minix/kernel/arch/i386/exception.c
2010-02-14 18:39:47 +00:00

264 lines
7.6 KiB
C

/* This file contains a simple exception handler. Exceptions in user
* processes are converted to signals. Exceptions in a kernel task cause
* a panic.
*/
#include "../../kernel.h"
#include "proto.h"
#include <signal.h>
#include <string.h>
#include "../../proc.h"
#include "../../proto.h"
extern int vm_copy_in_progress, catch_pagefaults;
extern struct proc *vm_copy_from, *vm_copy_to;
void pagefault( struct proc *pr,
struct exception_frame * frame,
int is_nested)
{
int in_physcopy = 0;
reg_t pagefaultcr2;
vmassert(frame);
pagefaultcr2 = read_cr2();
#if 0
printf("kernel: pagefault in pr %d, addr 0x%lx, his cr3 0x%lx, actual cr3 0x%lx\n",
pr->p_endpoint, pagefaultcr2, pr->p_seg.p_cr3, read_cr3());
#endif
if(pr->p_seg.p_cr3) {
vmassert(pr->p_seg.p_cr3 == read_cr3());
}
in_physcopy = (frame->eip > (vir_bytes) phys_copy) &&
(frame->eip < (vir_bytes) phys_copy_fault);
if((is_nested || iskernelp(pr)) &&
catch_pagefaults && in_physcopy) {
#if 0
printf("pf caught! addr 0x%lx\n", pagefaultcr2);
#endif
if (is_nested) {
frame->eip = (reg_t) phys_copy_fault_in_kernel;
}
else {
pr->p_reg.pc = (reg_t) phys_copy_fault;
pr->p_reg.retreg = pagefaultcr2;
}
return;
}
/* System processes that don't have their own page table can't
* have page faults. VM does have its own page table but also
* can't have page faults (because VM has to handle them).
*/
if(is_nested || (pr->p_endpoint <= INIT_PROC_NR &&
!(pr->p_misc_flags & MF_FULLVM)) || pr->p_endpoint == VM_PROC_NR) {
/* Page fault we can't / don't want to
* handle.
*/
kprintf("pagefault for process %d ('%s'), pc = 0x%x, addr = 0x%x, flags = 0x%x, is_nested %d\n",
pr->p_endpoint, pr->p_name, pr->p_reg.pc,
pagefaultcr2, frame->errcode, is_nested);
proc_stacktrace(pr);
if(pr->p_endpoint != SYSTEM) {
proc_stacktrace(proc_addr(SYSTEM));
}
kprintf("pc of pagefault: 0x%lx\n", frame->eip);
minix_panic("page fault in system process", pr->p_endpoint);
return;
}
/* Don't schedule this process until pagefault is handled. */
vmassert(pr->p_seg.p_cr3 == read_cr3());
vmassert(!RTS_ISSET(pr, RTS_PAGEFAULT));
RTS_SET(pr, RTS_PAGEFAULT);
/* Save pagefault details, suspend process,
* add process to pagefault chain,
* and tell VM there is a pagefault to be
* handled.
*/
pr->p_pagefault.pf_virtual = pagefaultcr2;
pr->p_pagefault.pf_flags = frame->errcode;
pr->p_nextpagefault = pagefaults;
pagefaults = pr;
mini_notify(proc_addr(HARDWARE), VM_PROC_NR);
return;
}
/*===========================================================================*
* exception *
*===========================================================================*/
PUBLIC void exception_handler(int is_nested, struct exception_frame * frame)
{
/* 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 },
{ "Coprocessor 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 },
{ "Alignment check", SIGBUS, 386 },
{ "Machine check", SIGBUS, 386 },
{ "SIMD exception", SIGFPE, 386 },
};
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[frame->vector];
if (frame->vector == 2) { /* spurious NMI on some machines */
kprintf("got spurious NMI\n");
return;
}
/*
* handle special cases for nested problems as they might be tricky or filter
* them out quickly if the traps are not nested
*/
if (is_nested) {
/*
* if a problem occured while copying a message from userspace because
* of a wrong pointer supplied by userland, handle it the only way we
* can handle it ...
