From: Masami Hiramatsu <mhiramat@kernel.org>
To: Ingo Molnar <mingo@kernel.org>, Steven Rostedt <rostedt@goodmis.org>
Cc: mhiramat@kernel.org, linux-kernel@vger.kernel.org,
"Naveen N . Rao" <naveen.n.rao@linux.ibm.com>,
Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
David Miller <davem@davemloft.net>,
Borislav Petkov <bp@alien8.de>,
x86@kernel.org
Subject: [PATCH 0/1] x86/kprobes: Classify opcode while preparing kprobe
Date: Sun, 6 Dec 2020 23:11:28 +0900 [thread overview]
Message-ID: <160726388853.3413805.4854581312983421622.stgit@devnote2> (raw)
Hi,
I noticed that the kprobe x86 still has an inefficient code.
Currently kprobes x86 decodes opcode right after single
stepping in resume_execution(), which is kprobe's hot path.
But it already decoded the opcode while preparing
arch_specific_insn in arch_copy_kprobe(), so this is
inefficient.
So decode the opcode while preparing kprobes (arch_copy_kprobe())
instead of resume_execution() and set some flags for resuming from
single stepping. This also removes the custom instruction prefix
decoding, which should be done in x86 instruction decoder.
Thank you,
---
Masami Hiramatsu (1):
x86/kprobes: Do not decode opcode in resume_execution()
arch/x86/include/asm/kprobes.h | 11 ++-
arch/x86/kernel/kprobes/core.c | 166 ++++++++++++++++++----------------------
2 files changed, 80 insertions(+), 97 deletions(-)
--
Masami Hiramatsu (Linaro) <mhiramat@kernel.org>
next reply other threads:[~2020-12-06 14:12 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-06 14:11 Masami Hiramatsu [this message]
2020-12-06 14:11 ` [PATCH 1/1] x86/kprobes: Do not decode opcode in resume_execution() Masami Hiramatsu
2020-12-07 20:28 ` Steven Rostedt
2020-12-18 1:02 ` [x86/kprobes] 413d31338f: kernel_BUG_at_mm/vmalloc.c kernel test robot
2020-12-18 12:44 ` Masami Hiramatsu
2020-12-18 14:12 ` [PATCH -tip v2] x86/kprobes: Do not decode opcode in resume_execution() Masami Hiramatsu
2020-12-31 16:09 ` Borislav Petkov
2021-01-04 3:45 ` Masami Hiramatsu
2021-01-04 18:40 ` Borislav Petkov
2021-01-05 14:47 ` [tip: perf/kprobes] " tip-bot2 for Masami Hiramatsu
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