[PATCH 0/2] Fix SIGILL psw.addr reporting

[PATCH 0/2] Fix SIGILL psw.addr reporting

[Ilya Leoshkevich]

qemu-s390x puts a wrong value into SIGILL's siginfo_t's psw.addr: it
should be a pointer to the instruction following the illegal
instruction, but at the moment it is a pointer to the illegal
instruction itself. This breaks OpenJDK, which relies on this value.

Patch 1 fixes the issue, patch 2 adds a test.

Ilya Leoshkevich (2):
  target/s390x: Fix SIGILL psw.addr reporting
  tests/tcg/s390x: Test SIGILL handling

 linux-user/s390x/cpu_loop.c     |  6 ++-
 target/s390x/excp_helper.c      | 69 ++++++++++++++++++---------------
 target/s390x/internal.h         |  1 +
 tests/tcg/s390x/Makefile.target |  1 +
 tests/tcg/s390x/sigill.c        | 41 ++++++++++++++++++++
 5 files changed, 85 insertions(+), 33 deletions(-)
 create mode 100644 tests/tcg/s390x/sigill.c

-- 
2.31.1

[PATCH 1/2] target/s390x: Fix SIGILL psw.addr reporting

[Ilya Leoshkevich]

When a s390x CPU attempts to execute an illegal instruction, an
operation exception is recognized. This is a suppressing exception,
which means that the PSW is advanced by the length of the illegal
instruction.

On the real hardware or in qemu-system-s390x the kernel then raises
SIGILL with si_addr pointing to the suppressed instruction and
psw.addr containing the updated PSW.

Unfortunately qemu-s390x sets both to the address of the suppressed
instruction at the moment. Fix by sharing the PSW advancement logic
with qemu-system-s390x and setting si_addr to the address of the
instruction that raised the exception.

Buglink: https://bugs.launchpad.net/qemu/+bug/1920913
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 linux-user/s390x/cpu_loop.c |  6 +++-
 target/s390x/excp_helper.c  | 69 ++++++++++++++++++++-----------------
 target/s390x/internal.h     |  1 +
 3 files changed, 43 insertions(+), 33 deletions(-)

diff --git a/linux-user/s390x/cpu_loop.c b/linux-user/s390x/cpu_loop.c
index f2d1215fb1..6f5462d4f8 100644
--- a/linux-user/s390x/cpu_loop.c
+++ b/linux-user/s390x/cpu_loop.c
@@ -21,6 +21,7 @@
 #include "qemu-common.h"
 #include "qemu.h"
 #include "cpu_loop-common.h"
+#include "internal.h"
 
 /* s390x masks the fault address it reports in si_addr for SIGSEGV and SIGBUS */
 #define S390X_FAIL_ADDR_MASK -4096LL
@@ -29,6 +30,7 @@ void cpu_loop(CPUS390XState *env)
 {
     CPUState *cs = env_cpu(env);
     int trapnr, n, sig;
+    target_ulong excp_psw_addr;
     target_siginfo_t info;
     target_ulong addr;
     abi_long ret;
@@ -38,6 +40,7 @@ void cpu_loop(CPUS390XState *env)
         trapnr = cpu_exec(cs);
         cpu_exec_end(cs);
         process_queued_cpu_work(cs);
+        excp_psw_addr = env->psw.addr;
 
         switch (trapnr) {
         case EXCP_INTERRUPT:
@@ -66,6 +69,7 @@ void cpu_loop(CPUS390XState *env)
             n = TARGET_TRAP_BRKPT;
             goto do_signal_pc;
         case EXCP_PGM:
+            s390_cpu_program_interrupt_advance_psw(env);
             n = env->int_pgm_code;
             switch (n) {
             case PGM_OPERATION:
@@ -131,7 +135,7 @@ void cpu_loop(CPUS390XState *env)
             break;
 
         do_signal_pc:
-            addr = env->psw.addr;
+            addr = excp_psw_addr;
         do_signal:
             info.si_signo = sig;
             info.si_errno = 0;
diff --git a/target/s390x/excp_helper.c b/target/s390x/excp_helper.c
index 20625c2c8f..0a323967ae 100644
--- a/target/s390x/excp_helper.c
+++ b/target/s390x/excp_helper.c
@@ -82,6 +82,42 @@ void HELPER(data_exception)(CPUS390XState *env, uint32_t dxc)
     tcg_s390_data_exception(env, dxc, GETPC());
 }
 
