962 строки
24 KiB
C
962 строки
24 KiB
C
/*
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* Copyright (C) 1995 Linus Torvalds
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* Copyright (C) 2001,2002 Andi Kleen, SuSE Labs.
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*/
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#include <linux/signal.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include <linux/ptrace.h>
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#include <linux/mmiotrace.h>
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#include <linux/mman.h>
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#include <linux/mm.h>
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#include <linux/smp.h>
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#include <linux/interrupt.h>
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#include <linux/init.h>
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#include <linux/tty.h>
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#include <linux/vt_kern.h> /* For unblank_screen() */
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#include <linux/compiler.h>
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#include <linux/highmem.h>
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#include <linux/bootmem.h> /* for max_low_pfn */
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#include <linux/vmalloc.h>
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#include <linux/module.h>
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#include <linux/kprobes.h>
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#include <linux/uaccess.h>
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#include <linux/kdebug.h>
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#include <asm/system.h>
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#include <asm/desc.h>
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#include <asm/segment.h>
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#include <asm/pgalloc.h>
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#include <asm/smp.h>
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#include <asm/tlbflush.h>
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#include <asm/proto.h>
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#include <asm-generic/sections.h>
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/*
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* Page fault error code bits
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* bit 0 == 0 means no page found, 1 means protection fault
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* bit 1 == 0 means read, 1 means write
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* bit 2 == 0 means kernel, 1 means user-mode
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* bit 3 == 1 means use of reserved bit detected
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* bit 4 == 1 means fault was an instruction fetch
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*/
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#define PF_PROT (1<<0)
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#define PF_WRITE (1<<1)
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#define PF_USER (1<<2)
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#define PF_RSVD (1<<3)
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#define PF_INSTR (1<<4)
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static inline int kmmio_fault(struct pt_regs *regs, unsigned long addr)
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{
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#ifdef CONFIG_MMIOTRACE_HOOKS
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if (unlikely(is_kmmio_active()))
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if (kmmio_handler(regs, addr) == 1)
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return -1;
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#endif
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return 0;
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}
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static inline int notify_page_fault(struct pt_regs *regs)
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{
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#ifdef CONFIG_KPROBES
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int ret = 0;
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/* kprobe_running() needs smp_processor_id() */
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if (!user_mode_vm(regs)) {
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preempt_disable();
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if (kprobe_running() && kprobe_fault_handler(regs, 14))
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ret = 1;
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preempt_enable();
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}
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return ret;
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#else
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return 0;
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#endif
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}
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/*
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* X86_32
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* Sometimes AMD Athlon/Opteron CPUs report invalid exceptions on prefetch.
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* Check that here and ignore it.
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*
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* X86_64
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* Sometimes the CPU reports invalid exceptions on prefetch.
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* Check that here and ignore it.
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*
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* Opcode checker based on code by Richard Brunner
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*/
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static int is_prefetch(struct pt_regs *regs, unsigned long addr,
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unsigned long error_code)
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{
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unsigned char *instr;
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int scan_more = 1;
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int prefetch = 0;
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unsigned char *max_instr;
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/*
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* If it was a exec (instruction fetch) fault on NX page, then
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* do not ignore the fault:
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*/
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if (error_code & PF_INSTR)
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return 0;
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instr = (unsigned char *)convert_ip_to_linear(current, regs);
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max_instr = instr + 15;
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if (user_mode(regs) && instr >= (unsigned char *)TASK_SIZE)
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return 0;
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while (scan_more && instr < max_instr) {
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unsigned char opcode;
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unsigned char instr_hi;
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unsigned char instr_lo;
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if (probe_kernel_address(instr, opcode))
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break;
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instr_hi = opcode & 0xf0;
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instr_lo = opcode & 0x0f;
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instr++;
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switch (instr_hi) {
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case 0x20:
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case 0x30:
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/*
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* Values 0x26,0x2E,0x36,0x3E are valid x86 prefixes.
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* In X86_64 long mode, the CPU will signal invalid
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* opcode if some of these prefixes are present so
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* X86_64 will never get here anyway
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*/
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scan_more = ((instr_lo & 7) == 0x6);
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break;
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#ifdef CONFIG_X86_64
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case 0x40:
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/*
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* In AMD64 long mode 0x40..0x4F are valid REX prefixes
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* Need to figure out under what instruction mode the
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* instruction was issued. Could check the LDT for lm,
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* but for now it's good enough to assume that long
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* mode only uses well known segments or kernel.
