Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2 | * Copyright (C) 1995 Linus Torvalds |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 3 | * Copyright (C) 2001, 2002 Andi Kleen, SuSE Labs. |
Ingo Molnar | f8eeb2e | 2009-02-20 23:13:36 +0100 | [diff] [blame] | 4 | * Copyright (C) 2008-2009, Red Hat Inc., Ingo Molnar |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5 | */ |
Ingo Molnar | a2bcd47 | 2009-03-29 23:47:48 +0200 | [diff] [blame] | 6 | #include <linux/magic.h> /* STACK_END_MAGIC */ |
| 7 | #include <linux/sched.h> /* test_thread_flag(), ... */ |
| 8 | #include <linux/kdebug.h> /* oops_begin/end, ... */ |
| 9 | #include <linux/module.h> /* search_exception_table */ |
| 10 | #include <linux/bootmem.h> /* max_low_pfn */ |
| 11 | #include <linux/kprobes.h> /* __kprobes, ... */ |
| 12 | #include <linux/mmiotrace.h> /* kmmio_handler, ... */ |
Ingo Molnar | cdd6c48 | 2009-09-21 12:02:48 +0200 | [diff] [blame] | 13 | #include <linux/perf_event.h> /* perf_sw_event */ |
Andi Kleen | f672b49 | 2010-09-27 22:05:55 +0200 | [diff] [blame] | 14 | #include <linux/hugetlb.h> /* hstate_index_to_shift */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 15 | |
Ingo Molnar | a2bcd47 | 2009-03-29 23:47:48 +0200 | [diff] [blame] | 16 | #include <asm/traps.h> /* dotraplinkage, ... */ |
| 17 | #include <asm/pgalloc.h> /* pgd_*(), ... */ |
Vegard Nossum | f856129 | 2008-04-04 00:53:23 +0200 | [diff] [blame] | 18 | #include <asm/kmemcheck.h> /* kmemcheck_*(), ... */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 19 | |
Harvey Harrison | 33cb524 | 2008-01-30 13:32:19 +0100 | [diff] [blame] | 20 | /* |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 21 | * Page fault error code bits: |
| 22 | * |
| 23 | * bit 0 == 0: no page found 1: protection fault |
| 24 | * bit 1 == 0: read access 1: write access |
| 25 | * bit 2 == 0: kernel-mode access 1: user-mode access |
| 26 | * bit 3 == 1: use of reserved bit detected |
| 27 | * bit 4 == 1: fault was an instruction fetch |
Harvey Harrison | 33cb524 | 2008-01-30 13:32:19 +0100 | [diff] [blame] | 28 | */ |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 29 | enum x86_pf_error_code { |
| 30 | |
| 31 | PF_PROT = 1 << 0, |
| 32 | PF_WRITE = 1 << 1, |
| 33 | PF_USER = 1 << 2, |
| 34 | PF_RSVD = 1 << 3, |
| 35 | PF_INSTR = 1 << 4, |
| 36 | }; |
Andi Kleen | 66c5815 | 2006-01-11 22:44:09 +0100 | [diff] [blame] | 37 | |
Ingo Molnar | b814d41 | 2009-02-20 22:32:10 +0100 | [diff] [blame] | 38 | /* |
Ingo Molnar | b319eed | 2009-02-22 10:24:18 +0100 | [diff] [blame] | 39 | * Returns 0 if mmiotrace is disabled, or if the fault is not |
| 40 | * handled by mmiotrace: |
Ingo Molnar | b814d41 | 2009-02-20 22:32:10 +0100 | [diff] [blame] | 41 | */ |
Masami Hiramatsu | 62c9295 | 2009-08-27 13:23:11 -0400 | [diff] [blame] | 42 | static inline int __kprobes |
| 43 | kmmio_fault(struct pt_regs *regs, unsigned long addr) |
Pekka Paalanen | 8606978 | 2008-05-12 21:20:56 +0200 | [diff] [blame] | 44 | { |
Pekka Paalanen | 0fd0e3d | 2008-05-12 21:20:57 +0200 | [diff] [blame] | 45 | if (unlikely(is_kmmio_active())) |
| 46 | if (kmmio_handler(regs, addr) == 1) |
| 47 | return -1; |
Pekka Paalanen | 0fd0e3d | 2008-05-12 21:20:57 +0200 | [diff] [blame] | 48 | return 0; |
Pekka Paalanen | 8606978 | 2008-05-12 21:20:56 +0200 | [diff] [blame] | 49 | } |
| 50 | |
Masami Hiramatsu | 62c9295 | 2009-08-27 13:23:11 -0400 | [diff] [blame] | 51 | static inline int __kprobes notify_page_fault(struct pt_regs *regs) |
Anil S Keshavamurthy | 1bd858a | 2006-06-26 00:25:25 -0700 | [diff] [blame] | 52 | { |
Christoph Hellwig | 74a0b57 | 2007-10-16 01:24:07 -0700 | [diff] [blame] | 53 | int ret = 0; |
Anil S Keshavamurthy | 1bd858a | 2006-06-26 00:25:25 -0700 | [diff] [blame] | 54 | |
Christoph Hellwig | 74a0b57 | 2007-10-16 01:24:07 -0700 | [diff] [blame] | 55 | /* kprobe_running() needs smp_processor_id() */ |
Ingo Molnar | b180181 | 2009-02-20 22:42:57 +0100 | [diff] [blame] | 56 | if (kprobes_built_in() && !user_mode_vm(regs)) { |
Christoph Hellwig | 74a0b57 | 2007-10-16 01:24:07 -0700 | [diff] [blame] | 57 | preempt_disable(); |
| 58 | if (kprobe_running() && kprobe_fault_handler(regs, 14)) |
| 59 | ret = 1; |
| 60 | preempt_enable(); |
| 61 | } |
Anil S Keshavamurthy | 1bd858a | 2006-06-26 00:25:25 -0700 | [diff] [blame] | 62 | |
Christoph Hellwig | 74a0b57 | 2007-10-16 01:24:07 -0700 | [diff] [blame] | 63 | return ret; |
Harvey Harrison | 33cb524 | 2008-01-30 13:32:19 +0100 | [diff] [blame] | 64 | } |
Anil S Keshavamurthy | 1bd858a | 2006-06-26 00:25:25 -0700 | [diff] [blame] | 65 | |
Harvey Harrison | 1dc85be | 2008-01-30 13:32:35 +0100 | [diff] [blame] | 66 | /* |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 67 | * Prefetch quirks: |
Harvey Harrison | 1dc85be | 2008-01-30 13:32:35 +0100 | [diff] [blame] | 68 | * |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 69 | * 32-bit mode: |
Harvey Harrison | 1dc85be | 2008-01-30 13:32:35 +0100 | [diff] [blame] | 70 | * |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 71 | * Sometimes AMD Athlon/Opteron CPUs report invalid exceptions on prefetch. |
| 72 | * Check that here and ignore it. |
| 73 | * |
| 74 | * 64-bit mode: |
| 75 | * |
| 76 | * Sometimes the CPU reports invalid exceptions on prefetch. |
| 77 | * Check that here and ignore it. |
| 78 | * |
| 79 | * Opcode checker based on code by Richard Brunner. |
Harvey Harrison | 1dc85be | 2008-01-30 13:32:35 +0100 | [diff] [blame] | 80 | */ |
Ingo Molnar | 107a036 | 2009-02-20 20:37:05 +0100 | [diff] [blame] | 81 | static inline int |
| 82 | check_prefetch_opcode(struct pt_regs *regs, unsigned char *instr, |
| 83 | unsigned char opcode, int *prefetch) |
| 84 | { |
| 85 | unsigned char instr_hi = opcode & 0xf0; |
| 86 | unsigned char instr_lo = opcode & 0x0f; |
| 87 | |
| 88 | switch (instr_hi) { |
| 89 | case 0x20: |
| 90 | case 0x30: |
| 91 | /* |
| 92 | * Values 0x26,0x2E,0x36,0x3E are valid x86 prefixes. |
| 93 | * In X86_64 long mode, the CPU will signal invalid |
| 94 | * opcode if some of these prefixes are present so |
| 95 | * X86_64 will never get here anyway |
| 96 | */ |
| 97 | return ((instr_lo & 7) == 0x6); |
| 98 | #ifdef CONFIG_X86_64 |
| 99 | case 0x40: |
| 100 | /* |
| 101 | * In AMD64 long mode 0x40..0x4F are valid REX prefixes |
| 102 | * Need to figure out under what instruction mode the |
| 103 | * instruction was issued. Could check the LDT for lm, |
| 104 | * but for now it's good enough to assume that long |
| 105 | * mode only uses well known segments or kernel. |
| 106 | */ |
| 107 | return (!user_mode(regs)) || (regs->cs == __USER_CS); |
| 108 | #endif |
| 109 | case 0x60: |
| 110 | /* 0x64 thru 0x67 are valid prefixes in all modes. */ |
| 111 | return (instr_lo & 0xC) == 0x4; |
| 112 | case 0xF0: |
| 113 | /* 0xF0, 0xF2, 0xF3 are valid prefixes in all modes. */ |
| 114 | return !instr_lo || (instr_lo>>1) == 1; |
| 115 | case 0x00: |
| 116 | /* Prefetch instruction is 0x0F0D or 0x0F18 */ |
| 117 | if (probe_kernel_address(instr, opcode)) |
| 118 | return 0; |
| 119 | |
| 120 | *prefetch = (instr_lo == 0xF) && |
| 121 | (opcode == 0x0D || opcode == 0x18); |
| 122 | return 0; |
| 123 | default: |
| 124 | return 0; |
| 125 | } |
| 126 | } |
| 127 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 128 | static int |
| 129 | is_prefetch(struct pt_regs *regs, unsigned long error_code, unsigned long addr) |
Harvey Harrison | 33cb524 | 2008-01-30 13:32:19 +0100 | [diff] [blame] | 130 | { |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 131 | unsigned char *max_instr; |
Andi Kleen | ab2bf0c | 2006-12-07 02:14:06 +0100 | [diff] [blame] | 132 | unsigned char *instr; |
Harvey Harrison | 33cb524 | 2008-01-30 13:32:19 +0100 | [diff] [blame] | 133 | int prefetch = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 134 | |
Ingo Molnar | 3085354 | 2008-03-27 21:29:09 +0100 | [diff] [blame] | 135 | /* |
| 136 | * If it was a exec (instruction fetch) fault on NX page, then |
| 137 | * do not ignore the fault: |
| 138 | */ |
