linux-kernel - Re: [PATCH 02/11] riscv: update asm call site in `call_on_irq

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4ad699fc-a89d-4740-bdec-ecb9a2134c90@canonical.com>
Date: Fri, 25 Jul 2025 08:23:44 +0200
From: Heinrich Schuchardt <heinrich.schuchardt@...onical.com>
To: Deepak Gupta <debug@...osinc.com>
Cc: linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
 linux-kbuild@...r.kernel.org, linux-mm@...ck.org, llvm@...ts.linux.dev,
 rick.p.edgecombe@...el.com, broonie@...nel.org, cleger@...osinc.com,
 samitolvanen@...gle.com, apatel@...tanamicro.com, ajones@...tanamicro.com,
 conor.dooley@...rochip.com, charlie@...osinc.com, samuel.holland@...ive.com,
 bjorn@...osinc.com, fweimer@...hat.com, jeffreyalaw@...il.com,
 andrew@...ive.com, ved@...osinc.com, Paul Walmsley
 <paul.walmsley@...ive.com>, Palmer Dabbelt <palmer@...belt.com>,
 Albert Ou <aou@...s.berkeley.edu>, Alexandre Ghiti <alex@...ti.fr>,
 Masahiro Yamada <masahiroy@...nel.org>, Nathan Chancellor
 <nathan@...nel.org>, Nicolas Schier <nicolas.schier@...ux.dev>,
 Andrew Morton <akpm@...ux-foundation.org>,
 David Hildenbrand <david@...hat.com>,
 Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
 "Liam R. Howlett" <Liam.Howlett@...cle.com>, Vlastimil Babka
 <vbabka@...e.cz>, Mike Rapoport <rppt@...nel.org>,
 Suren Baghdasaryan <surenb@...gle.com>, Michal Hocko <mhocko@...e.com>,
 Nick Desaulniers <nick.desaulniers+lkml@...il.com>,
 Bill Wendling <morbo@...gle.com>, Monk Chiang <monk.chiang@...ive.com>,
 Kito Cheng <kito.cheng@...ive.com>, Justin Stitt <justinstitt@...gle.com>
Subject: Re: [PATCH 02/11] riscv: update asm call site in `call_on_irq_stack`
 to setup correct label

On 25.07.25 01:36, Deepak Gupta wrote:
> Call sites written in asm performing indirect call, they need to setup
> label register (t2/x7) with correct label.
> 
> Currently first kernel was compiled with `-save-temps` option and
> normalized function signature string is captured and then placed at the
> asm callsite.
> 
> TODO: to write a macro wrapper with toolchain support.
> 
> Signed-off-by: Deepak Gupta <debug@...osinc.com>
> ---
>   arch/riscv/kernel/entry.S | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
> index 2660faf52232..598e17e800ae 100644
> --- a/arch/riscv/kernel/entry.S
> +++ b/arch/riscv/kernel/entry.S
> @@ -389,6 +389,7 @@ SYM_FUNC_START(call_on_irq_stack)
>   	load_per_cpu t0, irq_stack_ptr, t1
>   	li	t1, IRQ_STACK_SIZE
>   	add	sp, t0, t1
> +	lui t2, %lpad_hash("FvP7pt_regsE")

In patch 1 you use lpad 0 due to missing tool support for signature hashing.

Wouldn't it be preferable to have a first patch series introducing 
landing pad support with lpad 0 and once tool support for signature 
hashing has landed create a second patch series using tags?

Such a first patch series would not have to be an RFC but might be 
merged soon.

Best regards

Heinrich

>   	jalr	a1
>   
>   	/* Switch back to the thread shadow call stack */
>