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*/
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scan_more = (!user_mode(regs)) || (regs->cs == __USER_CS);
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break;
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#endif
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case 0x60:
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/* 0x64 thru 0x67 are valid prefixes in all modes. */
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scan_more = (instr_lo & 0xC) == 0x4;
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break;
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case 0xF0:
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/* 0xF0, 0xF2, 0xF3 are valid prefixes in all modes. */
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scan_more = !instr_lo || (instr_lo>>1) == 1;
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break;
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case 0x00:
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/* Prefetch instruction is 0x0F0D or 0x0F18 */
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scan_more = 0;
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if (probe_kernel_address(instr, opcode))
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break;
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prefetch = (instr_lo == 0xF) &&
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(opcode == 0x0D || opcode == 0x18);
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break;
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default:
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scan_more = 0;
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break;
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}
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}
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return prefetch;
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}
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static void force_sig_info_fault(int si_signo, int si_code,
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unsigned long address, struct task_struct *tsk)
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{
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siginfo_t info;
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info.si_signo = si_signo;
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info.si_errno = 0;
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info.si_code = si_code;
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info.si_addr = (void __user *)address;
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force_sig_info(si_signo, &info, tsk);
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}
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#ifdef CONFIG_X86_64
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static int bad_address(void *p)
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{
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unsigned long dummy;
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return probe_kernel_address((unsigned long *)p, dummy);
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}
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#endif
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static void dump_pagetable(unsigned long address)
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{
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#ifdef CONFIG_X86_32
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__typeof__(pte_val(__pte(0))) page;
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page = read_cr3();
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page = ((__typeof__(page) *) __va(page))[address >> PGDIR_SHIFT];
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#ifdef CONFIG_X86_PAE
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printk("*pdpt = %016Lx ", page);
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if ((page >> PAGE_SHIFT) < max_low_pfn
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&& page & _PAGE_PRESENT) {
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page &= PAGE_MASK;
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page = ((__typeof__(page) *) __va(page))[(address >> PMD_SHIFT)
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& (PTRS_PER_PMD - 1)];
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printk(KERN_CONT "*pde = %016Lx ", page);
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page &= ~_PAGE_NX;
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}
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#else
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printk("*pde = %08lx ", page);
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#endif
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/*
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* We must not directly access the pte in the highpte
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* case if the page table is located in highmem.
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* And let's rather not kmap-atomic the pte, just in case
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* it's allocated already.
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*/
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if ((page >> PAGE_SHIFT) < max_low_pfn
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&& (page & _PAGE_PRESENT)
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&& !(page & _PAGE_PSE)) {
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page &= PAGE_MASK;
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page = ((__typeof__(page) *) __va(page))[(address >> PAGE_SHIFT)
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& (PTRS_PER_PTE - 1)];
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printk("*pte = %0*Lx ", sizeof(page)*2, (u64)page);
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}
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printk("\n");
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#else /* CONFIG_X86_64 */
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pgd_t *pgd;
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pud_t *pud;
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pmd_t *pmd;
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pte_t *pte;
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pgd = (pgd_t *)read_cr3();
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pgd = __va((unsigned long)pgd & PHYSICAL_PAGE_MASK);
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pgd += pgd_index(address);
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if (bad_address(pgd)) goto bad;
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printk("PGD %lx ", pgd_val(*pgd));
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if (!pgd_present(*pgd)) goto ret;
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pud = pud_offset(pgd, address);
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if (bad_address(pud)) goto bad;
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printk("PUD %lx ", pud_val(*pud));
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if (!pud_present(*pud) || pud_large(*pud))
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goto ret;
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pmd = pmd_offset(pud, address);
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if (bad_address(pmd)) goto bad;
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printk("PMD %lx ", pmd_val(*pmd));
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if (!pmd_present(*pmd) || pmd_large(*pmd)) goto ret;
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pte = pte_offset_kernel(pmd, address);
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if (bad_address(pte)) goto bad;
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printk("PTE %lx", pte_val(*pte));
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ret:
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printk("\n");
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return;
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bad:
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printk("BAD\n");
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#endif
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}
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#ifdef CONFIG_X86_32
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static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address)
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{
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unsigned index = pgd_index(address);
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pgd_t *pgd_k;
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pud_t *pud, *pud_k;
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pmd_t *pmd, *pmd_k;
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pgd += index;
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pgd_k = init_mm.pgd + index;
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if (!pgd_present(*pgd_k))
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return NULL;
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/*
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* set_pgd(pgd, *pgd_k); here would be useless on PAE
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* and redundant with the set_pmd() on non-PAE. As would
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* set_pud.
