diff options
author | Vegard Nossum <vegard.nossum@gmail.com> | 2008-04-03 18:51:41 -0400 |
---|---|---|
committer | Vegard Nossum <vegard.nossum@gmail.com> | 2009-06-13 09:37:30 -0400 |
commit | dfec072ecd35ba6ecad2d51dde325253ac9a2936 (patch) | |
tree | ccf682a631ef8edc0675d68d004bc3a80b34b648 /arch | |
parent | e594c8de3bd4e7732ed3340fb01e18ec94b12df2 (diff) |
kmemcheck: add the kmemcheck core
General description: kmemcheck is a patch to the linux kernel that
detects use of uninitialized memory. It does this by trapping every
read and write to memory that was allocated dynamically (e.g. using
kmalloc()). If a memory address is read that has not previously been
written to, a message is printed to the kernel log.
Thanks to Andi Kleen for the set_memory_4k() solution.
Andrew Morton suggested documenting the shadow member of struct page.
Signed-off-by: Vegard Nossum <vegardno@ifi.uio.no>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
[export kmemcheck_mark_initialized]
[build fix for setup_max_cpus]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegardno@ifi.uio.no>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/x86/Makefile | 5 | ||||
-rw-r--r-- | arch/x86/include/asm/kmemcheck.h | 42 | ||||
-rw-r--r-- | arch/x86/include/asm/pgtable.h | 9 | ||||
-rw-r--r-- | arch/x86/include/asm/pgtable_types.h | 4 | ||||
-rw-r--r-- | arch/x86/mm/Makefile | 2 | ||||
-rw-r--r-- | arch/x86/mm/kmemcheck/Makefile | 1 | ||||
-rw-r--r-- | arch/x86/mm/kmemcheck/error.c | 229 | ||||
-rw-r--r-- | arch/x86/mm/kmemcheck/error.h | 15 | ||||
-rw-r--r-- | arch/x86/mm/kmemcheck/kmemcheck.c | 650 | ||||
-rw-r--r-- | arch/x86/mm/kmemcheck/opcode.c | 101 | ||||
-rw-r--r-- | arch/x86/mm/kmemcheck/opcode.h | 9 | ||||
-rw-r--r-- | arch/x86/mm/kmemcheck/pte.c | 22 | ||||
-rw-r--r-- | arch/x86/mm/kmemcheck/pte.h | 10 | ||||
-rw-r--r-- | arch/x86/mm/kmemcheck/shadow.c | 153 | ||||
-rw-r--r-- | arch/x86/mm/kmemcheck/shadow.h | 16 |
15 files changed, 1266 insertions, 2 deletions
diff --git a/arch/x86/Makefile b/arch/x86/Makefile index edbd0ca62067..1b68659c41b4 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile | |||
@@ -81,6 +81,11 @@ ifdef CONFIG_CC_STACKPROTECTOR | |||
81 | endif | 81 | endif |
82 | endif | 82 | endif |
83 | 83 | ||
84 | # Don't unroll struct assignments with kmemcheck enabled | ||
85 | ifeq ($(CONFIG_KMEMCHECK),y) | ||
86 | KBUILD_CFLAGS += $(call cc-option,-fno-builtin-memcpy) | ||
87 | endif | ||
88 | |||
84 | # Stackpointer is addressed different for 32 bit and 64 bit x86 | 89 | # Stackpointer is addressed different for 32 bit and 64 bit x86 |
85 | sp-$(CONFIG_X86_32) := esp | 90 | sp-$(CONFIG_X86_32) := esp |
86 | sp-$(CONFIG_X86_64) := rsp | 91 | sp-$(CONFIG_X86_64) := rsp |
diff --git a/arch/x86/include/asm/kmemcheck.h b/arch/x86/include/asm/kmemcheck.h new file mode 100644 index 000000000000..ed01518f297e --- /dev/null +++ b/arch/x86/include/asm/kmemcheck.h | |||
@@ -0,0 +1,42 @@ | |||
1 | #ifndef ASM_X86_KMEMCHECK_H | ||
2 | #define ASM_X86_KMEMCHECK_H | ||
3 | |||
4 | #include <linux/types.h> | ||
5 | #include <asm/ptrace.h> | ||
6 | |||
7 | #ifdef CONFIG_KMEMCHECK | ||
8 | bool kmemcheck_active(struct pt_regs *regs); | ||
9 | |||
10 | void kmemcheck_show(struct pt_regs *regs); | ||
11 | void kmemcheck_hide(struct pt_regs *regs); | ||
12 | |||
13 | bool kmemcheck_fault(struct pt_regs *regs, | ||
14 | unsigned long address, unsigned long error_code); | ||
15 | bool kmemcheck_trap(struct pt_regs *regs); | ||
16 | #else | ||
17 | static inline bool kmemcheck_active(struct pt_regs *regs) | ||
18 | { | ||
19 | return false; | ||
20 | } | ||
21 | |||
22 | static inline void kmemcheck_show(struct pt_regs *regs) | ||
23 | { | ||
24 | } | ||
25 | |||
26 | static inline void kmemcheck_hide(struct pt_regs *regs) | ||
27 | { | ||
28 | } | ||
29 | |||
30 | static inline bool kmemcheck_fault(struct pt_regs *regs, | ||
31 | unsigned long address, unsigned long error_code) | ||
32 | { | ||
33 | return false; | ||
34 | } | ||
35 | |||
36 | static inline bool kmemcheck_trap(struct pt_regs *regs) | ||
37 | { | ||
38 | return false; | ||
39 | } | ||
40 | #endif /* CONFIG_KMEMCHECK */ | ||
41 | |||
42 | #endif | ||
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 18ef7ebf2631..c5a08079ad5e 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h | |||
@@ -317,6 +317,15 @@ static inline int pte_present(pte_t a) | |||
317 | return pte_flags(a) & (_PAGE_PRESENT | _PAGE_PROTNONE); | 317 | return pte_flags(a) & (_PAGE_PRESENT | _PAGE_PROTNONE); |
318 | } | 318 | } |
319 | 319 | ||
320 | static inline int pte_hidden(pte_t x) | ||
321 | { | ||
322 | #ifdef CONFIG_KMEMCHECK | ||
323 | return pte_flags(x) & _PAGE_HIDDEN; | ||
324 | #else | ||
325 | return 0; | ||
326 | #endif | ||
327 | } | ||
328 | |||
320 | static inline int pmd_present(pmd_t pmd) | 329 | static inline int pmd_present(pmd_t pmd) |
321 | { | 330 | { |
322 | return pmd_flags(pmd) & _PAGE_PRESENT; | 331 | return pmd_flags(pmd) & _PAGE_PRESENT; |
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h index 4d258ad76a0f..9b5c92140aab 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h | |||
@@ -18,7 +18,7 @@ | |||
18 | #define _PAGE_BIT_GLOBAL 8 /* Global TLB entry PPro+ */ | 18 | #define _PAGE_BIT_GLOBAL 8 /* Global TLB entry PPro+ */ |
19 | #define _PAGE_BIT_UNUSED1 9 /* available for programmer */ | 19 | #define _PAGE_BIT_UNUSED1 9 /* available for programmer */ |
20 | #define _PAGE_BIT_IOMAP 10 /* flag used to indicate IO mapping */ | 20 | #define _PAGE_BIT_IOMAP 10 /* flag used to indicate IO mapping */ |
21 | #define _PAGE_BIT_UNUSED3 11 | 21 | #define _PAGE_BIT_HIDDEN 11 /* hidden by kmemcheck */ |
22 | #define _PAGE_BIT_PAT_LARGE 12 /* On 2MB or 1GB pages */ | 22 | #define _PAGE_BIT_PAT_LARGE 12 /* On 2MB or 1GB pages */ |
23 | #define _PAGE_BIT_SPECIAL _PAGE_BIT_UNUSED1 | 23 | #define _PAGE_BIT_SPECIAL _PAGE_BIT_UNUSED1 |