+void s390_cpu_program_interrupt_advance_psw(CPUS390XState *env)
+{
+    switch (env->int_pgm_code) {
+    case PGM_PER:
+        if (env->per_perc_atmid & PER_CODE_EVENT_NULLIFICATION) {
+            break;
+        }
+        /* FALL THROUGH */
+    case PGM_OPERATION:
+    case PGM_PRIVILEGED:
+    case PGM_EXECUTE:
+    case PGM_PROTECTION:
+    case PGM_ADDRESSING:
+    case PGM_SPECIFICATION:
+    case PGM_DATA:
+    case PGM_FIXPT_OVERFLOW:
+    case PGM_FIXPT_DIVIDE:
+    case PGM_DEC_OVERFLOW:
+    case PGM_DEC_DIVIDE:
+    case PGM_HFP_EXP_OVERFLOW:
+    case PGM_HFP_EXP_UNDERFLOW:
+    case PGM_HFP_SIGNIFICANCE:
+    case PGM_HFP_DIVIDE:
+    case PGM_TRANS_SPEC:
+    case PGM_SPECIAL_OP:
+    case PGM_OPERAND:
+    case PGM_HFP_SQRT:
+    case PGM_PC_TRANS_SPEC:
+    case PGM_ALET_SPEC:
+    case PGM_MONITOR:
+        /* advance the PSW if our exception is not nullifying */
+        env->psw.addr += env->int_pgm_ilen;
+        break;
+    }
+}
+
 #if defined(CONFIG_USER_ONLY)
 
 void s390_cpu_do_interrupt(CPUState *cs)
@@ -202,38 +238,7 @@ static void do_program_interrupt(CPUS390XState *env)
 
     assert(ilen == 2 || ilen == 4 || ilen == 6);
 
-    switch (env->int_pgm_code) {
-    case PGM_PER:
-        if (env->per_perc_atmid & PER_CODE_EVENT_NULLIFICATION) {
-            break;
-        }
-        /* FALL THROUGH */
-    case PGM_OPERATION:
-    case PGM_PRIVILEGED:
-    case PGM_EXECUTE:
-    case PGM_PROTECTION:
-    case PGM_ADDRESSING:
-    case PGM_SPECIFICATION:
-    case PGM_DATA:
-    case PGM_FIXPT_OVERFLOW:
-    case PGM_FIXPT_DIVIDE:
-    case PGM_DEC_OVERFLOW:
-    case PGM_DEC_DIVIDE:
-    case PGM_HFP_EXP_OVERFLOW:
-    case PGM_HFP_EXP_UNDERFLOW:
-    case PGM_HFP_SIGNIFICANCE:
-    case PGM_HFP_DIVIDE:
-    case PGM_TRANS_SPEC:
-    case PGM_SPECIAL_OP:
-    case PGM_OPERAND:
-    case PGM_HFP_SQRT:
-    case PGM_PC_TRANS_SPEC:
-    case PGM_ALET_SPEC:
-    case PGM_MONITOR:
-        /* advance the PSW if our exception is not nullifying */
-        env->psw.addr += ilen;
-        break;
-    }
+    s390_cpu_program_interrupt_advance_psw(env);
 
     qemu_log_mask(CPU_LOG_INT,
                   "%s: code=0x%x ilen=%d psw: %" PRIx64 " %" PRIx64 "\n",
diff --git a/target/s390x/internal.h b/target/s390x/internal.h
index 11515bb617..9f1665ccbf 100644
--- a/target/s390x/internal.h
+++ b/target/s390x/internal.h
@@ -272,6 +272,7 @@ bool s390_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
 void s390x_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
                                    MMUAccessType access_type,
                                    int mmu_idx, uintptr_t retaddr);
+void s390_cpu_program_interrupt_advance_psw(CPUS390XState *cpu);
 
 
 /* fpu_helper.c */
-- 
2.31.1

[PATCH 2/2] tests/tcg/s390x: Test SIGILL handling

[Ilya Leoshkevich]