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*/
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pud = pud_offset(pgd, address);
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pud_k = pud_offset(pgd_k, address);
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if (!pud_present(*pud_k))
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return NULL;
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pmd = pmd_offset(pud, address);
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pmd_k = pmd_offset(pud_k, address);
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if (!pmd_present(*pmd_k))
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return NULL;
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if (!pmd_present(*pmd)) {
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set_pmd(pmd, *pmd_k);
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arch_flush_lazy_mmu_mode();
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} else
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BUG_ON(pmd_page(*pmd) != pmd_page(*pmd_k));
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return pmd_k;
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}
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#endif
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#ifdef CONFIG_X86_64
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static const char errata93_warning[] =
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KERN_ERR "******* Your BIOS seems to not contain a fix for K8 errata #93\n"
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KERN_ERR "******* Working around it, but it may cause SEGVs or burn power.\n"
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KERN_ERR "******* Please consider a BIOS update.\n"
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KERN_ERR "******* Disabling USB legacy in the BIOS may also help.\n";
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#endif
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/* Workaround for K8 erratum #93 & buggy BIOS.
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BIOS SMM functions are required to use a specific workaround
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to avoid corruption of the 64bit RIP register on C stepping K8.
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A lot of BIOS that didn't get tested properly miss this.
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The OS sees this as a page fault with the upper 32bits of RIP cleared.
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Try to work around it here.
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Note we only handle faults in kernel here.
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Does nothing for X86_32
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*/
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static int is_errata93(struct pt_regs *regs, unsigned long address)
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{
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#ifdef CONFIG_X86_64
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static int warned;
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if (address != regs->ip)
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return 0;
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if ((address >> 32) != 0)
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return 0;
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address |= 0xffffffffUL << 32;
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if ((address >= (u64)_stext && address <= (u64)_etext) ||
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(address >= MODULES_VADDR && address <= MODULES_END)) {
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if (!warned) {
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printk(errata93_warning);
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warned = 1;
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}
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regs->ip = address;
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return 1;
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}
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#endif
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return 0;
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}
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/*
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* Work around K8 erratum #100 K8 in compat mode occasionally jumps to illegal
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* addresses >4GB. We catch this in the page fault handler because these
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* addresses are not reachable. Just detect this case and return. Any code
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* segment in LDT is compatibility mode.
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*/
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static int is_errata100(struct pt_regs *regs, unsigned long address)
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{
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#ifdef CONFIG_X86_64
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if ((regs->cs == __USER32_CS || (regs->cs & (1<<2))) &&
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(address >> 32))
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return 1;
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#endif
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return 0;
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}
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void do_invalid_op(struct pt_regs *, unsigned long);
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static int is_f00f_bug(struct pt_regs *regs, unsigned long address)
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{
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#ifdef CONFIG_X86_F00F_BUG
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unsigned long nr;
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/*
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* Pentium F0 0F C7 C8 bug workaround.