24 | #define _PAGE_BIT_CPA_TEST _PAGE_BIT_UNUSED1 | 24 | #define _PAGE_BIT_CPA_TEST _PAGE_BIT_UNUSED1 |
@@ -41,7 +41,7 @@ | |||
41 | #define _PAGE_GLOBAL (_AT(pteval_t, 1) << _PAGE_BIT_GLOBAL) | 41 | #define _PAGE_GLOBAL (_AT(pteval_t, 1) << _PAGE_BIT_GLOBAL) |
42 | #define _PAGE_UNUSED1 (_AT(pteval_t, 1) << _PAGE_BIT_UNUSED1) | 42 | #define _PAGE_UNUSED1 (_AT(pteval_t, 1) << _PAGE_BIT_UNUSED1) |
43 | #define _PAGE_IOMAP (_AT(pteval_t, 1) << _PAGE_BIT_IOMAP) | 43 | #define _PAGE_IOMAP (_AT(pteval_t, 1) << _PAGE_BIT_IOMAP) |
44 | #define _PAGE_UNUSED3 (_AT(pteval_t, 1) << _PAGE_BIT_UNUSED3) | 44 | #define _PAGE_HIDDEN (_AT(pteval_t, 1) << _PAGE_BIT_HIDDEN) |
45 | #define _PAGE_PAT (_AT(pteval_t, 1) << _PAGE_BIT_PAT) | 45 | #define _PAGE_PAT (_AT(pteval_t, 1) << _PAGE_BIT_PAT) |
46 | #define _PAGE_PAT_LARGE (_AT(pteval_t, 1) << _PAGE_BIT_PAT_LARGE) | 46 | #define _PAGE_PAT_LARGE (_AT(pteval_t, 1) << _PAGE_BIT_PAT_LARGE) |
47 | #define _PAGE_SPECIAL (_AT(pteval_t, 1) << _PAGE_BIT_SPECIAL) | 47 | #define _PAGE_SPECIAL (_AT(pteval_t, 1) << _PAGE_BIT_SPECIAL) |
diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile index fdd30d08ab52..eefdeee8a871 100644 --- a/arch/x86/mm/Makefile +++ b/arch/x86/mm/Makefile | |||
@@ -10,6 +10,8 @@ obj-$(CONFIG_X86_PTDUMP) += dump_pagetables.o | |||
10 | 10 | ||
11 | obj-$(CONFIG_HIGHMEM) += highmem_32.o | 11 | obj-$(CONFIG_HIGHMEM) += highmem_32.o |
12 | 12 | ||
13 | obj-$(CONFIG_KMEMCHECK) += kmemcheck/ | ||
14 | |||
13 | obj-$(CONFIG_MMIOTRACE) += mmiotrace.o | 15 | obj-$(CONFIG_MMIOTRACE) += mmiotrace.o |
14 | mmiotrace-y := kmmio.o pf_in.o mmio-mod.o | 16 | mmiotrace-y := kmmio.o pf_in.o mmio-mod.o |
15 | obj-$(CONFIG_MMIOTRACE_TEST) += testmmiotrace.o | 17 | obj-$(CONFIG_MMIOTRACE_TEST) += testmmiotrace.o |
diff --git a/arch/x86/mm/kmemcheck/Makefile b/arch/x86/mm/kmemcheck/Makefile new file mode 100644 index 000000000000..4666b7a778be --- /dev/null +++ b/arch/x86/mm/kmemcheck/Makefile | |||
@@ -0,0 +1 @@ | |||
obj-y := error.o kmemcheck.o opcode.o pte.o shadow.o | |||
diff --git a/arch/x86/mm/kmemcheck/error.c b/arch/x86/mm/kmemcheck/error.c new file mode 100644 index 000000000000..5ec9f5a93f47 --- /dev/null +++ b/arch/x86/mm/kmemcheck/error.c | |||
@@ -0,0 +1,229 @@ | |||
1 | #include <linux/interrupt.h> | ||
2 | #include <linux/kdebug.h> | ||
3 | #include <linux/kmemcheck.h> | ||
4 | #include <linux/kernel.h> | ||
5 | #include <linux/types.h> | ||
6 | #include <linux/ptrace.h> | ||
7 | #include <linux/stacktrace.h> | ||
8 | #include <linux/string.h> | ||
9 | |||
10 | #include "error.h" | ||
11 | #include "shadow.h" | ||
12 | |||
13 | enum kmemcheck_error_type { | ||
14 | KMEMCHECK_ERROR_INVALID_ACCESS, | ||
15 | KMEMCHECK_ERROR_BUG, | ||
16 | }; | ||
17 | |||
18 | #define SHADOW_COPY_SIZE (1 << CONFIG_KMEMCHECK_SHADOW_COPY_SHIFT) | ||
19 | |||
20 | struct kmemcheck_error { | ||
21 | enum kmemcheck_error_type type; | ||
22 | |||
23 | union { | ||
24 | /* KMEMCHECK_ERROR_INVALID_ACCESS */ | ||
25 | struct { | ||
26 | /* Kind of access that caused the error */ | ||
27 | enum kmemcheck_shadow state; | ||
28 | /* Address and size of the erroneous read */ | ||
29 | unsigned long address; | ||
30 | unsigned int size; | ||
31 | }; | ||
32 | }; | ||
33 | |||
34 | struct pt_regs regs; | ||
35 | struct stack_trace trace; | ||
36 | unsigned long trace_entries[32]; | ||
37 | |||
38 | /* We compress it to a char. */ | ||
39 | unsigned char shadow_copy[SHADOW_COPY_SIZE]; | ||
40 | unsigned char memory_copy[SHADOW_COPY_SIZE]; | ||
41 | }; | ||
42 | |||
43 | /* | ||
44 | * Create a ring queue of errors to output. We can't call printk() directly | ||
45 | * from the kmemcheck traps, since this may call the console drivers and | ||
46 | * result in a recursive fault. | ||
47 | */ | ||
48 | static struct kmemcheck_error error_fifo[CONFIG_KMEMCHECK_QUEUE_SIZE]; | ||
49 | static unsigned int error_count; | ||
50 | static unsigned int error_rd; | ||
51 | static unsigned int error_wr; | ||
52 | static unsigned int error_missed_count; | ||
53 | |||
54 | static struct kmemcheck_error *error_next_wr(void) | ||
55 | { | ||
56 | struct kmemcheck_error *e; | ||
57 | |||
58 | if (error_count == ARRAY_SIZE(error_fifo)) { | ||
59 | ++error_missed_count; | ||
60 | return NULL; | ||
61 | } | ||
62 | |||
63 | e = &error_fifo[error_wr]; | ||
64 | if (++error_wr == ARRAY_SIZE(error_fifo)) | ||
65 | error_wr = 0; | ||
66 | ++error_count; | ||
67 | return e; | ||
68 | } | ||
69 | |||
70 | static struct kmemcheck_error *error_next_rd(void) | ||
71 | { | ||
72 | struct kmemcheck_error *e; | ||
73 | |||
74 | if (error_count == 0) | ||
75 | return NULL; | ||
76 | |||
77 | e = &error_fifo[error_rd]; | ||
78 | if (++error_rd == ARRAY_SIZE(error_fifo)) | ||
79 | error_rd = 0; | ||
80 | --error_count; | ||
81 | return e; | ||
82 | } | ||
83 | |||
84 | static void do_wakeup(unsigned long); | ||
85 | static DECLARE_TASKLET(kmemcheck_tasklet, &do_wakeup, 0); | ||
86 | |||
87 | /* | ||
88 | * Save the context of an error report. | ||
89 | */ | ||
90 | void kmemcheck_error_save(enum kmemcheck_shadow state, | ||
91 | unsigned long address, unsigned int size, struct pt_regs *regs) | ||
92 | { | ||
93 | static unsigned long prev_ip; | ||
94 | |||
95 | struct kmemcheck_error *e; | ||
96 | void *shadow_copy; | ||
97 | void *memory_copy; | ||
98 | |||
99 | /* Don't report several adjacent errors from the same EIP. */ | ||
100 | if (regs->ip == prev_ip) | ||
101 | return; | ||
102 | prev_ip = regs->ip; | ||
103 | |||
104 | e = error_next_wr(); | ||
105 | if (!e) | ||
106 | return; | ||
107 | |||
108 | e->type = KMEMCHECK_ERROR_INVALID_ACCESS; | ||
109 | |||
110 | e->state = state; | ||
111 | e->address = address; | ||
112 | e->size = size; | ||
113 | |||
114 | /* Save regs */ | ||
115 | memcpy(&e->regs, regs, sizeof(*regs)); | ||
116 | |||
117 | /* Save stack trace */ | ||
118 | e->trace.nr_entries = 0; | ||
119 | e->trace.entries = e->trace_entries; | ||
