[src/trunk]: src/sys/arch/amd64/amd64 fix more bugs in ucas_*():

[chs <chs%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/c4bae5f113be
branches:  trunk
changeset: 756120:c4bae5f113be
user:      chs <chs%NetBSD.org@localhost>
date:      Wed Jul 07 01:13:29 2010 +0000

description:
fix more bugs in ucas_*():
move the "old" value to %*ax so that cmpxchg* can work.
remove the PCB_ONFAULT stuff, onfault_handler() handles this already.
return the error from fault handler in ucas_fault rather than forcing EFAULT.

diffstat:

 sys/arch/amd64/amd64/copy.S |  18 +++++++-----------
 1 files changed, 7 insertions(+), 11 deletions(-)

diffs (62 lines):

diff -r b811b54f9bc2 -r c4bae5f113be sys/arch/amd64/amd64/copy.S
--- a/sys/arch/amd64/amd64/copy.S       Wed Jul 07 01:09:39 2010 +0000
+++ b/sys/arch/amd64/amd64/copy.S       Wed Jul 07 01:13:29 2010 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: copy.S,v 1.17 2010/06/22 18:26:05 rmind Exp $  */
+/*     $NetBSD: copy.S,v 1.18 2010/07/07 01:13:29 chs Exp $    */
 
 /*
  * Copyright (c) 2001 Wasabi Systems, Inc.
@@ -502,13 +502,11 @@
        movq    $VM_MAXUSER_ADDRESS-8, %r8
        cmpq    %r8, %rdi
        ja      _C_LABEL(ucas_fault)
-       /* Label for fault handler */
+       movq    %rsi, %rax
 .Lucas64_start:
        /* Perform the CAS */
        lock
        cmpxchgq %rdx, (%rdi)
-       /* Clear the fault handler */
-       movq    %rax, PCB_ONFAULT(%r8)
 .Lucas64_end:
        /*
         * Note: %rax is "old" value.
@@ -516,8 +514,6 @@
         */
        movq    %rax, (%rcx)
        xorq    %rax, %rax
-       /* Clear the fault handler */
-       movq    %rax, PCB_ONFAULT(%r8)
        ret
        DEFERRED_SWITCH_CALL
 
@@ -530,7 +526,7 @@
        movq    $VM_MAXUSER_ADDRESS-4, %r8
        cmpq    %r8, %rdi
        ja      _C_LABEL(ucas_fault)
-       /* Label for fault handler */
+       movl    %esi, %eax
 .Lucas32_start:
        /* Perform the CAS */
        lock
@@ -546,15 +542,15 @@
        DEFERRED_SWITCH_CALL
 
 /*
- * Fault handler for ucas_32() and ucas_64().
- * Unset the handler and return the failure.
+ * Fault handler for ucas_*().
+ * Just return the error set by trap().
  */
 NENTRY(ucas_fault)
-       movq    $EFAULT, %rax
        ret
 
 /*
- * int ucas_ptr(volatile void *uptr, void *old, void *new, void *ret);
+ * int ucas_ptr(volatile void **uptr, void *old, void *new, void **ret);
+ * int ucas_int(volatile int *uptr, int old, intnew, int *ret);
  */
 STRONG_ALIAS(ucas_ptr, ucas_64)
 STRONG_ALIAS(ucas_int, ucas_32)