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*/
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if (boot_cpu_data.f00f_bug) {
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nr = (address - idt_descr.address) >> 3;
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if (nr == 6) {
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do_invalid_op(regs, 0);
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return 1;
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}
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}
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#endif
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return 0;
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}
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static void show_fault_oops(struct pt_regs *regs, unsigned long error_code,
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unsigned long address)
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{
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#ifdef CONFIG_X86_32
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if (!oops_may_print())
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return;
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#endif
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#ifdef CONFIG_X86_PAE
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if (error_code & PF_INSTR) {
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unsigned int level;
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pte_t *pte = lookup_address(address, &level);
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if (pte && pte_present(*pte) && !pte_exec(*pte))
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printk(KERN_CRIT "kernel tried to execute "
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"NX-protected page - exploit attempt? "
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"(uid: %d)\n", current->uid);
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}
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#endif
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printk(KERN_ALERT "BUG: unable to handle kernel ");
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if (address < PAGE_SIZE)
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printk(KERN_CONT "NULL pointer dereference");
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else
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printk(KERN_CONT "paging request");
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printk(KERN_CONT " at %p\n", (void *) address);
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printk(KERN_ALERT "IP:");
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printk_address(regs->ip, 1);
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dump_pagetable(address);
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}
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#ifdef CONFIG_X86_64
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static noinline void pgtable_bad(unsigned long address, struct pt_regs *regs,
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unsigned long error_code)
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{
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unsigned long flags = oops_begin();
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struct task_struct *tsk;
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printk(KERN_ALERT "%s: Corrupted page table at address %lx\n",
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current->comm, address);
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dump_pagetable(address);
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tsk = current;
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tsk->thread.cr2 = address;
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tsk->thread.trap_no = 14;
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tsk->thread.error_code = error_code;
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if (__die("Bad pagetable", regs, error_code))
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regs = NULL;
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oops_end(flags, regs, SIGKILL);
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}
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#endif
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static int spurious_fault_check(unsigned long error_code, pte_t *pte)
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{
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if ((error_code & PF_WRITE) && !pte_write(*pte))
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return 0;
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if ((error_code & PF_INSTR) && !pte_exec(*pte))
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return 0;
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return 1;
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}
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/*
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* Handle a spurious fault caused by a stale TLB entry. This allows
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* us to lazily refresh the TLB when increasing the permissions of a
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* kernel page (RO -> RW or NX -> X). Doing it eagerly is very
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* expensive since that implies doing a full cross-processor TLB
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* flush, even if no stale TLB entries exist on other processors.
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* There are no security implications to leaving a stale TLB when
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* increasing the permissions on a page.
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*/
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static int spurious_fault(unsigned long address,
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unsigned long error_code)
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{
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pgd_t *pgd;
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pud_t *pud;
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pmd_t *pmd;
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pte_t *pte;
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/* Reserved-bit violation or user access to kernel space? */
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if (error_code & (PF_USER | PF_RSVD))
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return 0;
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pgd = init_mm.pgd + pgd_index(address);
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if (!pgd_present(*pgd))
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return 0;
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pud = pud_offset(pgd, address);
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if (!pud_present(*pud))
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return 0;
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if (pud_large(*pud))
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return spurious_fault_check(error_code, (pte_t *) pud);
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pmd = pmd_offset(pud, address);
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if (!pmd_present(*pmd))
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return 0;
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if (pmd_large(*pmd))
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return spurious_fault_check(error_code, (pte_t *) pmd);
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pte = pte_offset_kernel(pmd, address);
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if (!pte_present(*pte))
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return 0;
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return spurious_fault_check(error_code, pte);
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}
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/*
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* X86_32
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* Handle a fault on the vmalloc or module mapping area
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*
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* X86_64
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* Handle a fault on the vmalloc area
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*
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* This assumes no large pages in there.
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*/
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static int vmalloc_fault(unsigned long address)
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{
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#ifdef CONFIG_X86_32
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unsigned long pgd_paddr;
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pmd_t *pmd_k;
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pte_t *pte_k;
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/* Make sure we are in vmalloc area */
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if (!(address >= VMALLOC_START && address < VMALLOC_END))
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return -1;
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/*
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* Synchronize this task's top level page-table
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* with the 'reference' page table.
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*
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* Do _not_ use "current" here. We might be inside
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* an interrupt in the middle of a task switch..
