From: Geert Uytterhoeven <geert@linux-m68k.org>
To: linux-m68k@vger.kernel.org
Cc: Martijn Coenen <maco@android.com>,
Christoph Hellwig <hch@infradead.org>,
linux-kernel@vger.kernel.org,
Geert Uytterhoeven <geert@linux-m68k.org>
Subject: [PATCH] m68k/uaccess: Revive 64-bit get_user()
Date: Mon, 14 May 2018 15:57:15 +0200 [thread overview]
Message-ID: <1526306235-29755-1-git-send-email-geert@linux-m68k.org> (raw)
Revive support for 64-bit get_user(), which was disabled in commit
d94af931af42152e ("[PATCH] m68k: clean up uaccess.h") due to a "broken"
typeof in (then brand new) gcc-4.1.
- Keep on using u64 for the temporary, as __typeof__() doesn't drop
the const qualifier,
- Move it into a union (like mips32 does) to get rid of the cast, as
using get_user() to fetch a __user pointer would cause a "cast to
pointer from integer of different size" warning otherwise.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
arch/m68k/include/asm/uaccess_mm.h | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/arch/m68k/include/asm/uaccess_mm.h b/arch/m68k/include/asm/uaccess_mm.h
index 75c172e909acdf18..c4cb889660aa0c35 100644
--- a/arch/m68k/include/asm/uaccess_mm.h
+++ b/arch/m68k/include/asm/uaccess_mm.h
@@ -141,10 +141,12 @@ asm volatile ("\n" \
case 4: \
__get_user_asm(__gu_err, x, ptr, u32, l, r, -EFAULT); \
break; \
-/* case 8: disabled because gcc-4.1 has a broken typeof \
- { \
- const void *__gu_ptr = (ptr); \
- u64 __gu_val; \
+ case 8: { \
+ const void *__gu_ptr = (ptr); \
+ union { \
+ u64 l; \
+ __typeof__(*(ptr)) t; \
+ } __gu_val; \
asm volatile ("\n" \
"1: "MOVES".l (%2)+,%1\n" \
"2: "MOVES".l (%2),%R1\n" \
@@ -162,13 +164,13 @@ asm volatile ("\n" \
" .long 1b,10b\n" \
" .long 2b,10b\n" \
" .previous" \
- : "+d" (__gu_err), "=&r" (__gu_val), \
+ : "+d" (__gu_err), "=&r" (__gu_val.l), \
"+a" (__gu_ptr) \
: "i" (-EFAULT) \
: "memory"); \
- (x) = (__force typeof(*(ptr)))__gu_val; \
+ (x) = __gu_val.t; \
break; \
- } */ \
+ } \
default: \
__gu_err = __get_user_bad(); \
break; \
--
2.7.4
next reply other threads:[~2018-05-14 13:57 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-14 13:57 Geert Uytterhoeven [this message]
2018-05-14 21:34 ` [PATCH] m68k/uaccess: Revive 64-bit get_user() Martijn Coenen
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=1526306235-29755-1-git-send-email-geert@linux-m68k.org \
--to=geert@linux-m68k.org \
--cc=hch@infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-m68k@vger.kernel.org \
--cc=maco@android.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 NNTP newsgroup(s).