Re: [PATCH 2/2] MIPS: kernel: signal: Drop unused arguments for traditional signal handlers

[David Daney <ddaney.cavm@gmail.com>]

On 08/20/2015 04:45 AM, Markos Chandras wrote:
> Traditional signal handlers (ie !SA_SIGINFO) only need only argument
> holding the signal number so we drop the additional arguments and fix
> the related comments. We also update the comments for the SA_SIGINFO
> case where the second argument is a pointer to a siginfo_t structure.
>
> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
> ---
>   arch/mips/kernel/signal.c     | 6 +-----
>   arch/mips/kernel/signal32.c   | 6 +-----
>   arch/mips/kernel/signal_n32.c | 2 +-
>   3 files changed, 3 insertions(+), 11 deletions(-)
>
> diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c
> index be3ac5f7cbbb..3a125331bf8b 100644
> --- a/arch/mips/kernel/signal.c
> +++ b/arch/mips/kernel/signal.c
> @@ -683,15 +683,11 @@ static int setup_frame(void *sig_return, struct ksignal *ksig,
>   	 * Arguments to signal handler:
>   	 *
>   	 *   a0 = signal number
> -	 *   a1 = 0 (should be cause)
> -	 *   a2 = pointer to struct sigcontext
>   	 *
>   	 * $25 and c0_epc point to the signal handler, $29 points to the
>   	 * struct sigframe.
>   	 */
>   	regs->regs[ 4] = ksig->sig;
> -	regs->regs[ 5] = 0;
> -	regs->regs[ 6] = (unsigned long) &frame->sf_sc;

This changes the kernel ABI.

Have you tested this change against all userspace applications that use 
signals to make sure it doesn't break anything?

David Daney