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mycroft 1995-01-15 01:15:04 +00:00
parent ecef8fddfa
commit 98fc96ea40
1 changed files with 16 additions and 2 deletions
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18
sys/arch/i386/i386/trap.c
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@ -1,4 +1,4 @@
/* $NetBSD: trap.c,v 1.65 1995/01/15 00:55:25 mycroft Exp $ */
/* $NetBSD: trap.c,v 1.66 1995/01/15 01:15:04 mycroft Exp $ */
#undef DEBUG
#define DEBUG
@ -214,7 +214,21 @@ trap(frame)
return;
}
/* Check for failure during return to user mode. */
/*
* Check for failure during return to user mode.
*
* We do this by looking at the instruction we faulted on. The
* specific instructions we recognize only happen when
* returning from a trap, syscall, or interrupt.
*
* XXX
* The heuristic used here will currently fail for the case of
* one of the 2 pop instructions faulting when returning from a
* a fast interrupt. This should not be possible. It can be
* fixed by rearranging the trap frame so that the stack format
* at this point is the same as on exit from a `slow'
* interrupt.
*/
switch (*(u_char *)frame.tf_eip) {
case 0xcf: /* iret */
vframe = (void *)(frame.tf_esp - 44);