1 /*
2  * OpenRISC Linux
3  *
4  * Linux architectural port borrowing liberally from similar works of
5  * others.  All original copyrights apply as per the original source
6  * declaration.
7  *
8  * OpenRISC implementation:
9  * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
10  * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
11  * et al.
12  *
13  * This program is free software; you can redistribute it and/or modify
14  * it under the terms of the GNU General Public License as published by
15  * the Free Software Foundation; either version 2 of the License, or
16  * (at your option) any later version.
17  */
18 
19 #ifndef __ASM_OPENRISC_PROCESSOR_H
20 #define __ASM_OPENRISC_PROCESSOR_H
21 
22 #include <asm/spr_defs.h>
23 #include <asm/page.h>
24 #include <asm/ptrace.h>
25 
26 #define STACK_TOP       TASK_SIZE
27 #define STACK_TOP_MAX	STACK_TOP
28 /* Kernel and user SR register setting */
29 #define KERNEL_SR (SPR_SR_DME | SPR_SR_IME | SPR_SR_ICE \
30 		   | SPR_SR_DCE | SPR_SR_SM)
31 #define USER_SR   (SPR_SR_DME | SPR_SR_IME | SPR_SR_ICE \
32 		   | SPR_SR_DCE | SPR_SR_IEE | SPR_SR_TEE)
33 /*
34  * Default implementation of macro that returns current
35  * instruction pointer ("program counter").
36  */
37 #define current_text_addr() ({ __label__ _l; _l: &&_l; })
38 
39 /*
40  * User space process size. This is hardcoded into a few places,
41  * so don't change it unless you know what you are doing.
42  */
43 
44 #define TASK_SIZE       (0x80000000UL)
45 
46 /* This decides where the kernel will search for a free chunk of vm
47  * space during mmap's.
48  */
49 #define TASK_UNMAPPED_BASE      (TASK_SIZE / 8 * 3)
50 
51 #ifndef __ASSEMBLY__
52 
53 struct task_struct;
54 
55 struct thread_struct {
56 };
57 
58 /*
59  * At user->kernel entry, the pt_regs struct is stacked on the top of the
60  * kernel-stack.  This macro allows us to find those regs for a task.
61  * Notice that subsequent pt_regs stackings, like recursive interrupts
62  * occurring while we're in the kernel, won't affect this - only the first
63  * user->kernel transition registers are reached by this (i.e. not regs
64  * for running signal handler)
65  */
66 #define user_regs(thread_info)  (((struct pt_regs *)((unsigned long)(thread_info) + THREAD_SIZE - STACK_FRAME_OVERHEAD)) - 1)
67 
68 /*
69  * Dito but for the currently running task
70  */
71 
72 #define task_pt_regs(task) user_regs(task_thread_info(task))
73 
74 #define INIT_SP         (sizeof(init_stack) + (unsigned long) &init_stack)
75 
76 #define INIT_THREAD  { }
77 
78 
79 #define KSTK_EIP(tsk)   (task_pt_regs(tsk)->pc)
80 #define KSTK_ESP(tsk)   (task_pt_regs(tsk)->sp)
81 
82 
83 void start_thread(struct pt_regs *regs, unsigned long nip, unsigned long sp);
84 void release_thread(struct task_struct *);
85 unsigned long get_wchan(struct task_struct *p);
86 
87 /*
88  * Free current thread data structures etc..
89  */
90 
91 extern inline void exit_thread(void)
92 {
93 	/* Nothing needs to be done.  */
94 }
95 
96 /*
97  * Return saved PC of a blocked thread. For now, this is the "user" PC
98  */
99 extern unsigned long thread_saved_pc(struct task_struct *t);
100 
101 #define init_stack      (init_thread_union.stack)
102 
103 #define cpu_relax()     barrier()
104 
105 #endif /* __ASSEMBLY__ */
106 #endif /* __ASM_OPENRISC_PROCESSOR_H */
107