diff options
| -rw-r--r-- | target/arm/internals.h | 6 | ||||
| -rw-r--r-- | target/arm/translate-a64.c | 139 | ||||
| -rw-r--r-- | target/arm/translate.h | 9 |
3 files changed, 152 insertions, 2 deletions
diff --git a/target/arm/internals.h b/target/arm/internals.h index a6fd4582b2..d01a3f9f44 100644 --- a/target/arm/internals.h +++ b/target/arm/internals.h @@ -268,6 +268,7 @@ enum arm_exception_class { EC_FPIDTRAP = 0x08, EC_PACTRAP = 0x09, EC_CP14RRTTRAP = 0x0c, + EC_BTITRAP = 0x0d, EC_ILLEGALSTATE = 0x0e, EC_AA32_SVC = 0x11, EC_AA32_HVC = 0x12, @@ -439,6 +440,11 @@ static inline uint32_t syn_pactrap(void) return EC_PACTRAP << ARM_EL_EC_SHIFT; } +static inline uint32_t syn_btitrap(int btype) +{ + return (EC_BTITRAP << ARM_EL_EC_SHIFT) | btype; +} + static inline uint32_t syn_insn_abort(int same_el, int ea, int s1ptw, int fsc) { return (EC_INSNABORT << ARM_EL_EC_SHIFT) | (same_el << ARM_EL_EC_SHIFT) diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c index a92fd43378..7034fb3d12 100644 --- a/target/arm/translate-a64.c +++ b/target/arm/translate-a64.c @@ -128,6 +128,16 @@ static inline int get_a64_user_mem_index(DisasContext *s) return arm_to_core_mmu_idx(useridx); } +static void reset_btype(DisasContext *s) +{ + if (s->btype != 0) { + TCGv_i32 zero = tcg_const_i32(0); + tcg_gen_st_i32(zero, cpu_env, offsetof(CPUARMState, btype)); + tcg_temp_free_i32(zero); + s->btype = 0; + } +} + void aarch64_cpu_dump_state(CPUState *cs, FILE *f, fprintf_function cpu_fprintf, int flags) { @@ -13756,6 +13766,90 @@ static void disas_data_proc_simd_fp(DisasContext *s, uint32_t insn) } } +/** + * is_guarded_page: + * @env: The cpu environment + * @s: The DisasContext + * + * Return true if the page is guarded. + */ +static bool is_guarded_page(CPUARMState *env, DisasContext *s) +{ +#ifdef CONFIG_USER_ONLY + return false; /* FIXME */ +#else + uint64_t addr = s->base.pc_first; + int mmu_idx = arm_to_core_mmu_idx(s->mmu_idx); + unsigned int index = tlb_index(env, mmu_idx, addr); + CPUTLBEntry *entry = tlb_entry(env, mmu_idx, addr); + + /* + * We test this immediately after reading an insn, which means + * that any normal page must be in the TLB. The only exception + * would be for executing from flash or device memory, which + * does not retain the TLB entry. + * + * FIXME: Assume false for those, for now. We could use + * arm_cpu_get_phys_page_attrs_debug to re-read the page + * table entry even for that case. + */ + return (tlb_hit(entry->addr_code, addr) && + env->iotlb[mmu_idx][index].attrs.target_tlb_bit0); +#endif +} + +/** + * btype_destination_ok: + * @insn: The instruction at the branch destination + * @bt: SCTLR_ELx.BT + * @btype: PSTATE.BTYPE, and is non-zero + * + * On a guarded page, there are a limited number of insns + * that may be present at the branch target: + * - branch target identifiers, + * - paciasp, pacibsp, + * - BRK insn + * - HLT insn + * Anything else causes a Branch Target Exception. + * + * Return true if the branch is compatible, false to raise BTITRAP. + */ +static bool btype_destination_ok(uint32_t insn, bool bt, int btype) +{ + if ((insn & 0xfffff01fu) == 0xd503201fu) { + /* HINT space */ + switch (extract32(insn, 5, 7)) { + case 0b011001: /* PACIASP */ + case 0b011011: /* PACIBSP */ + /* + * If SCTLR_ELx.BT, then