feature(env, ARM_FEATURE_M_SECURITY)) { + if (cpu->sau_sregion > 0) { + memset(env->sau.rbar, 0, sizeof(*env->sau.rbar) * cpu->sau_sregion); + memset(env->sau.rlar, 0, sizeof(*env->sau.rlar) * cpu->sau_sregion); + } + env->sau.rnr = 0; + /* SAU_CTRL reset value is IMPDEF; we choose 0, which is what + * the Cortex-M33 does. + */ + env->sau.ctrl = 0; + } + set_flush_to_zero(1, &env->vfp.standard_fp_status); set_flush_inputs_to_zero(1, &env->vfp.standard_fp_status); set_default_nan_mode(1, &env->vfp.standard_fp_status); @@ -873,6 +885,20 @@ static void arm_cpu_realizefn(DeviceState *dev, Error **errp) } } + if (arm_feature(env, ARM_FEATURE_M_SECURITY)) { + uint32_t nr = cpu->sau_sregion; + + if (nr > 0xff) { + error_setg(errp, "v8M SAU #regions invalid %" PRIu32, nr); + return; + } + + if (nr) { + env->sau.rbar = g_new0(uint32_t, nr); + env->sau.rlar = g_new0(uint32_t, nr); + } + } + if (arm_feature(env, ARM_FEATURE_EL3)) { set_feature(env, ARM_FEATURE_VBAR); } @@ -1141,6 +1167,7 @@ static void cortex_m4_initfn(Object *obj) cpu->midr = 0x410fc240; /* r0p0 */ cpu->pmsav7_dregion = 8; } + static void arm_v7m_class_init(ObjectClass *oc, void *data) { CPUClass *cc = CPU_CLASS(oc); diff --git a/target/arm/cpu.h b/target/arm/cpu.h index 8afceca873..89d49cdcb2 100644 --- a/target/arm/cpu.h +++ b/target/arm/cpu.h @@ -443,8 +443,10 @@ typedef struct CPUARMState { uint32_t cfsr[M_REG_NUM_BANKS]; /* Configurable Fault Status */ uint32_t hfsr; /* HardFault Status */ uint32_t dfsr; /* Debug Fault Status Register */ + uint32_t sfsr; /* Secure Fault Status Register */ uint32_t mmfar[M_REG_NUM_BANKS]; /* MemManage Fault Address */ uint32_t bfar; /* BusFault Address */ + uint32_t sfar; /* Secure Fault Address Register */ unsigned mpu_ctrl[M_REG_NUM_BANKS]; /* MPU_CTRL */ int exception; uint32_t primask[M_REG_NUM_BANKS]; @@ -566,6 +568,14 @@ typedef struct CPUARMState { uint32_t mair1[M_REG_NUM_BANKS]; } pmsav8; + /* v8M SAU */ + struct { + uint32_t *rbar; + uint32_t *rlar; + uint32_t rnr; + uint32_t ctrl; + } sau; + void *nvic; const struct arm_boot_info *boot_info; /* Store GICv3CPUState to access from this struct */ @@ -661,6 +671,8 @@ struct ARMCPU { bool has_mpu; /* PMSAv7 MPU number of supported regions */ uint32_t pmsav7_dregion; + /* v8M SAU number of supported regions */ + uint32_t sau_sregion; /* PSCI conduit used to invoke PSCI methods * 0 - disabled, 1 - smc, 2 - hvc @@ -991,6 +1003,11 @@ void pmccntr_sync(CPUARMState *env); #define PSTATE_MODE_EL1t 4 #define PSTATE_MODE_EL0t 0 +/* 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. + */ +void write_v7m_exception(CPUARMState *env, uint32_t new_exc); + /* Map EL and handler into a PSTATE_MODE. */ static inline unsigned int aarch64_pstate_mode(unsigned int el, bool handler) { @@ -1071,7 +1088,8 @@ static inline void xpsr_write(CPUARMState *env, uint32_t val, uint32_t mask) env->condexec_bits |= (val >> 8) & 0xfc; } if (mask & XPSR_EXCP) { - env->v7m.exception = val & XPSR_EXCP; + /* Note that this only happens on exception exit */ + write_v7m_exception(env, val & XPSR_EXCP); } } @@ -1254,6 +1272,16 @@ FIELD(V7M_DFSR, DWTTRAP, 2, 1) FIELD(V7M_DFSR, VCATCH, 3, 1) FIELD(V7M_DFSR, EXTERNAL, 4, 1) +/* V7M SFSR bits */ +FIELD(V7M_SFSR, INVEP, 0, 1) +FIELD(V7M_SFSR, INVIS, 1, 1) +FIELD(V7M_SFSR, INVER, 2, 1) +FIELD(V7M_SFSR, AUVIOL, 3, 1) +FIELD(V7M_SFSR, INVTRAN, 4, 1) +FIELD(V7M_SFSR, LSPERR, 5, 1) +FIELD(V7M_SFSR, SFARVALID, 