From: Ingo Molnar <mingo@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
rostedt@goodmis.org, mhiramat@kernel.org, bristot@redhat.com,
jbaron@akamai.com, torvalds@linux-foundation.org,
tglx@linutronix.de, namit@vmware.com, hpa@zytor.com,
luto@kernel.org, ard.biesheuvel@linaro.org, jpoimboe@redhat.com,
jeyu@kernel.org
Subject: Re: [PATCH v4 09/16] x86/alternative: Remove text_poke_loc::len
Date: Mon, 21 Oct 2019 11:02:03 +0200 [thread overview]
Message-ID: <20191021090203.GA88859@gmail.com> (raw)
In-Reply-To: <20191021085830.GA102207@gmail.com>
* Ingo Molnar <mingo@kernel.org> wrote:
>
> * Peter Zijlstra <peterz@infradead.org> wrote:
>
> > * Second step: update all but the first byte of the patched range.
> > */
> > for (do_sync = 0, i = 0; i < nr_entries; i++) {
> > - if (tp[i].len - sizeof(int3) > 0) {
> > + int len = text_opcode_size(tp[i].opcode);
> > +
> > + if (len - sizeof(int3) > 0) {
> > text_poke((char *)tp[i].addr + sizeof(int3),
> > (const char *)tp[i].text + sizeof(int3),
> > - tp[i].len - sizeof(int3));
> > + len - sizeof(int3));
> > do_sync++;
> > }
>
> Readability side note: 'sizeof(int3)' is a really weird way to write '1'
> and I had to double check it's not measuring the size of some larger
> entity.
>
> I think it might make sense to just break out INT3_SIZE from
> arch/x86/kernel/kprobes/opt.c into a header, rename it to INS_INT3_SIZE
> and define it to 1, because the opt.c use is pretty obfuscated as well:
>
> #define INT3_SIZE sizeof(kprobe_opcode_t)
>
> Where kprobe_opcode_t is u8 on x86 (and won't ever be anything else).
>
> ?
Oh, the latter is done in your patch #11 already. Nice!
Thanks,
Ingo
next prev parent reply other threads:[~2019-10-21 9:02 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-18 7:35 [PATCH v4 00/16] Rewrite x86/ftrace to use text_poke (and more) Peter Zijlstra
2019-10-18 7:35 ` [PATCH v4 01/16] x86/alternatives: Teach text_poke_bp() to emulate instructions Peter Zijlstra
2019-10-18 7:35 ` [PATCH v4 02/16] x86/alternatives: Update int3_emulate_push() comment Peter Zijlstra
2019-10-18 7:35 ` [PATCH v4 03/16] x86/alternatives,jump_label: Provide better text_poke() batching interface Peter Zijlstra
2019-10-21 8:48 ` Ingo Molnar
2019-10-21 9:21 ` Peter Zijlstra
2019-10-18 7:35 ` [PATCH v4 04/16] x86/alternatives: Add and use text_gen_insn() helper Peter Zijlstra
2019-10-18 7:35 ` [PATCH v4 05/16] x86/ftrace: Use text_poke() Peter Zijlstra
2019-10-18 7:35 ` [PATCH v4 06/16] x86/mm: Remove set_kernel_text_r[ow]() Peter Zijlstra
2019-10-18 7:35 ` [PATCH v4 07/16] x86/alternative: Add text_opcode_size() Peter Zijlstra
2019-10-18 7:35 ` [PATCH v4 08/16] x86/ftrace: Use text_gen_insn() Peter Zijlstra
2019-10-18 7:35 ` [PATCH v4 09/16] x86/alternative: Remove text_poke_loc::len Peter Zijlstra
2019-10-21 8:58 ` Ingo Molnar
2019-10-21 9:02 ` Ingo Molnar [this message]
2019-10-18 7:35 ` [PATCH v4 10/16] x86/alternative: Shrink text_poke_loc Peter Zijlstra
2019-10-21 9:01 ` Ingo Molnar
2019-10-21 9:25 ` Peter Zijlstra
2019-10-21 9:33 ` Ingo Molnar
2019-10-18 7:35 ` [PATCH v4 11/16] x86/kprobes: Convert to text-patching.h Peter Zijlstra
2019-10-21 14:57 ` Masami Hiramatsu
2019-10-18 7:35 ` [PATCH v4 12/16] x86/kprobes: Fix ordering Peter Zijlstra
2019-10-22 1:35 ` Masami Hiramatsu
2019-10-22 10:31 ` Peter Zijlstra
2019-10-18 7:35 ` [PATCH v4 13/16] arm/ftrace: Use __patch_text_real() Peter Zijlstra
2019-10-28 16:25 ` Will Deacon
2019-10-28 16:34 ` Peter Zijlstra
2019-10-28 16:35 ` Peter Zijlstra
2019-10-28 16:47 ` Will Deacon
2019-10-28 16:55 ` Peter Zijlstra
2019-10-18 7:35 ` [PATCH v4 14/16] module: Remove set_all_modules_text_*() Peter Zijlstra
2019-10-18 7:35 ` [PATCH v4 15/16] module: Move where we mark modules RO,X Peter Zijlstra
2019-10-21 13:53 ` Josh Poimboeuf
2019-10-21 14:14 ` Peter Zijlstra
2019-10-21 15:34 ` Peter Zijlstra
2019-10-21 15:44 ` Peter Zijlstra
2019-10-21 16:11 ` Peter Zijlstra
2019-10-22 11:31 ` Heiko Carstens
2019-10-22 12:31 ` Peter Zijlstra
2019-10-23 11:48 ` Peter Zijlstra
2019-10-23 15:16 ` Peter Zijlstra
2019-10-23 17:15 ` Josh Poimboeuf
2019-10-24 10:59 ` Peter Zijlstra
2019-10-24 18:31 ` Josh Poimboeuf
2019-10-24 20:33 ` Peter Zijlstra
2019-10-23 17:00 ` Josh Poimboeuf
2019-10-24 13:16 ` Peter Zijlstra
2019-10-25 6:44 ` Petr Mladek
2019-10-25 8:43 ` Peter Zijlstra
2019-10-25 10:06 ` Peter Zijlstra
2019-10-25 13:50 ` Josh Poimboeuf
2019-10-26 1:17 ` Josh Poimboeuf
2019-10-28 10:07 ` Peter Zijlstra
2019-10-28 10:43 ` Peter Zijlstra
2019-10-25 9:16 ` Peter Zijlstra
2019-10-22 2:21 ` Steven Rostedt
2019-10-22 20:24 ` Peter Zijlstra
2019-10-22 20:40 ` Steven Rostedt
2019-10-23 9:07 ` Peter Zijlstra
2019-10-23 18:52 ` Steven Rostedt
2019-10-24 10:16 ` Peter Zijlstra
2019-10-24 10:18 ` Peter Zijlstra
2019-10-24 15:00 ` Steven Rostedt
2019-10-24 16:43 ` Peter Zijlstra
2019-10-24 18:17 ` Steven Rostedt
2019-10-24 20:24 ` Peter Zijlstra
2019-10-24 20:28 ` Steven Rostedt
2019-10-18 7:35 ` [PATCH v4 16/16] ftrace: Merge ftrace_module_{init,enable}() Peter Zijlstra
2019-10-18 8:20 ` Peter Zijlstra
2019-10-21 9:09 ` [PATCH v4 00/16] Rewrite x86/ftrace to use text_poke (and more) Ingo Molnar
2019-10-21 13:38 ` Steven Rostedt
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