1/*
2 * include/asm-m68k/processor.h
3 *
4 * Copyright (C) 1995 Hamish Macdonald
5 */
6
7#ifndef __ASM_M68K_PROCESSOR_H
8#define __ASM_M68K_PROCESSOR_H
9
10/*
11 * Default implementation of macro that returns current
12 * instruction pointer ("program counter").
13 */
14#define current_text_addr() ({ __label__ _l; _l: &&_l;})
15
16#include <linux/config.h>
17#include <asm/segment.h>
18#include <asm/fpu.h>
19#include <asm/ptrace.h>
20
21extern inline unsigned long rdusp(void) {
22  	unsigned long usp;
23
24	__asm__ __volatile__("move %/usp,%0" : "=a" (usp));
25	return usp;
26}
27
28extern inline void wrusp(unsigned long usp) {
29	__asm__ __volatile__("move %0,%/usp" : : "a" (usp));
30}
31
32/*
33 * User space process size: 3.75GB. This is hardcoded into a few places,
34 * so don't change it unless you know what you are doing.
35 */
36#ifndef CONFIG_SUN3
37#define TASK_SIZE	(0xF0000000UL)
38#else
39#ifdef __ASSEMBLY__
40#define TASK_SIZE	(0x0E000000)
41#else
42#define TASK_SIZE	(0x0E000000UL)
43#endif
44#endif
45
46/* This decides where the kernel will search for a free chunk of vm
47 * space during mmap's.
48 */
49#ifndef CONFIG_SUN3
50#define TASK_UNMAPPED_BASE	0xC0000000UL
51#else
52#define TASK_UNMAPPED_BASE	0x0A000000UL
53#endif
54#define TASK_UNMAPPED_ALIGN(addr, off)	PAGE_ALIGN(addr)
55
56/*
57 * Bus types
58 */
59#define EISA_bus 0
60#define MCA_bus 0
61
62/*
63 * if you change this structure, you must change the code and offsets
64 * in m68k/machasm.S
65 */
66
67struct thread_struct {
68	unsigned long  ksp;		/* kernel stack pointer */
69	unsigned long  usp;		/* user stack pointer */
70	unsigned short sr;		/* saved status register */
71	unsigned short fs;		/* saved fs (sfc, dfc) */
72	unsigned long  crp[2];		/* cpu root pointer */
73	unsigned long  esp0;		/* points to SR of stack frame */
74	unsigned long  faddr;		/* info about last fault */
75	int            signo, code;
76	unsigned long  fp[8*3];
77	unsigned long  fpcntl[3];	/* fp control regs */
78	unsigned char  fpstate[FPSTATESIZE];  /* floating point state */
79};
80
81#define INIT_THREAD  { \
82	sizeof(init_stack) + (unsigned long) init_stack, 0, \
83	PS_S, __KERNEL_DS, \
84}
85
86/*
87 * Do necessary setup to start up a newly executed thread.
88 */
89static inline void start_thread(struct pt_regs * regs, unsigned long pc,
90				unsigned long usp)
91{
92	/* reads from user space */
93	set_fs(USER_DS);
94
95	regs->pc = pc;
96	regs->sr &= ~0x2000;
97	wrusp(usp);
98}
99
100/* Forward declaration, a strange C thing */
101struct task_struct;
102
103/* Free all resources held by a thread. */
104static inline void release_thread(struct task_struct *dead_task)
105{
106}
107
108extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
109
110#define copy_segments(tsk, mm)		do { } while (0)
111#define release_segments(mm)		do { } while (0)
112
113/*
114 * Free current thread data structures etc..
115 */
116static inline void exit_thread(void)
117{
118}
119
120/*
121 * Return saved PC of a blocked thread.
122 */
123extern inline unsigned long thread_saved_pc(struct thread_struct *t)
124{
125	extern void scheduling_functions_start_here(void);
126	extern void scheduling_functions_end_here(void);
127	struct switch_stack *sw = (struct switch_stack *)t->ksp;
128	/* Check whether the thread is blocked in resume() */
129	if (sw->retpc > (unsigned long)scheduling_functions_start_here &&
130	    sw->retpc < (unsigned long)scheduling_functions_end_here)
131		return ((unsigned long *)sw->a6)[1];
132	else
133		return sw->retpc;
134}
135
136unsigned long get_wchan(struct task_struct *p);
137
138#define	KSTK_EIP(tsk)	\
139    ({			\
140	unsigned long eip = 0;	 \
141	if ((tsk)->thread.esp0 > PAGE_SIZE && \
142	    (VALID_PAGE(virt_to_page((tsk)->thread.esp0)))) \
143	      eip = ((struct pt_regs *) (tsk)->thread.esp0)->pc; \
144	eip; })
145#define	KSTK_ESP(tsk)	((tsk) == current ? rdusp() : (tsk)->thread.usp)
146
147#define THREAD_SIZE (2*PAGE_SIZE)
148
149/* Allocation and freeing of basic task resources. */
150#define alloc_task_struct() \
151	((struct task_struct *) __get_free_pages(GFP_KERNEL,1))
152#define free_task_struct(p)	free_pages((unsigned long)(p),1)
153#define get_task_struct(tsk)      atomic_inc(&virt_to_page(tsk)->count)
154
155#define init_task	(init_task_union.task)
156#define init_stack	(init_task_union.stack)
157
158#define cpu_relax()	do { } while (0)
159
160#endif
161