Andi Kleen | 66c5815 | 2006-01-11 22:44:09 +0100 | [diff] [blame] | 139 | if (error_code & PF_INSTR) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 140 | return 0; |
Harvey Harrison | 1dc85be | 2008-01-30 13:32:35 +0100 | [diff] [blame] | 141 | |
Ingo Molnar | 107a036 | 2009-02-20 20:37:05 +0100 | [diff] [blame] | 142 | instr = (void *)convert_ip_to_linear(current, regs); |
Andi Kleen | f1290ec | 2005-04-16 15:24:59 -0700 | [diff] [blame] | 143 | max_instr = instr + 15; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 144 | |
Vincent Hanquez | 76381fe | 2005-06-23 00:08:46 -0700 | [diff] [blame] | 145 | if (user_mode(regs) && instr >= (unsigned char *)TASK_SIZE) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 146 | return 0; |
| 147 | |
Ingo Molnar | 107a036 | 2009-02-20 20:37:05 +0100 | [diff] [blame] | 148 | while (instr < max_instr) { |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 149 | unsigned char opcode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 150 | |
Andi Kleen | ab2bf0c | 2006-12-07 02:14:06 +0100 | [diff] [blame] | 151 | if (probe_kernel_address(instr, opcode)) |
Harvey Harrison | 33cb524 | 2008-01-30 13:32:19 +0100 | [diff] [blame] | 152 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 153 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 154 | instr++; |
| 155 | |
Ingo Molnar | 107a036 | 2009-02-20 20:37:05 +0100 | [diff] [blame] | 156 | if (!check_prefetch_opcode(regs, instr, opcode, &prefetch)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 157 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 158 | } |
| 159 | return prefetch; |
| 160 | } |
| 161 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 162 | static void |
| 163 | force_sig_info_fault(int si_signo, int si_code, unsigned long address, |
Andi Kleen | f672b49 | 2010-09-27 22:05:55 +0200 | [diff] [blame] | 164 | struct task_struct *tsk, int fault) |
Harvey Harrison | c4aba4a | 2008-01-30 13:32:35 +0100 | [diff] [blame] | 165 | { |
Andi Kleen | f672b49 | 2010-09-27 22:05:55 +0200 | [diff] [blame] | 166 | unsigned lsb = 0; |
Harvey Harrison | c4aba4a | 2008-01-30 13:32:35 +0100 | [diff] [blame] | 167 | siginfo_t info; |
| 168 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 169 | info.si_signo = si_signo; |
| 170 | info.si_errno = 0; |
| 171 | info.si_code = si_code; |
| 172 | info.si_addr = (void __user *)address; |
Andi Kleen | f672b49 | 2010-09-27 22:05:55 +0200 | [diff] [blame] | 173 | if (fault & VM_FAULT_HWPOISON_LARGE) |
| 174 | lsb = hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault)); |
| 175 | if (fault & VM_FAULT_HWPOISON) |
| 176 | lsb = PAGE_SHIFT; |
| 177 | info.si_addr_lsb = lsb; |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 178 | |
Harvey Harrison | c4aba4a | 2008-01-30 13:32:35 +0100 | [diff] [blame] | 179 | force_sig_info(si_signo, &info, tsk); |
| 180 | } |
| 181 | |
Ingo Molnar | f2f13a8 | 2009-02-20 22:50:24 +0100 | [diff] [blame] | 182 | DEFINE_SPINLOCK(pgd_lock); |
| 183 | LIST_HEAD(pgd_list); |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 184 | |
Ingo Molnar | f2f13a8 | 2009-02-20 22:50:24 +0100 | [diff] [blame] | 185 | #ifdef CONFIG_X86_32 |
| 186 | static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address) |
| 187 | { |
| 188 | unsigned index = pgd_index(address); |
| 189 | pgd_t *pgd_k; |
| 190 | pud_t *pud, *pud_k; |
| 191 | pmd_t *pmd, *pmd_k; |
| 192 | |
| 193 | pgd += index; |
| 194 | pgd_k = init_mm.pgd + index; |
| 195 | |
| 196 | if (!pgd_present(*pgd_k)) |
| 197 | return NULL; |
| 198 | |
| 199 | /* |
| 200 | * set_pgd(pgd, *pgd_k); here would be useless on PAE |
| 201 | * and redundant with the set_pmd() on non-PAE. As would |
| 202 | * set_pud. |
| 203 | */ |
| 204 | pud = pud_offset(pgd, address); |
| 205 | pud_k = pud_offset(pgd_k, address); |
| 206 | if (!pud_present(*pud_k)) |
| 207 | return NULL; |
| 208 | |
| 209 | pmd = pmd_offset(pud, address); |
| 210 | pmd_k = pmd_offset(pud_k, address); |
| 211 | if (!pmd_present(*pmd_k)) |
| 212 | return NULL; |
| 213 | |
Jeremy Fitzhardinge | b8bcfe9 | 2009-02-17 23:05:19 -0800 | [diff] [blame] | 214 | if (!pmd_present(*pmd)) |
Ingo Molnar | f2f13a8 | 2009-02-20 22:50:24 +0100 | [diff] [blame] | 215 | set_pmd(pmd, *pmd_k); |
Jeremy Fitzhardinge | b8bcfe9 | 2009-02-17 23:05:19 -0800 | [diff] [blame] | 216 | else |
Ingo Molnar | f2f13a8 | 2009-02-20 22:50:24 +0100 | [diff] [blame] | 217 | BUG_ON(pmd_page(*pmd) != pmd_page(*pmd_k)); |
Ingo Molnar | f2f13a8 | 2009-02-20 22:50:24 +0100 | [diff] [blame] | 218 | |
| 219 | return pmd_k; |
Harvey Harrison | 33cb524 | 2008-01-30 13:32:19 +0100 | [diff] [blame] | 220 | } |
Ingo Molnar | f2f13a8 | 2009-02-20 22:50:24 +0100 | [diff] [blame] | 221 | |
| 222 | void vmalloc_sync_all(void) |
| 223 | { |
| 224 | unsigned long address; |
| 225 | |
| 226 | if (SHARED_KERNEL_PMD) |
| 227 | return; |
| 228 | |
| 229 | for (address = VMALLOC_START & PMD_MASK; |
| 230 | address >= TASK_SIZE && address < FIXADDR_TOP; |
| 231 | address += PMD_SIZE) { |
Ingo Molnar | f2f13a8 | 2009-02-20 22:50:24 +0100 | [diff] [blame] | 232 | struct page *page; |
| 233 | |
Andrea Arcangeli | a79e53d | 2011-02-16 15:45:22 -0800 | [diff] [blame] | 234 | spin_lock(&pgd_lock); |
Ingo Molnar | f2f13a8 | 2009-02-20 22:50:24 +0100 | [diff] [blame] | 235 | list_for_each_entry(page, &pgd_list, lru) { |
Jeremy Fitzhardinge | 617d34d | 2010-09-21 12:01:51 -0700 | [diff] [blame] | 236 | spinlock_t *pgt_lock; |
Borislav Petkov | f01f7c5 | 2010-10-19 22:17:37 +0000 | [diff] [blame] | 237 | pmd_t *ret; |
Jeremy Fitzhardinge | 617d34d | 2010-09-21 12:01:51 -0700 | [diff] [blame] | 238 | |
Andrea Arcangeli | a79e53d | 2011-02-16 15:45:22 -0800 | [diff] [blame] | 239 | /* the pgt_lock only for Xen */ |
Jeremy Fitzhardinge | 617d34d | 2010-09-21 12:01:51 -0700 | [diff] [blame] | 240 | pgt_lock = &pgd_page_get_mm(page)->page_table_lock; |
| 241 | |
| 242 | spin_lock(pgt_lock); |
| 243 | ret = vmalloc_sync_one(page_address(page), address); |
| 244 | spin_unlock(pgt_lock); |
| 245 | |
| 246 | if (!ret) |
Ingo Molnar | f2f13a8 | 2009-02-20 22:50:24 +0100 | [diff] [blame] | 247 | break; |
| 248 | } |
Andrea Arcangeli | a79e53d | 2011-02-16 15:45:22 -0800 | [diff] [blame] | 249 | spin_unlock(&pgd_lock); |
Ingo Molnar | f2f13a8 | 2009-02-20 22:50:24 +0100 | [diff] [blame] | 250 | } |
| 251 | } |
| 252 | |
| 253 | /* |
| 254 | * 32-bit: |
| 255 | * |
| 256 | * Handle a fault on the vmalloc or module mapping area |
| 257 | */ |
Masami Hiramatsu | 62c9295 | 2009-08-27 13:23:11 -0400 | [diff] [blame] | 258 | static noinline __kprobes int vmalloc_fault(unsigned long address) |
Ingo Molnar | f2f13a8 | 2009-02-20 22:50:24 +0100 | [diff] [blame] | 259 | { |
| 260 | unsigned long pgd_paddr; |
| 261 | pmd_t *pmd_k; |
| 262 | pte_t *pte_k; |
| 263 | |
| 264 | /* Make sure we are in vmalloc area: */ |
| 265 | if (!(address >= VMALLOC_START && address < VMALLOC_END)) |
| 266 | return -1; |
| 267 | |
Frederic Weisbecker | ebc8827 | 2010-09-27 18:50:51 +0200 | [diff] [blame] | 268 | WARN_ON_ONCE(in_nmi()); |
| 269 | |
Ingo Molnar | f2f13a8 | 2009-02-20 22:50:24 +0100 | [diff] [blame] | 270 | /* |
| 271 | * Synchronize this task's top level page-table |
| 272 | * with the 'reference' page table. |
| 273 | * |
| 274 | * Do _not_ use "current" here. We might be inside |
| 275 | * an interrupt in the middle of a task switch.. |
| 276 | */ |
| 277 | pgd_paddr = read_cr3(); |
| 278 | pmd_k = vmalloc_sync_one(__va(pgd_paddr), address); |
| 279 | if (!pmd_k) |
| 280 | return -1; |
| 281 | |
| 282 | pte_k = pte_offset_kernel(pmd_k, address); |
| 283 | if (!pte_present(*pte_k)) |
| 284 | return -1; |
| 285 | |
| 286 | return 0; |
| 287 | } |
| 288 | |
| 289 | /* |
| 290 | * Did it hit the DOS screen memory VA from vm86 mode? |
| 291 | */ |
| 292 | static inline void |
| 293 | check_v8086_mode(struct pt_regs *regs, unsigned long address, |
| 294 | struct task_struct *tsk) |
| 295 | { |
| 296 | unsigned long bit; |
| 297 | |
| 298 | if (!v8086_mode(regs)) |
| 299 | return; |
