From: Borislav Petkov <bp@suse.de>
To: Andy Lutomirski <luto@kernel.org>
Cc: X86 ML <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Brian Gerst <brgerst@gmail.com>,
Dave Hansen <dave.hansen@intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 05/18] x86/asm/64: Shrink paranoid_exit_restore and make labels local
Date: Fri, 27 Oct 2017 22:07:15 +0200 [thread overview]
Message-ID: <20171027200715.GB12039@nazgul.tnic> (raw)
In-Reply-To: <fbaf2584562ec39dfba5ec8cb1666af11ee27943.1509006199.git.luto@kernel.org>
On Thu, Oct 26, 2017 at 01:26:37AM -0700, Andy Lutomirski wrote:
> paranoid_exit_restore was a copy of
> restore_regs_and_return_to_kernel. Merge them and make the
> paranoid_exit internal labels local.
>
> Keeping .Lparanoid_exit makes the code a bit shorter because it
> allows a 2-byte jnz instead of a 5-byte jnz.
>
> Saves 96 bytes of text.
>
> (This is still a bit suboptimal in a non-CONFIG_TRACE_IRQFLAGS
> kernel, but fixing that would make the code rather messy.)
>
> Signed-off-by: Andy Lutomirski <luto@kernel.org>
> ---
> arch/x86/entry/entry_64.S | 13 +++++--------
> 1 file changed, 5 insertions(+), 8 deletions(-)
>
> diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
> index 4ad40067162a..d6404a613df4 100644
> --- a/arch/x86/entry/entry_64.S
> +++ b/arch/x86/entry/entry_64.S
> @@ -1119,17 +1119,14 @@ ENTRY(paranoid_exit)
> DISABLE_INTERRUPTS(CLBR_ANY)
> TRACE_IRQS_OFF_DEBUG
> testl %ebx, %ebx /* swapgs needed? */
> - jnz paranoid_exit_no_swapgs
> + jnz .Lparanoid_exit_no_swapgs
> TRACE_IRQS_IRETQ
> SWAPGS_UNSAFE_STACK
> - jmp paranoid_exit_restore
> -paranoid_exit_no_swapgs:
> + jmp .Lparanoid_exit_restore
Kill that paranoid_exit_restore too and save everybody a jump:
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 1b9e8079ca3a..b88e17e120fa 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1122,10 +1122,9 @@ ENTRY(paranoid_exit)
jnz .Lparanoid_exit_no_swapgs
TRACE_IRQS_IRETQ
SWAPGS_UNSAFE_STACK
- jmp .Lparanoid_exit_restore
+ jmp restore_regs_and_return_to_kernel
.Lparanoid_exit_no_swapgs:
TRACE_IRQS_IRETQ_DEBUG
-.Lparanoid_exit_restore:
jmp restore_regs_and_return_to_kernel
END(paranoid_exit)
--
Regards/Gruss,
Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--
next prev parent reply other threads:[~2017-10-27 20:07 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-26 8:26 [PATCH 00/18] Pile o' entry/exit/sp0 changes Andy Lutomirski
2017-10-26 8:26 ` [PATCH 01/18] x86/asm/64: Remove the restore_c_regs_and_iret label Andy Lutomirski
2017-10-26 15:07 ` Borislav Petkov
2017-11-10 6:08 ` [01/18] " kemi
2017-10-26 8:26 ` [PATCH 02/18] x86/asm/64: Split the iret-to-user and iret-to-kernel paths Andy Lutomirski
2017-10-27 18:05 ` Dave Hansen
2017-11-01 11:34 ` Andy Lutomirski
2017-10-27 20:04 ` Borislav Petkov
2017-11-01 11:32 ` Andy Lutomirski
2017-10-26 8:26 ` [PATCH 03/18] x86/asm/64: Move SWAPGS into the common iret-to-usermode path Andy Lutomirski
2017-10-26 13:52 ` Brian Gerst
