[PATCH] ARM: 2664/2: add support for atomic ops on pre-ARMv6 SMP systems

Patch from Nicolas Pitre

Not that there might be many of them on the planet, but at least RMK
apparently has one.

Signed-off-by: Nicolas Pitre
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Nicolas Pitre
2005-06-08 19:00:47 +01:00
committed by Russell King
parent aeabbbbe12
commit dcef1f6346
3 changed files with 68 additions and 5 deletions
+11 -5
View File
@@ -269,7 +269,7 @@ __pabt_svc:
add r5, sp, #S_PC
ldmia r7, {r2 - r4} @ Get USR pc, cpsr
#if __LINUX_ARM_ARCH__ < 6
#if __LINUX_ARM_ARCH__ < 6 && !defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG)
@ make sure our user space atomic helper is aborted
cmp r2, #VIRT_OFFSET
bichs r3, r3, #PSR_Z_BIT
@@ -616,11 +616,17 @@ __kuser_helper_start:
__kuser_cmpxchg: @ 0xffff0fc0
#if __LINUX_ARM_ARCH__ < 6
#if defined(CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG)
#ifdef CONFIG_SMP /* sanity check */
#error "CONFIG_SMP on a machine supporting pre-ARMv6 processors?"
#endif
/*
* Poor you. No fast solution possible...
* The kernel itself must perform the operation.
* A special ghost syscall is used for that (see traps.c).
*/
swi #0x9ffff0
mov pc, lr
#elif __LINUX_ARM_ARCH__ < 6
/*
* Theory of operation: