Move arm_reset_sve_state() calls to aarch64_set_svcr().

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20230112102436.1913-5-philmd@linaro.org
Message-Id: <20230112004322.161330-1-richard.henderson@linaro.org>
[PMD: Split patch in multiple tiny steps]
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
(cherry picked from commit 7f2a01e7368f960fadea38f437d0f6de7f249686)
---
 target/arm/cpu.h              |  1 -
 linux-user/aarch64/cpu_loop.c |  1 -
 linux-user/aarch64/signal.c   |  8 +-------
 target/arm/helper.c           | 13 +++++++++++++
 target/arm/sme_helper.c       | 10 ----------
 5 files changed, 14 insertions(+), 19 deletions(-)

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index 8acfd3af4c..02a084c962 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -1119,7 +1119,6 @@ void aarch64_sve_narrow_vq(CPUARMState *env, unsigned vq);
 void aarch64_sve_change_el(CPUARMState *env, int old_el,
                            int new_el, bool el0_a64);
 void aarch64_set_svcr(CPUARMState *env, uint64_t new, uint64_t mask);
-void arm_reset_sve_state(CPUARMState *env);
 
 /*
  * SVE registers are encoded in KVM's memory in an endianness-invariant format.
diff --git a/linux-user/aarch64/cpu_loop.c b/linux-user/aarch64/cpu_loop.c
index d53742e10b..5e93d27d8f 100644
--- a/linux-user/aarch64/cpu_loop.c
+++ b/linux-user/aarch64/cpu_loop.c
@@ -96,7 +96,6 @@ void cpu_loop(CPUARMState *env)
             aarch64_set_svcr(env, 0, R_SVCR_SM_MASK);
             if (FIELD_EX64(env->svcr, SVCR, SM)) {
                 arm_rebuild_hflags(env);
-                arm_reset_sve_state(env);
             }
             ret = do_syscall(env,
                              env->xregs[8],
diff --git a/linux-user/aarch64/signal.c b/linux-user/aarch64/signal.c
index b6e4dcb494..a326a6def5 100644
--- a/linux-user/aarch64/signal.c
+++ b/linux-user/aarch64/signal.c
@@ -665,14 +665,8 @@ static void target_setup_frame(int usig, struct target_sigaction *ka,
         env->btype = 2;
     }
 
-    /*
-     * Invoke the signal handler with both SM and ZA disabled.
-     * When clearing SM, ResetSVEState, per SMSTOP.
-     */
+    /* Invoke the signal handler with both SM and ZA disabled. */
     aarch64_set_svcr(env, 0, R_SVCR_SM_MASK | R_SVCR_ZA_MASK);
-    if (FIELD_EX64(env->svcr, SVCR, SM)) {
-        arm_reset_sve_state(env);
-    }
     if (env->svcr) {
         arm_rebuild_hflags(env);
     }
diff --git a/target/arm/helper.c b/target/arm/helper.c
index 86b97daf7e..94a6f431a9 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -6429,11 +6429,24 @@ static CPAccessResult access_esm(CPUARMState *env, const ARMCPRegInfo *ri,
     return CP_ACCESS_OK;
 }
 
+/* ResetSVEState */
+static void arm_reset_sve_state(CPUARMState *env)
+{
+    memset(env->vfp.zregs, 0, sizeof(env->vfp.zregs));
+    /* Recall that FFR is stored as pregs[16]. */
+    memset(env->vfp.pregs, 0, sizeof(env->vfp.pregs));
+    vfp_set_fpcr(env, 0x0800009f);
+}
+
 void aarch64_set_svcr(CPUARMState *env, uint64_t new, uint64_t mask)
 {
     uint64_t change = (env->svcr ^ new) & mask;
 
     env->svcr ^= change;
+
+    if (change & R_SVCR_SM_MASK) {
+        arm_reset_sve_state(env);
+    }
 }
 
 static void svcr_write(CPUARMState *env, const ARMCPRegInfo *ri,
diff --git a/target/arm/sme_helper.c b/target/arm/sme_helper.c
index 7717dab64f..56a8fbe691 100644
--- a/target/arm/sme_helper.c
+++ b/target/arm/sme_helper.c
@@ -29,22 +29,12 @@
 #include "vec_internal.h"
 #include "sve_ldst_internal.h"
 
