From: David S. Miller Date: Sun, 19 Oct 2014 03:03:09 +0000 (-0400) Subject: sparc64: Fix corrupted thread fault code. X-Git-Tag: v3.18-rc1~9^2~1 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=84bd6d8b9c0f06b3f188efb479c77e20f05e9a8a;p=profile%2Fcommon%2Fplatform%2Fkernel%2Flinux-artik7.git sparc64: Fix corrupted thread fault code. Every path that ends up at do_sparc64_fault() must install a valid FAULT_CODE_* bitmask in the per-thread fault code byte. Two paths leading to the label winfix_trampoline (which expects the FAULT_CODE_* mask in register %g4) were not doing so: 1) For pre-hypervisor TLB protection violation traps, if we took the 'winfix_trampoline' path we wouldn't have %g4 initialized with the FAULT_CODE_* value yet. Resulting in using the TLB_TAG_ACCESS register address value instead. 2) In the TSB miss path, when we notice that we are going to use a hugepage mapping, but we haven't allocated the hugepage TSB yet, we still have to take the window fixup case into consideration and in that particular path we leave %g4 not setup properly. Errors on this sort were largely invisible previously, but after commit 4ccb9272892c33ef1c19a783cfa87103b30c2784 ("sparc64: sun4v TLB error power off events") we now have a fault_code mask bit (FAULT_CODE_BAD_RA) that triggers due to this bug. FAULT_CODE_BAD_RA triggers because this bit is set in TLB_TAG_ACCESS (see #1 above) and thus we get seemingly random bus errors triggered for user processes. Fixes: 4ccb9272892c ("sparc64: sun4v TLB error power off events") Reported-by: Meelis Roos Signed-off-by: David S. Miller --- diff --git a/arch/sparc/kernel/dtlb_prot.S b/arch/sparc/kernel/dtlb_prot.S index b2c2c5b..d668ca14 100644 --- a/arch/sparc/kernel/dtlb_prot.S +++ b/arch/sparc/kernel/dtlb_prot.S @@ -24,11 +24,11 @@ mov TLB_TAG_ACCESS, %g4 ! For reload of vaddr /* PROT ** ICACHE line 2: More real fault processing */ + ldxa [%g4] ASI_DMMU, %g5 ! Put tagaccess in %g5 bgu,pn %xcc, winfix_trampoline ! Yes, perform winfixup - ldxa [%g4] ASI_DMMU, %g5 ! Put tagaccess in %g5 - ba,pt %xcc, sparc64_realfault_common ! Nope, normal fault mov FAULT_CODE_DTLB | FAULT_CODE_WRITE, %g4 - nop + ba,pt %xcc, sparc64_realfault_common ! Nope, normal fault + nop nop nop nop diff --git a/arch/sparc/kernel/tsb.S b/arch/sparc/kernel/tsb.S index 14158d4..be98685 100644 --- a/arch/sparc/kernel/tsb.S +++ b/arch/sparc/kernel/tsb.S @@ -162,10 +162,10 @@ tsb_miss_page_table_walk_sun4v_fastpath: nop .previous - rdpr %tl, %g3 - cmp %g3, 1 + rdpr %tl, %g7 + cmp %g7, 1 bne,pn %xcc, winfix_trampoline - nop + mov %g3, %g4 ba,pt %xcc, etrap rd %pc, %g7 call hugetlb_setup