From: Linus Walleij <linus.walleij@linaro.org>
To: Yan Zhao <yan.y.zhao@intel.com>
Cc: arnd@arndb.de, guoren@kernel.org, bcain@quicinc.com,
jonas@southpole.se, stefan.kristiansson@saunalahti.fi,
shorne@gmail.com, linux-arch@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-csky@vger.kernel.org,
linux-hexagon@vger.kernel.org, linux-openrisc@vger.kernel.org
Subject: Re: [PATCH] mm: Remove broken pfn_to_virt() on arch csky/hexagon/openrisc
Date: Fri, 2 Feb 2024 18:43:00 +0100 [thread overview]
Message-ID: <CACRpkdarfWFhvJ8vrDZXOk-nhDkgfwOLB+EytVm1S=-dEFKy3A@mail.gmail.com> (raw)
In-Reply-To: <20240202140550.9886-1-yan.y.zhao@intel.com>
On Fri, Feb 2, 2024 at 3:35 PM Yan Zhao <yan.y.zhao@intel.com> wrote:
> Remove the broken pfn_to_virt() on architectures csky/hexagon/openrisc.
>
> The pfn_to_virt() on those architectures takes PFN instead of PA as the
> input to macro __va(), with PAGE_SHIFT applying to the converted VA, which
> is not right, especially when there's a non-zero offset in __va(). [1]
>
> The broken pfn_to_virt() was noticed when checking how page_to_virt() is
> unfolded on x86. It turns out that the one in linux/mm.h instead of in
> asm-generic/page.h is compiled for x86. However, page_to_virt() in
> asm-generic/page.h is found out expanding to pfn_to_virt() with a bug
> described above. The pfn_to_virt() is found out not right as well on
> architectures csky/hexagon/openrisc.
>
> Since there's no single caller on csky/hexagon/openrisc to pfn_to_virt()
> and there are functions doing similar things as pfn_to_virt() --
> - pfn_to_kaddr() in asm/page.h for csky,
> - page_to_virt() in asm/page.h for hexagon, and
> - page_to_virt() in linux/mm.h for openrisc,
> just delete the pfn_to_virt() on those architectures.
>
> The pfn_to_virt() in asm-generic/page.h is not touched in this patch as
> it's referenced by page_to_virt() in that header while the whole header is
> going to be removed as a whole due to no one including it.
>
> Link:https://lore.kernel.org/all/20240131055159.2506-1-yan.y.zhao@intel.com [1]
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Suggested-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Thanks for making the kernel a better place!
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Yours,
Linus Walleij
prev parent reply other threads:[~2024-02-02 17:43 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-02 14:05 [PATCH] mm: Remove broken pfn_to_virt() on arch csky/hexagon/openrisc Yan Zhao
2024-02-02 16:10 ` Arnd Bergmann
2024-02-02 17:43 ` Linus Walleij [this message]
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='CACRpkdarfWFhvJ8vrDZXOk-nhDkgfwOLB+EytVm1S=-dEFKy3A@mail.gmail.com' \
--to=linus.walleij@linaro.org \
--cc=arnd@arndb.de \
--cc=bcain@quicinc.com \
--cc=guoren@kernel.org \
--cc=jonas@southpole.se \
--cc=linux-arch@vger.kernel.org \
--cc=linux-csky@vger.kernel.org \
--cc=linux-hexagon@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-openrisc@vger.kernel.org \
--cc=shorne@gmail.com \
--cc=stefan.kristiansson@saunalahti.fi \
--cc=yan.y.zhao@intel.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;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).