From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Benjamin LaHaise <bcrl@kvack.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Linux-Next <linux-next@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: linux-next: build failure after merge of the aio tree
Date: Thu, 4 Feb 2016 14:12:53 +0000 [thread overview]
Message-ID: <20160204141253.GF10826@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <20160204140822.GB16315@kvack.org>
On Thu, Feb 04, 2016 at 09:08:22AM -0500, Benjamin LaHaise wrote:
> On Thu, Feb 04, 2016 at 01:50:56PM +0000, Russell King - ARM Linux wrote:
> > > I am still convinced that this is an architecture issue. Given that 64 bit
> > > values work in the *get_user implementations on other architectures, I see
> > > no reason there should need to be a workaround for this in common code.
> >
> > So you're happy to break x86-32 then...
>
> x86-32 works fine.
Let me repeat the quote from my previous email:
#define __get_user(x, ptr) \
__get_user_nocheck((x), (ptr), sizeof(*(ptr)))
#define __get_user_nocheck(x, ptr, size) \
({ \
int __gu_err; \
unsigned long __gu_val; \
__uaccess_begin(); \
__get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \
__uaccess_end(); \
(x) = (__force __typeof__(*(ptr)))__gu_val; \
__builtin_expect(__gu_err, 0); \
})
#define __get_user_size(x, ptr, size, retval, errret) \
do { \
retval = 0; \
__chk_user_ptr(ptr); \
switch (size) { \
case 1: \
__get_user_asm(x, ptr, retval, "b", "b", "=q", errret); \
break; \
case 2: \
__get_user_asm(x, ptr, retval, "w", "w", "=r", errret); \
break; \
case 4: \
__get_user_asm(x, ptr, retval, "l", "k", "=r", errret); \
break; \
case 8: \
__get_user_asm_u64(x, ptr, retval, errret); \
break; \
default: \
(x) = __get_user_bad(); \
} \
} while (0)
#ifdef CONFIG_X86_32
#define __get_user_asm_u64(x, ptr, retval, errret) (x) = __get_user_bad()
#define __get_user_asm_ex_u64(x, ptr) (x) = __get_user_bad()
#else
#define __get_user_asm_u64(x, ptr, retval, errret) \
__get_user_asm(x, ptr, retval, "q", "", "=r", errret)
#define __get_user_asm_ex_u64(x, ptr) \
__get_user_asm_ex(x, ptr, "q", "", "=r")
#endif
Hence, __get_user() on x86-32 with a 64-bit quantity results in
__get_user_bad() being called, which is an undefined function.
Only if you build with x86-64 support enabled (iow, CONFIG_X86_32 not
defined) then you get the 64-bit __get_user() support.
Given this, I fail to see how x86-32 can possibly work.
--
RMK's Patch system: http://www.arm.linux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
next prev parent reply other threads:[~2016-02-04 14:13 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-12 5:40 linux-next: build failure after merge of the aio tree Stephen Rothwell
2016-01-12 16:38 ` Benjamin LaHaise
2016-01-27 2:40 ` Stephen Rothwell
2016-01-29 11:30 ` Russell King - ARM Linux
2016-01-29 12:03 ` Geert Uytterhoeven
2016-02-04 2:19 ` Stephen Rothwell
2016-02-04 13:41 ` Benjamin LaHaise
2016-02-04 13:50 ` Russell King - ARM Linux
2016-02-04 14:08 ` Benjamin LaHaise
2016-02-04 14:12 ` Russell King - ARM Linux [this message]
2016-02-04 14:32 ` Benjamin LaHaise
2016-02-04 14:39 ` Russell King - ARM Linux
2016-02-04 16:01 ` Benjamin LaHaise
2016-02-04 16:17 ` Russell King - ARM Linux
2016-02-04 16:27 ` Benjamin LaHaise
2016-02-04 16:47 ` Benjamin LaHaise
2016-02-04 18:48 ` Benjamin LaHaise
2016-01-15 2:24 ` Stephen Rothwell
2016-01-15 7:39 ` Christoph Hellwig
2016-01-15 9:23 ` Stephen Rothwell
2016-01-15 9:25 ` Christoph Hellwig
2016-01-15 15:18 ` Benjamin LaHaise
2016-01-15 22:55 ` Stephen Rothwell
2016-03-14 4:49 ` Stephen Rothwell
2016-03-14 17:08 ` Benjamin LaHaise
2016-03-14 20:41 ` Stephen Rothwell
-- strict thread matches above, loose matches on Subject: below --
2016-03-15 6:46 Stephen Rothwell
2016-03-15 14:38 ` Andy Shevchenko
2016-03-15 16:42 ` Arnd Bergmann
2016-03-15 16:19 ` Sudip Mukherjee
2016-03-15 16:22 ` Benjamin LaHaise
2016-03-15 22:02 ` Arnd Bergmann
2016-03-16 11:12 ` Andy Shevchenko
2016-03-16 13:59 ` Arnd Bergmann
2016-03-16 14:07 ` Benjamin LaHaise
2013-08-30 7:55 Stephen Rothwell
2013-08-30 14:26 ` Benjamin LaHaise
2013-08-30 17:38 ` Linus Torvalds
2013-08-30 17:42 ` Benjamin LaHaise
2013-08-21 7:45 Stephen Rothwell
2013-08-21 15:52 ` Dave Kleikamp
2013-08-21 23:53 ` Stephen Rothwell
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