*/
if (((void*)frame->eip >= (void*)copy_msg_to_user &&
(void*)frame->eip <= (void*)__copy_msg_to_user_end) ||
((void*)frame->eip >= (void*)copy_msg_from_user &&
(void*)frame->eip <= (void*)__copy_msg_from_user_end)) {
switch(frame->vector) {
/* these error are expected */
case PAGE_FAULT_VECTOR:
case PROTECTION_VECTOR:
frame->eip = (reg_t) __user_copy_msg_pointer_failure;
return;
default:
minix_panic("Copy involving a user pointer "
"failed unexpectedly!", NO_NUM);
}
}
}
if(frame->vector == PAGE_FAULT_VECTOR) {
pagefault(saved_proc, frame, is_nested);
return;
}
/* If an exception occurs while running a process, the is_nested variable
* will be zero. Exceptions in interrupt handlers or system traps will make
* is_nested non-zero.
*/
if (is_nested == 0 && ! iskernelp(saved_proc)) {
#if 0
{
kprintf(
"vec_nr= %d, trap_errno= 0x%lx, eip= 0x%lx, cs= 0x%x, eflags= 0x%lx\n",
frame->vector, (unsigned long)frame->errcode,
(unsigned long)frame->eip, frame->cs,
(unsigned long)frame->eflags);
printseg("cs: ", 1, saved_proc, frame->cs);
printseg("ds: ", 0, saved_proc, saved_proc->p_reg.ds);
if(saved_proc->p_reg.ds != saved_proc->p_reg.ss) {
printseg("ss: ", 0, saved_proc, saved_proc->p_reg.ss);
}
proc_stacktrace(saved_proc);
}
#endif
cause_sig(proc_nr(saved_proc), ep->signum);
return;
}
/* Exception in system code. This is not supposed to happen. */
if (ep->msg == NIL_PTR || machine.processor < ep->minprocessor)
kprintf("\nIntel-reserved exception %d\n", frame->vector);
else
kprintf("\n%s\n", ep->msg);
kprintf("is_nested = %d ", is_nested);
kprintf("vec_nr= %d, trap_errno= 0x%x, eip= 0x%x, cs= 0x%x, eflags= 0x%x trap_esp 0x%08x\n",
frame->vector, frame->errcode, frame->eip, frame->cs, frame->eflags, frame);
/* TODO should we enable this only when compiled for some debug mode? */
if (saved_proc) {
kprintf("scheduled was: process %d (%s), ", proc_nr(saved_proc), saved_proc->p_name);
kprintf("pc = %u:0x%x\n", (unsigned) saved_proc->p_reg.cs,
(unsigned) saved_proc->p_reg.pc);
proc_stacktrace(saved_proc);
minix_panic("exception in a kernel task", saved_proc->p_endpoint);
}
else {
/* in an early stage of boot process we don't have processes yet */
minix_panic("exception in kernel while booting", NO_NUM);
}
}
/*===========================================================================*
* stacktrace *
*===========================================================================*/
PUBLIC void proc_stacktrace(struct proc *whichproc)
{
reg_t v_bp, v_pc, v_hbp;
int iskernel;
v_bp = whichproc->p_reg.fp;
iskernel = iskernelp(whichproc);
kprintf("%-8.8s %6d 0x%lx ",
whichproc->p_name, whichproc->p_endpoint, whichproc->p_reg.pc);
while(v_bp) {
#define PRCOPY(pr, pv, v, n) \
(iskernel ? (memcpy((char *) v, (char *) pv, n), OK) : \
data_copy(pr->p_endpoint, pv, KERNEL, (vir_bytes) (v), n))
if(PRCOPY(whichproc, v_bp, &v_hbp, sizeof(v_hbp)) != OK) {
kprintf("(v_bp 0x%lx ?)", v_bp);
break;
}
if(PRCOPY(whichproc, v_bp + sizeof(v_pc), &v_pc, sizeof(v_pc)) != OK) {
kprintf("(v_pc 0x%lx ?)", v_bp + sizeof(v_pc));
break;
}
kprintf("0x%lx ", (unsigned long) v_pc);
if(v_hbp != 0 && v_hbp <= v_bp) {
kprintf("(hbp %lx ?)", v_hbp);
break;
}
v_bp = v_hbp;
}
kprintf("\n");
}