[PATCH 0/2] linux-user/aarch64: Syndrome fixes and enhancements

[PATCH 0/2] linux-user/aarch64: Syndrome fixes and enhancements

[Richard Henderson]

The first patch is a true bug fix versus the si_code of some SIGILL.
The second patch is new feature, adding the ESR record to the frame.


r~


Richard Henderson (2):
  linux-user/aarch64: Check syndrome for EXCP_UDEF
  linux-user/aarch64: Generate ESR signal records

 linux-user/aarch64/cpu_loop.c | 20 +++++++++++++++++---
 linux-user/aarch64/signal.c   | 34 +++++++++++++++++++++++++++++++++-
 2 files changed, 50 insertions(+), 4 deletions(-)

-- 
2.43.0

[PATCH for-10.1 1/2] linux-user/aarch64: Check syndrome for EXCP_UDEF

[Richard Henderson]

Note that we have been passing the incorrect code for
uncategorized and bti faults.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/aarch64/cpu_loop.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/linux-user/aarch64/cpu_loop.c b/linux-user/aarch64/cpu_loop.c
index fea43cefa6..43a471b535 100644
--- a/linux-user/aarch64/cpu_loop.c
+++ b/linux-user/aarch64/cpu_loop.c
@@ -32,6 +32,7 @@ void cpu_loop(CPUARMState *env)
 {
     CPUState *cs = env_cpu(env);
     int trapnr, ec, fsc, si_code, si_signo;
+    uint64_t addr;
     abi_long ret;
 
     for (;;) {
@@ -63,10 +64,12 @@ void cpu_loop(CPUARMState *env)
             /* just indicate that signals should be handled asap */
             break;
         case EXCP_UDEF:
-            force_sig_fault(TARGET_SIGILL, TARGET_ILL_ILLOPN, env->pc);
-            break;
+            addr = env->pc;
+            goto do_syndrome;
         case EXCP_PREFETCH_ABORT:
         case EXCP_DATA_ABORT:
+            addr = env->exception.vaddress;
+        do_syndrome:
             ec = syn_get_ec(env->exception.syndrome);
             switch (ec) {
             case EC_DATAABORT:
@@ -99,10 +102,19 @@ void cpu_loop(CPUARMState *env)
                 si_signo = TARGET_SIGBUS;
                 si_code = TARGET_BUS_ADRALN;
                 break;
+            case EC_UNCATEGORIZED:
+            case EC_BTITRAP:
+                si_signo = TARGET_SIGILL;
+                si_code = TARGET_ILL_ILLOPC;
+                break;
+            case EC_PACFAIL:
+                si_signo = TARGET_SIGILL;
+                si_code = TARGET_ILL_ILLOPN;
+                break;
             default:
                 g_assert_not_reached();
             }
-            force_sig_fault(si_signo, si_code, env->exception.vaddress);
+            force_sig_fault(si_signo, si_code, addr);
             break;
         case EXCP_DEBUG:
         case EXCP_BKPT:
-- 
2.43.0

[PATCH for-10.2? 2/2] linux-user/aarch64: Generate ESR signal records

[Richard Henderson]

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/aarch64/cpu_loop.c |  2 ++
 linux-user/aarch64/signal.c   | 34 +++++++++++++++++++++++++++++++++-
 2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/linux-user/aarch64/cpu_loop.c b/linux-user/aarch64/cpu_loop.c
index 43a471b535..a290dda30c 100644
--- a/linux-user/aarch64/cpu_loop.c
+++ b/linux-user/aarch64/cpu_loop.c
@@ -70,6 +70,8 @@ void cpu_loop(CPUARMState *env)
         case EXCP_DATA_ABORT:
             addr = env->exception.vaddress;
         do_syndrome:
+            /* Let signal delivery see that ESR is live. */
+            env->cp15.esr_el[1] = env->exception.syndrome;
             ec = syn_get_ec(env->exception.syndrome);
             switch (ec) {
             case EC_DATAABORT:
diff --git a/linux-user/aarch64/signal.c b/linux-user/aarch64/signal.c
index d50cab78d8..ca46734e2d 100644
--- a/linux-user/aarch64/signal.c
+++ b/linux-user/aarch64/signal.c
@@ -65,6 +65,13 @@ struct target_fpsimd_context {
     uint64_t vregs[32 * 2]; /* really uint128_t vregs[32] */
 };
 
+#define TARGET_ESR_MAGIC    0x45535201
+
+struct target_esr_context {
+    struct target_aarch64_ctx head;
+    uint64_t esr;
+};
+
 #define TARGET_EXTRA_MAGIC  0x45585401
 
 struct target_extra_context {
@@ -177,6 +184,14 @@ static void target_setup_fpsimd_record(struct target_fpsimd_context *fpsimd,
     }
 }
 
+static void target_setup_esr_record(struct target_esr_context *ctx,
+                                    CPUARMState *env)
+{
+    __put_user(TARGET_ESR_MAGIC, &ctx->head.magic);
+    __put_user(sizeof(*ctx), &ctx->head.size);
+    __put_user(env->cp15.esr_el[1], &ctx->esr);
+}
+
 static void target_setup_extra_record(struct target_extra_context *extra,
                                       uint64_t datap, uint32_t extra_size)
 {
@@ -444,6 +459,9 @@ static int target_restore_sigframe(CPUARMState *env,
             fpsimd = (struct target_fpsimd_context *)ctx;
             break;
 
