Commit 09f05d85 authored by Rabin Vincent's avatar Rabin Vincent Committed by Russell King

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: default avatarRabin Vincent <rabin@rab.in>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent a9468f30
......@@ -9,6 +9,7 @@ config ARM
select SYS_SUPPORTS_APM_EMULATION
select GENERIC_ATOMIC64 if (CPU_V6 || !CPU_32v6K || !AEABI)
select HAVE_OPROFILE if (HAVE_PERF_EVENTS)
select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL
select HAVE_ARCH_KGDB
select HAVE_KPROBES if !XIP_KERNEL
select HAVE_KRETPROBES if (HAVE_KPROBES)
......
#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
......@@ -38,6 +38,7 @@ obj-$(CONFIG_HAVE_ARM_SCU) += smp_scu.o
obj-$(CONFIG_HAVE_ARM_TWD) += smp_twd.o
obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o insn.o
obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o insn.o
obj-$(CONFIG_JUMP_LABEL) += jump_label.o insn.o patch.o
obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o
obj-$(CONFIG_KPROBES) += kprobes.o kprobes-common.o patch.o
ifdef CONFIG_THUMB2_KERNEL
......
#ifndef __ASM_ARM_INSN_H
#define __ASM_ARM_INSN_H
static inline unsigned long
arm_gen_nop(void)
{
#ifdef CONFIG_THUMB2_KERNEL
return 0xf3af8000; /* nop.w */
#else
return 0xe1a00000; /* mov r0, r0 */
#endif
}
unsigned long
__arm_gen_branch(unsigned long pc, unsigned long addr, bool link);
......
#include <linux/kernel.h>
#include <linux/jump_label.h>
#include "insn.h"
#include "patch.h"
#ifdef HAVE_JUMP_LABEL
static void __arch_jump_label_transform(struct jump_entry *entry,
enum jump_label_type type,
bool is_static)
{
void *addr = (void *)entry->code;
unsigned int insn;
if (type == JUMP_LABEL_ENABLE)
insn = arm_gen_branch(entry->code, entry->target);
else
insn = arm_gen_nop();
if (is_static)
__patch_text(addr, insn);
else
patch_text(addr, insn);
}
void arch_jump_label_transform(struct jump_entry *entry,
enum jump_label_type type)
{
__arch_jump_label_transform(entry, type, false);
}
void arch_jump_label_transform_static(struct jump_entry *entry,
enum jump_label_type type)
{
__arch_jump_label_transform(entry, type, true);
}
#endif
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment