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>
This commit is contained in:
Christoph Hellwig
2020-05-05 12:12:53 +02:00
committed by Al Viro
parent 5456ffdee6
commit c3b3f52476
5 changed files with 96 additions and 59 deletions

View File

@@ -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 */