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  */
  28 struct 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 */
  42 struct task_struct;
  43
  44 /*
  45  * Return saved PC of a blocked thread.
  46  */
  47 unsigned 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)                          \
  94 do {                                                            \
  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
 106 extern 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 */