#include <linux/vt_kern.h> /* For unblank_screen() */
#include <linux/highmem.h>
#include <linux/module.h>
+#include <linux/kprobes.h>
#include <asm/system.h>
#include <asm/uaccess.h>
-#include <asm/hardirq.h>
#include <asm/desc.h>
-#include <asm/tlbflush.h>
+#include <asm/kdebug.h>
extern void die(const char *,struct pt_regs *,long);
if (seg & (1<<2)) {
/* Must lock the LDT while reading it. */
down(¤t->mm->context.sem);
-#if 1
- /* horrible hack for 4/4 disabled kernels.
- I'm not quite sure what the TLB flush is good for,
- it's mindlessly copied from the read_ldt code */
- __flush_tlb_global();
- desc = kmap(current->mm->context.ldt_pages[(seg&~7)/PAGE_SIZE]);
- desc = (void *)desc + ((seg & ~7) % PAGE_SIZE);
-#else
desc = current->mm->context.ldt;
desc = (void *)desc + (seg & ~7);
-#endif
} else {
/* Must disable preemption while reading the GDT. */
- desc = (u32 *)&cpu_gdt_table[get_cpu()];
+ desc = (u32 *)get_cpu_gdt_table(get_cpu());
desc = (void *)desc + (seg & ~7);
}
/* Decode the code segment base from the descriptor */
- base = (desc[0] >> 16) |
- ((desc[1] & 0xff) << 16) |
- (desc[1] & 0xff000000);
+ base = get_desc_base((unsigned long *)desc);
if (seg & (1<<2)) {
-#if 1
- kunmap((void *)((unsigned long)desc & PAGE_MASK));
-#endif
up(¤t->mm->context.sem);
} else
put_cpu();
if (instr > limit)
break;
- if (__get_user(opcode, (unsigned char *) instr))
+ if (__get_user(opcode, (unsigned char __user *) instr))
break;
instr_hi = opcode & 0xf0;
scan_more = 0;
if (instr > limit)
break;
- if (__get_user(opcode, (unsigned char *) instr))
+ if (__get_user(opcode, (unsigned char __user *) instr))
break;
prefetch = (instr_lo == 0xF) &&
(opcode == 0x0D || opcode == 0x18);
return prefetch;
}
-static inline int is_prefetch(struct pt_regs *regs, unsigned long addr)
+static inline int is_prefetch(struct pt_regs *regs, unsigned long addr,
+ unsigned long error_code)
{
if (unlikely(boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
- boot_cpu_data.x86 >= 6))
+ boot_cpu_data.x86 >= 6)) {
+ /* Catch an obscure case of prefetch inside an NX page. */
+ if (nx_enabled && (error_code & 16))
+ return 0;
return __is_prefetch(regs, addr);
+ }
return 0;
}
-asmlinkage void do_invalid_op(struct pt_regs *, unsigned long);
+static noinline void force_sig_info_fault(int si_signo, int si_code,
+ unsigned long address, struct task_struct *tsk)
+{
+ siginfo_t info;
+
+ info.si_signo = si_signo;
+ info.si_errno = 0;
+ info.si_code = si_code;
+ info.si_addr = (void __user *)address;
+ force_sig_info(si_signo, &info, tsk);
+}
+
+fastcall void do_invalid_op(struct pt_regs *, unsigned long);
/*
* This routine handles page faults. It determines the address,
* bit 1 == 0 means read, 1 means write
* bit 2 == 0 means kernel, 1 means user-mode
*/
-asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code)
+fastcall 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;
unsigned long page;
- int write;
- siginfo_t info;
+ int write, si_code;
/* get the address */
- __asm__("movl %%cr2,%0":"=r" (address));
+ address = read_cr2();
+ if (notify_die(DIE_PAGE_FAULT, "page fault", regs, error_code, 14,
+ SIGSEGV) == NOTIFY_STOP)
+ return;
/* It's safe to allow irq's after cr2 has been saved */
if (regs->eflags & (X86_EFLAGS_IF|VM_MASK))
local_irq_enable();
tsk = current;
- info.si_code = SEGV_MAPERR;
+ si_code = SEGV_MAPERR;
/*
* We fault-in kernel-space virtual memory on-demand. The
* (error_code & 4) == 0, and that the fault was not a
* protection error (error_code & 1) == 0.