120 | e->trace.max_entries = ARRAY_SIZE(e->trace_entries); | ||
121 | e->trace.skip = 0; | ||
122 | save_stack_trace_bp(&e->trace, regs->bp); | ||
123 | |||
124 | /* Round address down to nearest 16 bytes */ | ||
125 | shadow_copy = kmemcheck_shadow_lookup(address | ||
126 | & ~(SHADOW_COPY_SIZE - 1)); | ||
127 | BUG_ON(!shadow_copy); | ||
128 | |||
129 | memcpy(e->shadow_copy, shadow_copy, SHADOW_COPY_SIZE); | ||
130 | |||
131 | kmemcheck_show_addr(address); | ||
132 | memory_copy = (void *) (address & ~(SHADOW_COPY_SIZE - 1)); | ||
133 | memcpy(e->memory_copy, memory_copy, SHADOW_COPY_SIZE); | ||
134 | kmemcheck_hide_addr(address); | ||
135 | |||
136 | tasklet_hi_schedule_first(&kmemcheck_tasklet); | ||
137 | } | ||
138 | |||
139 | /* | ||
140 | * Save the context of a kmemcheck bug. | ||
141 | */ | ||
142 | void kmemcheck_error_save_bug(struct pt_regs *regs) | ||
143 | { | ||
144 | struct kmemcheck_error *e; | ||
145 | |||
146 | e = error_next_wr(); | ||
147 | if (!e) | ||
148 | return; | ||
149 | |||
150 | e->type = KMEMCHECK_ERROR_BUG; | ||
151 | |||
152 | memcpy(&e->regs, regs, sizeof(*regs)); | ||
153 | |||
154 | e->trace.nr_entries = 0; | ||
155 | e->trace.entries = e->trace_entries; | ||
156 | e->trace.max_entries = ARRAY_SIZE(e->trace_entries); | ||
157 | e->trace.skip = 1; | ||
158 | save_stack_trace(&e->trace); | ||
159 | |||
160 | tasklet_hi_schedule_first(&kmemcheck_tasklet); | ||
161 | } | ||
162 | |||
163 | void kmemcheck_error_recall(void) | ||
164 | { | ||
165 | static const char *desc[] = { | ||
166 | [KMEMCHECK_SHADOW_UNALLOCATED] = "unallocated", | ||
167 | [KMEMCHECK_SHADOW_UNINITIALIZED] = "uninitialized", | ||
168 | [KMEMCHECK_SHADOW_INITIALIZED] = "initialized", | ||
169 | [KMEMCHECK_SHADOW_FREED] = "freed", | ||
170 | }; | ||
171 | |||
172 | static const char short_desc[] = { | ||
173 | [KMEMCHECK_SHADOW_UNALLOCATED] = 'a', | ||
174 | [KMEMCHECK_SHADOW_UNINITIALIZED] = 'u', | ||
175 | [KMEMCHECK_SHADOW_INITIALIZED] = 'i', | ||
176 | [KMEMCHECK_SHADOW_FREED] = 'f', | ||
177 | }; | ||
178 | |||
179 | struct kmemcheck_error *e; | ||
180 | unsigned int i; | ||
181 | |||
182 | e = error_next_rd(); | ||
183 | if (!e) | ||
184 | return; | ||
185 | |||
186 | switch (e->type) { | ||
187 | case KMEMCHECK_ERROR_INVALID_ACCESS: | ||
188 | printk(KERN_ERR "WARNING: kmemcheck: Caught %d-bit read " | ||
189 | "from %s memory (%p)\n", | ||
190 | 8 * e->size, e->state < ARRAY_SIZE(desc) ? | ||
191 | desc[e->state] : "(invalid shadow state)", | ||
192 | (void *) e->address); | ||
193 | |||
194 | printk(KERN_INFO); | ||
195 | for (i = 0; i < SHADOW_COPY_SIZE; ++i) | ||
196 | printk("%02x", e->memory_copy[i]); | ||
197 | printk("\n"); | ||
198 | |||
199 | printk(KERN_INFO); | ||
200 | for (i = 0; i < SHADOW_COPY_SIZE; ++i) { | ||
201 | if (e->shadow_copy[i] < ARRAY_SIZE(short_desc)) | ||
202 | printk(" %c", short_desc[e->shadow_copy[i]]); | ||
203 | else | ||
204 | printk(" ?"); | ||
205 | } | ||
206 | printk("\n"); | ||
207 | printk(KERN_INFO "%*c\n", 2 + 2 | ||
208 | * (int) (e->address & (SHADOW_COPY_SIZE - 1)), '^'); | ||
209 | break; | ||
210 | case KMEMCHECK_ERROR_BUG: | ||
211 | printk(KERN_EMERG "ERROR: kmemcheck: Fatal error\n"); | ||
212 | break; | ||
213 | } | ||
214 | |||
215 | __show_regs(&e->regs, 1); | ||
216 | print_stack_trace(&e->trace, 0); | ||
217 | } | ||
218 | |||
219 | static void do_wakeup(unsigned long data) | ||
220 | { | ||
221 | while (error_count > 0) | ||
222 | kmemcheck_error_recall(); | ||
223 | |||
224 | if (error_missed_count > 0) { | ||
225 | printk(KERN_WARNING "kmemcheck: Lost %d error reports because " | ||
226 | "the queue was too small\n", error_missed_count); | ||
227 | error_missed_count = 0; | ||
228 | } | ||
229 | } | ||
diff --git a/arch/x86/mm/kmemcheck/error.h b/arch/x86/mm/kmemcheck/error.h new file mode 100644 index 000000000000..0efc2e8d0a20 --- /dev/null +++ b/arch/x86/mm/kmemcheck/error.h | |||
@@ -0,0 +1,15 @@ | |||
1 | #ifndef ARCH__X86__MM__KMEMCHECK__ERROR_H | ||
2 | #define ARCH__X86__MM__KMEMCHECK__ERROR_H | ||
3 | |||
4 | #include <linux/ptrace.h> | ||
5 | |||
6 | #include "shadow.h" | ||
7 | |||
8 | void kmemcheck_error_save(enum kmemcheck_shadow state, | ||
9 | unsigned long address, unsigned int size, struct pt_regs *regs); | ||
10 | |||
11 | void kmemcheck_error_save_bug(struct pt_regs *regs); | ||
12 | |||
13 | void kmemcheck_error_recall(void); | ||
14 | |||
15 | #endif | ||
diff --git a/arch/x86/mm/kmemcheck/kmemcheck.c b/arch/x86/mm/kmemcheck/kmemcheck.c new file mode 100644 index 000000000000..9de7d8f6b6e1 --- /dev/null +++ b/arch/x86/mm/kmemcheck/kmemcheck.c | |||
@@ -0,0 +1,650 @@ | |||
1 | /** | ||
2 | * kmemcheck - a heavyweight memory checker for the linux kernel | ||
3 | * Copyright (C) 2007, 2008 Vegard Nossum <vegardno@ifi.uio.no> | ||
4 | * (With a lot of help from Ingo Molnar and Pekka Enberg.) | ||
5 | * | ||
6 | * This program is free software; you can redistribute it and/or modify | ||
7 | * it under the terms of the GNU General Public License (version 2) as | ||
8 | * published by the Free Software Foundation. | ||
9 | */ | ||
10 | |||
11 | #include <linux/init.h> | ||
12 | #include <linux/interrupt.h> | ||
13 | #include <linux/kallsyms.h> | ||
14 | #include <linux/kernel.h> | ||
15 | #include <linux/kmemcheck.h> | ||
16 | #include <linux/mm.h> | ||
17 | #include <linux/module.h> | ||
18 | #include <linux/page-flags.h> | ||
19 | #include <linux/percpu.h> | ||
20 | #include <linux/ptrace.h> | ||
21 | #include <linux/string.h> | ||
22 | #include <linux/types.h> | ||
23 | |||
24 | #include <asm/cacheflush.h> | ||
25 | #include <asm/kmemcheck.h> | ||
26 | #include <asm/pgtable.h> | ||
27 | #include <asm/tlbflush.h> | ||
28 | |||
29 | #include "error.h" | ||
30 | #include "opcode.h" | ||
31 | #include "pte.h" | ||
32 | #include "shadow.h" | ||
33 | |||
34 | #ifdef CONFIG_KMEMCHECK_DISABLED_BY_DEFAULT | ||
35 | # define KMEMCHECK_ENABLED 0 | ||
36 | #endif | ||
