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qemu/target/arm/m_helper.c
Peter Maydell 375256a846 target/arm: Handle VPR semantics in existing code 
When MVE is supported, the VPR register has a place on the exception
stack frame in a previously reserved slot just above the FPSCR.
It must also be zeroed in various situations when we invalidate
FPU context.

Update the code which handles the stack frames (exception entry and
exit code, VLLDM, and VLSTM) to save/restore VPR.

Update code which invalidates FP registers (mostly also exception
entry and exit code, but also VSCCLRM and the code in
full_vfp_access_check() that corresponds to the ExecuteFPCheck()
pseudocode) to zero VPR.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210614151007.4545-4-peter.maydell@linaro.org
2021-06-16 14:33:52 +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);
} 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);
}
}
/* 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:
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_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;
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;
return;
case 0x89: /* PSP_NS */
if (!env->v7m.secure) {
return;
}
env->v7m.other_ss_psp = val;
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];
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;
} else {
env->regs[13] = val;
}
break;
case 9: /* PSP */
if (v7m_using_psp(env)) {
env->regs[13] = val;
} else {
env->v7m.other_sp = val;
}
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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