int ret = 0;
/* kprobe_running() needs smp_processor_id() */
+#ifdef CONFIG_X86_32
+ if (!user_mode_vm(regs)) {
+#else
if (!user_mode(regs)) {
+#endif
preempt_disable();
if (kprobe_running() && kprobe_fault_handler(regs, 14))
ret = 1;
force_sig_info(si_signo, &info, tsk);
}
+#ifdef CONFIG_X86_64
static int bad_address(void *p)
{
unsigned long dummy;
return probe_kernel_address((unsigned long *)p, dummy);
}
+#endif
void dump_pagetable(unsigned long address)
{
+#ifdef CONFIG_X86_32
+ __typeof__(pte_val(__pte(0))) page;
+
+ page = read_cr3();
+ page = ((__typeof__(page) *) __va(page))[address >> PGDIR_SHIFT];
+#ifdef CONFIG_X86_PAE
+ printk("*pdpt = %016Lx ", page);
+ if ((page >> PAGE_SHIFT) < max_low_pfn
+ && page & _PAGE_PRESENT) {
+ page &= PAGE_MASK;
+ page = ((__typeof__(page) *) __va(page))[(address >> PMD_SHIFT)
+ & (PTRS_PER_PMD - 1)];
+ printk(KERN_CONT "*pde = %016Lx ", page);
+ page &= ~_PAGE_NX;
+ }
+#else
+ printk("*pde = %08lx ", page);
+#endif
+
+ /*
+ * We must not directly access the pte in the highpte
+ * case if the page table is located in highmem.
+ * And let's rather not kmap-atomic the pte, just in case
+ * it's allocated already.
+ */
+ if ((page >> PAGE_SHIFT) < max_low_pfn
+ && (page & _PAGE_PRESENT)
+ && !(page & _PAGE_PSE)) {
+ page &= PAGE_MASK;
+ page = ((__typeof__(page) *) __va(page))[(address >> PAGE_SHIFT)
+ & (PTRS_PER_PTE - 1)];
+ printk("*pte = %0*Lx ", sizeof(page)*2, (u64)page);
+ }
+
+ printk("\n");
+#else /* CONFIG_X86_64 */
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
return;
bad:
printk("BAD\n");
+#endif
+}
+
+#ifdef CONFIG_X86_32
+static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address)
+{
+ unsigned index = pgd_index(address);
+ pgd_t *pgd_k;
+ pud_t *pud, *pud_k;
+ pmd_t *pmd, *pmd_k;
+
+ pgd += index;
+ pgd_k = init_mm.pgd + index;
+
+ if (!pgd_present(*pgd_k))
+ return NULL;
+
+ /*
+ * set_pgd(pgd, *pgd_k); here would be useless on PAE
+ * and redundant with the set_pmd() on non-PAE. As would
+ * set_pud.
+ */
+
+ pud = pud_offset(pgd, address);
+ pud_k = pud_offset(pgd_k, address);
+ if (!pud_present(*pud_k))
+ return NULL;
+
+ pmd = pmd_offset(pud, address);
+ pmd_k = pmd_offset(pud_k, address);
+ if (!pmd_present(*pmd_k))
+ return NULL;
+ if (!pmd_present(*pmd)) {
+ set_pmd(pmd, *pmd_k);
+ arch_flush_lazy_mmu_mode();
+ } else
+ BUG_ON(pmd_page(*pmd) != pmd_page(*pmd_k));
+ return pmd_k;
}
+#endif
#ifdef CONFIG_X86_64
static const char errata93_warning[] =
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";
+#endif
/* Workaround for K8 erratum #93 & buggy BIOS.
BIOS SMM functions are required to use a specific workaround
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. */
-
+ Note we only handle faults in kernel here.
+ Does nothing for X86_32
+ */
static int is_errata93(struct pt_regs *regs, unsigned long address)
{
+#ifdef CONFIG_X86_64
static int warned;
if (address != regs->ip)
return 0;
regs->ip = address;
return 1;
}
+#endif
return 0;
}
+
+/*
+ * Work around K8 erratum #100 K8 in compat mode occasionally jumps to illegal
+ * addresses >4GB. We catch this 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.