*/
-#ifdef CONFIG_X86_4G
- /*
- * On 4/4 all kernels faults are either bugs, vmalloc or prefetch
- */
- /* If it's vm86 fall through */
- if (unlikely(!(regs->eflags & VM_MASK) && ((regs->xcs & 3) == 0))) {
- if (error_code & 3)
- goto bad_area_nosemaphore;
- goto vmalloc_fault;
- }
-#else
if (unlikely(address >= TASK_SIZE)) {
if (!(error_code & 5))
goto vmalloc_fault;
*/
goto bad_area_nosemaphore;
}
-#endif
mm = tsk->mm;
if (in_atomic() || !mm)
goto bad_area_nosemaphore;
- down_read(&mm->mmap_sem);
+ /* 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->eip))
+ goto bad_area_nosemaphore;
+ down_read(&mm->mmap_sem);
+ }
vma = find_vma(mm, address);
if (!vma)
* we can handle it..
*/
good_area:
- info.si_code = SEGV_ACCERR;
+ si_code = SEGV_ACCERR;
write = 0;
switch (error_code & 3) {
default: /* 3: write, present */
* Valid to do another page fault here because this one came
* from user space.
*/
- if (is_prefetch(regs, address))
+ if (is_prefetch(regs, address, error_code))
return;
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 *)address;
- force_sig_info(SIGSEGV, &info, tsk);
+ force_sig_info_fault(SIGSEGV, si_code, address, tsk);
return;
}
* had been triggered by is_prefetch fixup_exception would have
* handled it.
*/
- if (is_prefetch(regs, address))
+ if (is_prefetch(regs, address, error_code))
return;
/*
bust_spinlocks(1);
#ifdef CONFIG_X86_PAE
- {
- pgd_t *pgd;
- pmd_t *pmd;
-
-
+ if (error_code & 16) {
+ pte_t *pte = lookup_address(address);
- pgd = init_mm.pgd + pgd_index(address);
- if (pgd_present(*pgd)) {
- pmd = pmd_offset(pgd, address);
- if (pmd_val(*pmd) & _PAGE_NX)
- printk(KERN_CRIT "kernel tried to access NX-protected page - exploit attempt? (uid: %d)\n", current->uid);
- }
+ if (pte && pte_present(*pte) && !pte_exec_kernel(*pte))
+ printk(KERN_CRIT "kernel tried to execute NX-protected page - exploit attempt? (uid: %d)\n", current->uid);
}
#endif
if (address < PAGE_SIZE)
printk(" at virtual address %08lx\n",address);
printk(KERN_ALERT " printing eip:\n");
printk("%08lx\n", regs->eip);
- asm("movl %%cr3,%0":"=r" (page));
+ page = read_cr3();
page = ((unsigned long *) __va(page))[address >> 22];
printk(KERN_ALERT "*pde = %08lx\n", page);
/*
printk(KERN_ALERT "*pte = %08lx\n", page);
}
#endif
+ tsk->thread.cr2 = address;
+ tsk->thread.trap_no = 14;
+ tsk->thread.error_code = error_code;
die("Oops", regs, error_code);
bust_spinlocks(0);
do_exit(SIGKILL);
goto no_context;
/* User space => ok to do another page fault */
- if (is_prefetch(regs, address))
+ if (is_prefetch(regs, address, error_code))
return;
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 *)address;
- force_sig_info(SIGBUS, &info, tsk);
+ force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk);
return;
vmalloc_fault:
* an interrupt in the middle of a task switch..
*/
int index = pgd_index(address);
+ unsigned long pgd_paddr;
pgd_t *pgd, *pgd_k;
+ pud_t *pud, *pud_k;
pmd_t *pmd, *pmd_k;
pte_t *pte_k;
- asm("movl %%cr3,%0":"=r" (pgd));
- pgd = index + (pgd_t *)__va(pgd);
+ pgd_paddr = read_cr3();
+ pgd = index + (pgd_t *)__va(pgd_paddr);
pgd_k = init_mm.pgd + index;
if (!pgd_present(*pgd_k))
/*
* set_pgd(pgd, *pgd_k); here would be useless on PAE
- * and redundant with the set_pmd() on non-PAE.
+ * and redundant with the set_pmd() on non-PAE. As would
+ * set_pud.
*/
- pmd = pmd_offset(pgd, address);
- pmd_k = pmd_offset(pgd_k, address);
+ pud = pud_offset(pgd, address);
+ pud_k = pud_offset(pgd_k, address);
+ if (!pud_present(*pud_k))
+ goto no_context;
+
+ pmd = pmd_offset(pud, address);
+ pmd_k = pmd_offset(pud_k, address);
if (!pmd_present(*pmd_k))
goto no_context;
set_pmd(pmd, *pmd_k);
git://git.onelab.eu / linux-2.6.git / blobdiff