| 300 | |
| 301 | bit = (address - 0xA0000) >> PAGE_SHIFT; |
| 302 | if (bit < 32) |
| 303 | tsk->thread.screen_bitmap |= 1 << bit; |
| 304 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 305 | |
Akinobu Mita | 087975b | 2009-06-27 15:35:15 +0900 | [diff] [blame] | 306 | static bool low_pfn(unsigned long pfn) |
| 307 | { |
| 308 | return pfn < max_low_pfn; |
| 309 | } |
| 310 | |
Adrian Bunk | cae30f8 | 2008-02-13 23:31:31 +0200 | [diff] [blame] | 311 | static void dump_pagetable(unsigned long address) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 312 | { |
Akinobu Mita | 087975b | 2009-06-27 15:35:15 +0900 | [diff] [blame] | 313 | pgd_t *base = __va(read_cr3()); |
| 314 | pgd_t *pgd = &base[pgd_index(address)]; |
| 315 | pmd_t *pmd; |
| 316 | pte_t *pte; |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 317 | |
Harvey Harrison | 1156e09 | 2008-01-30 13:34:10 +0100 | [diff] [blame] | 318 | #ifdef CONFIG_X86_PAE |
Akinobu Mita | 087975b | 2009-06-27 15:35:15 +0900 | [diff] [blame] | 319 | printk("*pdpt = %016Lx ", pgd_val(*pgd)); |
| 320 | if (!low_pfn(pgd_val(*pgd) >> PAGE_SHIFT) || !pgd_present(*pgd)) |
| 321 | goto out; |
Harvey Harrison | 1156e09 | 2008-01-30 13:34:10 +0100 | [diff] [blame] | 322 | #endif |
Akinobu Mita | 087975b | 2009-06-27 15:35:15 +0900 | [diff] [blame] | 323 | pmd = pmd_offset(pud_offset(pgd, address), address); |
| 324 | printk(KERN_CONT "*pde = %0*Lx ", sizeof(*pmd) * 2, (u64)pmd_val(*pmd)); |
Harvey Harrison | 1156e09 | 2008-01-30 13:34:10 +0100 | [diff] [blame] | 325 | |
| 326 | /* |
| 327 | * We must not directly access the pte in the highpte |
| 328 | * case if the page table is located in highmem. |
| 329 | * And let's rather not kmap-atomic the pte, just in case |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 330 | * it's allocated already: |
Harvey Harrison | 1156e09 | 2008-01-30 13:34:10 +0100 | [diff] [blame] | 331 | */ |
Akinobu Mita | 087975b | 2009-06-27 15:35:15 +0900 | [diff] [blame] | 332 | if (!low_pfn(pmd_pfn(*pmd)) || !pmd_present(*pmd) || pmd_large(*pmd)) |
| 333 | goto out; |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 334 | |
Akinobu Mita | 087975b | 2009-06-27 15:35:15 +0900 | [diff] [blame] | 335 | pte = pte_offset_kernel(pmd, address); |
| 336 | printk("*pte = %0*Lx ", sizeof(*pte) * 2, (u64)pte_val(*pte)); |
| 337 | out: |
Harvey Harrison | 1156e09 | 2008-01-30 13:34:10 +0100 | [diff] [blame] | 338 | printk("\n"); |
Ingo Molnar | f2f13a8 | 2009-02-20 22:50:24 +0100 | [diff] [blame] | 339 | } |
| 340 | |
| 341 | #else /* CONFIG_X86_64: */ |
| 342 | |
| 343 | void vmalloc_sync_all(void) |
| 344 | { |
Haicheng Li | 6afb515 | 2010-05-19 17:42:14 +0800 | [diff] [blame] | 345 | sync_global_pgds(VMALLOC_START & PGDIR_MASK, VMALLOC_END); |
Ingo Molnar | f2f13a8 | 2009-02-20 22:50:24 +0100 | [diff] [blame] | 346 | } |
| 347 | |
| 348 | /* |
| 349 | * 64-bit: |
| 350 | * |
| 351 | * Handle a fault on the vmalloc area |
| 352 | * |
| 353 | * This assumes no large pages in there. |
| 354 | */ |
Masami Hiramatsu | 62c9295 | 2009-08-27 13:23:11 -0400 | [diff] [blame] | 355 | static noinline __kprobes int vmalloc_fault(unsigned long address) |
Ingo Molnar | f2f13a8 | 2009-02-20 22:50:24 +0100 | [diff] [blame] | 356 | { |
| 357 | pgd_t *pgd, *pgd_ref; |
| 358 | pud_t *pud, *pud_ref; |
| 359 | pmd_t *pmd, *pmd_ref; |
| 360 | pte_t *pte, *pte_ref; |
| 361 | |
| 362 | /* Make sure we are in vmalloc area: */ |
| 363 | if (!(address >= VMALLOC_START && address < VMALLOC_END)) |
| 364 | return -1; |
| 365 | |
Frederic Weisbecker | ebc8827 | 2010-09-27 18:50:51 +0200 | [diff] [blame] | 366 | WARN_ON_ONCE(in_nmi()); |
| 367 | |
Ingo Molnar | f2f13a8 | 2009-02-20 22:50:24 +0100 | [diff] [blame] | 368 | /* |
| 369 | * Copy kernel mappings over when needed. This can also |
| 370 | * happen within a race in page table update. In the later |
| 371 | * case just flush: |
| 372 | */ |
| 373 | pgd = pgd_offset(current->active_mm, address); |
| 374 | pgd_ref = pgd_offset_k(address); |
| 375 | if (pgd_none(*pgd_ref)) |
| 376 | return -1; |
| 377 | |
| 378 | if (pgd_none(*pgd)) |
| 379 | set_pgd(pgd, *pgd_ref); |
| 380 | else |
| 381 | BUG_ON(pgd_page_vaddr(*pgd) != pgd_page_vaddr(*pgd_ref)); |
| 382 | |
| 383 | /* |
| 384 | * Below here mismatches are bugs because these lower tables |
| 385 | * are shared: |
| 386 | */ |
| 387 | |
| 388 | pud = pud_offset(pgd, address); |
| 389 | pud_ref = pud_offset(pgd_ref, address); |
| 390 | if (pud_none(*pud_ref)) |
| 391 | return -1; |
| 392 | |
| 393 | if (pud_none(*pud) || pud_page_vaddr(*pud) != pud_page_vaddr(*pud_ref)) |
| 394 | BUG(); |
| 395 | |
| 396 | pmd = pmd_offset(pud, address); |
| 397 | pmd_ref = pmd_offset(pud_ref, address); |
| 398 | if (pmd_none(*pmd_ref)) |
| 399 | return -1; |
| 400 | |
| 401 | if (pmd_none(*pmd) || pmd_page(*pmd) != pmd_page(*pmd_ref)) |
| 402 | BUG(); |
| 403 | |
| 404 | pte_ref = pte_offset_kernel(pmd_ref, address); |
| 405 | if (!pte_present(*pte_ref)) |
| 406 | return -1; |
| 407 | |
| 408 | pte = pte_offset_kernel(pmd, address); |
| 409 | |
| 410 | /* |
| 411 | * Don't use pte_page here, because the mappings can point |
| 412 | * outside mem_map, and the NUMA hash lookup cannot handle |
| 413 | * that: |
| 414 | */ |
| 415 | if (!pte_present(*pte) || pte_pfn(*pte) != pte_pfn(*pte_ref)) |
| 416 | BUG(); |
| 417 | |
| 418 | return 0; |
| 419 | } |
| 420 | |
| 421 | static const char errata93_warning[] = |
Joe Perches | ad361c9 | 2009-07-06 13:05:40 -0700 | [diff] [blame] | 422 | KERN_ERR |
| 423 | "******* Your BIOS seems to not contain a fix for K8 errata #93\n" |
| 424 | "******* Working around it, but it may cause SEGVs or burn power.\n" |
| 425 | "******* Please consider a BIOS update.\n" |
| 426 | "******* Disabling USB legacy in the BIOS may also help.\n"; |
Ingo Molnar | f2f13a8 | 2009-02-20 22:50:24 +0100 | [diff] [blame] | 427 | |
| 428 | /* |
| 429 | * No vm86 mode in 64-bit mode: |
| 430 | */ |
| 431 | static inline void |
| 432 | check_v8086_mode(struct pt_regs *regs, unsigned long address, |
| 433 | struct task_struct *tsk) |
| 434 | { |
| 435 | } |
| 436 | |
| 437 | static int bad_address(void *p) |
| 438 | { |
| 439 | unsigned long dummy; |
| 440 | |
| 441 | return probe_kernel_address((unsigned long *)p, dummy); |
| 442 | } |
| 443 | |
| 444 | static void dump_pagetable(unsigned long address) |
| 445 | { |
Akinobu Mita | 087975b | 2009-06-27 15:35:15 +0900 | [diff] [blame] | 446 | pgd_t *base = __va(read_cr3() & PHYSICAL_PAGE_MASK); |
| 447 | pgd_t *pgd = base + pgd_index(address); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 448 | pud_t *pud; |
| 449 | pmd_t *pmd; |
| 450 | pte_t *pte; |
| 451 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 452 | if (bad_address(pgd)) |
| 453 | goto bad; |
| 454 | |
Jan Beulich | d646bce | 2006-02-03 21:51:47 +0100 | [diff] [blame] | 455 | printk("PGD %lx ", pgd_val(*pgd)); |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 456 | |
| 457 | if (!pgd_present(*pgd)) |
| 458 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 459 | |
Andi Kleen | d2ae5b5 | 2006-06-26 13:57:56 +0200 | [diff] [blame] | 460 | pud = pud_offset(pgd, address); |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 461 | if (bad_address(pud)) |
| 462 | goto bad; |
| 463 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 464 | printk("PUD %lx ", pud_val(*pud)); |
Andi Kleen | b536022 | 2008-02-04 16:48:09 +0100 | [diff] [blame] | 465 | if (!pud_present(*pud) || pud_large(*pud)) |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 466 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 467 | |
| 468 | pmd = pmd_offset(pud, address); |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 469 | if (bad_address(pmd)) |
| 470 | goto bad; |
| 471 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 472 | printk("PMD %lx ", pmd_val(*pmd)); |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 473 | if (!pmd_present(*pmd) || pmd_large(*pmd)) |
| 474 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 475 | |
