[PATCH] ARM SMP: Use exclusive load/store for __xchg
[deliverable/linux.git] / include / asm-arm / system.h
1 #ifndef __ASM_ARM_SYSTEM_H
2 #define __ASM_ARM_SYSTEM_H
3
4 #ifdef __KERNEL__
5
6 #include <linux/config.h>
7
8 #define CPU_ARCH_UNKNOWN 0
9 #define CPU_ARCH_ARMv3 1
10 #define CPU_ARCH_ARMv4 2
11 #define CPU_ARCH_ARMv4T 3
12 #define CPU_ARCH_ARMv5 4
13 #define CPU_ARCH_ARMv5T 5
14 #define CPU_ARCH_ARMv5TE 6
15 #define CPU_ARCH_ARMv5TEJ 7
16 #define CPU_ARCH_ARMv6 8
17
18 /*
19 * CR1 bits (CP#15 CR1)
20 */
21 #define CR_M (1 << 0) /* MMU enable */
22 #define CR_A (1 << 1) /* Alignment abort enable */
23 #define CR_C (1 << 2) /* Dcache enable */
24 #define CR_W (1 << 3) /* Write buffer enable */
25 #define CR_P (1 << 4) /* 32-bit exception handler */
26 #define CR_D (1 << 5) /* 32-bit data address range */
27 #define CR_L (1 << 6) /* Implementation defined */
28 #define CR_B (1 << 7) /* Big endian */
29 #define CR_S (1 << 8) /* System MMU protection */
30 #define CR_R (1 << 9) /* ROM MMU protection */
31 #define CR_F (1 << 10) /* Implementation defined */
32 #define CR_Z (1 << 11) /* Implementation defined */
33 #define CR_I (1 << 12) /* Icache enable */
34 #define CR_V (1 << 13) /* Vectors relocated to 0xffff0000 */
35 #define CR_RR (1 << 14) /* Round Robin cache replacement */
36 #define CR_L4 (1 << 15) /* LDR pc can set T bit */
37 #define CR_DT (1 << 16)
38 #define CR_IT (1 << 18)
39 #define CR_ST (1 << 19)
40 #define CR_FI (1 << 21) /* Fast interrupt (lower latency mode) */
41 #define CR_U (1 << 22) /* Unaligned access operation */
42 #define CR_XP (1 << 23) /* Extended page tables */
43 #define CR_VE (1 << 24) /* Vectored interrupts */
44
45 #define CPUID_ID 0
46 #define CPUID_CACHETYPE 1
47 #define CPUID_TCM 2
48 #define CPUID_TLBTYPE 3
49
50 #define read_cpuid(reg) \
51 ({ \
52 unsigned int __val; \
53 asm("mrc p15, 0, %0, c0, c0, " __stringify(reg) \
54 : "=r" (__val) \
55 : \
56 : "cc"); \
57 __val; \
58 })
59
60 /*
61 * This is used to ensure the compiler did actually allocate the register we
62 * asked it for some inline assembly sequences. Apparently we can't trust
63 * the compiler from one version to another so a bit of paranoia won't hurt.
64 * This string is meant to be concatenated with the inline asm string and
65 * will cause compilation to stop on mismatch.
66 * (for details, see gcc PR 15089)
67 */
68 #define __asmeq(x, y) ".ifnc " x "," y " ; .err ; .endif\n\t"
69
70 #ifndef __ASSEMBLY__
71
72 #include <linux/linkage.h>
73
74 struct thread_info;
75 struct task_struct;
76
77 /* information about the system we're running on */
78 extern unsigned int system_rev;
79 extern unsigned int system_serial_low;
80 extern unsigned int system_serial_high;
81 extern unsigned int mem_fclk_21285;
82
83 struct pt_regs;
84
85 void die(const char *msg, struct pt_regs *regs, int err)
86 __attribute__((noreturn));
87
88 struct siginfo;
89 void notify_die(const char *str, struct pt_regs *regs, struct siginfo *info,
90 unsigned long err, unsigned long trap);
91
92 void hook_fault_code(int nr, int (*fn)(unsigned long, unsigned int,
93 struct pt_regs *),
94 int sig, const char *name);
95
96 #include <asm/proc-fns.h>
97
98 #define xchg(ptr,x) \
99 ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
100
101 #define tas(ptr) (xchg((ptr),1))
102
103 extern asmlinkage void __backtrace(void);
104 extern asmlinkage void c_backtrace(unsigned long fp, int pmode);
105 extern void show_pte(struct mm_struct *mm, unsigned long addr);
106 extern void __show_regs(struct pt_regs *);
107
108 extern int cpu_architecture(void);
109 extern void cpu_init(void);
110
111 #define set_cr(x) \
112 __asm__ __volatile__( \
113 "mcr p15, 0, %0, c1, c0, 0 @ set CR" \
114 : : "r" (x) : "cc")
115
116 #define get_cr() \
117 ({ \
118 unsigned int __val; \
