237 lines
6.6 KiB
C
Executable File
237 lines
6.6 KiB
C
Executable File
/* This file contains a simple exception handler. Exceptions in user
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* processes are converted to signals. Exceptions in a kernel task cause
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* a panic.
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*/
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#include "../../kernel.h"
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#include "proto.h"
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#include <signal.h>
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#include <stdio.h>
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#include <string.h>
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#include <minix/sysutil.h>
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#include "../../proc.h"
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#include "../../proto.h"
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extern int vm_copy_in_progress, catch_pagefaults;
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extern struct proc *vm_copy_from, *vm_copy_to;
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u32_t pagefault_cr2, pagefault_count = 0;
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vir_bytes *old_eip_ptr = NULL, *old_eax_ptr = NULL;
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void pagefault(vir_bytes old_eip, struct proc *pr, int trap_errno)
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{
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int s;
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vir_bytes ph;
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u32_t pte;
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int procok = 0, pcok = 0, rangeok = 0;
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int in_memcpy = 0, in_physcopy = 0;
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vmassert(old_eip_ptr);
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vmassert(old_eax_ptr);
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vmassert(*old_eip_ptr == old_eip);
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vmassert(old_eip_ptr != &old_eip);
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vmassert(pagefault_count == 1);
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if(catch_pagefaults) {
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vir_bytes test_eip;
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test_eip = k_reenter ? old_eip : pr->p_reg.pc;
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in_memcpy = (test_eip > (vir_bytes) _memcpy_k) &&
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(test_eip < (vir_bytes) _memcpy_k_fault);
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in_physcopy = (test_eip > (vir_bytes) phys_copy) &&
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(test_eip < (vir_bytes) phys_copy_fault);
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if((pcok = in_memcpy || in_physcopy)) {
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pagefault_count = 0;
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if(in_memcpy) {
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vmassert(!in_physcopy);
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*old_eip_ptr = _memcpy_k_fault;
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}
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if(in_physcopy) {
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vmassert(!in_memcpy);
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*old_eip_ptr = phys_copy_fault;
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}
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*old_eax_ptr = pagefault_cr2;
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return;
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}
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}
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/* System processes that don't have their own page table can't
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* have page faults. VM does have its own page table but also
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* can't have page faults (because VM has to handle them).
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*/
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if(k_reenter || (pr->p_endpoint <= INIT_PROC_NR &&
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!(pr->p_misc_flags & MF_FULLVM)) || pr->p_endpoint == VM_PROC_NR) {
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/* Page fault we can't / don't want to
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* handle.
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*/
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kprintf("pagefault for process %d ('%s'), pc = 0x%x, addr = 0x%x, flags = 0x%x\n",
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pr->p_endpoint, pr->p_name, pr->p_reg.pc,
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pagefault_cr2, trap_errno);
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proc_stacktrace(pr);
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minix_panic("page fault in system process", pr->p_endpoint);
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return;
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}
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/* Don't schedule this process until pagefault is handled. */
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vmassert(pr->p_seg.p_cr3 == read_cr3());
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vmassert(!RTS_ISSET(pr, PAGEFAULT));
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RTS_LOCK_SET(pr, PAGEFAULT);
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/* Save pagefault details, suspend process,
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* add process to pagefault chain,
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* and tell VM there is a pagefault to be
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* handled.