37 | |||
38 | #ifdef CONFIG_KMEMCHECK_ENABLED_BY_DEFAULT | ||
39 | # define KMEMCHECK_ENABLED 1 | ||
40 | #endif | ||
41 | |||
42 | #ifdef CONFIG_KMEMCHECK_ONESHOT_BY_DEFAULT | ||
43 | # define KMEMCHECK_ENABLED 2 | ||
44 | #endif | ||
45 | |||
46 | int kmemcheck_enabled = KMEMCHECK_ENABLED; | ||
47 | |||
48 | int __init kmemcheck_init(void) | ||
49 | { | ||
50 | printk(KERN_INFO "kmemcheck: \"Bugs, beware!\"\n"); | ||
51 | |||
52 | #ifdef CONFIG_SMP | ||
53 | /* | ||
54 | * Limit SMP to use a single CPU. We rely on the fact that this code | ||
55 | * runs before SMP is set up. | ||
56 | */ | ||
57 | if (setup_max_cpus > 1) { | ||
58 | printk(KERN_INFO | ||
59 | "kmemcheck: Limiting number of CPUs to 1.\n"); | ||
60 | setup_max_cpus = 1; | ||
61 | } | ||
62 | #endif | ||
63 | |||
64 | return 0; | ||
65 | } | ||
66 | |||
67 | early_initcall(kmemcheck_init); | ||
68 | |||
69 | #ifdef CONFIG_KMEMCHECK_DISABLED_BY_DEFAULT | ||
70 | int kmemcheck_enabled = 0; | ||
71 | #endif | ||
72 | |||
73 | #ifdef CONFIG_KMEMCHECK_ENABLED_BY_DEFAULT | ||
74 | int kmemcheck_enabled = 1; | ||
75 | #endif | ||
76 | |||
77 | #ifdef CONFIG_KMEMCHECK_ONESHOT_BY_DEFAULT | ||
78 | int kmemcheck_enabled = 2; | ||
79 | #endif | ||
80 | |||
81 | /* | ||
82 | * We need to parse the kmemcheck= option before any memory is allocated. | ||
83 | */ | ||
84 | static int __init param_kmemcheck(char *str) | ||
85 | { | ||
86 | if (!str) | ||
87 | return -EINVAL; | ||
88 | |||
89 | sscanf(str, "%d", &kmemcheck_enabled); | ||
90 | return 0; | ||
91 | } | ||
92 | |||
93 | early_param("kmemcheck", param_kmemcheck); | ||
94 | |||
95 | int kmemcheck_show_addr(unsigned long address) | ||
96 | { | ||
97 | pte_t *pte; | ||
98 | |||
99 | pte = kmemcheck_pte_lookup(address); | ||
100 | if (!pte) | ||
101 | return 0; | ||
102 | |||
103 | set_pte(pte, __pte(pte_val(*pte) | _PAGE_PRESENT)); | ||
104 | __flush_tlb_one(address); | ||
105 | return 1; | ||
106 | } | ||
107 | |||
108 | int kmemcheck_hide_addr(unsigned long address) | ||
109 | { | ||
110 | pte_t *pte; | ||
111 | |||
112 | pte = kmemcheck_pte_lookup(address); | ||
113 | if (!pte) | ||
114 | return 0; | ||
115 | |||
116 | set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_PRESENT)); | ||
117 | __flush_tlb_one(address); | ||
118 | return 1; | ||
119 | } | ||
120 | |||
121 | struct kmemcheck_context { | ||
122 | bool busy; | ||
123 | int balance; | ||
124 | |||
125 | /* | ||
126 | * There can be at most two memory operands to an instruction, but | ||
127 | * each address can cross a page boundary -- so we may need up to | ||
128 | * four addresses that must be hidden/revealed for each fault. | ||
129 | */ | ||
130 | unsigned long addr[4]; | ||
131 | unsigned long n_addrs; | ||
132 | unsigned long flags; | ||
133 | |||
134 | /* Data size of the instruction that caused a fault. */ | ||
135 | unsigned int size; | ||
136 | }; | ||
137 | |||
138 | static DEFINE_PER_CPU(struct kmemcheck_context, kmemcheck_context); | ||
139 | |||
140 | bool kmemcheck_active(struct pt_regs *regs) | ||
141 | { | ||
142 | struct kmemcheck_context *data = &__get_cpu_var(kmemcheck_context); | ||
143 | |||
144 | return data->balance > 0; | ||
145 | } | ||
146 | |||
147 | /* Save an address that needs to be shown/hidden */ | ||
148 | static void kmemcheck_save_addr(unsigned long addr) | ||
149 | { | ||
150 | struct kmemcheck_context *data = &__get_cpu_var(kmemcheck_context); | ||
151 | |||
152 | BUG_ON(data->n_addrs >= ARRAY_SIZE(data->addr)); | ||
153 | data->addr[data->n_addrs++] = addr; | ||
154 | } | ||
155 | |||
156 | static unsigned int kmemcheck_show_all(void) | ||
157 | { | ||
158 | struct kmemcheck_context *data = &__get_cpu_var(kmemcheck_context); | ||
159 | unsigned int i; | ||
160 | unsigned int n; | ||
161 | |||
162 | n = 0; | ||
163 | for (i = 0; i < data->n_addrs; ++i) | ||
164 | n += kmemcheck_show_addr(data->addr[i]); | ||
165 | |||
166 | return n; | ||
167 | } | ||
168 | |||
169 | static unsigned int kmemcheck_hide_all(void) | ||
170 | { | ||
171 | struct kmemcheck_context *data = &__get_cpu_var(kmemcheck_context); | ||
172 | unsigned int i; | ||
173 | unsigned int n; | ||
174 | |||
175 | n = 0; | ||
176 | for (i = 0; i < data->n_addrs; ++i) | ||
177 | n += kmemcheck_hide_addr(data->addr[i]); | ||
178 | |||
179 | return n; | ||
180 | } | ||
181 | |||
182 | /* | ||
183 | * Called from the #PF handler. | ||
184 | */ | ||
185 | void kmemcheck_show(struct pt_regs *regs) | ||
186 | { | ||
187 | struct kmemcheck_context *data = &__get_cpu_var(kmemcheck_context); | ||
188 | |||
189 | BUG_ON(!irqs_disabled()); | ||
190 | |||
191 | if (unlikely(data->balance != 0)) { | ||
192 | kmemcheck_show_all(); | ||
193 | kmemcheck_error_save_bug(regs); | ||
194 | data->balance = 0; | ||
195 | return; | ||
196 | } | ||
197 | |||
198 | /* | ||
199 | * None of the addresses actually belonged to kmemcheck. Note that | ||
200 | * this is not an error. | ||
201 | */ | ||
202 | if (kmemcheck_show_all() == 0) | ||
203 | return; | ||
204 | |||
205 | ++data->balance; | ||
206 | |||
207 | /* | ||
208 | * The IF needs to be cleared as well, so that the faulting | ||
209 | * instruction can run "uninterrupted". Otherwise, we might take | ||
210 | * an interrupt and start executing that before we've had a chance | ||
211 | * to hide the page again. | ||
212 | * | ||
213 | * NOTE: In the rare case of multiple faults, we must not override | ||
214 | * the original flags: | ||
215 | */ | ||
216 | if (!(regs->flags & X86_EFLAGS_TF)) | ||
217 | data->flags = regs->flags; | ||
218 | |||
219 | regs->flags |= X86_EFLAGS_TF; | ||
220 | regs->flags &= ~X86_EFLAGS_IF; | ||
221 | } | ||
222 | |||
223 | /* | ||
224 | * Called from the #DB handler. | ||
225 | */ | ||
226 | void kmemcheck_hide(struct pt_regs *regs) | ||
227 | { | ||
228 | struct kmemcheck_context *data = &__get_cpu_var(kmemcheck_context); | ||
229 | int n; | ||
230 | |||
231 | BUG_ON(!irqs_disabled()); | ||
232 | |||
233 | if (data->balance == 0) | ||
234 | return; | ||
235 | |||
236 | if (unlikely(data->balance != 1)) { | ||
237 | kmemcheck_show_all(); | ||
238 | kmemcheck_error_save_bug(regs); | ||
239 | data->n_addrs = 0; | ||
240 | data->balance = 0; | ||
241 | |||
242 | if (!(data->flags & X86_EFLAGS_TF)) | ||
243 | regs->flags &= ~X86_EFLAGS_TF; | ||
244 | if (data->flags & X86_EFLAGS_IF) | ||
245 | regs->flags |= X86_EFLAGS_IF; | ||
246 | return; | ||
247 | } | ||
248 | |||
249 | if (kmemcheck_enabled) | ||
250 | n = kmemcheck_hide_all(); | ||
251 | else | ||
252 | n = kmemcheck_show_all(); | ||
253 | |||
254 | if (n == 0) | ||
255 | return; | ||
256 | |||
257 | --data->balance; | ||
258 | |||
259 | data->n_addrs = 0; | ||
260 | |||
261 | if (!(data->flags & X86_EFLAGS_TF)) | ||
262 | regs->flags &= ~X86_EFLAGS_TF; | ||
263 | if (data->flags & X86_EFLAGS_IF) | ||
264 | regs->flags |= X86_EFLAGS_IF; | ||
265 | } | ||
266 | |||
267 | void kmemcheck_show_pages(struct page *p, unsigned int n) | ||
268 | { | ||
269 | unsigned int i; | ||
270 | |||
271 | for (i = 0; i < n; ++i) { | ||
272 | unsigned long address; | ||
273 | pte_t *pte; | ||
274 | unsigned int level; | ||
275 | |||
276 | address = (unsigned long) page_address(&p[i]); | ||
277 | pte = lookup_address(address, &level); | ||
278 | BUG_ON(!pte); | ||
279 | BUG_ON(level != PG_LEVEL_4K); | ||
280 | |||
281 | set_pte(pte, __pte(pte_val(*pte) | _PAGE_PRESENT)); | ||
282 | set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_HIDDEN)); | ||
283 | __flush_tlb_one(address); | ||
284 | } | ||
285 | } | ||
286 | |||
287 | bool kmemcheck_page_is_tracked(struct page *p) | ||
288 | { | ||
289 | /* This will also check the "hidden" flag of the PTE. */ | ||
290 | return kmemcheck_pte_lookup((unsigned long) page_address(p)); | ||
291 | } | ||
292 | |||
293 | void kmemcheck_hide_pages(struct page *p, unsigned int n) | ||
294 | { | ||
295 | unsigned int i; | ||
296 | |||
297 | for (i = 0; i < n; ++i) { | ||
298 | unsigned long address; | ||
299 | pte_t *pte; | ||
300 | unsigned int level; | ||
301 | |||
302 | address = (unsigned long) page_address(&p[i]); | ||
303 | pte = lookup_address(address, &level); | ||
304 | BUG_ON(!pte); | ||
305 | BUG_ON(level != PG_LEVEL_4K); | ||
306 | |||
307 | set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_PRESENT)); | ||
308 | set_pte(pte, __pte(pte_val(*pte) | _PAGE_HIDDEN)); | ||
309 | __flush_tlb_one(address); | ||
310 | } | ||
311 | } | ||
312 | |||
313 | /* Access may NOT cross page boundary */ | ||
314 | static void kmemcheck_read_strict(struct pt_regs *regs, | ||
315 | unsigned long addr, unsigned int size) | ||
316 | { | ||
317 | void *shadow; | ||
318 | enum kmemcheck_shadow status; | ||
319 | |||
320 | shadow = kmemcheck_shadow_lookup(addr); | ||
321 | if (!shadow) | ||
322 | return; | ||
323 | |||
324 | kmemcheck_save_addr(addr); | ||
325 | status = kmemcheck_shadow_test(shadow, size); | ||
326 | if (status == KMEMCHECK_SHADOW_INITIALIZED) | ||
327 | return; | ||
328 | |||
329 | if (kmemcheck_enabled) | ||
330 | kmemcheck_error_save(status, addr, size, regs); | ||
331 | |||
332 | if (kmemcheck_enabled == 2) | ||
333 | kmemcheck_enabled = 0; | ||
334 | |||
335 | /* Don't warn about it again. */ | ||
336 | kmemcheck_shadow_set(shadow, size); | ||
337 | } | ||
338 | |||
339 | /* Access may cross page boundary */ | ||
340 | static void kmemcheck_read(struct pt_regs *regs, | ||
341 | unsigned long addr, unsigned int size) | ||
342 | { | ||
343 | unsigned long page = addr & PAGE_MASK; | ||
344 | unsigned long next_addr = addr + size - 1; | ||
345 | unsigned long next_page = next_addr & PAGE_MASK; | ||
346 | |||
347 | if (likely(page == next_page)) { | ||
348 | kmemcheck_read_strict(regs, addr, size); | ||
349 | return; | ||
350 | } | ||
351 | |||
352 | /* | ||
353 | * What we do is basically to split the access across the | ||
354 | * two pages and handle each part separately. Yes, this means | ||
355 | * that we may now see reads that are 3 + 5 bytes, for | ||
356 | * example (and if both are uninitialized, there will be two | ||
357 | * reports), but it makes the code a lot simpler. | ||
358 | */ | ||
359 | kmemcheck_read_strict(regs, addr, next_page - addr); | ||
360 | kmemcheck_read_strict(regs, next_page, next_addr - next_page); | ||
361 | } | ||
362 | |||
363 | static void kmemcheck_write_strict(struct pt_regs *regs, | ||
364 | unsigned long addr, unsigned int size) | ||
365 | { | ||
366 | void *shadow; | ||
367 | |||
368 | shadow = kmemcheck_shadow_lookup(addr); | ||
369 | if (!shadow) | ||
370 | return; | ||
371 | |||
372 | kmemcheck_save_addr(addr); | ||
373 | kmemcheck_shadow_set(shadow, size); | ||
374 | } | ||
375 | |||
376 | static void kmemcheck_write(struct pt_regs *regs, | ||
377 | unsigned long addr, unsigned int size) | ||
378 | { | ||
379 | unsigned long page = addr & PAGE_MASK; | ||
380 | unsigned long next_addr = addr + size - 1; | ||
381 | unsigned long next_page = next_addr & PAGE_MASK; | ||
382 | |||
383 | if (likely(page == next_page)) { | ||
384 | kmemcheck_write_strict(regs, addr, size); | ||
385 | return; | ||
386 | } | ||
387 | |||
388 | /* See comment in kmemcheck_read(). */ | ||
389 | kmemcheck_write_strict(regs, addr, next_page - addr); | ||
390 | kmemcheck_write_strict(regs, next_page, next_addr - next_page); | ||
391 | } | ||
392 | |||
393 | /* | ||
394 | * Copying is hard. We have two addresses, each of which may be split across | ||
395 | * a page (and each page will have different shadow addresses). | ||
396 | */ | ||
397 | static void kmemcheck_copy(struct pt_regs *regs, | ||
398 | unsigned long src_addr, unsigned long dst_addr, unsigned int size) | ||
399 | { | ||
400 | uint8_t shadow[8]; | ||
401 | enum kmemcheck_shadow status; | ||
402 | |||
403 | unsigned long page; | ||
404 | unsigned long next_addr; | ||
405 | unsigned long next_page; | ||
406 | |||
407 | uint8_t *x; | ||