119 __asm__ __volatile__( \
120 "mrc p15, 0, %0, c1, c0, 0 @ get CR" \
121 : "=r" (__val) : : "cc"); \
122 __val; \
123 })
124
125 extern unsigned long cr_no_alignment; /* defined in entry-armv.S */
126 extern unsigned long cr_alignment; /* defined in entry-armv.S */
127
128 #define UDBG_UNDEFINED (1 << 0)
129 #define UDBG_SYSCALL (1 << 1)
130 #define UDBG_BADABORT (1 << 2)
131 #define UDBG_SEGV (1 << 3)
132 #define UDBG_BUS (1 << 4)
133
134 extern unsigned int user_debug;
135
136 #if __LINUX_ARM_ARCH__ >= 4
137 #define vectors_high() (cr_alignment & CR_V)
138 #else
139 #define vectors_high() (0)
140 #endif
141
142 #define mb() __asm__ __volatile__ ("" : : : "memory")
143 #define rmb() mb()
144 #define wmb() mb()
145 #define read_barrier_depends() do { } while(0)
146 #define set_mb(var, value) do { var = value; mb(); } while (0)
147 #define set_wmb(var, value) do { var = value; wmb(); } while (0)
148 #define nop() __asm__ __volatile__("mov\tr0,r0\t@ nop\n\t");
149
150 /*
151 * switch_mm() may do a full cache flush over the context switch,
152 * so enable interrupts over the context switch to avoid high
153 * latency.
154 */
155 #define __ARCH_WANT_INTERRUPTS_ON_CTXSW
156
157 /*
158 * switch_to(prev, next) should switch from task `prev' to `next'
159 * `prev' will never be the same as `next'. schedule() itself
160 * contains the memory barrier to tell GCC not to cache `current'.
161 */
162 extern struct task_struct *__switch_to(struct task_struct *, struct thread_info *, struct thread_info *);
163
164 #define switch_to(prev,next,last) \
165 do { \
166 last = __switch_to(prev,prev->thread_info,next->thread_info); \
167 } while (0)
168
169 /*
170 * CPU interrupt mask handling.
171 */
172 #if __LINUX_ARM_ARCH__ >= 6
173
174 #define local_irq_save(x) \
175 ({ \
176 __asm__ __volatile__( \
177 "mrs %0, cpsr @ local_irq_save\n" \
178 "cpsid i" \
179 : "=r" (x) : : "memory", "cc"); \
180 })
181
182 #define local_irq_enable() __asm__("cpsie i @ __sti" : : : "memory", "cc")
183 #define local_irq_disable() __asm__("cpsid i @ __cli" : : : "memory", "cc")
184 #define local_fiq_enable() __asm__("cpsie f @ __stf" : : : "memory", "cc")
185 #define local_fiq_disable() __asm__("cpsid f @ __clf" : : : "memory", "cc")
186
187 #else
188
189 /*
190 * Save the current interrupt enable state & disable IRQs
191 */
192 #define local_irq_save(x) \
193 ({ \
194 unsigned long temp; \
195 (void) (&temp == &x); \
196 __asm__ __volatile__( \
197 "mrs %0, cpsr @ local_irq_save\n" \
198 " orr %1, %0, #128\n" \
199 " msr cpsr_c, %1" \
200 : "=r" (x), "=r" (temp) \
201 : \
202 : "memory", "cc"); \
203 })
204
205 /*
206 * Enable IRQs
207 */
208 #define local_irq_enable() \
209 ({ \
210 unsigned long temp; \
211 __asm__ __volatile__( \
212 "mrs %0, cpsr @ local_irq_enable\n" \
213 " bic %0, %0, #128\n" \
214 " msr cpsr_c, %0" \
215 : "=r" (temp) \
216 : \
217 : "memory", "cc"); \
218 })
219
220 /*
221 * Disable IRQs
222 */
223 #define local_irq_disable() \
224 ({ \
225 unsigned long temp; \
226 __asm__ __volatile__( \
227 "mrs %0, cpsr @ local_irq_disable\n" \
228 " orr %0, %0, #128\n" \
229 " msr cpsr_c, %0" \
230 : "=r" (temp) \
231 : \
232 : "memory", "cc"); \
233 })
234
235 /*
236 * Enable FIQs
237 */
238 #define local_fiq_enable() \
239 ({ \
240 unsigned long temp; \
241 __asm__ __volatile__( \
242 "mrs %0, cpsr @ stf\n" \
243 " bic %0, %0, #64\n" \
244 " msr cpsr_c, %0" \
245 : "=r" (temp) \
246 : \
247 : "memory", "cc"); \
248 })
249
250 /*
251 * Disable FIQs
252 */
253 #define local_fiq_disable() \
254 ({ \
255 unsigned long temp; \
256 __asm__ __volatile__( \
257 "mrs %0, cpsr @ clf\n" \
258 " orr %0, %0, #64\n" \
259 " msr cpsr_c, %0" \
260 : "=r" (temp) \
261 : \
262 : "memory", "cc"); \
263 })
264
265 #endif
266
267 /*
268 * Save the current interrupt enable state.
