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Enable CR0_AM on 486s. (We already handled the fault.) This would be more 

useful if it applied to the kernel.
Avoid btrl when checking AST flag.
Add hooks to recover from errors during any INTRFASTEXIT and simulate a user-
level protection fault.
This commit is contained in:
mycroft 1995-01-15 00:52:21 +00:00
parent c26ad3af41
commit 3e8850eab2
1 changed files with 26 additions and 17 deletions
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43
sys/arch/i386/i386/locore.s
View File

@ -1,4 +1,4 @@
/* $NetBSD: locore.s,v 1.102 1994/12/10 00:28:18 mycroft Exp $ */
/* $NetBSD: locore.s,v 1.103 1995/01/15 00:52:21 mycroft Exp $ */
#undef DIAGNOSTIC
#define DIAGNOSTIC
@ -599,12 +599,13 @@ reloc_gdt:
#if defined(I486_CPU) || defined(I586_CPU)
/*
* Now we've run main() and determined what CPU type we are, so we can
* enable WP mode on i486 CPUs and above.
* enable ring 0 write protection and outer ring alignment checking on
* i486 CPUs and above.
*/
cmpl $CPUCLASS_386,_cpu_class
je 1f # 386s can't handle WP mode
movl %cr0,%eax # get control word
orl $CR0_WP,%eax # enable ring 0 Write Protection
je 1f
movl %cr0,%eax
orl $CR0_WP|CR0_AM,%eax
movl %eax,%cr0
1:
#endif
@ -1943,14 +1944,13 @@ calltrap:
movl _cpl,%ebx
#endif /* DIAGNOSTIC */
call _trap
2: /*
* Check for ASTs.
*/
2: /* Check for ASTs on exit to user mode. */
cli
cmpb $0,_astpending
je 1f
testb $SEL_RPL_MASK,TF_CS(%esp)
jz 1f
btrl $0,_astpending
jnc 1f
movb $0,_astpending
sti
movl $T_ASTFLT,TF_TRAPNO(%esp)
call _trap
@ -1992,9 +1992,9 @@ IDTVEC(osyscall)
/* Set eflags in trap frame. */
pushfl
popl 8(%esp)
/* Turn off trace bit. */
/* Turn off trace flag and nested task. */
pushfl
andb $~(PSL_T>>8),1(%esp)
andb $~((PSL_T|PSL_NT)>>8),1(%esp)
popfl
pushl $7 # size of instruction for restart
jmp syscall1
@ -2011,14 +2011,14 @@ syscall1:
movl _cpl,%ebx
#endif /* DIAGNOSTIC */
call _syscall
2: /*
* Check for ASTs.
*/
2: /* Check for ASTs on exit to user mode. */
cli
cmpb $0,_astpending
je 1f
/* Always returning to user mode here. */
btrl $0,_astpending
jnc 1f
movb $0,_astpending
sti
/* Pushed T_ASTFLT into tf_trapno on entry. */
call _trap
#ifndef DIAGNOSTIC
1: INTRFASTEXIT
@ -2038,6 +2038,15 @@ syscall1:
4: .asciz "WARNING: SPL NOT LOWERED ON SYSCALL EXIT\n"
#endif /* DIAGNOSTIC */
ENTRY(resume_iret)
ZTRAP(T_PROTFLT)
ENTRY(resume_pop_ds)
movl $KDSEL,%eax
movl %ax,%es
ENTRY(resume_pop_es)
movl $T_PROTFLT,TF_TRAPNO(%esp)
jmp calltrap
#include <i386/isa/vector.s>
#include <i386/isa/icu.s>