Linux-RISC-V Archive on lore.kernel.org
 help / color / mirror / Atom feed
From: "Arnd Bergmann" <arnd@arndb.de>
To: "Harshal Dev" <harshal.dev@oss.qualcomm.com>,
	"Jens Wiklander" <jens.wiklander@linaro.org>,
	"Arnd Bergmann" <arnd@kernel.org>
Cc: "Paul Walmsley" <pjw@kernel.org>,
	"Palmer Dabbelt" <palmer@dabbelt.com>,
	"Albert Ou" <aou@eecs.berkeley.edu>,
	"Amirreza Zarrabi" <amirreza.zarrabi@oss.qualcomm.com>,
	"Sumit Garg" <sumit.garg@oss.qualcomm.com>,
	"Sumit Garg" <sumit.garg@kernel.org>,
	"Alexandre Ghiti" <alex@ghiti.fr>,
	"Etienne Carriere" <etienne.carriere@foss.st.com>,
	"Randy Dunlap" <rdunlap@infradead.org>,
	op-tee@lists.trustedfirmware.org, linux-kernel@vger.kernel.org,
	linux-riscv@lists.infradead.org
Subject: Re: [PATCH] tee: fix tee_ioctl_object_invoke_arg padding
Date: Fri, 05 Dec 2025 14:56:21 +0100	[thread overview]
Message-ID: <9e44024d-a649-49d6-825f-97f2a11e1691@app.fastmail.com> (raw)
In-Reply-To: <45b5f14b-3746-4b05-a4b4-dc9f88e89e52@oss.qualcomm.com>

On Fri, Dec 5, 2025, at 14:45, Harshal Dev wrote:
> On 12/4/2025 6:57 PM, Jens Wiklander wrote:
>> On Thu, Dec 4, 2025 at 11:17 AM Arnd Bergmann <arnd@kernel.org> wrote:
>> 
> The only user-space client which is currently using this ABI (as per 
> our knowledge)
> is the libqcomtee library: 
> https://github.com/quic/quic-teec/blob/main/libqcomtee/src/linux/tee.h#L432
>
> If I understand Arnd's concern correctly, if a compiler used to build 
> the user-space
> client skips the padding for tee_ioctl_object_invoke_arg, it could lead 
> to issues.
>
> Let's wait for Amir's view here as well, however I do think the 
> explicit padding would
> benefit here.
>

The problem is much narrower: as the amount of padding is determined
by the architecture specific ABI, kernel and userspace on the same
architecture always agree, and specifically 32-bit Arm userspace
and 64-bit Arm userspace (aarch64) also have the same rules, so there
is no problem on Qualcomm's platforms even with compat 32-bit userspace.

The only actual ABI problem would happen on 32-bit x86 (i386)
userspace running on a 64-bit x86 kernel, since i386-linux compilers
have different alignment rules from most other architectures.

        Arnd

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

  reply	other threads:[~2025-12-05 13:57 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-12-04 10:17 [PATCH] tee: fix tee_ioctl_object_invoke_arg padding Arnd Bergmann
2025-12-04 13:27 ` Jens Wiklander
2025-12-05 13:45   ` Harshal Dev
2025-12-05 13:56     ` Arnd Bergmann [this message]
2025-12-05 14:11       ` Harshal Dev
2025-12-08  5:24   ` Amirreza Zarrabi
2025-12-08 12:20     ` Sumit Garg
2025-12-08 12:54       ` Harshal Dev
2025-12-09  3:54         ` Amirreza Zarrabi
2025-12-16  7:48           ` Jens Wiklander
2025-12-16 10:55             ` Harshal Dev
2025-12-16 13:17               ` Jens Wiklander
2026-04-27 11:41                 ` Jens Wiklander

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=9e44024d-a649-49d6-825f-97f2a11e1691@app.fastmail.com \
    --to=arnd@arndb.de \
    --cc=alex@ghiti.fr \
    --cc=amirreza.zarrabi@oss.qualcomm.com \
    --cc=aou@eecs.berkeley.edu \
    --cc=arnd@kernel.org \
    --cc=etienne.carriere@foss.st.com \
    --cc=harshal.dev@oss.qualcomm.com \
    --cc=jens.wiklander@linaro.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-riscv@lists.infradead.org \
    --cc=op-tee@lists.trustedfirmware.org \
    --cc=palmer@dabbelt.com \
    --cc=pjw@kernel.org \
    --cc=rdunlap@infradead.org \
    --cc=sumit.garg@kernel.org \
    --cc=sumit.garg@oss.qualcomm.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox