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Fix InterlockedExchange for non-armv6+ ARMV processors. Original InterlockedExchange was not atomic in regards to the other Interlocked* functions, leading to crashes if they were used.

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Instead of directly using "swp" in InterlockedExchange, use
 - kuser_cmpxchg if available (on Linux/armel)
 - the fpc global mutex (fpc_system_lock) otherwise
to implement it.

git-svn-id: trunk@22062 -
This commit is contained in:
tom_at_work 2012-08-11 19:32:11 +00:00
parent 19debd87cc
commit 9a82fb9eb4
1 changed files with 44 additions and 6 deletions
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50
rtl/arm/arm.inc
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@ -555,7 +555,6 @@ asm
bx lr
{$else}
{$if defined(LINUX) and defined(CPUARMEL)}
stmfd r13!, {lr}
mov r2, r0 // kuser_cmpxchg does not clobber r2 by definition
.Latomic_dec_loop:
@ -640,7 +639,6 @@ asm
bx lr
{$else}
{$if defined(LINUX) and defined(CPUARMEL)}
stmfd r13!, {lr}
mov r2, r0 // kuser_cmpxchg does not clobber r2 by definition
.Latomic_inc_loop:
@ -700,8 +698,50 @@ asm
mov r0, r2
bx lr
{$else}
swp r1, r1, [r0]
mov r0,r1
{$if defined(LINUX) and defined(CPUARMEL)}
stmfd r13!, {r4, lr}
mov r2, r0 // kuser_cmpxchg does not clobber r2 (and r1) by definition
.Latomic_add_loop:
ldr r0, [r2] // Load the current value
mov r4, r0 // save the current value because kuser_cmpxchg clobbers r0
// We expect this to work without looping most of the time
// R3 gets clobbered in kuser_cmpxchg so in the unlikely case that we have to
// loop here again, we have to reload the value. Normaly this just fills the
// load stall-cycles from the above ldr so in reality we'll not get any additional
// delays because of this
// Don't use ldr to load r3 to avoid cacheline trashing
// Load 0xffff0fff into r3 and substract to 0xffff0fc0,
// the kuser_cmpxchg entry point
mvn r3, #0x0000f000
sub r3, r3, #0x3F
blx r3 // Call kuser_cmpxchg, sets C-Flag on success
// restore the original value if needed
movcs r0, r4
ldmcsfd r13!, {r4, pc}
b .Latomic_add_loop // kuser_cmpxchg failed, loop back
{$else}
// lock
ldr r3, .Lfpc_system_lock
mov r2, #1
.Lloop:
swp r2, r2, [r3]
cmp r2, #0
bne .Lloop
// do the job
ldr r2, [r0]
str r1, [r0]
mov r0, r2
// unlock and return
mov r2, #0
str r2, [r3]
bx lr
.Lfpc_system_lock:
.long fpc_system_lock
{$endif}
{$endif}
end;
@ -718,7 +758,6 @@ asm
bx lr
{$else}
{$if defined(LINUX) and defined(CPUARMEL)}
stmfd r13!, {r4, lr}
mov r2, r0 // kuser_cmpxchg does not clobber r2 by definition
mov r4, r1 // Save addend
@ -785,7 +824,6 @@ asm
bx lr
{$else}
{$if defined(LINUX) and defined(CPUARMEL)}
stmfd r13!, {r4, lr}
mvn r3, #0x0000f000
sub r3, r3, #0x3F