1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3 * PowerPC atomic bit operations.
4 *
5 * Merged version by David Gibson <david@gibson.dropbear.id.au>.
6 * Based on ppc64 versions by: Dave Engebretsen, Todd Inglett, Don
7 * Reed, Pat McCarthy, Peter Bergner, Anton Blanchard. They
8 * originally took it from the ppc32 code.
9 *
10 * Within a word, bits are numbered LSB first. Lot's of places make
11 * this assumption by directly testing bits with (val & (1<<nr)).
12 * This can cause confusion for large (> 1 word) bitmaps on a
13 * big-endian system because, unlike little endian, the number of each
14 * bit depends on the word size.
15 *
16 * The bitop functions are defined to work on unsigned longs, so for a
17 * ppc64 system the bits end up numbered:
18 * |63..............0|127............64|191...........128|255...........192|
19 * and on ppc32:
20 * |31.....0|63....32|95....64|127...96|159..128|191..160|223..192|255..224|
21 *
22 * There are a few little-endian macros used mostly for filesystem
23 * bitmaps, these work on similar bit arrays layouts, but
24 * byte-oriented:
25 * |7...0|15...8|23...16|31...24|39...32|47...40|55...48|63...56|
26 *
27 * The main difference is that bit 3-5 (64b) or 3-4 (32b) in the bit
28 * number field needs to be reversed compared to the big-endian bit
29 * fields. This can be achieved by XOR with 0x38 (64b) or 0x18 (32b).
30 */
31
32 #ifndef _ASM_POWERPC_BITOPS_H
33 #define _ASM_POWERPC_BITOPS_H
34
35 #ifdef __KERNEL__
36
37 #ifndef _LINUX_BITOPS_H
38 #error only <linux/bitops.h> can be included directly
39 #endif
40
41 #include <linux/compiler.h>
42 #include <asm/asm-compat.h>
43 #include <asm/synch.h>
44
45 /* PPC bit number conversion */
46 #define PPC_BITLSHIFT(be) (BITS_PER_LONG - 1 - (be))
47 #define PPC_BIT(bit) (1UL << PPC_BITLSHIFT(bit))
48 #define PPC_BITMASK(bs, be) ((PPC_BIT(bs) - PPC_BIT(be)) | PPC_BIT(bs))
49
50 /* Put a PPC bit into a "normal" bit position */
51 #define PPC_BITEXTRACT(bits, ppc_bit, dst_bit) \
52 ((((bits) >> PPC_BITLSHIFT(ppc_bit)) & 1) << (dst_bit))
53
54 #define PPC_BITLSHIFT32(be) (32 - 1 - (be))
55 #define PPC_BIT32(bit) (1UL << PPC_BITLSHIFT32(bit))
56 #define PPC_BITMASK32(bs, be) ((PPC_BIT32(bs) - PPC_BIT32(be))|PPC_BIT32(bs))
57
58 #define PPC_BITLSHIFT8(be) (8 - 1 - (be))
59 #define PPC_BIT8(bit) (1UL << PPC_BITLSHIFT8(bit))
60 #define PPC_BITMASK8(bs, be) ((PPC_BIT8(bs) - PPC_BIT8(be))|PPC_BIT8(bs))
61
62 #include <asm/barrier.h>
63
64 /* Macro for generating the ***_bits() functions */
65 #define DEFINE_BITOP(fn, op, prefix) \
66 static inline void fn(unsigned long mask, \
67 volatile unsigned long *_p) \
68 { \
69 unsigned long old; \
70 unsigned long *p = (unsigned long *)_p; \
71 __asm__ __volatile__ ( \
72 prefix \
73 "1:" PPC_LLARX "%0,0,%3,0\n" \
74 #op "%I2 %0,%0,%2\n" \
75 PPC_STLCX "%0,0,%3\n" \
76 "bne- 1b\n" \
77 : "=&r" (old), "+m" (*p) \
78 : "rK" (mask), "r" (p) \
79 : "cc", "memory"); \
80 }
81
82 DEFINE_BITOP(set_bits, or, "")
83 DEFINE_BITOP(change_bits, xor, "")
84
is_rlwinm_mask_valid(unsigned long x)85 static __always_inline bool is_rlwinm_mask_valid(unsigned long x)
86 {
87 if (!x)
88 return false;
89 if (x & 1)
90 x = ~x; // make the mask non-wrapping
91 x += x & -x; // adding the low set bit results in at most one bit set
92
93 return !(x & (x - 1));
94 }
95
96 #define DEFINE_CLROP(fn, prefix) \
97 static inline void fn(unsigned long mask, volatile unsigned long *_p) \
98 { \
99 unsigned long old; \
100 unsigned long *p = (unsigned long *)_p; \
101 \
102 if (IS_ENABLED(CONFIG_PPC32) && \
103 __builtin_constant_p(mask) && is_rlwinm_mask_valid(~mask)) {\
104 asm volatile ( \
105 prefix \
106 "1:" "lwarx %0,0,%3\n" \
