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target/arm: Use MVFR1 feature bits to gate A32/T32 FP16 instructions

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Instead of gating the A32/T32 FP16 conversion instructions on
the ARM_FEATURE_VFP_FP16 flag, switch to our new approach of
looking at ID register bits. In this case MVFR1 fields FPHP
and SIMDHP indicate the presence of these insns.

This change doesn't alter behaviour for any of our CPUs.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20190222170936.13268-2-peter.maydell@linaro.org
This commit is contained in:
Peter Maydell 2019-02-28 10:55:16 +00:00
parent aab7a3786f
commit 602f6e42cf
4 changed files with 54 additions and 14 deletions
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2
target/arm/cpu.c
View File

@ -1014,7 +1014,6 @@ static void arm_cpu_realizefn(DeviceState *dev, Error **errp)
}
if (arm_feature(env, ARM_FEATURE_VFP4)) {
set_feature(env, ARM_FEATURE_VFP3);
set_feature(env, ARM_FEATURE_VFP_FP16);
}
if (arm_feature(env, ARM_FEATURE_VFP3)) {
set_feature(env, ARM_FEATURE_VFP);
@ -1675,7 +1674,6 @@ static void cortex_a9_initfn(Object *obj)
cpu->dtb_compatible = "arm,cortex-a9";
set_feature(&cpu->env, ARM_FEATURE_V7);
set_feature(&cpu->env, ARM_FEATURE_VFP3);
set_feature(&cpu->env, ARM_FEATURE_VFP_FP16);
set_feature(&cpu->env, ARM_FEATURE_NEON);
set_feature(&cpu->env, ARM_FEATURE_THUMB2EE);
set_feature(&cpu->env, ARM_FEATURE_EL3);

37
target/arm/cpu.h
View File

@ -1730,6 +1730,27 @@ FIELD(ID_DFR0, MPROFDBG, 20, 4)
FIELD(ID_DFR0, PERFMON, 24, 4)
FIELD(ID_DFR0, TRACEFILT, 28, 4)
FIELD(MVFR0, SIMDREG, 0, 4)
FIELD(MVFR0, FPSP, 4, 4)
FIELD(MVFR0, FPDP, 8, 4)
FIELD(MVFR0, FPTRAP, 12, 4)
FIELD(MVFR0, FPDIVIDE, 16, 4)
FIELD(MVFR0, FPSQRT, 20, 4)
FIELD(MVFR0, FPSHVEC, 24, 4)
FIELD(MVFR0, FPROUND, 28, 4)
FIELD(MVFR1, FPFTZ, 0, 4)
FIELD(MVFR1, FPDNAN, 4, 4)
FIELD(MVFR1, SIMDLS, 8, 4)
FIELD(MVFR1, SIMDINT, 12, 4)
FIELD(MVFR1, SIMDSP, 16, 4)
FIELD(MVFR1, SIMDHP, 20, 4)
FIELD(MVFR1, FPHP, 24, 4)
FIELD(MVFR1, SIMDFMAC, 28, 4)
FIELD(MVFR2, SIMDMISC, 0, 4)
FIELD(MVFR2, FPMISC, 4, 4)
QEMU_BUILD_BUG_ON(ARRAY_SIZE(((ARMCPU *)0)->ccsidr) <= R_V7M_CSSELR_INDEX_MASK);
/* If adding a feature bit which corresponds to a Linux ELF
@ -1747,7 +1768,6 @@ enum arm_features {
ARM_FEATURE_THUMB2,
ARM_FEATURE_PMSA, /* no MMU; may have Memory Protection Unit */
ARM_FEATURE_VFP3,
ARM_FEATURE_VFP_FP16,
ARM_FEATURE_NEON,
ARM_FEATURE_M, /* Microcontroller profile. */
ARM_FEATURE_OMAPCP, /* OMAP specific CP15 ops handling. */
@ -3293,6 +3313,21 @@ static inline bool isar_feature_aa32_fp16_arith(const ARMISARegisters *id)
return FIELD_EX64(id->id_aa64pfr0, ID_AA64PFR0, FP) == 1;
}
/*
* We always set the FP and SIMD FP16 fields to indicate identical
* levels of support (assuming SIMD is implemented at all), so
* we only need one set of accessors.
*/
static inline bool isar_feature_aa32_fp16_spconv(const ARMISARegisters *id)
{
return FIELD_EX64(id->mvfr1, MVFR1, FPHP) > 0;
}
static inline bool isar_feature_aa32_fp16_dpconv(const ARMISARegisters *id)
{
return FIELD_EX64(id->mvfr1, MVFR1, FPHP) > 1;
}
/*
* 64-bit feature tests via id registers.
*/

3
target/arm/kvm32.c
View File

@ -125,9 +125,6 @@ bool kvm_arm_get_host_cpu_features(ARMHostCPUFeatures *ahcf)
if (extract32(id_pfr0, 12, 4) == 1) {
set_feature(&features, ARM_FEATURE_THUMB2EE);
}
if (extract32(ahcf->isar.mvfr1, 20, 4) == 1) {
set_feature(&features, ARM_FEATURE_VFP_FP16);
}
if (extract32(ahcf->isar.mvfr1, 12, 4) == 1) {
set_feature(&features, ARM_FEATURE_NEON);
}

26
target/arm/translate.c
View File

@ -3663,17 +3663,27 @@ static int disas_vfp_insn(DisasContext *s, uint32_t insn)
* UNPREDICTABLE if bit 8 is set prior to ARMv8
* (we choose to UNDEF)
*/
if ((dp && !arm_dc_feature(s, ARM_FEATURE_V8)) ||
!arm_dc_feature(s, ARM_FEATURE_VFP_FP16)) {
return 1;
if (dp) {
if (!dc_isar_feature(aa32_fp16_dpconv, s)) {
return 1;
}
} else {
if (!dc_isar_feature(aa32_fp16_spconv, s)) {
return 1;
}
}
rm_is_dp = false;
break;
case 0x06: /* vcvtb.f16.f32, vcvtb.f16.f64 */
case 0x07: /* vcvtt.f16.f32, vcvtt.f16.f64 */
if ((dp && !arm_dc_feature(s, ARM_FEATURE_V8)) ||
!arm_dc_feature(s, ARM_FEATURE_VFP_FP16)) {
return 1;
if (dp) {
if (!dc_isar_feature(aa32_fp16_dpconv, s)) {
return 1;
}
} else {
if (!dc_isar_feature(aa32_fp16_spconv, s)) {
return 1;
}
}
rd_is_dp = false;
break;
@ -7876,7 +7886,7 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
TCGv_ptr fpst;
TCGv_i32 ahp;
if (!arm_dc_feature(s, ARM_FEATURE_VFP_FP16) ||
if (!dc_isar_feature(aa32_fp16_spconv, s) ||
q || (rm & 1)) {
return 1;
}
@ -7908,7 +7918,7 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn)
{
TCGv_ptr fpst;
TCGv_i32 ahp;
if (!arm_dc_feature(s, ARM_FEATURE_VFP_FP16) ||
if (!dc_isar_feature(aa32_fp16_spconv, s) ||
q || (rd & 1)) {
return 1;
}