Commit 2400fd82 authored by Oliver O'Halloran's avatar Oliver O'Halloran Committed by Michael Ellerman

powerpc/asm: Mark cr0 as clobbered in mftb()

The workaround for the CELL timebase bug does not correctly mark cr0 as
being clobbered. This means GCC doesn't know that the asm block changes cr0 and
might leave the result of an unrelated comparison in cr0 across the block, which
we then trash, leading to basically random behaviour.

Fixes: 859deea9 ("[POWERPC] Cell timebase bug workaround")
Cc: stable@vger.kernel.org # v2.6.19+
Signed-off-by: default avatarOliver O'Halloran <oohall@gmail.com>
[mpe: Tweak change log and flag for stable]
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 41d0c2ec
...@@ -1303,7 +1303,7 @@ static inline void msr_check_and_clear(unsigned long bits) ...@@ -1303,7 +1303,7 @@ static inline void msr_check_and_clear(unsigned long bits)
" .llong 0\n" \ " .llong 0\n" \
".previous" \ ".previous" \
: "=r" (rval) \ : "=r" (rval) \
: "i" (CPU_FTR_CELL_TB_BUG), "i" (SPRN_TBRL)); \ : "i" (CPU_FTR_CELL_TB_BUG), "i" (SPRN_TBRL) : "cr0"); \
rval;}) rval;})
#else #else
#define mftb() ({unsigned long rval; \ #define mftb() ({unsigned long rval; \
......
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