From: will.deacon@arm•com (Will Deacon)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] ARM64: disable DCACHE_WORD_ACCESS in big endian case
Date: Wed, 23 Apr 2014 13:38:45 +0100 [thread overview]
Message-ID: <20140423123845.GB5649@arm.com> (raw)
In-Reply-To: <CAA3XUr20eFyLshVM+7VBSMz4a4-cCA0PLrYGN5oyk-wOM2NLtg@mail.gmail.com>
On Wed, Apr 23, 2014 at 07:37:11AM +0100, Victor Kamensky wrote:
> Hi Will,
Hi Victor,
Thanks for investigating this!
> On 22 April 2014 02:46, Will Deacon <will.deacon@arm•com> wrote:
> > On Mon, Apr 21, 2014 at 11:36:10PM +0100, Victor Kamensky wrote:
> The issue turned out to be in another commit: "word-at-a-time:
> provide generic big-endian zero_bytemask implementation". Because
> of the issue in zero_bytemask function full_name_hash and
> hash_name were giving different hash results for the same path
> name (without slash). The issue is that (~0ul << 64) gives
> ~0ul not 0. I could not come up with more elegant solution other
> than use inline function that check shift value against type maximum
> width. Please take a look below.
Ah yes, we're in UNDEFINED territory here and AArch64 differs from AArch32
wrt LSL >= register width. Can you try the following instead of your patch
please? I think it should be more efficient.
Cheers,
Will
--->8
diff --git a/include/asm-generic/word-at-a-time.h b/include/asm-generic/word-at-a-time.h
index d3909effd725..243ce8c84ee9 100644
--- a/include/asm-generic/word-at-a-time.h
+++ b/include/asm-generic/word-at-a-time.h
@@ -50,11 +50,7 @@ static inline bool has_zero(unsigned long val, unsigned long *data, const struct
}
#ifndef zero_bytemask
-#ifdef CONFIG_64BIT
-#define zero_bytemask(mask) (~0ul << fls64(mask))
-#else
-#define zero_bytemask(mask) (~0ul << fls(mask))
-#endif /* CONFIG_64BIT */
+#define zero_bytemask(mask) (mask ? ~0ul << __fls(mask) << 1 : ~0ul)
#endif /* zero_bytemask */
#endif /* _ASM_WORD_AT_A_TIME_H */
next prev parent reply other threads:[~2014-04-23 12:38 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-21 22:36 [PATCH] ARM64: disable DCACHE_WORD_ACCESS in big endian case Victor Kamensky
2014-04-22 9:46 ` Will Deacon
2014-04-23 6:37 ` Victor Kamensky
2014-04-23 12:38 ` Will Deacon [this message]
2014-04-23 16:22 ` Victor Kamensky
2014-04-23 16:37 ` Will Deacon
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=20140423123845.GB5649@arm.com \
--to=will.deacon@arm$(echo .)com \
--cc=linux-arm-kernel@lists$(echo .)infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
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