diff options
| author | Anton Blanchard <anton@samba.org> | 2012-09-03 16:51:10 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-09-14 10:00:49 -0700 |
| commit | 7b296be56d7355e6cbf340a1f6a567810ba4c32c (patch) | |
| tree | 987a882735af88a66ee5ea13e9e86df196e70eca /arch/powerpc/kernel/asm-offsets.c | |
| parent | 52640dfe68118991369cae14e7877caa2e8ef7a7 (diff) | |
powerpc: Restore correct DSCR in context switch
commit 714332858bfd40dcf8f741498336d93875c23aa7 upstream.
During a context switch we always restore the per thread DSCR value.
If we aren't doing explicit DSCR management
(ie thread.dscr_inherit == 0) and the default DSCR changed while
the process has been sleeping we end up with the wrong value.
Check thread.dscr_inherit and select the default DSCR or per thread
DSCR as required.
This was found with the following test case, when running with
more threads than CPUs (ie forcing context switching):
http://ozlabs.org/~anton/junkcode/dscr_default_test.c
With the four patches applied I can run a combination of all
test cases successfully at the same time:
http://ozlabs.org/~anton/junkcode/dscr_default_test.c
http://ozlabs.org/~anton/junkcode/dscr_explicit_test.c
http://ozlabs.org/~anton/junkcode/dscr_inherit_test.c
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/powerpc/kernel/asm-offsets.c')
| -rw-r--r-- | arch/powerpc/kernel/asm-offsets.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index 36e1c8a29be..4c12a751bea 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -75,6 +75,7 @@ int main(void) DEFINE(SIGSEGV, SIGSEGV); DEFINE(NMI_MASK, NMI_MASK); DEFINE(THREAD_DSCR, offsetof(struct thread_struct, dscr)); + DEFINE(THREAD_DSCR_INHERIT, offsetof(struct thread_struct, dscr_inherit)); #else DEFINE(THREAD_INFO, offsetof(struct task_struct, stack)); #endif /* CONFIG_PPC64 */ |