6, 1) +FIELD(V7M_SFSR, LSERR, 7, 1) + /* v7M MPU_CTRL bits */ FIELD(V7M_MPU_CTRL, ENABLE, 0, 1) FIELD(V7M_MPU_CTRL, HFNMIENA, 1, 1) @@ -2301,21 +2329,33 @@ static inline int arm_mmu_idx_to_el(ARMMMUIdx mmu_idx) } } +/* Return the MMU index for a v7M CPU in the specified security state */ +static inline ARMMMUIdx arm_v7m_mmu_idx_for_secstate(CPUARMState *env, + bool secstate) +{ + int el = arm_current_el(env); + ARMMMUIdx mmu_idx; + + if (el == 0) { + mmu_idx = secstate ? ARMMMUIdx_MSUser : ARMMMUIdx_MUser; + } else { + mmu_idx = secstate ? ARMMMUIdx_MSPriv : ARMMMUIdx_MPriv; + } + + if (armv7m_nvic_neg_prio_requested(env->nvic, secstate)) { + mmu_idx = secstate ? ARMMMUIdx_MSNegPri : ARMMMUIdx_MNegPri; + } + + return mmu_idx; +} + /* Determine the current mmu_idx to use for normal loads/stores */ static inline int cpu_mmu_index(CPUARMState *env, bool ifetch) { int el = arm_current_el(env); if (arm_feature(env, ARM_FEATURE_M)) { - ARMMMUIdx mmu_idx = el == 0 ? ARMMMUIdx_MUser : ARMMMUIdx_MPriv; - - if (armv7m_nvic_neg_prio_requested(env->nvic, env->v7m.secure)) { - mmu_idx = ARMMMUIdx_MNegPri; - } - - if (env->v7m.secure) { - mmu_idx += ARMMMUIdx_MSUser; - } + ARMMMUIdx mmu_idx = arm_v7m_mmu_idx_for_secstate(env, env->v7m.secure); return arm_to_core_mmu_idx(mmu_idx); } diff --git a/target/arm/helper.c b/target/arm/helper.c index 8be78ea2f8..1d689f00b3 100644 --- a/target/arm/helper.c +++ b/target/arm/helper.c @@ -31,6 +31,16 @@ static bool get_phys_addr_lpae(CPUARMState *env, target_ulong address, target_ulong *page_size_ptr, uint32_t *fsr, ARMMMUFaultInfo *fi); +/* Security attributes for an address, as returned by v8m_security_lookup. */ +typedef struct V8M_SAttributes { + bool ns; + bool nsc; + uint8_t sregion; + bool srvalid; + uint8_t iregion; + bool irvalid; +} V8M_SAttributes; + /* Definitions for the PMCCNTR and PMCR registers */ #define PMCRD 0x8 #define PMCRC 0x4 @@ -3717,7 +3727,14 @@ static void hcr_write(CPUARMState *env, const ARMCPRegInfo *ri, uint64_t value) if (arm_feature(env, ARM_FEATURE_EL3)) { valid_mask &= ~HCR_HCD; - } else { + } else if (cpu->psci_conduit != QEMU_PSCI_CONDUIT_SMC) { + /* Architecturally HCR.TSC is RES0 if EL3 is not implemented. + * However, if we're using the SMC PSCI conduit then QEMU is + * effectively acting like EL3 firmware and so the guest at + * EL2 should retain the ability to prevent EL1 from being + * able to make SMC calls into the ersatz firmware, so in + * that case HCR.TSC should be read/write. + */ valid_mask &= ~HCR_TSC; } @@ -6040,16 +6057,6 @@ static void v7m_push(CPUARMState *env, uint32_t val) stl_phys(cs->as, env->regs[13], val); } -static uint32_t v7m_pop(CPUARMState *env) -{ - CPUState *cs = CPU(arm_env_get_cpu(env)); - uint32_t val; - - val = ldl_phys(cs->as, env->regs[13]); - env->regs[13] += 4; - return val; -} - /* Return true if we're using the process stack pointer (not the MSP) */ static bool v7m_using_psp(CPUARMState *env) { @@ -6062,21 +6069,58 @@ static bool v7m_using_psp(CPUARMState *env) env->v7m.control[env->v7m.secure] & R_V7M_CONTROL_SPSEL_MASK; } -/* Switch to V7M main or process stack pointer. */ -static void switch_v7m_sp(CPUARMState *env, bool new_spsel) +/* 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; - uint32_t old_control = env->v7m.control[env->v7m.secure]; - bool old_spsel = old_control & R_V7M_CONTROL_SPSEL_MASK; - if (old_spsel != new_spsel) { + 