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powerpc/book3s: Fix CFAR clobbering issue in machine check handler. 

While checking powersaving mode in machine check handler at 0x200, we
clobber CFAR register. Fix it by saving and restoring it during beq/bgt.

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Mahesh Salgaonkar 2014-03-11 10:56:18 +05:30 committed by Benjamin Herrenschmidt
parent 422b9b9684
commit d410ae2126
2 changed files with 13 additions and 0 deletions
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8
arch/powerpc/include/asm/exception-64s.h
View File

@ -146,6 +146,14 @@ BEGIN_FTR_SECTION_NESTED(943) \
mfspr ra,spr; \
END_FTR_SECTION_NESTED(ftr,ftr,943)
/*
* Set an SPR from a register if the CPU has the given feature
*/
#define OPT_SET_SPR(ra, spr, ftr) \
BEGIN_FTR_SECTION_NESTED(943) \
mtspr spr,ra; \
END_FTR_SECTION_NESTED(ftr,ftr,943)
/*
* Save a register to the PACA if the CPU has the given feature
*/

5
arch/powerpc/kernel/exceptions-64s.S
View File

@ -164,13 +164,18 @@ BEGIN_FTR_SECTION
*/
mfspr r13,SPRN_SRR1
rlwinm. r13,r13,47-31,30,31
OPT_GET_SPR(r13, SPRN_CFAR, CPU_FTR_CFAR)
beq 9f
mfspr r13,SPRN_SRR1
rlwinm. r13,r13,47-31,30,31
/* waking up from powersave (nap) state */
cmpwi cr1,r13,2
/* Total loss of HV state is fatal. let's just stay stuck here */
OPT_GET_SPR(r13, SPRN_CFAR, CPU_FTR_CFAR)
bgt cr1,.
9:
OPT_SET_SPR(r13, SPRN_CFAR, CPU_FTR_CFAR)
END_FTR_SECTION_IFSET(CPU_FTR_HVMODE | CPU_FTR_ARCH_206)
#endif /* CONFIG_PPC_P7_NAP */
EXCEPTION_PROLOG_0(PACA_EXMC)