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[NTOSKRNL]

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Patch by Paolo Bonzini <bonzini [at] gnu [dot] org>
Fix implementation of ExInterlockedAddLargeStatistic
The old version wasn't really atomic.

See issue #6223 for more details.

svn path=/trunk/; revision=51748
This commit is contained in:
Timo Kreuzer 2011-05-14 19:29:42 +00:00
parent c016e5d41e
commit e12ea18992
1 changed files with 46 additions and 15 deletions
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61
reactos/ntoskrnl/ex/i386/fastinterlck_asm.S
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@ -4,8 +4,9 @@
* FILE: ntoskrnl/ex/i386/fastinterlck_asm.S
* PURPOSE: FASTCALL Interlocked Functions
* PROGRAMMERS: Alex Ionescu (alex@relsoft.net)
* Paolo Bonzini <bonzini [at] gnu [dot] org>
*/
/* INCLUDES ******************************************************************/
#include <asm.inc>
@ -31,26 +32,56 @@
*/
PUBLIC @ExInterlockedAddLargeStatistic@8
@ExInterlockedAddLargeStatistic@8:
push ebp
push ebx
mov ebp, ecx
#ifdef CONFIG_SMP
/* Do the addition */
lock add [ecx], edx
Again:
/* Load comparand in eax for cmpxchg */
mov eax, [ebp]
/* Check for carry bit and return */
jb .l1
/* Compute low word of the result in ebx */
mov ebx, edx
add ebx, eax
/* Carry needs cmpxchg8b */
jc Slow
/* Fast path still needs to be atomic, so use cmpxchg and retry if it fails
* Hopefully it will still get through this path :) */
LOCK cmpxchg [ecx], ebx
jnz Again
/* Thats it */
pop ebx
pop ebp
ret
.l1:
/* Add carry */
lock adc dword ptr [ecx+4], 0
#else
/* Do the addition and add the carry */
add dword ptr [ecx], edx
adc dword ptr [ecx+4], 0
#endif
/* Return */
Slow:
/* Save increment across cmpxchg8b */
push edx
/* Finish loading comparand in edx:eax */
mov edx, [ebp+4]
/* Result in ecx:ebx (we know there's carry) */
lea ecx, [edx+1]
/* Do a full exchange */
LOCK cmpxchg8b [ebp]
/* restore increment */
pop edx
/* Need to retry */
jnz Again
/* Thats it */
pop ebx
pop ebp
ret
/*ULONG
*FASTCALL
*ExfInterlockedAddUlong(IN PULONG Addend,