arch: handle arches who do not yet define clone3

This cleanly handles arches who do not yet define clone3.

clone3() was initially placed under __ARCH_WANT_SYS_CLONE under the
assumption that this would cleanly handle all architectures. It does
not.
Architectures such as nios2 or h8300 simply take the asm-generic syscall
definitions and generate their syscall table from it. Since they don't
define __ARCH_WANT_SYS_CLONE the build would fail complaining about
sys_clone3 missing. The reason this doesn't happen for legacy clone is
that nios2 and h8300 provide assembly stubs for sys_clone. This seems to
be done for architectural reasons.

The build failures for nios2 and h8300 were caught int -next luckily.
The solution is to define __ARCH_WANT_SYS_CLONE3 that architectures can
add. Additionally, we need a cond_syscall(clone3) for architectures such
as nios2 or h8300 that generate their syscall table in the way I
explained above.

Fixes: 8f3220a806 ("arch: wire-up clone3() syscall")
Signed-off-by: Christian Brauner <christian@brauner.io>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Adrian Reber <adrian@lisas.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: linux-api@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: x86@kernel.org
This commit is contained in:
Christian Brauner 2019-06-21 01:26:35 +02:00
parent 8f3220a806
commit d68dbb0c9a
No known key found for this signature in database
GPG Key ID: 8EB056D53EECB12D
6 changed files with 8 additions and 0 deletions

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@ -40,6 +40,7 @@
#define __ARCH_WANT_SYS_FORK
#define __ARCH_WANT_SYS_VFORK
#define __ARCH_WANT_SYS_CLONE
#define __ARCH_WANT_SYS_CLONE3
/*
* Unimplemented (or alternatively implemented) syscalls

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@ -48,6 +48,7 @@
#endif
#define __ARCH_WANT_SYS_CLONE
#define __ARCH_WANT_SYS_CLONE3
#ifndef __COMPAT_SYSCALL_NR
#include <uapi/asm/unistd.h>

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@ -54,5 +54,6 @@
# define __ARCH_WANT_SYS_FORK
# define __ARCH_WANT_SYS_VFORK
# define __ARCH_WANT_SYS_CLONE
# define __ARCH_WANT_SYS_CLONE3
#endif /* _ASM_X86_UNISTD_H */

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@ -3,6 +3,7 @@
#define _XTENSA_UNISTD_H
#define __ARCH_WANT_SYS_CLONE
#define __ARCH_WANT_SYS_CLONE3
#include <uapi/asm/unistd.h>
#define __ARCH_WANT_NEW_STAT

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@ -2490,7 +2490,9 @@ SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp,
return _do_fork(&args);
}
#endif
#ifdef __ARCH_WANT_SYS_CLONE3
noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs,
struct clone_args __user *uargs,
size_t size)

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@ -137,6 +137,8 @@ COND_SYSCALL(capset);
/* kernel/exit.c */
/* kernel/fork.c */
/* __ARCH_WANT_SYS_CLONE3 */
COND_SYSCALL(clone3);
/* kernel/futex.c */
COND_SYSCALL(futex);