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qemu/target/arm/m_helper.c
Peter Maydell e534629296 target/arm: Implement M-profile trapping on division by zero 
Unlike A-profile, for M-profile the UDIV and SDIV insns can be
configured to raise an exception on division by zero, using the CCR
DIV_0_TRP bit.

Implement support for setting this bit by making the helper functions
raise the appropriate exception.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210730151636.17254-3-peter.maydell@linaro.org
2021-08-25 10:48:50 +01:00

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/*
* 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 "qemu/units.h"
#include "target/arm/idau.h"
#include "trace.h"
#include "cpu.h"
#include "internals.h"
#include "exec/gdbstub.h"
#include "exec/helper-proto.h"
#include "qemu/host-utils.h"
#include "qemu/main-loop.h"
#include "qemu/bitops.h"
#include "qemu/crc32c.h"
#include "qemu/qemu-print.h"
#include "exec/exec-all.h"
#include <zlib.h> /* For crc32 */
#include "semihosting/semihost.h"
#include "sysemu/cpus.h"
#include "sysemu/kvm.h"
#include "qemu/range.h"
#include "qapi/qapi-commands-machine-target.h"
#include "qapi/error.h"
#include "qemu/guest-random.h"
#ifdef CONFIG_TCG
#include "arm_ldst.h"
#include "exec/cpu_ldst.h"
#include "semihosting/common-semi.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;
}
#else
/*
* 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;
MemTxAttrs attrs = {};
MemTxResult txres;
target_ulong page_size;
hwaddr physaddr;
int prot;
ARMMMUFaultInfo fi = {};
ARMCacheAttrs cacheattrs = {};
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, &physaddr,
&attrs, &prot, &page_size, &fi, &cacheattrs)) {
/* 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, attrs), physaddr, value,
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;
MemTxAttrs attrs = {};
MemTxResult txres;
target_ulong page_size;
hwaddr physaddr;
int prot;
ARMMMUFaultInfo fi = {};
ARMCacheAttrs cacheattrs = {};
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, &physaddr,
&attrs, &prot, &page_size, &fi, &cacheattrs)) {
/* 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, attrs), physaddr,
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 = 1;
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 = 1;
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 = 1;
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;
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, &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;
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 || !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. 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;
void *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;
TCGMemOpIdx 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_LE, arm_to_core_mmu_idx(mmu_idx));
newpc = helper_le_ldul_mmu(env, frameptr, oi, 0);
newpsr = helper_le_ldul_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,
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 = {};
MemTxAttrs attrs = {};
ARMMMUFaultInfo fi = {};
ARMCacheAttrs cacheattrs = {};
MemTxResult txres;
target_ulong page_size;
hwaddr physaddr;
int prot;
v8m_security_lookup(env, addr, MMU_INST_FETCH, mmu_idx, &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, &physaddr,
&attrs, &prot, &page_size, &fi, &cacheattrs)) {
/* 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, attrs), physaddr,
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;
MemTxAttrs attrs = {};
MemTxResult txres;
target_ulong page_size;
hwaddr physaddr;
int prot;
ARMMMUFaultInfo fi = {};
ARMCacheAttrs cacheattrs = {};
uint32_t value;
if (get_phys_addr(env, addr, MMU_DATA_LOAD, mmu_idx, &physaddr,
&attrs, &prot, &page_size, &fi, &cacheattrs)) {
/* 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, attrs), physaddr,
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, 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, 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->exception_index);
/*
* 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.
*/
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
env->regs[0] = 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 (!env->v7m.secure) {
return 0;
}
return env->v7m.basepri[M_REG_NS];
case 0x93: /* FAULTMASK_NS */
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 */
return env->v7m.basepri[env->v7m.secure];
case 19: /* FAULTMASK */
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 (!env->v7m.secure || !arm_feature(env, ARM_FEATURE_M_MAIN)) {
return;
}
env->v7m.basepri[M_REG_NS] = val & 0xff;
return;
case 0x93: /* FAULTMASK_NS */
if (!env->v7m.secure || !arm_feature(env, ARM_FEATURE_M_MAIN)) {
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;
int prot;
ARMMMUFaultInfo fi = {};
MemTxAttrs attrs = {};
hwaddr phys_addr;
ARMMMUIdx mmu_idx;
uint32_t mregion;
bool targetpriv;
bool targetsec = env->v7m.secure;
bool is_subpage;
/*
* 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) {
/* We can ignore the return value as prot is always set */
pmsav8_mpu_lookup(env, addr, MMU_DATA_LOAD, mmu_idx,
&phys_addr, &attrs, &prot, &is_subpage,
&fi, &mregion);
if (mregion == -1) {
mrvalid = false;
mregion = 0;
} else {
mrvalid = true;
}
r = prot & PAGE_READ;
rw = 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, &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 */
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;
}
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);
}
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