include/asm-mips/processor.h

   1 /* $Id: processor.h,v 1.25 2000/02/05 06:47:37 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  * Copyright (C) 1996 Paul M. Antoine
  10  * Copyright (C) 1999 Silicon Graphics, Inc.
  11  */
  12 #ifndef _ASM_PROCESSOR_H
  13 #define _ASM_PROCESSOR_H
  14
  15 #include <linux/config.h>
  16
  17 #include <asm/isadep.h>
  18
  19 /*
  20  * Default implementation of macro that returns current
  21  * instruction pointer ("program counter").
  22  */
  23 #define current_text_addr() ({ __label__ _l; _l: &&_l;})
  24
  25 #if !defined (_LANGUAGE_ASSEMBLY)
  26 #include <linux/threads.h>
  27 #include <asm/cachectl.h>
  28 #include <asm/mipsregs.h>
  29 #include <asm/reg.h>
  30 #include <asm/system.h>
  31
  32 struct mips_cpuinfo {
  33         unsigned long *pgd_quick;
  34         unsigned long *pte_quick;
  35         unsigned long pgtable_cache_sz;
  36 };
  37
  38 /*
  39  * System setup and hardware flags..
  40  * XXX: Should go into mips_cpuinfo.
  41  */
  42 extern void (*cpu_wait)(void);  /* only available on R4[26]00 and R3081 */
  43 extern void r3081_wait(void);
  44 extern void r4k_wait(void);
  45 extern char cyclecounter_available;     /* only available from R4000 upwards. */
  46 extern char dedicated_iv_available;     /* some embedded MIPS like Nevada */
  47 extern char vce_available;              /* Supports VCED / VCEI exceptions */
  48
  49 extern struct mips_cpuinfo boot_cpu_data;
  50 extern unsigned int vced_count, vcei_count;
  51
  52 #ifdef CONFIG_SMP
  53 extern struct mips_cpuinfo cpu_data[];
  54 #define current_cpu_data cpu_data[smp_processor_id()]
  55 #else
  56 #define cpu_data &boot_cpu_data
  57 #define current_cpu_data boot_cpu_data
  58 #endif
  59
  60 /*
  61  * Bus types (default is ISA, but people can check others with these..)
  62  * MCA_bus hardcoded to 0 for now.
  63  *
  64  * This needs to be extended since MIPS systems are being delivered with
  65  * numerous different types of bus systems.
  66  */
  67 extern int EISA_bus;
  68 #define MCA_bus 0
  69 #define MCA_bus__is_a_macro /* for versions in ksyms.c */
  70
  71 /*
  72  * MIPS has no problems with write protection
  73  */
  74 #define wp_works_ok 1
  75 #define wp_works_ok__is_a_macro /* for versions in ksyms.c */
  76
  77 /* Lazy FPU handling on uni-processor */
  78 extern struct task_struct *last_task_used_math;
  79
  80 /*
  81  * User space process size: 2GB. This is hardcoded into a few places,
  82  * so don't change it unless you know what you are doing.  TASK_SIZE
  83  * for a 64 bit kernel expandable to 8192EB, of which the current MIPS
  84  * implementations will "only" be able to use 1TB ...
  85  */
  86 #define TASK_SIZE       (0x80000000UL)
  87
  88 /* This decides where the kernel will search for a free chunk of vm
  89  * space during mmap's.
  90  */
  91 #define TASK_UNMAPPED_BASE      (TASK_SIZE / 3)
  92
  93 /*
  94  * Size of io_bitmap in longwords: 32 is ports 0-0x3ff.
  95  */
  96 #define IO_BITMAP_SIZE  32
  97
  98 #define NUM_FPU_REGS    32
  99
 100 struct mips_fpu_hard_struct {
 101         unsigned int fp_regs[NUM_FPU_REGS];
 102         unsigned int control;
 103 } __attribute__((aligned(8)));
 104
 105 /*
 106  * FIXME: no fpu emulator yet (but who cares anyway?)
 107  */
 108 struct mips_fpu_soft_struct {
 109         long    dummy;
 110 };
 111
 112 union mips_fpu_union {
 113         struct mips_fpu_hard_struct hard;
 114         struct mips_fpu_soft_struct soft;
 115 };
 116
 117 #define INIT_FPU { \
 118         {{0,},} \
 119 }
 120
 121 typedef struct {
 122         unsigned long seg;
 123 } mm_segment_t;
 124
 125 /*
 126  * If you change thread_struct remember to change the #defines below too!