408 | unsigned int i; | ||
409 | unsigned int n; | ||
410 | |||
411 | BUG_ON(size > sizeof(shadow)); | ||
412 | |||
413 | page = src_addr & PAGE_MASK; | ||
414 | next_addr = src_addr + size - 1; | ||
415 | next_page = next_addr & PAGE_MASK; | ||
416 | |||
417 | if (likely(page == next_page)) { | ||
418 | /* Same page */ | ||
419 | x = kmemcheck_shadow_lookup(src_addr); | ||
420 | if (x) { | ||
421 | kmemcheck_save_addr(src_addr); | ||
422 | for (i = 0; i < size; ++i) | ||
423 | shadow[i] = x[i]; | ||
424 | } else { | ||
425 | for (i = 0; i < size; ++i) | ||
426 | shadow[i] = KMEMCHECK_SHADOW_INITIALIZED; | ||
427 | } | ||
428 | } else { | ||
429 | n = next_page - src_addr; | ||
430 | BUG_ON(n > sizeof(shadow)); | ||
431 | |||
432 | /* First page */ | ||
433 | x = kmemcheck_shadow_lookup(src_addr); | ||
434 | if (x) { | ||
435 | kmemcheck_save_addr(src_addr); | ||
436 | for (i = 0; i < n; ++i) | ||
437 | shadow[i] = x[i]; | ||
438 | } else { | ||
439 | /* Not tracked */ | ||
440 | for (i = 0; i < n; ++i) | ||
441 | shadow[i] = KMEMCHECK_SHADOW_INITIALIZED; | ||
442 | } | ||
443 | |||
444 | /* Second page */ | ||
445 | x = kmemcheck_shadow_lookup(next_page); | ||
446 | if (x) { | ||
447 | kmemcheck_save_addr(next_page); | ||
448 | for (i = n; i < size; ++i) | ||
449 | shadow[i] = x[i - n]; | ||
450 | } else { | ||
451 | /* Not tracked */ | ||
452 | for (i = n; i < size; ++i) | ||
453 | shadow[i] = KMEMCHECK_SHADOW_INITIALIZED; | ||
454 | } | ||
455 | } | ||
456 | |||
457 | page = dst_addr & PAGE_MASK; | ||
458 | next_addr = dst_addr + size - 1; | ||
459 | next_page = next_addr & PAGE_MASK; | ||
460 | |||
461 | if (likely(page == next_page)) { | ||
462 | /* Same page */ | ||
463 | x = kmemcheck_shadow_lookup(dst_addr); | ||
464 | if (x) { | ||
465 | kmemcheck_save_addr(dst_addr); | ||
466 | for (i = 0; i < size; ++i) { | ||
467 | x[i] = shadow[i]; | ||
468 | shadow[i] = KMEMCHECK_SHADOW_INITIALIZED; | ||
469 | } | ||
470 | } | ||
471 | } else { | ||
472 | n = next_page - dst_addr; | ||
473 | BUG_ON(n > sizeof(shadow)); | ||
474 | |||
475 | /* First page */ | ||
476 | x = kmemcheck_shadow_lookup(dst_addr); | ||
477 | if (x) { | ||
478 | kmemcheck_save_addr(dst_addr); | ||
479 | for (i = 0; i < n; ++i) { | ||
480 | x[i] = shadow[i]; | ||
481 | shadow[i] = KMEMCHECK_SHADOW_INITIALIZED; | ||
482 | } | ||
483 | } | ||
484 | |||
485 | /* Second page */ | ||
486 | x = kmemcheck_shadow_lookup(next_page); | ||
487 | if (x) { | ||
488 | kmemcheck_save_addr(next_page); | ||
489 | for (i = n; i < size; ++i) { | ||
490 | x[i - n] = shadow[i]; | ||
491 | shadow[i] = KMEMCHECK_SHADOW_INITIALIZED; | ||
492 | } | ||
493 | } | ||
494 | } | ||
495 | |||
496 | status = kmemcheck_shadow_test(shadow, size); | ||
497 | if (status == KMEMCHECK_SHADOW_INITIALIZED) | ||
498 | return; | ||
499 | |||
500 | if (kmemcheck_enabled) | ||
501 | kmemcheck_error_save(status, src_addr, size, regs); | ||
502 | |||
503 | if (kmemcheck_enabled == 2) | ||
504 | kmemcheck_enabled = 0; | ||
505 | } | ||
506 | |||
507 | enum kmemcheck_method { | ||
508 | KMEMCHECK_READ, | ||
509 | KMEMCHECK_WRITE, | ||
510 | }; | ||
511 | |||
512 | static void kmemcheck_access(struct pt_regs *regs, | ||
513 | unsigned long fallback_address, enum kmemcheck_method fallback_method) | ||
514 | { | ||
515 | const uint8_t *insn; | ||
516 | const uint8_t *insn_primary; | ||
517 | unsigned int size; | ||
518 | |||
519 | struct kmemcheck_context *data = &__get_cpu_var(kmemcheck_context); | ||
520 | |||
521 | /* Recursive fault -- ouch. */ | ||
522 | if (data->busy) { | ||
523 | kmemcheck_show_addr(fallback_address); | ||
524 | kmemcheck_error_save_bug(regs); | ||
525 | return; | ||
526 | } | ||
527 | |||
528 | data->busy = true; | ||
529 | |||
530 | insn = (const uint8_t *) regs->ip; | ||
531 | insn_primary = kmemcheck_opcode_get_primary(insn); | ||
532 | |||
533 | kmemcheck_opcode_decode(insn, &size); | ||
534 | |||
535 | switch (insn_primary[0]) { | ||
536 | #ifdef CONFIG_KMEMCHECK_BITOPS_OK | ||
537 | /* AND, OR, XOR */ | ||
538 | /* | ||
539 | * Unfortunately, these instructions have to be excluded from | ||
540 | * our regular checking since they access only some (and not | ||
541 | * all) bits. This clears out "bogus" bitfield-access warnings. | ||
542 | */ | ||
543 | case 0x80: | ||
544 | case 0x81: | ||
545 | case 0x82: | ||
546 | case 0x83: | ||
547 | switch ((insn_primary[1] >> 3) & 7) { | ||
548 | /* OR */ | ||
549 | case 1: | ||
550 | /* AND */ | ||
551 | case 4: | ||
552 | /* XOR */ | ||
553 | case 6: | ||
554 | kmemcheck_write(regs, fallback_address, size); | ||
555 | goto out; | ||
556 | |||
557 | /* ADD */ | ||
558 | case 0: | ||
559 | /* ADC */ | ||
560 | case 2: | ||
561 | /* SBB */ | ||
562 | case 3: | ||
563 | /* SUB */ | ||
564 | case 5: | ||
565 | /* CMP */ | ||
566 | case 7: | ||
567 | break; | ||
568 | } | ||
569 | break; | ||
570 | #endif | ||
571 | |||
572 | /* MOVS, MOVSB, MOVSW, MOVSD */ | ||
573 | case 0xa4: | ||
574 | case 0xa5: | ||
575 | /* | ||
576 | * These instructions are special because they take two | ||
577 | * addresses, but we only get one page fault. | ||
578 | */ | ||
579 | kmemcheck_copy(regs, regs->si, regs->di, size); | ||
580 | goto out; | ||
581 | |||
582 | /* CMPS, CMPSB, CMPSW, CMPSD */ | ||
583 | case 0xa6: | ||
584 | case 0xa7: | ||
585 | kmemcheck_read(regs, regs->si, size); | ||
586 | kmemcheck_read(regs, regs->di, size); | ||
587 | goto out; | ||
588 | } | ||
589 | |||
590 | /* | ||
591 | * If the opcode isn't special in any way, we use the data from the | ||
592 | * page fault handler to determine the address and type of memory | ||
593 | * access. | ||
594 | */ | ||
595 | switch (fallback_method) { | ||
596 | case KMEMCHECK_READ: | ||
597 | kmemcheck_read(regs, fallback_address, size); | ||
598 | goto out; | ||
599 | case KMEMCHECK_WRITE: | ||
600 | kmemcheck_write(regs, fallback_address, size); | ||
601 | goto out; | ||