Verify that s390x-specific uc_mcontext.psw.addr is reported correctly.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 tests/tcg/s390x/Makefile.target |  1 +
 tests/tcg/s390x/sigill.c        | 41 +++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)
 create mode 100644 tests/tcg/s390x/sigill.c

diff --git a/tests/tcg/s390x/Makefile.target b/tests/tcg/s390x/Makefile.target
index 241ef28f61..8699d829a5 100644
--- a/tests/tcg/s390x/Makefile.target
+++ b/tests/tcg/s390x/Makefile.target
@@ -8,3 +8,4 @@ TESTS+=exrl-trtr
 TESTS+=pack
 TESTS+=mvo
 TESTS+=mvc
+TESTS+=sigill
diff --git a/tests/tcg/s390x/sigill.c b/tests/tcg/s390x/sigill.c
new file mode 100644
index 0000000000..f8021dc6af
--- /dev/null
+++ b/tests/tcg/s390x/sigill.c
@@ -0,0 +1,41 @@
+#include <assert.h>
+#include <signal.h>
+#include <string.h>
+#include <ucontext.h>
+#include <unistd.h>
+
+extern char expected_si_addr[];
+extern char expected_psw_addr[];
+
+static void handle_signal(int sig, siginfo_t *info, void *ucontext)
+{
+    if (sig != SIGILL) {
+        _exit(1);
+    }
+
+    if (info->si_addr != expected_si_addr) {
+        _exit(2);
+    }
+
+    if (((ucontext_t *)ucontext)->uc_mcontext.psw.addr !=
+            (unsigned long)expected_psw_addr) {
+        _exit(3);
+    }
+}
+
+int main(void)
+{
+    struct sigaction act;
+
+    memset(&act, 0, sizeof(act));
+    act.sa_sigaction = handle_signal;
+    act.sa_flags = SA_SIGINFO;
+
+    int ret = sigaction(SIGILL, &act, NULL);
+    assert(ret == 0);
+
+    asm volatile("expected_si_addr:\t.byte\t0x00,0x00\n"
+                 "expected_psw_addr:");
+
+    return 0;
+}
-- 
2.31.1

Re: [PATCH 0/2] Fix SIGILL psw.addr reporting

[no-reply]

Patchew URL: https://patchew.org/QEMU/20210521030146.2831663-1-iii@linux.ibm.com/



Hi,

This series seems to have some coding style problems. See output below for
more information:

Type: series
Message-id: 20210521030146.2831663-1-iii@linux.ibm.com
Subject: [PATCH 0/2] Fix SIGILL psw.addr reporting

=== TEST SCRIPT BEGIN ===
#!/bin/bash
git rev-parse base > /dev/null || exit 0
git config --local diff.renamelimit 0
git config --local diff.renames True
git config --local diff.algorithm histogram
./scripts/checkpatch.pl --mailback base..
=== TEST SCRIPT END ===

Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384
From https://github.com/patchew-project/qemu
 * [new tag]         patchew/20210521030146.2831663-1-iii@linux.ibm.com -> patchew/20210521030146.2831663-1-iii@linux.ibm.com
Switched to a new branch 'test'
069d02b tests/tcg/s390x: Test SIGILL handling
a869643 target/s390x: Fix SIGILL psw.addr reporting

=== OUTPUT BEGIN ===
1/2 Checking commit a86964364d4d (target/s390x: Fix SIGILL psw.addr reporting)
2/2 Checking commit 069d02b0edf2 (tests/tcg/s390x: Test SIGILL handling)
WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?
#26: 
new file mode 100644

ERROR: externs should be avoided in .c files
#37: FILE: tests/tcg/s390x/sigill.c:7:
+extern char expected_si_addr[];

ERROR: externs should be avoided in .c files
#38: FILE: tests/tcg/s390x/sigill.c:8:
+extern char expected_psw_addr[];

total: 2 errors, 1 warnings, 45 lines checked

Patch 2/2 has style problems, please review.  If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.