| 476 | pte = pte_offset_kernel(pmd, address); |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 477 | if (bad_address(pte)) |
| 478 | goto bad; |
| 479 | |
Harvey Harrison | 33cb524 | 2008-01-30 13:32:19 +0100 | [diff] [blame] | 480 | printk("PTE %lx", pte_val(*pte)); |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 481 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 482 | printk("\n"); |
| 483 | return; |
| 484 | bad: |
| 485 | printk("BAD\n"); |
| 486 | } |
| 487 | |
Ingo Molnar | f2f13a8 | 2009-02-20 22:50:24 +0100 | [diff] [blame] | 488 | #endif /* CONFIG_X86_64 */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 489 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 490 | /* |
| 491 | * Workaround for K8 erratum #93 & buggy BIOS. |
| 492 | * |
| 493 | * BIOS SMM functions are required to use a specific workaround |
| 494 | * to avoid corruption of the 64bit RIP register on C stepping K8. |
| 495 | * |
| 496 | * A lot of BIOS that didn't get tested properly miss this. |
| 497 | * |
| 498 | * The OS sees this as a page fault with the upper 32bits of RIP cleared. |
| 499 | * Try to work around it here. |
| 500 | * |
| 501 | * Note we only handle faults in kernel here. |
| 502 | * Does nothing on 32-bit. |
Harvey Harrison | fdfe8aa | 2008-01-30 13:33:13 +0100 | [diff] [blame] | 503 | */ |
Harvey Harrison | 33cb524 | 2008-01-30 13:32:19 +0100 | [diff] [blame] | 504 | static int is_errata93(struct pt_regs *regs, unsigned long address) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 505 | { |
Harvey Harrison | fdfe8aa | 2008-01-30 13:33:13 +0100 | [diff] [blame] | 506 | #ifdef CONFIG_X86_64 |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 507 | if (address != regs->ip) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 508 | return 0; |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 509 | |
Harvey Harrison | 33cb524 | 2008-01-30 13:32:19 +0100 | [diff] [blame] | 510 | if ((address >> 32) != 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 511 | return 0; |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 512 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 513 | address |= 0xffffffffUL << 32; |
Harvey Harrison | 33cb524 | 2008-01-30 13:32:19 +0100 | [diff] [blame] | 514 | if ((address >= (u64)_stext && address <= (u64)_etext) || |
| 515 | (address >= MODULES_VADDR && address <= MODULES_END)) { |
Ingo Molnar | a454ab3 | 2009-05-03 10:09:03 +0200 | [diff] [blame] | 516 | printk_once(errata93_warning); |
H. Peter Anvin | 65ea5b0 | 2008-01-30 13:30:56 +0100 | [diff] [blame] | 517 | regs->ip = address; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 518 | return 1; |
| 519 | } |
Harvey Harrison | fdfe8aa | 2008-01-30 13:33:13 +0100 | [diff] [blame] | 520 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 521 | return 0; |
Harvey Harrison | 33cb524 | 2008-01-30 13:32:19 +0100 | [diff] [blame] | 522 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 523 | |
Harvey Harrison | 35f3266 | 2008-01-30 13:34:09 +0100 | [diff] [blame] | 524 | /* |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 525 | * Work around K8 erratum #100 K8 in compat mode occasionally jumps |
| 526 | * to illegal addresses >4GB. |
| 527 | * |
| 528 | * We catch this in the page fault handler because these addresses |
| 529 | * are not reachable. Just detect this case and return. Any code |
Harvey Harrison | 35f3266 | 2008-01-30 13:34:09 +0100 | [diff] [blame] | 530 | * segment in LDT is compatibility mode. |
| 531 | */ |
| 532 | static int is_errata100(struct pt_regs *regs, unsigned long address) |
| 533 | { |
| 534 | #ifdef CONFIG_X86_64 |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 535 | if ((regs->cs == __USER32_CS || (regs->cs & (1<<2))) && (address >> 32)) |
Harvey Harrison | 35f3266 | 2008-01-30 13:34:09 +0100 | [diff] [blame] | 536 | return 1; |
| 537 | #endif |
| 538 | return 0; |
| 539 | } |
| 540 | |
Harvey Harrison | 29caf2f | 2008-01-30 13:34:09 +0100 | [diff] [blame] | 541 | static int is_f00f_bug(struct pt_regs *regs, unsigned long address) |
| 542 | { |
| 543 | #ifdef CONFIG_X86_F00F_BUG |
| 544 | unsigned long nr; |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 545 | |
Harvey Harrison | 29caf2f | 2008-01-30 13:34:09 +0100 | [diff] [blame] | 546 | /* |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 547 | * Pentium F0 0F C7 C8 bug workaround: |
Harvey Harrison | 29caf2f | 2008-01-30 13:34:09 +0100 | [diff] [blame] | 548 | */ |
| 549 | if (boot_cpu_data.f00f_bug) { |
| 550 | nr = (address - idt_descr.address) >> 3; |
| 551 | |
| 552 | if (nr == 6) { |
| 553 | do_invalid_op(regs, 0); |
| 554 | return 1; |
| 555 | } |
| 556 | } |
| 557 | #endif |
| 558 | return 0; |
| 559 | } |
| 560 | |
Ingo Molnar | 8f76614 | 2009-02-20 23:00:29 +0100 | [diff] [blame] | 561 | static const char nx_warning[] = KERN_CRIT |
| 562 | "kernel tried to execute NX-protected page - exploit attempt? (uid: %d)\n"; |
| 563 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 564 | static void |
| 565 | show_fault_oops(struct pt_regs *regs, unsigned long error_code, |
| 566 | unsigned long address) |
Harvey Harrison | b3279c7 | 2008-01-30 13:34:10 +0100 | [diff] [blame] | 567 | { |
Harvey Harrison | 1156e09 | 2008-01-30 13:34:10 +0100 | [diff] [blame] | 568 | if (!oops_may_print()) |
| 569 | return; |
| 570 | |
Harvey Harrison | 1156e09 | 2008-01-30 13:34:10 +0100 | [diff] [blame] | 571 | if (error_code & PF_INSTR) { |
Harvey Harrison | 93809be | 2008-02-01 17:49:43 +0100 | [diff] [blame] | 572 | unsigned int level; |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 573 | |
Harvey Harrison | 1156e09 | 2008-01-30 13:34:10 +0100 | [diff] [blame] | 574 | pte_t *pte = lookup_address(address, &level); |
| 575 | |
Ingo Molnar | 8f76614 | 2009-02-20 23:00:29 +0100 | [diff] [blame] | 576 | if (pte && pte_present(*pte) && !pte_exec(*pte)) |
| 577 | printk(nx_warning, current_uid()); |
Harvey Harrison | 1156e09 | 2008-01-30 13:34:10 +0100 | [diff] [blame] | 578 | } |
Harvey Harrison | fd40d6e | 2008-01-30 13:34:11 +0100 | [diff] [blame] | 579 | |
Harvey Harrison | 1156e09 | 2008-01-30 13:34:10 +0100 | [diff] [blame] | 580 | printk(KERN_ALERT "BUG: unable to handle kernel "); |
| 581 | if (address < PAGE_SIZE) |
| 582 | printk(KERN_CONT "NULL pointer dereference"); |
| 583 | else |
| 584 | printk(KERN_CONT "paging request"); |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 585 | |
Vegard Nossum | f294a8c | 2008-07-01 15:38:13 +0200 | [diff] [blame] | 586 | printk(KERN_CONT " at %p\n", (void *) address); |
Harvey Harrison | 19f0dda | 2008-01-30 13:34:10 +0100 | [diff] [blame] | 587 | printk(KERN_ALERT "IP:"); |
Harvey Harrison | b3279c7 | 2008-01-30 13:34:10 +0100 | [diff] [blame] | 588 | printk_address(regs->ip, 1); |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 589 | |
Harvey Harrison | b3279c7 | 2008-01-30 13:34:10 +0100 | [diff] [blame] | 590 | dump_pagetable(address); |
| 591 | } |
| 592 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 593 | static noinline void |
| 594 | pgtable_bad(struct pt_regs *regs, unsigned long error_code, |
| 595 | unsigned long address) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 596 | { |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 597 | struct task_struct *tsk; |
| 598 | unsigned long flags; |
| 599 | int sig; |
| 600 | |
| 601 | flags = oops_begin(); |
| 602 | tsk = current; |
| 603 | sig = SIGKILL; |
Jan Beulich | 1209140 | 2005-09-12 18:49:24 +0200 | [diff] [blame] | 604 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 605 | printk(KERN_ALERT "%s: Corrupted page table at address %lx\n", |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 606 | tsk->comm, address); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 607 | dump_pagetable(address); |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 608 | |
| 609 | tsk->thread.cr2 = address; |
| 610 | tsk->thread.trap_no = 14; |
| 611 | tsk->thread.error_code = error_code; |
| 612 | |
