linux/arch/x86/include/asm/jump_label.h
Jason Baron ef64789413 jump label: Add _ASM_ALIGN for x86 and x86_64
The linker should not be adding holes to word size aligned pointers, but
out of paranoia we are explicitly specifying that alignment. I have not
seen any holes in the jump label section in practice.

Signed-off-by: Jason Baron <jbaron@redhat.com>
LKML-Reference: <e119fbd060c9452c56063ea6148ba1070e7434cc.1300299760.git.jbaron@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-04 13:42:51 -04:00

43 lines
753 B
C

#ifndef _ASM_X86_JUMP_LABEL_H
#define _ASM_X86_JUMP_LABEL_H
#ifdef __KERNEL__
#include <linux/types.h>
#include <asm/nops.h>
#include <asm/asm.h>
#define JUMP_LABEL_NOP_SIZE 5
#define JUMP_LABEL_INITIAL_NOP ".byte 0xe9 \n\t .long 0\n\t"
static __always_inline bool arch_static_branch(struct jump_label_key *key)
{
asm goto("1:"
JUMP_LABEL_INITIAL_NOP
".pushsection __jump_table, \"aw\" \n\t"
_ASM_ALIGN "\n\t"
_ASM_PTR "1b, %l[l_yes], %c0 \n\t"
".popsection \n\t"
: : "i" (key) : : l_yes);
return false;
l_yes:
return true;
}
#endif /* __KERNEL__ */
#ifdef CONFIG_X86_64
typedef u64 jump_label_t;
#else
typedef u32 jump_label_t;
#endif
struct jump_entry {
jump_label_t code;
jump_label_t target;
jump_label_t key;
};
#endif