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; - - env->v7m.control[env->v7m.secure] = deposit32(old_control, - R_V7M_CONTROL_SPSEL_SHIFT, - R_V7M_CONTROL_SPSEL_LENGTH, new_spsel); } } @@ -6141,12 +6185,47 @@ void HELPER(v7m_bxns)(CPUARMState *env, uint32_t dest) env->regs[15] = dest & ~1; } -static uint32_t arm_v7m_load_vector(ARMCPU *cpu) +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 uint32_t arm_v7m_load_vector(ARMCPU *cpu, bool targets_secure) { CPUState *cs = CPU(cpu); CPUARMState *env = &cpu->env; MemTxResult result; - hwaddr vec = env->v7m.vecbase[env->v7m.secure] + env->v7m.exception * 4; + hwaddr vec = env->v7m.vecbase[targets_secure] + env->v7m.exception * 4; uint32_t addr; addr = address_space_ldl(cs->as, vec, @@ -6158,13 +6237,48 @@ static uint32_t arm_v7m_load_vector(ARMCPU *cpu) * Since we don't model Lockup, we just report this guest error * via cpu_abort(). */ - cpu_abort(cs, "Failed to read from exception vector table " - "entry %08x\n", (unsigned)vec); + cpu_abort(cs, "Failed to read from %s exception vector table " + "entry %08x\n", targets_secure ? "secure" : "nonsecure", + (unsigned)vec); } return addr; } -static void v7m_exception_taken(ARMCPU *cpu, uint32_t lr) +static void v7m_push_callee_stack(ARMCPU *cpu, uint32_t lr, bool dotailchain) +{ + /* 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; + CPUState *cs = CPU(cpu); + uint32_t *frame_sp_p; + uint32_t frameptr; + + if (dotailchain) { + frame_sp_p = get_v7m_sp_ptr(env, true, + lr & R_V7M_EXCRET_MODE_MASK, + lr & R_V7M_EXCRET_SPSEL_MASK); + } else { + frame_sp_p = &env->regs[13]; + } + + frameptr = *frame_sp_p - 0x28; + + stl_phys(cs->as, frameptr, 0xfefa125b); + stl_phys(cs->as, frameptr + 0x8, env->regs[4]); + stl_phys(cs->as, frameptr + 0xc, env->regs[5]); + stl_phys(cs->as, frameptr + 0x10, env->regs[6]); + stl_phys(cs->as, frameptr + 0x14, env->regs[7]); + stl_phys(cs->as, frameptr + 0x18, env->regs[8]); + stl_phys(cs->as, frameptr + 0x1c, env->regs[9]); + stl_phys(cs->as, frameptr + 0x20, env->regs[10]); + stl_phys(cs->as, frameptr + 0x24, env->regs[11]); + + *frame_sp_p = frameptr; +} + +static void v7m_exception_taken(ARMCPU *cpu, uint32_t lr, bool dotailchain) { /* Do the "take the exception" parts of exception entry, * but not the pushing of state to the stack. This is @@ -6172,14 +6286,84 @@ static void v7m_exception_taken(ARMCPU *cpu, uint32_t lr) */ CPUARMState *env = &cpu->env; uint32_t addr; + bool targets_secure; + + targets_secure = armv7m_nvic_acknowledge_irq(env->nvic); + + 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))) { + v7m_push_callee_stack(cpu, lr, dotailchain); + } + lr |= R_V7M_EXCRET_DCRS_MASK; + } + } - armv7m_nvic_acknowledge_irq(env->nvic); - switch_v7m_sp(env, 0); + lr &= ~R_V7M_EXCRET_ES_MASK; + if (targets_secure || !arm_feature(env, ARM_FEATURE_M_SECURITY)) { + 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. + */ + if (arm_feature(env, ARM_FEATURE_M_SECURITY)) { + if (!targets_secure) { + /* 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; + + for (i = 0; i < 13; i++) { + /* r4..r11 are callee-saves, zero only if EXCRET.S == 1 */ + if (i < 4 || i > 11 || (lr & R_V7M_EXCRET_S_MASK)) { + env->regs[i] = 0; + } + } + /* Clear EAPSR */ + xpsr_write(env, 0, XPSR_NZCV | XPSR_Q | XPSR_GE | XPSR_IT); + } + } + } + + /* 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 IT bits */ env->condexec_bits = 0; env->regs[14] = lr; - addr = arm_v7m_load_vector(cpu); + addr = arm_v7m_load_vector(cpu, targets_secure); env->regs[15] = addr & 0xfffffffe; env->thumb = addr & 1; } @@ -6212,13 +6396,16 @@ static void v7m_push_stack(ARMCPU *cpu) static void do_v7m_exception_exit(ARMCPU *cpu) { CPUARMState *env = &cpu->env; + CPUState *cs = CPU(cpu); uint32_t excret; uint32_t xpsr; bool ufault = false; - bool return_to_sp_process = false; - bool return_to_handler = false; + bool sfault = false; + bool return_to_sp_process; + bool return_to_handler; bool rettobase = false; bool exc_secure = false; + bool return_to_secure; /* We can only get here from an EXCP_EXCEPTION_EXIT, and * gen_bx_excret() enforces the architectural rule @@ -6249,6 +6436,19 @@ static void do_v7m_exception_exit(ARMCPU *cpu) excret); } + 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; + } + } + 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 @@ -6286,21 +6486,53 @@ static void do_v7m_exception_exit(ARMCPU *cpu) g_assert_not_reached(); } - switch (excret & 0xf) { - case 1: /* Return to Handler */ - return_to_handler = true; - break; - case 13: /* Return to Thread using Process stack */ - return_to_sp_process = true; - /* fall through */ - case 9: /* Return to Thread using Main stack */ - if (!rettobase && - !(env->v7m.ccr[env->v7m.secure] & R_V7M_CCR_NONBASETHRDENA_MASK)) { + 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; } - break; - default: - 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; + } + } + + if (sfault) { + env->v7m.sfsr |= R_V7M_SFSR_INVER_MASK; + armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_SECURE, false); + v7m_exception_taken(cpu, excret, true); + qemu_log_mask(CPU_LOG_INT, "...taking SecureFault on existing " + "stackframe: failed EXC_RETURN.ES validity check\n"); + return; } if (ufault) { @@ -6309,52 +6541,157 @@ static void do_v7m_exception_exit(ARMCPU *cpu) */ env->v7m.cfsr[env->v7m.secure] |= R_V7M_CFSR_INVPC_MASK; armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE, env->v7m.secure); - v7m_exception_taken(cpu, excret); + v7m_exception_taken(cpu, excret, true); qemu_log_mask(CPU_LOG_INT, "...taking UsageFault on existing " "stackframe: failed exception return integrity check\n"); return; } - /* Switch to the target stack. */ - switch_v7m_sp(env, return_to_sp_process); - /* Pop registers. */ - env->regs[0] = v7m_pop(env); - env->regs[1] = v7m_pop(env); - env->regs[2] = v7m_pop(env); - env->regs[3] = v7m_pop(env); - env->regs[12] = v7m_pop(env); - env->regs[14] = v7m_pop(env); - env->regs[15] = v7m_pop(env); - if (env->regs[15] & 1) { - qemu_log_mask(LOG_GUEST_ERROR, - "M profile return from interrupt with misaligned " - "PC is UNPREDICTABLE\n"); - /* Actual 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. + /* 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. + */ + write_v7m_control_spsel_for_secstate(env, return_to_sp_process, exc_secure); + + 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. + */ + uint32_t *frame_sp_p = get_v7m_sp_ptr(env, + return_to_secure, + !return_to_handler, + return_to_sp_process); + uint32_t frameptr = *frame_sp_p; + + 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 expected_sig = 0xfefa125b; + uint32_t actual_sig = ldl_phys(cs->as, frameptr); + + if (expected_sig != 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); + v7m_exception_taken(cpu, excret, true); + qemu_log_mask(CPU_LOG_INT, "...taking SecureFault on