 127  */
 128 struct thread_struct {
 129         /* Saved main processor registers. */
 130         unsigned long reg16;
 131         unsigned long reg17, reg18, reg19, reg20, reg21, reg22, reg23;
 132         unsigned long reg29, reg30, reg31;
 133
 134         /* Saved cp0 stuff. */
 135         unsigned long cp0_status;
 136
 137         /* Saved fpu/fpu emulator stuff. */
 138         union mips_fpu_union fpu;
 139
 140         /* Other stuff associated with the thread. */
 141         unsigned long cp0_badvaddr;     /* Last user fault */
 142         unsigned long cp0_baduaddr;     /* Last kernel fault accessing USEG */
 143         unsigned long error_code;
 144         unsigned long trap_no;
 145 #define MF_FIXADE 1                     /* Fix address errors in software */
 146 #define MF_LOGADE 2                     /* Log address errors to syslog */
 147         unsigned long mflags;
 148         mm_segment_t current_ds;
 149         unsigned long irix_trampoline;  /* Wheee... */
 150         unsigned long irix_oldctx;
 151 };
 152
 153 #endif /* !defined (_LANGUAGE_ASSEMBLY) */
 154
 155 #define INIT_MMAP { &init_mm, KSEG0, KSEG1, NULL, PAGE_SHARED, \
 156                     VM_READ | VM_WRITE | VM_EXEC, 1, NULL, NULL }
 157
 158 #define INIT_THREAD  { \
 159         /* \
 160          * saved main processor registers \
 161          */ \
 162         0, 0, 0, 0, 0, 0, 0, 0, \
 163                        0, 0, 0, \
 164         /* \
 165          * saved cp0 stuff \
 166          */ \
 167         0, \
 168         /* \
 169          * saved fpu/fpu emulator stuff \
 170          */ \
 171         INIT_FPU, \
 172         /* \
 173          * Other stuff associated with the process \
 174          */ \
 175         0, 0, 0, 0, \
 176         /* \
 177          * For now the default is to fix address errors \
 178          */ \
 179         MF_FIXADE, { 0 }, 0, 0 \
 180 }
 181
 182 #ifdef __KERNEL__
 183
 184 #define KERNEL_STACK_SIZE 8192
 185
 186 #if !defined (_LANGUAGE_ASSEMBLY)
 187
 188 /* Free all resources held by a thread. */
 189 #define release_thread(thread) do { } while(0)
 190
 191 extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
 192
 193 /* Copy and release all segment info associated with a VM */
 194 #define copy_segments(p, mm) do { } while(0)
 195 #define release_segments(mm) do { } while(0)
 196
 197 /*
 198  * Return saved PC of a blocked thread.
 199  */
 200 extern inline unsigned long thread_saved_pc(struct thread_struct *t)
 201 {
 202         extern void ret_from_fork(void);
 203
 204         /* New born processes are a special case */
 205         if (t->reg31 == (unsigned long) ret_from_fork)
 206                 return t->reg31;
 207
 208         return ((unsigned long *)t->reg29)[10];
 209 }
 210
 211 /*
 212  * Do necessary setup to start up a newly executed thread.
 213  */
 214 #define start_thread(regs, new_pc, new_sp) do {                         \
 215         /* New thread looses kernel privileges. */                      \
 216         regs->cp0_status = (regs->cp0_status & ~(ST0_CU0|ST0_KSU)) | KU_USER;\
 217         regs->cp0_epc = new_pc;                                         \
 218         regs->regs[29] = new_sp;                                        \
 219         current->thread.current_ds = USER_DS;                           \
 220 } while (0)
 221
 222 unsigned long get_wchan(struct task_struct *p);
 223
 224 #define __PT_REG(reg) ((long)&((struct pt_regs *)0)->reg - sizeof(struct pt_regs))
 225 #define __KSTK_TOS(tsk) ((unsigned long)(tsk) + KERNEL_STACK_SIZE - 32)
 226 #define KSTK_EIP(tsk) (*(unsigned long *)(__KSTK_TOS(tsk) + __PT_REG(cp0_epc)))
 227 #define KSTK_ESP(tsk) (*(unsigned long *)(__KSTK_TOS(tsk) + __PT_REG(regs[29])))
 228
 229 /* Allocation and freeing of basic task resources. */
 230 /*
 231  * NOTE! The task struct and the stack go together
 232  */
 233 #define THREAD_SIZE (2*PAGE_SIZE)
 234 #define alloc_task_struct() \
 235         ((struct task_struct *) __get_free_pages(GFP_KERNEL,1))
 236 #define free_task_struct(p)     free_pages((unsigned long)(p),1)
 237 #define get_task_struct(tsk)      atomic_inc(&virt_to_page(tsk)->count)
 238
 239 #define init_task       (init_task_union.task)
 240 #define init_stack      (init_task_union.stack)
 241
 242 #endif /* !defined (_LANGUAGE_ASSEMBLY) */
 243 #endif /* __KERNEL__ */
 244
 245 /*
 246  * Return_address is a replacement for __builtin_return_address(count)
 247  * which on certain architectures cannot reasonably be implemented in GCC
 248  * (MIPS, Alpha) or is unuseable with -fomit-frame-pointer (i386).
 249  * Note that __builtin_return_address(x>=1) is forbidden because GCC
 250  * aborts compilation on some CPUs.  It's simply not possible to unwind
 251  * some CPU's stackframes.
 252  *
 253  * __builtin_return_address works only for non-leaf functions.  We avoid the
 254  * overhead of a function call by forcing the compiler to save the return
 255  * address register on the stack.
 256  */
 257 #define return_address() ({__asm__ __volatile__("":::"$31");__builtin_return_address(0);})
 258
 259 #endif /* _ASM_PROCESSOR_H */