Re: [PATCH v3 2/2] arch: wire-up clone3() syscall

[Guenter Roeck <linux@roeck-us.net>]

On Tue, Jun 04, 2019 at 06:09:44PM +0200, Christian Brauner wrote:
> Wire up the clone3() call on all arches that don't require hand-rolled
> assembly.
> 
> Some of the arches look like they need special assembly massaging and it is
> probably smarter if the appropriate arch maintainers would do the actual
> wiring. Arches that are wired-up are:
> - x86{_32,64}
> - arm{64}
> - xtensa
> 

This patch results in build failures on various architecetures.

h8300-linux-ld: arch/h8300/kernel/syscalls.o:(.data+0x6d0): undefined reference to `sys_clone3'

nios2-linux-ld: arch/nios2/kernel/syscall_table.o:(.data+0x6d0): undefined reference to `sys_clone3'

There may be others; -next is in too bad shape right now to get a complete
picture. Wondering, though: What is special with this syscall ? Normally
one would only get a warning that a syscall is not wired up.

Guenter

> 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
> ---
> v1: unchanged
> v2: unchanged
> v3:
> - Christian Brauner <christian@brauner.io>:
>   - wire up clone3 on all arches that don't have hand-rolled entry points
>     for clone
> ---
>  arch/arm/tools/syscall.tbl                  | 1 +
>  arch/arm64/include/asm/unistd.h             | 2 +-
>  arch/arm64/include/asm/unistd32.h           | 2 ++
>  arch/microblaze/kernel/syscalls/syscall.tbl | 1 +
>  arch/x86/entry/syscalls/syscall_32.tbl      | 1 +
>  arch/x86/entry/syscalls/syscall_64.tbl      | 1 +
>  arch/xtensa/kernel/syscalls/syscall.tbl     | 1 +
>  include/uapi/asm-generic/unistd.h           | 4 +++-
>  8 files changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
> index aaf479a9e92d..e99a82bdb93a 100644
> --- a/arch/arm/tools/syscall.tbl
> +++ b/arch/arm/tools/syscall.tbl
> @@ -447,3 +447,4 @@
>  431	common	fsconfig			sys_fsconfig
>  432	common	fsmount				sys_fsmount
>  433	common	fspick				sys_fspick
> +436	common	clone3				sys_clone3
> diff --git a/arch/arm64/include/asm/unistd.h b/arch/arm64/include/asm/unistd.h
> index 70e6882853c0..24480c2d95da 100644
> --- a/arch/arm64/include/asm/unistd.h
> +++ b/arch/arm64/include/asm/unistd.h
> @@ -44,7 +44,7 @@
>  #define __ARM_NR_compat_set_tls		(__ARM_NR_COMPAT_BASE + 5)
>  #define __ARM_NR_COMPAT_END		(__ARM_NR_COMPAT_BASE + 0x800)
>  
> -#define __NR_compat_syscalls		434
> +#define __NR_compat_syscalls		437
>  #endif
>  
>  #define __ARCH_WANT_SYS_CLONE
> diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
> index c39e90600bb3..b144ea675d70 100644
> --- a/arch/arm64/include/asm/unistd32.h
> +++ b/arch/arm64/include/asm/unistd32.h
> @@ -886,6 +886,8 @@ __SYSCALL(__NR_fsconfig, sys_fsconfig)
>  __SYSCALL(__NR_fsmount, sys_fsmount)
>  #define __NR_fspick 433
>  __SYSCALL(__NR_fspick, sys_fspick)
> +#define __NR_clone3 436
> +__SYSCALL(__NR_clone3, sys_clone3)
>  
>  /*
>   * Please add new compat syscalls above this comment and update
> diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl
> index 26339e417695..3110440bcc31 100644
> --- a/arch/microblaze/kernel/syscalls/syscall.tbl
> +++ b/arch/microblaze/kernel/syscalls/syscall.tbl
> @@ -439,3 +439,4 @@
>  431	common	fsconfig			sys_fsconfig
>  432	common	fsmount				sys_fsmount
>  433	common	fspick				sys_fspick
> +436	common	clone3				sys_clone3
> diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
> index ad968b7bac72..80e26211feff 100644
> --- a/arch/x86/entry/syscalls/syscall_32.tbl
> +++ b/arch/x86/entry/syscalls/syscall_32.tbl
> @@ -438,3 +438,4 @@
>  431	i386	fsconfig		sys_fsconfig			__ia32_sys_fsconfig
>  432	i386	fsmount			sys_fsmount			__ia32_sys_fsmount
>  433	i386	fspick			sys_fspick			__ia32_sys_fspick
> +436	i386	clone3			sys_clone3			__ia32_sys_clone3
> diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
> index b4e6f9e6204a..7968f0b5b5e8 100644
> --- a/arch/x86/entry/syscalls/syscall_64.tbl
> +++ b/arch/x86/entry/syscalls/syscall_64.tbl
> @@ -355,6 +355,7 @@
>  431	common	fsconfig		__x64_sys_fsconfig
>  432	common	fsmount			__x64_sys_fsmount
>  433	common	fspick			__x64_sys_fspick
> +436	common	clone3			__x64_sys_clone3/ptregs
>  
>  #
>  # x32-specific system call numbers start at 512 to avoid cache impact
> diff --git a/arch/xtensa/kernel/syscalls/syscall.tbl b/arch/xtensa/kernel/syscalls/syscall.tbl
> index 5fa0ee1c8e00..b2767c8c2b4e 100644
> --- a/arch/xtensa/kernel/syscalls/syscall.tbl
> +++ b/arch/xtensa/kernel/syscalls/syscall.tbl
> @@ -404,3 +404,4 @@
>  431	common	fsconfig			sys_fsconfig
>  432	common	fsmount				sys_fsmount
>  433	common	fspick				sys_fspick
> +436	common	clone3				sys_clone3
> diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
> index a87904daf103..45bc87687c47 100644
> --- a/include/uapi/asm-generic/unistd.h
> +++ b/include/uapi/asm-generic/unistd.h
> @@ -844,9 +844,11 @@ __SYSCALL(__NR_fsconfig, sys_fsconfig)
>  __SYSCALL(__NR_fsmount, sys_fsmount)
>  #define __NR_fspick 433
>  __SYSCALL(__NR_fspick, sys_fspick)
> +#define __NR_clone3 436
> +__SYSCALL(__NR_clone3, sys_clone3)
>  
>  #undef __NR_syscalls
> -#define __NR_syscalls 434
> +#define __NR_syscalls 437
>  
>  /*
>   * 32 bit systems traditionally used different