aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorPeter Zijlstra <a.p.zijlstra@chello.nl>2009-10-09 04:12:46 -0400
committerIngo Molnar <mingo@elte.hu>2009-10-09 09:57:00 -0400
commitf3834b9ef68067199486740b31f691afb14dbdf5 (patch)
tree825825528f9501095da3101da7ad2f0e2a6351a4
parent63312b6a6faae3f2e5577f2b001e3b504f10a2aa (diff)
x86: Generate cmpxchg build failures
Rework the x86 cmpxchg() implementation to generate build failures when used on improper types. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> LKML-Reference: <1254771187.21044.22.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat
-rw-r--r--arch/x86/include/asm/cmpxchg_32.h218
-rw-r--r--arch/x86/include/asm/cmpxchg_64.h234
2 files changed, 177 insertions, 275 deletions
diff --git a/arch/x86/include/asm/cmpxchg_32.h b/arch/x86/include/asm/cmpxchg_32.h
index 82ceb788a981..5371174cf5d0 100644
--- a/arch/x86/include/asm/cmpxchg_32.h
+++ b/arch/x86/include/asm/cmpxchg_32.h
@@ -8,14 +8,50 @@
8 * you need to test for the feature in boot_cpu_data. 8 * you need to test for the feature in boot_cpu_data.
9 */ 9 */
10 10
11#define xchg(ptr, v) \ 11extern void __xchg_wrong_size(void);
12 ((__typeof__(*(ptr)))__xchg((unsigned long)(v), (ptr), sizeof(*(ptr)))) 12
13/*
14 * Note: no "lock" prefix even on SMP: xchg always implies lock anyway
15 * Note 2: xchg has side effect, so that attribute volatile is necessary,
16 * but generally the primitive is invalid, *ptr is output argument. --ANK
17 */
13 18
14struct __xchg_dummy { 19struct __xchg_dummy {
15 unsigned long a[100]; 20 unsigned long a[100];
16}; 21};
17#define __xg(x) ((struct __xchg_dummy *)(x)) 22#define __xg(x) ((struct __xchg_dummy *)(x))
18 23
24#define __xchg(x, ptr, size) \
25({ \
26 __typeof(*(ptr)) __x = (x); \
27 switch (size) { \
28 case 1: \
29 asm volatile("xchgb %b0,%1" \
30 : "=q" (__x) \
31 : "m" (*__xg(ptr)), "0" (__x) \
32 : "memory"); \
33 break; \
34 case 2: \
35 asm volatile("xchgw %w0,%1" \
36 : "=r" (__x) \
37 : "m" (*__xg(ptr)), "0" (__x) \
38 : "memory"); \
39 break; \
40 case 4: \
41 asm volatile("xchgl %0,%1" \
42 : "=r" (__x) \
43 : "m" (*__xg(ptr)), "0" (__x) \
44 : "memory"); \
45 break; \
46 default: \
47 __xchg_wrong_size(); \
48 } \
49 __x; \
50})
51
52#define xchg(ptr, v) \
53 __xchg((v), (ptr), sizeof(*ptr))
54
19/* 55/*
20 * The semantics of XCHGCMP8B are a bit strange, this is why 56 * The semantics of XCHGCMP8B are a bit strange, this is why
21 * there is a loop and the loading of %%eax and %%edx has to 57 * there is a loop and the loading of %%eax and %%edx has to
@@ -71,57 +107,63 @@ static inline void __set_64bit_var(unsigned long long *ptr,
71 (unsigned int)((value) >> 32)) \ 107 (unsigned int)((value) >> 32)) \
72 : __set_64bit(ptr, ll_low((value)), ll_high((value)))) 108 : __set_64bit(ptr, ll_low((value)), ll_high((value))))
73 109
74/* 110extern void __cmpxchg_wrong_size(void);
75 * Note: no "lock" prefix even on SMP: xchg always implies lock anyway
76 * Note 2: xchg has side effect, so that attribute volatile is necessary,
77 * but generally the primitive is invalid, *ptr is output argument. --ANK
78 */
79static inline unsigned long __xchg(unsigned long x, volatile void *ptr,
80 int size)
81{
82 switch (size) {
83 case 1:
84 asm volatile("xchgb %b0,%1"
85 : "=q" (x)
86 : "m" (*__xg(ptr)), "0" (x)
87 : "memory");
88 break;
89 case 2:
90 asm volatile("xchgw %w0,%1"
91 : "=r" (x)
92 : "m" (*__xg(ptr)), "0" (x)
93 : "memory");
94 break;
95 case 4:
96 asm volatile("xchgl %0,%1"
97 : "=r" (x)
98 : "m" (*__xg(ptr)), "0" (x)
99 : "memory");
100 break;
101 }
102 return x;
103}
104 111
105/* 112/*
106 * Atomic compare and exchange. Compare OLD with MEM, if identical, 113 * Atomic compare and exchange. Compare OLD with MEM, if identical,
107 * store NEW in MEM. Return the initial value in MEM. Success is 114 * store NEW in MEM. Return the initial value in MEM. Success is
108 * indicated by comparing RETURN with OLD. 115 * indicated by comparing RETURN with OLD.