2017-10-26 14:13 ` Dave Hansen
2017-10-26 14:28 ` Borislav Petkov
2017-10-27 15:44 ` Andy Lutomirski
2017-10-27 18:08 ` Dave Hansen
2017-10-26 8:26 ` [PATCH 04/18] x86/asm/64: Simplify reg restore code in the standard IRET paths Andy Lutomirski
2017-10-26 8:26 ` [PATCH 05/18] x86/asm/64: Shrink paranoid_exit_restore and make labels local Andy Lutomirski
2017-10-27 20:07 ` Borislav Petkov [this message]
2017-10-26 8:26 ` [PATCH 06/18] x86/asm/64: Use pop instead of movq in syscall_return_via_sysret Andy Lutomirski
2017-10-27 20:11 ` Borislav Petkov
2017-10-26 8:26 ` [PATCH 07/18] x86/asm/64: Merge the fast and slow SYSRET paths Andy Lutomirski
2017-10-27 20:11 ` Borislav Petkov
2017-11-01 11:29 ` Andy Lutomirski
2017-11-01 12:35 ` Borislav Petkov
2017-11-01 17:26 ` Thomas Gleixner
2017-11-01 17:25 ` Brian Gerst
2017-11-01 20:35 ` Andy Lutomirski
2017-10-26 8:26 ` [PATCH 08/18] xen: add xen nmi trap entry Andy Lutomirski
2017-10-26 8:26 ` [PATCH 09/18] x86/asm/64: De-Xen-ify our NMI code Andy Lutomirski
2017-10-26 8:41 ` Juergen Gross
2017-10-27 20:11 ` Borislav Petkov
2017-10-26 8:26 ` [PATCH 10/18] x86/asm/32: Pull MSR_IA32_SYSENTER_CS update code out of native_load_sp0() Andy Lutomirski
2017-10-26 18:00 ` Brian Gerst
2017-10-27 13:51 ` Thomas Gleixner
2017-10-27 15:50 ` Andy Lutomirski
2017-10-27 20:11 ` Borislav Petkov
2017-10-26 8:26 ` [PATCH 11/18] x86/asm/64: Pass sp0 directly to load_sp0() Andy Lutomirski
2017-10-27 20:12 ` Borislav Petkov
2017-10-26 8:26 ` [PATCH 12/18] x86/asm: Add task_top_of_stack() to find the top of a task's stack Andy Lutomirski
2017-10-26 8:26 ` [PATCH 13/18] x86/xen/64: Clean up SP code in cpu_initialize_context() Andy Lutomirski
2017-10-26 8:43 ` Juergen Gross
2017-10-26 8:26 ` [PATCH 14/18] x86/boot/64: Stop initializing TSS.sp0 at boot Andy Lutomirski
2017-10-27 18:21 ` Dave Hansen
2017-10-28 8:10 ` Andy Lutomirski
2017-10-26 8:26 ` [PATCH 15/18] x86/asm/64: Remove all remaining direct thread_struct::sp0 reads Andy Lutomirski
2017-11-01 10:08 ` Borislav Petkov
2017-10-26 8:26 ` [PATCH 16/18] x86/boot/32: Fix cpu_current_top_of_stack initialization at boot Andy Lutomirski
2017-11-01 10:18 ` Borislav Petkov
2017-10-26 8:26 ` [PATCH 17/18] x86/asm/64: Remove thread_struct::sp0 Andy Lutomirski
2017-10-28 0:52 ` Brian Gerst
2017-11-01 10:23 ` Borislav Petkov
2017-11-01 10:40 ` Andy Lutomirski
2017-10-26 8:26 ` [PATCH 18/18] x86/traps: Use a new on_thread_stack() helper to clean up an assertion Andy Lutomirski
2017-11-01 10:31 ` Borislav Petkov
2017-11-01 10:45 ` Andy Lutomirski
2017-10-26 15:55 ` [PATCH 00/18] Pile o' entry/exit/sp0 changes Linus Torvalds
2017-10-28 7:31 ` Andy Lutomirski
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=20171027200715.GB12039@nazgul.tnic \
--to=bp@suse.de \
--cc=brgerst@gmail.com \
--cc=dave.hansen@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@kernel.org \
--cc=torvalds@linux-foundation.org \
--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).