[Qemu-devel] [PATCH 4/4] linux-user: Handle rt_sigaction correctly for SPARC

[Peter Maydell <peter.maydell@linaro.org>]

SPARC is like Alpha in its handling of the rt_sigaction syscall:
it takes an extra parameter 'restorer' which needs to be copied
into the sa_restorer field of the sigaction struct. The order
of the arguments differs slightly between SPARC and Alpha but
the implementation is otherwise the same. (Compare the
rt_sigaction() functions in arch/sparc/kernel/sys_sparc_64.c
and arch/alpha/kernel/signal.c.)

Note that this change is somewhat moot until SPARC acquires
support for actually delivering RT signals.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 linux-user/syscall.c | 27 +++++++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index d4497de..8beab51 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -8556,8 +8556,16 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
     case TARGET_NR_rt_sigaction:
         {
 #if defined(TARGET_ALPHA)
-            struct target_sigaction act, oact, *pact = 0;
+            /* For Alpha and SPARC this is a 5 argument syscall, with
+             * a 'restorer' parameter which must be copied into the
+             * sa_restorer field of the sigaction struct.
+             * For Alpha that 'restorer' is arg5; for SPARC it is arg4,
+             * and arg5 is the sigsetsize.
+             * Alpha also has a separate rt_sigaction struct that it uses
+             * here; SPARC uses the usual sigaction struct.
+             */
             struct target_rt_sigaction *rt_act;
+            struct target_sigaction act, oact, *pact = 0;
 
             if (arg4 != sizeof(target_sigset_t)) {
                 ret = -TARGET_EINVAL;
@@ -8583,18 +8591,29 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1,
                 unlock_user_struct(rt_act, arg3, 1);
             }
 #else
+#ifdef TARGET_SPARC
+            target_ulong restorer = arg4;
+            target_ulong sigsetsize = arg5;
+#else
+            target_ulong sigsetsize = arg4;
+#endif
             struct target_sigaction *act;
             struct target_sigaction *oact;
 
-            if (arg4 != sizeof(target_sigset_t)) {
+            if (sigsetsize != sizeof(target_sigset_t)) {
                 ret = -TARGET_EINVAL;
                 break;
             }
             if (arg2) {
-                if (!lock_user_struct(VERIFY_READ, act, arg2, 1))
+                if (!lock_user_struct(VERIFY_READ, act, arg2, 1)) {
                     goto efault;
-            } else
+                }
+#ifdef TARGET_SPARC
+                act->sa_restorer = restorer;
+#endif
+            } else {
                 act = NULL;
+            }
             if (arg3) {
                 if (!lock_user_struct(VERIFY_WRITE, oact, arg3, 0)) {
                     ret = -TARGET_EFAULT;
-- 
2.7.4