Jan Beulich | 22f5991 | 2008-01-30 13:31:23 +0100 | [diff] [blame] | 613 | if (__die("Bad pagetable", regs, error_code)) |
Alexander van Heukelum | 874d93d | 2008-10-22 12:00:09 +0200 | [diff] [blame] | 614 | sig = 0; |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 615 | |
Alexander van Heukelum | 874d93d | 2008-10-22 12:00:09 +0200 | [diff] [blame] | 616 | oops_end(flags, regs, sig); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 617 | } |
| 618 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 619 | static noinline void |
| 620 | no_context(struct pt_regs *regs, unsigned long error_code, |
| 621 | unsigned long address) |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 622 | { |
| 623 | struct task_struct *tsk = current; |
Ingo Molnar | 1980307 | 2009-01-21 10:39:51 +0100 | [diff] [blame] | 624 | unsigned long *stackend; |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 625 | unsigned long flags; |
| 626 | int sig; |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 627 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 628 | /* Are we prepared to handle this kernel fault? */ |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 629 | if (fixup_exception(regs)) |
| 630 | return; |
| 631 | |
| 632 | /* |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 633 | * 32-bit: |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 634 | * |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 635 | * Valid to do another page fault here, because if this fault |
| 636 | * had been triggered by is_prefetch fixup_exception would have |
| 637 | * handled it. |
| 638 | * |
| 639 | * 64-bit: |
| 640 | * |
| 641 | * Hall of shame of CPU/BIOS bugs. |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 642 | */ |
| 643 | if (is_prefetch(regs, error_code, address)) |
| 644 | return; |
| 645 | |
| 646 | if (is_errata93(regs, address)) |
| 647 | return; |
| 648 | |
| 649 | /* |
| 650 | * Oops. The kernel tried to access some bad page. We'll have to |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 651 | * terminate things with extreme prejudice: |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 652 | */ |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 653 | flags = oops_begin(); |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 654 | |
| 655 | show_fault_oops(regs, error_code, address); |
| 656 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 657 | stackend = end_of_stack(tsk); |
Jan Beulich | 0e7810b | 2009-11-20 14:00:14 +0000 | [diff] [blame] | 658 | if (tsk != &init_task && *stackend != STACK_END_MAGIC) |
Ingo Molnar | 1980307 | 2009-01-21 10:39:51 +0100 | [diff] [blame] | 659 | printk(KERN_ALERT "Thread overran stack, or stack corrupted\n"); |
| 660 | |
Ingo Molnar | 1cc9954 | 2009-02-20 23:07:48 +0100 | [diff] [blame] | 661 | tsk->thread.cr2 = address; |
| 662 | tsk->thread.trap_no = 14; |
| 663 | tsk->thread.error_code = error_code; |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 664 | |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 665 | sig = SIGKILL; |
| 666 | if (__die("Oops", regs, error_code)) |
| 667 | sig = 0; |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 668 | |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 669 | /* Executive summary in case the body of the oops scrolled away */ |
| 670 | printk(KERN_EMERG "CR2: %016lx\n", address); |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 671 | |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 672 | oops_end(flags, regs, sig); |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 673 | } |
| 674 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 675 | /* |
| 676 | * Print out info about fatal segfaults, if the show_unhandled_signals |
| 677 | * sysctl is set: |
| 678 | */ |
| 679 | static inline void |
| 680 | show_signal_msg(struct pt_regs *regs, unsigned long error_code, |
| 681 | unsigned long address, struct task_struct *tsk) |
| 682 | { |
| 683 | if (!unhandled_signal(tsk, SIGSEGV)) |
| 684 | return; |
| 685 | |
| 686 | if (!printk_ratelimit()) |
| 687 | return; |
| 688 | |
Roland Dreier | a1a08d1 | 2009-07-11 00:10:04 -0700 | [diff] [blame] | 689 | printk("%s%s[%d]: segfault at %lx ip %p sp %p error %lx", |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 690 | task_pid_nr(tsk) > 1 ? KERN_INFO : KERN_EMERG, |
| 691 | tsk->comm, task_pid_nr(tsk), address, |
| 692 | (void *)regs->ip, (void *)regs->sp, error_code); |
| 693 | |
| 694 | print_vma_addr(KERN_CONT " in ", regs->ip); |
| 695 | |
| 696 | printk(KERN_CONT "\n"); |
| 697 | } |
| 698 | |
| 699 | static void |
| 700 | __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code, |
| 701 | unsigned long address, int si_code) |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 702 | { |
| 703 | struct task_struct *tsk = current; |
| 704 | |
| 705 | /* User mode accesses just cause a SIGSEGV */ |
| 706 | if (error_code & PF_USER) { |
| 707 | /* |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 708 | * It's possible to have interrupts off here: |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 709 | */ |
| 710 | local_irq_enable(); |
| 711 | |
| 712 | /* |
| 713 | * Valid to do another page fault here because this one came |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 714 | * from user space: |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 715 | */ |
| 716 | if (is_prefetch(regs, error_code, address)) |
| 717 | return; |
| 718 | |
| 719 | if (is_errata100(regs, address)) |
| 720 | return; |
| 721 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 722 | if (unlikely(show_unhandled_signals)) |
| 723 | show_signal_msg(regs, error_code, address, tsk); |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 724 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 725 | /* Kernel addresses are always protection faults: */ |
| 726 | tsk->thread.cr2 = address; |
| 727 | tsk->thread.error_code = error_code | (address >= TASK_SIZE); |
| 728 | tsk->thread.trap_no = 14; |
| 729 | |
Andi Kleen | f672b49 | 2010-09-27 22:05:55 +0200 | [diff] [blame] | 730 | force_sig_info_fault(SIGSEGV, si_code, address, tsk, 0); |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 731 | |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 732 | return; |
| 733 | } |
| 734 | |
| 735 | if (is_f00f_bug(regs, address)) |
| 736 | return; |
| 737 | |
| 738 | no_context(regs, error_code, address); |
| 739 | } |
| 740 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 741 | static noinline void |
| 742 | bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code, |
| 743 | unsigned long address) |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 744 | { |
| 745 | __bad_area_nosemaphore(regs, error_code, address, SEGV_MAPERR); |
| 746 | } |
| 747 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 748 | static void |
| 749 | __bad_area(struct pt_regs *regs, unsigned long error_code, |
| 750 | unsigned long address, int si_code) |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 751 | { |
| 752 | struct mm_struct *mm = current->mm; |
| 753 | |
| 754 | /* |
| 755 | * Something tried to access memory that isn't in our memory map.. |
| 756 | * Fix it, but check if it's kernel or user first.. |
| 757 | */ |
| 758 | up_read(&mm->mmap_sem); |
| 759 | |
| 760 | __bad_area_nosemaphore(regs, error_code, address, si_code); |
| 761 | } |
| 762 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 763 | static noinline void |
| 764 | bad_area(struct pt_regs *regs, unsigned long error_code, unsigned long address) |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 765 | { |
| 766 | __bad_area(regs, error_code, address, SEGV_MAPERR); |
| 767 | } |
| 768 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 769 | static noinline void |
| 770 | bad_area_access_error(struct pt_regs *regs, unsigned long error_code, |
| 771 | unsigned long address) |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 772 | { |
| 773 | __bad_area(regs, error_code, address, SEGV_ACCERR); |
| 774 | } |
| 775 | |