602 | } | ||
603 | |||
604 | out: | ||
605 | data->busy = false; | ||
606 | } | ||
607 | |||
608 | bool kmemcheck_fault(struct pt_regs *regs, unsigned long address, | ||
609 | unsigned long error_code) | ||
610 | { | ||
611 | pte_t *pte; | ||
612 | unsigned int level; | ||
613 | |||
614 | /* | ||
615 | * XXX: Is it safe to assume that memory accesses from virtual 86 | ||
616 | * mode or non-kernel code segments will _never_ access kernel | ||
617 | * memory (e.g. tracked pages)? For now, we need this to avoid | ||
618 | * invoking kmemcheck for PnP BIOS calls. | ||
619 | */ | ||
620 | if (regs->flags & X86_VM_MASK) | ||
621 | return false; | ||
622 | if (regs->cs != __KERNEL_CS) | ||
623 | return false; | ||
624 | |||
625 | pte = lookup_address(address, &level); | ||
626 | if (!pte) | ||
627 | return false; | ||
628 | if (level != PG_LEVEL_4K) | ||
629 | return false; | ||
630 | if (!pte_hidden(*pte)) | ||
631 | return false; | ||
632 | |||
633 | if (error_code & 2) | ||
634 | kmemcheck_access(regs, address, KMEMCHECK_WRITE); | ||
635 | else | ||
636 | kmemcheck_access(regs, address, KMEMCHECK_READ); | ||
637 | |||
638 | kmemcheck_show(regs); | ||
639 | return true; | ||
640 | } | ||
641 | |||
642 | bool kmemcheck_trap(struct pt_regs *regs) | ||
643 | { | ||
644 | if (!kmemcheck_active(regs)) | ||
645 | return false; | ||
646 | |||
647 | /* We're done. */ | ||
648 | kmemcheck_hide(regs); | ||
649 | return true; | ||
650 | } | ||
diff --git a/arch/x86/mm/kmemcheck/opcode.c b/arch/x86/mm/kmemcheck/opcode.c new file mode 100644 index 000000000000..a4100b6e783a --- /dev/null +++ b/arch/x86/mm/kmemcheck/opcode.c | |||
@@ -0,0 +1,101 @@ | |||
1 | #include <linux/types.h> | ||
2 | |||
3 | #include "opcode.h" | ||
4 | |||
5 | static bool opcode_is_prefix(uint8_t b) | ||
6 | { | ||
7 | return | ||
8 | /* Group 1 */ | ||
9 | b == 0xf0 || b == 0xf2 || b == 0xf3 | ||
10 | /* Group 2 */ | ||
11 | || b == 0x2e || b == 0x36 || b == 0x3e || b == 0x26 | ||
12 | || b == 0x64 || b == 0x65 || b == 0x2e || b == 0x3e | ||
13 | /* Group 3 */ | ||
14 | || b == 0x66 | ||
15 | /* Group 4 */ | ||
16 | || b == 0x67; | ||
17 | } | ||
18 | |||
19 | static bool opcode_is_rex_prefix(uint8_t b) | ||
20 | { | ||
21 | return (b & 0xf0) == 0x40; | ||
22 | } | ||
23 | |||
24 | #define REX_W (1 << 3) | ||
25 | |||
26 | /* | ||
27 | * This is a VERY crude opcode decoder. We only need to find the size of the | ||
28 | * load/store that caused our #PF and this should work for all the opcodes | ||
29 | * that we care about. Moreover, the ones who invented this instruction set | ||
30 | * should be shot. | ||
31 | */ | ||
32 | void kmemcheck_opcode_decode(const uint8_t *op, unsigned int *size) | ||
33 | { | ||
34 | /* Default operand size */ | ||
35 | int operand_size_override = 4; | ||
36 | |||
37 | /* prefixes */ | ||
38 | for (; opcode_is_prefix(*op); ++op) { | ||
39 | if (*op == 0x66) | ||
40 | operand_size_override = 2; | ||
41 | } | ||
42 | |||
43 | #ifdef CONFIG_X86_64 | ||
44 | /* REX prefix */ | ||
45 | if (opcode_is_rex_prefix(*op)) { | ||
46 | uint8_t rex = *op; | ||
47 | |||
48 | ++op; | ||
49 | if (rex & REX_W) { | ||
50 | switch (*op) { | ||
51 | case 0x63: | ||
52 | *size = 4; | ||
53 | return; | ||
54 | case 0x0f: | ||
55 | ++op; | ||
56 | |||
57 | switch (*op) { | ||
58 | case 0xb6: | ||
59 | case 0xbe: | ||
60 | *size = 1; | ||
61 | return; | ||
62 | case 0xb7: | ||
63 | case 0xbf: | ||
64 | *size = 2; | ||
65 | return; | ||
66 | } | ||
67 | |||
68 | break; | ||
69 | } | ||
70 | |||
71 | *size = 8; | ||
72 | return; | ||
73 | } | ||
74 | } | ||
75 | #endif | ||
76 | |||
77 | /* escape opcode */ | ||
78 | if (*op == 0x0f) { | ||
79 | ++op; | ||
80 | |||
81 | /* | ||
82 | * This is move with zero-extend and sign-extend, respectively; | ||
83 | * we don't have to think about 0xb6/0xbe, because this is | ||
84 | * already handled in the conditional below. | ||
85 | */ | ||
86 | if (*op == 0xb7 || *op == 0xbf) | ||
87 | operand_size_override = 2; | ||
88 | } | ||
89 | |||
90 | *size = (*op & 1) ? operand_size_override : 1; | ||
91 | } | ||
92 | |||
93 | const uint8_t *kmemcheck_opcode_get_primary(const uint8_t *op) | ||
94 | { | ||
95 | /* skip prefixes */ | ||
96 | while (opcode_is_prefix(*op)) | ||
97 | ++op; | ||
98 | if (opcode_is_rex_prefix(*op)) | ||
99 | ++op; | ||
100 | return op; | ||
101 | } | ||
diff --git a/arch/x86/mm/kmemcheck/opcode.h b/arch/x86/mm/kmemcheck/opcode.h new file mode 100644 index 000000000000..6956aad66b5b --- /dev/null +++ b/arch/x86/mm/kmemcheck/opcode.h | |||
@@ -0,0 +1,9 @@ | |||
1 | #ifndef ARCH__X86__MM__KMEMCHECK__OPCODE_H | ||
2 | #define ARCH__X86__MM__KMEMCHECK__OPCODE_H | ||
3 | |||
4 | #include <linux/types.h> | ||
5 | |||
6 | void kmemcheck_opcode_decode(const uint8_t *op, unsigned int *size); | ||
7 | const uint8_t *kmemcheck_opcode_get_primary(const uint8_t *op); | ||
8 | |||
9 | #endif | ||
diff --git a/arch/x86/mm/kmemcheck/pte.c b/arch/x86/mm/kmemcheck/pte.c new file mode 100644 index 000000000000..4ead26eeaf96 --- /dev/null +++ b/arch/x86/mm/kmemcheck/pte.c | |||
@@ -0,0 +1,22 @@ | |||
1 | #include <linux/mm.h> | ||
2 | |||
3 | #include <asm/pgtable.h> | ||
4 | |||
5 | #include "pte.h" | ||
6 | |||
7 | pte_t *kmemcheck_pte_lookup(unsigned long address) | ||
8 | { | ||
9 | pte_t *pte; | ||
10 | unsigned int level; | ||
11 | |||
12 | pte = lookup_address(address, &level); | ||
13 | if (!pte) | ||
14 | return NULL; | ||
15 | if (level != PG_LEVEL_4K) | ||
16 | return NULL; | ||
17 | if (!pte_hidden(*pte)) | ||
18 | return NULL; | ||
19 | |||
20 | return pte; | ||
21 | } | ||
22 | |||
diff --git a/arch/x86/mm/kmemcheck/pte.h b/arch/x86/mm/kmemcheck/pte.h new file mode 100644 index 000000000000..9f5966456492 --- /dev/null +++ b/arch/x86/mm/kmemcheck/pte.h | |||
@@ -0,0 +1,10 @@ | |||
1 | #ifndef ARCH__X86__MM__KMEMCHECK__PTE_H | ||
2 | #define ARCH__X86__MM__KMEMCHECK__PTE_H | ||
3 | |||
4 | #include <linux/mm.h> | ||