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*/
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pgd_paddr = read_cr3();
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pmd_k = vmalloc_sync_one(__va(pgd_paddr), address);
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if (!pmd_k)
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return -1;
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pte_k = pte_offset_kernel(pmd_k, address);
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if (!pte_present(*pte_k))
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return -1;
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return 0;
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#else
|
|
pgd_t *pgd, *pgd_ref;
|
|
pud_t *pud, *pud_ref;
|
|
pmd_t *pmd, *pmd_ref;
|
|
pte_t *pte, *pte_ref;
|
|
|
|
/* Make sure we are in vmalloc area */
|
|
if (!(address >= VMALLOC_START && address < VMALLOC_END))
|
|
return -1;
|
|
|
|
/* Copy kernel mappings over when needed. This can also
|
|
happen within a race in page table update. In the later
|
|
case just flush. */
|
|
|
|
pgd = pgd_offset(current->mm ?: &init_mm, address);
|
|
pgd_ref = pgd_offset_k(address);
|
|
if (pgd_none(*pgd_ref))
|
|
return -1;
|
|
if (pgd_none(*pgd))
|
|
set_pgd(pgd, *pgd_ref);
|
|
else
|
|
BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref));
|
|
|
|
/* Below here mismatches are bugs because these lower tables
|
|
are shared */
|
|
|
|
pud = pud_offset(pgd, address);
|
|
pud_ref = pud_offset(pgd_ref, address);
|
|
if (pud_none(*pud_ref))
|
|
return -1;
|
|
if (pud_none(*pud) || pud_page_vaddr(*pud) != pud_page_vaddr(*pud_ref))
|
|
BUG();
|
|
pmd = pmd_offset(pud, address);
|
|
pmd_ref = pmd_offset(pud_ref, address);
|
|
if (pmd_none(*pmd_ref))
|
|
return -1;
|
|
if (pmd_none(*pmd) || pmd_page(*pmd) != pmd_page(*pmd_ref))
|
|
BUG();
|
|
pte_ref = pte_offset_kernel(pmd_ref, address);
|
|
if (!pte_present(*pte_ref))
|
|
return -1;
|
|
pte = pte_offset_kernel(pmd, address);
|
|
/* Don't use pte_page here, because the mappings can point
|
|
outside mem_map, and the NUMA hash lookup cannot handle
|
|
that. */
|
|
if (!pte_present(*pte) || pte_pfn(*pte) != pte_pfn(*pte_ref))
|
|
BUG();
|
|
return 0;
|
|
#endif
|
|
}
|
|
|
|
int show_unhandled_signals = 1;
|
|
|
|
/*
|
|
* This routine handles page faults. It determines the address,
|
|
* and the problem, and then passes it off to one of the appropriate
|
|
* routines.
|
|
*/
|
|
#ifdef CONFIG_X86_64
|
|
asmlinkage
|
|
#endif
|
|
void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
|
|
{
|
|
struct task_struct *tsk;
|
|
struct mm_struct *mm;
|
|
struct vm_area_struct *vma;
|
|
unsigned long address;
|
|
int write, si_code;
|
|
int fault;
|
|
#ifdef CONFIG_X86_64
|
|
unsigned long flags;
|
|
#endif
|
|
|
|
/*
|
|
* We can fault from pretty much anywhere, with unknown IRQ state.
|
|
*/
|
|
trace_hardirqs_fixup();
|
|
|
|
tsk = current;
|
|
mm = tsk->mm;
|
|
prefetchw(&mm->mmap_sem);
|
|
|
|
/* get the address */
|
|
address = read_cr2();
|
|
|
|
si_code = SEGV_MAPERR;
|
|
|
|
if (notify_page_fault(regs))
|
|
return;
|
|
if (unlikely(kmmio_fault(regs, address)))
|
|
return;
|
|
|
|
/*
|
|
* We fault-in kernel-space virtual memory on-demand. The
|
|
* 'reference' page table is init_mm.pgd.
|
|
*
|
|
* NOTE! We MUST NOT take any locks for this case. We may
|
|
* be in an interrupt or a critical region, and should
|
|
* only copy the information from the master page table,
|
|
* nothing more.
|
|
*
|
|
* This verifies that the fault happens in kernel space
|
|
* (error_code & 4) == 0, and that the fault was not a
|
|
* protection error (error_code & 9) == 0.
