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 */
23struct 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 */
34struct 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 */
48struct task_struct;
49
50#define task_pt_regs(p) \
51	((struct pt_regs *)(THREAD_SIZE + (void *)task_stack_page(p)) - 1)
52
53/* Free all resources held by a thread */
54#define release_thread(thread) do { } while (0)
55
56/*
57 * A lot of busy-wait loops in SMP are based off of non-volatile data otherwise
58 * get optimised away by gcc
59 */
60#ifdef CONFIG_SMP
61#define cpu_relax()	__asm__ __volatile__ ("" : : : "memory")
62#else
63#define cpu_relax()	do { } while (0)
64#endif
65
66#define cpu_relax_lowlatency() cpu_relax()
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#define KSTK_ESP(tsk)   (task_pt_regs(tsk)->sp)
73
74/*
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
77 */
78#define TSK_K_ESP(tsk)		(tsk->thread.ksp)
79
80#define TSK_K_REG(tsk, off)	(*((unsigned int *)(TSK_K_ESP(tsk) + \
81					sizeof(struct callee_regs) + off)))
82
83#define TSK_K_BLINK(tsk)	TSK_K_REG(tsk, 4)
84#define TSK_K_FP(tsk)		TSK_K_REG(tsk, 0)
85
86#define thread_saved_pc(tsk)	TSK_K_BLINK(tsk)
87
88extern void start_thread(struct pt_regs * regs, unsigned long pc,
89			 unsigned long usp);
90
91extern unsigned int get_wchan(struct task_struct *p);
92
93/*
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.
98 */
99#define current_text_addr() ({ __label__ _l; _l: &&_l; })
100
101#endif /* !__ASSEMBLY__ */
102
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.
108 */
109#define VMALLOC_SIZE	(0x10000000)	/* 256M */
110#define VMALLOC_START	(PAGE_OFFSET - VMALLOC_SIZE)
111#define VMALLOC_END	(PAGE_OFFSET)
112
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.
115 */
116#define USER_KERNEL_GUTTER    0x10000000
117
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)
124 */
125#define TASK_SIZE	(PAGE_OFFSET - VMALLOC_SIZE - USER_KERNEL_GUTTER)
126
127#define STACK_TOP       TASK_SIZE
128#define STACK_TOP_MAX   STACK_TOP
129
130/* This decides where the kernel will search for a free chunk of vm
131 * space during mmap's.
132 */
133#define TASK_UNMAPPED_BASE      (TASK_SIZE / 3)
134
135#endif /* __ASM_ARC_PROCESSOR_H */
136