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| author | Nicolas Pitre <nico@org.rmk.(none)> | 2005-06-08 19:00:47 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2005-06-08 19:00:47 +0100 |
| commit | dcef1f634657dabe7905af3ccda12cf7f0b6fcc1 (patch) | |
| tree | e1b8bf471c3c268d0be919561268c24f298d031b /arch/arm/kernel/entry-armv.S | |
| parent | aeabbbbe126f3d5e61e2db07629443cd10932bb2 (diff) | |
| download | op-kernel-dev-dcef1f634657dabe7905af3ccda12cf7f0b6fcc1.zip op-kernel-dev-dcef1f634657dabe7905af3ccda12cf7f0b6fcc1.tar.gz | |
[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>
Diffstat (limited to 'arch/arm/kernel/entry-armv.S')
| -rw-r--r-- | arch/arm/kernel/entry-armv.S | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S index 4eb3615..e14278d 100644 --- a/arch/arm/kernel/entry-armv.S +++ b/arch/arm/kernel/entry-armv.S @@ -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: |