|
|
*/
|
|
#ifdef CONFIG_X86_32
|
|
if (unlikely(address >= TASK_SIZE)) {
|
|
#else
|
|
if (unlikely(address >= TASK_SIZE64)) {
|
|
#endif
|
|
if (!(error_code & (PF_RSVD|PF_USER|PF_PROT)) &&
|
|
vmalloc_fault(address) >= 0)
|
|
return;
|
|
|
|
/* Can handle a stale RO->RW TLB */
|
|
if (spurious_fault(address, error_code))
|
|
return;
|
|
|
|
/*
|
|
* Don't take the mm semaphore here. If we fixup a prefetch
|
|
* fault we could otherwise deadlock.
|
|
*/
|
|
goto bad_area_nosemaphore;
|
|
}
|
|
|
|
|
|
#ifdef CONFIG_X86_32
|
|
/* It's safe to allow irq's after cr2 has been saved and the vmalloc
|
|
fault has been handled. */
|
|
if (regs->flags & (X86_EFLAGS_IF | X86_VM_MASK))
|
|
local_irq_enable();
|
|
|
|
/*
|
|
* If we're in an interrupt, have no user context or are running in an
|
|
* atomic region then we must not take the fault.
|
|
*/
|
|
if (in_atomic() || !mm)
|
|
goto bad_area_nosemaphore;
|
|
#else /* CONFIG_X86_64 */
|
|
if (likely(regs->flags & X86_EFLAGS_IF))
|
|
local_irq_enable();
|
|
|
|
if (unlikely(error_code & PF_RSVD))
|
|
pgtable_bad(address, regs, error_code);
|
|
|
|
/*
|
|
* If we're in an interrupt, have no user context or are running in an
|
|
* atomic region then we must not take the fault.
|
|
*/
|
|
if (unlikely(in_atomic() || !mm))
|
|
goto bad_area_nosemaphore;
|
|
|
|
/*
|
|
* User-mode registers count as a user access even for any
|
|
* potential system fault or CPU buglet.
|
|
*/
|
|
if (user_mode_vm(regs))
|
|
error_code |= PF_USER;
|
|
again:
|
|
#endif
|
|
/* When running in the kernel we expect faults to occur only to
|
|
* addresses in user space. All other faults represent errors in the
|
|
* kernel and should generate an OOPS. Unfortunately, in the case of an
|
|
* erroneous fault occurring in a code path which already holds mmap_sem
|
|
* we will deadlock attempting to validate the fault against the
|
|
* address space. Luckily the kernel only validly references user
|
|
* space from well defined areas of code, which are listed in the
|
|
* exceptions table.
|
|
*
|
|
* As the vast majority of faults will be valid we will only perform
|
|
* the source reference check when there is a possibility of a deadlock.
|
|
* Attempt to lock the address space, if we cannot we then validate the
|
|
* source. If this is invalid we can skip the address space check,
|
|
* thus avoiding the deadlock.
|
|
*/
|
|
if (!down_read_trylock(&mm->mmap_sem)) {
|
|
if ((error_code & PF_USER) == 0 &&
|
|
!search_exception_tables(regs->ip))
|
|
goto bad_area_nosemaphore;
|
|
down_read(&mm->mmap_sem);
|
|
}
|
|
|
|
vma = find_vma(mm, address);
|
|
if (!vma)
|
|
goto bad_area;
|
|
if (vma->vm_start <= address)
|
|
goto good_area;
|
|
if (!(vma->vm_flags & VM_GROWSDOWN))
|
|
goto bad_area;
|
|
if (error_code & PF_USER) {
|
|
/*
|
|
* Accessing the stack below %sp is always a bug.
|
|
* The large cushion allows instructions like enter
|
|
* and pusha to work. ("enter $65535,$31" pushes
|
|
* 32 pointers and then decrements %sp by 65535.)
|
|
*/
|
|
if (address + 65536 + 32 * sizeof(unsigned long) < regs->sp)
|
|
goto bad_area;
|
|
}
|
|
if (expand_stack(vma, address))
|
|
goto bad_area;
|
|
/*
|
|
* Ok, we have a good vm_area for this memory access, so
|
|
* we can handle it..
