diff options
authorDavid S. Miller <davem@davemloft.net>2014-10-18 23:03:09 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-10-30 09:40:19 -0700
commita5fb600211af8749bc81c7697d7f48ce100d278e (patch)
parentac1addf5ab3a937de68cd1460460dee3aa7271c7 (diff)
sparc64: Fix corrupted thread fault code.
[ Upstream commit 84bd6d8b9c0f06b3f188efb479c77e20f05e9a8a ] 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 <mroos@linux.ee> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2 files changed, 6 insertions, 6 deletions
diff --git a/arch/sparc/kernel/dtlb_prot.S b/arch/sparc/kernel/dtlb_prot.S
index b2c2c5be281c..d668ca149e64 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
- nop
+ ba,pt %xcc, sparc64_realfault_common ! Nope, normal fault
+ nop
diff --git a/arch/sparc/kernel/tsb.S b/arch/sparc/kernel/tsb.S
index 14158d40ba76..be98685c14c6 100644
--- a/arch/sparc/kernel/tsb.S
+++ b/arch/sparc/kernel/tsb.S
@@ -162,10 +162,10 @@ tsb_miss_page_table_walk_sun4v_fastpath:
- 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