existing " + "stackframe: failed exception return integrity " + "signature check\n"); + return; + } + + env->regs[4] = ldl_phys(cs->as, frameptr + 0x8); + env->regs[5] = ldl_phys(cs->as, frameptr + 0xc); + env->regs[6] = ldl_phys(cs->as, frameptr + 0x10); + env->regs[7] = ldl_phys(cs->as, frameptr + 0x14); + env->regs[8] = ldl_phys(cs->as, frameptr + 0x18); + env->regs[9] = ldl_phys(cs->as, frameptr + 0x1c); + env->regs[10] = ldl_phys(cs->as, frameptr + 0x20); + env->regs[11] = ldl_phys(cs->as, frameptr + 0x24); + + frameptr += 0x28; + } + + /* Pop registers. TODO: make these accesses use the correct + * attributes and address space (S/NS, priv/unpriv) and handle + * memory transaction failures. */ - env->regs[15] &= ~1U; + env->regs[0] = ldl_phys(cs->as, frameptr); + env->regs[1] = ldl_phys(cs->as, frameptr + 0x4); + env->regs[2] = ldl_phys(cs->as, frameptr + 0x8); + env->regs[3] = ldl_phys(cs->as, frameptr + 0xc); + env->regs[12] = ldl_phys(cs->as, frameptr + 0x10); + env->regs[14] = ldl_phys(cs->as, frameptr + 0x14); + env->regs[15] = ldl_phys(cs->as, frameptr + 0x18); + + /* 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"); + } + } + + xpsr = ldl_phys(cs->as, frameptr + 0x1c); + + 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; + v7m_exception_taken(cpu, excret, true); + qemu_log_mask(CPU_LOG_INT, "...taking UsageFault on existing " + "stackframe: failed exception return integrity " + "check\n"); + return; + } + } + + /* Commit to consuming the stack frame */ + frameptr += 0x20; + /* 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 = v7m_pop(env); + /* This xpsr_write() will invalidate frame_sp_p as it may switch stack */ xpsr_write(env, xpsr, ~XPSR_SPREALIGN); - /* Undo stack alignment. */ - if (xpsr & XPSR_SPREALIGN) { - env->regs[13] |= 4; - } /* 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. - * TODO: the v8M version of this code should target the - * background state for this exception. + /* Take an INVPC UsageFault by pushing the stack again; + * we know we're v7M so this is never a Secure UsageFault. */ + 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; v7m_push_stack(cpu); - v7m_exception_taken(cpu, excret); + v7m_exception_taken(cpu, excret, false); qemu_log_mask(CPU_LOG_INT, "...taking UsageFault on new stackframe: " "failed exception return integrity check\n"); return; @@ -6433,6 +6770,46 @@ void arm_v7m_cpu_do_interrupt(CPUState *cs) * raises the fault, in the A profile short-descriptor format. */ 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. + * TODO: actually emulate SG. + */ + 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"); + 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: @@ -6498,20 +6875,40 @@ void arm_v7m_cpu_do_interrupt(CPUState *cs) return; /* Never happens. Keep compiler happy. */ } - lr = R_V7M_EXCRET_RES1_MASK | - R_V7M_EXCRET_S_MASK | - R_V7M_EXCRET_DCRS_MASK | - R_V7M_EXCRET_FTYPE_MASK | - R_V7M_EXCRET_ES_MASK; - if (env->v7m.control[env->v7m.secure] & R_V7M_CONTROL_SPSEL_MASK) { - lr |= R_V7M_EXCRET_SPSEL_MASK; + if (arm_feature(env, ARM_FEATURE_V8)) { + lr = R_V7M_EXCRET_RES1_MASK | + R_V7M_EXCRET_DCRS_MASK | + R_V7M_EXCRET_FTYPE_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_FTYPE_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 (!arm_v7m_is_handler_mode(env)) { lr |= R_V7M_EXCRET_MODE_MASK; } v7m_push_stack(cpu); - v7m_exception_taken(cpu, lr); + v7m_exception_taken(cpu, lr, false); qemu_log_mask(CPU_LOG_INT, "... as %d\n", env->v7m.exception); } @@ -8499,9 +8896,89 @@ static bool get_phys_addr_pmsav7(CPUARMState *env, uint32_t address, return !