=== OUTPUT END ===

Test command exited with code: 1


The full log is available at
http://patchew.org/logs/20210521030146.2831663-1-iii@linux.ibm.com/testing.checkpatch/?type=message.
---
Email generated automatically by Patchew [https://patchew.org/].
Please send your feedback to patchew-devel@redhat.com

Re: [PATCH 0/2] Fix SIGILL psw.addr reporting

[David Hildenbrand]

On 21.05.21 05:01, Ilya Leoshkevich wrote:
> qemu-s390x puts a wrong value into SIGILL's siginfo_t's psw.addr: it
> should be a pointer to the instruction following the illegal
> instruction, but at the moment it is a pointer to the illegal
> instruction itself. This breaks OpenJDK, which relies on this value.
> 
> Patch 1 fixes the issue, patch 2 adds a test.

I assume that should fix

https://bugs.launchpad.net/qemu/+bug/1920913

right?


-- 
Thanks,

David / dhildenb

Re: [PATCH 1/2] target/s390x: Fix SIGILL psw.addr reporting

[David Hildenbrand]

On 21.05.21 05:01, Ilya Leoshkevich wrote:
> When a s390x CPU attempts to execute an illegal instruction, an
> operation exception is recognized. This is a suppressing exception,
> which means that the PSW is advanced by the length of the illegal
> instruction.
> 
> On the real hardware or in qemu-system-s390x the kernel then raises
> SIGILL with si_addr pointing to the suppressed instruction and
> psw.addr containing the updated PSW.
> 
> Unfortunately qemu-s390x sets both to the address of the suppressed
> instruction at the moment. Fix by sharing the PSW advancement logic
> with qemu-system-s390x and setting si_addr to the address of the
> instruction that raised the exception.
> 
> Buglink: https://bugs.launchpad.net/qemu/+bug/1920913
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
> ---
>   linux-user/s390x/cpu_loop.c |  6 +++-
>   target/s390x/excp_helper.c  | 69 ++++++++++++++++++++-----------------
>   target/s390x/internal.h     |  1 +
>   3 files changed, 43 insertions(+), 33 deletions(-)
> 
> diff --git a/linux-user/s390x/cpu_loop.c b/linux-user/s390x/cpu_loop.c
> index f2d1215fb1..6f5462d4f8 100644
> --- a/linux-user/s390x/cpu_loop.c
> +++ b/linux-user/s390x/cpu_loop.c
> @@ -21,6 +21,7 @@
>   #include "qemu-common.h"
>   #include "qemu.h"
>   #include "cpu_loop-common.h"
> +#include "internal.h"
>   
>   /* s390x masks the fault address it reports in si_addr for SIGSEGV and SIGBUS */
>   #define S390X_FAIL_ADDR_MASK -4096LL
> @@ -29,6 +30,7 @@ void cpu_loop(CPUS390XState *env)
>   {
>       CPUState *cs = env_cpu(env);
>       int trapnr, n, sig;
> +    target_ulong excp_psw_addr;
>       target_siginfo_t info;
>       target_ulong addr;
>       abi_long ret;
> @@ -38,6 +40,7 @@ void cpu_loop(CPUS390XState *env)
>           trapnr = cpu_exec(cs);
>           cpu_exec_end(cs);
>           process_queued_cpu_work(cs);
> +        excp_psw_addr = env->psw.addr;
>   
>           switch (trapnr) {
>           case EXCP_INTERRUPT:
> @@ -66,6 +69,7 @@ void cpu_loop(CPUS390XState *env)
>               n = TARGET_TRAP_BRKPT;
>               goto do_signal_pc;
>           case EXCP_PGM:
> +            s390_cpu_program_interrupt_advance_psw(env);
>               n = env->int_pgm_code;
>               switch (n) {
>               case PGM_OPERATION:
> @@ -131,7 +135,7 @@ void cpu_loop(CPUS390XState *env)
>               break;
>   
>           do_signal_pc:
> -            addr = env->psw.addr;
> +            addr = excp_psw_addr;
>           do_signal:
>               info.si_signo = sig;
