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target/arm: Don't allow guest to make System space executable for M profile

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For an M profile v7PMSA, the system space (0xe0000000 - 0xffffffff) can
never be executable, even if the guest tries to set the MPU registers
up that way. Enforce this restriction.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 1501153150-19984-3-git-send-email-peter.maydell@linaro.org
This commit is contained in:
Peter Maydell 2017-07-27 11:59:07 +01:00
parent 38aaa60ca4
commit bf446a11df
1 changed files with 15 additions and 1 deletions
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16
target/arm/helper.c
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@ -8251,6 +8251,14 @@ static inline bool m_is_ppb_region(CPUARMState *env, uint32_t address)
extract32(address, 20, 12) == 0xe00;
}
static inline bool m_is_system_region(CPUARMState *env, uint32_t address)
{
/* True if address is in the M profile system region
* 0xe0000000 - 0xffffffff
*/
return arm_feature(env, ARM_FEATURE_M) && extract32(address, 29, 3) == 0x7;
}
static bool get_phys_addr_pmsav7(CPUARMState *env, uint32_t address,
int access_type, ARMMMUIdx mmu_idx,
hwaddr *phys_ptr, int *prot, uint32_t *fsr)
@ -8354,6 +8362,12 @@ static bool get_phys_addr_pmsav7(CPUARMState *env, uint32_t address,
get_phys_addr_pmsav7_default(env, mmu_idx, address, prot);
} else { /* a MPU hit! */
uint32_t ap = extract32(env->pmsav7.dracr[n], 8, 3);
uint32_t xn = extract32(env->pmsav7.dracr[n], 12, 1);
if (m_is_system_region(env, address)) {
/* System space is always execute never */
xn = 1;
}
if (is_user) { /* User mode AP bit decoding */
switch (ap) {
@ -8394,7 +8408,7 @@ static bool get_phys_addr_pmsav7(CPUARMState *env, uint32_t address,
}
/* execute never */
if (env->pmsav7.dracr[n] & (1 << 12)) {
if (xn) {
*prot &= ~PAGE_EXEC;
}
}