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Leonardo Braspalmer-dabbelt
Leonardo Bras
authored and
palmer-dabbelt
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riscv/cmpxchg: Deduplicate cmpxchg() asm and macros
In this header every cmpxchg define (_relaxed, _acquire, _release, vanilla) contain it's own asm file, both for 4-byte variables an 8-byte variables, on a total of 8 versions of mostly the same asm. This is usually bad, as it means any change may be done in up to 8 different places. Unify those versions by creating a new define with enough parameters to generate any version of the previous 8. Then unify the result under a more general define, and simplify arch_cmpxchg* generation (This did not cause any change in generated asm) Signed-off-by: Leonardo Bras <leobras@redhat.com> Reviewed-by: Guo Ren <guoren@kernel.org> Reviewed-by: Andrea Parri <parri.andrea@gmail.com> Tested-by: Guo Ren <guoren@kernel.org> Link: https://lore.kernel.org/r/20240103163203.72768-4-leobras@redhat.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Lines changed: 33 additions & 162 deletions

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‎arch/riscv/include/asm/cmpxchg.h‎

Lines changed: 33 additions & 162 deletions
Original file line numberDiff line numberDiff line change
@@ -71,190 +71,61 @@
7171
* store NEW in MEM. Return the initial value in MEM. Success is
7272
* indicated by comparing RETURN with OLD.
7373
*/
74-
#define __cmpxchg_relaxed(ptr, old, new, size) \
75-
({ \
76-
__typeof__(ptr) __ptr = (ptr); \
77-
__typeof__(*(ptr)) __old = (old); \
78-
__typeof__(*(ptr)) __new = (new); \
79-
__typeof__(*(ptr)) __ret; \
80-
register unsigned int __rc; \
81-
switch (size) { \
82-
case 4: \
83-
__asm__ __volatile__ ( \
84-
"0: lr.w %0, %2\n" \
85-
" bne %0, %z3, 1f\n" \
86-
" sc.w %1, %z4, %2\n" \
87-
" bnez %1, 0b\n" \
88-
"1:\n" \
89-
: "=&r" (__ret), "=&r" (__rc), "+A" (*__ptr) \
90-
: "rJ" ((long)__old), "rJ" (__new) \
91-
: "memory"); \
92-
break; \
93-
case 8: \
94-
__asm__ __volatile__ ( \
95-
"0: lr.d %0, %2\n" \
96-
" bne %0, %z3, 1f\n" \
97-
" sc.d %1, %z4, %2\n" \
98-
" bnez %1, 0b\n" \
99-
"1:\n" \
100-
: "=&r" (__ret), "=&r" (__rc), "+A" (*__ptr) \
101-
: "rJ" (__old), "rJ" (__new) \
102-
: "memory"); \
103-
break; \
104-
default: \
105-
BUILD_BUG(); \
106-
} \
107-
__ret; \
108-
})
10974

110-
#define arch_cmpxchg_relaxed(ptr, o, n) \
111-
({ \
112-
__typeof__(*(ptr)) _o_ = (o); \
113-
__typeof__(*(ptr)) _n_ = (n); \
114-
(__typeof__(*(ptr))) __cmpxchg_relaxed((ptr), \
115-
_o_, _n_, sizeof(*(ptr))); \
116-
})
11775

118-
#define __cmpxchg_acquire(ptr, old, new, size) \
76+
#define __arch_cmpxchg(lr_sfx, sc_sfx, prepend, append, r, p, co, o, n) \
11977
({ \
120-
__typeof__(ptr) __ptr = (ptr); \
121-
__typeof__(*(ptr)) __old = (old); \
122-
__typeof__(*(ptr)) __new = (new); \
123-
__typeof__(*(ptr)) __ret; \
12478
register unsigned int __rc; \
125-
switch (size) { \
126-
case 4: \
127-
__asm__ __volatile__ ( \
128-
"0: lr.w %0, %2\n" \
129-
" bne %0, %z3, 1f\n" \
130-
" sc.w %1, %z4, %2\n" \
131-
" bnez %1, 0b\n" \
132-
RISCV_ACQUIRE_BARRIER \
133-
"1:\n" \
134-
: "=&r" (__ret), "=&r" (__rc), "+A" (*__ptr) \
135-
: "rJ" ((long)__old), "rJ" (__new) \
136-
: "memory"); \
137-
break; \
138-
case 8: \
139-
__asm__ __volatile__ ( \
140-
"0: lr.d %0, %2\n" \
141-
" bne %0, %z3, 1f\n" \
142-
" sc.d %1, %z4, %2\n" \
143-
" bnez %1, 0b\n" \
144-
RISCV_ACQUIRE_BARRIER \
145-
"1:\n" \
146-
: "=&r" (__ret), "=&r" (__rc), "+A" (*__ptr) \
147-
: "rJ" (__old), "rJ" (__new) \
148-
: "memory"); \
149-
break; \
150-
default: \
151-
BUILD_BUG(); \
152-
} \
153-
__ret; \
154-
})
155-
156-
#define arch_cmpxchg_acquire(ptr, o, n) \
157-
({ \
158-
__typeof__(*(ptr)) _o_ = (o); \
159-
__typeof__(*(ptr)) _n_ = (n); \
160-
(__typeof__(*(ptr))) __cmpxchg_acquire((ptr), \
161-
_o_, _n_, sizeof(*(ptr))); \
79+
\
80+
__asm__ __volatile__ ( \
81+
prepend \
82+
"0: lr" lr_sfx " %0, %2\n" \
83+
" bne %0, %z3, 1f\n" \
84+
" sc" sc_sfx " %1, %z4, %2\n" \
85+
" bnez %1, 0b\n" \
86+
append \
87+
"1:\n" \
88+
: "=&r" (r), "=&r" (__rc), "+A" (*(p)) \
89+
: "rJ" (co o), "rJ" (n) \
90+
: "memory"); \
16291
})
16392

