From: Steven Rostedt <rostedt@goodmis.org>
To: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Jiri Kosina <jkosina@suse.cz>,
Josh Poimboeuf <jpoimboe@redhat.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Chris von Recklinghausen <crecklin@redhat.com>,
Jason Baron <jbaron@akamai.com>, Scott Wood <swood@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
Clark Williams <williams@redhat.com>,
x86@kernel.org
Subject: Re: [PATCH V4 5/9] x86/alternative: Split text_poke_bp() into tree steps
Date: Thu, 7 Feb 2019 19:15:52 -0500 [thread overview]
Message-ID: <20190207191552.0782a29d@gandalf.local.home> (raw)
In-Reply-To: <cf7096ad15708be48f3ea62b4e903f6ef29e2838.1549308412.git.bristot@redhat.com>
On Mon, 4 Feb 2019 20:58:58 +0100
Daniel Bristot de Oliveira <bristot@redhat.com> wrote:
>
> +static void text_poke_bp_set_handler(void *addr, void *handler,
> + unsigned char int3)
> +{
> + bp_int3_handler = handler;
> + bp_int3_addr = (u8 *)addr + sizeof(int3);
> + text_poke(addr, &int3, sizeof(int3));
> +}
> +
> +
> +static void patch_first_byte(void *addr, const void *opcode, unsigned char int3)
> +{
> + /* patch the first byte */
> + text_poke(addr, opcode, sizeof(int3));
> +}
Hmm, perhaps get rid of the first function entirely, and just do...
(although why have the "int3" here anyway?)
> +
> /**
> * text_poke_bp() -- update instructions on live kernel on SMP
> * @addr: address to patch
> @@ -791,27 +814,21 @@ void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler)
> {
> unsigned char int3 = 0xcc;
>
> - bp_int3_handler = handler;
> - bp_int3_addr = (u8 *)addr + sizeof(int3);
> - bp_patching_in_progress = true;
> -
> lockdep_assert_held(&text_mutex);
>
> + bp_patching_in_progress = true;
> /*
> * Corresponding read barrier in int3 notifier for making sure the
> * in_progress and handler are correctly ordered wrt. patching.
> */
> smp_wmb();
>
> - text_poke(addr, &int3, sizeof(int3));
> + text_poke_bp_set_handler(addr, handler, int3);
patch_first_byte(addr, &int3, int3);
Which could be just:
patch_first_byte(addr, &int3);
if we remove passing in int3 (for its size?).
-- Steve
>
> on_each_cpu(do_sync_core, NULL, 1);
>
> if (len - sizeof(int3) > 0) {
> - /* patch all but the first byte */
> - text_poke((char *)addr + sizeof(int3),
> - (const char *) opcode + sizeof(int3),
> - len - sizeof(int3));
> + patch_all_but_first_byte(addr, opcode, len, int3);
> /*
> * According to Intel, this core syncing is very likely
> * not necessary and we'd be safe even without it. But
> @@ -820,8 +837,7 @@ void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler)
> on_each_cpu(do_sync_core, NULL, 1);
> }
>
> - /* patch the first byte */
> - text_poke(addr, opcode, sizeof(int3));
> + patch_first_byte(addr, opcode, int3);
>
> on_each_cpu(do_sync_core, NULL, 1);
> /*
next prev parent reply other threads:[~2019-02-08 0:15 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-04 19:58 [PATCH V4 0/9] x86/jump_label: Bound IPIs sent when updating a static key Daniel Bristot de Oliveira
2019-02-04 19:58 ` [PATCH V4 1/9] jump_label: Add for_each_label_entry helper Daniel Bristot de Oliveira
2019-02-04 19:58 ` [PATCH V4 2/9] jump_label: Add the jump_label_can_update_check() helper Daniel Bristot de Oliveira
2019-02-05 7:22 ` Borislav Petkov
2019-02-05 13:50 ` Daniel Bristot de Oliveira
2019-02-05 21:13 ` Borislav Petkov
2019-02-07 13:21 ` Daniel Bristot de Oliveira
2019-02-07 14:08 ` Borislav Petkov
2019-02-07 17:00 ` Daniel Bristot de Oliveira
2019-02-07 17:08 ` Borislav Petkov
2019-02-04 19:58 ` [PATCH V4 3/9] x86/jump_label: Move checking code away from __jump_label_transform() Daniel Bristot de Oliveira
2019-02-05 7:33 ` Borislav Petkov
2019-02-05 15:22 ` Daniel Bristot de Oliveira
2019-02-15 10:05 ` Daniel Bristot de Oliveira
2019-02-04 19:58 ` [PATCH V4 4/9] x86/jump_label: Add __jump_label_set_jump_code() helper Daniel Bristot de Oliveira
2019-02-04 19:58 ` [PATCH V4 5/9] x86/alternative: Split text_poke_bp() into tree steps Daniel Bristot de Oliveira
2019-02-06 19:07 ` Borislav Petkov
2019-02-08 0:11 ` Steven Rostedt
2019-02-08 0:15 ` Steven Rostedt [this message]
2019-02-15 12:47 ` Daniel Bristot de Oliveira
2019-02-21 15:26 ` Steven Rostedt
2019-02-04 19:58 ` [PATCH V4 6/9] jump_label: Sort entries of the same key by the code Daniel Bristot de Oliveira
2019-02-04 19:59 ` [PATCH V4 7/9] x86/alternative: Batch of patch operations Daniel Bristot de Oliveira
2019-02-14 12:53 ` Borislav Petkov
2019-02-14 14:06 ` Steven Rostedt
2019-02-14 14:30 ` Borislav Petkov
2019-02-14 14:40 ` Steven Rostedt
2019-02-14 14:54 ` Borislav Petkov
2019-02-15 16:00 ` Daniel Bristot de Oliveira
2019-02-15 17:20 ` Steven Rostedt
2019-02-04 19:59 ` [PATCH V4 8/9] jump_label: Batch updates if arch supports it Daniel Bristot de Oliveira
2019-02-06 6:34 ` Masami Hiramatsu
2019-02-06 15:59 ` Daniel Bristot de Oliveira
2019-02-14 13:33 ` Borislav Petkov
2019-02-04 19:59 ` [PATCH V4 9/9] x86/jump_label: Batch jump label updates Daniel Bristot de Oliveira
2019-02-06 6:29 ` Masami Hiramatsu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190207191552.0782a29d@gandalf.local.home \
--to=rostedt@goodmis.org \
--cc=bp@alien8.de \
--cc=bristot@redhat.com \
--cc=crecklin@redhat.com \
--cc=gregkh@linuxfoundation.org \
--cc=hpa@zytor.com \
--cc=jbaron@akamai.com \
--cc=jkosina@suse.cz \
--cc=jpoimboe@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mhiramat@kernel.org \
--cc=mingo@redhat.com \
--cc=mtosatti@redhat.com \
--cc=peterz@infradead.org \
--cc=swood@redhat.com \
--cc=tglx@linutronix.de \
--cc=williams@redhat.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).