linux_dsm_epyc7002/arch/arm/probes/kprobes/Makefile
Wang Nan 0dc016dbd8 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>
2015-01-13 16:10:17 +00:00

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Makefile

obj-$(CONFIG_KPROBES) += core.o actions-common.o checkers-common.o
obj-$(CONFIG_ARM_KPROBES_TEST) += test-kprobes.o
test-kprobes-objs := test-core.o
ifdef CONFIG_THUMB2_KERNEL
obj-$(CONFIG_KPROBES) += actions-thumb.o checkers-thumb.o
test-kprobes-objs += test-thumb.o
else
obj-$(CONFIG_KPROBES) += actions-arm.o checkers-arm.o
obj-$(CONFIG_OPTPROBES) += opt-arm.o
test-kprobes-objs += test-arm.o
endif