arch/mips/include/asm/system.h

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 1994, 95, 96, 97, 98, 99, 2003, 06 by Ralf Baechle
   7  * Copyright (C) 1996 by Paul M. Antoine
   8  * Copyright (C) 1999 Silicon Graphics
   9  * Kevin D. Kissell, kevink@mips.org and Carsten Langgaard, carstenl@mips.com
  10  * Copyright (C) 2000 MIPS Technologies, Inc.
  11  */
  12 #ifndef _ASM_SYSTEM_H
  13 #define _ASM_SYSTEM_H
  14
  15 #include <linux/kernel.h>
  16 #include <linux/types.h>
  17 #include <linux/irqflags.h>
  18
  19 #include <asm/addrspace.h>
  20 #include <asm/barrier.h>
  21 #include <asm/cmpxchg.h>
  22 #include <asm/cpu-features.h>
  23 #include <asm/dsp.h>
  24 #include <asm/watch.h>
  25 #include <asm/war.h>
  26
  27
  28 /*
  29  * switch_to(n) should switch tasks to task nr n, first
  30  * checking that n isn't the current task, in which case it does nothing.
  31  */
  32 extern asmlinkage void *resume(void *last, void *next, void *next_ti);
  33
  34 struct task_struct;
  35
  36 extern unsigned int ll_bit;
  37 extern struct task_struct *ll_task;
  38
  39 #ifdef CONFIG_MIPS_MT_FPAFF
  40
  41 /*
  42  * Handle the scheduler resume end of FPU affinity management.  We do this
  43  * inline to try to keep the overhead down. If we have been forced to run on
  44  * a "CPU" with an FPU because of a previous high level of FP computation,
  45  * but did not actually use the FPU during the most recent time-slice (CU1
  46  * isn't set), we undo the restriction on cpus_allowed.
  47  *
  48  * We're not calling set_cpus_allowed() here, because we have no need to
  49  * force prompt migration - we're already switching the current CPU to a
  50  * different thread.
  51  */
  52
  53 #define __mips_mt_fpaff_switch_to(prev)                                 \
  54 do {                                                                    \
  55         struct thread_info *__prev_ti = task_thread_info(prev);         \
  56                                                                         \
  57         if (cpu_has_fpu &&                                              \
  58             test_ti_thread_flag(__prev_ti, TIF_FPUBOUND) &&             \
  59             (!(KSTK_STATUS(prev) & ST0_CU1))) {                         \
  60                 clear_ti_thread_flag(__prev_ti, TIF_FPUBOUND);          \
  61                 prev->cpus_allowed = prev->thread.user_cpus_allowed;    \
  62         }                                                               \
  63         next->thread.emulated_fp = 0;                                   \
  64 } while(0)
  65
  66 #else
  67 #define __mips_mt_fpaff_switch_to(prev) do { (void) (prev); } while (0)
  68 #endif
  69
  70 #define __clear_software_ll_bit()                                       \
  71 do {                                                                    \
  72         if (!__builtin_constant_p(cpu_has_llsc) || !cpu_has_llsc)       \
  73                 ll_bit = 0;                                             \
  74 } while (0)
  75
  76 #define switch_to(prev, next, last)                                     \
  77 do {                                                                    \
  78         __mips_mt_fpaff_switch_to(prev);                                \
  79         if (cpu_has_dsp)                                                \
  80                 __save_dsp(prev);                                       \
  81         __clear_software_ll_bit();                                      \
  82         (last) = resume(prev, next, task_thread_info(next));            \
  83 } while (0)
  84
  85 #define finish_arch_switch(prev)                                        \
  86 do {                                                                    \
  87         if (cpu_has_dsp)                                                \
  88                 __restore_dsp(current);                                 \
  89         if (cpu_has_userlocal)                                          \
  90                 write_c0_userlocal(current_thread_info()->tp_value);    \
  91         __restore_watch();                                              \
  92 } while (0)
  93
  94 static inline unsigned long __xchg_u32(volatile int * m, unsigned int val)
  95 {
  96         __u32 retval;
  97
  98         smp_mb__before_llsc();
  99
 100         if (kernel_uses_llsc && R10000_LLSC_WAR) {
 101                 unsigned long dummy;
 102
 103                 __asm__ __volatile__(
 104                 "       .set    mips3                                   \n"
 105                 "1:     ll      %0, %3                  # xchg_u32      \n"
 106                 "       .set    mips0                                   \n"
 107                 "       move    %2, %z4                                 \n"
 108                 "       .set    mips3                                   \n"
 109                 "       sc      %2, %1                                  \n"
 110                 "       beqzl   %2, 1b                                  \n"
 111                 "       .set    mips0                                   \n"
