. fold 2 exception-in-kernel cases (pagefault and rest) into 1 . for exceptions that occur in kernel, don't just print kernel stacktrace (typically that is just the exception handler) but also the stacktrace of when the exception happened
319 lines
8.9 KiB
C
319 lines
8.9 KiB
C
/* 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/kernel.h"
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#include "arch_proto.h"
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#include <signal.h>
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#include <string.h>
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#include <assert.h>
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#include "kernel/proc.h"
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#include "kernel/proto.h"
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#include <machine/vm.h>
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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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{ "Coprocessor 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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{ NULL, SIGILL, 0 }, /* probably software trap */
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{ "Coprocessor error", SIGFPE, 386 },
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{ "Alignment check", SIGBUS, 386 },
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{ "Machine check", SIGBUS, 386 },
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{ "SIMD exception", SIGFPE, 386 },
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};
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extern int catch_pagefaults;
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PRIVATE void proc_stacktrace_execute(struct proc *whichproc, reg_t v_bp, reg_t pc);
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PRIVATE void pagefault( struct proc *pr,
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struct exception_frame * frame,
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int is_nested)
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{
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int in_physcopy = 0;
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reg_t pagefaultcr2;
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message m_pagefault;
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int err;
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pagefaultcr2 = read_cr2();
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#if 0
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printf("kernel: pagefault in pr %d, addr 0x%lx, his cr3 0x%lx, actual cr3 0x%lx\n",
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pr->p_endpoint, pagefaultcr2, pr->p_seg.p_cr3, read_cr3());
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#endif
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in_physcopy = (frame->eip > (vir_bytes) phys_copy) &&
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(frame->eip < (vir_bytes) phys_copy_fault);
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if((is_nested || iskernelp(pr)) &&
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catch_pagefaults && in_physcopy) {
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#if 0
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printf("pf caught! addr 0x%lx\n", pagefaultcr2);
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#endif
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if (is_nested) {
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frame->eip = (reg_t) phys_copy_fault_in_kernel;
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}
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else {
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pr->p_reg.pc = (reg_t) phys_copy_fault;
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pr->p_reg.retreg = pagefaultcr2;
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}
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return;
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}
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if(is_nested) {
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printf("pagefault in kernel at pc 0x%lx address 0x%lx\n",
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frame->eip, pagefaultcr2);
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inkernel_disaster(pr, frame, NULL, is_nested);
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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((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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printf("pagefault for process %d ('%s') on CPU %d, "
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"pc = 0x%x, addr = 0x%x, flags = 0x%x, is_nested %d\n",
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pr->p_endpoint, pr->p_name, cpuid, pr->p_reg.pc,
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pagefaultcr2, frame->errcode, is_nested);
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proc_stacktrace(pr);
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printf("pc of pagefault: 0x%lx\n", frame->eip);
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cause_sig(proc_nr(pr), SIGSEGV);
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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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RTS_SET(pr, RTS_PAGEFAULT);
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/* tell Vm about the pagefault */
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m_pagefault.m_source = pr->p_endpoint;
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m_pagefault.m_type = VM_PAGEFAULT;
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m_pagefault.VPF_ADDR = pagefaultcr2;
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m_pagefault.VPF_FLAGS = frame->errcode;
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if ((err = mini_send(pr, VM_PROC_NR,
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&m_pagefault, FROM_KERNEL))) {
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panic("WARNING: pagefault: mini_send returned %d\n", err);
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}
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return;
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}
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PRIVATE void inkernel_disaster(struct proc *saved_proc,
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struct exception_frame * frame, struct ex_s *ep,
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int is_nested)
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{
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if(ep) {
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if (ep->msg == NULL || machine.processor < ep->minprocessor)
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printf("\nIntel-reserved exception %d\n", frame->vector);
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else
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printf("\n%s\n", ep->msg);
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}
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printf("cpu %d is_nested = %d ", cpuid, is_nested);
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printf("vec_nr= %d, trap_errno= 0x%x, eip= 0x%x, "
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"cs= 0x%x, eflags= 0x%x trap_esp 0x%08x\n",
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frame->vector, frame->errcode, frame->eip,
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frame->cs, frame->eflags, frame);
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printf("KERNEL registers :\n");
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#define REG(n) (((u32_t *)frame)[-n])
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printf(
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"\t%%eax 0x%08x %%ebx 0x%08x %%ecx 0x%08x %%edx 0x%08x\n"
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"\t%%esp 0x%08x %%ebp 0x%08x %%esi 0x%08x %%edi 0x%08x\n",
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REG(1), REG(2), REG(3), REG(4),
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REG(5), REG(6), REG(7), REG(8));
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{
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reg_t k_ebp = REG(6);
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printf("KERNEL stacktrace, starting with ebp = 0x%lx:\n", k_ebp);
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proc_stacktrace_execute(proc_addr(SYSTEM), k_ebp, frame->eip);
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}
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printseg("ker cs: ", 1, NULL, frame->cs);
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printseg("ker ds: ", 0, NULL, DS_SELECTOR);
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if (saved_proc) {
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printf("scheduled was: process %d (%s), ", saved_proc->p_endpoint, saved_proc->p_name);
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printf("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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proc_stacktrace(saved_proc);
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panic("Unhandled kernel exception");
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}
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/* in an early stage of boot process we don't have processes yet */
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panic("exception in kernel while booting, no saved_proc yet");
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}
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/*===========================================================================*
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* exception *
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*===========================================================================*/
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PUBLIC void exception_handler(int is_nested, struct exception_frame * frame)
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{
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/* An exception or unexpected interrupt has occurred. */
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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 = get_cpulocal_var(proc_ptr);
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ep = &ex_data[frame->vector];
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if (frame->vector == 2) { /* spurious NMI on some machines */
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printf("got spurious NMI\n");
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return;
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}
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/*
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* handle special cases for nested problems as they might be tricky or filter
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* them out quickly if the traps are not nested
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*/
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if (is_nested) {
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/*
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* if a problem occured while copying a message from userspace because
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* of a wrong pointer supplied by userland, handle it the only way we
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* can handle it ...