| 776 | /* TODO: fixup for "mm-invoke-oom-killer-from-page-fault.patch" */ |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 777 | static void |
| 778 | out_of_memory(struct pt_regs *regs, unsigned long error_code, |
| 779 | unsigned long address) |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 780 | { |
| 781 | /* |
| 782 | * We ran out of memory, call the OOM killer, and return the userspace |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 783 | * (which will retry the fault, or kill us if we got oom-killed): |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 784 | */ |
| 785 | up_read(¤t->mm->mmap_sem); |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 786 | |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 787 | pagefault_out_of_memory(); |
| 788 | } |
| 789 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 790 | static void |
Andi Kleen | a6e04aa | 2009-09-16 11:50:09 +0200 | [diff] [blame] | 791 | do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address, |
| 792 | unsigned int fault) |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 793 | { |
| 794 | struct task_struct *tsk = current; |
| 795 | struct mm_struct *mm = tsk->mm; |
Andi Kleen | a6e04aa | 2009-09-16 11:50:09 +0200 | [diff] [blame] | 796 | int code = BUS_ADRERR; |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 797 | |
| 798 | up_read(&mm->mmap_sem); |
| 799 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 800 | /* Kernel mode? Handle exceptions or die: */ |
Linus Torvalds | 9605456 | 2010-08-13 09:49:20 -0700 | [diff] [blame] | 801 | if (!(error_code & PF_USER)) { |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 802 | no_context(regs, error_code, address); |
Linus Torvalds | 9605456 | 2010-08-13 09:49:20 -0700 | [diff] [blame] | 803 | return; |
| 804 | } |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 805 | |
Ingo Molnar | cd1b68f | 2009-02-20 23:39:02 +0100 | [diff] [blame] | 806 | /* User-space => ok to do another page fault: */ |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 807 | if (is_prefetch(regs, error_code, address)) |
| 808 | return; |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 809 | |
| 810 | tsk->thread.cr2 = address; |
| 811 | tsk->thread.error_code = error_code; |
| 812 | tsk->thread.trap_no = 14; |
| 813 | |
Andi Kleen | a6e04aa | 2009-09-16 11:50:09 +0200 | [diff] [blame] | 814 | #ifdef CONFIG_MEMORY_FAILURE |
Andi Kleen | f672b49 | 2010-09-27 22:05:55 +0200 | [diff] [blame] | 815 | if (fault & (VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE)) { |
Andi Kleen | a6e04aa | 2009-09-16 11:50:09 +0200 | [diff] [blame] | 816 | printk(KERN_ERR |
| 817 | "MCE: Killing %s:%d due to hardware memory corruption fault at %lx\n", |
| 818 | tsk->comm, tsk->pid, address); |
| 819 | code = BUS_MCEERR_AR; |
| 820 | } |
| 821 | #endif |
Andi Kleen | f672b49 | 2010-09-27 22:05:55 +0200 | [diff] [blame] | 822 | force_sig_info_fault(SIGBUS, code, address, tsk, fault); |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 823 | } |
| 824 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 825 | static noinline void |
| 826 | mm_fault_error(struct pt_regs *regs, unsigned long error_code, |
| 827 | unsigned long address, unsigned int fault) |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 828 | { |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 829 | if (fault & VM_FAULT_OOM) { |
Andrey Vagin | f862685 | 2011-03-09 15:22:23 -0800 | [diff] [blame] | 830 | /* Kernel mode? Handle exceptions or die: */ |
| 831 | if (!(error_code & PF_USER)) { |
| 832 | up_read(¤t->mm->mmap_sem); |
| 833 | no_context(regs, error_code, address); |
| 834 | return; |
| 835 | } |
| 836 | |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 837 | out_of_memory(regs, error_code, address); |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 838 | } else { |
Andi Kleen | f672b49 | 2010-09-27 22:05:55 +0200 | [diff] [blame] | 839 | if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON| |
| 840 | VM_FAULT_HWPOISON_LARGE)) |
Andi Kleen | a6e04aa | 2009-09-16 11:50:09 +0200 | [diff] [blame] | 841 | do_sigbus(regs, error_code, address, fault); |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 842 | else |
| 843 | BUG(); |
| 844 | } |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 845 | } |
| 846 | |
Thomas Gleixner | d8b57bb | 2008-02-06 22:39:43 +0100 | [diff] [blame] | 847 | static int spurious_fault_check(unsigned long error_code, pte_t *pte) |
| 848 | { |
| 849 | if ((error_code & PF_WRITE) && !pte_write(*pte)) |
| 850 | return 0; |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 851 | |
Thomas Gleixner | d8b57bb | 2008-02-06 22:39:43 +0100 | [diff] [blame] | 852 | if ((error_code & PF_INSTR) && !pte_exec(*pte)) |
| 853 | return 0; |
| 854 | |
| 855 | return 1; |
| 856 | } |
| 857 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 858 | /* |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 859 | * Handle a spurious fault caused by a stale TLB entry. |
| 860 | * |
| 861 | * This allows us to lazily refresh the TLB when increasing the |
| 862 | * permissions of a kernel page (RO -> RW or NX -> X). Doing it |
| 863 | * eagerly is very expensive since that implies doing a full |
| 864 | * cross-processor TLB flush, even if no stale TLB entries exist |
| 865 | * on other processors. |
| 866 | * |
Jeremy Fitzhardinge | 5b727a3 | 2008-01-30 13:34:11 +0100 | [diff] [blame] | 867 | * There are no security implications to leaving a stale TLB when |
| 868 | * increasing the permissions on a page. |
| 869 | */ |
Masami Hiramatsu | 62c9295 | 2009-08-27 13:23:11 -0400 | [diff] [blame] | 870 | static noinline __kprobes int |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 871 | spurious_fault(unsigned long error_code, unsigned long address) |
Jeremy Fitzhardinge | 5b727a3 | 2008-01-30 13:34:11 +0100 | [diff] [blame] | 872 | { |
| 873 | pgd_t *pgd; |
| 874 | pud_t *pud; |
| 875 | pmd_t *pmd; |
| 876 | pte_t *pte; |
Steven Rostedt | 3c3e569 | 2009-02-19 11:46:36 -0500 | [diff] [blame] | 877 | int ret; |
Jeremy Fitzhardinge | 5b727a3 | 2008-01-30 13:34:11 +0100 | [diff] [blame] | 878 | |
| 879 | /* Reserved-bit violation or user access to kernel space? */ |
| 880 | if (error_code & (PF_USER | PF_RSVD)) |
| 881 | return 0; |
| 882 | |
| 883 | pgd = init_mm.pgd + pgd_index(address); |
| 884 | if (!pgd_present(*pgd)) |
| 885 | return 0; |
| 886 | |
| 887 | pud = pud_offset(pgd, address); |
| 888 | if (!pud_present(*pud)) |
| 889 | return 0; |
| 890 | |
Thomas Gleixner | d8b57bb | 2008-02-06 22:39:43 +0100 | [diff] [blame] | 891 | if (pud_large(*pud)) |
| 892 | return spurious_fault_check(error_code, (pte_t *) pud); |
| 893 | |
Jeremy Fitzhardinge | 5b727a3 | 2008-01-30 13:34:11 +0100 | [diff] [blame] | 894 | pmd = pmd_offset(pud, address); |
| 895 | if (!pmd_present(*pmd)) |
| 896 | return 0; |
| 897 | |
Thomas Gleixner | d8b57bb | 2008-02-06 22:39:43 +0100 | [diff] [blame] | 898 | if (pmd_large(*pmd)) |
| 899 | return spurious_fault_check(error_code, (pte_t *) pmd); |
| 900 | |
Shaohua Li | 660a293 | 2010-07-27 16:06:28 +0800 | [diff] [blame] | 901 | /* |
| 902 | * Note: don't use pte_present() here, since it returns true |
| 903 | * if the _PAGE_PROTNONE bit is set. However, this aliases the |
| 904 | * _PAGE_GLOBAL bit, which for kernel pages give false positives |
| 905 | * when CONFIG_DEBUG_PAGEALLOC is used. |
| 906 | */ |
Jeremy Fitzhardinge | 5b727a3 | 2008-01-30 13:34:11 +0100 | [diff] [blame] | 907 | pte = pte_offset_kernel(pmd, address); |
Shaohua Li | 660a293 | 2010-07-27 16:06:28 +0800 | [diff] [blame] | 908 | if (!(pte_flags(*pte) & _PAGE_PRESENT)) |
Jeremy Fitzhardinge | 5b727a3 | 2008-01-30 13:34:11 +0100 | [diff] [blame] | 909 | return 0; |
| 910 | |
Steven Rostedt | 3c3e569 | 2009-02-19 11:46:36 -0500 | [diff] [blame] | 911 | ret = spurious_fault_check(error_code, pte); |
| 912 | if (!ret) |
| 913 | return 0; |
| 914 | |
| 915 | /* |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 916 | * Make sure we have permissions in PMD. |