109 */ 116 */
117#define __raw_cmpxchg(ptr, old, new, size, lock) \
118({ \
119 __typeof__(*(ptr)) __ret; \
120 __typeof__(*(ptr)) __old = (old); \
121 __typeof__(*(ptr)) __new = (new); \
122 switch (size) { \
123 case 1: \
124 asm volatile(lock "cmpxchgb %b1,%2" \
125 : "=a"(__ret) \
126 : "q"(__new), "m"(*__xg(ptr)), "0"(__old) \
127 : "memory"); \
128 break; \
129 case 2: \
130 asm volatile(lock "cmpxchgw %w1,%2" \
131 : "=a"(__ret) \
132 : "r"(__new), "m"(*__xg(ptr)), "0"(__old) \
133 : "memory"); \
134 break; \
135 case 4: \
136 asm volatile(lock "cmpxchgl %1,%2" \
137 : "=a"(__ret) \
138 : "r"(__new), "m"(*__xg(ptr)), "0"(__old) \
139 : "memory"); \
140 break; \
141 default: \
142 __cmpxchg_wrong_size(); \
143 } \
144 __ret; \
145})
146
147#define __cmpxchg(ptr, old, new, size) \
148 __raw_cmpxchg((ptr), (old), (new), (size), LOCK_PREFIX)
149
150#define __sync_cmpxchg(ptr, old, new, size) \
151 __raw_cmpxchg((ptr), (old), (new), (size), "lock; ")
152
153#define __cmpxchg_local(ptr, old, new, size) \
154 __raw_cmpxchg((ptr), (old), (new), (size), "")
110 155
111#ifdef CONFIG_X86_CMPXCHG 156#ifdef CONFIG_X86_CMPXCHG
112#define __HAVE_ARCH_CMPXCHG 1 157#define __HAVE_ARCH_CMPXCHG 1
113#define cmpxchg(ptr, o, n) \ 158
114 ((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(o), \ 159#define cmpxchg(ptr, old, new) \
115 (unsigned long)(n), \ 160 __cmpxchg((ptr), (old), (new), sizeof(*ptr))
116 sizeof(*(ptr)))) 161
117#define sync_cmpxchg(ptr, o, n) \ 162#define sync_cmpxchg(ptr, old, new) \
118 ((__typeof__(*(ptr)))__sync_cmpxchg((ptr), (unsigned long)(o), \ 163 __sync_cmpxchg((ptr), (old), (new), sizeof(*ptr))
119 (unsigned long)(n), \ 164
120 sizeof(*(ptr)))) 165#define cmpxchg_local(ptr, old, new) \
121#define cmpxchg_local(ptr, o, n) \ 166 __cmpxchg_local((ptr), (old), (new), sizeof(*ptr))
122 ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
123 (unsigned long)(n), \
124 sizeof(*(ptr))))
125#endif 167#endif
126 168
127#ifdef CONFIG_X86_CMPXCHG64 169#ifdef CONFIG_X86_CMPXCHG64
@@ -133,94 +175,6 @@ static inline unsigned long __xchg(unsigned long x, volatile void *ptr,
133 (unsigned long long)(n))) 175 (unsigned long long)(n)))
134#endif 176#endif
135 177
136static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
137 unsigned long new, int size)
138{
139 unsigned long prev;
140 switch (size) {
141 case 1:
142 asm volatile(LOCK_PREFIX "cmpxchgb %b1,%2"
143 : "=a"(prev)
144 : "q"(new), "m"(*__xg(ptr)), "0"(old)
145 : "memory");
146 return prev;
147 case 2:
148 asm volatile(LOCK_PREFIX "cmpxchgw %w1,%2"
149 : "=a"(prev)
150 : "r"(new), "m"(*__xg(ptr)), "0"(old)
151 : "memory");
152 return prev;
153 case 4:
154 asm volatile(LOCK_PREFIX "cmpxchgl %1,%2"
155 : "=a"(prev)
156 : "r"(new), "m"(*__xg(ptr)), "0"(old)
157 : "memory");
158 return prev;
159 }
160 return old;
161}
162
163/*
164 * Always use locked operations when touching memory shared with a
165 * hypervisor, since the system may be SMP even if the guest kernel
166 * isn't.