-/* ResetSVEState */
-void arm_reset_sve_state(CPUARMState *env)
-{
-    memset(env->vfp.zregs, 0, sizeof(env->vfp.zregs));
-    /* Recall that FFR is stored as pregs[16]. */
-    memset(env->vfp.pregs, 0, sizeof(env->vfp.pregs));
-    vfp_set_fpsr(env, 0x0800009f);
-}
-
 void helper_set_pstate_sm(CPUARMState *env, uint32_t i)
 {
     if (i == FIELD_EX64(env->svcr, SVCR, SM)) {
         return;
     }
     aarch64_set_svcr(env, 0, R_SVCR_SM_MASK);
-    arm_reset_sve_state(env);
     arm_rebuild_hflags(env);
 }
 
-- 
2.43.0

On 28.07.2025 21:16, Richard Henderson wrote:
> Move arm_reset_sve_state() calls to aarch64_set_svcr().
> (cherry picked from commit 7f2a01e7368f960fadea38f437d0f6de7f249686)

> +/* ResetSVEState */
> +static void arm_reset_sve_state(CPUARMState *env)
> +{
> +    memset(env->vfp.zregs, 0, sizeof(env->vfp.zregs));
> +    /* Recall that FFR is stored as pregs[16]. */
> +    memset(env->vfp.pregs, 0, sizeof(env->vfp.pregs));
> +    vfp_set_fpcr(env, 0x0800009f);
> +}

> -/* ResetSVEState */
> -void arm_reset_sve_state(CPUARMState *env)
> -{
> -    memset(env->vfp.zregs, 0, sizeof(env->vfp.zregs));
> -    /* Recall that FFR is stored as pregs[16]. */
> -    memset(env->vfp.pregs, 0, sizeof(env->vfp.pregs));
> -    vfp_set_fpsr(env, 0x0800009f);
> -}

It's a fun one.  Please note vfp_set_fpsr vs vfp_set_fpcr.

cf. 1edc3d43f20df0d04f8d00b906ba19fed37512a5 which has been
back-ported to 7.2 already :)

Unfortunately the order of these commits is different than
the one on master.

/mjt

On 7/28/25 09:43, Michael Tokarev wrote:
> On 28.07.2025 21:16, Richard Henderson wrote:
>> Move arm_reset_sve_state() calls to aarch64_set_svcr().
>> (cherry picked from commit 7f2a01e7368f960fadea38f437d0f6de7f249686)
> 
>> +/* ResetSVEState */
>> +static void arm_reset_sve_state(CPUARMState *env)
>> +{
>> +    memset(env->vfp.zregs, 0, sizeof(env->vfp.zregs));
>> +    /* Recall that FFR is stored as pregs[16]. */
>> +    memset(env->vfp.pregs, 0, sizeof(env->vfp.pregs));
>> +    vfp_set_fpcr(env, 0x0800009f);
>> +}
> 
>> -/* ResetSVEState */
>> -void arm_reset_sve_state(CPUARMState *env)
>> -{
>> -    memset(env->vfp.zregs, 0, sizeof(env->vfp.zregs));
>> -    /* Recall that FFR is stored as pregs[16]. */
>> -    memset(env->vfp.pregs, 0, sizeof(env->vfp.pregs));
>> -    vfp_set_fpsr(env, 0x0800009f);
>> -}
> 
> It's a fun one.  Please note vfp_set_fpsr vs vfp_set_fpcr.
> 
> cf. 1edc3d43f20df0d04f8d00b906ba19fed37512a5 which has been
> back-ported to 7.2 already :)
> 
> Unfortunately the order of these commits is different than
> the one on master.
> 
> /mjt

Oh, whoops!  Thanks for the catch!


r~