aboutsummaryrefslogtreecommitdiff
path: root/arch/ppc64/mm/fault.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/ppc64/mm/fault.c')
-rw-r--r--arch/ppc64/mm/fault.c333
1 files changed, 0 insertions, 333 deletions
diff --git a/arch/ppc64/mm/fault.c b/arch/ppc64/mm/fault.c
deleted file mode 100644
index be3f25cf3e9..00000000000
--- a/arch/ppc64/mm/fault.c
+++ /dev/null
@@ -1,333 +0,0 @@
-/*
- * arch/ppc/mm/fault.c
- *
- * PowerPC version
- * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
- *
- * Derived from "arch/i386/mm/fault.c"
- * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
- *
- * Modified by Cort Dougan and Paul Mackerras.
- *
- * Modified for PPC64 by Dave Engebretsen (engebret@ibm.com)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
- */
-
-#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/mman.h>
-#include <linux/mm.h>
-#include <linux/interrupt.h>
-#include <linux/smp_lock.h>
-#include <linux/module.h>
-#include <linux/kprobes.h>
-
-#include <asm/page.h>
-#include <asm/pgtable.h>
-#include <asm/mmu.h>
-#include <asm/mmu_context.h>
-#include <asm/system.h>
-#include <asm/uaccess.h>
-#include <asm/kdebug.h>
-#include <asm/siginfo.h>
-
-/*
- * Check whether the instruction at regs->nip is a store using
- * an update addressing form which will update r1.
- */
-static int store_updates_sp(struct pt_regs *regs)
-{
- unsigned int inst;
-
- if (get_user(inst, (unsigned int __user *)regs->nip))
- return 0;
- /* check for 1 in the rA field */
- if (((inst >> 16) & 0x1f) != 1)
- return 0;
- /* check major opcode */
- switch (inst >> 26) {
- case 37: /* stwu */
- case 39: /* stbu */
- case 45: /* sthu */
- case 53: /* stfsu */
- case 55: /* stfdu */
- return 1;
- case 62: /* std or stdu */
- return (inst & 3) == 1;
- case 31:
- /* check minor opcode */
- switch ((inst >> 1) & 0x3ff) {
- case 181: /* stdux */
- case 183: /* stwux */
- case 247: /* stbux */
- case 439: /* sthux */
- case 695: /* stfsux */
- case 759: /* stfdux */
- return 1;
- }
- }
- return 0;
-}
-
-static void do_dabr(struct pt_regs *regs, unsigned long error_code)
-{
- siginfo_t info;
-
- if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code,
- 11, SIGSEGV) == NOTIFY_STOP)
- return;
-
- if (debugger_dabr_match(regs))
- return;
-
- /* Clear the DABR */
- set_dabr(0);
-
- /* Deliver the signal to userspace */
- info.si_signo = SIGTRAP;
- info.si_errno = 0;
- info.si_code = TRAP_HWBKPT;
- info.si_addr = (void __user *)regs->nip;
- force_sig_info(SIGTRAP, &info, current);
-}
-
-/*
- * The error_code parameter is
- * - DSISR for a non-SLB data access fault,
- * - SRR1 & 0x08000000 for a non-SLB instruction access fault
- * - 0 any SLB fault.
- * The return value is 0 if the fault was handled, or the signal
- * number if this is a kernel fault that can't be handled here.
- */
-int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address,
- unsigned long error_code)
-{
- struct vm_area_struct * vma;
- struct mm_struct *mm = current->mm;
- siginfo_t info;
- unsigned long code = SEGV_MAPERR;
- unsigned long is_write = error_code & DSISR_ISSTORE;
- unsigned long trap = TRAP(regs);
- unsigned long is_exec = trap == 0x400;
-
- BUG_ON((trap == 0x380) || (trap == 0x480));
-
- if (notify_die(DIE_PAGE_FAULT, "page_fault", regs, error_code,
- 11, SIGSEGV) == NOTIFY_STOP)
- return 0;
-
- if (trap == 0x300) {
- if (debugger_fault_handler(regs))
- return 0;
- }
-
- /* On a kernel SLB miss we can only check for a valid exception entry */
- if (!user_mode(regs) && (address >= TASK_SIZE))
- return SIGSEGV;
-
- if (error_code & DSISR_DABRMATCH) {
- do_dabr(regs, error_code);
- return 0;
- }
-
- if (in_atomic() || mm == NULL) {
- if (!user_mode(regs))
- return SIGSEGV;
- /* in_atomic() in user mode is really bad,
- as is current->mm == NULL. */
- printk(KERN_EMERG "Page fault in user mode with"
- "in_atomic() = %d mm = %p\n", in_atomic(), mm);
- printk(KERN_EMERG "NIP = %lx MSR = %lx\n",
- regs->nip, regs->msr);
- die("Weird page fault", regs, SIGSEGV);
- }
-
- /* 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 (!user_mode(regs) && !search_exception_tables(regs->nip))
- 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;
-
- /*
- * N.B. The POWER/Open ABI allows programs to access up to
- * 288 bytes below the stack pointer.