269 */
270 #define local_save_flags(x) \
271 ({ \
272 __asm__ __volatile__( \
273 "mrs %0, cpsr @ local_save_flags" \
274 : "=r" (x) : : "memory", "cc"); \
275 })
276
277 /*
278 * restore saved IRQ & FIQ state
279 */
280 #define local_irq_restore(x) \
281 __asm__ __volatile__( \
282 "msr cpsr_c, %0 @ local_irq_restore\n" \
283 : \
284 : "r" (x) \
285 : "memory", "cc")
286
287 #define irqs_disabled() \
288 ({ \
289 unsigned long flags; \
290 local_save_flags(flags); \
291 (int)(flags & PSR_I_BIT); \
292 })
293
294 #ifdef CONFIG_SMP
295
296 #define smp_mb() mb()
297 #define smp_rmb() rmb()
298 #define smp_wmb() wmb()
299 #define smp_read_barrier_depends() read_barrier_depends()
300
301 #else
302
303 #define smp_mb() barrier()
304 #define smp_rmb() barrier()
305 #define smp_wmb() barrier()
306 #define smp_read_barrier_depends() do { } while(0)
307
308 #endif /* CONFIG_SMP */
309
310 #if defined(CONFIG_CPU_SA1100) || defined(CONFIG_CPU_SA110)
311 /*
312 * On the StrongARM, "swp" is terminally broken since it bypasses the
313 * cache totally. This means that the cache becomes inconsistent, and,
314 * since we use normal loads/stores as well, this is really bad.
315 * Typically, this causes oopsen in filp_close, but could have other,
316 * more disasterous effects. There are two work-arounds:
317 * 1. Disable interrupts and emulate the atomic swap
318 * 2. Clean the cache, perform atomic swap, flush the cache
319 *
320 * We choose (1) since its the "easiest" to achieve here and is not
321 * dependent on the processor type.
322 *
323 * NOTE that this solution won't work on an SMP system, so explcitly
324 * forbid it here.
325 */
326 #define swp_is_buggy
327 #endif
328
329 static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size)
330 {
331 extern void __bad_xchg(volatile void *, int);
332 unsigned long ret;
333 #ifdef swp_is_buggy
334 unsigned long flags;
335 #endif
336 #if __LINUX_ARM_ARCH__ >= 6
337 unsigned int tmp;
338 #endif
339
340 switch (size) {
341 #if __LINUX_ARM_ARCH__ >= 6
342 case 1:
343 asm volatile("@ __xchg1\n"
344 "1: ldrexb %0, [%3]\n"
345 " strexb %1, %2, [%3]\n"
346 " teq %1, #0\n"
347 " bne 1b"
348 : "=&r" (ret), "=&r" (tmp)
349 : "r" (x), "r" (ptr)
350 : "memory", "cc");
351 break;
352 case 4:
353 asm volatile("@ __xchg4\n"
354 "1: ldrex %0, [%3]\n"
355 " strex %1, %2, [%3]\n"
356 " teq %1, #0\n"
357 " bne 1b"
358 : "=&r" (ret), "=&r" (tmp)
359 : "r" (x), "r" (ptr)
360 : "memory", "cc");
361 break;
362 #elif defined(swp_is_buggy)
363 #ifdef CONFIG_SMP
364 #error SMP is not supported on this platform
365 #endif
366 case 1:
367 local_irq_save(flags);
368 ret = *(volatile unsigned char *)ptr;
369 *(volatile unsigned char *)ptr = x;
370 local_irq_restore(flags);
371 break;
372
373 case 4:
374 local_irq_save(flags);
375 ret = *(volatile unsigned long *)ptr;
376 *(volatile unsigned long *)ptr = x;
377 local_irq_restore(flags);
378 break;
379 #else
380 case 1:
381 asm volatile("@ __xchg1\n"
382 " swpb %0, %1, [%2]"
383 : "=&r" (ret)
384 : "r" (x), "r" (ptr)
385 : "memory", "cc");
386 break;
387 case 4:
388 asm volatile("@ __xchg4\n"
389 " swp %0, %1, [%2]"
390 : "=&r" (ret)
391 : "r" (x), "r" (ptr)
392 : "memory", "cc");
393 break;
394 #endif
395 default:
396 __bad_xchg(ptr, size), ret = 0;
397 break;
398 }
399
400 return ret;
401 }
402
403 #endif /* __ASSEMBLY__ */
404
405 #define arch_align_stack(x) (x)
406
407 #endif /* __KERNEL__ */
408
409 #endif
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