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 - 2008 Tensilica Inc.
   9 */
  10
  11#ifndef _XTENSA_PROCESSOR_H
  12#define _XTENSA_PROCESSOR_H
  13
  14#include <variant/core.h>
  15#include <platform/hardware.h>
  16
  17#include <linux/compiler.h>
  18#include <asm/ptrace.h>
  19#include <asm/types.h>
  20#include <asm/regs.h>
  21
  22/* Assertions. */
  23
  24#if (XCHAL_HAVE_WINDOWED != 1)
  25# error Linux requires the Xtensa Windowed Registers Option.
  26#endif
  27
  28#define ARCH_SLAB_MINALIGN      XCHAL_DATA_WIDTH
  29
  30/*
  31 * User space process size: 1 GB.
  32 * Windowed call ABI requires caller and callee to be located within the same
  33 * 1 GB region. The C compiler places trampoline code on the stack for sources
  34 * that take the address of a nested C function (a feature used by glibc), so
  35 * the 1 GB requirement applies to the stack as well.
  36 */
  37
  38#ifdef CONFIG_MMU
  39#define TASK_SIZE       __XTENSA_UL_CONST(0x40000000)
  40#else
  41#define TASK_SIZE       (PLATFORM_DEFAULT_MEM_START + PLATFORM_DEFAULT_MEM_SIZE)
  42#endif
  43
  44#define STACK_TOP       TASK_SIZE
  45#define STACK_TOP_MAX   STACK_TOP
  46
  47/*
  48 * General exception cause assigned to debug exceptions. Debug exceptions go
  49 * to their own vector, rather than the general exception vectors (user,
  50 * kernel, double); and their specific causes are reported via DEBUGCAUSE
  51 * rather than EXCCAUSE.  However it is sometimes convenient to redirect debug
  52 * exceptions to the general exception mechanism.  To do this, an otherwise
  53 * unused EXCCAUSE value was assigned to debug exceptions for this purpose.
  54 */
  55
  56#define EXCCAUSE_MAPPED_DEBUG   63
  57
  58/*
  59 * We use DEPC also as a flag to distinguish between double and regular
  60 * exceptions. For performance reasons, DEPC might contain the value of
  61 * EXCCAUSE for regular exceptions, so we use this definition to mark a
  62 * valid double exception address.
  63 * (Note: We use it in bgeui, so it should be 64, 128, or 256)
  64 */
  65
  66#define VALID_DOUBLE_EXCEPTION_ADDRESS  64
  67
  68/* LOCKLEVEL defines the interrupt level that masks all
  69 * general-purpose interrupts.
  70 */
  71#define LOCKLEVEL XCHAL_EXCM_LEVEL
  72
  73/* WSBITS and WBBITS are the width of the WINDOWSTART and WINDOWBASE
  74 * registers
  75 */
  76#define WSBITS  (XCHAL_NUM_AREGS / 4)      /* width of WINDOWSTART in bits */
  77#define WBBITS  (XCHAL_NUM_AREGS_LOG2 - 2) /* width of WINDOWBASE in bits */
  78
  79#ifndef __ASSEMBLY__
  80
  81/* Build a valid return address for the specified call winsize.
  82 * winsize must be 1 (call4), 2 (call8), or 3 (call12)
  83 */
  84#define MAKE_RA_FOR_CALL(ra,ws)   (((ra) & 0x3fffffff) | (ws) << 30)
  85
  86/* Convert return address to a valid pc
  87 * Note: We assume that the stack pointer is in the same 1GB ranges as the ra
  88 */
  89#define MAKE_PC_FROM_RA(ra,sp)    (((ra) & 0x3fffffff) | ((sp) & 0xc0000000))
  90
  91typedef struct {
  92        unsigned long seg;
  93} mm_segment_t;
  94
  95struct thread_struct {
  96
  97        /* kernel's return address and stack pointer for context switching */
  98        unsigned long ra; /* kernel's a0: return address and window call size */
  99        unsigned long sp; /* kernel's a1: stack pointer */
 100
 101        mm_segment_t current_ds;    /* see uaccess.h for example uses */
 102
 103        /* struct xtensa_cpuinfo info; */
 104
 105        unsigned long bad_vaddr; /* last user fault */
 106        unsigned long bad_uaddr; /* last kernel fault accessing user space */
 107        unsigned long error_code;
 108
 109        unsigned long ibreak[XCHAL_NUM_IBREAK];
 110        unsigned long dbreaka[XCHAL_NUM_DBREAK];
 111        unsigned long dbreakc[XCHAL_NUM_DBREAK];
 112
 113        /* Make structure 16 bytes aligned. */
 114        int align[0] __attribute__ ((aligned(16)));
 115};
 116
 117
 118/*
 119 * Default implementation of macro that returns current
 120 * instruction pointer ("program counter").
 121 */
 122#define current_text_addr()  ({ __label__ _l; _l: &&_l;})
 123
 124
 125/* This decides where the kernel will search for a free chunk of vm
 126 * space during mmap's.
 127 */
 128#define TASK_UNMAPPED_BASE      (TASK_SIZE / 2)
 129
 130#define INIT_THREAD  \
 131{                                                                       \
 132        ra:             0,                                              \
 133        sp:             sizeof(init_stack) + (long) &init_stack,        \
 134        current_ds:     {0},                                            \
 135        /*info:         {0}, */                                         \
 136        bad_vaddr:      0,                                              \
 137        bad_uaddr:      0,                                              \
 138        error_code:     0,                                              \
 139}
 140
 141
 142/*
 143 * Do necessary setup to start up a newly executed thread.
 144 * Note: We set-up ps as if we did a call4 to the new pc.
 145 *       set_thread_state in signal.c depends on it.
 146 */
 147#define USER_PS_VALUE ((1 << PS_WOE_BIT) |                              \
 148                       (1 << PS_CALLINC_SHIFT) |                        \
 149                       (USER_RING << PS_RING_SHIFT) |                   \
 150                       (1 << PS_UM_BIT) |                               \
 151                       (1 << PS_EXCM_BIT))
 152
 153/* Clearing a0 terminates the backtrace. */
 154#define start_thread(regs, new_pc, new_sp) \
 155        memset(regs, 0, sizeof(*regs)); \
 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/* Copy and release all segment info associated with a VM */
 173#define copy_segments(p, mm)    do { } while(0)
 174#define release_segments(mm)    do { } while(0)
 175#define forget_segments()       do { } while (0)
 176
 177#define thread_saved_pc(tsk)    (task_pt_regs(tsk)->pc)
 178
 179extern unsigned long get_wchan(struct task_struct *p);
 180
 181#define KSTK_EIP(tsk)           (task_pt_regs(tsk)->pc)
 182#define KSTK_ESP(tsk)           (task_pt_regs(tsk)->areg[1])
 183
 184#define cpu_relax()  barrier()
 185
 186/* Special register access. */
 187
 188#define WSR(v,sr) __asm__ __volatile__ ("wsr %0,"__stringify(sr) :: "a"(v));
 189#define RSR(v,sr) __asm__ __volatile__ ("rsr %0,"__stringify(sr) : "=a"(v));
 190
 191#define set_sr(x,sr) ({unsigned int v=(unsigned int)x; WSR(v,sr);})
 192#define get_sr(sr) ({unsigned int v; RSR(v,sr); v; })
 193
 194#endif  /* __ASSEMBLY__ */
 195#endif  /* _XTENSA_PROCESSOR_H */
 196