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Diffstat (limited to 'arch/x86_64/mm/fault.c')
-rw-r--r--arch/x86_64/mm/fault.c573
1 files changed, 0 insertions, 573 deletions
diff --git a/arch/x86_64/mm/fault.c b/arch/x86_64/mm/fault.c
deleted file mode 100644
index b75b872ec15..00000000000
--- a/arch/x86_64/mm/fault.c
+++ /dev/null
@@ -1,573 +0,0 @@
-/*
- * linux/arch/x86-64/mm/fault.c
- *
- * Copyright (C) 1995 Linus Torvalds
- * Copyright (C) 2001,2002 Andi Kleen, SuSE Labs.
- */
-
-#include <linux/config.h>
-#include <linux/signal.h>
-#include <linux/sched.h>
-#include <linux/kernel.h>
-#include <linux/errno.h>
-#include <linux/string.h>
-#include <linux/types.h>
-#include <linux/ptrace.h>
-#include <linux/mman.h>
-#include <linux/mm.h>
-#include <linux/smp.h>
-#include <linux/smp_lock.h>
-#include <linux/interrupt.h>
-#include <linux/init.h>
-#include <linux/tty.h>
-#include <linux/vt_kern.h> /* For unblank_screen() */
-#include <linux/compiler.h>
-#include <linux/module.h>
-#include <linux/kprobes.h>
-
-#include <asm/system.h>
-#include <asm/uaccess.h>
-#include <asm/pgalloc.h>
-#include <asm/smp.h>
-#include <asm/tlbflush.h>
-#include <asm/proto.h>
-#include <asm/kdebug.h>
-#include <asm-generic/sections.h>
-#include <asm/kdebug.h>
-
-void bust_spinlocks(int yes)
-{
- int loglevel_save = console_loglevel;
- if (yes) {
- oops_in_progress = 1;
- } else {
-#ifdef CONFIG_VT
- unblank_screen();
-#endif
- oops_in_progress = 0;
- /*
- * OK, the message is on the console. Now we call printk()
- * without oops_in_progress set so that printk will give klogd
- * a poke. Hold onto your hats...
- */
- console_loglevel = 15; /* NMI oopser may have shut the console up */
- printk(" ");
- console_loglevel = loglevel_save;
- }
-}
-
-/* Sometimes the CPU reports invalid exceptions on prefetch.
- Check that here and ignore.
- Opcode checker based on code by Richard Brunner */
-static noinline int is_prefetch(struct pt_regs *regs, unsigned long addr,
- unsigned long error_code)
-{
- unsigned char *instr;
- int scan_more = 1;
- int prefetch = 0;
- unsigned char *max_instr;
-
- /* If it was a exec fault ignore */
- if (error_code & (1<<4))
- return 0;
-
- instr = (unsigned char *)convert_rip_to_linear(current, regs);
- max_instr = instr + 15;
-
- if (user_mode(regs) && instr >= (unsigned char *)TASK_SIZE)
- return 0;
-
- while (scan_more && instr < max_instr) {
- unsigned char opcode;
- unsigned char instr_hi;
- unsigned char instr_lo;
-
- if (__get_user(opcode, instr))
- break;
-
- instr_hi = opcode & 0xf0;
- instr_lo = opcode & 0x0f;
- instr++;
-
- switch (instr_hi) {
- case 0x20:
- case 0x30:
- /* Values 0x26,0x2E,0x36,0x3E are valid x86
- prefixes. In long mode, the CPU will signal
- invalid opcode if some of these prefixes are
- present so we will never get here anyway */
- scan_more = ((instr_lo & 7) == 0x6);
- break;
-
- case 0x40:
- /* In AMD64 long mode, 0x40 to 0x4F are valid REX prefixes
- Need to figure out under what instruction mode the
- instruction was issued ... */
- /* Could check the LDT for lm, but for now it's good
- enough to assume that long mode only uses well known
- segments or kernel. */
- scan_more = (!user_mode(regs)) || (regs->cs == __USER_CS);
- break;
-
- case 0x60:
- /* 0x64 thru 0x67 are valid prefixes in all modes. */