167 */
168static inline unsigned long __sync_cmpxchg(volatile void *ptr,
169 unsigned long old,
170 unsigned long new, int size)
171{
172 unsigned long prev;
173 switch (size) {
174 case 1:
175 asm volatile("lock; cmpxchgb %b1,%2"
176 : "=a"(prev)
177 : "q"(new), "m"(*__xg(ptr)), "0"(old)
178 : "memory");
179 return prev;
180 case 2:
181 asm volatile("lock; cmpxchgw %w1,%2"
182 : "=a"(prev)
183 : "r"(new), "m"(*__xg(ptr)), "0"(old)
184 : "memory");
185 return prev;
186 case 4:
187 asm volatile("lock; cmpxchgl %1,%2"
188 : "=a"(prev)
189 : "r"(new), "m"(*__xg(ptr)), "0"(old)
190 : "memory");
191 return prev;
192 }
193 return old;
194}
195
196static inline unsigned long __cmpxchg_local(volatile void *ptr,
197 unsigned long old,
198 unsigned long new, int size)
199{
200 unsigned long prev;
201 switch (size) {
202 case 1:
203 asm volatile("cmpxchgb %b1,%2"
204 : "=a"(prev)
205 : "q"(new), "m"(*__xg(ptr)), "0"(old)
206 : "memory");
207 return prev;
208 case 2:
209 asm volatile("cmpxchgw %w1,%2"
210 : "=a"(prev)
211 : "r"(new), "m"(*__xg(ptr)), "0"(old)
212 : "memory");
213 return prev;
214 case 4:
215 asm volatile("cmpxchgl %1,%2"
216 : "=a"(prev)
217 : "r"(new), "m"(*__xg(ptr)), "0"(old)
218 : "memory");
219 return prev;
220 }
221 return old;
222}
223
224static inline unsigned long long __cmpxchg64(volatile void *ptr, 178static inline unsigned long long __cmpxchg64(volatile void *ptr,
225 unsigned long long old, 179 unsigned long long old,
226 unsigned long long new) 180 unsigned long long new)
diff --git a/arch/x86/include/asm/cmpxchg_64.h b/arch/x86/include/asm/cmpxchg_64.h
index 52de72e0de8c..485ae415faec 100644
--- a/arch/x86/include/asm/cmpxchg_64.h
+++ b/arch/x86/include/asm/cmpxchg_64.h
@@ -3,9 +3,6 @@
3 3
4#include <asm/alternative.h> /* Provides LOCK_PREFIX */ 4#include <asm/alternative.h> /* Provides LOCK_PREFIX */
5 5
6#define xchg(ptr, v) ((__typeof__(*(ptr)))__xchg((unsigned long)(v), \
7 (ptr), sizeof(*(ptr))))
8
9#define __xg(x) ((volatile long *)(x)) 6#define __xg(x) ((volatile long *)(x))
10 7
11static inline void set_64bit(volatile unsigned long *ptr, unsigned long val) 8static inline void set_64bit(volatile unsigned long *ptr, unsigned long val)
@@ -15,167 +12,118 @@ static inline void set_64bit(volatile unsigned long *ptr, unsigned long val)
15 12
16#define _set_64bit set_64bit 13#define _set_64bit set_64bit
17 14
15extern void __xchg_wrong_size(void);
16extern void __cmpxchg_wrong_size(void);
17
18/* 18/*
19 * Note: no "lock" prefix even on SMP: xchg always implies lock anyway 19 * Note: no "lock" prefix even on SMP: xchg always implies lock anyway
20 * Note 2: xchg has side effect, so that attribute volatile is necessary, 20 * Note 2: xchg has side effect, so that attribute volatile is necessary,
21 * but generally the primitive is invalid, *ptr is output argument. --ANK 21 * but generally the primitive is invalid, *ptr is output argument. --ANK
22 */ 22 */
23static inline unsigned long __xchg(unsigned long x, volatile void *ptr, 23#define __xchg(x, ptr, size) \
24 int size) 24({ \
25{ 25 __typeof(*(ptr)) __x = (x); \
26 switch (size) { 26 switch (size) { \
27 case 1: 27 case 1: \
28 asm volatile("xchgb %b0,%1" 28 asm volatile("xchgb %b0,%1" \
29 : "=q" (x) 29 : "=q" (__x) \
30 : "m" (*__xg(ptr)), "0" (x) 30 : "m" (*__xg(ptr)), "0" (__x) \
31 : "memory"); 31 : "memory"); \
32 break; 32 break; \
33 case 2: 33 case 2: \
