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Convert _lock_cas to RAS. Check for restart in ast() on return from interrupt.

This commit is contained in:
uwe 2007-03-14 05:03:52 +00:00
parent 8a56ee5512
commit 07a908343d
2 changed files with 21 additions and 15 deletions
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14
sys/arch/sh3/sh3/exception.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: exception.c,v 1.35 2007/02/21 22:59:51 thorpej Exp $ */
/* $NetBSD: exception.c,v 1.36 2007/03/14 05:03:52 uwe Exp $ */
/*-
* Copyright (c) 2002 The NetBSD Foundation, Inc. All rights reserved.
@ -79,7 +79,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: exception.c,v 1.35 2007/02/21 22:59:51 thorpej Exp $");
__KERNEL_RCSID(0, "$NetBSD: exception.c,v 1.36 2007/03/14 05:03:52 uwe Exp $");
#include "opt_ddb.h"
#include "opt_kgdb.h"
@ -436,8 +436,16 @@ void
ast(struct lwp *l, struct trapframe *tf)
{
if (KERNELMODE(tf->tf_ssr))
if (KERNELMODE(tf->tf_ssr)) {
extern char _lock_cas_ras_start[];
extern char _lock_cas_ras_end[];
if ((uintptr_t)tf->tf_spc > (uintptr_t)_lock_cas_ras_start
&& (uintptr_t)tf->tf_spc < (uintptr_t)_lock_cas_ras_end)
tf->tf_spc = (uintptr_t)_lock_cas_ras_start;
return;
}
KDASSERT(l != NULL);
KDASSERT(l->l_md.md_regs == tf);

22
sys/arch/sh3/sh3/lock_stubs.S
View File

@ -1,4 +1,4 @@
/* $NetBSD: lock_stubs.S,v 1.5 2007/03/14 02:01:19 uwe Exp $ */
/* $NetBSD: lock_stubs.S,v 1.6 2007/03/14 05:03:52 uwe Exp $ */
/*
* Copyright (c) 2007 Valeriy E. Ushakov
@ -42,25 +42,23 @@
/*
* LINTSTUB: Func: int _lock_cas(volatile uintptr_t *ptr, uintptr_t old, uintptr_t new);
*
* Brute force with splhigh() for now. Need to be redone as RAS.
* Atomic compare-and-swap for kernel use. SuperH machines are
* uniprocessor, so we need to be atomic only w.r.t. interrupts.
* Implement this as (the only in-kernel) RAS, with restart check
* done in ast() on return from interrupt.
*/
NENTRY(_lock_cas)
mov #PSL_IMASK, r2 ! 0xf0 - gets sign extended
stc sr, r3
extu.b r2, r2 ! undo sign extention
mov r3, r7 ! preserve SR
or r2, r3 ! mask all interrupts
ldc r3, sr
ALTENTRY(_lock_cas_ras_start)
mov.l @r4, r1
cmp/eq r1, r5 ! T = (*ptr == old)
bf.s 1f
movt r0 ! retval = T
mov.l r6, @r4 ! *ptr = new
1:
ldc r7, sr ! restore SR (cannot be in delay slot)
rts
ALTENTRY(_lock_cas_ras_end)
1: rts
nop
SET_ENTRY_SIZE(_lock_cas)
#if !defined(LOCKDEBUG)