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 #ifndef __ASSEMBLY__
  18
  19 #include <asm/ptrace.h>
  20
  21 #ifdef CONFIG_ARC_FPU_SAVE_RESTORE
  22 /* These DPFP regs need to be saved/restored across ctx-sw */
  23 struct arc_fpu {
  24         struct {
  25                 unsigned int l, h;
  26         } aux_dpfp[2];
  27 };
  28 #endif
  29
  30 /* Arch specific stuff which needs to be saved per task.
  31  * However these items are not so important so as to earn a place in
  32  * struct thread_info
  33  */
  34 struct thread_struct {
  35         unsigned long ksp;      /* kernel mode stack pointer */
  36         unsigned long callee_reg;       /* pointer to callee regs */
  37         unsigned long fault_address;    /* dbls as brkpt holder as well */
  38 #ifdef CONFIG_ARC_FPU_SAVE_RESTORE
  39         struct arc_fpu fpu;
  40 #endif
  41 };
  42
  43 #define INIT_THREAD  {                          \
  44         .ksp = sizeof(init_stack) + (unsigned long) init_stack, \
  45 }
  46
  47 /* Forward declaration, a strange C thing */
  48 struct task_struct;
  49
  50 /* Return saved PC of a blocked thread  */
  51 unsigned long thread_saved_pc(struct task_struct *t);
  52
  53 #define task_pt_regs(p) \
  54         ((struct pt_regs *)(THREAD_SIZE + (void *)task_stack_page(p)) - 1)
  55
  56 /* Free all resources held by a thread */
  57 #define release_thread(thread) do { } while (0)
  58
  59 /* Prepare to copy thread state - unlazy all lazy status */
  60 #define prepare_to_copy(tsk)    do { } while (0)
  61
  62 /*
  63  * A lot of busy-wait loops in SMP are based off of non-volatile data otherwise
  64  * get optimised away by gcc
  65  */
  66 #ifdef CONFIG_SMP
  67 #define cpu_relax()     __asm__ __volatile__ ("" : : : "memory")
  68 #else
  69 #define cpu_relax()     do { } while (0)
  70 #endif
  71
  72 #define cpu_relax_lowlatency() cpu_relax()
  73
  74 #define copy_segments(tsk, mm)      do { } while (0)
  75 #define release_segments(mm)        do { } while (0)
  76
  77 #define KSTK_EIP(tsk)   (task_pt_regs(tsk)->ret)
  78
  79 /*
  80  * Where abouts of Task's sp, fp, blink when it was last seen in kernel mode.
  81  * Look in process.c for details of kernel stack layout
  82  */
  83 #define KSTK_ESP(tsk)   (tsk->thread.ksp)
  84
  85 #define KSTK_REG(tsk, off)      (*((unsigned int *)(KSTK_ESP(tsk) + \
  86                                         sizeof(struct callee_regs) + off)))
  87
  88 #define KSTK_BLINK(tsk) KSTK_REG(tsk, 4)
  89 #define KSTK_FP(tsk)    KSTK_REG(tsk, 0)
  90
  91 extern void start_thread(struct pt_regs * regs, unsigned long pc,
  92                          unsigned long usp);
  93
  94 extern unsigned int get_wchan(struct task_struct *p);
  95
  96 /*
  97  * Default implementation of macro that returns current
  98  * instruction pointer ("program counter").
  99  * Should the PC register be read instead ? This macro does not seem to
 100  * be used in many places so this wont be all that bad.
 101  */
 102 #define current_text_addr() ({ __label__ _l; _l: &&_l; })
 103
 104 #endif /* !__ASSEMBLY__ */
 105
 106 /* Kernels Virtual memory area.
 107  * Unlike other architectures(MIPS, sh, cris ) ARC 700 does not have a
 108  * "kernel translated" region (like KSEG2 in MIPS). So we use a upper part
 109  * of the translated bottom 2GB for kernel virtual memory and protect
 110  * these pages from user accesses by disabling Ru, Eu and Wu.
 111  */
 112 #define VMALLOC_SIZE    (0x10000000)    /* 256M */
 113 #define VMALLOC_START   (PAGE_OFFSET - VMALLOC_SIZE)
 114 #define VMALLOC_END     (PAGE_OFFSET)
 115
 116 /* Most of the architectures seem to be keeping some kind of padding between
 117  * userspace TASK_SIZE and PAGE_OFFSET. i.e TASK_SIZE != PAGE_OFFSET.
 118  */
 119 #define USER_KERNEL_GUTTER    0x10000000
 120
 121 /* User address space:
 122  * On ARC700, CPU allows the entire lower half of 32 bit address space to be
 123  * translated. Thus potentially 2G (0:0x7FFF_FFFF) could be User vaddr space.
 124  * However we steal 256M for kernel addr (0x7000_0000:0x7FFF_FFFF) and another
 125  * 256M (0x6000_0000:0x6FFF_FFFF) is gutter between user/kernel spaces
 126  * Thus total User vaddr space is (0:0x5FFF_FFFF)
 127  */
 128 #define TASK_SIZE       (PAGE_OFFSET - VMALLOC_SIZE - USER_KERNEL_GUTTER)
 129
 130 #define STACK_TOP       TASK_SIZE
 131 #define STACK_TOP_MAX   STACK_TOP
 132
 133 /* This decides where the kernel will search for a free chunk of vm
 134  * space during mmap's.
 135  */
 136 #define TASK_UNMAPPED_BASE      (TASK_SIZE / 3)
 137
 138 #endif /* __ASM_ARC_PROCESSOR_H */