include/asm-mips/processor.h

   1 /* $Id: processor.h,v 1.18 1998/10/14 20:31:12 ralf Exp $
   2  *
   3  * This file is subject to the terms and conditions of the GNU General Public
   4  * License.  See the file "COPYING" in the main directory of this archive
   5  * for more details.
   6  *
   7  * Copyright (C) 1994 Waldorf GMBH
   8  * Copyright (C) 1995, 1996, 1997, 1998 Ralf Baechle
   9  * Modified further for R[236]000 compatibility by Paul M. Antoine
  10  */
  11 #ifndef __ASM_MIPS_PROCESSOR_H
  12 #define __ASM_MIPS_PROCESSOR_H
  13
  14 /*
  15  * Default implementation of macro that returns current
  16  * instruction pointer ("program counter").
  17  */
  18 #define current_text_addr() ({ __label__ _l; _l: &&_l;})
  19
  20 #if !defined (_LANGUAGE_ASSEMBLY)
  21 #include <asm/cachectl.h>
  22 #include <asm/mipsregs.h>
  23 #include <asm/reg.h>
  24 #include <asm/system.h>
  25
  26 struct mips_cpuinfo {
  27         unsigned long *pgd_quick;
  28         unsigned long *pte_quick;
  29         unsigned long pgtable_cache_sz;
  30 };
  31
  32 /*
  33  * System setup and hardware flags..
  34  * XXX: Should go into mips_cpuinfo.
  35  */
  36 extern char wait_available;             /* only available on R4[26]00 */
  37 extern char cyclecounter_available;     /* only available from R4000 upwards. */
  38 extern char dedicated_iv_available;     /* some embedded MIPS like Nevada */
  39 extern char vce_available;              /* Supports VCED / VCEI exceptions */
  40
  41 extern struct mips_cpuinfo boot_cpu_data;
  42 extern unsigned int vced_count, vcei_count;
  43
  44 #ifdef __SMP__
  45 extern struct mips_cpuinfo cpu_data[];
  46 #define current_cpu_data cpu_data[smp_processor_id()]
  47 #else
  48 #define cpu_data &boot_cpu_data
  49 #define current_cpu_data boot_cpu_data
  50 #endif
  51
  52 /*
  53  * Bus types (default is ISA, but people can check others with these..)
  54  * MCA_bus hardcoded to 0 for now.
  55  *
  56  * This needs to be extended since MIPS systems are being delivered with
  57  * numerous different types of bus systems.
  58  */
  59 extern int EISA_bus;
  60 #define MCA_bus 0
  61 #define MCA_bus__is_a_macro /* for versions in ksyms.c */
  62
  63 /*
  64  * MIPS has no problems with write protection
  65  */
  66 #define wp_works_ok 1
  67 #define wp_works_ok__is_a_macro /* for versions in ksyms.c */
  68
  69 /* Lazy FPU handling on uni-processor */
  70 extern struct task_struct *last_task_used_math;
  71
  72 /*
  73  * User space process size: 2GB. This is hardcoded into a few places,
  74  * so don't change it unless you know what you are doing.  TASK_SIZE
  75  * for a 64 bit kernel expandable to 8192EB, of which the current MIPS
  76  * implementations will "only" be able to use 1TB ...
  77  */
  78 #define TASK_SIZE       (0x80000000UL)
  79
  80 /* This decides where the kernel will search for a free chunk of vm
  81  * space during mmap's.
  82  */
  83 #define TASK_UNMAPPED_BASE      (TASK_SIZE / 3)
  84
  85 /*
  86  * Size of io_bitmap in longwords: 32 is ports 0-0x3ff.
  87  */
  88 #define IO_BITMAP_SIZE  32
  89
  90 #define NUM_FPU_REGS    32
  91
  92 struct mips_fpu_hard_struct {
  93         double fp_regs[NUM_FPU_REGS];
  94         unsigned int control;
  95 };
  96
  97 /*
  98  * FIXME: no fpu emulator yet (but who cares anyway?)
  99  */
 100 struct mips_fpu_soft_struct {
 101         long    dummy;
 102 };
 103
 104 union mips_fpu_union {
 105         struct mips_fpu_hard_struct hard;
 106         struct mips_fpu_soft_struct soft;
 107 };
 108
 109 #define INIT_FPU { \
 110         {{0,},} \
 111 }
 112
 113 typedef struct {
 114         unsigned long seg;
 115 } mm_segment_t;
 116
 117 /*
 118  * If you change thread_struct remember to change the #defines below too!
