https://github.com/torvalds/linux
Revision 208fae5c3b9431013ad7bcea07cbcee114e7d163 authored by Nicolas Pitre on 14 March 2016, 01:55:45 UTC, committed by Russell King on 07 April 2016, 20:57:02 UTC
It was reported that a kernel with CONFIG_ARM_PATCH_IDIV=y stopped booting when compiled with the upcoming gcc 6. Turns out that turning a function address into a writable array is undefined and gcc 6 decided it was OK to omit the store to the first word of the function while still preserving the store to the second word. Even though gcc 6 is now fixed to behave more coherently, it is a mystery that gcc 4 and gcc 5 actually produce wanted code in the kernel. And in fact the reduced test case to illustrate the issue does indeed break with gcc < 6 as well. In any case, let's guard the kernel against undefined compiler behavior by hiding the nature of the array location as suggested by gcc developers. Reference: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70128 Signed-off-by: Nicolas Pitre <nico@linaro.org> Reported-by: Marcin Juszkiewicz <mjuszkiewicz@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: stable@vger.kernel.org # v4.5 Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
1 parent f2335a2
Tip revision: 208fae5c3b9431013ad7bcea07cbcee114e7d163 authored by Nicolas Pitre on 14 March 2016, 01:55:45 UTC
ARM: 8550/1: protect idiv patching against undefined gcc behavior
ARM: 8550/1: protect idiv patching against undefined gcc behavior
Tip revision: 208fae5
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arch | ||
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certs | ||
crypto | ||
drivers | ||
firmware | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.get_maintainer.ignore | -rw-r--r-- | 31 bytes |
.gitignore | -rw-r--r-- | 1.2 KB |
.mailmap | -rw-r--r-- | 5.5 KB |
COPYING | -rw-r--r-- | 18.3 KB |
CREDITS | -rw-r--r-- | 95.4 KB |
Kbuild | -rw-r--r-- | 2.6 KB |
Kconfig | -rw-r--r-- | 252 bytes |
MAINTAINERS | -rw-r--r-- | 343.4 KB |
Makefile | -rw-r--r-- | 55.0 KB |
README | -rw-r--r-- | 18.1 KB |
REPORTING-BUGS | -rw-r--r-- | 7.3 KB |
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