From 6000531e19964756673a5f4b694a649ef883605a Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Mon, 29 Apr 2019 17:36:01 +0100 Subject: [PATCH] target/arm: Activate M-profile floating point context when FPCCR.ASPEN is set The M-profile FPCCR.ASPEN bit indicates that automatic floating-point context preservation is enabled. Before executing any floating-point instruction, if FPCCR.ASPEN is set and the CONTROL FPCA/SFPA bits indicate that there is no active floating point context then we must create a new context (by initializing FPSCR and setting FPCA/SFPA to indicate that the context is now active). In the pseudocode this is handled by ExecuteFPCheck(). Implement this with a new TB flag which tracks whether we need to create a new FP context. Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson Message-id: 20190416125744.27770-20-peter.maydell@linaro.org --- target/arm/cpu.h | 2 ++ target/arm/helper.c | 13 +++++++++++++ target/arm/translate.c | 29 +++++++++++++++++++++++++++++ target/arm/translate.h | 1 + 4 files changed, 45 insertions(+) diff --git a/target/arm/cpu.h b/target/arm/cpu.h index a2cf9aae3a..d4996a4d20 100644 --- a/target/arm/cpu.h +++ b/target/arm/cpu.h @@ -3153,6 +3153,8 @@ 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 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 */ FIELD(TBFLAG_A32, FPCCR_S_WRONG, 20, 1) /* For M profile only, Handler (ie not Thread) mode */ diff --git a/target/arm/helper.c b/target/arm/helper.c index 8290f56c65..84e3790a9d 100644 --- a/target/arm/helper.c +++ b/target/arm/helper.c @@ -13422,6 +13422,19 @@ void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc, flags = FIELD_DP32(flags, TBFLAG_A32, FPCCR_S_WRONG, 1); } + if (arm_feature(env, ARM_FEATURE_M) && + (env->v7m.fpccr[env->v7m.secure] & R_V7M_FPCCR_ASPEN_MASK) && + (!(env->v7m.control[M_REG_S] & R_V7M_CONTROL_FPCA_MASK) || + (env->v7m.secure && + !(env->v7m.control[M_REG_S] & R_V7M_CONTROL_SFPA_MASK)))) { + /* + * ASPEN is set, but FPCA/SFPA indicate that there is no active + * FP context; we must create a new FP context before executing + * any FP insn. + */ + flags = FIELD_DP32(flags, TBFLAG_A32, NEW_FP_CTXT_NEEDED, 1); + } + *pflags = flags; *cs_base = 0; } diff --git a/target/arm/translate.c b/target/arm/translate.c index f0332ac19e..edb66e7be8 100644 --- a/target/arm/translate.c +++ b/target/arm/translate.c @@ -3438,6 +3438,33 @@ static int disas_vfp_insn(DisasContext *s, uint32_t insn) /* Don't need to do this for any further FP insns in this TB */ s->v8m_fpccr_s_wrong = false; } + + if (s->v7m_new_fp_ctxt_needed) { + /* + * Create new FP context by updating CONTROL.FPCA, CONTROL.SFPA + * and the FPSCR. + */ + TCGv_i32 control, fpscr; + uint32_t bits = R_V7M_CONTROL_FPCA_MASK; + + fpscr = load_cpu_field(v7m.fpdscr[s->v8m_secure]); + gen_helper_vfp_set_fpscr(cpu_env, fpscr); + tcg_temp_free_i32(fpscr); + /* + * We don't need to arrange to end the TB, because the only + * parts of FPSCR which we cache in the TB flags are the VECLEN + * and VECSTRIDE, and those don't exist for M-profile. + */ + + if (s->v8m_secure) { + bits |= R_V7M_CONTROL_SFPA_MASK; + } + control = load_cpu_field(v7m.control[M_REG_S]); + tcg_gen_ori_i32(control, control, bits); + store_cpu_field(control, v7m.control[M_REG_S]); + /* Don't need to do this for any further FP insns in this TB */ + s->v7m_new_fp_ctxt_needed = false; + } } if (extract32(insn, 28, 4) == 0xf) { @@ -13361,6 +13388,8 @@ static void arm_tr_init_disas_context(DisasContextBase *dcbase, CPUState *cs) regime_is_secure(env, dc->mmu_idx); dc->v8m_stackcheck = FIELD_EX32(tb_flags, TBFLAG_A32, STACKCHECK); 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->cp_regs = cpu->cp_regs; dc->features = env->features; diff --git a/target/arm/translate.h b/target/arm/translate.h index 93abff645a..ed8ae2e7e3 100644 --- a/target/arm/translate.h +++ b/target/arm/translate.h @@ -41,6 +41,7 @@ typedef struct DisasContext { bool v8m_secure; /* true if v8M and we're in Secure mode */ 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 */ /* Immediate value in AArch32 SVC insn; must be set if is_jmp == DISAS_SWI * so that top level loop can generate correct syndrome information. */