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

   1/*
   2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License version 2 as
   6 * published by the Free Software Foundation.
   7 *
   8 * vineetg: March 2009
   9 *  -Implemented task_pt_regs( )
  10 *
  11 * Amit Bhor, Sameer Dhavale, Ashwin Chaugule: Codito Technologies 2004
  12 */
  13
  14#ifndef __ASM_ARC_PROCESSOR_H
  15#define __ASM_ARC_PROCESSOR_H
  16
  17#ifdef __KERNEL__
  18
  19#ifndef __ASSEMBLY__
  20
  21#include <asm/arcregs.h>        /* for STATUS_E1_MASK et all */
  22#include <asm/ptrace.h>
  23
  24/* Arch specific stuff which needs to be saved per task.
  25 * However these items are not so important so as to earn a place in
  26 * struct thread_info
  27 */
  28struct thread_struct {
  29        unsigned long ksp;      /* kernel mode stack pointer */
  30        unsigned long callee_reg;       /* pointer to callee regs */
  31        unsigned long fault_address;    /* dbls as brkpt holder as well */
  32#ifdef CONFIG_ARC_FPU_SAVE_RESTORE
  33        struct arc_fpu fpu;
  34#endif
  35};
  36
  37#define INIT_THREAD  {                          \
  38        .ksp = sizeof(init_stack) + (unsigned long) init_stack, \
  39}
  40
  41/* Forward declaration, a strange C thing */
  42struct task_struct;
  43
  44/*
  45 * Return saved PC of a blocked thread.
  46 */
  47unsigned long thread_saved_pc(struct task_struct *t);
  48
  49#define task_pt_regs(p) \
  50        ((struct pt_regs *)(THREAD_SIZE + (void *)task_stack_page(p)) - 1)
  51
  52/* Free all resources held by a thread. */
  53#define release_thread(thread) do { } while (0)
  54
  55/* Prepare to copy thread state - unlazy all lazy status */
  56#define prepare_to_copy(tsk)    do { } while (0)
  57
  58/*
  59 * A lot of busy-wait loops in SMP are based off of non-volatile data otherwise
  60 * get optimised away by gcc
  61 */
  62#ifdef CONFIG_SMP
  63#define cpu_relax()     __asm__ __volatile__ ("" : : : "memory")
  64#else
  65#define cpu_relax()     do { } while (0)
  66#endif
  67
  68#define copy_segments(tsk, mm)      do { } while (0)
  69#define release_segments(mm)        do { } while (0)
  70
  71#define KSTK_EIP(tsk)   (task_pt_regs(tsk)->ret)
  72
  73/*
  74 * Where abouts of Task's sp, fp, blink when it was last seen in kernel mode.
  75 * Look in process.c for details of kernel stack layout
  76 */
  77#define KSTK_ESP(tsk)   (tsk->thread.ksp)
  78
  79#define KSTK_REG(tsk, off)      (*((unsigned int *)(KSTK_ESP(tsk) + \
  80                                        sizeof(struct callee_regs) + off)))
  81
  82#define KSTK_BLINK(tsk) KSTK_REG(tsk, 4)
  83#define KSTK_FP(tsk)    KSTK_REG(tsk, 0)
  84
  85/*
  86 * Do necessary setup to start up a newly executed thread.
  87 *
  88 * E1,E2 so that Interrupts are enabled in user mode
  89 * L set, so Loop inhibited to begin with
  90 * lp_start and lp_end seeded with bogus non-zero values so to easily catch
  91 * the ARC700 sr to lp_start hardware bug
  92 */
  93#define start_thread(_regs, _pc, _usp)                          \
  94do {                                                            \
  95        set_fs(USER_DS); /* reads from user space */            \
  96        (_regs)->ret = (_pc);                                   \
  97        /* Interrupts enabled in User Mode */                   \
  98        (_regs)->status32 = STATUS_U_MASK | STATUS_L_MASK       \
  99                | STATUS_E1_MASK | STATUS_E2_MASK;              \
 100        (_regs)->sp = (_usp);                                   \
 101        /* bogus seed values for debugging */                   \
 102        (_regs)->lp_start = 0x10;                               \
 103        (_regs)->lp_end = 0x80;                                 \
 104} while (0)
 105
 106extern unsigned int get_wchan(struct task_struct *p);
 107
 108/*
 109 * Default implementation of macro that returns current
 110 * instruction pointer ("program counter").
 111 * Should the PC register be read instead ? This macro does not seem to
 112 * be used in many places so this wont be all that bad.
 113 */
 114#define current_text_addr() ({ __label__ _l; _l: &&_l; })
 115
 116#endif /* !__ASSEMBLY__ */
 117
 118/* Kernels Virtual memory area.
 119 * Unlike other architectures(MIPS, sh, cris ) ARC 700 does not have a
 120 * "kernel translated" region (like KSEG2 in MIPS). So we use a upper part
 121 * of the translated bottom 2GB for kernel virtual memory and protect
 122 * these pages from user accesses by disabling Ru, Eu and Wu.
 123 */
 124#define VMALLOC_SIZE    (0x10000000)    /* 256M */
 125#define VMALLOC_START   (PAGE_OFFSET - VMALLOC_SIZE)
 126#define VMALLOC_END     (PAGE_OFFSET)
 127
 128/* Most of the architectures seem to be keeping some kind of padding between
 129 * userspace TASK_SIZE and PAGE_OFFSET. i.e TASK_SIZE != PAGE_OFFSET.
 130 */
 131#define USER_KERNEL_GUTTER    0x10000000
 132
 133/* User address space:
 134 * On ARC700, CPU allows the entire lower half of 32 bit address space to be
 135 * translated. Thus potentially 2G (0:0x7FFF_FFFF) could be User vaddr space.
 136 * However we steal 256M for kernel addr (0x7000_0000:0x7FFF_FFFF) and another
 137 * 256M (0x6000_0000:0x6FFF_FFFF) is gutter between user/kernel spaces
 138 * Thus total User vaddr space is (0:0x5FFF_FFFF)
 139 */
 140#define TASK_SIZE       (PAGE_OFFSET - VMALLOC_SIZE - USER_KERNEL_GUTTER)
 141
 142#define STACK_TOP       TASK_SIZE
 143#define STACK_TOP_MAX   STACK_TOP
 144
 145/* This decides where the kernel will search for a free chunk of vm
 146 * space during mmap's.
 147 */
 148#define TASK_UNMAPPED_BASE      (TASK_SIZE / 3)
 149
 150#endif /* __KERNEL__ */
 151
 152#endif /* __ASM_ARC_PROCESSOR_H */
 153