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Diffstat (limited to 'arch/x86/mm/fault_64.c')
-rw-r--r--arch/x86/mm/fault_64.c623
1 files changed, 0 insertions, 623 deletions
diff --git a/arch/x86/mm/fault_64.c b/arch/x86/mm/fault_64.c
deleted file mode 100644
index 0e26230669ca..000000000000
--- a/arch/x86/mm/fault_64.c
+++ /dev/null
@@ -1,623 +0,0 @@
-/*
- * linux/arch/x86-64/mm/fault.c
- *
- * Copyright (C) 1995 Linus Torvalds
- * Copyright (C) 2001,2002 Andi Kleen, SuSE Labs.
- */
-
-#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/interrupt.h>
-#include <linux/init.h>
-#include <linux/tty.h>
-#include <linux/vt_kern.h> /* For unblank_screen() */
-#include <linux/compiler.h>
-#include <linux/vmalloc.h>
-#include <linux/module.h>
-#include <linux/kprobes.h>
-#include <linux/uaccess.h>
-#include <linux/kdebug.h>
-#include <linux/kprobes.h>
-
-#include <asm/system.h>
-#include <asm/pgalloc.h>
-#include <asm/smp.h>
-#include <asm/tlbflush.h>
-#include <asm/proto.h>
-#include <asm-generic/sections.h>
-
-/* Page fault error code bits */
-#define PF_PROT (1<<0) /* or no page found */
-#define PF_WRITE (1<<1)
-#define PF_USER (1<<2)
-#define PF_RSVD (1<<3)
-#define PF_INSTR (1<<4)
-
-#ifdef CONFIG_KPROBES
-static inline int notify_page_fault(struct pt_regs *regs)
-{
- int ret = 0;
-
- /* kprobe_running() needs smp_processor_id() */
- if (!user_mode(regs)) {
- preempt_disable();
- if (kprobe_running() && kprobe_fault_handler(regs, 14))
- ret = 1;
- preempt_enable();
- }
-
- return ret;
-}
-#else
-static inline int notify_page_fault(struct pt_regs *regs)
-{
- return 0;
-}
-#endif
-
-/* 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 & PF_INSTR)
- return 0;
-
- instr = (unsigned char __user *)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 (probe_kernel_address(instr, opcode))
- 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 (probe_kernel_address(instr, opcode))
- 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 probe_kernel_address((unsigned long *)p, dummy);
-}
-
-void dump_pagetable(unsigned long address)
-{
- pgd_t *pgd;
- pud_t *pud;
- pmd_t *pmd;
- pte_t *pte;
-
- pgd = (pgd_t *)read_cr3();
-
- pgd = __va((unsigned long)pgd & PHYSICAL_PAGE_MASK);
- pgd += pgd_index(address);
- if (bad_address(pgd)) goto bad;
- printk("PGD %lx ", pgd_val(*pgd));
- if (!pgd_present(*pgd)) goto ret;
-
- pud = pud_offset(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) || pmd_large(*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;
-}
-
-static noinline void pgtable_bad(unsigned long address, struct pt_regs *regs,
- unsigned long error_code)
-{
- unsigned long flags = oops_begin();
- struct task_struct *tsk;
-
- printk(KERN_ALERT "%s: Corrupted page table at address %lx\n",
- current->comm, address);
- dump_pagetable(address);
- tsk = current;
- tsk->thread.cr2 = address;
- tsk->thread.trap_no = 14;
- tsk->thread.error_code = error_code;
- __die("Bad pagetable", regs, error_code);
- oops_end(flags);
- do_exit(SIGKILL);
-}
-
-/*
- * Handle a fault on the vmalloc 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);
- 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;
-}
-
-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.
- */
-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, fault;
- unsigned long flags;
- siginfo_t info;
-
- /*
- * 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();
-
- 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 & 9) == 0.
- */
- if (unlikely(address >= TASK_SIZE64)) {
- /*
- * Don't check for the module range here: its PML4
- * is always initialized because it's shared with the main
- * kernel text. Only vmalloc may need PML4 syncups.
- */
- if (!(error_code & (PF_RSVD|PF_USER|PF_PROT)) &&
- ((address >= VMALLOC_START && address < VMALLOC_END))) {
- if (vmalloc_fault(address) >= 0)
- return;
- }
- if (notify_page_fault(regs))
- return;
- /*
- * Don't take the mm semaphore here. If we fixup a prefetch
- * fault we could otherwise deadlock.
- */
- goto bad_area_nosemaphore;
- }
-
- if (notify_page_fault(regs))
- return;
-
- if (likely(regs->eflags & X86_EFLAGS_IF))
- local_irq_enable();
-
- if (unlikely(error_code & PF_RSVD))
- 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;
-
- /*
- * 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:
- /* 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->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) {
- /* Allow userspace just enough access below the stack pointer
- * to let the 'enter' instruction work.
- */
- if (address + 65536 + 32 * sizeof(unsigned long) < 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 & (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;
- }
-
- /*
- * 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++;
- 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();
-
- 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 (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
- printk_ratelimit()) {
- printk(
- "%s%s[%d]: segfault at %lx rip %lx rsp %lx 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);
- dump_pagetable(address);
- tsk->thread.cr2 = address;
- tsk->thread.trap_no = 14;
- tsk->thread.error_code = error_code;
- __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 (is_global_init(current)) {
- yield();
- goto again;
- }
- printk("VM: killing process %s\n", tsk->comm);
- if (error_code & 4)
- 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;
-
- 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;
-}
-
-DEFINE_SPINLOCK(pgd_lock);
-LIST_HEAD(pgd_list);
-
-void vmalloc_sync_all(void)
-{
- /* Note that races in the updates of insync and start aren't
- problematic:
- insync can only get set bits added, and updates to start are only
- improving performance (without affecting correctness if undone). */
- static DECLARE_BITMAP(insync, PTRS_PER_PGD);
- static unsigned long start = VMALLOC_START & PGDIR_MASK;
- unsigned long address;
-
- for (address = start; address <= VMALLOC_END; address += PGDIR_SIZE) {
- if (!test_bit(pgd_index(address), insync)) {
- const pgd_t *pgd_ref = pgd_offset_k(address);
- struct page *page;
-
- if (pgd_none(*pgd_ref))
- continue;
- spin_lock(&pgd_lock);
- 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(&pgd_lock);
- set_bit(pgd_index(address), insync);
- }
- if (address == start)
- start = address + PGDIR_SIZE;
- }
- /* Check that there is no need to do the same for the modules area. */
- BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
- BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
- (__START_KERNEL & PGDIR_MASK)));
-}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.