Re: [PATCH 1/5] x86: Implement __WARN using UD0

[Josh Poimboeuf]

On Wed, Mar 22, 2017 at 09:47:06AM +0100, Peter Zijlstra wrote:
> 
> A little like so then.
> 
> ---
> Subject: x86: Implement __WARN using UD0
> From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Date: Thu Feb 2 14:43:51 CET 2017
> 
> By using "UD0" for WARNs we remove the function call and its possible
> __FILE__ and __LINE__ immediate arguments from the instruction stream.
> 
> Total image size will not change much, what we win in the instruction
> stream we'll loose because of the __bug_table entries. Still, saves on
> I$ footprint and the total image size does go down a bit.
> 
>    text    data     bss     dec     hex filename
> 10702123        4530992  843776 16076891         f5505b defconfig-build/vmlinux.0
> 10682460        4530992  843776 16057228         f5038c defconfig-build/vmlinux.1
> 
> (um didn't seem to use GENERIC_BUG at all, so remove it)
> 
> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> Cc: Richard Weinberger <richard.weinberger@xxxxxxxxx>
> Cc: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>
> Cc: Borislav Petkov <bp@xxxxxxxxx>
> Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
> 
> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>

Looks good, thanks!

Reviewed-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>

-- 
Josh