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
19 #include <asm/ptrace.h>
21 #ifdef CONFIG_ARC_FPU_SAVE_RESTORE
22 /* These DPFP regs need to be saved/restored across ctx-sw */
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
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
43 #define INIT_THREAD { \
44 .ksp = sizeof(init_stack) + (unsigned long) init_stack, \
47 /* Forward declaration, a strange C thing */
50 #define task_pt_regs(p) \
51 ((struct pt_regs *)(THREAD_SIZE + (void *)task_stack_page(p)) - 1)
53 /* Free all resources held by a thread */
54 #define release_thread(thread) do { } while (0)
57 * A lot of busy-wait loops in SMP are based off of non-volatile data otherwise
58 * get optimised away by gcc
61 #define cpu_relax() __asm__ __volatile__ ("" : : : "memory")
63 #define cpu_relax() do { } while (0)
66 #define cpu_relax_lowlatency() cpu_relax()
68 #define copy_segments(tsk, mm) do { } while (0)
69 #define release_segments(mm) do { } while (0)
71 #define KSTK_EIP(tsk) (task_pt_regs(tsk)->ret)
72 #define KSTK_ESP(tsk) (task_pt_regs(tsk)->sp)
75 * Where abouts of Task's sp, fp, blink when it was last seen in kernel mode.
76 * Look in process.c for details of kernel stack layout
78 #define TSK_K_ESP(tsk) (tsk->thread.ksp)
80 #define TSK_K_REG(tsk, off) (*((unsigned int *)(TSK_K_ESP(tsk) + \
81 sizeof(struct callee_regs) + off)))
83 #define TSK_K_BLINK(tsk) TSK_K_REG(tsk, 4)
84 #define TSK_K_FP(tsk) TSK_K_REG(tsk, 0)
86 #define thread_saved_pc(tsk) TSK_K_BLINK(tsk)
88 extern void start_thread(struct pt_regs * regs, unsigned long pc,
91 extern unsigned int get_wchan(struct task_struct *p);
94 * Default implementation of macro that returns current
95 * instruction pointer ("program counter").
96 * Should the PC register be read instead ? This macro does not seem to
97 * be used in many places so this wont be all that bad.
99 #define current_text_addr() ({ __label__ _l; _l: &&_l; })
101 #endif /* !__ASSEMBLY__ */
103 /* Kernels Virtual memory area.
104 * Unlike other architectures(MIPS, sh, cris ) ARC 700 does not have a
105 * "kernel translated" region (like KSEG2 in MIPS). So we use a upper part
106 * of the translated bottom 2GB for kernel virtual memory and protect
107 * these pages from user accesses by disabling Ru, Eu and Wu.
109 #define VMALLOC_SIZE (0x10000000) /* 256M */
110 #define VMALLOC_START (PAGE_OFFSET - VMALLOC_SIZE)
111 #define VMALLOC_END (PAGE_OFFSET)
113 /* Most of the architectures seem to be keeping some kind of padding between
114 * userspace TASK_SIZE and PAGE_OFFSET. i.e TASK_SIZE != PAGE_OFFSET.
116 #define USER_KERNEL_GUTTER 0x10000000
118 /* User address space:
119 * On ARC700, CPU allows the entire lower half of 32 bit address space to be
120 * translated. Thus potentially 2G (0:0x7FFF_FFFF) could be User vaddr space.
121 * However we steal 256M for kernel addr (0x7000_0000:0x7FFF_FFFF) and another
122 * 256M (0x6000_0000:0x6FFF_FFFF) is gutter between user/kernel spaces
123 * Thus total User vaddr space is (0:0x5FFF_FFFF)
125 #define TASK_SIZE (PAGE_OFFSET - VMALLOC_SIZE - USER_KERNEL_GUTTER)
127 #define STACK_TOP TASK_SIZE
128 #define STACK_TOP_MAX STACK_TOP
130 /* This decides where the kernel will search for a free chunk of vm
131 * space during mmap's.
133 #define TASK_UNMAPPED_BASE (TASK_SIZE / 3)
135 #endif /* __ASM_ARC_PROCESSOR_H */