Revision bdbc29c19b2633b1d9c52638fb732bcde7a2031a authored by Paul Mackerras on 27 August 2013, 06:07:49 UTC, committed by Benjamin Herrenschmidt on 27 August 2013, 06:59:30 UTC
On 64-bit, __pa(&static_var) gets miscompiled by recent versions of gcc as something like: addis 3,2,.LANCHOR1+4611686018427387904@toc@ha addi 3,3,.LANCHOR1+4611686018427387904@toc@l This ends up effectively ignoring the offset, since its bottom 32 bits are zero, and means that the result of __pa() still has 0xC in the top nibble. This happens with gcc 4.8.1, at least. To work around this, for 64-bit we make __pa() use an AND operator, and for symmetry, we make __va() use an OR operator. Using an AND operator rather than a subtraction ends up with slightly shorter code since it can be done with a single clrldi instruction, whereas it takes three instructions to form the constant (-PAGE_OFFSET) and add it on. (Note that MEMORY_START is always 0 on 64-bit.) CC: <stable@vger.kernel.org> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
1 parent f5f6cbb
File | Mode | Size |
---|---|---|
Documentation | ||
arch | ||
block | ||
crypto | ||
drivers | ||
firmware | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.gitignore | -rw-r--r-- | 1.1 KB |
.mailmap | -rw-r--r-- | 4.4 KB |
COPYING | -rw-r--r-- | 18.3 KB |
CREDITS | -rw-r--r-- | 93.1 KB |
Kbuild | -rw-r--r-- | 2.5 KB |
Kconfig | -rw-r--r-- | 252 bytes |
MAINTAINERS | -rw-r--r-- | 253.7 KB |
Makefile | -rw-r--r-- | 47.4 KB |
README | -rw-r--r-- | 18.3 KB |
REPORTING-BUGS | -rw-r--r-- | 7.3 KB |
![swh spinner](/static/img/swh-spinner.gif)
Computing file changes ...