PACI*SP are not compatible + * with btype == 3. Otherwise all btype are ok. + */ + return !bt || btype != 3; + case 0b100000: /* BTI */ + /* Not compatible with any btype. */ + return false; + case 0b100010: /* BTI c */ + /* Not compatible with btype == 3 */ + return btype != 3; + case 0b100100: /* BTI j */ + /* Not compatible with btype == 2 */ + return btype != 2; + case 0b100110: /* BTI jc */ + /* Compatible with any btype. */ + return true; + } + } else { + switch (insn & 0xffe0001fu) { + case 0xd4200000u: /* BRK */ + case 0xd4400000u: /* HLT */ + /* Give priority to the breakpoint exception. */ + return true; + } + } + return false; +} + /* C3.1 A64 instruction index by encoding */ static void disas_a64_insn(CPUARMState *env, DisasContext *s) { @@ -13767,6 +13861,43 @@ static void disas_a64_insn(CPUARMState *env, DisasContext *s) s->fp_access_checked = false; + if (dc_isar_feature(aa64_bti, s)) { + if (s->base.num_insns == 1) { + /* + * At the first insn of the TB, compute s->guarded_page. + * We delayed computing this until successfully reading + * the first insn of the TB, above. This (mostly) ensures + * that the softmmu tlb entry has been populated, and the + * page table GP bit is available. + * + * Note that we need to compute this even if btype == 0, + * because this value is used for BR instructions later + * where ENV is not available. + */ + s->guarded_page = is_guarded_page(env, s); + + /* First insn can have btype set to non-zero. */ + tcg_debug_assert(s->btype >= 0); + + /* + * Note that the Branch Target Exception has fairly high + * priority -- below debugging exceptions but above most + * everything else. This allows us to handle this now + * instead of waiting until the insn is otherwise decoded. + */ + if (s->btype != 0 + && s->guarded_page + && !btype_destination_ok(insn, s->bt, s->btype)) { + gen_exception_insn(s, 4, EXCP_UDEF, syn_btitrap(s->btype), + default_exception_el(s)); + return; + } + } else { + /* Not the first insn: btype must be 0. */ + tcg_debug_assert(s->btype == 0); + } + } + switch (extract32(insn, 25, 4)) { case 0x0: case 0x1: case 0x3: /* UNALLOCATED */ unallocated_encoding(s); @@ -13803,6 +13934,14 @@ static void disas_a64_insn(CPUARMState *env, DisasContext *s) /* if we allocated any temporaries, free them here */ free_tmp_a64(s); + + /* + * After execution of most insns, btype is reset to 0. + * Note that we set btype == -1 when the insn sets btype. + */ + if (s->btype > 0 && s->base.is_jmp != DISAS_NORETURN) { + reset_btype(s); + } } static void aarch64_tr_init_disas_context(DisasContextBase *dcbase, diff --git a/target/arm/translate.h b/target/arm/translate.h index 3d5e8bacac..f73939d7b4 100644 --- a/target/arm/translate.h +++ b/target/arm/translate.h @@ -71,8 +71,13 @@ typedef struct DisasContext { bool pauth_active; /* True with v8.5-BTI and SCTLR_ELx.BT* set. */ bool bt; - /* A copy of PSTATE.BTYPE, which will be 0 without v8.5-BTI. */ - uint8_t btype; + /* + * >= 0, a copy of PSTATE.BTYPE, which will be 0 without v8.5-BTI. + * < 0, set by the current instruction. + */ + int8_t btype; + /* True if this page is guarded. */ + bool guarded_page; /* Bottom two bits of XScale c15_cpar coprocessor access control reg */ int c15_cpar; /* TCG op of the current insn_start. */ |