From: Borislav Petkov <bp@alien8.de>
To: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
"Steven Rostedt (VMware)" <rostedt@goodmis.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 3/9] x86/jump_label: Move checking code away from __jump_label_transform()
Date: Tue, 5 Feb 2019 08:33:21 +0100 [thread overview]
Message-ID: <20190205073321.GE21801@zn.tnic> (raw)
In-Reply-To: <10e6ab5f9481a5a51bd6dd6c818453908ea60777.1549308412.git.bristot@redhat.com>
On Mon, Feb 04, 2019 at 08:58:56PM +0100, Daniel Bristot de Oliveira wrote:
> Move the check of the current code, before updating an entry, to specialized
> functions. No changes in the method, only code relocation.
>
> Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Masami Hiramatsu <mhiramat@kernel.org>
> Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> Cc: Jiri Kosina <jkosina@suse.cz>
> Cc: Josh Poimboeuf <jpoimboe@redhat.com>
> Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
> Cc: Chris von Recklinghausen <crecklin@redhat.com>
> Cc: Jason Baron <jbaron@akamai.com>
> Cc: Scott Wood <swood@redhat.com>
> Cc: Marcelo Tosatti <mtosatti@redhat.com>
> Cc: Clark Williams <williams@redhat.com>
> Cc: x86@kernel.org
> Cc: linux-kernel@vger.kernel.org
> ---
> arch/x86/kernel/jump_label.c | 60 +++++++++++++++++++++++++-----------
> 1 file changed, 42 insertions(+), 18 deletions(-)
>
> diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c
> index f99bd26bd3f1..e443c43478eb 100644
> --- a/arch/x86/kernel/jump_label.c
> +++ b/arch/x86/kernel/jump_label.c
> @@ -35,16 +35,53 @@ static void bug_at(unsigned char *ip, int line)
> BUG();
> }
>
> +static inline void __jump_label_trans_check_enable(struct jump_entry *entry,
> + enum jump_label_type type,
> + const unsigned char *ideal_nop,
> + int init)
> +{
> + const unsigned char default_nop[] = { STATIC_KEY_INIT_NOP };
> + const void *expect;
> + int line;
> +
> + if (init) {
> + expect = default_nop; line = __LINE__;
> + } else {
> + expect = ideal_nop; line = __LINE__;
> + }
> +
> + if (memcmp((void *)jump_entry_code(entry), expect, JUMP_LABEL_NOP_SIZE))
> + bug_at((void *)jump_entry_code(entry), line);
> +}
> +
> +static inline void __jump_label_trans_check_disable(struct jump_entry *entry,
> + enum jump_label_type type,
> + union jump_code_union *jmp,
> + int init)
> +{
> + const unsigned char default_nop[] = { STATIC_KEY_INIT_NOP };
> + const void *expect;
> + int line;
> +
> + if (init) {
> + expect = default_nop; line = __LINE__;
> + } else {
> + expect = jmp->code; line = __LINE__;
> + }
> +
> + if (memcmp((void *)jump_entry_code(entry), expect, JUMP_LABEL_NOP_SIZE))
> + bug_at((void *)jump_entry_code(entry), line);
> +}
Why the carve out?
The next patch is adding __jump_label_set_jump_code() which calls them
so you could just as well keep the functionality all in that function without
having too many helpers which are called only once...
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
next prev parent reply other threads:[~2019-02-05 7:33 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 [this message]
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
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
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