|
|
*/
|
|
good_area:
|
|
si_code = SEGV_ACCERR;
|
|
write = 0;
|
|
switch (error_code & (PF_PROT|PF_WRITE)) {
|
|
default: /* 3: write, present */
|
|
/* fall through */
|
|
case PF_WRITE: /* write, not present */
|
|
if (!(vma->vm_flags & VM_WRITE))
|
|
goto bad_area;
|
|
write++;
|
|
break;
|
|
case PF_PROT: /* read, present */
|
|
goto bad_area;
|
|
case 0: /* read, not present */
|
|
if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
|
|
goto bad_area;
|
|
}
|
|
|
|
#ifdef CONFIG_X86_32
|
|
survive:
|
|
#endif
|
|
/*
|
|
* If for any reason at all we couldn't handle the fault,
|
|
* make sure we exit gracefully rather than endlessly redo
|
|
* the fault.
|
|
*/
|
|
fault = handle_mm_fault(mm, vma, address, write);
|
|
if (unlikely(fault & VM_FAULT_ERROR)) {
|
|
if (fault & VM_FAULT_OOM)
|
|
goto out_of_memory;
|
|
else if (fault & VM_FAULT_SIGBUS)
|
|
goto do_sigbus;
|
|
BUG();
|
|
}
|
|
if (fault & VM_FAULT_MAJOR)
|
|
tsk->maj_flt++;
|
|
else
|
|
tsk->min_flt++;
|
|
|
|
#ifdef CONFIG_X86_32
|
|
/*
|
|
* Did it hit the DOS screen memory VA from vm86 mode?
|
|
*/
|
|
if (v8086_mode(regs)) {
|
|
unsigned long bit = (address - 0xA0000) >> PAGE_SHIFT;
|
|
if (bit < 32)
|
|
tsk->thread.screen_bitmap |= 1 << bit;
|
|
}
|
|
#endif
|
|
up_read(&mm->mmap_sem);
|
|
return;
|
|
|
|
/*
|
|
* Something tried to access memory that isn't in our memory map..
|
|
* Fix it, but check if it's kernel or user first..
|
|
*/
|
|
bad_area:
|
|
up_read(&mm->mmap_sem);
|
|
|
|
bad_area_nosemaphore:
|
|
/* User mode accesses just cause a SIGSEGV */
|
|
if (error_code & PF_USER) {
|
|
/*
|
|
* It's possible to have interrupts off here.
|
|
*/
|
|
local_irq_enable();
|
|
|
|
/*
|
|
* Valid to do another page fault here because this one came
|
|
* from user space.
|
|
*/
|
|
if (is_prefetch(regs, address, error_code))
|
|
return;
|
|
|
|
if (is_errata100(regs, address))
|
|
return;
|
|
|
|
if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
|
|
printk_ratelimit()) {
|
|
printk(
|
|
"%s%s[%d]: segfault at %lx ip %p sp %p error %lx",
|
|
task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
|
|
tsk->comm, task_pid_nr(tsk), address,
|
|
(void *) regs->ip, (void *) regs->sp, error_code);
|
|
print_vma_addr(" in ", regs->ip);
|
|
printk("\n");
|
|
}
|
|
|
|
tsk->thread.cr2 = address;
|
|
/* Kernel addresses are always protection faults */
|
|
tsk->thread.error_code = error_code | (address >= TASK_SIZE);
|
|
tsk->thread.trap_no = 14;
|
|
force_sig_info_fault(SIGSEGV, si_code, address, tsk);
|
|
return;
|
|
}
|
|
|
|
if (is_f00f_bug(regs, address))
|
|
return;
|
|
|
|
no_context:
|
|
/* Are we prepared to handle this kernel fault? */
|
|
if (fixup_exception(regs))
|
|
return;
|
|
|
|
/*
|
|
* X86_32
|
|
* Valid to do another page fault here, because if this fault
|
|
* had been triggered by is_prefetch fixup_exception would have
|
|
* handled it.
|
|
*
|
|
* X86_64
|
|
* Hall of shame of CPU/BIOS bugs.
|
|
*/
|
|
if (is_prefetch(regs, address, error_code))
|
|
return;
|
|
|
|
if (is_errata93(regs, address))
|
|
return;
|
|
|
|
/*
|
|
* Oops. The kernel tried to access some bad page. We'll have to
|
|
* terminate things with extreme prejudice.