+ */
+static int is_errata100(struct pt_regs *regs, unsigned long address)
+{
+#ifdef CONFIG_X86_64
+ if ((regs->cs == __USER32_CS || (regs->cs & (1<<2))) &&
+ (address >> 32))
+ return 1;
#endif
+ return 0;
+}
+
+void do_invalid_op(struct pt_regs *, unsigned long);
+static int is_f00f_bug(struct pt_regs *regs, unsigned long address)
+{
+#ifdef CONFIG_X86_F00F_BUG
+ unsigned long nr;
+ /*
+ * Pentium F0 0F C7 C8 bug workaround.
+ */
+ if (boot_cpu_data.f00f_bug) {
+ nr = (address - idt_descr.address) >> 3;
+
+ if (nr == 6) {
+ do_invalid_op(regs, 0);
+ return 1;
+ }
+ }
+#endif
+ return 0;
+}
+
+static void show_fault_oops(struct pt_regs *regs, unsigned long error_code,
+ unsigned long address)
+{
+#ifdef CONFIG_X86_32
+ if (!oops_may_print())
+ return;
+
+#ifdef CONFIG_X86_PAE
+ if (error_code & PF_INSTR) {
+ int level;
+ pte_t *pte = lookup_address(address, &level);
+
+ if (pte && pte_present(*pte) && !pte_exec(*pte))
+ printk(KERN_CRIT "kernel tried to execute "
+ "NX-protected page - exploit attempt? "
+ "(uid: %d)\n", current->uid);
+ }
+#endif
+ printk(KERN_ALERT "BUG: unable to handle kernel ");
+ if (address < PAGE_SIZE)
+ printk(KERN_CONT "NULL pointer dereference");
+ else
+ printk(KERN_CONT "paging request");
+ printk(KERN_CONT " at %08lx\n", address);
+
+ printk(KERN_ALERT "IP:");
+ printk_address(regs->ip, 1);
+ dump_pagetable(address);
+#else /* CONFIG_X86_64 */
+ printk(KERN_ALERT "BUG: unable to handle kernel ");
+ if (address < PAGE_SIZE)
+ printk(KERN_CONT "NULL pointer dereference");
+ else
+ printk(KERN_CONT "paging request");
+ printk(KERN_CONT " at %016lx\n", address);
+
+ printk(KERN_ALERT "IP:");
+ printk_address(regs->ip, 1);
+ dump_pagetable(address);
+#endif
+}
+
+#ifdef CONFIG_X86_64
static noinline void pgtable_bad(unsigned long address, struct pt_regs *regs,
unsigned long error_code)
{
regs = NULL;
oops_end(flags, regs, SIGKILL);
}
+#endif
/*
+ * X86_32
+ * Handle a fault on the vmalloc or module mapping area
+ *
+ * X86_64
* Handle a fault on the vmalloc area
*
* This assumes no large pages in there.
*/
static int vmalloc_fault(unsigned long address)
{
+#ifdef CONFIG_X86_32
+ unsigned long pgd_paddr;
+ pmd_t *pmd_k;
+ pte_t *pte_k;
+ /*
+ * Synchronize this task's top level page-table
+ * with the 'reference' page table.
+ *
+ * Do _not_ use "current" here. We might be inside
+ * an interrupt in the middle of a task switch..
+ */
+ pgd_paddr = read_cr3();
+ pmd_k = vmalloc_sync_one(__va(pgd_paddr), address);
+ if (!pmd_k)
+ return -1;
+ pte_k = pte_offset_kernel(pmd_k, address);
+ if (!pte_present(*pte_k))
+ return -1;
+ return 0;
+#else
pgd_t *pgd, *pgd_ref;
pud_t *pud, *pud_ref;
pmd_t *pmd, *pmd_ref;
if (!pte_present(*pte) || pte_pfn(*pte) != pte_pfn(*pte_ref))
BUG();
return 0;
+#endif
}
int show_unhandled_signals = 1;
* 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)
+#ifdef CONFIG_X86_64
+asmlinkage
+#endif
+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;
- int write, fault;
+ int write, si_code;
+ int fault;
+#ifdef CONFIG_X86_64
unsigned long flags;
- int si_code;
+#endif
/*
* We can fault from pretty much anywhere, with unknown IRQ state.