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*/
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if (((void*)frame->eip >= (void*)copy_msg_to_user &&
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(void*)frame->eip <= (void*)__copy_msg_to_user_end) ||
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((void*)frame->eip >= (void*)copy_msg_from_user &&
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(void*)frame->eip <= (void*)__copy_msg_from_user_end)) {
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switch(frame->vector) {
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/* these error are expected */
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case PAGE_FAULT_VECTOR:
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case PROTECTION_VECTOR:
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frame->eip = (reg_t) __user_copy_msg_pointer_failure;
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return;
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default:
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panic("Copy involving a user pointer failed unexpectedly!");
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}
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}
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}
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if(frame->vector == PAGE_FAULT_VECTOR) {
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pagefault(saved_proc, frame, is_nested);
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return;
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}
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/* If an exception occurs while running a process, the is_nested variable
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* will be zero. Exceptions in interrupt handlers or system traps will make
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* is_nested non-zero.
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*/
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if (is_nested == 0 && ! iskernelp(saved_proc)) {
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#if 0
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{
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printf(
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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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frame->vector, (unsigned long)frame->errcode,
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(unsigned long)frame->eip, frame->cs,
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(unsigned long)frame->eflags);
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printseg("cs: ", 1, saved_proc, frame->cs);
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printseg("ds: ", 0, saved_proc, saved_proc->p_reg.ds);
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if(saved_proc->p_reg.ds != saved_proc->p_reg.ss) {
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printseg("ss: ", 0, saved_proc, saved_proc->p_reg.ss);
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}
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proc_stacktrace(saved_proc);
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}
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#endif
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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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inkernel_disaster(saved_proc, frame, ep, is_nested);
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panic("return from inkernel_disaster");
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}
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/*===========================================================================*
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* proc_stacktrace_execute *
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*===========================================================================*/
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PRIVATE void proc_stacktrace_execute(struct proc *whichproc, reg_t v_bp, reg_t pc)
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{
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reg_t v_hbp;
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int iskernel;
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int n = 0;
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iskernel = iskernelp(whichproc);
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printf("%-8.8s %6d 0x%lx ",
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whichproc->p_name, whichproc->p_endpoint, pc);
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while(v_bp) {
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reg_t v_pc;
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#define PRCOPY(pr, pv, v, n) \
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(iskernel ? (memcpy((char *) v, (char *) pv, n), OK) : \
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data_copy(pr->p_endpoint, pv, KERNEL, (vir_bytes) (v), n))
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if(PRCOPY(whichproc, v_bp, &v_hbp, sizeof(v_hbp)) != OK) {
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printf("(v_bp 0x%lx ?)", v_bp);
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break;
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}
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if(PRCOPY(whichproc, v_bp + sizeof(v_pc), &v_pc, sizeof(v_pc)) != OK) {
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printf("(v_pc 0x%lx ?)", v_bp + sizeof(v_pc));
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break;
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}
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printf("0x%lx ", (unsigned long) v_pc);
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if(v_hbp != 0 && v_hbp <= v_bp) {
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printf("(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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if(n++ > 50) {
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printf("(truncated after %d steps) ", n);
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break;
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}
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}
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printf("\n");
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}
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/*===========================================================================*
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* proc_stacktrace *
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*===========================================================================*/
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PUBLIC void proc_stacktrace(struct proc *whichproc)
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{
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proc_stacktrace_execute(whichproc, whichproc->p_reg.fp, whichproc->p_reg.pc);
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}
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PUBLIC void enable_fpu_exception(void)
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{
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u32_t cr0 = read_cr0();
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if(!(cr0 & I386_CR0_TS))
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write_cr0(cr0 | I386_CR0_TS);
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}
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PUBLIC void disable_fpu_exception(void)
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{
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clts();
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}
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