Re: [PATCH 1/2] alpha: Remove "strange" OSF/1 fork semantics

[Måns Rullgård]

Richard Henderson <rth@xxxxxxxxxxx> writes:

> The assignment to regs->r20 kills the original tls_val input
> to the clone syscall, which means that clone can no longer be
> restarted with the original inputs.
>
> We could, perhaps, retain this result for true fork, but OSF/1
> compatibility is no longer important.  Note that glibc has never
> used the r20 result value, instead always testing r0 vs 0 to
> determine the child/parent status.

What effect does this have on OSF/1 compat?

> This failure can be seen in the glibc nptl/tst-eintr* tests.
>
> Reported-by: Michael Cree <mcree@xxxxxxxxxxxx>
> Signed-off-by: Richard Henderson <rth@xxxxxxxxxxx>
> ---
>  arch/alpha/kernel/process.c | 2 --
>  1 file changed, 2 deletions(-)
>
> diff --git a/arch/alpha/kernel/process.c b/arch/alpha/kernel/process.c
> index 1941a07..77028d7 100644
> --- a/arch/alpha/kernel/process.c
> +++ b/arch/alpha/kernel/process.c
> @@ -278,8 +278,6 @@ copy_thread(unsigned long clone_flags, unsigned long usp,
>  	*childregs = *regs;
>  	childregs->r0 = 0;
>  	childregs->r19 = 0;
> -	childregs->r20 = 1;	/* OSF/1 has some strange fork() semantics.  */
> -	regs->r20 = 0;
>  	stack = ((struct switch_stack *) regs) - 1;
>  	*childstack = *stack;
>  	childstack->r26 = (unsigned long) ret_from_fork;
> -- 
> 1.9.3
>

-- 
Måns Rullgård
mans@xxxxxxxxx
--
To unsubscribe from this list: send the line "unsubscribe linux-alpha" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html