 119  */
 120 struct thread_struct {
 121         /* Saved main processor registers. */
 122         unsigned long reg16;
 123         unsigned long reg17, reg18, reg19, reg20, reg21, reg22, reg23;
 124         unsigned long reg29, reg30, reg31;
 125
 126         /* Saved cp0 stuff. */
 127         unsigned long cp0_status;
 128
 129         /* Saved fpu/fpu emulator stuff. */
 130         union mips_fpu_union fpu;
 131
 132         /* Other stuff associated with the thread. */
 133         unsigned long cp0_badvaddr;     /* Last user fault */
 134         unsigned long cp0_baduaddr;     /* Last kernel fault accessing USEG */
 135         unsigned long error_code;
 136         unsigned long trap_no;
 137         unsigned long pg_dir;                   /* used in tlb refill    */
 138 #define MF_FIXADE 1                     /* Fix address errors in software */
 139 #define MF_LOGADE 2                     /* Log address errors to syslog */
 140         unsigned long mflags;
 141         mm_segment_t current_ds;
 142         unsigned long irix_trampoline;  /* Wheee... */
 143         unsigned long irix_oldctx;
 144 };
 145
 146 #endif /* !defined (_LANGUAGE_ASSEMBLY) */
 147
 148 #define INIT_MMAP { &init_mm, KSEG0, KSEG1, NULL, PAGE_SHARED, \
 149                     VM_READ | VM_WRITE | VM_EXEC, 1, NULL, NULL }
 150
 151 #define INIT_TSS  { \
 152         /* \
 153          * saved main processor registers \
 154          */ \
 155         0, 0, 0, 0, 0, 0, 0, 0, \
 156                        0, 0, 0, \
 157         /* \
 158          * saved cp0 stuff \
 159          */ \
 160         0, \
 161         /* \
 162          * saved fpu/fpu emulator stuff \
 163          */ \
 164         INIT_FPU, \
 165         /* \
 166          * Other stuff associated with the process \
 167          */ \
 168         0, 0, 0, 0, (unsigned long) swapper_pg_dir, \
 169         /* \
 170          * For now the default is to fix address errors \
 171          */ \
 172         MF_FIXADE, { 0 }, 0, 0 \
 173 }
 174
 175 #ifdef __KERNEL__
 176
 177 #define KERNEL_STACK_SIZE 8192
 178
 179 #if !defined (_LANGUAGE_ASSEMBLY)
 180
 181 /* Free all resources held by a thread. */
 182 extern void release_thread(struct task_struct *);
 183 extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
 184
 185 /* Copy and release all segment info associated with a VM */
 186 #define copy_segments(nr, p, mm) do { } while(0)
 187 #define release_segments(mm) do { } while(0)
 188 #define forget_segments()               do { } while (0)
 189
 190 /*
 191  * Return saved PC of a blocked thread.
 192  */
 193 extern inline unsigned long thread_saved_pc(struct thread_struct *t)
 194 {
 195         extern void ret_from_sys_call(void);
 196
 197         /* New born processes are a special case */
 198         if (t->reg31 == (unsigned long) ret_from_sys_call)
 199                 return t->reg31;
 200
 201         return ((unsigned long*)t->reg29)[17];
 202 }
 203
 204 /*
 205  * Do necessary setup to start up a newly executed thread.
 206  */
 207 extern void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp);
 208
 209 /* Allocation and freeing of basic task resources. */
 210 /*
 211  * NOTE! The task struct and the stack go together
 212  */
 213 #define alloc_task_struct() \
 214         ((struct task_struct *) __get_free_pages(GFP_KERNEL,1))
 215 #define free_task_struct(p)     free_pages((unsigned long)(p),1)
 216
 217 #define init_task       (init_task_union.task)
 218 #define init_stack      (init_task_union.stack)
 219
 220 #endif /* !defined (_LANGUAGE_ASSEMBLY) */
 221 #endif /* __KERNEL__ */
 222
 223 /*
 224  * Return_address is a replacement for __builtin_return_address(count)
 225  * which on certain architectures cannot reasonably be implemented in GCC
 226  * (MIPS, Alpha) or is unuseable with -fomit-frame-pointer (i386).
 227  * Note that __builtin_return_address(x>=1) is forbidden because GCC
 228  * aborts compilation on some CPUs.  It's simply not possible to unwind
 229  * some CPU's stackframes.
 230  */
 231 #if (__GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 8))
 232 /*
 233  * __builtin_return_address works only for non-leaf functions.  We avoid the
 234  * overhead of a function call by forcing the compiler to save the return
 235  * address register on the stack.
 236  */
 237 #define return_address() ({__asm__ __volatile__("":::"$31");__builtin_return_address(0);})
 238 #else
 239 /*
 240  * __builtin_return_address is not implemented at all.  Calling it
 241  * will return senseless values.  Return NULL which at least is an obviously
 242  * senseless value.
 243  */
 244 #define return_address() NULL
 245 #endif
 246
 247 #endif /* __ASM_MIPS_PROCESSOR_H */