[src/trunk]: src/sys/arch/i386/i386 Add double fault TSS stub code.

[fvdl <fvdl%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/5885ceb0be4a
branches:  trunk
changeset: 537790:5885ceb0be4a
user:      fvdl <fvdl%NetBSD.org@localhost>
date:      Sat Oct 05 21:20:00 2002 +0000

description:
Add double fault TSS stub code.

diffstat:

 sys/arch/i386/i386/locore.s |  35 +++++++++++++++++++++++++++++++++--
 1 files changed, 33 insertions(+), 2 deletions(-)

diffs (63 lines):

diff -r 50fe384e5344 -r 5885ceb0be4a sys/arch/i386/i386/locore.s
--- a/sys/arch/i386/i386/locore.s       Sat Oct 05 21:19:39 2002 +0000
+++ b/sys/arch/i386/i386/locore.s       Sat Oct 05 21:20:00 2002 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: locore.s,v 1.264 2002/10/04 06:43:40 junyoung Exp $    */
+/*     $NetBSD: locore.s,v 1.265 2002/10/05 21:20:00 fvdl Exp $        */
 
 /*-
  * Copyright (c) 1998, 2000 The NetBSD Foundation, Inc.
@@ -2263,6 +2263,24 @@
 #define        BPTTRAP(a)      ZTRAP(a)
 #endif
 
+/*
+ * Store address of TSS in %eax, given a selector in %eax.
+ * Clobbers %eax, %ecx, %edx, but that's ok for its usage.
+ * This is a bit complicated, but it's done to make as few
+ * assumptions as possible about the validity of the environment.
+ * The GDT and the current and previous TSS are known to be OK,
+ * otherwise we would not be here. The only other thing that needs
+ * to be OK is the cpu_info structure for the current CPU.
+ */
+#define GET_TSS \
+       andl    $0xfff8,%eax                            ;\
+       addl    CPUVAR(GDT),%eax                        ;\
+       movl    2(%eax),%edx                            ;\
+       andl    $0xffffff,%edx                          ;\
+       movzbl  7(%eax),%eax                            ;\
+       shl     $24,%eax                                ;\
+       orl     %edx,%eax
+
        .text
 IDTVEC(trap00)
        ZTRAP(T_DIVIDE)
@@ -2293,7 +2311,7 @@
        ZTRAP(T_DNA)
 #endif
 IDTVEC(trap08)
-       TRAP(T_DOUBLEFLT)
+       ZTRAP(T_DOUBLEFLT)
 IDTVEC(trap09)
        ZTRAP(T_FPOPFLT)
 IDTVEC(trap0a)
@@ -2388,6 +2406,19 @@
        .long   _C_LABEL(Xtrap1c), _C_LABEL(Xtrap1d)
        .long   _C_LABEL(Xtrap1e), _C_LABEL(Xtrap1f)
 
+IDTVEC(tss_trap08)
+1:
+       str     %ax
+       GET_TSS
+       movzwl  (%eax),%eax
+       GET_TSS
+       pushl   $T_DOUBLEFLT
+       pushl   %eax
+       call    _C_LABEL(trap_tss)
+       addl    $12,%esp
+       iret
+       jmp     1b
+
 /*
  * If an error is detected during trap, syscall, or interrupt exit, trap() will
  * change %eip to point to one of these labels.  We clean up the stack, if