|
|
*/
|
|
#ifdef CONFIG_X86_32
|
|
bust_spinlocks(1);
|
|
#else
|
|
flags = oops_begin();
|
|
#endif
|
|
|
|
show_fault_oops(regs, error_code, address);
|
|
|
|
tsk->thread.cr2 = address;
|
|
tsk->thread.trap_no = 14;
|
|
tsk->thread.error_code = error_code;
|
|
|
|
#ifdef CONFIG_X86_32
|
|
die("Oops", regs, error_code);
|
|
bust_spinlocks(0);
|
|
do_exit(SIGKILL);
|
|
#else
|
|
if (__die("Oops", regs, error_code))
|
|
regs = NULL;
|
|
/* Executive summary in case the body of the oops scrolled away */
|
|
printk(KERN_EMERG "CR2: %016lx\n", address);
|
|
oops_end(flags, regs, SIGKILL);
|
|
#endif
|
|
|
|
/*
|
|
* We ran out of memory, or some other thing happened to us that made
|
|
* us unable to handle the page fault gracefully.
|
|
*/
|
|
out_of_memory:
|
|
up_read(&mm->mmap_sem);
|
|
if (is_global_init(tsk)) {
|
|
yield();
|
|
#ifdef CONFIG_X86_32
|
|
down_read(&mm->mmap_sem);
|
|
goto survive;
|
|
#else
|
|
goto again;
|
|
#endif
|
|
}
|
|
|
|
printk("VM: killing process %s\n", tsk->comm);
|
|
if (error_code & PF_USER)
|
|
do_group_exit(SIGKILL);
|
|
goto no_context;
|
|
|
|
do_sigbus:
|
|
up_read(&mm->mmap_sem);
|
|
|
|
/* Kernel mode? Handle exceptions or die */
|
|
if (!(error_code & PF_USER))
|
|
goto no_context;
|
|
#ifdef CONFIG_X86_32
|
|
/* User space => ok to do another page fault */
|
|
if (is_prefetch(regs, address, error_code))
|
|
return;
|
|
#endif
|
|
tsk->thread.cr2 = address;
|
|
tsk->thread.error_code = error_code;
|
|
tsk->thread.trap_no = 14;
|
|
force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk);
|
|
}
|
|
|
|
DEFINE_SPINLOCK(pgd_lock);
|
|
LIST_HEAD(pgd_list);
|
|
|
|
void vmalloc_sync_all(void)
|
|
{
|
|
#ifdef CONFIG_X86_32
|
|
unsigned long start = VMALLOC_START & PGDIR_MASK;
|
|
unsigned long address;
|
|
|
|
if (SHARED_KERNEL_PMD)
|
|
return;
|
|
|
|
BUILD_BUG_ON(TASK_SIZE & ~PGDIR_MASK);
|
|
for (address = start; address >= TASK_SIZE; address += PGDIR_SIZE) {
|
|
unsigned long flags;
|
|
struct page *page;
|
|
|
|
spin_lock_irqsave(&pgd_lock, flags);
|
|
list_for_each_entry(page, &pgd_list, lru) {
|
|
if (!vmalloc_sync_one(page_address(page),
|
|
address))
|
|
break;
|
|
}
|
|
spin_unlock_irqrestore(&pgd_lock, flags);
|
|
}
|
|
#else /* CONFIG_X86_64 */
|
|
unsigned long start = VMALLOC_START & PGDIR_MASK;
|
|
unsigned long address;
|
|
|
|
for (address = start; address <= VMALLOC_END; address += PGDIR_SIZE) {
|
|
const pgd_t *pgd_ref = pgd_offset_k(address);
|
|
unsigned long flags;
|
|
struct page *page;
|
|
|
|
if (pgd_none(*pgd_ref))
|
|
continue;
|
|
spin_lock_irqsave(&pgd_lock, flags);
|
|
list_for_each_entry(page, &pgd_list, lru) {
|
|
pgd_t *pgd;
|
|
pgd = (pgd_t *)page_address(page) + pgd_index(address);
|
|
if (pgd_none(*pgd))
|
|
set_pgd(pgd, *pgd_ref);
|
|
else
|
|
BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref));
|
|
}
|
|
spin_unlock_irqrestore(&pgd_lock, flags);
|
|
}
|
|
#endif
|
|
}
|