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| author | Wang Nan <wangnan0@huawei.com> | 2015-01-09 07:37:36 +0100 |
|---|---|---|
| committer | Jon Medhurst <tixy@linaro.org> | 2015-01-13 17:10:17 +0100 |
| commit | 0dc016dbd820260b8ea74337980735b8c88d4ef2 (patch) | |
| tree | 0a6408b4181016d41858afec026cc4e93455f852 /arch/arm/kernel/ftrace.c | |
| parent | kprobes: Pass the original kprobe for preparing optimized kprobe (diff) | |
| download | linux-0dc016dbd820260b8ea74337980735b8c88d4ef2.tar.xz linux-0dc016dbd820260b8ea74337980735b8c88d4ef2.zip | |
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.c | 3 |
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} */ |