* (error_code & 4) == 0, and that the fault was not a
* protection error (error_code & 9) == 0.
*/
+#ifdef CONFIG_X86_32
+ if (unlikely(address >= TASK_SIZE)) {
+ if (!(error_code & (PF_RSVD|PF_USER|PF_PROT)) &&
+ vmalloc_fault(address) >= 0)
+ return;
+ /*
+ * Don't take the mm semaphore here. If we fixup a prefetch
+ * fault we could otherwise deadlock.
+ */
+ goto bad_area_nosemaphore;
+ }
+
+ /* It's safe to allow irq's after cr2 has been saved and the vmalloc
+ fault has been handled. */
+ if (regs->flags & (X86_EFLAGS_IF|VM_MASK))
+ local_irq_enable();
+
+ /*
+ * If we're in an interrupt, have no user context or are running in an
+ * atomic region then we must not take the fault.
+ */
+ if (in_atomic() || !mm)
+ goto bad_area_nosemaphore;
+#else /* CONFIG_X86_64 */
if (unlikely(address >= TASK_SIZE64)) {
/*
* Don't check for the module range here: its PML4
*/
goto bad_area_nosemaphore;
}
-
if (likely(regs->flags & X86_EFLAGS_IF))
local_irq_enable();
*/
if (user_mode_vm(regs))
error_code |= PF_USER;
-
- again:
+again:
+#endif
/* 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
vma = find_vma(mm, address);
if (!vma)
goto bad_area;
+#ifdef CONFIG_X86_32
+ if (vma->vm_start <= address)
+#else
if (likely(vma->vm_start <= address))
+#endif
goto good_area;
if (!(vma->vm_flags & VM_GROWSDOWN))
goto bad_area;
if (error_code & PF_USER) {
- /* Allow userspace just enough access below the stack pointer
- * to let the 'enter' instruction work.
+ /*
+ * Accessing the stack below %sp is always a bug.
+ * The large cushion allows instructions like enter
+ * and pusha to work. ("enter $65535,$31" pushes
+ * 32 pointers and then decrements %sp by 65535.)
*/
if (address + 65536 + 32 * sizeof(unsigned long) < regs->sp)
goto bad_area;
goto bad_area;
}
+#ifdef CONFIG_X86_32
+survive:
+#endif
/*
* If for any reason at all we couldn't handle the fault,
* make sure we exit gracefully rather than endlessly redo
tsk->maj_flt++;
else
tsk->min_flt++;
+
+#ifdef CONFIG_X86_32
+ /*
+ * Did it hit the DOS screen memory VA from vm86 mode?
+ */
+ if (v8086_mode(regs)) {
+ unsigned long bit = (address - 0xA0000) >> PAGE_SHIFT;
+ if (bit < 32)
+ tsk->thread.screen_bitmap |= 1 << bit;
+ }
+#endif
up_read(&mm->mmap_sem);
return;
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();
+ /*
+ * Valid to do another page fault here because this one came
+ * from user space.
