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/thread_info.h>
17#include <asm/segment.h>
18#include <asm/fpu.h>
19#include <asm/ptrace.h>
20
21static inline unsigned long rdusp(void)
22{
23	unsigned long usp;
24
25	__asm__ __volatile__("move %/usp,%0" : "=a" (usp));
26	return usp;
27}
28
29static inline void wrusp(unsigned long usp)
30{
31	__asm__ __volatile__("move %0,%/usp" : : "a" (usp));
32}
33
34/*
35 * User space process size: 3.75GB. This is hardcoded into a few places,
36 * so don't change it unless you know what you are doing.
37 */
38#ifndef CONFIG_SUN3
39#define TASK_SIZE	(0xF0000000UL)
40#else
41#ifdef __ASSEMBLY__
42#define TASK_SIZE	(0x0E000000)
43#else
44#define TASK_SIZE	(0x0E000000UL)
45#endif
46#endif
47
48/* This decides where the kernel will search for a free chunk of vm
49 * space during mmap's.
50 */
51#ifndef CONFIG_SUN3
52#define TASK_UNMAPPED_BASE	0xC0000000UL
53#else
54#define TASK_UNMAPPED_BASE	0x0A000000UL
55#endif
56#define TASK_UNMAPPED_ALIGN(addr, off)	PAGE_ALIGN(addr)
57
58struct thread_struct {
59	unsigned long  ksp;		/* kernel stack pointer */
60	unsigned long  usp;		/* user stack pointer */
61	unsigned short sr;		/* saved status register */
62	unsigned short fs;		/* saved fs (sfc, dfc) */
63	unsigned long  crp[2];		/* cpu root pointer */
64	unsigned long  esp0;		/* points to SR of stack frame */
65	unsigned long  faddr;		/* info about last fault */
66	int            signo, code;
67	unsigned long  fp[8*3];
68	unsigned long  fpcntl[3];	/* fp control regs */
69	unsigned char  fpstate[FPSTATESIZE];  /* floating point state */
70	struct thread_info info;
71};
72
73#define INIT_THREAD  {							\
74	.ksp	= sizeof(init_stack) + (unsigned long) init_stack,	\
75	.sr	= PS_S,							\
76	.fs	= __KERNEL_DS,						\
77	.info	= INIT_THREAD_INFO(init_task),				\
78}
79
80/*
81 * Do necessary setup to start up a newly executed thread.
82 */
83static inline void start_thread(struct pt_regs * regs, unsigned long pc,
84				unsigned long usp)
85{
86	/* reads from user space */
87	set_fs(USER_DS);
88
89	regs->pc = pc;
90	regs->sr &= ~0x2000;
91	wrusp(usp);
92}
93
94/* Forward declaration, a strange C thing */
95struct task_struct;
96
97/* Free all resources held by a thread. */
98static inline void release_thread(struct task_struct *dead_task)
99{
100}
101
102/* Prepare to copy thread state - unlazy all lazy status */
103#define prepare_to_copy(tsk)	do { } while (0)
104
105extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
106
107/*
108 * Free current thread data structures etc..
109 */
110static inline void exit_thread(void)
111{
112}
113
114extern unsigned long thread_saved_pc(struct task_struct *tsk);
115
116unsigned long get_wchan(struct task_struct *p);
117
118#define	KSTK_EIP(tsk)	\
119    ({			\
120	unsigned long eip = 0;	 \
121	if ((tsk)->thread.esp0 > PAGE_SIZE && \
122	    (virt_addr_valid((tsk)->thread.esp0))) \
123	      eip = ((struct pt_regs *) (tsk)->thread.esp0)->pc; \
124	eip; })
125#define	KSTK_ESP(tsk)	((tsk) == current ? rdusp() : (tsk)->thread.usp)
126
127#define cpu_relax()	barrier()
128
129#endif
130