>               info.si_errno = 0;
> diff --git a/target/s390x/excp_helper.c b/target/s390x/excp_helper.c
> index 20625c2c8f..0a323967ae 100644
> --- a/target/s390x/excp_helper.c
> +++ b/target/s390x/excp_helper.c
> @@ -82,6 +82,42 @@ void HELPER(data_exception)(CPUS390XState *env, uint32_t dxc)
>       tcg_s390_data_exception(env, dxc, GETPC());
>   }
>   
> +void s390_cpu_program_interrupt_advance_psw(CPUS390XState *env)
> +{
> +    switch (env->int_pgm_code) {
> +    case PGM_PER:
> +        if (env->per_perc_atmid & PER_CODE_EVENT_NULLIFICATION) {
> +            break;
> +        }
> +        /* FALL THROUGH */
> +    case PGM_OPERATION:
> +    case PGM_PRIVILEGED:
> +    case PGM_EXECUTE:
> +    case PGM_PROTECTION:
> +    case PGM_ADDRESSING:
> +    case PGM_SPECIFICATION:
> +    case PGM_DATA:
> +    case PGM_FIXPT_OVERFLOW:
> +    case PGM_FIXPT_DIVIDE:
> +    case PGM_DEC_OVERFLOW:
> +    case PGM_DEC_DIVIDE:
> +    case PGM_HFP_EXP_OVERFLOW:
> +    case PGM_HFP_EXP_UNDERFLOW:
> +    case PGM_HFP_SIGNIFICANCE:
> +    case PGM_HFP_DIVIDE:
> +    case PGM_TRANS_SPEC:
> +    case PGM_SPECIAL_OP:
> +    case PGM_OPERAND:
> +    case PGM_HFP_SQRT:
> +    case PGM_PC_TRANS_SPEC:
> +    case PGM_ALET_SPEC:
> +    case PGM_MONITOR:
> +        /* advance the PSW if our exception is not nullifying */
> +        env->psw.addr += env->int_pgm_ilen;
> +        break;
> +    }
> +}
> +
>   #if defined(CONFIG_USER_ONLY)
>   
>   void s390_cpu_do_interrupt(CPUState *cs)
> @@ -202,38 +238,7 @@ static void do_program_interrupt(CPUS390XState *env)
>   
>       assert(ilen == 2 || ilen == 4 || ilen == 6);
>   
> -    switch (env->int_pgm_code) {
> -    case PGM_PER:
> -        if (env->per_perc_atmid & PER_CODE_EVENT_NULLIFICATION) {
> -            break;
> -        }
> -        /* FALL THROUGH */
> -    case PGM_OPERATION:
> -    case PGM_PRIVILEGED:
> -    case PGM_EXECUTE:
> -    case PGM_PROTECTION:
> -    case PGM_ADDRESSING:
> -    case PGM_SPECIFICATION:
> -    case PGM_DATA:
> -    case PGM_FIXPT_OVERFLOW:
> -    case PGM_FIXPT_DIVIDE:
> -    case PGM_DEC_OVERFLOW:
> -    case PGM_DEC_DIVIDE:
> -    case PGM_HFP_EXP_OVERFLOW:
> -    case PGM_HFP_EXP_UNDERFLOW:
> -    case PGM_HFP_SIGNIFICANCE:
> -    case PGM_HFP_DIVIDE:
> -    case PGM_TRANS_SPEC:
> -    case PGM_SPECIAL_OP:
> -    case PGM_OPERAND:
> -    case PGM_HFP_SQRT:
> -    case PGM_PC_TRANS_SPEC:
> -    case PGM_ALET_SPEC:
> -    case PGM_MONITOR:
> -        /* advance the PSW if our exception is not nullifying */
> -        env->psw.addr += ilen;
> -        break;
> -    }
> +    s390_cpu_program_interrupt_advance_psw(env);
>   
>       qemu_log_mask(CPU_LOG_INT,
>                     "%s: code=0x%x ilen=%d psw: %" PRIx64 " %" PRIx64 "\n",
> diff --git a/target/s390x/internal.h b/target/s390x/internal.h
> index 11515bb617..9f1665ccbf 100644
> --- a/target/s390x/internal.h
> +++ b/target/s390x/internal.h
> @@ -272,6 +272,7 @@ bool s390_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
>   void s390x_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
>                                      MMUAccessType access_type,
>                                      int mmu_idx, uintptr_t retaddr);
> +void s390_cpu_program_interrupt_advance_psw(CPUS390XState *cpu);
>   
>   
>   /* fpu_helper.c */
> 


LGTM, thanks

Reviewed-by: David Hildenbrand <david@redhat.com>

-- 
Thanks,

David / dhildenb

Re: [PATCH 2/2] tests/tcg/s390x: Test SIGILL handling

[David Hildenbrand]

