diff options
| -rw-r--r-- | target/arm/cpu.h | 3 | ||||
| -rw-r--r-- | target/arm/helper.c | 112 | ||||
| -rw-r--r-- | target/arm/helper.h | 2 | ||||
| -rw-r--r-- | target/arm/translate.c | 22 | ||||
| -rw-r--r-- | target/arm/translate.h | 1 |
5 files changed, 140 insertions, 0 deletions
diff --git a/target/arm/cpu.h b/target/arm/cpu.h index ed3069341d..0b10aefb93 100644 --- a/target/arm/cpu.h +++ b/target/arm/cpu.h @@ -57,6 +57,7 @@ #define EXCP_NOCP 17 /* v7M NOCP UsageFault */ #define EXCP_INVSTATE 18 /* v7M INVSTATE UsageFault */ #define EXCP_STKOF 19 /* v8M STKOF UsageFault */ +#define EXCP_LAZYFP 20 /* v7M fault during lazy FP stacking */ /* NB: add new EXCP_ defines to the array in arm_log_exception() too */ #define ARMV7M_EXCP_RESET 1 @@ -3172,6 +3173,8 @@ FIELD(TBFLAG_A32, NS, 6, 1) FIELD(TBFLAG_A32, VFPEN, 7, 1) FIELD(TBFLAG_A32, CONDEXEC, 8, 8) FIELD(TBFLAG_A32, SCTLR_B, 16, 1) +/* For M profile only, set if FPCCR.LSPACT is set */ +FIELD(TBFLAG_A32, LSPACT, 18, 1) /* For M profile only, set if we must create a new FP context */ FIELD(TBFLAG_A32, NEW_FP_CTXT_NEEDED, 19, 1) /* For M profile only, set if FPCCR.S does not match current security state */ diff --git a/target/arm/helper.c b/target/arm/helper.c index 4153139085..b11f8aa14d 100644 --- a/target/arm/helper.c +++ b/target/arm/helper.c @@ -7378,6 +7378,12 @@ void HELPER(v7m_blxns)(CPUARMState *env, uint32_t dest) 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(); +} + uint32_t HELPER(v7m_tt)(CPUARMState *env, uint32_t addr, uint32_t op) { /* The TT instructions can be used by unprivileged code, but in @@ -7737,6 +7743,97 @@ pend_fault: 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 = arm_env_get_cpu(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 */ + } + 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); + } + + /* + * 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 */ + int i; + + for (i = 0; i < 32; i += 2) { + *aa32_vfp_dreg(env, i / 2) = 0; + } + vfp_set_fpscr(env, 0); + } + /* + * Otherwise s0 to s15 and FPSCR 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 @@ -9062,6 +9159,7 @@ static void arm_log_exception(int idx) [EXCP_NOCP] = "v7M NOCP UsageFault", [EXCP_INVSTATE] = "v7M INVSTATE UsageFault", [EXCP_STKOF] = "v8M STKOF UsageFault", + [EXCP_LAZYFP] = "v7M exception during lazy FP stacking", }; if (idx >= 0 && idx < ARRAY_SIZE(excnames)) { @@ -9355,6 +9453,12 @@ void arm_v7m_cpu_do_interrupt(CPUState *cs) 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. */ @@ -13483,6 +13587,14 @@ void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc, flags = FIELD_DP32(flags, TBFLAG_A32, NEW_FP_CTXT_NEEDED, 1); } + if (arm_feature(env, ARM_FEATURE_M)) { + bool is_secure = env->v7m.fpccr[M_REG_S] & R_V7M_FPCCR_S_MASK; + + if (env->v7m.fpccr[is_secure] & R_V7M_FPCCR_LSPACT_MASK) { + flags = FIELD_DP32(flags, TBFLAG_A32, LSPACT, 1); + } + } + *pflags = flags; *cs_base = 0; } diff --git a/target/arm/helper.h b/target/arm/helper.h index a09566f795..0a3a80528c 100644 --- a/target/arm/helper.h +++ b/target/arm/helper.h @@ -69,6 +69,8 @@ DEF_HELPER_2(v7m_blxns, void, env, i32) DEF_HELPER_3(v7m_tt, i32, env, i32, i32) +DEF_HELPER_1(v7m_preserve_fp_state, void, env) + DEF_HELPER_2(v8m_stackcheck, void, env, i32) DEF_HELPER_4(access_check_cp_reg, void, env, ptr, i32, i32) diff --git a/target/arm/translate.c b/target/arm/translate.c index edb66e7be8..4f29d09a28 100644 --- a/target/arm/translate.c +++ b/target/arm/translate.c @@ -3424,6 +3424,27 @@ static int disas_vfp_insn(DisasContext *s, uint32_t insn) if (arm_dc_feature(s, ARM_FEATURE_M)) { /* Handle M-profile lazy FP state mechanics */ + /* Trigger lazy-state preservation if necessary */ + if (s->v7m_lspact) { + /* + * Lazy state saving affects external memory and also the NVIC, + * so we must mark it as an IO operation for icount. + */ + if (tb_cflags(s->base.tb) & CF_USE_ICOUNT) { + gen_io_start(); + } + gen_helper_v7m_preserve_fp_state(cpu_env); + if (tb_cflags(s->base.tb) & CF_USE_ICOUNT) { + gen_io_end(); + } + /* + * If the preserve_fp_state helper doesn't throw an exception + * then it will clear LSPACT; we don't need to repeat this for + * any further FP insns in this TB. + */ + s->v7m_lspact = false; + } + /* Update ownership of FP context: set FPCCR.S to match current state */ if (s->v8m_fpccr_s_wrong) { TCGv_i32 tmp; @@ -13390,6 +13411,7 @@ static void arm_tr_init_disas_context(DisasContextBase *dcbase, CPUState *cs) dc->v8m_fpccr_s_wrong = FIELD_EX32(tb_flags, TBFLAG_A32, FPCCR_S_WRONG); dc->v7m_new_fp_ctxt_needed = FIELD_EX32(tb_flags, TBFLAG_A32, NEW_FP_CTXT_NEEDED); + dc->v7m_lspact = FIELD_EX32(tb_flags, TBFLAG_A32, LSPACT); dc->cp_regs = cpu->cp_regs; dc->features = env->features; diff --git a/target/arm/translate.h b/target/arm/translate.h index ed8ae2e7e3..c2348def0d 100644 --- a/target/arm/translate.h +++ b/target/arm/translate.h @@ -42,6 +42,7 @@ typedef struct DisasContext { bool v8m_stackcheck; /* true if we need to perform v8M stack limit checks */ bool v8m_fpccr_s_wrong; /* true if v8M FPCCR.S != v8m_secure */ bool v7m_new_fp_ctxt_needed; /* ASPEN set but no active FP context */ + bool v7m_lspact; /* FPCCR.LSPACT set */ /* Immediate value in AArch32 SVC insn; must be set if is_jmp == DISAS_SWI * so that top level loop can generate correct syndrome information. */ |