diff options
author | Rabin Vincent <rabin@rab.in> | 2012-02-18 16:52:41 (GMT) |
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committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2012-03-24 09:38:56 (GMT) |
commit | 09f05d8529ff4aa92311c1a55ce35ac98cb59b8c (patch) | |
tree | 0196ddc9e80d74c8d3e3473bd7bc21b3e520c3d9 /arch/arm/include | |
parent | a9468f30b5eac6957c86aea97954553bfb7c1f18 (diff) | |
download | linux-fsl-qoriq-09f05d8529ff4aa92311c1a55ce35ac98cb59b8c.tar.xz |
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 <jbaron@redhat.com>
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/include')
-rw-r--r-- | arch/arm/include/asm/jump_label.h | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/arch/arm/include/asm/jump_label.h b/arch/arm/include/asm/jump_label.h new file mode 100644 index 0000000..5c5ca2e --- /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 <linux/types.h> +#include <asm/system.h> + +#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 |