Unbreak the nmi handler (again): I placed INTR_CLEAR_GPRS in the wrong

place and GS.base was horked on return.  Also, the frame passed to ddb
didn't have the %rbp<-->tf_err swap, which would have confused backtraces.
Now if we can just come up with a way to automate testing the NMI handler
with qemu...

diff --git a/sys/arch/amd64/amd64/vector.S b/sys/arch/amd64/amd64/vector.S
index 5bd8953..e06547f 100644 (file)
--- a/sys/arch/amd64/amd64/vector.S
+++ b/sys/arch/amd64/amd64/vector.S
@@ -1,4 +1,4 @@
-/*     $OpenBSD: vector.S,v 1.72 2018/07/12 14:11:11 guenther Exp $    */
+/*     $OpenBSD: vector.S,v 1.73 2018/07/12 14:24:54 guenther Exp $    */
 /*     $NetBSD: vector.S,v 1.5 2004/06/28 09:13:11 fvdl Exp $  */
 
 /*
@@ -121,7 +121,9 @@ IDTVEC(trap02)
        pushq   $0
        pushq   $T_NMI
 calltrap_specstk:                      # special stack path
-       INTR_REENTRY
+       INTR_ENTRY_KERN
+       INTR_SAVE_MOST_GPRS_NO_ADJ
+       INTR_CLEAR_GPRS
        movl    $MSR_GSBASE,%ecx        # save current GS.base...
        rdmsr
        movq    %rax,%r12               # ...in %r12 and %r13
@@ -139,7 +141,6 @@ calltrap_specstk:                   # special stack path
        .text
        .globl  INTRENTRY_LABEL(calltrap_specstk)
 INTRENTRY_LABEL(calltrap_specstk):
-       INTR_CLEAR_GPRS
        cld
        SMAP_CLAC
        movq    %rsp,%rdi
@@ -163,10 +164,11 @@ INTRENTRY_LABEL(calltrap_specstk):
 KUENTRY(calltrap_specstk_tramp)
        movq    %r15,%cr3               # restore %cr3
        popq    %r15
-       popq    %rbp
+       addq    $8,%rsp                 # ignore tf_err
        popq    %rbx
        popq    %rax
-       addq    $16,%rsp
+       addq    $8,%rsp                 # ignore tf_trapno
+       popq    %rbp
        iretq
 
 IDTVEC(trap03)