Re: [PATCH] Add FUTEX_CMP_REQUEUE futex op

From: Pete Zaitcev
Date: Wed Jun 09 2004 - 15:07:33 EST


On Mon, 7 Jun 2004 18:03:49 +0200
Martin Schwidefsky <schwidefsky@xxxxxxxxxx> wrote:

> --- linux-2.6/arch/s390/kernel/compat_wrapper.S Mon Jun 7 16:07:24 2004
> +++ linux-2.6-s390/arch/s390/kernel/compat_wrapper.S Mon Jun 7 16:07:53 2004
> @@ -1097,6 +1097,8 @@
> lgfr %r4,%r4 # int
> llgtr %r5,%r5 # struct compat_timespec *
> llgtr %r6,%r6 # u32 *
> + lgf %r0,164(%r15) # int
> + stg %r0,160(%r15)
> jg compat_sys_futex # branch to system call
>
> .globl sys32_setxattr_wrapper

Is it just me, or this could he above stand a use of STACK_FRAME_OVERHEAD
instead of 160? I envision a time when Ulrich Weigand comes out with
a gcc -fkernel, and at that time we'll need all such references
configurable.

> diff -urN linux-2.6/include/asm-s390/ptrace.h linux-2.6-s390/include/asm-s390/ptrace.h
> --- linux-2.6/include/asm-s390/ptrace.h Mon May 10 04:32:54 2004
> +++ linux-2.6-s390/include/asm-s390/ptrace.h Mon Jun 7 16:07:53 2004
> @@ -303,6 +303,7 @@
> */
> struct pt_regs
> {
> + unsigned long args[1];
> psw_t psw;

This worries me, together with
(__u32*)((addr_t) &__KSTK_PTREGS(child)->psw

Why not to place the necessary word outside of the struct?
It just logically doesn't belong. Might be just as easy to
do that mvc to other place.

I think I'll try to scope such an implemenation.

-- Pete
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