LXR linux/arch/xtensa/include/asm/processor.h

   1/*
   2 * include/asm-xtensa/processor.h
   3 *
   4 * This file is subject to the terms and conditions of the GNU General Public
   5 * License.  See the file "COPYING" in the main directory of this archive
   6 * for more details.
   7 *
   8 * Copyright (C) 2001 - 2005 Tensilica Inc.
   9 */
  10
  11#ifndef _XTENSA_PROCESSOR_H
  12#define _XTENSA_PROCESSOR_H
  13
  14#include <variant/core.h>
  15#include <asm/coprocessor.h>
  16#include <platform/hardware.h>
  17
  18#include <linux/compiler.h>
  19#include <asm/ptrace.h>
  20#include <asm/types.h>
  21#include <asm/regs.h>
  22
  23/* Assertions. */
  24
  25#if (XCHAL_HAVE_WINDOWED != 1)
  26# error Linux requires the Xtensa Windowed Registers Option.
  27#endif
  28
  29#define ARCH_SLAB_MINALIGN      XCHAL_DATA_WIDTH
  30
  31/*
  32 * User space process size: 1 GB.
  33 * Windowed call ABI requires caller and callee to be located within the same
  34 * 1 GB region. The C compiler places trampoline code on the stack for sources
  35 * that take the address of a nested C function (a feature used by glibc), so
  36 * the 1 GB requirement applies to the stack as well.
  37 */
  38
  39#ifdef CONFIG_MMU
  40#define TASK_SIZE       __XTENSA_UL_CONST(0x40000000)
  41#else
  42#define TASK_SIZE       (PLATFORM_DEFAULT_MEM_START + PLATFORM_DEFAULT_MEM_SIZE)
  43#endif
  44
  45#define STACK_TOP       TASK_SIZE
  46#define STACK_TOP_MAX   STACK_TOP
  47
  48/*
  49 * General exception cause assigned to debug exceptions. Debug exceptions go
  50 * to their own vector, rather than the general exception vectors (user,
  51 * kernel, double); and their specific causes are reported via DEBUGCAUSE
  52 * rather than EXCCAUSE.  However it is sometimes convenient to redirect debug
  53 * exceptions to the general exception mechanism.  To do this, an otherwise
  54 * unused EXCCAUSE value was assigned to debug exceptions for this purpose.
  55 */
  56
  57#define EXCCAUSE_MAPPED_DEBUG   63
  58
  59/*
  60 * We use DEPC also as a flag to distinguish between double and regular
  61 * exceptions. For performance reasons, DEPC might contain the value of
  62 * EXCCAUSE for regular exceptions, so we use this definition to mark a
  63 * valid double exception address.
  64 * (Note: We use it in bgeui, so it should be 64, 128, or 256)
  65 */
  66
  67#define VALID_DOUBLE_EXCEPTION_ADDRESS  64
  68
  69/* LOCKLEVEL defines the interrupt level that masks all
  70 * general-purpose interrupts.
  71 */
  72#define LOCKLEVEL 1
  73
  74/* WSBITS and WBBITS are the width of the WINDOWSTART and WINDOWBASE
  75 * registers
  76 */
  77#define WSBITS  (XCHAL_NUM_AREGS / 4)      /* width of WINDOWSTART in bits */
  78#define WBBITS  (XCHAL_NUM_AREGS_LOG2 - 2) /* width of WINDOWBASE in bits */
  79
  80#ifndef __ASSEMBLY__
  81
  82/* Build a valid return address for the specified call winsize.