5 | |||
6 | #include <asm/pgtable.h> | ||
7 | |||
8 | pte_t *kmemcheck_pte_lookup(unsigned long address); | ||
9 | |||
10 | #endif | ||
diff --git a/arch/x86/mm/kmemcheck/shadow.c b/arch/x86/mm/kmemcheck/shadow.c new file mode 100644 index 000000000000..5544d3600877 --- /dev/null +++ b/arch/x86/mm/kmemcheck/shadow.c | |||
@@ -0,0 +1,153 @@ | |||
1 | #include <linux/kmemcheck.h> | ||
2 | #include <linux/module.h> | ||
3 | #include <linux/mm.h> | ||
4 | |||
5 | #include <asm/page.h> | ||
6 | #include <asm/pgtable.h> | ||
7 | |||
8 | #include "pte.h" | ||
9 | #include "shadow.h" | ||
10 | |||
11 | /* | ||
12 | * Return the shadow address for the given address. Returns NULL if the | ||
13 | * address is not tracked. | ||
14 | * | ||
15 | * We need to be extremely careful not to follow any invalid pointers, | ||
16 | * because this function can be called for *any* possible address. | ||
17 | */ | ||
18 | void *kmemcheck_shadow_lookup(unsigned long address) | ||
19 | { | ||
20 | pte_t *pte; | ||
21 | struct page *page; | ||
22 | |||
23 | if (!virt_addr_valid(address)) | ||
24 | return NULL; | ||
25 | |||
26 | pte = kmemcheck_pte_lookup(address); | ||
27 | if (!pte) | ||
28 | return NULL; | ||
29 | |||
30 | page = virt_to_page(address); | ||
31 | if (!page->shadow) | ||
32 | return NULL; | ||
33 | return page->shadow + (address & (PAGE_SIZE - 1)); | ||
34 | } | ||
35 | |||
36 | static void mark_shadow(void *address, unsigned int n, | ||
37 | enum kmemcheck_shadow status) | ||
38 | { | ||
39 | unsigned long addr = (unsigned long) address; | ||
40 | unsigned long last_addr = addr + n - 1; | ||
41 | unsigned long page = addr & PAGE_MASK; | ||
42 | unsigned long last_page = last_addr & PAGE_MASK; | ||
43 | unsigned int first_n; | ||
44 | void *shadow; | ||
45 | |||
46 | /* If the memory range crosses a page boundary, stop there. */ | ||
47 | if (page == last_page) | ||
48 | first_n = n; | ||
49 | else | ||
50 | first_n = page + PAGE_SIZE - addr; | ||
51 | |||
52 | shadow = kmemcheck_shadow_lookup(addr); | ||
53 | if (shadow) | ||
54 | memset(shadow, status, first_n); | ||
55 | |||
56 | addr += first_n; | ||
57 | n -= first_n; | ||
58 | |||
59 | /* Do full-page memset()s. */ | ||
60 | while (n >= PAGE_SIZE) { | ||
61 | shadow = kmemcheck_shadow_lookup(addr); | ||
62 | if (shadow) | ||
63 | memset(shadow, status, PAGE_SIZE); | ||
64 | |||
65 | addr += PAGE_SIZE; | ||
66 | n -= PAGE_SIZE; | ||
67 | } | ||
68 | |||
69 | /* Do the remaining page, if any. */ | ||
70 | if (n > 0) { | ||
71 | shadow = kmemcheck_shadow_lookup(addr); | ||
72 | if (shadow) | ||
73 | memset(shadow, status, n); | ||
74 | } | ||
75 | } | ||
76 | |||
77 | void kmemcheck_mark_unallocated(void *address, unsigned int n) | ||
78 | { | ||
79 | mark_shadow(address, n, KMEMCHECK_SHADOW_UNALLOCATED); | ||
80 | } | ||
81 | |||
82 | void kmemcheck_mark_uninitialized(void *address, unsigned int n) | ||
83 | { | ||
84 | mark_shadow(address, n, KMEMCHECK_SHADOW_UNINITIALIZED); | ||
85 | } | ||
86 | |||
87 | /* | ||
88 | * Fill the shadow memory of the given address such that the memory at that | ||
89 | * address is marked as being initialized. | ||
90 | */ | ||
91 | void kmemcheck_mark_initialized(void *address, unsigned int n) | ||
92 | { | ||
93 | mark_shadow(address, n, KMEMCHECK_SHADOW_INITIALIZED); | ||
94 | } | ||
95 | EXPORT_SYMBOL_GPL(kmemcheck_mark_initialized); | ||
96 | |||
97 | void kmemcheck_mark_freed(void *address, unsigned int n) | ||
98 | { | ||
99 | mark_shadow(address, n, KMEMCHECK_SHADOW_FREED); | ||
100 | } | ||
101 | |||
102 | void kmemcheck_mark_unallocated_pages(struct page *p, unsigned int n) | ||
103 | { | ||
104 | unsigned int i; | ||
105 | |||
106 | for (i = 0; i < n; ++i) | ||
107 | kmemcheck_mark_unallocated(page_address(&p[i]), PAGE_SIZE); | ||
108 | } | ||
109 | |||
110 | void kmemcheck_mark_uninitialized_pages(struct page *p, unsigned int n) | ||
111 | { | ||
112 | unsigned int i; | ||
113 | |||
114 | for (i = 0; i < n; ++i) | ||
115 | kmemcheck_mark_uninitialized(page_address(&p[i]), PAGE_SIZE); | ||
116 | } | ||
117 | |||
118 | enum kmemcheck_shadow kmemcheck_shadow_test(void *shadow, unsigned int size) | ||
119 | { | ||
120 | uint8_t *x; | ||
121 | unsigned int i; | ||
122 | |||
123 | x = shadow; | ||
124 | |||
125 | #ifdef CONFIG_KMEMCHECK_PARTIAL_OK | ||
126 | /* | ||
127 | * Make sure _some_ bytes are initialized. Gcc frequently generates | ||
128 | * code to access neighboring bytes. | ||
129 | */ | ||
130 | for (i = 0; i < size; ++i) { | ||
131 | if (x[i] == KMEMCHECK_SHADOW_INITIALIZED) | ||
132 | return x[i]; | ||
133 | } | ||
134 | #else | ||
135 | /* All bytes must be initialized. */ | ||
136 | for (i = 0; i < size; ++i) { | ||
137 | if (x[i] != KMEMCHECK_SHADOW_INITIALIZED) | ||
138 | return x[i]; | ||
139 | } | ||
140 | #endif | ||
141 | |||
142 | return x[0]; | ||
143 | } | ||
144 | |||
145 | void kmemcheck_shadow_set(void *shadow, unsigned int size) | ||
146 | { | ||
147 | uint8_t *x; | ||
148 | unsigned int i; | ||
149 | |||
150 | x = shadow; | ||
151 | for (i = 0; i < size; ++i) | ||
152 | x[i] = KMEMCHECK_SHADOW_INITIALIZED; | ||
153 | } | ||
diff --git a/arch/x86/mm/kmemcheck/shadow.h b/arch/x86/mm/kmemcheck/shadow.h new file mode 100644 index 000000000000..af46d9ab9d86 --- /dev/null +++ b/arch/x86/mm/kmemcheck/shadow.h | |||
@@ -0,0 +1,16 @@ | |||
1 | #ifndef ARCH__X86__MM__KMEMCHECK__SHADOW_H | ||
2 | #define ARCH__X86__MM__KMEMCHECK__SHADOW_H | ||
3 | |||
4 | enum kmemcheck_shadow { | ||
5 | KMEMCHECK_SHADOW_UNALLOCATED, | ||
6 | KMEMCHECK_SHADOW_UNINITIALIZED, | ||
7 | KMEMCHECK_SHADOW_INITIALIZED, | ||
8 | KMEMCHECK_SHADOW_FREED, | ||
9 | }; | ||
10 | |||
11 | void *kmemcheck_shadow_lookup(unsigned long address); | ||
12 | |||
13 | enum kmemcheck_shadow kmemcheck_shadow_test(void *shadow, unsigned int size); | ||
14 | void kmemcheck_shadow_set(void *shadow, unsigned int size); | ||
15 | |||
16 | #endif | ||