minix/kernel/exception.c

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/* This file contains a simple exception handler. Exceptions in user
* processes are converted to signals. Exceptions in a kernel task cause
* a panic.
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*/
#include "kernel.h"
#include <signal.h>
#include "proc.h"
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/*===========================================================================*
* exception *
*===========================================================================*/
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PUBLIC void exception(vec_nr)
unsigned vec_nr;
{
/* An exception or unexpected interrupt has occurred. */
struct ex_s {
char *msg;
int signum;
int minprocessor;
};
static struct ex_s ex_data[] = {
{ "Divide error", SIGFPE, 86 },
{ "Debug exception", SIGTRAP, 86 },
{ "Nonmaskable interrupt", SIGBUS, 86 },
{ "Breakpoint", SIGEMT, 86 },
{ "Overflow", SIGFPE, 86 },
{ "Bounds check", SIGFPE, 186 },
{ "Invalid opcode", SIGILL, 186 },
{ "Coprocessor not available", SIGFPE, 186 },
{ "Double fault", SIGBUS, 286 },
{ "Copressor segment overrun", SIGSEGV, 286 },
{ "Invalid TSS", SIGSEGV, 286 },
{ "Segment not present", SIGSEGV, 286 },
{ "Stack exception", SIGSEGV, 286 }, /* STACK_FAULT already used */
{ "General protection", SIGSEGV, 286 },
{ "Page fault", SIGSEGV, 386 }, /* not close */
{ NIL_PTR, SIGILL, 0 }, /* probably software trap */
{ "Coprocessor error", SIGFPE, 386 },
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};
register struct ex_s *ep;
struct proc *saved_proc;
/* Save proc_ptr, because it may be changed by debug statements. */
saved_proc = proc_ptr;
ep = &ex_data[vec_nr];
if (vec_nr == 2) { /* spurious NMI on some machines */
kprintf("got spurious NMI\n");
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return;
}
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/* If an exception occurs while running a process, the k_reenter variable
* will be zero. Exceptions in interrupt handlers or system traps will make
* k_reenter larger than zero.
*/
if (k_reenter == 0 && ! iskernelp(saved_proc)) {
#if 0
{
kprintf(
"exception for process %d, pc = 0x%x:0x%x, sp = 0x%x:0x%x\n",
proc_nr(saved_proc),
saved_proc->p_reg.cs, saved_proc->p_reg.pc,
saved_proc->p_reg.ss, saved_proc->p_reg.sp);
kprintf("edi = 0x%x\n", saved_proc->p_reg.di);
#if DEBUG_STACKTRACE
stacktrace(saved_proc);
#endif
}
#endif
cause_sig(proc_nr(saved_proc), ep->signum);
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return;
}
/* Exception in system code. This is not supposed to happen. */
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if (ep->msg == NIL_PTR || machine.processor < ep->minprocessor)
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kprintf("\nIntel-reserved exception %d\n", vec_nr);
else
kprintf("\n%s\n", ep->msg);
kprintf("k_reenter = %d ", k_reenter);
kprintf("process %d (%s), ", proc_nr(saved_proc), saved_proc->p_name);
kprintf("pc = %u:0x%x", (unsigned) saved_proc->p_reg.cs,
(unsigned) saved_proc->p_reg.pc);
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panic("exception in a kernel task", NO_NUM);
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}
#if DEBUG_STACKTRACE
/*===========================================================================*
* stacktrace *
*===========================================================================*/
PUBLIC void stacktrace(proc)
struct proc *proc;
{
reg_t bp, v_bp, v_pc, v_hbp;
v_bp = proc->p_reg.fp;
kprintf("stacktrace: ");
while(v_bp) {
phys_bytes p;
if(!(p = umap_local(proc, D, v_bp, sizeof(v_bp)))) {
kprintf("(bad bp %lx)", v_bp);
break;
}
phys_copy(p+sizeof(v_pc), vir2phys(&v_pc), sizeof(v_pc));
phys_copy(p, vir2phys(&v_hbp), sizeof(v_hbp));
kprintf("0x%lx ", (unsigned long) v_pc);
if(v_hbp != 0 && v_hbp <= v_bp) {
kprintf("(bad hbp %lx)", v_hbp);
break;
}
v_bp = v_hbp;
}
kprintf("\n");
}
#endif