Messages in this thread Patch in this message | | | From | Christophe Leroy <> | Subject | [PATCH 1/2] powerpc/irq: don't use current_stack_pointer() in check_stack_overflow() | Date | Mon, 9 Dec 2019 06:07:21 +0000 (UTC) |
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current_stack_pointer() doesn't return the stack pointer, but the caller's stack frame. See commit bfe9a2cfe91a ("powerpc: Reimplement __get_SP() as a function not a define") and commit acf620ecf56c ("powerpc: Rename __get_SP() to current_stack_pointer()") for details.
The purpose of check_stack_overflow() is to verify that the stack has not overflowed.
To really know whether the stack pointer is still within boundaries, the check must be done directly on the value of r1.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> --- arch/powerpc/kernel/irq.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c index bb34005ff9d2..4d468d835558 100644 --- a/arch/powerpc/kernel/irq.c +++ b/arch/powerpc/kernel/irq.c @@ -599,9 +599,8 @@ u64 arch_irq_stat_cpu(unsigned int cpu) static inline void check_stack_overflow(void) { #ifdef CONFIG_DEBUG_STACKOVERFLOW - long sp; - - sp = current_stack_pointer() & (THREAD_SIZE-1); + register unsigned long r1 asm("r1"); + long sp = r1 & (THREAD_SIZE - 1); /* check for stack overflow: is there less than 2KB free? */ if (unlikely(sp < 2048)) { -- 2.13.3
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