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From: Dominik Brodowski <linux@dominikbrodowski.net>
To: arjan@linux.intel.com, gregkh@linuxfoundation.org,
	mingo@kernel.org, dan.j.williams@intel.com, luto@kernel.org,
	bp@alien8.de, torvalds@linux-foundation.org, dwmw2@infradead.org,
	hpa@zytor.com, dave.hansen@linux.intel.com, jpoimboe@redhat.com,
	linux-kernel@vger.kernel.org, peterz@infradead.org,
	tglx@linutronix.de
Cc: linux-tip-commits@vger.kernel.org
Subject: Re: [tip:x86/pti] x86/entry: Reduce the code footprint of the 'idtentry' macro
Date: Sat, 17 Feb 2018 13:28:59 +0100	[thread overview]
Message-ID: <20180217122859.GA13344@isilmar-4.linta.de> (raw)
In-Reply-To: <tip-9e809d15d6b692fa061d74be7aaab1c79f6784b8@git.kernel.org>

On Sat, Feb 17, 2018 at 03:40:13AM -0800, tip-bot for Dominik Brodowski wrote:
> Commit-ID:  9e809d15d6b692fa061d74be7aaab1c79f6784b8
> Gitweb:     https://git.kernel.org/tip/9e809d15d6b692fa061d74be7aaab1c79f6784b8
> Author:     Dominik Brodowski <linux@dominikbrodowski.net>
> AuthorDate: Wed, 14 Feb 2018 18:59:23 +0100
> Committer:  Ingo Molnar <mingo@kernel.org>
> CommitDate: Sat, 17 Feb 2018 11:14:33 +0100
> 
> x86/entry: Reduce the code footprint of the 'idtentry' macro
> 
> Play a little trick in the generic PUSH_AND_CLEAR_REGS macro
> to insert the GP registers "above" the original return address.
> 
> This allows us to (re-)insert the macro in error_entry() and
> paranoid_entry() and to remove it from the idtentry macro. This
> reduces the static footprint significantly:
> 
>    text	   data	    bss	    dec	    hex	filename
>   24307	      0	      0	  24307	   5ef3	entry_64.o-orig
>   20987	      0	      0	  20987	   51fb	entry_64.o
> 
> Co-developed-by: Linus Torvalds <torvalds@linux-foundation.org>
> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
> Cc: Andy Lutomirski <luto@kernel.org>
> Cc: Arjan van de Ven <arjan@linux.intel.com>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Dave Hansen <dave.hansen@linux.intel.com>
> Cc: David Woodhouse <dwmw2@infradead.org>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Josh Poimboeuf <jpoimboe@redhat.com>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Link: http://lkml.kernel.org/r/20180214175924.23065-2-linux@dominikbrodowski.net
> [ Small tweaks to comments. ]
> Signed-off-by: Ingo Molnar <mingo@kernel.org>

Thanks! Just a minor thing:

> - * Switch gs if needed.
> + * Save all registers in pt_regs, and switch gs if needed.

...

> - * Switch gs if needed.
> + * Save all registers in pt_regs, and switch GS if needed.

If we switch from gs to GS, we should do it in both places.

Thanks!

	Dominik

  reply	other threads:[~2018-02-17 12:28 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-14 17:59 [PATCH 0/2] x86/entry: xorq->xorl; idtentry size reduction Dominik Brodowski
2018-02-14 17:59 ` [PATCH 1/2] x86/entry: reduce static footprint of idtentry Dominik Brodowski
2018-02-17 11:40   ` [tip:x86/pti] x86/entry: Reduce the code footprint of the 'idtentry' macro tip-bot for Dominik Brodowski
2018-02-17 12:28     ` Dominik Brodowski [this message]
2018-02-14 17:59 ` [PATCH 2/2] x86/entry/64: use xorl for register clearing Dominik Brodowski
2018-02-17 11:40   ` [tip:x86/pti] x86/entry/64: Use 'xorl' for faster " tip-bot for Dominik Brodowski

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