 112                 : "=&r" (retval), "=m" (*m), "=&r" (dummy)
 113                 : "R" (*m), "Jr" (val)
 114                 : "memory");
 115         } else if (kernel_uses_llsc) {
 116                 unsigned long dummy;
 117
 118                 do {
 119                         __asm__ __volatile__(
 120                         "       .set    mips3                           \n"
 121                         "       ll      %0, %3          # xchg_u32      \n"
 122                         "       .set    mips0                           \n"
 123                         "       move    %2, %z4                         \n"
 124                         "       .set    mips3                           \n"
 125                         "       sc      %2, %1                          \n"
 126                         "       .set    mips0                           \n"
 127                         : "=&r" (retval), "=m" (*m), "=&r" (dummy)
 128                         : "R" (*m), "Jr" (val)
 129                         : "memory");
 130                 } while (unlikely(!dummy));
 131         } else {
 132                 unsigned long flags;
 133
 134                 raw_local_irq_save(flags);
 135                 retval = *m;
 136                 *m = val;
 137                 raw_local_irq_restore(flags);   /* implies memory barrier  */
 138         }
 139
 140         smp_llsc_mb();
 141
 142         return retval;
 143 }
 144
 145 #ifdef CONFIG_64BIT
 146 static inline __u64 __xchg_u64(volatile __u64 * m, __u64 val)
 147 {
 148         __u64 retval;
 149
 150         smp_mb__before_llsc();
 151
 152         if (kernel_uses_llsc && R10000_LLSC_WAR) {
 153                 unsigned long dummy;
 154
 155                 __asm__ __volatile__(
 156                 "       .set    mips3                                   \n"
 157                 "1:     lld     %0, %3                  # xchg_u64      \n"
 158                 "       move    %2, %z4                                 \n"
 159                 "       scd     %2, %1                                  \n"
 160                 "       beqzl   %2, 1b                                  \n"
 161                 "       .set    mips0                                   \n"
 162                 : "=&r" (retval), "=m" (*m), "=&r" (dummy)
 163                 : "R" (*m), "Jr" (val)
 164                 : "memory");
 165         } else if (kernel_uses_llsc) {
 166                 unsigned long dummy;
 167
 168                 do {
 169                         __asm__ __volatile__(
 170                         "       .set    mips3                           \n"
 171                         "       lld     %0, %3          # xchg_u64      \n"
 172                         "       move    %2, %z4                         \n"
 173                         "       scd     %2, %1                          \n"
 174                         "       .set    mips0                           \n"
 175                         : "=&r" (retval), "=m" (*m), "=&r" (dummy)
 176                         : "R" (*m), "Jr" (val)
 177                         : "memory");
 178                 } while (unlikely(!dummy));
 179         } else {
 180                 unsigned long flags;
 181
 182                 raw_local_irq_save(flags);
 183                 retval = *m;
 184                 *m = val;
 185                 raw_local_irq_restore(flags);   /* implies memory barrier  */
 186         }
 187
 188         smp_llsc_mb();
 189
 190         return retval;
 191 }
 192 #else
 193 extern __u64 __xchg_u64_unsupported_on_32bit_kernels(volatile __u64 * m, __u64 val);
 194 #define __xchg_u64 __xchg_u64_unsupported_on_32bit_kernels
 195 #endif
 196
 197 static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
 198 {
 199         switch (size) {
 200         case 4:
 201                 return __xchg_u32(ptr, x);
 202         case 8:
 203                 return __xchg_u64(ptr, x);
 204         }
 205
 206         return x;
 207 }
 208
 209 #define xchg(ptr, x)                                                    \
 210 ({                                                                      \
 211         BUILD_BUG_ON(sizeof(*(ptr)) & ~0xc);                            \
 212                                                                         \
 213         ((__typeof__(*(ptr)))                                           \
 214                 __xchg((unsigned long)(x), (ptr), sizeof(*(ptr))));     \
 215 })
 216
 217 extern void set_handler(unsigned long offset, void *addr, unsigned long len);
 218 extern void set_uncached_handler(unsigned long offset, void *addr, unsigned long len);
 219
 220 typedef void (*vi_handler_t)(void);
 221 extern void *set_vi_handler(int n, vi_handler_t addr);
 222
 223 extern void *set_except_vector(int n, void *addr);
 224 extern unsigned long ebase;
 225 extern void per_cpu_trap_init(void);
 226
 227 /*
 228  * See include/asm-ia64/system.h; prevents deadlock on SMP
 229  * systems.
 230  */
 231 #define __ARCH_WANT_UNLOCKED_CTXSW
 232
 233 extern unsigned long arch_align_stack(unsigned long sp);
 234
 235 #endif /* _ASM_SYSTEM_H */