34 asm volatile("xchgw %w0,%1" 34 asm volatile("xchgw %w0,%1" \
35 : "=r" (x) 35 : "=r" (__x) \
36 : "m" (*__xg(ptr)), "0" (x) 36 : "m" (*__xg(ptr)), "0" (__x) \
37 : "memory"); 37 : "memory"); \
38 break; 38 break; \
39 case 4: 39 case 4: \
40 asm volatile("xchgl %k0,%1" 40 asm volatile("xchgl %k0,%1" \
41 : "=r" (x) 41 : "=r" (__x) \
42 : "m" (*__xg(ptr)), "0" (x) 42 : "m" (*__xg(ptr)), "0" (__x) \
43 : "memory"); 43 : "memory"); \
44 break; 44 break; \
45 case 8: 45 case 8: \
46 asm volatile("xchgq %0,%1" 46 asm volatile("xchgq %0,%1" \
47 : "=r" (x) 47 : "=r" (__x) \
48 : "m" (*__xg(ptr)), "0" (x) 48 : "m" (*__xg(ptr)), "0" (__x) \
49 : "memory"); 49 : "memory"); \
50 break; 50 break; \
51 } 51 default: \
52 return x; 52 __xchg_wrong_size(); \
53} 53 } \
54 __x; \
55})
56
57#define xchg(ptr, v) \
58 __xchg((v), (ptr), sizeof(*ptr))
59
60#define __HAVE_ARCH_CMPXCHG 1
54 61
55/* 62/*
56 * Atomic compare and exchange. Compare OLD with MEM, if identical, 63 * Atomic compare and exchange. Compare OLD with MEM, if identical,
57 * store NEW in MEM. Return the initial value in MEM. Success is 64 * store NEW in MEM. Return the initial value in MEM. Success is
58 * indicated by comparing RETURN with OLD. 65 * indicated by comparing RETURN with OLD.
59 */ 66 */
67#define __raw_cmpxchg(ptr, old, new, size, lock) \
68({ \
69 __typeof__(*(ptr)) __ret; \
70 __typeof__(*(ptr)) __old = (old); \
71 __typeof__(*(ptr)) __new = (new); \
72 switch (size) { \
73 case 1: \
74 asm volatile(lock "cmpxchgb %b1,%2" \
75 : "=a"(__ret) \
76 : "q"(__new), "m"(*__xg(ptr)), "0"(__old) \
77 : "memory"); \
78 break; \
79 case 2: \
80 asm volatile(lock "cmpxchgw %w1,%2" \
81 : "=a"(__ret) \
82 : "r"(__new), "m"(*__xg(ptr)), "0"(__old) \
83 : "memory"); \
84 break; \
85 case 4: \
86 asm volatile(lock "cmpxchgl %k1,%2" \
87 : "=a"(__ret) \
88 : "r"(__new), "m"(*__xg(ptr)), "0"(__old) \
89 : "memory"); \
90 break; \
91 case 8: \
92 asm volatile(lock "cmpxchgq %1,%2" \
93 : "=a"(__ret) \
94 : "r"(__new), "m"(*__xg(ptr)), "0"(__old) \
95 : "memory"); \
96 break; \
97 default: \
98 __cmpxchg_wrong_size(); \
99 } \
100 __ret; \
101})
60 102
61#define __HAVE_ARCH_CMPXCHG 1 103#define __cmpxchg(ptr, old, new, size) \
104 __raw_cmpxchg((ptr), (old), (new), (size), LOCK_PREFIX)
62 105
63static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old, 106#define __sync_cmpxchg(ptr, old, new, size) \
64 unsigned long new, int size) 107 __raw_cmpxchg((ptr), (old), (new), (size), "lock; ")
65{
66 unsigned long prev;
67 switch (size) {
68 case 1:
69 asm volatile(LOCK_PREFIX "cmpxchgb %b1,%2"
70 : "=a"(prev)
71 : "q"(new), "m"(*__xg(ptr)), "0"(old)
72 : "memory");
73 return prev;
74 case 2:
75 asm volatile(LOCK_PREFIX "cmpxchgw %w1,%2"
76 : "=a"(prev)
77 : "r"(new), "m"(*__xg(ptr)), "0"(old)
78 : "memory");
79 return prev;
80 case 4:
81 asm volatile(LOCK_PREFIX "cmpxchgl %k1,%2"
82 : "=a"(prev)
83 : "r"(new), "m"(*__xg(ptr)), "0"(old)
84 : "memory");
85 return prev;
86 case 8:
87 asm volatile(LOCK_PREFIX "cmpxchgq %1,%2"
88 : "=a"(prev)
89 : "r"(new), "m"(*__xg(ptr)), "0"(old)
90 : "memory");
91 return prev;
92 }
93 return old;
94}
95 108
96/* 109#define __cmpxchg_local(ptr, old, new, size) \
97 * Always use locked operations when touching memory shared with a 110 __raw_cmpxchg((ptr), (old), (new), (size), "")
98 * hypervisor, since the system may be SMP even if the guest kernel
99 * isn't.
