From ef2b343e99e772e35f0f9d00f7db318b6629c16e Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Fri, 10 Nov 2006 21:32:40 +0000 Subject: [POWERPC] Make soft_enabled irqs preempt safe Rewrite local_get_flags and local_irq_disable to use r13 explicitly, to avoid the risk that gcc will split get_paca()->soft_enabled into a sequence unsafe against preemption. Similar care in local_irq_restore. Signed-off-by: Hugh Dickins Signed-off-by: Paul Mackerras --- include/asm-powerpc/hw_irq.h | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) (limited to 'include/asm-powerpc') diff --git a/include/asm-powerpc/hw_irq.h b/include/asm-powerpc/hw_irq.h index c4a1ab608f6..fd3f2a20627 100644 --- a/include/asm-powerpc/hw_irq.h +++ b/include/asm-powerpc/hw_irq.h @@ -18,15 +18,25 @@ extern void timer_interrupt(struct pt_regs *); static inline unsigned long local_get_flags(void) { - return get_paca()->soft_enabled; + unsigned long flags; + + __asm__ __volatile__("lbz %0,%1(13)" + : "=r" (flags) + : "i" (offsetof(struct paca_struct, soft_enabled))); + + return flags; } static inline unsigned long local_irq_disable(void) { - unsigned long flag = get_paca()->soft_enabled; - get_paca()->soft_enabled = 0; - barrier(); - return flag; + unsigned long flags, zero; + + __asm__ __volatile__("li %1,0; lbz %0,%2(13); stb %1,%2(13)" + : "=r" (flags), "=&r" (zero) + : "i" (offsetof(struct paca_struct, soft_enabled)) + : "memory"); + + return flags; } extern void local_irq_restore(unsigned long); -- cgit v1.2.3