(*prot & (1 << access_type)); } +static bool v8m_is_sau_exempt(CPUARMState *env, + uint32_t address, MMUAccessType access_type) +{ + /* The architecture specifies that certain address ranges are + * exempt from v8M SAU/IDAU checks. + */ + return + (access_type == MMU_INST_FETCH && m_is_system_region(env, address)) || + (address >= 0xe0000000 && address <= 0xe0002fff) || + (address >= 0xe000e000 && address <= 0xe000efff) || + (address >= 0xe002e000 && address <= 0xe002efff) || + (address >= 0xe0040000 && address <= 0xe0041fff) || + (address >= 0xe00ff000 && address <= 0xe00fffff); +} + +static void v8m_security_lookup(CPUARMState *env, uint32_t address, + MMUAccessType access_type, ARMMMUIdx mmu_idx, + V8M_SAttributes *sattrs) +{ + /* Look up the security attributes for this address. Compare the + * pseudocode SecurityCheck() function. + * We assume the caller has zero-initialized *sattrs. + */ + ARMCPU *cpu = arm_env_get_cpu(env); + int r; + + /* TODO: implement IDAU */ + + if (access_type == MMU_INST_FETCH && extract32(address, 28, 4) == 0xf) { + /* 0xf0000000..0xffffffff is always S for insn fetches */ + return; + } + + if (v8m_is_sau_exempt(env, address, access_type)) { + sattrs->ns = !regime_is_secure(env, mmu_idx); + return; + } + + switch (env->sau.ctrl & 3) { + case 0: /* SAU.ENABLE == 0, SAU.ALLNS == 0 */ + break; + case 2: /* SAU.ENABLE == 0, SAU.ALLNS == 1 */ + sattrs->ns = true; + break; + default: /* SAU.ENABLE == 1 */ + for (r = 0; r < cpu->sau_sregion; r++) { + if (env->sau.rlar[r] & 1) { + uint32_t base = env->sau.rbar[r] & ~0x1f; + uint32_t limit = env->sau.rlar[r] | 0x1f; + + if (base <= address && limit >= address) { + if (sattrs->srvalid) { + /* If we hit in more than one region then we must report + * as Secure, not NS-Callable, with no valid region + * number info. + */ + sattrs->ns = false; + sattrs->nsc = false; + sattrs->sregion = 0; + sattrs->srvalid = false; + break; + } else { + if (env->sau.rlar[r] & 2) { + sattrs->nsc = true; + } else { + sattrs->ns = true; + } + sattrs->srvalid = true; + sattrs->sregion = r; + } + } + } + } + + /* TODO when we support the IDAU then it may override the result here */ + break; + } +} + static bool get_phys_addr_pmsav8(CPUARMState *env, uint32_t address, MMUAccessType access_type, ARMMMUIdx mmu_idx, - hwaddr *phys_ptr, int *prot, uint32_t *fsr) + hwaddr *phys_ptr, MemTxAttrs *txattrs, + int *prot, uint32_t *fsr) { ARMCPU *cpu = arm_env_get_cpu(env); bool is_user = regime_is_user(env, mmu_idx); @@ -8509,10 +8986,58 @@ static bool get_phys_addr_pmsav8(CPUARMState *env, uint32_t address, int n; int matchregion = -1; bool hit = false; + V8M_SAttributes sattrs = {}; *phys_ptr = address; *prot = 0; + if (arm_feature(env, ARM_FEATURE_M_SECURITY)) { + v8m_security_lookup(env, address, access_type, mmu_idx, &sattrs); + if (access_type == MMU_INST_FETCH) { + /* Instruction fetches always use the MMU bank and the + * transaction attribute determined by the fetch address, + * regardless of CPU state. This is painful for QEMU + * to handle, because it would mean we need to encode + * into the mmu_idx not just the (user, negpri) information + * for the current security state but also that for the + * other security state, which