linux/arch/arc/include/asm/processor.h
<<
>>
Prefs
   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
  23/* Arch specific stuff which needs to be saved per task.
  24 * However these items are not so important so as to earn a place in
  25 * struct thread_info
  26 */
  27struct thread_struct {
  28        unsigned long ksp;      /* kernel mode stack pointer */
  29        unsigned long callee_reg;       /* pointer to callee regs */
  30        unsigned long fault_address;    /* dbls as brkpt holder as well */
  31        unsigned long cause_code;       /* Exception Cause Code (ECR) */
  32#ifdef CONFIG_ARC_CURR_IN_REG
  33        unsigned long user_r25;
  34#endif
  35#ifdef CONFIG_ARC_FPU_SAVE_RESTORE
  36        struct arc_fpu fpu;
  37#endif
  38};
  39
  40#define INIT_THREAD  {                          \
  41        .ksp = sizeof(init_stack) + (unsigned long) init_stack, \
  42}
  43
  44/* Forward declaration, a strange C thing */
  45struct task_struct;
  46
  47/*
  48 * Return saved PC of a blocked thread.
  49 */
  50unsigned long thread_saved_pc(struct task_struct *t);
  51
  52#define task_pt_regs(p) \
  53        ((struct pt_regs *)(THREAD_SIZE - 4 + (void *)task_stack_page(p)) - 1)
  54
  55/* Free all resources held by a thread. */
  56#define release_thread(thread) do { } while (0)
  57
  58/* Prepare to copy thread state - unlazy all lazy status */
  59#define prepare_to_copy(tsk)    do { } while (0)
  60
  61/*
  62 * A lot of busy-wait loops in SMP are based off of non-volatile data otherwise
  63 * get optimised away by gcc
  64 */
  65#ifdef CONFIG_SMP
  66#define cpu_relax()     __asm__ __volatile__ ("" : : : "memory")
  67#else
  68#define cpu_relax()     do { } while (0)
  69#endif
  70
  71#define copy_segments(tsk, mm)      do { } while (0)
  72#define release_segments(mm)        do { } while (0)
  73
  74#define KSTK_EIP(tsk)   (task_pt_regs(tsk)->ret)
  75
  76/*
  77 * Where abouts of Task's sp, fp, blink when it was last seen in kernel mode.
  78 * These can't be derived from pt_regs as that would give correp user-mode val
  79 */
  80#define KSTK_ESP(tsk)   (tsk->thread.ksp)
  81#define KSTK_BLINK(tsk) (*((unsigned int *)((KSTK_ESP(tsk)) + (13+1+1)*4)))
  82#define KSTK_FP(tsk)    (*((unsigned int *)((KSTK_ESP(tsk)) + (13+1)*4)))
  83
  84/*
  85 * Do necessary setup to start up a newly executed thread.
  86 *
  87 * E1,E2 so that Interrupts are enabled in user mode
  88 * L set, so Loop inhibited to begin with
  89 * lp_start and lp_end seeded with bogus non-zero values so to easily catch
  90 * the ARC700 sr to lp_start hardware bug
  91 */
  92#define start_thread(_regs, _pc, _usp)                          \
  93do {                                                            \
  94        set_fs(USER_DS); /* reads from user space */            \
  95        (_regs)->ret = (_pc);                                   \
  96        /* Interrupts enabled in User Mode */                   \
  97        (_regs)->status32 = STATUS_U_MASK | STATUS_L_MASK       \
  98                | STATUS_E1_MASK | STATUS_E2_MASK;              \
  99        (_regs)->sp = (_usp);                                   \
 100        /* bogus seed values for debugging */                   \
 101        (_regs)->lp_start = 0x10;                               \
 102        (_regs)->lp_end = 0x80;                                 \
 103} while (0)
 104
 105extern unsigned int get_wchan(struct task_struct *p);
 106
 107/*
 108 * Default implementation of macro that returns current
 109 * instruction pointer ("program counter").
 110 * Should the PC register be read instead ? This macro does not seem to
 111 * be used in many places so this wont be all that bad.
 112 */
 113#define current_text_addr() ({ __label__ _l; _l: &&_l; })
 114
 115#endif /* !__ASSEMBLY__ */
 116
 117/* Kernels Virtual memory area.
 118 * Unlike other architectures(MIPS, sh, cris ) ARC 700 does not have a
 119 * "kernel translated" region (like KSEG2 in MIPS). So we use a upper part
 120 * of the translated bottom 2GB for kernel virtual memory and protect
 121 * these pages from user accesses by disabling Ru, Eu and Wu.
 122 */
 123#define VMALLOC_SIZE    (0x10000000)    /* 256M */
 124#define VMALLOC_START   (PAGE_OFFSET - VMALLOC_SIZE)
 125#define VMALLOC_END     (PAGE_OFFSET)
 126
 127/* Most of the architectures seem to be keeping some kind of padding between
 128 * userspace TASK_SIZE and PAGE_OFFSET. i.e TASK_SIZE != PAGE_OFFSET.
 129 */
 130#define USER_KERNEL_GUTTER    0x10000000
 131
 132/* User address space:
 133 * On ARC700, CPU allows the entire lower half of 32 bit address space to be
 134 * translated. Thus potentially 2G (0:0x7FFF_FFFF) could be User vaddr space.
 135 * However we steal 256M for kernel addr (0x7000_0000:0x7FFF_FFFF) and another
 136 * 256M (0x6000_0000:0x6FFF_FFFF) is gutter between user/kernel spaces
 137 * Thus total User vaddr space is (0:0x5FFF_FFFF)
 138 */
 139#define TASK_SIZE       (PAGE_OFFSET - VMALLOC_SIZE - USER_KERNEL_GUTTER)
 140
 141#define STACK_TOP       TASK_SIZE
 142#define STACK_TOP_MAX   STACK_TOP
 143
 144/* This decides where the kernel will search for a free chunk of vm
 145 * space during mmap's.
 146 */
 147#define TASK_UNMAPPED_BASE      (TASK_SIZE / 3)
 148
 149#endif /* __KERNEL__ */
 150
 151#endif /* __ASM_ARC_PROCESSOR_H */
 152