  83 * winsize must be 1 (call4), 2 (call8), or 3 (call12)
  84 */
  85#define MAKE_RA_FOR_CALL(ra,ws)   (((ra) & 0x3fffffff) | (ws) << 30)
  86
  87/* Convert return address to a valid pc
  88 * Note: We assume that the stack pointer is in the same 1GB ranges as the ra
  89 */
  90#define MAKE_PC_FROM_RA(ra,sp)    (((ra) & 0x3fffffff) | ((sp) & 0xc0000000))
  91
  92typedef struct {
  93    unsigned long seg;
  94} mm_segment_t;
  95
  96struct thread_struct {
  97
  98        /* kernel's return address and stack pointer for context switching */
  99        unsigned long ra; /* kernel's a0: return address and window call size */
 100        unsigned long sp; /* kernel's a1: stack pointer */
 101
 102        mm_segment_t current_ds;    /* see uaccess.h for example uses */
 103
 104        /* struct xtensa_cpuinfo info; */
 105
 106        unsigned long bad_vaddr; /* last user fault */
 107        unsigned long bad_uaddr; /* last kernel fault accessing user space */
 108        unsigned long error_code;
 109
 110        unsigned long ibreak[XCHAL_NUM_IBREAK];
 111        unsigned long dbreaka[XCHAL_NUM_DBREAK];
 112        unsigned long dbreakc[XCHAL_NUM_DBREAK];
 113
 114        /* Make structure 16 bytes aligned. */
 115        int align[0] __attribute__ ((aligned(16)));
 116};
 117
 118
 119/*
 120 * Default implementation of macro that returns current
 121 * instruction pointer ("program counter").
 122 */
 123#define current_text_addr()  ({ __label__ _l; _l: &&_l;})
 124
 125
 126/* This decides where the kernel will search for a free chunk of vm
 127 * space during mmap's.
 128 */
 129#define TASK_UNMAPPED_BASE      (TASK_SIZE / 2)
 130
 131#define INIT_THREAD  \
 132{                                                                       \
 133        ra:             0,                                              \
 134        sp:             sizeof(init_stack) + (long) &init_stack,        \
 135        current_ds:     {0},                                            \
 136        /*info:         {0}, */                                         \
 137        bad_vaddr:      0,                                              \
 138        bad_uaddr:      0,                                              \
 139        error_code:     0,                                              \
 140}
 141
 142
 143/*
 144 * Do necessary setup to start up a newly executed thread.
 145 * Note: We set-up ps as if we did a call4 to the new pc.
 146 *       set_thread_state in signal.c depends on it.
 147 */
 148#define USER_PS_VALUE ((1 << PS_WOE_BIT) |                              \
 149                       (1 << PS_CALLINC_SHIFT) |                        \
 150                       (USER_RING << PS_RING_SHIFT) |                   \
 151                       (1 << PS_UM_BIT) |                               \
 152                       (1 << PS_EXCM_BIT))
 153
 154/* Clearing a0 terminates the backtrace. */
 155#define start_thread(regs, new_pc, new_sp) \
 156        regs->pc = new_pc; \
 157        regs->ps = USER_PS_VALUE; \
 158        regs->areg[1] = new_sp; \
 159        regs->areg[0] = 0; \
 160        regs->wmask = 1; \
 161        regs->depc = 0; \
 162        regs->windowbase = 0; \
 163        regs->windowstart = 1;
 164
 165/* Forward declaration */
 166struct task_struct;
 167struct mm_struct;
 168
 169/* Free all resources held by a thread. */
 170#define release_thread(thread) do { } while(0)
 171
 172/* Prepare to copy thread state - unlazy all lazy status */
 173extern void prepare_to_copy(struct task_struct*);
 174
 175/* Create a kernel thread without removing it from tasklists */
 176extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
 177
 178/* Copy and release all segment info associated with a VM */
 179#define copy_segments(p, mm)    do { } while(0)
 180#define release_segments(mm)    do { } while(0)
 181#define forget_segments()       do { } while (0)
 182
 183#define thread_saved_pc(tsk)    (task_pt_regs(tsk)->pc)
 184
 185extern unsigned long get_wchan(struct task_struct *p);
 186
 187#define KSTK_EIP(tsk)           (task_pt_regs(tsk)->pc)
 188#define KSTK_ESP(tsk)           (task_pt_regs(tsk)->areg[1])
 189
 190#define cpu_relax()  barrier()
 191
 192/* Special register access. */
 193
 194#define WSR(v,sr) __asm__ __volatile__ ("wsr %0,"__stringify(sr) :: "a"(v));
 195#define RSR(v,sr) __asm__ __volatile__ ("rsr %0,"__stringify(sr) : "=a"(v));
 196
 197#define set_sr(x,sr) ({unsigned int v=(unsigned int)x; WSR(v,sr);})
 198#define get_sr(sr) ({unsigned int v; RSR(v,sr); v; })
 199
 200#endif  /* __ASSEMBLY__ */
 201#endif  /* _XTENSA_PROCESSOR_H */
 202