+        case TARGET_ESR_MAGIC:
+            break; /* ignore */
+
         case TARGET_SVE_MAGIC:
             if (sve || size < sizeof(struct target_sve_context)) {
                 goto err;
@@ -568,7 +586,7 @@ static void target_setup_frame(int usig, struct target_sigaction *ka,
         .total_size = offsetof(struct target_rt_sigframe,
                                uc.tuc_mcontext.__reserved),
     };
-    int fpsimd_ofs, fr_ofs, sve_ofs = 0, za_ofs = 0;
+    int fpsimd_ofs, fr_ofs, esr_ofs = 0, sve_ofs = 0, za_ofs = 0;
     int sve_size = 0, za_size = 0;
     struct target_rt_sigframe *frame;
     struct target_rt_frame_record *fr;
@@ -578,6 +596,15 @@ static void target_setup_frame(int usig, struct target_sigaction *ka,
     fpsimd_ofs = alloc_sigframe_space(sizeof(struct target_fpsimd_context),
                                       &layout);
 
+    /*
+     * In user mode, ESR_EL1 is only set by cpu_loop while queueing the
+     * signal, and it's only valid for the one sync insn.
+     */
+    if (env->cp15.esr_el[1]) {
+        esr_ofs = alloc_sigframe_space(sizeof(struct target_esr_context),
+                                       &layout);
+    }
+
     /* SVE state needs saving only if it exists.  */
     if (cpu_isar_feature(aa64_sve, env_archcpu(env)) ||
         cpu_isar_feature(aa64_sme, env_archcpu(env))) {
@@ -631,6 +658,11 @@ static void target_setup_frame(int usig, struct target_sigaction *ka,
 
     target_setup_general_frame(frame, env, set);
     target_setup_fpsimd_record((void *)frame + fpsimd_ofs, env);
+    if (esr_ofs) {
+        target_setup_esr_record((void *)frame + esr_ofs, env);
+        /* Leave ESR_EL1 clear while it's not relevant. */
+        env->cp15.esr_el[1] = 0;
+    }
     target_setup_end_record((void *)frame + layout.std_end_ofs);
     if (layout.extra_ofs) {
         target_setup_extra_record((void *)frame + layout.extra_ofs,
-- 
2.43.0

Re: [PATCH for-10.1 1/2] linux-user/aarch64: Check syndrome for EXCP_UDEF

[Pierrick Bouvier]

On 7/25/25 9:51 AM, Richard Henderson wrote:
> Note that we have been passing the incorrect code for
> uncategorized and bti faults.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   linux-user/aarch64/cpu_loop.c | 18 +++++++++++++++---
>   1 file changed, 15 insertions(+), 3 deletions(-)
> 
> diff --git a/linux-user/aarch64/cpu_loop.c b/linux-user/aarch64/cpu_loop.c
> index fea43cefa6..43a471b535 100644
> --- a/linux-user/aarch64/cpu_loop.c
> +++ b/linux-user/aarch64/cpu_loop.c
> @@ -32,6 +32,7 @@ void cpu_loop(CPUARMState *env)
>   {
>       CPUState *cs = env_cpu(env);
>       int trapnr, ec, fsc, si_code, si_signo;
> +    uint64_t addr;
>       abi_long ret;
>   
>       for (;;) {
> @@ -63,10 +64,12 @@ void cpu_loop(CPUARMState *env)
>               /* just indicate that signals should be handled asap */
>               break;
>           case EXCP_UDEF:
> -            force_sig_fault(TARGET_SIGILL, TARGET_ILL_ILLOPN, env->pc);
> -            break;
> +            addr = env->pc;
> +            goto do_syndrome;
>           case EXCP_PREFETCH_ABORT:
>           case EXCP_DATA_ABORT:
> +            addr = env->exception.vaddress;
> +        do_syndrome:
>               ec = syn_get_ec(env->exception.syndrome);
>               switch (ec) {
>               case EC_DATAABORT:
> @@ -99,10 +102,19 @@ void cpu_loop(CPUARMState *env)
>                   si_signo = TARGET_SIGBUS;
>                   si_code = TARGET_BUS_ADRALN;
>                   break;
> +            case EC_UNCATEGORIZED:
> +            case EC_BTITRAP:
> +                si_signo = TARGET_SIGILL;
> +                si_code = TARGET_ILL_ILLOPC;
> +                break;
> +            case EC_PACFAIL:
> +                si_signo = TARGET_SIGILL;
> +                si_code = TARGET_ILL_ILLOPN;
> +                break;
>               default:
>                   g_assert_not_reached();
>               }
> -            force_sig_fault(si_signo, si_code, env->exception.vaddress);
> +            force_sig_fault(si_signo, si_code, addr);
>               break;
>           case EXCP_DEBUG:
>           case EXCP_BKPT:

It may be worth for lisibility to extract do_syndrome to a proper 
function. It's just a recommendation though.

Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>

Re: [PATCH for-10.2? 2/2] linux-user/aarch64: Generate ESR signal records

[Pierrick Bouvier]

On 7/25/25 9:51 AM, Richard Henderson wrote:
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   linux-user/aarch64/cpu_loop.c |  2 ++
>   linux-user/aarch64/signal.c   | 34 +++++++++++++++++++++++++++++++++-
>   2 files changed, 35 insertions(+), 1 deletion(-)

Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>