- scan_more = (instr_lo & 0xC) == 0x4;
- break;
- case 0xF0:
- /* 0xF0, 0xF2, and 0xF3 are valid prefixes in all modes. */
- scan_more = !instr_lo || (instr_lo>>1) == 1;
- break;
- case 0x00:
- /* Prefetch instruction is 0x0F0D or 0x0F18 */
- scan_more = 0;
- if (__get_user(opcode, instr))
- break;
- prefetch = (instr_lo == 0xF) &&
- (opcode == 0x0D || opcode == 0x18);
- break;
- default:
- scan_more = 0;
- break;
- }
- }
- return prefetch;
-}
-
-static int bad_address(void *p)
-{
- unsigned long dummy;
- return __get_user(dummy, (unsigned long *)p);
-}
-
-void dump_pagetable(unsigned long address)
-{
- pgd_t *pgd;
- pud_t *pud;
- pmd_t *pmd;
- pte_t *pte;
-
- asm("movq %%cr3,%0" : "=r" (pgd));
-
- pgd = __va((unsigned long)pgd & PHYSICAL_PAGE_MASK);
- pgd += pgd_index(address);
- printk("PGD %lx ", pgd_val(*pgd));
- if (bad_address(pgd)) goto bad;
- if (!pgd_present(*pgd)) goto ret;
-
- pud = __pud_offset_k((pud_t *)pgd_page(*pgd), address);
- if (bad_address(pud)) goto bad;
- printk("PUD %lx ", pud_val(*pud));
- if (!pud_present(*pud)) goto ret;
-
- pmd = pmd_offset(pud, address);
- if (bad_address(pmd)) goto bad;
- printk("PMD %lx ", pmd_val(*pmd));
- if (!pmd_present(*pmd)) goto ret;
-
- pte = pte_offset_kernel(pmd, address);
- if (bad_address(pte)) goto bad;
- printk("PTE %lx", pte_val(*pte));
-ret:
- printk("\n");
- return;
-bad:
- printk("BAD\n");
-}
-
-static const char errata93_warning[] =
-KERN_ERR "******* Your BIOS seems to not contain a fix for K8 errata #93\n"
-KERN_ERR "******* Working around it, but it may cause SEGVs or burn power.\n"
-KERN_ERR "******* Please consider a BIOS update.\n"
-KERN_ERR "******* Disabling USB legacy in the BIOS may also help.\n";
-
-/* Workaround for K8 erratum #93 & buggy BIOS.
- BIOS SMM functions are required to use a specific workaround
- to avoid corruption of the 64bit RIP register on C stepping K8.
- A lot of BIOS that didn't get tested properly miss this.
- The OS sees this as a page fault with the upper 32bits of RIP cleared.
- Try to work around it here.
- Note we only handle faults in kernel here. */
-
-static int is_errata93(struct pt_regs *regs, unsigned long address)
-{
- static int warned;
- if (address != regs->rip)
- return 0;
- if ((address >> 32) != 0)
- return 0;
- address |= 0xffffffffUL << 32;
- if ((address >= (u64)_stext && address <= (u64)_etext) ||
- (address >= MODULES_VADDR && address <= MODULES_END)) {
- if (!warned) {
- printk(errata93_warning);
- warned = 1;
- }
- regs->rip = address;
- return 1;
- }
- return 0;
-}
-
-int unhandled_signal(struct task_struct *tsk, int sig)
-{
- if (tsk->pid == 1)
- return 1;
- if (tsk->ptrace & PT_PTRACED)
- return 0;
- return (tsk->sighand->action[sig-1].sa.sa_handler == SIG_IGN) ||
- (tsk->sighand->action[sig-1].sa.sa_handler == SIG_DFL);
-}
-
-static noinline void pgtable_bad(unsigned long address, struct pt_regs *regs,
- unsigned long error_code)
-{
- unsigned long flags = oops_begin();
-
- printk(KERN_ALERT "%s: Corrupted page table at address %lx\n",
- current->comm, address);
- dump_pagetable(address);
- __die("Bad pagetable", regs, error_code);
- oops_end(flags);
- do_exit(SIGKILL);
-}
-
-/*
- * Handle a fault on the vmalloc or module mapping area
- *
- * This assumes no large pages in there.
- */
-static int vmalloc_fault(unsigned long address)
-{
- pgd_t *pgd, *pgd_ref;
- pud_t *pud, *pud_ref;
- pmd_t *pmd, *pmd_ref;
- pte_t *pte, *pte_ref;
-
- /* 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);
-
- /* 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(*pud) != pud_page(*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();
- __flush_tlb_all();
- return 0;
-}
-
-int page_fault_trace = 0;
-int exception_trace = 1;
-
-/*
- * This routine handles page faults. It determines the address,
- * and the problem, and then passes it off to one of the appropriate
- * routines.
- *
- * error_code:
- * bit 0 == 0 means no page found, 1 means protection fault
- * bit 1 == 0 means read, 1 means write
- * bit 2 == 0 means kernel, 1 means user-mode
- * bit 3 == 1 means fault was an instruction fetch
- */
-asmlinkage 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;
- const struct exception_table_entry *fixup;
- int write;
- unsigned long flags;
- siginfo_t info;
-
-#ifdef CONFIG_CHECKING
- {
- unsigned long gs;
- struct x8664_pda *pda = cpu_pda + stack_smp_processor_id();
- rdmsrl(MSR_GS_BASE, gs);
- if (gs != (unsigned long)pda) {
- wrmsrl(MSR_GS_BASE, pda);
- printk("page_fault: wrong gs %lx expected %p\n", gs, pda);
- }
- }
-#endif
-
- /* get the address */
- __asm__("movq %%cr2,%0":"=r" (address));
- if (notify_die(DIE_PAGE_FAULT, "page fault", regs, error_code, 14,
- SIGSEGV) == NOTIFY_STOP)
- return;
-
- if (likely(regs->eflags & X86_EFLAGS_IF))
- local_irq_enable();
-
- if (unlikely(page_fault_trace))
- printk("pagefault rip:%lx rsp:%lx cs:%lu ss:%lu address %lx error %lx\n",
- regs->rip,regs->rsp,regs->cs,regs->ss,address,error_code);
-
- tsk = current;
- mm = tsk->mm;
- info.si_code = SEGV_MAPERR;
-
-
- /*
- * 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 & 1) == 0.
- */
- if (unlikely(address >= TASK_SIZE64)) {
- if (!(error_code & 5) &&
- ((address >= VMALLOC_START && address < VMALLOC_END) ||
- (address >= MODULES_VADDR && address < MODULES_END))) {
- if (vmalloc_fault(address) < 0)
- goto bad_area_nosemaphore;
- return;
- }
- /*
- * Don't take the mm semaphore here. If we fixup a prefetch
- * fault we could otherwise deadlock.
- */
- goto bad_area_nosemaphore;
- }
-
- if (unlikely(error_code & (1 << 3)))
- pgtable_bad(address, regs, error_code);
-
- /*
- * If we're in an interrupt or have no user
- * context, we must not take the fault..
