#include <linux/highmem.h>
#include <linux/module.h>
#include <linux/kprobes.h>
+#include <linux/uaccess.h>
#include <asm/system.h>
-#include <asm/uaccess.h>
#include <asm/desc.h>
#include <asm/kdebug.h>
+#include <asm/segment.h>
extern void die(const char *,struct pt_regs *,long);
+static ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain);
+
+int register_page_fault_notifier(struct notifier_block *nb)
+{
+ vmalloc_sync_all();
+ return atomic_notifier_chain_register(¬ify_page_fault_chain, nb);
+}
+EXPORT_SYMBOL_GPL(register_page_fault_notifier);
+
+int unregister_page_fault_notifier(struct notifier_block *nb)
+{
+ return atomic_notifier_chain_unregister(¬ify_page_fault_chain, nb);
+}
+EXPORT_SYMBOL_GPL(unregister_page_fault_notifier);
+
+static inline int notify_page_fault(enum die_val val, const char *str,
+ struct pt_regs *regs, long err, int trap, int sig)
+{
+ struct die_args args = {
+ .regs = regs,
+ .str = str,
+ .err = err,
+ .trapnr = trap,
+ .signr = sig
+ };
+ return atomic_notifier_call_chain(¬ify_page_fault_chain, val, &args);
+}
+
/*
* Unlock any spinlocks which will prevent us from getting the
* message out
unsigned seg = regs->xcs & 0xffff;
u32 seg_ar, seg_limit, base, *desc;
- /* The standard kernel/user address space limit. */
- *eip_limit = (seg & 3) ? USER_DS.seg : KERNEL_DS.seg;
-
/* Unlikely, but must come before segment checks. */
- if (unlikely((regs->eflags & VM_MASK) != 0))
- return eip + (seg << 4);
+ if (unlikely(regs->eflags & VM_MASK)) {
+ base = seg << 4;
+ *eip_limit = base + 0xffff;
+ return base + (eip & 0xffff);
+ }
+
+ /* The standard kernel/user address space limit. */
+ *eip_limit = user_mode(regs) ? USER_DS.seg : KERNEL_DS.seg;
/* By far the most common cases. */
- if (likely(seg == __USER_CS || seg == __KERNEL_CS))
+ if (likely(SEGMENT_IS_FLAT_CODE(seg)))
return eip;
/* Check the segment exists, is within the current LDT/GDT size,
static int __is_prefetch(struct pt_regs *regs, unsigned long addr)
{
unsigned long limit;
- unsigned long instr = get_segment_eip (regs, &limit);
+ unsigned char *instr = (unsigned char *)get_segment_eip (regs, &limit);
int scan_more = 1;
int prefetch = 0;
int i;
unsigned char instr_hi;
unsigned char instr_lo;
- if (instr > limit)
+ if (instr > (unsigned char *)limit)
break;
- if (__get_user(opcode, (unsigned char __user *) instr))
+ if (probe_kernel_address(instr, opcode))
break;
instr_hi = opcode & 0xf0;
case 0x00:
/* Prefetch instruction is 0x0F0D or 0x0F18 */
scan_more = 0;
- if (instr > limit)
+ if (instr > (unsigned char *)limit)
break;
- if (__get_user(opcode, (unsigned char __user *) instr))
+ if (probe_kernel_address(instr, opcode))
break;
prefetch = (instr_lo == 0xF) &&
(opcode == 0x0D || opcode == 0x18);
if (unlikely(address >= TASK_SIZE)) {
if (!(error_code & 0x0000000d) && vmalloc_fault(address) >= 0)
return;
- if (notify_die(DIE_PAGE_FAULT, "page fault", regs, error_code, 14,
+ if (notify_page_fault(DIE_PAGE_FAULT, "page fault", regs, error_code, 14,
SIGSEGV) == NOTIFY_STOP)
return;
/*
goto bad_area_nosemaphore;
}
- if (notify_die(DIE_PAGE_FAULT, "page fault", regs, error_code, 14,
+ if (notify_page_fault(DIE_PAGE_FAULT, "page fault", regs, error_code, 14,
SIGSEGV) == NOTIFY_STOP)
return;
/* 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
+ * 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
goto bad_area;
if (error_code & 4) {
/*
- * accessing the stack below %esp is always a bug.
- * The "+ 32" is there due to some instructions (like
- * pusha) doing post-decrement on the stack and that
- * doesn't show up until later..
+ * Accessing the stack below %esp is always a bug.
+ * The large cushion allows instructions like enter
+ * and pusha to work. ("enter $65535,$31" pushes
+ * 32 pointers and then decrements %esp by 65535.)
*/
- if (address + 32 < regs->esp)
+ if (address + 65536 + 32 * sizeof(unsigned long) < regs->esp)
goto bad_area;
}
if (expand_stack(vma, address))
write = 0;
switch (error_code & 3) {
default: /* 3: write, present */
-#ifdef TEST_VERIFY_AREA
- if (regs->cs == KERNEL_CS)
- printk("WP fault at %08lx\n", regs->eip);
-#endif
- /* fall through */
+ /* fall through */
case 2: /* write, not present */
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
case 1: /* read, present */
goto bad_area;
case 0: /* read, not present */
- if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
+ if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
goto bad_area;
}
*/
out_of_memory:
up_read(&mm->mmap_sem);
- if (tsk->pid == 1) {
+ if (is_init(tsk)) {
yield();
down_read(&mm->mmap_sem);
goto survive;
}
- printk("VM: killing process %s\n", tsk->comm);
+ printk("VM: killing process %s(%d:#%u)\n",
+ tsk->comm, tsk->pid, tsk->xid);
if (error_code & 4)
do_exit(SIGKILL);
goto no_context;