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Diffstat (limited to 'arch/x86/mm/fault_64.c')
-rw-r--r--arch/x86/mm/fault_64.c148
1 files changed, 147 insertions, 1 deletions
diff --git a/arch/x86/mm/fault_64.c b/arch/x86/mm/fault_64.c
index e12c34ba4ba..edca689c62d 100644
--- a/arch/x86/mm/fault_64.c
+++ b/arch/x86/mm/fault_64.c
@@ -176,14 +176,52 @@ static void force_sig_info_fault(int si_signo, int si_code,
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;
@@ -215,7 +253,46 @@ ret:
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[] =
@@ -296,6 +373,32 @@ static int is_f00f_bug(struct pt_regs *regs, unsigned long address)
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");
@@ -306,8 +409,10 @@ static void show_fault_oops(struct pt_regs *regs, unsigned long error_code,
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)
{
@@ -325,6 +430,7 @@ static noinline void pgtable_bad(unsigned long address, struct pt_regs *regs,
regs = NULL;
oops_end(flags, regs, SIGKILL);
}
+#endif
/*
* Handle a fault on the vmalloc area
@@ -590,12 +696,15 @@ bad_area:
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;
@@ -696,6 +805,42 @@ LIST_HEAD(pgd_list);
void vmalloc_sync_all(void)
{
+#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
@@ -732,4 +877,5 @@ void vmalloc_sync_all(void)
BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
(__START_KERNEL & PGDIR_MASK)));
+#endif
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-09-11 19:16:17 +0000