On 21.05.21 05:01, Ilya Leoshkevich wrote:
> Verify that s390x-specific uc_mcontext.psw.addr is reported correctly.
> 
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
> ---
>   tests/tcg/s390x/Makefile.target |  1 +
>   tests/tcg/s390x/sigill.c        | 41 +++++++++++++++++++++++++++++++++
>   2 files changed, 42 insertions(+)
>   create mode 100644 tests/tcg/s390x/sigill.c
> 
> diff --git a/tests/tcg/s390x/Makefile.target b/tests/tcg/s390x/Makefile.target
> index 241ef28f61..8699d829a5 100644
> --- a/tests/tcg/s390x/Makefile.target
> +++ b/tests/tcg/s390x/Makefile.target
> @@ -8,3 +8,4 @@ TESTS+=exrl-trtr
>   TESTS+=pack
>   TESTS+=mvo
>   TESTS+=mvc
> +TESTS+=sigill
> diff --git a/tests/tcg/s390x/sigill.c b/tests/tcg/s390x/sigill.c
> new file mode 100644
> index 0000000000..f8021dc6af
> --- /dev/null
> +++ b/tests/tcg/s390x/sigill.c
> @@ -0,0 +1,41 @@
> +#include <assert.h>
> +#include <signal.h>
> +#include <string.h>
> +#include <ucontext.h>
> +#include <unistd.h>
> +
> +extern char expected_si_addr[];
> +extern char expected_psw_addr[];

Why "extern" ? For the magic inline asm below to work?

> +
> +static void handle_signal(int sig, siginfo_t *info, void *ucontext)
> +{
> +    if (sig != SIGILL) {
> +        _exit(1);
> +    }
> +
> +    if (info->si_addr != expected_si_addr) {
> +        _exit(2);
> +    }
> +
> +    if (((ucontext_t *)ucontext)->uc_mcontext.psw.addr !=
> +            (unsigned long)expected_psw_addr) {
> +        _exit(3);
> +    }
> +}
> +
> +int main(void)
> +{
> +    struct sigaction act;
> +
> +    memset(&act, 0, sizeof(act));
> +    act.sa_sigaction = handle_signal;
> +    act.sa_flags = SA_SIGINFO;
> +
> +    int ret = sigaction(SIGILL, &act, NULL);

Mixing code and declaration.

> +    assert(ret == 0);
> +
> +    asm volatile("expected_si_addr:\t.byte\t0x00,0x00\n"
> +                 "expected_psw_addr:");

At least I am confused how the right values actually end up in 
expected_si_addr and expected_psw_addr.

Can we maybe add a comment? This looks quite hacky ;)

-- 
Thanks,

David / dhildenb

Re: [PATCH 2/2] tests/tcg/s390x: Test SIGILL handling

[Ilya Leoshkevich]

On Fri, 2021-05-21 at 09:54 +0200, David Hildenbrand wrote:
> On 21.05.21 05:01, Ilya Leoshkevich wrote:
> > Verify that s390x-specific uc_mcontext.psw.addr is reported
> > correctly.
> > 
> > Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
> > ---
> >   tests/tcg/s390x/Makefile.target |  1 +
> >   tests/tcg/s390x/sigill.c        | 41
> > +++++++++++++++++++++++++++++++++
> >   2 files changed, 42 insertions(+)
> >   create mode 100644 tests/tcg/s390x/sigill.c
> > 
> > diff --git a/tests/tcg/s390x/Makefile.target
> > b/tests/tcg/s390x/Makefile.target
> > index 241ef28f61..8699d829a5 100644
> > --- a/tests/tcg/s390x/Makefile.target
> > +++ b/tests/tcg/s390x/Makefile.target
> > @@ -8,3 +8,4 @@ TESTS+=exrl-trtr
> >   TESTS+=pack
> >   TESTS+=mvo
> >   TESTS+=mvc
> > +TESTS+=sigill
> > diff --git a/tests/tcg/s390x/sigill.c b/tests/tcg/s390x/sigill.c
> > new file mode 100644
> > index 0000000000..f8021dc6af
> > --- /dev/null
> > +++ b/tests/tcg/s390x/sigill.c
> > @@ -0,0 +1,41 @@
> > +#include <assert.h>
> > +#include <signal.h>
> > +#include <string.h>
> > +#include <ucontext.h>
> > +#include <unistd.h>
> > +
> > +extern char expected_si_addr[];
> > +extern char expected_psw_addr[];
> 
> Why "extern" ? For the magic inline asm below to work?