+ */
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))
+ if (is_errata100(regs, address))
return;
if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
printk_ratelimit()) {
printk(
- "%s%s[%d]: segfault at %lx ip %lx sp %lx error %lx\n",
- tsk->pid > 1 ? KERN_INFO : KERN_EMERG,
- tsk->comm, tsk->pid, address, regs->ip,
- regs->sp, error_code);
+#ifdef CONFIG_X86_32
+ "%s%s[%d]: segfault at %lx ip %08lx sp %08lx error %lx",
+#else
+ "%s%s[%d]: segfault at %lx ip %lx sp %lx error %lx",
+#endif
+ task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG,
+ tsk->comm, task_pid_nr(tsk), address, regs->ip,
+ regs->sp, error_code);
+ print_vma_addr(" in ", regs->ip);
+ printk("\n");
}
tsk->thread.cr2 = address;
/* Kernel addresses are always protection faults */
tsk->thread.error_code = error_code | (address >= TASK_SIZE);
tsk->thread.trap_no = 14;
-
force_sig_info_fault(SIGSEGV, si_code, address, tsk);
return;
}
+ if (is_f00f_bug(regs, address))
+ return;
+
no_context:
/* Are we prepared to handle this kernel fault? */
if (fixup_exception(regs))
return;
/*
+ * X86_32
+ * Valid to do another page fault here, because if this fault
+ * had been triggered by is_prefetch fixup_exception would have
+ * handled it.
+ *
+ * X86_64
* Hall of shame of CPU/BIOS bugs.
*/
-
if (is_prefetch(regs, address, error_code))
return;
* Oops. The kernel tried to access some bad page. We'll have to
* terminate things with extreme prejudice.
*/
+#ifdef CONFIG_X86_32
+ bust_spinlocks(1);
+ show_fault_oops(regs, error_code, address);
+
+ 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);
+#else /* CONFIG_X86_64 */
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->ip, regs->bp);
- dump_pagetable(address);
+ show_fault_oops(regs, error_code, address);
+
tsk->thread.cr2 = address;
tsk->thread.trap_no = 14;
tsk->thread.error_code = error_code;
/* Executive summary in case the body of the oops scrolled away */
printk(KERN_EMERG "CR2: %016lx\n", address);
oops_end(flags, regs, SIGKILL);
+#endif
/*
* We ran out of memory, or some other thing happened to us that made
*/
out_of_memory:
up_read(&mm->mmap_sem);
+#ifdef CONFIG_X86_32
+ if (is_global_init(tsk)) {
+ yield();
+ down_read(&mm->mmap_sem);
+ goto survive;
+ }
+#else
if (is_global_init(current)) {
yield();
goto again;
}
+#endif
printk("VM: killing process %s\n", tsk->comm);
if (error_code & PF_USER)
do_group_exit(SIGKILL);
/* Kernel mode? Handle exceptions or die */
if (!(error_code & PF_USER))
goto no_context;
-
+#ifdef CONFIG_X86_32
+ /* User space => ok to do another page fault */
+ if (is_prefetch(regs, address, error_code))
+ return;
+#endif
tsk->thread.cr2 = address;
tsk->thread.error_code = error_code;
tsk->thread.trap_no = 14;
force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk);
- return;
}
+#ifdef CONFIG_X86_64
DEFINE_SPINLOCK(pgd_lock);
LIST_HEAD(pgd_list);
+#endif
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). */
+#ifdef CONFIG_X86_32
+ /*
+ * 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 = TASK_SIZE;
+ unsigned long address;
+
+ if (SHARED_KERNEL_PMD)
+ return;
+
+ BUILD_BUG_ON(TASK_SIZE & ~PGDIR_MASK);
+ for (address = start; address >= TASK_SIZE; address += PGDIR_SIZE) {
+ if (!test_bit(pgd_index(address), insync)) {
+ unsigned long flags;
+ struct page *page;
+
+ spin_lock_irqsave(&pgd_lock, flags);
+ for (page = pgd_list; page; page =
+ (struct page *)page->index)
+ if (!vmalloc_sync_one(page_address(page),
+ address)) {
+ BUG_ON(page != pgd_list);
+ break;
+ }
+ spin_unlock_irqrestore(&pgd_lock, flags);
+ if (!page)
+ set_bit(pgd_index(address), insync);
+ }
+ if (address == start && test_bit(pgd_index(address), insync))
+ start = address + PGDIR_SIZE;
+ }
+#else /* CONFIG_X86_64 */
+ /*
+ * 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;
BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
(__START_KERNEL & PGDIR_MASK)));
+#endif
}
projects / karo-tx-linux.git / blobdiff