| 917 | * If not, then there's a bug in the page tables: |
Steven Rostedt | 3c3e569 | 2009-02-19 11:46:36 -0500 | [diff] [blame] | 918 | */ |
| 919 | ret = spurious_fault_check(error_code, (pte_t *) pmd); |
| 920 | WARN_ONCE(!ret, "PMD has incorrect permission bits\n"); |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 921 | |
Steven Rostedt | 3c3e569 | 2009-02-19 11:46:36 -0500 | [diff] [blame] | 922 | return ret; |
Jeremy Fitzhardinge | 5b727a3 | 2008-01-30 13:34:11 +0100 | [diff] [blame] | 923 | } |
| 924 | |
Masoud Asgharifard Sharbiani | abd4f75 | 2007-07-22 11:12:28 +0200 | [diff] [blame] | 925 | int show_unhandled_signals = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 926 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 927 | static inline int |
Michel Lespinasse | 68da336 | 2010-10-26 14:21:58 -0700 | [diff] [blame] | 928 | access_error(unsigned long error_code, struct vm_area_struct *vma) |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 929 | { |
Michel Lespinasse | 68da336 | 2010-10-26 14:21:58 -0700 | [diff] [blame] | 930 | if (error_code & PF_WRITE) { |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 931 | /* write, present and write, not present: */ |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 932 | if (unlikely(!(vma->vm_flags & VM_WRITE))) |
| 933 | return 1; |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 934 | return 0; |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 935 | } |
| 936 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 937 | /* read, present: */ |
| 938 | if (unlikely(error_code & PF_PROT)) |
| 939 | return 1; |
| 940 | |
| 941 | /* read, not present: */ |
| 942 | if (unlikely(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))) |
| 943 | return 1; |
| 944 | |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 945 | return 0; |
| 946 | } |
| 947 | |
Hiroshi Shimamoto | 0973a06 | 2009-02-04 15:24:09 -0800 | [diff] [blame] | 948 | static int fault_in_kernel_space(unsigned long address) |
| 949 | { |
Ingo Molnar | d951734 | 2009-02-20 23:32:28 +0100 | [diff] [blame] | 950 | return address >= TASK_SIZE_MAX; |
Hiroshi Shimamoto | 0973a06 | 2009-02-04 15:24:09 -0800 | [diff] [blame] | 951 | } |
| 952 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 953 | /* |
| 954 | * This routine handles page faults. It determines the address, |
| 955 | * and the problem, and then passes it off to one of the appropriate |
| 956 | * routines. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 957 | */ |
Ingo Molnar | c3731c6 | 2009-02-20 23:22:34 +0100 | [diff] [blame] | 958 | dotraplinkage void __kprobes |
| 959 | do_page_fault(struct pt_regs *regs, unsigned long error_code) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 960 | { |
Harvey Harrison | 33cb524 | 2008-01-30 13:32:19 +0100 | [diff] [blame] | 961 | struct vm_area_struct *vma; |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 962 | struct task_struct *tsk; |
| 963 | unsigned long address; |
| 964 | struct mm_struct *mm; |
Harvey Harrison | f8c2ee2 | 2008-01-30 13:34:10 +0100 | [diff] [blame] | 965 | int fault; |
Michel Lespinasse | d065bd8 | 2010-10-26 14:21:57 -0700 | [diff] [blame] | 966 | int write = error_code & PF_WRITE; |
| 967 | unsigned int flags = FAULT_FLAG_ALLOW_RETRY | |
| 968 | (write ? FAULT_FLAG_WRITE : 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 969 | |
Arjan van de Ven | a9ba9a3 | 2006-03-25 16:30:10 +0100 | [diff] [blame] | 970 | tsk = current; |
| 971 | mm = tsk->mm; |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 972 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 973 | /* Get the faulting address: */ |
Glauber de Oliveira Costa | f51c945 | 2007-07-22 11:12:29 +0200 | [diff] [blame] | 974 | address = read_cr2(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 975 | |
Vegard Nossum | f856129 | 2008-04-04 00:53:23 +0200 | [diff] [blame] | 976 | /* |
| 977 | * Detect and handle instructions that would cause a page fault for |
| 978 | * both a tracked kernel page and a userspace page. |
| 979 | */ |
| 980 | if (kmemcheck_active(regs)) |
| 981 | kmemcheck_hide(regs); |
Ingo Molnar | 5dfaf90 | 2009-06-16 10:23:32 +0200 | [diff] [blame] | 982 | prefetchw(&mm->mmap_sem); |
Vegard Nossum | f856129 | 2008-04-04 00:53:23 +0200 | [diff] [blame] | 983 | |
Pekka Paalanen | 0fd0e3d | 2008-05-12 21:20:57 +0200 | [diff] [blame] | 984 | if (unlikely(kmmio_fault(regs, address))) |
Pekka Paalanen | 8606978 | 2008-05-12 21:20:56 +0200 | [diff] [blame] | 985 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 986 | |
| 987 | /* |
| 988 | * We fault-in kernel-space virtual memory on-demand. The |
| 989 | * 'reference' page table is init_mm.pgd. |
| 990 | * |
| 991 | * NOTE! We MUST NOT take any locks for this case. We may |
| 992 | * be in an interrupt or a critical region, and should |
| 993 | * only copy the information from the master page table, |
| 994 | * nothing more. |
| 995 | * |
| 996 | * This verifies that the fault happens in kernel space |
| 997 | * (error_code & 4) == 0, and that the fault was not a |
Jan Beulich | 8b1bde9 | 2006-01-11 22:42:23 +0100 | [diff] [blame] | 998 | * protection error (error_code & 9) == 0. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 999 | */ |
Hiroshi Shimamoto | 0973a06 | 2009-02-04 15:24:09 -0800 | [diff] [blame] | 1000 | if (unlikely(fault_in_kernel_space(address))) { |
Vegard Nossum | f856129 | 2008-04-04 00:53:23 +0200 | [diff] [blame] | 1001 | if (!(error_code & (PF_RSVD | PF_USER | PF_PROT))) { |
| 1002 | if (vmalloc_fault(address) >= 0) |
| 1003 | return; |
| 1004 | |
| 1005 | if (kmemcheck_fault(regs, address, error_code)) |
| 1006 | return; |
| 1007 | } |
Jeremy Fitzhardinge | 5b727a3 | 2008-01-30 13:34:11 +0100 | [diff] [blame] | 1008 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 1009 | /* Can handle a stale RO->RW TLB: */ |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 1010 | if (spurious_fault(error_code, address)) |
Jeremy Fitzhardinge | 5b727a3 | 2008-01-30 13:34:11 +0100 | [diff] [blame] | 1011 | return; |
| 1012 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 1013 | /* kprobes don't want to hook the spurious faults: */ |
Masami Hiramatsu | 9be260a | 2009-02-05 17:12:39 -0500 | [diff] [blame] | 1014 | if (notify_page_fault(regs)) |
| 1015 | return; |
Harvey Harrison | f8c2ee2 | 2008-01-30 13:34:10 +0100 | [diff] [blame] | 1016 | /* |
| 1017 | * Don't take the mm semaphore here. If we fixup a prefetch |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 1018 | * fault we could otherwise deadlock: |
Harvey Harrison | f8c2ee2 | 2008-01-30 13:34:10 +0100 | [diff] [blame] | 1019 | */ |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 1020 | bad_area_nosemaphore(regs, error_code, address); |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 1021 | |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 1022 | return; |
Harvey Harrison | f8c2ee2 | 2008-01-30 13:34:10 +0100 | [diff] [blame] | 1023 | } |
| 1024 | |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 1025 | /* kprobes don't want to hook the spurious faults: */ |
Ingo Molnar | f8a6b2b | 2009-02-13 09:44:22 +0100 | [diff] [blame] | 1026 | if (unlikely(notify_page_fault(regs))) |
Masami Hiramatsu | 9be260a | 2009-02-05 17:12:39 -0500 | [diff] [blame] | 1027 | return; |
Harvey Harrison | f8c2ee2 | 2008-01-30 13:34:10 +0100 | [diff] [blame] | 1028 | /* |
Linus Torvalds | 891cffb | 2008-10-12 13:16:12 -0700 | [diff] [blame] | 1029 | * It's safe to allow irq's after cr2 has been saved and the |
| 1030 | * vmalloc fault has been handled. |
| 1031 | * |
| 1032 | * User-mode registers count as a user access even for any |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 1033 | * potential system fault or CPU buglet: |
Harvey Harrison | f8c2ee2 | 2008-01-30 13:34:10 +0100 | [diff] [blame] | 1034 | */ |
Linus Torvalds | 891cffb | 2008-10-12 13:16:12 -0700 | [diff] [blame] | 1035 | if (user_mode_vm(regs)) { |
| 1036 | local_irq_enable(); |