would balloon the number + * of mmu_idx values needed alarmingly. + * Fortunately we can avoid this because it's not actually + * possible to arbitrarily execute code from memory with + * the wrong security attribute: it will always generate + * an exception of some kind or another, apart from the + * special case of an NS CPU executing an SG instruction + * in S&NSC memory. So we always just fail the translation + * here and sort things out in the exception handler + * (including possibly emulating an SG instruction). + */ + if (sattrs.ns != !secure) { + *fsr = sattrs.nsc ? M_FAKE_FSR_NSC_EXEC : M_FAKE_FSR_SFAULT; + return true; + } + } else { + /* For data accesses we always use the MMU bank indicated + * by the current CPU state, but the security attributes + * might downgrade a secure access to nonsecure. + */ + if (sattrs.ns) { + txattrs->secure = false; + } else if (!secure) { + /* NS access to S memory must fault. + * Architecturally we should first check whether the + * MPU information for this address indicates that we + * are doing an unaligned access to Device memory, which + * should generate a UsageFault instead. QEMU does not + * currently check for that kind of unaligned access though. + * If we added it we would need to do so as a special case + * for M_FAKE_FSR_SFAULT in arm_v7m_cpu_do_interrupt(). + */ + *fsr = M_FAKE_FSR_SFAULT; + return true; + } + } + } + /* Unlike the ARM ARM pseudocode, we don't need to check whether this * was an exception vector read from the vector table (which is always * done using the default system address map), because those accesses @@ -8777,7 +9302,7 @@ static bool get_phys_addr(CPUARMState *env, target_ulong address, if (arm_feature(env, ARM_FEATURE_V8)) { /* PMSAv8 */ ret = get_phys_addr_pmsav8(env, address, access_type, mmu_idx, - phys_ptr, prot, fsr); + phys_ptr, attrs, prot, fsr); } else if (arm_feature(env, ARM_FEATURE_V7)) { /* PMSAv7 */ ret = get_phys_addr_pmsav7(env, address, access_type, mmu_idx, @@ -9100,11 +9625,11 @@ void HELPER(v7m_msr)(CPUARMState *env, uint32_t maskreg, uint32_t val) 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. - * switch_v7m_sp() deals with updating the SPSEL bit in + * write_v7m_control_spsel() deals with updating the SPSEL bit in * env->v7m.control, so we only need update the others. */ if (!arm_v7m_is_handler_mode(env)) { - switch_v7m_sp(env, (val & R_V7M_CONTROL_SPSEL_MASK) != 0); + write_v7m_control_spsel(env, (val & R_V7M_CONTROL_SPSEL_MASK) != 0); } env->v7m.control[env->v7m.secure] &= ~R_V7M_CONTROL_NPRIV_MASK; env->v7m.control[env->v7m.secure] |= val & R_V7M_CONTROL_NPRIV_MASK; diff --git a/target/arm/internals.h b/target/arm/internals.h index 18be3702f2..fd9a7e8181 100644 --- a/target/arm/internals.h +++ b/target/arm/internals.h @@ -71,6 +71,21 @@ FIELD(V7M_EXCRET, DCRS, 5, 1) FIELD(V7M_EXCRET, S, 6, 1) FIELD(V7M_EXCRET, RES1, 7, 25) /* including the must-be-1 prefix */ +/* We use a few fake FSR values for internal purposes in M profile. + * M profile cores don't have A/R format FSRs, but currently our + * get_phys_addr() code assumes A/R profile and reports failures via + * an A/R format FSR value. We then translate that into the proper + * M profile exception and FSR status bit in arm_v7m_cpu_do_interrupt(). + * Mostly the FSR values we use for this are those defined for v7PMSA, + * since we share some of that codepath. A few kinds of fault are + * only for