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*/
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pr->p_pagefault.pf_virtual = pagefault_cr2;
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pr->p_pagefault.pf_flags = trap_errno;
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pr->p_nextpagefault = pagefaults;
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pagefaults = pr;
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lock_notify(SYSTEM, VM_PROC_NR);
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pagefault_count = 0;
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return;
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}
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/*===========================================================================*
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* exception *
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*===========================================================================*/
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PUBLIC void exception(vec_nr, trap_errno, old_eip, old_cs, old_eflags)
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unsigned vec_nr;
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u32_t trap_errno;
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u32_t old_eip;
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U16_t old_cs;
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u32_t old_eflags;
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{
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/* An exception or unexpected interrupt has occurred. */
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struct proc *t;
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struct ex_s {
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char *msg;
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int signum;
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int minprocessor;
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};
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static struct ex_s ex_data[] = {
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{ "Divide error", SIGFPE, 86 },
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{ "Debug exception", SIGTRAP, 86 },
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{ "Nonmaskable interrupt", SIGBUS, 86 },
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{ "Breakpoint", SIGEMT, 86 },
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{ "Overflow", SIGFPE, 86 },
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{ "Bounds check", SIGFPE, 186 },
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{ "Invalid opcode", SIGILL, 186 },
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{ "Coprocessor not available", SIGFPE, 186 },
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{ "Double fault", SIGBUS, 286 },
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{ "Copressor segment overrun", SIGSEGV, 286 },
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{ "Invalid TSS", SIGSEGV, 286 },
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{ "Segment not present", SIGSEGV, 286 },
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{ "Stack exception", SIGSEGV, 286 }, /* STACK_FAULT already used */
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{ "General protection", SIGSEGV, 286 },
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{ "Page fault", SIGSEGV, 386 }, /* not close */
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{ NIL_PTR, SIGILL, 0 }, /* probably software trap */
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{ "Coprocessor error", SIGFPE, 386 },
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};
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register struct ex_s *ep;
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struct proc *saved_proc;
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/* Save proc_ptr, because it may be changed by debug statements. */
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saved_proc = proc_ptr;
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ep = &ex_data[vec_nr];
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if (vec_nr == 2) { /* spurious NMI on some machines */
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kprintf("got spurious NMI\n");
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return;
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}
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if(vec_nr == PAGE_FAULT_VECTOR) {
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pagefault(old_eip, saved_proc, trap_errno);
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return;
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}
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/* If an exception occurs while running a process, the k_reenter variable
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* will be zero. Exceptions in interrupt handlers or system traps will make
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* k_reenter larger than zero.
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*/
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if (k_reenter == 0 && ! iskernelp(saved_proc)) {
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{
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kprintf(
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"exception for process %d, endpoint %d ('%s'), pc = 0x%x:0x%x, sp = 0x%x:0x%x\n",
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proc_nr(saved_proc), saved_proc->p_endpoint,
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saved_proc->p_name,
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saved_proc->p_reg.cs, saved_proc->p_reg.pc,
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saved_proc->p_reg.ss, saved_proc->p_reg.sp);
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kprintf(
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"vec_nr= %d, trap_errno= 0x%lx, eip= 0x%lx, cs= 0x%x, eflags= 0x%lx\n",
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vec_nr, (unsigned long)trap_errno,
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(unsigned long)old_eip, old_cs,
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(unsigned long)old_eflags);
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proc_stacktrace(saved_proc);
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}
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kprintf("kernel: cause_sig %d for %d\n",
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ep->signum, saved_proc->p_endpoint);
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cause_sig(proc_nr(saved_proc), ep->signum);
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return;
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}
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/* 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);
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else
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kprintf("\n%s\n", ep->msg);
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kprintf("k_reenter = %d ", k_reenter);
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kprintf("process %d (%s), ", proc_nr(saved_proc), saved_proc->p_name);
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kprintf("pc = %u:0x%x\n", (unsigned) saved_proc->p_reg.cs,
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(unsigned) saved_proc->p_reg.pc);
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kprintf(
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"vec_nr= %d, trap_errno= 0x%lx, eip= 0x%lx, cs= 0x%x, eflags= 0x%lx\n",
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vec_nr, (unsigned long)trap_errno,
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(unsigned long)old_eip, old_cs, (unsigned long)old_eflags);
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proc_stacktrace(saved_proc);
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minix_panic("exception in a kernel task", saved_proc->p_endpoint);
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}
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/*===========================================================================*
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* stacktrace *
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*===========================================================================*/
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PUBLIC void proc_stacktrace(struct proc *proc)
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{
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reg_t bp, v_bp, v_pc, v_hbp;
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v_bp = proc->p_reg.fp;
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kprintf("%-8.8s %6d 0x%lx ",
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proc->p_name, proc->p_endpoint, proc->p_reg.pc);
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while(v_bp) {
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#define PRCOPY(pr, pv, v, n) \
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(iskernelp(pr) ? (memcpy((char *) v, (char *) pv, n), OK) : \
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data_copy(pr->p_endpoint, pv, SYSTEM, (vir_bytes) (v), n))
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if(PRCOPY(proc, v_bp, &v_hbp, sizeof(v_hbp)) != OK) {
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kprintf("(v_bp 0x%lx ?)", v_bp);
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break;
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}
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if(PRCOPY(proc, v_bp + sizeof(v_pc), &v_pc, sizeof(v_pc)) != OK) {
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kprintf("(v_pc 0x%lx ?)", v_pc);
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break;
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}
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kprintf("0x%lx ", (unsigned long) v_pc);
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if(v_hbp != 0 && v_hbp <= v_bp) {
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kprintf("(hbp %lx ?)", v_hbp);
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break;
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}
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v_bp = v_hbp;
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}
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kprintf("\n");
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}
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