107 "rlwinm %0,%0,0,%2\n" \
108 "stwcx. %0,0,%3\n" \
109 "bne- 1b\n" \
110 : "=&r" (old), "+m" (*p) \
111 : "n" (~mask), "r" (p) \
112 : "cc", "memory"); \
113 } else { \
114 asm volatile ( \
115 prefix \
116 "1:" PPC_LLARX "%0,0,%3,0\n" \
117 "andc %0,%0,%2\n" \
118 PPC_STLCX "%0,0,%3\n" \
119 "bne- 1b\n" \
120 : "=&r" (old), "+m" (*p) \
121 : "r" (mask), "r" (p) \
122 : "cc", "memory"); \
123 } \
124 }
125
126 DEFINE_CLROP(clear_bits, "")
DEFINE_CLROP(clear_bits_unlock,PPC_RELEASE_BARRIER)127 DEFINE_CLROP(clear_bits_unlock, PPC_RELEASE_BARRIER)
128
129 static inline void arch_set_bit(int nr, volatile unsigned long *addr)
130 {
131 set_bits(BIT_MASK(nr), addr + BIT_WORD(nr));
132 }
133
arch_clear_bit(int nr,volatile unsigned long * addr)134 static inline void arch_clear_bit(int nr, volatile unsigned long *addr)
135 {
136 clear_bits(BIT_MASK(nr), addr + BIT_WORD(nr));
137 }
138
arch_clear_bit_unlock(int nr,volatile unsigned long * addr)139 static inline void arch_clear_bit_unlock(int nr, volatile unsigned long *addr)
140 {
141 clear_bits_unlock(BIT_MASK(nr), addr + BIT_WORD(nr));
142 }
143
arch_change_bit(int nr,volatile unsigned long * addr)144 static inline void arch_change_bit(int nr, volatile unsigned long *addr)
145 {
146 change_bits(BIT_MASK(nr), addr + BIT_WORD(nr));
147 }
148
149 /* Like DEFINE_BITOP(), with changes to the arguments to 'op' and the output
150 * operands. */
151 #define DEFINE_TESTOP(fn, op, prefix, postfix, eh) \
152 static inline unsigned long fn( \
153 unsigned long mask, \
154 volatile unsigned long *_p) \
155 { \
156 unsigned long old, t; \
157 unsigned long *p = (unsigned long *)_p; \
158 __asm__ __volatile__ ( \
159 prefix \
160 "1:" PPC_LLARX "%0,0,%3,%4\n" \
161 #op "%I2 %1,%0,%2\n" \
162 PPC_STLCX "%1,0,%3\n" \
163 "bne- 1b\n" \
164 postfix \
165 : "=&r" (old), "=&r" (t) \
166 : "rK" (mask), "r" (p), "n" (eh) \
167 : "cc", "memory"); \
168 return (old & mask); \
169 }
170
171 DEFINE_TESTOP(test_and_set_bits, or, PPC_ATOMIC_ENTRY_BARRIER,
172 PPC_ATOMIC_EXIT_BARRIER, 0)
173 DEFINE_TESTOP(test_and_set_bits_lock, or, "",
174 PPC_ACQUIRE_BARRIER, IS_ENABLED(CONFIG_PPC64))
175 DEFINE_TESTOP(test_and_change_bits, xor, PPC_ATOMIC_ENTRY_BARRIER,
176 PPC_ATOMIC_EXIT_BARRIER, 0)
177
test_and_clear_bits(unsigned long mask,volatile unsigned long * _p)178 static inline unsigned long test_and_clear_bits(unsigned long mask, volatile unsigned long *_p)
179 {
180 unsigned long old, t;
181 unsigned long *p = (unsigned long *)_p;
182
183 if (IS_ENABLED(CONFIG_PPC32) &&
184 __builtin_constant_p(mask) && is_rlwinm_mask_valid(~mask)) {
185 asm volatile (
186 PPC_ATOMIC_ENTRY_BARRIER
187 "1:" "lwarx %0,0,%3\n"
188 "rlwinm %1,%0,0,%2\n"
189 "stwcx. %1,0,%3\n"
190 "bne- 1b\n"
191 PPC_ATOMIC_EXIT_BARRIER
192 : "=&r" (old), "=&r" (t)
193 : "n" (~mask), "r" (p)
194 : "cc", "memory");
195 } else {
196 asm volatile (
197 PPC_ATOMIC_ENTRY_BARRIER
198 "1:" PPC_LLARX "%0,0,%3,0\n"
199 "andc %1,%0,%2\n"
200 PPC_STLCX "%1,0,%3\n"
201 "bne- 1b\n"
202 PPC_ATOMIC_EXIT_BARRIER
203 : "=&r" (old), "=&r" (t)
204 : "r" (mask), "r" (p)
205 : "cc", "memory");
206 }
207
208 return (old & mask);
209 }
210
arch_test_and_set_bit(unsigned long nr,volatile unsigned long * addr)211 static inline int arch_test_and_set_bit(unsigned long nr,
212 volatile unsigned long *addr)
213 {
214 return test_and_set_bits(BIT_MASK(nr), addr + BIT_WORD(nr)) != 0;
215 }
216
arch_test_and_set_bit_lock(unsigned long nr,volatile unsigned long * addr)217 static inline int arch_test_and_set_bit_lock(unsigned long nr,
218 volatile unsigned long *addr)
219 {
220 return test_and_set_bits_lock(BIT_MASK(nr),
221 addr + BIT_WORD(nr)) != 0;
222 }
223
