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authorWang Nan <wangnan0@huawei.com>2015-01-09 14:37:36 +0800
committerJon Medhurst <tixy@linaro.org>2015-01-13 16:10:17 +0000
commit0dc016dbd820260b8ea74337980735b8c88d4ef2 (patch)
tree0a6408b4181016d41858afec026cc4e93455f852 /arch/arm/kernel/ftrace.c
parentcbf6ab52add20b845f903decc973afbd5463c527 (diff)
ARM: kprobes: enable OPTPROBES for ARM 32
This patch introduce kprobeopt for ARM 32. Limitations: - Currently only kernel compiled with ARM ISA is supported. - Offset between probe point and optinsn slot must not larger than 32MiB. Masami Hiramatsu suggests replacing 2 words, it will make things complex. Futher patch can make such optimization. Kprobe opt on ARM is relatively simpler than kprobe opt on x86 because ARM instruction is always 4 bytes aligned and 4 bytes long. This patch replace probed instruction by a 'b', branch to trampoline code and then calls optimized_callback(). optimized_callback() calls opt_pre_handler() to execute kprobe handler. It also emulate/simulate replaced instruction. When unregistering kprobe, the deferred manner of unoptimizer may leave branch instruction before optimizer is called. Different from x86_64, which only copy the probed insn after optprobe_template_end and reexecute them, this patch call singlestep to emulate/simulate the insn directly. Futher patch can optimize this behavior. Signed-off-by: Wang Nan <wangnan0@huawei.com> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Will Deacon <will.deacon@arm.com> Reviewed-by: Jon Medhurst (Tixy) <tixy@linaro.org> Signed-off-by: Jon Medhurst <tixy@linaro.org>
Diffstat (limited to 'arch/arm/kernel/ftrace.c')
-rw-r--r--arch/arm/kernel/ftrace.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
index b8c75e45a950..709ee1d6d4df 100644
--- a/arch/arm/kernel/ftrace.c
+++ b/arch/arm/kernel/ftrace.c
@@ -20,8 +20,7 @@
#include <asm/cacheflush.h>
#include <asm/opcodes.h>
#include <asm/ftrace.h>
-
-#include "insn.h"
+#include <asm/insn.h>
#ifdef CONFIG_THUMB2_KERNEL
#define NOP 0xf85deb04 /* pop.w {lr} */