- * The kernel signal delivery code writes up to about 1.5kB
- * below the stack pointer (r1) before decrementing it.
- * The exec code can write slightly over 640kB to the stack
- * before setting the user r1. Thus we allow the stack to
- * expand to 1MB without further checks.
- */
- if (address + 0x100000 < vma->vm_end) {
- /* get user regs even if this fault is in kernel mode */
- struct pt_regs *uregs = current->thread.regs;
- if (uregs == NULL)
- goto bad_area;
-
- /*
- * A user-mode access to an address a long way below
- * the stack pointer is only valid if the instruction
- * is one which would update the stack pointer to the
- * address accessed if the instruction completed,
- * i.e. either stwu rs,n(r1) or stwux rs,r1,rb
- * (or the byte, halfword, float or double forms).
- *
- * If we don't check this then any write to the area
- * between the last mapped region and the stack will
- * expand the stack rather than segfaulting.
- */
- if (address + 2048 < uregs->gpr[1]
- && (!user_mode(regs) || !store_updates_sp(regs)))
- goto bad_area;
- }
-
- if (expand_stack(vma, address))
- goto bad_area;
-
-good_area:
- code = SEGV_ACCERR;
-
- if (is_exec) {
- /* protection fault */
- if (error_code & DSISR_PROTFAULT)
- goto bad_area;
- if (!(vma->vm_flags & VM_EXEC))
- goto bad_area;
- /* a write */
- } else if (is_write) {
- if (!(vma->vm_flags & VM_WRITE))
- goto bad_area;
- /* a read */
- } else {
- if (!(vma->vm_flags & VM_READ))
- goto bad_area;
- }
-
- survive:
- /*
- * 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, is_write)) {
-
- case VM_FAULT_MINOR:
- current->min_flt++;
- break;
- case VM_FAULT_MAJOR:
- current->maj_flt++;
- break;
- case VM_FAULT_SIGBUS:
- goto do_sigbus;
- case VM_FAULT_OOM:
- goto out_of_memory;
- default:
- BUG();
- }
-
- up_read(&mm->mmap_sem);
- return 0;
-
-bad_area:
- up_read(&mm->mmap_sem);
-
-bad_area_nosemaphore:
- /* User mode accesses cause a SIGSEGV */
- if (user_mode(regs)) {
- info.si_signo = SIGSEGV;
- info.si_errno = 0;
- info.si_code = code;
- info.si_addr = (void __user *) address;
- force_sig_info(SIGSEGV, &info, current);
- return 0;
- }
-
- if (trap == 0x400 && (error_code & DSISR_PROTFAULT)
- && printk_ratelimit())
- printk(KERN_CRIT "kernel tried to execute NX-protected"
- " page (%lx) - exploit attempt? (uid: %d)\n",
- address, current->uid);
-
- return SIGSEGV;
-
-/*
- * 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();
- down_read(&mm->mmap_sem);
- goto survive;
- }
- printk("VM: killing process %s\n", current->comm);
- if (user_mode(regs))
- do_exit(SIGKILL);
- return SIGKILL;
-
-do_sigbus:
- up_read(&mm->mmap_sem);
- if (user_mode(regs)) {
- info.si_signo = SIGBUS;
- info.si_errno = 0;
- info.si_code = BUS_ADRERR;
- info.si_addr = (void __user *)address;
- force_sig_info(SIGBUS, &info, current);
- return 0;
- }
- return SIGBUS;
-}
-
-/*
- * bad_page_fault is called when we have a bad access from the kernel.
- * It is called from do_page_fault above and from some of the procedures
- * in traps.c.
- */
-void bad_page_fault(struct pt_regs *regs, unsigned long address, int sig)
-{
- const struct exception_table_entry *entry;
-
- /* Are we prepared to handle this fault? */
- if ((entry = search_exception_tables(regs->nip)) != NULL) {
- regs->nip = entry->fixup;
- return;
- }
-
- /* kernel has accessed a bad area */
- die("Kernel access of bad area", regs, sig);
-}
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-12-16 14:01:34 +0000