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84bd6d8b9c
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 commit4ccb927289("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:4ccb927289("sparc64: sun4v TLB error power off events") Reported-by: Meelis Roos <mroos@linux.ee> Signed-off-by: David S. Miller <davem@davemloft.net>
55 lines
1.2 KiB
ArmAsm
55 lines
1.2 KiB
ArmAsm
/*
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* dtlb_prot.S: DTLB protection trap strategy.
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* This is included directly into the trap table.
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*
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* Copyright (C) 1996,1998 David S. Miller (davem@redhat.com)
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* Copyright (C) 1997,1998 Jakub Jelinek (jj@ultra.linux.cz)
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*/
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/* Ways we can get here:
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*
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* [TL == 0] 1) User stores to readonly pages.
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* [TL == 0] 2) Nucleus stores to user readonly pages.
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* [TL > 0] 3) Nucleus stores to user readonly stack frame.
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*/
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/* PROT ** ICACHE line 1: User DTLB protection trap */
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mov TLB_SFSR, %g1
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stxa %g0, [%g1] ASI_DMMU ! Clear FaultValid bit
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membar #Sync ! Synchronize stores
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rdpr %pstate, %g5 ! Move into alt-globals
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wrpr %g5, PSTATE_AG|PSTATE_MG, %pstate
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rdpr %tl, %g1 ! Need a winfixup?
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cmp %g1, 1 ! Trap level >1?
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mov TLB_TAG_ACCESS, %g4 ! For reload of vaddr
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/* PROT ** ICACHE line 2: More real fault processing */
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ldxa [%g4] ASI_DMMU, %g5 ! Put tagaccess in %g5
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bgu,pn %xcc, winfix_trampoline ! Yes, perform winfixup
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mov FAULT_CODE_DTLB | FAULT_CODE_WRITE, %g4
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ba,pt %xcc, sparc64_realfault_common ! Nope, normal fault
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nop
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nop
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nop
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nop
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/* PROT ** ICACHE line 3: Unused... */
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nop
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nop
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nop
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nop
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nop
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nop
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nop
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nop
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/* PROT ** ICACHE line 4: Unused... */
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nop
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nop
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nop
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nop
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nop
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nop
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nop
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nop
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