Preserve pcb_onfault in kdbpeek() and kdbpoke()

This avoids misbehaviour if kdbpeek() or kdbpoke() is used in the middle
of a guarded copy operation.

diff --git a/sys/arch/mips64/mips64/lcore_ddb.S b/sys/arch/mips64/mips64/lcore_ddb.S
index 7c40b93..e80ccb6 100644 (file)
--- a/sys/arch/mips64/mips64/lcore_ddb.S
+++ b/sys/arch/mips64/mips64/lcore_ddb.S
@@ -1,4 +1,4 @@
-/*     $OpenBSD: lcore_ddb.S,v 1.14 2017/04/30 16:45:45 mpi Exp $ */
+/*     $OpenBSD: lcore_ddb.S,v 1.15 2022/01/25 07:08:43 visa Exp $ */
 
 /*
  * Copyright (c) 2001-2003 Opsycon AB  (www.opsycon.se / www.opsycon.com)
@@ -45,66 +45,70 @@ LEAF(kdbpeekd, 0)
        GET_CPU_INFO(t1, t0)
        PTR_L   t0, CI_CURPROCPADDR(t1)
        li      v0, KT_DDBERR
+       lw      t1, PCB_ONFAULT(t0)
        and     v1, a0, 7                       # unaligned ?
        bne     v1, zero, 1f
         sw     v0, PCB_ONFAULT(t0)
 
        ld      v0, (a0)
        jr      ra
-        sw     zero, PCB_ONFAULT(t0)
+        sw     t1, PCB_ONFAULT(t0)
 
 1:
        LDHI    v0, 0(a0)
        LDLO    v0, 7(a0)
        jr      ra
-        sw     zero, PCB_ONFAULT(t0)
+        sw     t1, PCB_ONFAULT(t0)
 END(kdbpeekd)
 
 LEAF(kdbpeek, 0)
        GET_CPU_INFO(t1, t0)
        PTR_L   t0, CI_CURPROCPADDR(t1)
        li      v0, KT_DDBERR
+       lw      t1, PCB_ONFAULT(t0)
        and     v1, a0, 3                       # unaligned ?
        bne     v1, zero, 1f
         sw     v0, PCB_ONFAULT(t0)
 
        lwu     v0, (a0)
        jr      ra
-        sw     zero, PCB_ONFAULT(t0)
+        sw     t1, PCB_ONFAULT(t0)
 
 1:
        LWHI    v0, 0(a0)
        LWLO    v0, 3(a0)
        jr      ra
-        sw     zero, PCB_ONFAULT(t0)
+        sw     t1, PCB_ONFAULT(t0)
 END(kdbpeek)
 
 LEAF(kdbpeekw, 0)
        GET_CPU_INFO(t1, t0)
        PTR_L   t0, CI_CURPROCPADDR(t1)
        li      v0, KT_DDBERR
+       lw      t1, PCB_ONFAULT(t0)
        and     v1, a0, 1                       # unaligned ?
        bne     v1, zero, 1f
         sw     v0, PCB_ONFAULT(t0)
 
        lh      v0, (a0)
        jr      ra
-        sw     zero, PCB_ONFAULT(t0)
+        sw     t1, PCB_ONFAULT(t0)
 
 1:
        li      v0, -1                          # error!
        jr      ra
-        sw     zero, PCB_ONFAULT(t0)
+        sw     t1, PCB_ONFAULT(t0)
 END(kdbpeekw)
 
 LEAF(kdbpeekb, 0)
        GET_CPU_INFO(t1, t0)
        PTR_L   t0, CI_CURPROCPADDR(t1)
        li      v0, KT_DDBERR
+       lw      t1, PCB_ONFAULT(t0)
        sw      v0, PCB_ONFAULT(t0)
        lb      v0, 0(a0)
        jr      ra
-        sw     zero, PCB_ONFAULT(t0)
+        sw     t1, PCB_ONFAULT(t0)
 END(kdbpeekb)
 
        .globl  kt_ddberr
@@ -116,65 +120,69 @@ LEAF(kdbpoked, 0)
        GET_CPU_INFO(t1, t0)
        PTR_L   t0, CI_CURPROCPADDR(t1)
        li      v0, KT_DDBERR
+       lw      t1, PCB_ONFAULT(t0)
        and     v1, a0, 7                       # unaligned ?
        bne     v1, zero, 1f
         sw     v0, PCB_ONFAULT(t0)
 
        sd      a1, (a0)
        jr      ra
-        sw     zero, PCB_ONFAULT(t0)
+        sw     t1, PCB_ONFAULT(t0)
 
 1:
        SDHI    a1, 0(a0)
        SDLO    a1, 7(a0)
        jr      ra
-        sw     zero, PCB_ONFAULT(t0)
+        sw     t1, PCB_ONFAULT(t0)
 END(kdbpoked)
 
 LEAF(kdbpoke, 0)
        GET_CPU_INFO(t1, t0)
        PTR_L   t0, CI_CURPROCPADDR(t1)
        li      v0, KT_DDBERR
+       lw      t1, PCB_ONFAULT(t0)
        and     v1, a0, 3                       # unaligned ?
        bne     v1, zero, 1f
         sw     v0, PCB_ONFAULT(t0)
 
        sw      a1, (a0)
        jr      ra
-        sw     zero, PCB_ONFAULT(t0)
+        sw     t1, PCB_ONFAULT(t0)
 
 1:
        SWHI    a1, 0(a0)
        SWLO    a1, 3(a0)
        jr      ra
-        sw     zero, PCB_ONFAULT(t0)
+        sw     t1, PCB_ONFAULT(t0)
 END(kdbpoke)
 
 LEAF(kdbpokew, 0)
        GET_CPU_INFO(t1, t0)
        PTR_L   t0, CI_CURPROCPADDR(t1)
        li      v0, KT_DDBERR
+       lw      t1, PCB_ONFAULT(t0)
        and     v1, a0, 1                       # unaligned ?
        bne     v1, zero, 1f
         sw     v0, PCB_ONFAULT(t0)
 
        sh      a1, (a0)
        jr      ra
-        sw     zero, PCB_ONFAULT(t0)
+        sw     t1, PCB_ONFAULT(t0)
 
 1:
        jr      ra
-        sw     zero, PCB_ONFAULT(t0)
+        sw     t1, PCB_ONFAULT(t0)
 END(kdbpokew)
 
 LEAF(kdbpokeb, 0)
        GET_CPU_INFO(t1, t0)
        PTR_L   t0, CI_CURPROCPADDR(t1)
        li      v0, KT_DDBERR
+       lw      t1, PCB_ONFAULT(t0)
        sw      v0, PCB_ONFAULT(t0)
        sb      a1, 0(a0)
        jr      ra
-        sw     zero, PCB_ONFAULT(t0)
+        sw     t1, PCB_ONFAULT(t0)
 END(kdbpokeb)
 
 LEAF(db_enter, 0)