Re: CONFIG_GENERIC_SIGALTSTACK with asm-generic/syscalls.h (was Re: [git pull] signal.git pile 2)

[James Hogan <james.hogan@imgtec.com>]

On 21/12/12 06:24, Vineet Gupta wrote:
> On Friday 21 December 2012 05:51 AM, Al Viro wrote:
>> sigaltstack infrastructure + conversion for x86, alpha and um,
>> COMPAT_SYSCALL_DEFINE infrastructure.  Note that there are several
>> conflicts between "unify SS_ONSTACK/SS_DISABLE definitions" and
>> UAPI patches in mainline; resolution is trivial - just remove definitions
>> of SS_ONSTACK and SS_DISABLED from arch/*/uapi/asm/signal.h; they are
>> all identical and include/uapi/linux/signal.h contains the unified
>> variant.  Please, pull from
>> git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal for-linus
>>
> 
> Hi Arnd,
> 
> In Linus' tree with above merged, selecting CONFIG_GENERIC_SIGALTSTACK
> is causing build issues for ARC port (and possibly others as well) which
> use asm-generic/syscalls.h due to a different prototype for
> sys_sigaltstack coming in from linux/syscalls.h
> 
> While I can band-aid ARC port by #define sys_sigaltstack before
> including asm-generic, it might be better if we conditional-ize one of
> the prototypes. Following works for me.
> 
> diff --git a/include/asm-generic/syscalls.h b/include/asm-generic/syscalls.h
> index 58f466f..1db51b8 100644
> --- a/include/asm-generic/syscalls.h
> +++ b/include/asm-generic/syscalls.h
> @@ -21,10 +21,12 @@ asmlinkage long sys_mmap(unsigned long addr, unsigned long len,
>                         unsigned long fd, off_t pgoff);
>  #endif
> 
> +#ifndef CONFIG_GENERIC_SIGALTSTACK
>  #ifndef sys_sigaltstack
>  asmlinkage long sys_sigaltstack(const stack_t __user *, stack_t __user *,
>                         struct pt_regs *);
>  #endif
> +#endif

Reviewed-by: James Hogan <james.hogan@imgtec.com>

I also see this issue with metag when I try and select
CONFIG_GENERIC_SIGALTSTACK. Until asm-generic/syscalls.h goes away it
seems a shame to have to keep a misleading #define sys_sigaltstack
sys_sigaltstack bodge in architecture's asm/syscalls.h.

Cheers
James