sparc/syscall: fix syscall_get_arch

Sparc's syscall_get_arch was buggy: it returned the task arch, not the
syscall arch.  This could confuse seccomp and audit.

I don't think this is as bad for seccomp as it looks: sparc's 32-bit and
64-bit syscalls are numbered the same.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/sparc/include/asm/syscall.h

@@ -3,6 +3,7 @@
 
 #include <uapi/linux/audit.h>
 #include <linux/kernel.h>
+#include <linux/compat.h>
 #include <linux/sched.h>
 #include <asm/ptrace.h>
 #include <asm/thread_info.h>
@@ -128,7 +129,13 @@ static inline void syscall_set_arguments(struct task_struct *task,
 
 static inline int syscall_get_arch(void)
 {
-	return is_32bit_task() ? AUDIT_ARCH_SPARC : AUDIT_ARCH_SPARC64;
+#if defined(CONFIG_SPARC64) && defined(CONFIG_COMPAT)
+	return in_compat_syscall() ? AUDIT_ARCH_SPARC : AUDIT_ARCH_SPARC64;
+#elif defined(CONFIG_SPARC64)
+	return AUDIT_ARCH_SPARC64;
+#else
+	return AUDIT_ARCH_SPARC;
+#endif
 }
 
 #endif /* __ASM_SPARC_SYSCALL_H */