M profile and have no A/R equivalent, though, so we have + * to pick a value from the reserved range (which we never otherwise + * generate) to use for these. + * These values will never be visible to the guest. + */ +#define M_FAKE_FSR_NSC_EXEC 0xf /* NS executing in S&NSC memory */ +#define M_FAKE_FSR_SFAULT 0xe /* SecureFault INVTRAN, INVEP or AUVIOL */ + /* * For AArch64, map a given EL to an index in the banked_spsr array. * Note that this mapping and the AArch32 mapping defined in bank_number() diff --git a/target/arm/machine.c b/target/arm/machine.c index 29df7ac87d..176274629c 100644 --- a/target/arm/machine.c +++ b/target/arm/machine.c @@ -242,6 +242,13 @@ static bool s_rnr_vmstate_validate(void *opaque, int version_id) return cpu->env.pmsav7.rnr[M_REG_S] < cpu->pmsav7_dregion; } +static bool sau_rnr_vmstate_validate(void *opaque, int version_id) +{ + ARMCPU *cpu = opaque; + + return cpu->env.sau.rnr < cpu->sau_sregion; +} + static bool m_security_needed(void *opaque) { ARMCPU *cpu = opaque; @@ -276,6 +283,15 @@ static const VMStateDescription vmstate_m_security = { VMSTATE_UINT32(env.v7m.ccr[M_REG_S], ARMCPU), VMSTATE_UINT32(env.v7m.mmfar[M_REG_S], ARMCPU), VMSTATE_UINT32(env.v7m.cfsr[M_REG_S], ARMCPU), + VMSTATE_UINT32(env.v7m.sfsr, ARMCPU), + VMSTATE_UINT32(env.v7m.sfar, ARMCPU), + VMSTATE_VARRAY_UINT32(env.sau.rbar, ARMCPU, sau_sregion, 0, + vmstate_info_uint32, uint32_t), + VMSTATE_VARRAY_UINT32(env.sau.rlar, ARMCPU, sau_sregion, 0, + vmstate_info_uint32, uint32_t), + VMSTATE_UINT32(env.sau.rnr, ARMCPU), + VMSTATE_VALIDATE("SAU_RNR is valid", sau_rnr_vmstate_validate), + VMSTATE_UINT32(env.sau.ctrl, ARMCPU), VMSTATE_END_OF_LIST() } }; diff --git a/target/arm/op_helper.c b/target/arm/op_helper.c index 6a60464ab9..3914145709 100644 --- a/target/arm/op_helper.c +++ b/target/arm/op_helper.c @@ -953,22 +953,29 @@ void HELPER(pre_smc)(CPUARMState *env, uint32_t syndrome) */ bool undef = arm_feature(env, ARM_FEATURE_AARCH64) ? smd : smd && !secure; - if (arm_is_psci_call(cpu, EXCP_SMC)) { - /* If PSCI is enabled and this looks like a valid PSCI call then - * that overrides the architecturally mandated SMC behaviour. + if (!arm_feature(env, ARM_FEATURE_EL3) && + cpu->psci_conduit != QEMU_PSCI_CONDUIT_SMC) { + /* If we have no EL3 then SMC always UNDEFs and can't be + * trapped to EL2. PSCI-via-SMC is a sort of ersatz EL3 + * firmware within QEMU, and we want an EL2 guest to be able + * to forbid its EL1 from making PSCI calls into QEMU's + * "firmware" via HCR.TSC, so for these purposes treat + * PSCI-via-SMC as implying an EL3. */ - return; - } - - if (!arm_feature(env, ARM_FEATURE_EL3)) { - /* If we have no EL3 then SMC always UNDEFs */ undef = true; } else if (!secure && cur_el == 1 && (env->cp15.hcr_el2 & HCR_TSC)) { - /* In NS EL1, HCR controlled routing to EL2 has priority over SMD. */ + /* In NS EL1, HCR controlled routing to EL2 has priority over SMD. + * We also want an EL2 guest to be able to forbid its EL1 from + * making PSCI calls into QEMU's "firmware" via HCR.TSC. + */ raise_exception(env, EXCP_HYP_TRAP, syndrome, 2); } - if (undef) { + /* If PSCI is enabled and this looks like a valid PSCI call then + * suppress the UNDEF -- we'll catch the SMC exception and + * implement the PSCI call behaviour there. + */ + if (undef && !arm_is_psci_call(cpu, EXCP_SMC)) { raise_exception(env, EXCP_UDEF, syn_uncategorized(), exception_target_el(env)); } |