mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-01 07:56:44 +07:00
0dc016dbd8
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>
30 lines
563 B
C
30 lines
563 B
C
#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);
|
|
|
|
static inline unsigned long
|
|
arm_gen_branch(unsigned long pc, unsigned long addr)
|
|
{
|
|
return __arm_gen_branch(pc, addr, false);
|
|
}
|
|
|
|
static inline unsigned long
|
|
arm_gen_branch_link(unsigned long pc, unsigned long addr)
|
|
{
|
|
return __arm_gen_branch(pc, addr, true);
|
|
}
|
|
|
|
#endif
|