From 09f05d8529ff4aa92311c1a55ce35ac98cb59b8c Mon Sep 17 00:00:00 2001 From: Rabin Vincent Date: Sat, 18 Feb 2012 17:52:41 +0100 Subject: ARM: 7334/1: add jump label support Add the arch-specific code to support jump labels for ARM and Thumb-2. This code will only be activated on compilers that are capable of building it. It has been tested with GCC 4.6 patched with the patch from GCC bug 48637. Cc: Jason Baron Signed-off-by: Rabin Vincent Signed-off-by: Russell King --- arch/arm/include/asm/jump_label.h | 41 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 arch/arm/include/asm/jump_label.h (limited to 'arch/arm/include/asm') diff --git a/arch/arm/include/asm/jump_label.h b/arch/arm/include/asm/jump_label.h new file mode 100644 index 00000000000..5c5ca2ea62b --- /dev/null +++ b/arch/arm/include/asm/jump_label.h @@ -0,0 +1,41 @@ +#ifndef _ASM_ARM_JUMP_LABEL_H +#define _ASM_ARM_JUMP_LABEL_H + +#ifdef __KERNEL__ + +#include +#include + +#define JUMP_LABEL_NOP_SIZE 4 + +#ifdef CONFIG_THUMB2_KERNEL +#define JUMP_LABEL_NOP "nop.w" +#else +#define JUMP_LABEL_NOP "nop" +#endif + +static __always_inline bool arch_static_branch(struct jump_label_key *key) +{ + asm goto("1:\n\t" + JUMP_LABEL_NOP "\n\t" + ".pushsection __jump_table, \"aw\"\n\t" + ".word 1b, %l[l_yes], %c0\n\t" + ".popsection\n\t" + : : "i" (key) : : l_yes); + + return false; +l_yes: + return true; +} + +#endif /* __KERNEL__ */ + +typedef u32 jump_label_t; + +struct jump_entry { + jump_label_t code; + jump_label_t target; + jump_label_t key; +}; + +#endif -- cgit v1.2.3