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[PATCH v3 07/15] target/arm: Remove fp checks from sve_exception_el
From: |
Richard Henderson |
Subject: |
[PATCH v3 07/15] target/arm: Remove fp checks from sve_exception_el |
Date: |
Fri, 27 May 2022 11:06:15 -0700 |
Instead of checking these bits in fp_exception_el and
also in sve_exception_el, document that we must compare
the results. The only place where we have not already
checked that FP EL is zero is in rebuild_hflags_a64.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
target/arm/helper.c | 56 +++++++++++++++------------------------------
1 file changed, 19 insertions(+), 37 deletions(-)
diff --git a/target/arm/helper.c b/target/arm/helper.c
index 84cb78d151..cd0a8992ba 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -6135,11 +6135,15 @@ static const ARMCPRegInfo minimal_ras_reginfo[] = {
.access = PL2_RW, .fieldoffset = offsetof(CPUARMState, cp15.vsesr_el2) },
};
-/* Return the exception level to which exceptions should be taken
- * via SVEAccessTrap. If an exception should be routed through
- * AArch64.AdvSIMDFPAccessTrap, return 0; fp_exception_el should
- * take care of raising that exception.
- * C.f. the ARM pseudocode function CheckSVEEnabled.
+/*
+ * Return the exception level to which exceptions should be taken
+ * via SVEAccessTrap. This excludes the check for whether the exception
+ * should be routed through AArch64.AdvSIMDFPAccessTrap. That can easily
+ * be found by testing 0 < fp_exception_el < sve_exception_el.
+ *
+ * C.f. the ARM pseudocode function CheckSVEEnabled. Note that the
+ * pseudocode does *not* separate out the FP trap checks, but has them
+ * all in one function.
*/
int sve_exception_el(CPUARMState *env, int el)
{
@@ -6157,18 +6161,6 @@ int sve_exception_el(CPUARMState *env, int el)
case 2:
return 1;
}
-
- /* Check CPACR.FPEN. */
- switch (FIELD_EX64(env->cp15.cpacr_el1, CPACR_EL1, FPEN)) {
- case 1:
- if (el != 0) {
- break;
- }
- /* fall through */
- case 0:
- case 2:
- return 0;
- }
}
/*
@@ -6186,24 +6178,10 @@ int sve_exception_el(CPUARMState *env, int el)
case 2:
return 2;
}
-
- switch (FIELD_EX32(env->cp15.cptr_el[2], CPTR_EL2, FPEN)) {
- case 1:
- if (el == 2 || !(hcr_el2 & HCR_TGE)) {
- break;
- }
- /* fall through */
- case 0:
- case 2:
- return 0;
- }
} else if (arm_is_el2_enabled(env)) {
if (FIELD_EX64(env->cp15.cptr_el[2], CPTR_EL2, TZ)) {
return 2;
}
- if (FIELD_EX64(env->cp15.cptr_el[2], CPTR_EL2, TFP)) {
- return 0;
- }
}
}
@@ -13658,15 +13636,19 @@ static CPUARMTBFlags rebuild_hflags_a64(CPUARMState
*env, int el, int fp_el,
if (cpu_isar_feature(aa64_sve, env_archcpu(env))) {
int sve_el = sve_exception_el(env, el);
- uint32_t zcr_len;
+ uint32_t zcr_len = 0;
/*
- * If SVE is disabled, but FP is enabled,
- * then the effective len is 0.
+ * If either FP or SVE are disabled, translator does not need len.
+ * If SVE EL > FP EL, FP exception has precedence, and translator
+ * does not need SVE EL. Save potential re-translations by forcing
+ * the unneeded data to zero.
*/
- if (sve_el != 0 && fp_el == 0) {
- zcr_len = 0;
- } else {
+ if (fp_el != 0) {
+ if (sve_el > fp_el) {
+ sve_el = 0;
+ }
+ } else if (sve_el == 0) {
zcr_len = sve_vqm1_for_el(env, el);
}
DP_TBFLAG_A64(flags, SVEEXC_EL, sve_el);
--
2.34.1
- Re: [PATCH v3 08/15] target/arm: Add el_is_in_host, (continued)
- [PATCH v3 09/15] target/arm: Use el_is_in_host for sve_vqm1_for_el, Richard Henderson, 2022/05/27
- [PATCH v3 10/15] target/arm: Split out load/store primitives to sve_ldst_internal.h, Richard Henderson, 2022/05/27
- [PATCH v3 12/15] target/arm: Move expand_pred_b to vec_internal.h, Richard Henderson, 2022/05/27
- [PATCH v3 05/15] target/arm: Use uint32_t instead of bitmap for sve vq's, Richard Henderson, 2022/05/27
- [PATCH v3 13/15] target/arm: Use expand_pred_b in mve_helper.c, Richard Henderson, 2022/05/27
- [PATCH v3 07/15] target/arm: Remove fp checks from sve_exception_el,
Richard Henderson <=
- [PATCH v3 15/15] target/arm: Export bfdotadd from vec_helper.c, Richard Henderson, 2022/05/27
- [PATCH v3 14/15] target/arm: Move expand_pred_h to vec_internal.h, Richard Henderson, 2022/05/27
- [PATCH v3 11/15] target/arm: Export sve contiguous ldst support functions, Richard Henderson, 2022/05/27
- [PATCH v3 04/15] target/arm: Merge aarch64_sve_zcr_get_valid_len into caller, Richard Henderson, 2022/05/27