From: Andreas Schwab <schwab@suse.de>
To: Jisheng Zhang <jszhang@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] riscv: uaccess: use input constraints for ptr of __put_user
Date: Wed, 26 Jun 2024 15:35:54 +0200 [thread overview]
Message-ID: <mvma5j7omh1.fsf@suse.de> (raw)
In-Reply-To: <ZnwObmA70Bfx9yCn@xhacker> (Jisheng Zhang's message of "Wed, 26 Jun 2024 20:49:50 +0800")
On Jun 26 2024, Jisheng Zhang wrote:
> no output constraints either. It just uses "r" input constraints to tell
> gcc to read the store address into one proper GP reg.
Again, this is backwards. Being an input operand means the asm is using
this operand as an input to the instructions. The compiler needs to
arrange to put the value in the allocated operand location according to
the constraint.
--
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
next prev parent reply other threads:[~2024-06-26 13:36 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-25 4:04 [PATCH 0/4] riscv: uaccess: optimizations Jisheng Zhang
2024-06-25 4:04 ` [PATCH 1/4] riscv: implement user_access_begin and families Jisheng Zhang
2024-06-26 23:38 ` Cyril Bur
2024-06-25 4:04 ` [PATCH 2/4] riscv: uaccess: use input constraints for ptr of __put_user Jisheng Zhang
2024-06-25 5:54 ` Arnd Bergmann
2024-06-26 12:32 ` Jisheng Zhang
2024-06-26 12:49 ` Jisheng Zhang
2024-06-26 13:18 ` Jisheng Zhang
2024-06-26 13:35 ` Andreas Schwab [this message]
2024-06-26 13:54 ` Jisheng Zhang
2024-06-26 13:12 ` Andreas Schwab
2024-06-26 13:12 ` Jisheng Zhang
2024-06-26 14:25 ` Arnd Bergmann
2024-06-26 16:02 ` Jisheng Zhang
2024-06-27 6:46 ` Arnd Bergmann
2024-06-28 15:36 ` David Laight
2024-06-25 4:04 ` [PATCH 3/4] riscv: uaccess: use 'asm goto' for put_user() Jisheng Zhang
2024-07-05 2:22 ` kernel test robot
2024-07-06 0:02 ` kernel test robot
2024-06-25 4:05 ` [PATCH 4/4] riscv: uaccess: use 'asm goto output' for get_user Jisheng Zhang
2024-07-05 4:13 ` kernel test robot
2024-06-25 7:21 ` [PATCH 0/4] riscv: uaccess: optimizations Arnd Bergmann
2024-06-25 18:12 ` Linus Torvalds
2024-06-26 13:04 ` Jisheng Zhang
2024-06-30 16:59 ` Linus Torvalds
2024-07-05 11:25 ` Will Deacon
2024-07-05 17:58 ` Linus Torvalds
2024-07-08 13:52 ` Will Deacon
2024-07-08 15:30 ` Mark Rutland
2024-07-23 14:16 ` Will Deacon
2024-07-08 15:21 ` Mark Rutland
2024-07-24 22:57 ` Palmer Dabbelt
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=mvma5j7omh1.fsf@suse.de \
--to=schwab@suse.de \
--cc=aou@eecs.berkeley.edu \
--cc=arnd@arndb.de \
--cc=jszhang@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-riscv@lists.infradead.org \
--cc=palmer@dabbelt.com \
--cc=paul.walmsley@sifive.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