signal: refactor copy_siginfo_to_user32
Factor out a copy_siginfo_to_external32 helper from
copy_siginfo_to_user32 that fills out the compat_siginfo, but does so
on a kernel space data structure. With that we can let architectures
override copy_siginfo_to_user32 with their own implementations using
copy_siginfo_to_external32. That allows moving the x32 SIGCHLD purely
to x86 architecture code.
As a nice side effect copy_siginfo_to_external32 also comes in handy
for avoiding a set_fs() call in the coredump code later on.
Contains improvements from Eric W. Biederman <ebiederm@xmission.com>
and Arnd Bergmann <arnd@arndb.de>.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index f9d8804..81cf223 100644
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -350,7 +350,7 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
unsafe_put_user(*(__u64 *)set, (__u64 *)&frame->uc.uc_sigmask, Efault);
user_access_end();
- if (__copy_siginfo_to_user32(&frame->info, &ksig->info, false))
+ if (__copy_siginfo_to_user32(&frame->info, &ksig->info))
return -EFAULT;
/* Set up registers for signal handler */
diff --git a/arch/x86/include/asm/compat.h b/arch/x86/include/asm/compat.h
index 52e9f34..d4edf28 100644
--- a/arch/x86/include/asm/compat.h
+++ b/arch/x86/include/asm/compat.h
@@ -214,7 +214,11 @@ static inline bool in_compat_syscall(void)
#endif
struct compat_siginfo;
-int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
- const kernel_siginfo_t *from, bool x32_ABI);
+
+#ifdef CONFIG_X86_X32_ABI
+int copy_siginfo_to_user32(struct compat_siginfo __user *to,
+ const kernel_siginfo_t *from);
+#define copy_siginfo_to_user32 copy_siginfo_to_user32
+#endif /* CONFIG_X86_X32_ABI */
#endif /* _ASM_X86_COMPAT_H */
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 83b74fb..f3df262 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -37,6 +37,7 @@
#include <asm/vm86.h>
#ifdef CONFIG_X86_64
+#include <linux/compat.h>
#include <asm/proto.h>
#include <asm/ia32_unistd.h>
#endif /* CONFIG_X86_64 */
@@ -511,6 +512,31 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig,
}
#endif /* CONFIG_X86_32 */
+#ifdef CONFIG_X86_X32_ABI
+static int x32_copy_siginfo_to_user(struct compat_siginfo __user *to,
+ const struct kernel_siginfo *from)
+{
+ struct compat_siginfo new;
+
+ copy_siginfo_to_external32(&new, from);
+ if (from->si_signo == SIGCHLD) {
+ new._sifields._sigchld_x32._utime = from->si_utime;
+ new._sifields._sigchld_x32._stime = from->si_stime;
+ }
+ if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
+ return -EFAULT;
+ return 0;
+}
+
+int copy_siginfo_to_user32(struct compat_siginfo __user *to,
+ const struct kernel_siginfo *from)
+{
+ if (in_x32_syscall())
+ return x32_copy_siginfo_to_user(to, from);
+ return __copy_siginfo_to_user32(to, from);
+}
+#endif /* CONFIG_X86_X32_ABI */
+
static int x32_setup_rt_frame(struct ksignal *ksig,
compat_sigset_t *set,
struct pt_regs *regs)
@@ -543,7 +569,7 @@ static int x32_setup_rt_frame(struct ksignal *ksig,
user_access_end();
if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
- if (__copy_siginfo_to_user32(&frame->info, &ksig->info, true))
+ if (x32_copy_siginfo_to_user(&frame->info, &ksig->info))
return -EFAULT;
}