100 */
101static inline unsigned long __sync_cmpxchg(volatile void *ptr,
102 unsigned long old,
103 unsigned long new, int size)
104{
105 unsigned long prev;
106 switch (size) {
107 case 1:
108 asm volatile("lock; cmpxchgb %b1,%2"
109 : "=a"(prev)
110 : "q"(new), "m"(*__xg(ptr)), "0"(old)
111 : "memory");
112 return prev;
113 case 2:
114 asm volatile("lock; cmpxchgw %w1,%2"
115 : "=a"(prev)
116 : "r"(new), "m"(*__xg(ptr)), "0"(old)
117 : "memory");
118 return prev;
119 case 4:
120 asm volatile("lock; cmpxchgl %1,%2"
121 : "=a"(prev)
122 : "r"(new), "m"(*__xg(ptr)), "0"(old)
123 : "memory");
124 return prev;
125 }
126 return old;
127}
128 111
129static inline unsigned long __cmpxchg_local(volatile void *ptr, 112#define cmpxchg(ptr, old, new) \
130 unsigned long old, 113 __cmpxchg((ptr), (old), (new), sizeof(*ptr))
131 unsigned long new, int size) 114
132{ 115#define sync_cmpxchg(ptr, old, new) \
133 unsigned long prev; 116 __sync_cmpxchg((ptr), (old), (new), sizeof(*ptr))
134 switch (size) { 117
135 case 1: 118#define cmpxchg_local(ptr, old, new) \
136 asm volatile("cmpxchgb %b1,%2" 119 __cmpxchg_local((ptr), (old), (new), sizeof(*ptr))
137 : "=a"(prev)
138 : "q"(new), "m"(*__xg(ptr)), "0"(old)
139 : "memory");
140 return prev;
141 case 2:
142 asm volatile("cmpxchgw %w1,%2"
143 : "=a"(prev)
144 : "r"(new), "m"(*__xg(ptr)), "0"(old)
145 : "memory");
146 return prev;
147 case 4:
148 asm volatile("cmpxchgl %k1,%2"
149 : "=a"(prev)
150 : "r"(new), "m"(*__xg(ptr)), "0"(old)
151 : "memory");
152 return prev;
153 case 8:
154 asm volatile("cmpxchgq %1,%2"
155 : "=a"(prev)
156 : "r"(new), "m"(*__xg(ptr)), "0"(old)
157 : "memory");
158 return prev;
159 }
160 return old;
161}
162 120
163#define cmpxchg(ptr, o, n) \
164 ((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(o), \
165 (unsigned long)(n), sizeof(*(ptr))))
166#define cmpxchg64(ptr, o, n) \ 121#define cmpxchg64(ptr, o, n) \
167({ \ 122({ \
168 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \ 123 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
169 cmpxchg((ptr), (o), (n)); \ 124 cmpxchg((ptr), (o), (n)); \
170}) 125})
171#define cmpxchg_local(ptr, o, n) \ 126
172 ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
173 (unsigned long)(n), \
174 sizeof(*(ptr))))
175#define sync_cmpxchg(ptr, o, n) \
176 ((__typeof__(*(ptr)))__sync_cmpxchg((ptr), (unsigned long)(o), \
177 (unsigned long)(n), \
178 sizeof(*(ptr))))
179#define cmpxchg64_local(ptr, o, n) \ 127#define cmpxchg64_local(ptr, o, n) \
180({ \ 128({ \
181 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \ 129 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
generated by cgit v1.2.2 (git 2.25.0) at 2025-12-25 07:19:58 -0500