diff options
Diffstat (limited to 'target')
| -rw-r--r-- | target/arm/cpu.h | 8 | ||||
| -rw-r--r-- | target/arm/helper.c | 65 |
2 files changed, 50 insertions, 23 deletions
diff --git a/target/arm/cpu.h b/target/arm/cpu.h index 8afceca873..ad6eff498b 100644 --- a/target/arm/cpu.h +++ b/target/arm/cpu.h @@ -991,6 +991,11 @@ 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 +1076,8 @@ 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); } } diff --git a/target/arm/helper.c b/target/arm/helper.c index 7548d4c6ec..36173e21a7 100644 --- a/target/arm/helper.c +++ b/target/arm/helper.c @@ -6059,21 +6059,44 @@ 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. This may change the current + * stack pointer between Main and Process stack pointers. + */ +static void write_v7m_control_spsel(CPUARMState *env, bool new_spsel) { uint32_t tmp; - uint32_t old_control = env->v7m.control[env->v7m.secure]; - bool old_spsel = old_control & R_V7M_CONTROL_SPSEL_MASK; + bool new_is_psp, old_is_psp = v7m_using_psp(env); + + env->v7m.control[env->v7m.secure] = + deposit32(env->v7m.control[env->v7m.secure], + R_V7M_CONTROL_SPSEL_SHIFT, + R_V7M_CONTROL_SPSEL_LENGTH, new_spsel); + + new_is_psp = v7m_using_psp(env); - if (old_spsel != new_spsel) { + if (old_is_psp != new_is_psp) { tmp = env->v7m.other_sp; env->v7m.other_sp = env->regs[13]; env->regs[13] = tmp; + } +} + +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.control[env->v7m.secure] = deposit32(old_control, - R_V7M_CONTROL_SPSEL_SHIFT, - R_V7M_CONTROL_SPSEL_LENGTH, 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; } } @@ -6159,13 +6182,11 @@ static uint32_t *get_v7m_sp_ptr(CPUARMState *env, bool secure, bool threadmode, bool want_psp = threadmode && spsel; if (secure == env->v7m.secure) { - /* Currently switch_v7m_sp switches SP as it updates SPSEL, - * so the SP we want is always in regs[13]. - * When we decouple SPSEL from the actually selected SP - * we need to check want_psp against v7m_using_psp() - * to see whether we need regs[13] or v7m.other_sp. - */ - return &env->regs[13]; + 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; @@ -6208,7 +6229,7 @@ static void v7m_exception_taken(ARMCPU *cpu, uint32_t lr) uint32_t addr; armv7m_nvic_acknowledge_irq(env->nvic); - switch_v7m_sp(env, 0); + write_v7m_control_spsel(env, 0); arm_clear_exclusive(env); /* Clear IT bits */ env->condexec_bits = 0; @@ -6354,11 +6375,11 @@ static void do_v7m_exception_exit(ARMCPU *cpu) return; } - /* Set CONTROL.SPSEL from excret.SPSEL. For QEMU this currently - * causes us to switch the active SP, but we will change this - * later to not do that so we can support v8M. + /* 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. */ - switch_v7m_sp(env, return_to_sp_process); + write_v7m_control_spsel(env, return_to_sp_process); { /* The stack pointer we should be reading the exception frame from @@ -9173,11 +9194,11 @@ 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; |