Yes - it cannot be static, because AFAIK there is no such thing as
static variable declaration (one can only define static variables).

> > +
> > +static void handle_signal(int sig, siginfo_t *info, void
> > *ucontext)
> > +{
> > +    if (sig != SIGILL) {
> > +        _exit(1);
> > +    }
> > +
> > +    if (info->si_addr != expected_si_addr) {
> > +        _exit(2);
> > +    }
> > +
> > +    if (((ucontext_t *)ucontext)->uc_mcontext.psw.addr !=
> > +            (unsigned long)expected_psw_addr) {
> > +        _exit(3);
> > +    }
> > +}
> > +
> > +int main(void)
> > +{
> > +    struct sigaction act;
> > +
> > +    memset(&act, 0, sizeof(act));
> > +    act.sa_sigaction = handle_signal;
> > +    act.sa_flags = SA_SIGINFO;
> > +
> > +    int ret = sigaction(SIGILL, &act, NULL);
> 
> Mixing code and declaration.

Ouch, will fix.

> > +    assert(ret == 0);
> > +
> > +    asm volatile("expected_si_addr:\t.byte\t0x00,0x00\n"
> > +                 "expected_psw_addr:");
> 
> At least I am confused how the right values actually end up in 
> expected_si_addr and expected_psw_addr.
> 
> Can we maybe add a comment? This looks quite hacky ;)

This whole construction is roughly the same as having sigill.s file
with:

.globl expected_si_addr
expected_si_addr: .byte 0,0
.globl expected_psw_addr
expected_psw_addr: br 14

and sigill.h file with:

void expected_si_addr(void);
extern char expected_psw_addr[];

Doing it this way would complicate the build, so I thought it would be
better to just put everything into a single file.

Re: [PATCH 0/2] Fix SIGILL psw.addr reporting

[Ilya Leoshkevich]

On Fri, 2021-05-21 at 09:42 +0200, David Hildenbrand wrote:
> On 21.05.21 05:01, Ilya Leoshkevich wrote:
> > qemu-s390x puts a wrong value into SIGILL's siginfo_t's psw.addr:
> > it
> > should be a pointer to the instruction following the illegal
> > instruction, but at the moment it is a pointer to the illegal
> > instruction itself. This breaks OpenJDK, which relies on this
> > value.
> > 
> > Patch 1 fixes the issue, patch 2 adds a test.
> 
> I assume that should fix
> 
> https://bugs.launchpad.net/qemu/+bug/1920913
> 
> right?

Yes, I have this Buglink in the fix commit message.
I have to admit I did not test Java more extensively - there might be
more things going on - but at least with this the SIGILL on startup is
gone, and very simple programs work.

Re: [PATCH 0/2] Fix SIGILL psw.addr reporting

[Cornelia Huck]

On Fri, 21 May 2021 12:45:30 +0200
Ilya Leoshkevich <iii@linux.ibm.com> wrote:

> On Fri, 2021-05-21 at 09:42 +0200, David Hildenbrand wrote:
> > On 21.05.21 05:01, Ilya Leoshkevich wrote:  
> > > qemu-s390x puts a wrong value into SIGILL's siginfo_t's psw.addr:
> > > it
> > > should be a pointer to the instruction following the illegal
> > > instruction, but at the moment it is a pointer to the illegal
> > > instruction itself. This breaks OpenJDK, which relies on this
> > > value.
> > > 
> > > Patch 1 fixes the issue, patch 2 adds a test.  
> > 
> > I assume that should fix
> > 
> > https://bugs.launchpad.net/qemu/+bug/1920913
> > 
> > right?  
> 
> Yes, I have this Buglink in the fix commit message.

Better add https://gitlab.com/qemu-project/qemu/-/issues/319 as the
Buglink :)

> I have to admit I did not test Java more extensively - there might be
> more things going on - but at least with this the SIGILL on startup is
> gone, and very simple programs work.
> 
>