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-rw-r--r--arch/sparc/kernel/dtlb_prot.S55
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diff --git a/arch/sparc/kernel/dtlb_prot.S b/arch/sparc/kernel/dtlb_prot.S
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+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * dtlb_prot.S: DTLB protection trap strategy.
+ * This is included directly into the trap table.
+ *
+ * Copyright (C) 1996,1998 David S. Miller (davem@redhat.com)
+ * Copyright (C) 1997,1998 Jakub Jelinek (jj@ultra.linux.cz)
+ */
+
+/* Ways we can get here:
+ *
+ * [TL == 0] 1) User stores to readonly pages.
+ * [TL == 0] 2) Nucleus stores to user readonly pages.
+ * [TL > 0] 3) Nucleus stores to user readonly stack frame.
+ */
+
+/* PROT ** ICACHE line 1: User DTLB protection trap */
+ mov TLB_SFSR, %g1
+ stxa %g0, [%g1] ASI_DMMU ! Clear FaultValid bit
+ membar #Sync ! Synchronize stores
+ rdpr %pstate, %g5 ! Move into alt-globals
+ wrpr %g5, PSTATE_AG|PSTATE_MG, %pstate
+ rdpr %tl, %g1 ! Need a winfixup?
+ cmp %g1, 1 ! Trap level >1?
+ 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
+ srlx %g5, PAGE_SHIFT, %g5
+ sllx %g5, PAGE_SHIFT, %g5 ! Clear context ID bits
+ bgu,pn %xcc, winfix_trampoline ! Yes, perform winfixup
+ mov FAULT_CODE_DTLB | FAULT_CODE_WRITE, %g4
+ ba,pt %xcc, sparc64_realfault_common ! Nope, normal fault
+ nop
+ nop
+
+/* PROT ** ICACHE line 3: Unused... */
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+
+/* PROT ** ICACHE line 4: Unused... */
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop