This patch restores the changes of commit dff38e3e93 "x86: Use inline assembler instead of global register variable to get sp". They got lost in commit 198d208df4 "x86: Keep thread_info on thread stack in x86_32" while moving the code to arch/x86/kernel/irq_32.c.
Quoting Andi from commit dff38e3e93: """ LTO in gcc 4.6/47. has trouble with global register variables. They were used to read the stack pointer. Use a simple inline assembler statement with a mov instead. This also helps LLVM/clang, which does not support global register variables. """ Cc: Steven Rostedt <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Andi Kleen <[email protected]> Cc: H. Peter Anvin <[email protected]> Signed-off-by: Mathias Krause <[email protected]> --- If it's not obvious, this patch should be applied to tip.git on top of tip/x86/threadinfo. arch/x86/kernel/irq_32.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c index 988dc8bcae..63ce838e5a 100644 --- a/arch/x86/kernel/irq_32.c +++ b/arch/x86/kernel/irq_32.c @@ -70,7 +70,11 @@ static void call_on_stack(void *func, void *stack) } /* how to get the current stack pointer from C */ -register unsigned long current_stack_pointer asm("esp") __used; +#define current_stack_pointer ({ \ + unsigned long sp; \ + asm("mov %%esp,%0" : "=g" (sp)); \ + sp; \ +}) static inline void *current_stack(void) { -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
