From: Michael Ellerman Date: Mon, 20 Jun 2016 09:23:43 +0000 (+1000) Subject: powerpc: Fix faults caused by radix patching of SLB miss handler X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=6e914ee629c411d9c6d160399ce7d3472d2c0ec7;p=linux-beck.git powerpc: Fix faults caused by radix patching of SLB miss handler As part of the Radix MMU support we added some feature sections in the SLB miss handler. These are intended to catch the case that we incorrectly take an SLB miss when Radix is enabled, and instead of crashing weirdly they bail out to a well defined exit path and trigger an oops. However the way they were written meant the bailout case was enabled by default until we did CPU feature patching. On powermacs the early debug prints in setup_system() can cause an SLB miss, which happens before code patching, and so the SLB miss handler would incorrectly bailout and crash during boot. Fix it by inverting the sense of the feature section, so that the code which is in place at boot is correct for the hash case. Once we determine we are using Radix - which will never happen on a powermac - only then do we patch in the bailout case which unconditionally jumps. Fixes: caca285e5ab4 ("powerpc/mm/radix: Use STD_MMU_64 to properly isolate hash related code") Reported-by: Denis Kirjanov Tested-by: Denis Kirjanov Reviewed-by: Aneesh Kumar K.V Signed-off-by: Michael Ellerman --- diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index 4c9440629128..8bcc1b457115 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -1399,11 +1399,12 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_RADIX) lwz r9,PACA_EXSLB+EX_CCR(r13) /* get saved CR */ mtlr r10 -BEGIN_MMU_FTR_SECTION - b 2f -END_MMU_FTR_SECTION_IFSET(MMU_FTR_RADIX) andi. r10,r12,MSR_RI /* check for unrecoverable exception */ +BEGIN_MMU_FTR_SECTION beq- 2f +FTR_SECTION_ELSE + b 2f +ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_RADIX) .machine push .machine "power4"