linux-kernel - Re: [PATCH v22 17/28] riscv/signal: save and restore of shadow stack for signal

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Message-ID: <d442965b-8716-4f89-be88-bc62459af712@infradead.org>
Date: Fri, 31 Oct 2025 15:10:01 -0700
From: Randy Dunlap <rdunlap@...radead.org>
To: Paul Walmsley <pjw@...nel.org>, Deepak Gupta <debug@...osinc.com>,
 Andy Chiu <andybnac@...il.com>
Cc: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
 Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>,
 x86@...nel.org, "H. Peter Anvin" <hpa@...or.com>,
 Andrew Morton <akpm@...ux-foundation.org>,
 "Liam R. Howlett" <Liam.Howlett@...cle.com>, Vlastimil Babka
 <vbabka@...e.cz>, Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
 Paul Walmsley <paul.walmsley@...ive.com>, Palmer Dabbelt
 <palmer@...belt.com>, Albert Ou <aou@...s.berkeley.edu>,
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Subject: Re: [PATCH v22 17/28] riscv/signal: save and restore of shadow stack
 for signal

On 10/31/25 1:07 PM, Paul Walmsley wrote:
> On Thu, 23 Oct 2025, Deepak Gupta via B4 Relay wrote:
> 
>> From: Deepak Gupta <debug@...osinc.com>
>>
>> Save shadow stack pointer in sigcontext structure while delivering signal.
>> Restore shadow stack pointer from sigcontext on sigreturn.
>>

> 
> This patch causes some 'checkpatch.pl --strict' messages:
> 
> CHECK: Comparison to NULL could be written "!saved_shstk_ptr"
> #271: FILE: arch/riscv/kernel/usercfi.c:186:
> +	if (saved_shstk_ptr == NULL)
> 
> CHECK: Lines should not end with a '('
> #300: FILE: arch/riscv/kernel/usercfi.c:215:
> +		pr_info_ratelimited(
> 
> I've fixed them up here in the event that v22 goes in, but please do the 
> same on your side in case a new version is needed.

Hi Paul,

Is checkpatch.pl --strict the norm for arch/riscv/ ?

If there are enough arch/riscv/-specific patch expectations,
maybe they could be documented in Documentation/process/maintainer-riscv.rst
(a new file).

Thanks.
-- 
~Randy