- */
- if (unlikely(in_atomic() || !mm))
- goto bad_area_nosemaphore;
-
- again:
- /* 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. Unfortunatly, in the case of an
- * erroneous fault occuring 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 possibilty 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 & 4) == 0 &&
- !search_exception_tables(regs->rip))
- goto bad_area_nosemaphore;
- down_read(&mm->mmap_sem);
- }
-
- vma = find_vma(mm, address);
- if (!vma)
- goto bad_area;
- if (likely(vma->vm_start <= address))
- goto good_area;
- if (!(vma->vm_flags & VM_GROWSDOWN))
- goto bad_area;
- if (error_code & 4) {
- // XXX: align red zone size with ABI
- if (address + 128 < regs->rsp)
- 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:
- info.si_code = SEGV_ACCERR;
- write = 0;
- switch (error_code & 3) {
- default: /* 3: write, present */
- /* fall through */
- case 2: /* write, not present */
- if (!(vma->vm_flags & VM_WRITE))
- goto bad_area;
- write++;
- break;
- case 1: /* read, present */
- goto bad_area;
- case 0: /* read, not present */
- if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
- goto bad_area;
- }
-
- /*
- * If for any reason at all we couldn't handle the fault,
- * make sure we exit gracefully rather than endlessly redo
- * the fault.
- */
- switch (handle_mm_fault(mm, vma, address, write)) {
- case VM_FAULT_MINOR:
- tsk->min_flt++;
- break;
- case VM_FAULT_MAJOR:
- tsk->maj_flt++;
- break;
- case VM_FAULT_SIGBUS:
- goto do_sigbus;
- default:
- goto out_of_memory;
- }
-
- 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 & 4) {
- if (is_prefetch(regs, address, error_code))
- return;
-
- /* Work around K8 erratum #100 K8 in compat mode
- occasionally jumps to illegal addresses >4GB. We
- catch this here in the page fault handler because
- these addresses are not reachable. Just detect this
- case and return. Any code segment in LDT is
- compatibility mode. */
- if ((regs->cs == __USER32_CS || (regs->cs & (1<<2))) &&
- (address >> 32))
- return;
-
- if (exception_trace && unhandled_signal(tsk, SIGSEGV)) {
- printk(
- "%s%s[%d]: segfault at %016lx rip %016lx rsp %016lx error %lx\n",
- tsk->pid > 1 ? KERN_INFO : KERN_EMERG,
- tsk->comm, tsk->pid, address, regs->rip,
- regs->rsp, error_code);
- }
-
- tsk->thread.cr2 = address;
- /* Kernel addresses are always protection faults */
- tsk->thread.error_code = error_code | (address >= TASK_SIZE);
- tsk->thread.trap_no = 14;
- info.si_signo = SIGSEGV;
- info.si_errno = 0;
- /* info.si_code has been set above */
- info.si_addr = (void __user *)address;
- force_sig_info(SIGSEGV, &info, tsk);
- return;
- }
-
-no_context:
-
- /* Are we prepared to handle this kernel fault? */
- fixup = search_exception_tables(regs->rip);
- if (fixup) {
- regs->rip = fixup->fixup;
- return;
- }
-
- /*
- * 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.
- */
-
- flags = oops_begin();
-
- if (address < PAGE_SIZE)
- printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
- else
- printk(KERN_ALERT "Unable to handle kernel paging request");
- printk(" at %016lx RIP: \n" KERN_ALERT,address);
- printk_address(regs->rip);
- printk("\n");
- dump_pagetable(address);
- __die("Oops", regs, error_code);
- /* Executive summary in case the body of the oops scrolled away */
- printk(KERN_EMERG "CR2: %016lx\n", address);
- oops_end(flags);
- do_exit(SIGKILL);
-
-/*
- * 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 (current->pid == 1) {
- yield();
- goto again;
- }
- printk("VM: killing process %s\n", tsk->comm);
- if (error_code & 4)
- do_exit(SIGKILL);
- goto no_context;
-
-do_sigbus:
- up_read(&mm->mmap_sem);
-
- /* Kernel mode? Handle exceptions or die */
- if (!(error_code & 4))
- goto no_context;
-
- tsk->thread.cr2 = address;
- tsk->thread.error_code = error_code;
- tsk->thread.trap_no = 14;
- info.si_signo = SIGBUS;
- info.si_errno = 0;
- info.si_code = BUS_ADRERR;
- info.si_addr = (void __user *)address;
- force_sig_info(SIGBUS, &info, tsk);
- return;
-}
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