2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
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.
9 * -Implemented task_pt_regs( )
11 * Amit Bhor, Sameer Dhavale, Ashwin Chaugule: Codito Technologies 2004
14 #ifndef __ASM_ARC_PROCESSOR_H
15 #define __ASM_ARC_PROCESSOR_H
21 #include <asm/ptrace.h>
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
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 #ifdef CONFIG_ARC_FPU_SAVE_RESTORE
36 #define INIT_THREAD { \
37 .ksp = sizeof(init_stack) + (unsigned long) init_stack, \
40 /* Forward declaration, a strange C thing */
43 /* Return saved PC of a blocked thread */
44 unsigned long thread_saved_pc(struct task_struct *t);
46 #define task_pt_regs(p) \
47 ((struct pt_regs *)(THREAD_SIZE + (void *)task_stack_page(p)) - 1)
49 /* Free all resources held by a thread */
50 #define release_thread(thread) do { } while (0)
52 /* Prepare to copy thread state - unlazy all lazy status */
53 #define prepare_to_copy(tsk) do { } while (0)
56 * A lot of busy-wait loops in SMP are based off of non-volatile data otherwise
57 * get optimised away by gcc
60 #define cpu_relax() __asm__ __volatile__ ("" : : : "memory")
62 #define cpu_relax() do { } while (0)
65 #define copy_segments(tsk, mm) do { } while (0)
66 #define release_segments(mm) do { } while (0)
68 #define KSTK_EIP(tsk) (task_pt_regs(tsk)->ret)
71 * Where abouts of Task's sp, fp, blink when it was last seen in kernel mode.
72 * Look in process.c for details of kernel stack layout
74 #define KSTK_ESP(tsk) (tsk->thread.ksp)
76 #define KSTK_REG(tsk, off) (*((unsigned int *)(KSTK_ESP(tsk) + \
77 sizeof(struct callee_regs) + off)))
79 #define KSTK_BLINK(tsk) KSTK_REG(tsk, 4)
80 #define KSTK_FP(tsk) KSTK_REG(tsk, 0)
82 extern void start_thread(struct pt_regs * regs, unsigned long pc,
85 extern unsigned int get_wchan(struct task_struct *p);
88 * Default implementation of macro that returns current
89 * instruction pointer ("program counter").
90 * Should the PC register be read instead ? This macro does not seem to
91 * be used in many places so this wont be all that bad.
93 #define current_text_addr() ({ __label__ _l; _l: &&_l; })
95 #endif /* !__ASSEMBLY__ */
97 /* Kernels Virtual memory area.
98 * Unlike other architectures(MIPS, sh, cris ) ARC 700 does not have a
99 * "kernel translated" region (like KSEG2 in MIPS). So we use a upper part
100 * of the translated bottom 2GB for kernel virtual memory and protect
101 * these pages from user accesses by disabling Ru, Eu and Wu.
103 #define VMALLOC_SIZE (0x10000000) /* 256M */
104 #define VMALLOC_START (PAGE_OFFSET - VMALLOC_SIZE)
105 #define VMALLOC_END (PAGE_OFFSET)
107 /* Most of the architectures seem to be keeping some kind of padding between
108 * userspace TASK_SIZE and PAGE_OFFSET. i.e TASK_SIZE != PAGE_OFFSET.
110 #define USER_KERNEL_GUTTER 0x10000000
112 /* User address space:
113 * On ARC700, CPU allows the entire lower half of 32 bit address space to be
114 * translated. Thus potentially 2G (0:0x7FFF_FFFF) could be User vaddr space.
115 * However we steal 256M for kernel addr (0x7000_0000:0x7FFF_FFFF) and another
116 * 256M (0x6000_0000:0x6FFF_FFFF) is gutter between user/kernel spaces
117 * Thus total User vaddr space is (0:0x5FFF_FFFF)
119 #define TASK_SIZE (PAGE_OFFSET - VMALLOC_SIZE - USER_KERNEL_GUTTER)
121 #define STACK_TOP TASK_SIZE
122 #define STACK_TOP_MAX STACK_TOP
124 /* This decides where the kernel will search for a free chunk of vm
125 * space during mmap's.
127 #define TASK_UNMAPPED_BASE (TASK_SIZE / 3)
129 #endif /* __KERNEL__ */
131 #endif /* __ASM_ARC_PROCESSOR_H */