From 34b97400818d4cd551677428d50d8e68bf9f8ccc Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Sun, 4 Mar 2018 01:14:20 -0500 Subject: [PATCH] target/arm: Don't do MPU lookups for addresses in M profile PPB region The M profile PMSAv7 specification says that if the address being looked up is in the PPB region (0xe0000000 - 0xe00fffff) then we do not use the MPU regions but always use the default memory map. Implement this (we were previously behaving like an R profile PMSAv7, which does not special case this). Backports commit 38aaa60ca464b48e6feef346709e97335d01b289 from qemu --- qemu/target/arm/helper.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/qemu/target/arm/helper.c b/qemu/target/arm/helper.c index 834067d4..5d4d1212 100644 --- a/qemu/target/arm/helper.c +++ b/qemu/target/arm/helper.c @@ -7512,6 +7512,13 @@ static bool pmsav7_use_background_region(ARMCPU *cpu, } } +static inline bool m_is_ppb_region(CPUARMState *env, uint32_t address) +{ + /* True if address is in the M profile PPB region 0xe0000000 - 0xe00fffff */ + return arm_feature(env, ARM_FEATURE_M) && + extract32(address, 20, 12) == 0xe00; +} + 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) @@ -7523,7 +7530,15 @@ static bool get_phys_addr_pmsav7(CPUARMState *env, uint32_t address, *phys_ptr = address; *prot = 0; - if (regime_translation_disabled(env, mmu_idx)) { /* MPU disabled */ + if (regime_translation_disabled(env, mmu_idx) || + m_is_ppb_region(env, address)) { + /* MPU disabled or M profile PPB access: use default memory map. + * The other case which uses the default memory map in the + * v7M ARM ARM pseudocode is exception vector reads from the vector + * table. In QEMU those accesses are done in arm_v7m_load_vector(), + * which always does a direct read using address_space_ldl(), rather + * than going via this function, so we don't need to check that here. + */ get_phys_addr_pmsav7_default(env, mmu_idx, address, prot); } else { /* MPU enabled */ for (n = (int)cpu->pmsav7_dregion - 1; n >= 0; n--) {