arch_test_and_clear_bit(unsigned long nr,volatile unsigned long * addr)224 static inline int arch_test_and_clear_bit(unsigned long nr,
225 volatile unsigned long *addr)
226 {
227 return test_and_clear_bits(BIT_MASK(nr), addr + BIT_WORD(nr)) != 0;
228 }
229
arch_test_and_change_bit(unsigned long nr,volatile unsigned long * addr)230 static inline int arch_test_and_change_bit(unsigned long nr,
231 volatile unsigned long *addr)
232 {
233 return test_and_change_bits(BIT_MASK(nr), addr + BIT_WORD(nr)) != 0;
234 }
235
236 #ifdef CONFIG_PPC64
237 static inline unsigned long
clear_bit_unlock_return_word(int nr,volatile unsigned long * addr)238 clear_bit_unlock_return_word(int nr, volatile unsigned long *addr)
239 {
240 unsigned long old, t;
241 unsigned long *p = (unsigned long *)addr + BIT_WORD(nr);
242 unsigned long mask = BIT_MASK(nr);
243
244 __asm__ __volatile__ (
245 PPC_RELEASE_BARRIER
246 "1:" PPC_LLARX "%0,0,%3,0\n"
247 "andc %1,%0,%2\n"
248 PPC_STLCX "%1,0,%3\n"
249 "bne- 1b\n"
250 : "=&r" (old), "=&r" (t)
251 : "r" (mask), "r" (p)
252 : "cc", "memory");
253
254 return old;
255 }
256
257 /*
258 * This is a special function for mm/filemap.c
259 * Bit 7 corresponds to PG_waiters.
260 */
261 #define arch_clear_bit_unlock_is_negative_byte(nr, addr) \
262 (clear_bit_unlock_return_word(nr, addr) & BIT_MASK(7))
263
264 #endif /* CONFIG_PPC64 */
265
266 #include <asm-generic/bitops/non-atomic.h>
267
arch___clear_bit_unlock(int nr,volatile unsigned long * addr)268 static inline void arch___clear_bit_unlock(int nr, volatile unsigned long *addr)
269 {
270 __asm__ __volatile__(PPC_RELEASE_BARRIER "" ::: "memory");
271 __clear_bit(nr, addr);
272 }
273
274 /*
275 * Return the zero-based bit position (LE, not IBM bit numbering) of
276 * the most significant 1-bit in a double word.
277 */
278 #define __ilog2(x) ilog2(x)
279
280 #include <asm-generic/bitops/ffz.h>
281
282 #include <asm-generic/bitops/builtin-__ffs.h>
283
284 #include <asm-generic/bitops/builtin-ffs.h>
285
286 /*
287 * fls: find last (most-significant) bit set.
288 * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
289 */
fls(unsigned int x)290 static __always_inline int fls(unsigned int x)
291 {
292 int lz;
293
294 if (__builtin_constant_p(x))
295 return x ? 32 - __builtin_clz(x) : 0;
296 asm("cntlzw %0,%1" : "=r" (lz) : "r" (x));
297 return 32 - lz;
298 }
299
300 #include <asm-generic/bitops/builtin-__fls.h>
301
302 /*
303 * 64-bit can do this using one cntlzd (count leading zeroes doubleword)
304 * instruction; for 32-bit we use the generic version, which does two
305 * 32-bit fls calls.
306 */
307 #ifdef CONFIG_PPC64
fls64(__u64 x)308 static __always_inline int fls64(__u64 x)
309 {
310 int lz;
311
312 if (__builtin_constant_p(x))
313 return x ? 64 - __builtin_clzll(x) : 0;
314 asm("cntlzd %0,%1" : "=r" (lz) : "r" (x));
315 return 64 - lz;
316 }
317 #else
318 #include <asm-generic/bitops/fls64.h>
319 #endif
320
321 #ifdef CONFIG_PPC64
322 unsigned int __arch_hweight8(unsigned int w);
323 unsigned int __arch_hweight16(unsigned int w);
324 unsigned int __arch_hweight32(unsigned int w);
325 unsigned long __arch_hweight64(__u64 w);
326 #include <asm-generic/bitops/const_hweight.h>
327 #else
328 #include <asm-generic/bitops/hweight.h>
329 #endif
330
331 /* wrappers that deal with KASAN instrumentation */
332 #include <asm-generic/bitops/instrumented-atomic.h>
333 #include <asm-generic/bitops/instrumented-lock.h>
334
335 /* Little-endian versions */
336 #include <asm-generic/bitops/le.h>
337
338 /* Bitmap functions for the ext2 filesystem */
339
340 #include <asm-generic/bitops/ext2-atomic-setbit.h>
341
342 #include <asm-generic/bitops/sched.h>
343
344 #endif /* __KERNEL__ */
345
346 #endif /* _ASM_POWERPC_BITOPS_H */
347