From d68dbb0c9ac8b1ff52eb09aa58ce6358400fa939 Mon Sep 17 00:00:00 2001
From: Christian Brauner <christian@brauner.io>
Date: Fri, 21 Jun 2019 01:26:35 +0200
Subject: [PATCH] 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: 8f3220a80654 ("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
---
arch/arm/include/asm/unistd.h | 1 +
arch/arm64/include/asm/unistd.h | 1 +
arch/x86/include/asm/unistd.h | 1 +
arch/xtensa/include/asm/unistd.h | 1 +
kernel/fork.c | 2 ++
kernel/sys_ni.c | 2 ++
6 files changed, 8 insertions(+)
diff --git a/arch/arm/include/asm/unistd.h b/arch/arm/include/asm/unistd.h
index 7a39e77984eff..aa35aa5d68dc4 100644
--- a/arch/arm/include/asm/unistd.h
+++ b/arch/arm/include/asm/unistd.h
@@ -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
diff --git a/arch/arm64/include/asm/unistd.h b/arch/arm64/include/asm/unistd.h
index 24480c2d95da4..e4e0523102e24 100644
--- a/arch/arm64/include/asm/unistd.h
+++ b/arch/arm64/include/asm/unistd.h
@@ -48,6 +48,7 @@
#endif
#define __ARCH_WANT_SYS_CLONE
+#define __ARCH_WANT_SYS_CLONE3
#ifndef __COMPAT_SYSCALL_NR
#include <uapi/asm/unistd.h>
diff --git a/arch/x86/include/asm/unistd.h b/arch/x86/include/asm/unistd.h
index 146859efd83c6..097589753fece 100644
--- a/arch/x86/include/asm/unistd.h
+++ b/arch/x86/include/asm/unistd.h
@@ -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 */
diff --git a/arch/xtensa/include/asm/unistd.h b/arch/xtensa/include/asm/unistd.h
index 30af4dc3ce7b8..b52236245e515 100644
--- a/arch/xtensa/include/asm/unistd.h
+++ b/arch/xtensa/include/asm/unistd.h
@@ -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
diff --git a/kernel/fork.c b/kernel/fork.c
index 08ff131f26b4a..98abea9956299 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -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)
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index 4d9ae5ea6caff..34b76895b81e8 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -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);
--
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