[patch 042/108] x86: memtest: remove 64-bit division

Greg KH
2009-07-01T00:58:26Z

[-- Attachment #1: x86-memtest-remove-64-bit-division.patch --]
[-- Type: text/plain, Size: 2174 bytes --]

2.6.30-stable review patch. If anyone has any objections, please let us know.

------------------

From: Andreas Herrmann <andreas.herrmann3@amd.com>

commit c9690998ef48ffefeccb91c70a7739eebdea57f9 upstream.

Using gcc 3.3.5 a "make allmodconfig" + "CONFIG_KVM=n"
triggers a build error:

arch/x86/mm/built-in.o(.init.text+0x43f7): In function `__change_page_attr':
arch/x86/mm/pageattr.c:114: undefined reference to `__udivdi3'
make: *** [.tmp_vmlinux1] Error 1

The culprit turned out to be a division in arch/x86/mm/memtest.c
For more info see this thread:

http://marc.info/?l=linux-kernel&m=124416232620683

The patch entirely removes the division that caused the build
error.

[ Impact: build fix with certain GCC versions ]

Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: xiyou.wangcong@gmail.com
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <20090608170939.GB12431@alberich.amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
arch/x86/mm/memtest.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

--- a/arch/x86/mm/memtest.c
+++ b/arch/x86/mm/memtest.c
@@ -40,23 +40,23 @@ static void __init reserve_bad_mem(u64 p

static void __init memtest(u64 pattern, u64 start_phys, u64 size)
{
- u64 i, count;
- u64 *start;
+ u64 *p;
+ void *start, *end;
u64 start_bad, last_bad;
u64 start_phys_aligned;
size_t incr;

incr = sizeof(pattern);
start_phys_aligned = ALIGN(start_phys, incr);
- count = (size - (start_phys_aligned - start_phys))/incr;
start = __va(start_phys_aligned);
+ end = start + size - (start_phys_aligned - start_phys);
start_bad = 0;
last_bad = 0;

- for (i = 0; i < count; i++)
- start[i] = pattern;
- for (i = 0; i < count; i++, start++, start_phys_aligned += incr) {
- if (*start == pattern)
+ for (p = start; p < end; p++)
+ *p = pattern;
+ for (p = start; p < end; p++, start_phys_aligned += incr) {
+ if (*p == pattern)
continue;
if (start_phys_aligned == last_bad + incr) {
last_bad += incr;