164-
#define __cmpxchg_release(ptr, old, new, size) \
93+
#define _arch_cmpxchg(ptr, old, new, sc_sfx, prepend, append) \
16594
({ \
16695
__typeof__(ptr) __ptr = (ptr); \
167-
__typeof__(*(ptr)) __old = (old); \
168-
__typeof__(*(ptr)) __new = (new); \
169-
__typeof__(*(ptr)) __ret; \
170-
register unsigned int __rc; \
171-
switch (size) { \
96+
__typeof__(*(__ptr)) __old = (old); \
97+
__typeof__(*(__ptr)) __new = (new); \
98+
__typeof__(*(__ptr)) __ret; \
99+
\
100+
switch (sizeof(*__ptr)) { \
172101
case 4: \
173-
__asm__ __volatile__ ( \
174-
RISCV_RELEASE_BARRIER \
175-
"0: lr.w %0, %2\n" \
176-
" bne %0, %z3, 1f\n" \
177-
" sc.w %1, %z4, %2\n" \
178-
" bnez %1, 0b\n" \
179-
"1:\n" \
180-
: "=&r" (__ret), "=&r" (__rc), "+A" (*__ptr) \
181-
: "rJ" ((long)__old), "rJ" (__new) \
182-
: "memory"); \
102+
__arch_cmpxchg(".w", ".w" sc_sfx, prepend, append, \
103+
__ret, __ptr, (long), __old, __new); \
183104
break; \
184105
case 8: \
185-
__asm__ __volatile__ ( \
186-
RISCV_RELEASE_BARRIER \
187-
"0: lr.d %0, %2\n" \
188-
" bne %0, %z3, 1f\n" \
189-
" sc.d %1, %z4, %2\n" \
190-
" bnez %1, 0b\n" \
191-
"1:\n" \
192-
: "=&r" (__ret), "=&r" (__rc), "+A" (*__ptr) \
193-
: "rJ" (__old), "rJ" (__new) \
194-
: "memory"); \
106+
__arch_cmpxchg(".d", ".d" sc_sfx, prepend, append, \
107+
__ret, __ptr, /**/, __old, __new); \
195108
break; \
196109
default: \
197110
BUILD_BUG(); \
198111
} \
199-
__ret; \
112+
(__typeof__(*(__ptr)))__ret; \
200113
})
201114

202-
#define arch_cmpxchg_release(ptr, o, n) \
203-
({ \
204-
__typeof__(*(ptr)) _o_ = (o); \
205-
__typeof__(*(ptr)) _n_ = (n); \
206-
(__typeof__(*(ptr))) __cmpxchg_release((ptr), \
207-
_o_, _n_, sizeof(*(ptr))); \
208-
})
115+
#define arch_cmpxchg_relaxed(ptr, o, n) \
116+
_arch_cmpxchg((ptr), (o), (n), "", "", "")
209117

210-
#define __cmpxchg(ptr, old, new, size) \
211-
({ \
212-
__typeof__(ptr) __ptr = (ptr); \
213-
__typeof__(*(ptr)) __old = (old); \
214-
__typeof__(*(ptr)) __new = (new); \
215-
__typeof__(*(ptr)) __ret; \
216-
register unsigned int __rc; \
217-
switch (size) { \
218-
case 4: \
219-
__asm__ __volatile__ ( \
220-
"0: lr.w %0, %2\n" \
221-
" bne %0, %z3, 1f\n" \
222-
" sc.w.rl %1, %z4, %2\n" \
223-
" bnez %1, 0b\n" \
224-
" fence rw, rw\n" \
225-
"1:\n" \
226-
: "=&r" (__ret), "=&r" (__rc), "+A" (*__ptr) \
227-
: "rJ" ((long)__old), "rJ" (__new) \
228-
: "memory"); \
229-
break; \
230-
case 8: \
231-
__asm__ __volatile__ ( \
232-
"0: lr.d %0, %2\n" \
233-
" bne %0, %z3, 1f\n" \
234-
" sc.d.rl %1, %z4, %2\n" \
235-
" bnez %1, 0b\n" \
236-
" fence rw, rw\n" \
237-
"1:\n" \
238-
: "=&r" (__ret), "=&r" (__rc), "+A" (*__ptr) \
239-
: "rJ" (__old), "rJ" (__new) \
240-
: "memory"); \
241-
break; \
242-
default: \
243-
BUILD_BUG(); \
244-
} \
245-
__ret; \
246-
})
118+
#define arch_cmpxchg_acquire(ptr, o, n) \
119+
_arch_cmpxchg((ptr), (o), (n), "", "", RISCV_ACQUIRE_BARRIER)
120+
121+
#define arch_cmpxchg_release(ptr, o, n) \
122+
_arch_cmpxchg((ptr), (o), (n), "", RISCV_RELEASE_BARRIER, "")
247123

248124
#define arch_cmpxchg(ptr, o, n) \
249-
({ \
250-
__typeof__(*(ptr)) _o_ = (o); \
251-
__typeof__(*(ptr)) _n_ = (n); \
252-
(__typeof__(*(ptr))) __cmpxchg((ptr), \
253-
_o_, _n_, sizeof(*(ptr))); \
254-
})
125+
_arch_cmpxchg((ptr), (o), (n), ".rl", "", " fence rw, rw\n")
255126

256127
#define arch_cmpxchg_local(ptr, o, n) \
257-
(__cmpxchg_relaxed((ptr), (o), (n), sizeof(*(ptr))))
128+
arch_cmpxchg_relaxed((ptr), (o), (n))
258129

259130
#define arch_cmpxchg64(ptr, o, n) \
260131
({ \

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