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
  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  */
  27 struct 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 */
  45 struct task_struct;
  46
  47 /*
  48  * Return saved PC of a blocked thread.
  49  */
  50 unsigned 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)                          \
  93 do {                                                            \
  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
 105 extern 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 */