diff options
| author | Mathias Krause <[email protected]> | 2014-03-07 08:52:32 +0100 |
|---|---|---|
| committer | H. Peter Anvin <[email protected]> | 2014-03-10 17:32:01 -0700 |
| commit | 6cce16f99d7be23cec7cabdf32a8166eec6e5393 (patch) | |
| tree | e73a1d334a61d856905c3656b6a42fc8332760c0 | |
| parent | 2223f6f6eeaad6ea0a3acd3f4bc1ae45e8117ddc (diff) | |
x86, threadinfo: Redo "x86: Use inline assembler to get sp"
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]>
Signed-off-by: Mathias Krause <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: H. Peter Anvin <[email protected]>
| -rw-r--r-- | arch/x86/kernel/irq_32.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c index 988dc8bcaebf..63ce838e5a54 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) { |