target/arm: Move helper_exception_return to helper-a64.c

This function is only used by AArch64.  Code movement only.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20190108223129.5570-11-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 0 insertions, 155 deletions

diff --git a/target/arm/op_helper.c b/target/arm/op_helper.c
index 8b31c6a13b..c998eadfaa 100644
--- a/target/arm/op_helper.c
+++ b/target/arm/op_helper.c
@@ -1029,161 +1029,6 @@ void HELPER(pre_smc)(CPUARMState *env, uint32_t syndrome)
     }
 }
 
-static int el_from_spsr(uint32_t spsr)
-{
-    /* Return the exception level that this SPSR is requesting a return to,
-     * or -1 if it is invalid (an illegal return)
-     */
-    if (spsr & PSTATE_nRW) {
-        switch (spsr & CPSR_M) {
-        case ARM_CPU_MODE_USR:
-            return 0;
-        case ARM_CPU_MODE_HYP:
-            return 2;
-        case ARM_CPU_MODE_FIQ:
-        case ARM_CPU_MODE_IRQ:
-        case ARM_CPU_MODE_SVC:
-        case ARM_CPU_MODE_ABT:
-        case ARM_CPU_MODE_UND:
-        case ARM_CPU_MODE_SYS:
-            return 1;
-        case ARM_CPU_MODE_MON:
-            /* Returning to Mon from AArch64 is never possible,
-             * so this is an illegal return.
-             */
-        default:
-            return -1;
-        }
-    } else {
-        if (extract32(spsr, 1, 1)) {
-            /* Return with reserved M[1] bit set */
-            return -1;
-        }
-        if (extract32(spsr, 0, 4) == 1) {
-            /* return to EL0 with M[0] bit set */
-            return -1;
-        }
-        return extract32(spsr, 2, 2);
-    }
-}
-
-void HELPER(exception_return)(CPUARMState *env)
-{
-    int cur_el = arm_current_el(env);
-    unsigned int spsr_idx = aarch64_banked_spsr_index(cur_el);
-    uint32_t spsr = env->banked_spsr[spsr_idx];
-    int new_el;
-    bool return_to_aa64 = (spsr & PSTATE_nRW) == 0;
-
-    aarch64_save_sp(env, cur_el);
-
-    arm_clear_exclusive(env);
-
-    /* We must squash the PSTATE.SS bit to zero unless both of the
-     * following hold:
-     *  1. debug exceptions are currently disabled
-     *  2. singlestep will be active in the EL we return to
-     * We check 1 here and 2 after we've done the pstate/cpsr write() to
-     * transition to the EL we're going to.
-     */
-    if (arm_generate_debug_exceptions(env)) {
-        spsr &= ~PSTATE_SS;
-    }
-
-    new_el = el_from_spsr(spsr);
-    if (new_el == -1) {
-        goto illegal_return;
-    }
-    if (new_el > cur_el
-        || (new_el == 2 && !arm_feature(env, ARM_FEATURE_EL2))) {
-        /* Disallow return to an EL which is unimplemented or higher
-         * than the current one.
-         */
-        goto illegal_return;
-    }
-
-    if (new_el != 0 && arm_el_is_aa64(env, new_el) != return_to_aa64) {
-        /* Return to an EL which is configured for a different register width */
-        goto illegal_return;
-    }
-
-    if (new_el == 2 && arm_is_secure_below_el3(env)) {
-        /* Return to the non-existent secure-EL2 */
-        goto illegal_return;
-    }
-
-    if (new_el == 1 && (arm_hcr_el2_eff(env) & HCR_TGE)) {
-        goto illegal_return;
-    }
-
-    qemu_mutex_lock_iothread();
-    arm_call_pre_el_change_hook(arm_env_get_cpu(env));
-    qemu_mutex_unlock_iothread();
-
-    if (!return_to_aa64) {
-        env->aarch64 = 0;
-        /* We do a raw CPSR write because aarch64_sync_64_to_32()
-         * will sort the register banks out for us, and we've already
-         * caught all the bad-mode cases in el_from_spsr().
-         */
-        cpsr_write(env, spsr, ~0, CPSRWriteRaw);
-        if (!arm_singlestep_active(env)) {
-            env->uncached_cpsr &= ~PSTATE_SS;
-        }
-        aarch64_sync_64_to_32(env);
-
-        if (spsr & CPSR_T) {
-            env->regs[15] = env->elr_el[cur_el] & ~0x1;
-        } else {
-            env->regs[15] = env->elr_el[cur_el] & ~0x3;
-        }
-        qemu_log_mask(CPU_LOG_INT, "Exception return from AArch64 EL%d to "
-                      "AArch32 EL%d PC 0x%" PRIx32 "\n",
-                      cur_el, new_el, env->regs[15]);
-    } else {
-        env->aarch64 = 1;
-        pstate_write(env, spsr);
-        if (!arm_singlestep_active(env)) {
-            env->pstate &= ~PSTATE_SS;
-        }
-        aarch64_restore_sp(env, new_el);
-        env->pc = env->elr_el[cur_el];
-        qemu_log_mask(CPU_LOG_INT, "Exception return from AArch64 EL%d to "
-                      "AArch64 EL%d PC 0x%" PRIx64 "\n",
-                      cur_el, new_el, env->pc);
-    }
-    /*
-     * Note that cur_el can never be 0.  If new_el is 0, then
-     * el0_a64 is return_to_aa64, else el0_a64 is ignored.
-     */
-    aarch64_sve_change_el(env, cur_el, new_el, return_to_aa64);
-
-    qemu_mutex_lock_iothread();
-    arm_call_el_change_hook(arm_env_get_cpu(env));
-    qemu_mutex_unlock_iothread();
-
-    return;
-
-illegal_return:
-    /* Illegal return events of various kinds have architecturally
-     * mandated behaviour:
-     * restore NZCV and DAIF from SPSR_ELx
-     * set PSTATE.IL
-     * restore PC from ELR_ELx
-     * no change to exception level, execution state or stack pointer
-     */
-    env->pstate |= PSTATE_IL;
-    env->pc = env->elr_el[cur_el];
-    spsr &= PSTATE_NZCV | PSTATE_DAIF;
-    spsr |= pstate_read(env) & ~(PSTATE_NZCV | PSTATE_DAIF);
-    pstate_write(env, spsr);
-    if (!arm_singlestep_active(env)) {
-        env->pstate &= ~PSTATE_SS;
-    }
-    qemu_log_mask(LOG_GUEST_ERROR, "Illegal exception return at EL%d: "
-                  "resuming execution at 0x%" PRIx64 "\n", cur_el, env->pc);
-}
-
 /* Return true if the linked breakpoint entry lbn passes its checks */
 static bool linked_bp_matches(ARMCPU *cpu, int lbn)
 {