| 1037 | error_code |= PF_USER; |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 1038 | } else { |
| 1039 | if (regs->flags & X86_EFLAGS_IF) |
| 1040 | local_irq_enable(); |
| 1041 | } |
Jan Beulich | 8c914cb | 2006-03-25 16:29:40 +0100 | [diff] [blame] | 1042 | |
Andi Kleen | 66c5815 | 2006-01-11 22:44:09 +0100 | [diff] [blame] | 1043 | if (unlikely(error_code & PF_RSVD)) |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 1044 | pgtable_bad(regs, error_code, address); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1045 | |
Ingo Molnar | cdd6c48 | 2009-09-21 12:02:48 +0200 | [diff] [blame] | 1046 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, 0, regs, address); |
Peter Zijlstra | 7dd1fcc | 2009-03-13 12:21:33 +0100 | [diff] [blame] | 1047 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1048 | /* |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 1049 | * If we're in an interrupt, have no user context or are running |
| 1050 | * in an atomic region then we must not take the fault: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1051 | */ |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 1052 | if (unlikely(in_atomic() || !mm)) { |
| 1053 | bad_area_nosemaphore(regs, error_code, address); |
| 1054 | return; |
| 1055 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1056 | |
Ingo Molnar | 3a1dfe6 | 2008-10-13 17:49:02 +0200 | [diff] [blame] | 1057 | /* |
| 1058 | * When running in the kernel we expect faults to occur only to |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 1059 | * addresses in user space. All other faults represent errors in |
| 1060 | * the kernel and should generate an OOPS. Unfortunately, in the |
| 1061 | * case of an erroneous fault occurring in a code path which already |
| 1062 | * holds mmap_sem we will deadlock attempting to validate the fault |
| 1063 | * against the address space. Luckily the kernel only validly |
| 1064 | * references user space from well defined areas of code, which are |
| 1065 | * listed in the exceptions table. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1066 | * |
| 1067 | * As the vast majority of faults will be valid we will only perform |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 1068 | * the source reference check when there is a possibility of a |
| 1069 | * deadlock. Attempt to lock the address space, if we cannot we then |
| 1070 | * validate the source. If this is invalid we can skip the address |
| 1071 | * space check, thus avoiding the deadlock: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1072 | */ |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 1073 | if (unlikely(!down_read_trylock(&mm->mmap_sem))) { |
Andi Kleen | 66c5815 | 2006-01-11 22:44:09 +0100 | [diff] [blame] | 1074 | if ((error_code & PF_USER) == 0 && |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 1075 | !search_exception_tables(regs->ip)) { |
| 1076 | bad_area_nosemaphore(regs, error_code, address); |
| 1077 | return; |
| 1078 | } |
Michel Lespinasse | d065bd8 | 2010-10-26 14:21:57 -0700 | [diff] [blame] | 1079 | retry: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1080 | down_read(&mm->mmap_sem); |
Peter Zijlstra | 0100607 | 2009-01-29 16:02:12 +0100 | [diff] [blame] | 1081 | } else { |
| 1082 | /* |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 1083 | * The above down_read_trylock() might have succeeded in |
| 1084 | * which case we'll have missed the might_sleep() from |
| 1085 | * down_read(): |
Peter Zijlstra | 0100607 | 2009-01-29 16:02:12 +0100 | [diff] [blame] | 1086 | */ |
| 1087 | might_sleep(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1088 | } |
| 1089 | |
| 1090 | vma = find_vma(mm, address); |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 1091 | if (unlikely(!vma)) { |
| 1092 | bad_area(regs, error_code, address); |
| 1093 | return; |
| 1094 | } |
| 1095 | if (likely(vma->vm_start <= address)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1096 | goto good_area; |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 1097 | if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) { |
| 1098 | bad_area(regs, error_code, address); |
| 1099 | return; |
| 1100 | } |
Harvey Harrison | 33cb524 | 2008-01-30 13:32:19 +0100 | [diff] [blame] | 1101 | if (error_code & PF_USER) { |
Harvey Harrison | 6f4d368 | 2008-01-30 13:33:13 +0100 | [diff] [blame] | 1102 | /* |
| 1103 | * Accessing the stack below %sp is always a bug. |
| 1104 | * The large cushion allows instructions like enter |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 1105 | * and pusha to work. ("enter $65535, $31" pushes |
Harvey Harrison | 6f4d368 | 2008-01-30 13:33:13 +0100 | [diff] [blame] | 1106 | * 32 pointers and then decrements %sp by 65535.) |
Chuck Ebbert | 03fdc2c | 2006-06-26 13:59:50 +0200 | [diff] [blame] | 1107 | */ |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 1108 | if (unlikely(address + 65536 + 32 * sizeof(unsigned long) < regs->sp)) { |
| 1109 | bad_area(regs, error_code, address); |
| 1110 | return; |
| 1111 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1112 | } |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 1113 | if (unlikely(expand_stack(vma, address))) { |
| 1114 | bad_area(regs, error_code, address); |
| 1115 | return; |
| 1116 | } |
| 1117 | |
| 1118 | /* |
| 1119 | * Ok, we have a good vm_area for this memory access, so |
| 1120 | * we can handle it.. |
| 1121 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1122 | good_area: |
Michel Lespinasse | 68da336 | 2010-10-26 14:21:58 -0700 | [diff] [blame] | 1123 | if (unlikely(access_error(error_code, vma))) { |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 1124 | bad_area_access_error(regs, error_code, address); |
| 1125 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1126 | } |
| 1127 | |
| 1128 | /* |
| 1129 | * If for any reason at all we couldn't handle the fault, |
| 1130 | * make sure we exit gracefully rather than endlessly redo |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 1131 | * the fault: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1132 | */ |
Michel Lespinasse | d065bd8 | 2010-10-26 14:21:57 -0700 | [diff] [blame] | 1133 | fault = handle_mm_fault(mm, vma, address, flags); |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 1134 | |
Nick Piggin | 83c5407 | 2007-07-19 01:47:05 -0700 | [diff] [blame] | 1135 | if (unlikely(fault & VM_FAULT_ERROR)) { |
Nick Piggin | 92181f1 | 2009-01-20 04:24:26 +0100 | [diff] [blame] | 1136 | mm_fault_error(regs, error_code, address, fault); |
| 1137 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1138 | } |
Ingo Molnar | 2d4a716 | 2009-02-20 19:56:40 +0100 | [diff] [blame] | 1139 | |
Michel Lespinasse | d065bd8 | 2010-10-26 14:21:57 -0700 | [diff] [blame] | 1140 | /* |
| 1141 | * Major/minor page fault accounting is only done on the |
| 1142 | * initial attempt. If we go through a retry, it is extremely |
| 1143 | * likely that the page will be found in page cache at that point. |
| 1144 | */ |
| 1145 | if (flags & FAULT_FLAG_ALLOW_RETRY) { |
| 1146 | if (fault & VM_FAULT_MAJOR) { |
| 1147 | tsk->maj_flt++; |
| 1148 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1, 0, |
| 1149 | regs, address); |
| 1150 | } else { |
| 1151 | tsk->min_flt++; |
| 1152 | perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1, 0, |
| 1153 | regs, address); |
| 1154 | } |
| 1155 | if (fault & VM_FAULT_RETRY) { |
| 1156 | /* Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk |
| 1157 | * of starvation. */ |
| 1158 | flags &= ~FAULT_FLAG_ALLOW_RETRY; |
| 1159 | goto retry; |
| 1160 | } |
Peter Zijlstra | ac17dc8 | 2009-03-13 12:21:34 +0100 | [diff] [blame] | 1161 | } |
Harvey Harrison | d729ab3 | 2008-01-30 13:33:23 +0100 | [diff] [blame] | 1162 | |
Ingo Molnar | 8c938f9 | 2009-02-20 22:12:18 +0100 | [diff] [blame] | 1163 | check_v8086_mode(regs, address, tsk); |
| 1164 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1165 | up_read(&mm->mmap_sem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1166 | } |