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From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: x86@kernel.org, andrew.cooper3@citrix.com,
	linux-kernel@vger.kernel.org, alexei.starovoitov@gmail.com,
	ndesaulniers@google.com
Subject: Re: [PATCH 3/9] x86/asm: Fix register order
Date: Wed, 13 Oct 2021 13:15:58 -0700	[thread overview]
Message-ID: <20211013201558.xwvsisgnrirbbckf@treble> (raw)
In-Reply-To: <20211013123644.882036544@infradead.org>

On Wed, Oct 13, 2021 at 02:22:20PM +0200, Peter Zijlstra wrote:
> Ensure the register order is correct; this allows for easy translation
> between register number and trampoline and vice-versa.
> 
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>

It would be wise to add a comment saying the register order is critical
to the functioning of the system and shouldn't be changed.

> ---
>  arch/x86/include/asm/GEN-for-each-reg.h |   10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> --- a/arch/x86/include/asm/GEN-for-each-reg.h
> +++ b/arch/x86/include/asm/GEN-for-each-reg.h
> @@ -1,11 +1,12 @@
>  #ifdef CONFIG_64BIT
>  GEN(rax)
> -GEN(rbx)
>  GEN(rcx)
>  GEN(rdx)
> +GEN(rbx)
> +GEN(rsp)
> +GEN(rbp)
>  GEN(rsi)
>  GEN(rdi)
> -GEN(rbp)
>  GEN(r8)
>  GEN(r9)
>  GEN(r10)
> @@ -16,10 +17,11 @@ GEN(r14)
>  GEN(r15)
>  #else
>  GEN(eax)
> -GEN(ebx)
>  GEN(ecx)
>  GEN(edx)
> +GEN(ebx)
> +GEN(esp)
> +GEN(ebp)
>  GEN(esi)
>  GEN(edi)
> -GEN(ebp)
>  #endif

-- 
Josh


  reply	other threads:[~2021-10-13 20:16 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-13 12:22 [PATCH 0/9] x86: Rewrite the retpoline rewrite logic Peter Zijlstra
2021-10-13 12:22 ` [PATCH 1/9] objtool,x86: Replace alternatives with .retpoline_sites Peter Zijlstra
2021-10-13 13:29   ` Borislav Petkov
2021-10-13 20:11   ` Josh Poimboeuf
2021-10-14 15:43     ` Peter Zijlstra
2021-10-13 12:22 ` [PATCH 2/9] x86/retpoline: Remove unused replacement symbols Peter Zijlstra
2021-10-13 12:22 ` [PATCH 3/9] x86/asm: Fix register order Peter Zijlstra
2021-10-13 20:15   ` Josh Poimboeuf [this message]
2021-10-13 12:22 ` [PATCH 4/9] x86/alternative: Implement .retpoline_sites support Peter Zijlstra
2021-10-13 14:38   ` Andrew Cooper
2021-10-13 15:12     ` Peter Zijlstra
2021-10-13 17:11       ` Andrew Cooper
2021-10-14 10:05       ` Peter Zijlstra
2021-10-13 20:39   ` Josh Poimboeuf
2021-10-13 21:20     ` Peter Zijlstra
2021-10-13 21:49       ` Josh Poimboeuf
2021-10-13 21:52         ` Josh Poimboeuf
2021-10-13 22:10         ` Peter Zijlstra
2021-10-13 22:47           ` Andrew Cooper
2021-10-13 20:52   ` Josh Poimboeuf
2021-10-13 21:00     ` Peter Zijlstra
2021-10-19 11:37     ` Peter Zijlstra
2021-10-19 16:46       ` Josh Poimboeuf
2021-10-19 16:49         ` Josh Poimboeuf
2021-10-20  8:25           ` Peter Zijlstra
2021-10-20  8:30           ` Peter Zijlstra
2021-10-13 21:11   ` Josh Poimboeuf
2021-10-13 21:43     ` Peter Zijlstra
2021-10-13 22:05       ` Josh Poimboeuf
2021-10-13 22:14         ` Peter Zijlstra
2021-10-15 14:24   ` Borislav Petkov
2021-10-15 16:56     ` Peter Zijlstra
2021-10-18 23:06       ` Alexander Lobakin
2021-10-19  0:25         ` Alexander Lobakin
2021-10-19  9:47           ` Alexander Lobakin
2021-10-19 10:16             ` Peter Zijlstra
2021-10-19 15:37               ` Sami Tolvanen
2021-10-19 18:00                 ` Alexander Lobakin
2021-10-19  9:40         ` Peter Zijlstra
2021-10-19 10:02           ` Peter Zijlstra
2021-10-13 12:22 ` [PATCH 5/9] x86/alternative: Handle Jcc __x86_indirect_thunk_\reg Peter Zijlstra
2021-10-13 20:11   ` Nick Desaulniers
2021-10-13 21:08     ` Peter Zijlstra
2021-10-13 12:22 ` [PATCH 6/9] x86/alternative: Try inline spectre_v2=retpoline,amd Peter Zijlstra
2021-10-13 12:22 ` [PATCH 7/9] x86/alternative: Add debug prints to apply_retpolines() Peter Zijlstra
2021-10-13 12:22 ` [PATCH 8/9] x86,bugs: Unconditionally allow spectre_v2=retpoline,amd Peter Zijlstra
2021-10-13 12:22 ` [PATCH 9/9] bpf,x86: Respect X86_FEATURE_RETPOLINE* Peter Zijlstra
2021-10-13 21:06   ` Josh Poimboeuf
2021-10-13 21:54     ` Peter Zijlstra
2021-10-14  9:46       ` Peter Zijlstra
2021-10-14  9:48         ` Peter Zijlstra
2021-10-20  7:34         ` Peter Zijlstra

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