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#ifdef CONFIG_COLDFIRE_SW_A7
24	extern unsigned int sw_usp;
25	return sw_usp;
26#else
27	register unsigned long usp __asm__("a0");
28	/* move %usp,%a0 */
29	__asm__ __volatile__(".word 0x4e68" : "=a" (usp));
30	return usp;
31#endif
32}
33
34static inline void wrusp(unsigned long usp)
35{
36#ifdef CONFIG_COLDFIRE_SW_A7
37	extern unsigned int sw_usp;
38	sw_usp = usp;
39#else
40	register unsigned long a0 __asm__("a0") = usp;
41	/* move %a0,%usp */
42	__asm__ __volatile__(".word 0x4e60" : : "a" (a0) );
43#endif
44}
45
46/*
47 * User space process size: 3.75GB. This is hardcoded into a few places,
48 * so don't change it unless you know what you are doing.
49 */
50#ifdef CONFIG_MMU
51#if defined(CONFIG_COLDFIRE)
52#define TASK_SIZE	(0xC0000000UL)
53#elif defined(CONFIG_SUN3)
54#define TASK_SIZE	(0x0E000000UL)
55#else
56#define TASK_SIZE	(0xF0000000UL)
57#endif
58#else
59#define TASK_SIZE	(0xFFFFFFFFUL)
60#endif
61
62#ifdef __KERNEL__
63#define STACK_TOP	TASK_SIZE
64#define STACK_TOP_MAX	STACK_TOP
65#endif
66
67/* This decides where the kernel will search for a free chunk of vm
68 * space during mmap's.
69 */
70#ifdef CONFIG_MMU
71#if defined(CONFIG_COLDFIRE)
72#define TASK_UNMAPPED_BASE	0x60000000UL
73#elif defined(CONFIG_SUN3)
74#define TASK_UNMAPPED_BASE	0x0A000000UL
75#else
76#define TASK_UNMAPPED_BASE	0xC0000000UL
77#endif
78#define TASK_UNMAPPED_ALIGN(addr, off)	PAGE_ALIGN(addr)
79#else
80#define TASK_UNMAPPED_BASE	0
81#endif
82
83struct thread_struct {
84	unsigned long  ksp;		/* kernel stack pointer */
85	unsigned long  usp;		/* user stack pointer */
86	unsigned short sr;		/* saved status register */
87	unsigned short fs;		/* saved fs (sfc, dfc) */
88	unsigned long  crp[2];		/* cpu root pointer */
89	unsigned long  esp0;		/* points to SR of stack frame */
90	unsigned long  faddr;		/* info about last fault */
91	int            signo, code;
92	unsigned long  fp[8*3];
93	unsigned long  fpcntl[3];	/* fp control regs */
94	unsigned char  fpstate[FPSTATESIZE];  /* floating point state */
95};
96
97#define INIT_THREAD  {							\
98	.ksp	= sizeof(init_stack) + (unsigned long) init_stack,	\
99	.sr	= PS_S,							\
100	.fs	= __KERNEL_DS,						\
101}
102
103/*
104 * ColdFire stack format sbould be 0x4 for an aligned usp (will always be
105 * true on thread creation). We need to set this explicitly.
106 */
107#ifdef CONFIG_COLDFIRE
108#define setframeformat(_regs)	do { (_regs)->format = 0x4; } while(0)
109#else
110#define setframeformat(_regs)	do { } while (0)
111#endif
112
113#ifdef CONFIG_MMU
114/*
115 * Do necessary setup to start up a newly executed thread.
116 */
117static inline void start_thread(struct pt_regs * regs, unsigned long pc,
118				unsigned long usp)
119{
120	regs->pc = pc;
121	regs->sr &= ~0x2000;
122	setframeformat(regs);
123	wrusp(usp);
124}
125
126extern int handle_kernel_fault(struct pt_regs *regs);
127
128#else
129
130#define start_thread(_regs, _pc, _usp)                  \
131do {                                                    \
132	(_regs)->pc = (_pc);                            \
133	setframeformat(_regs);                          \
134	if (current->mm)                                \
135		(_regs)->d5 = current->mm->start_data;  \
136	(_regs)->sr &= ~0x2000;                         \
137	wrusp(_usp);                                    \
138} while(0)
139
140static inline  int handle_kernel_fault(struct pt_regs *regs)
141{
142	/* Any fault in kernel is fatal on non-mmu */
143	return 0;
144}
145
146#endif
147
148/* Forward declaration, a strange C thing */
149struct task_struct;
150
151/* Free all resources held by a thread. */
152static inline void release_thread(struct task_struct *dead_task)
153{
154}
155
156/*
157 * Free current thread data structures etc..
158 */
159static inline void exit_thread(void)
160{
161}
162
163extern unsigned long thread_saved_pc(struct task_struct *tsk);
164
165unsigned long get_wchan(struct task_struct *p);
166
167#define	KSTK_EIP(tsk)	\
168    ({			\
169	unsigned long eip = 0;	 \
170	if ((tsk)->thread.esp0 > PAGE_SIZE && \
171	    (virt_addr_valid((tsk)->thread.esp0))) \
172	      eip = ((struct pt_regs *) (tsk)->thread.esp0)->pc; \
173	eip; })
174#define	KSTK_ESP(tsk)	((tsk) == current ? rdusp() : (tsk)->thread.usp)
175
176#define task_pt_regs(tsk)	((struct pt_regs *) ((tsk)->thread.esp0))
177
178#define cpu_relax()	barrier()
179#define cpu_relax_lowlatency() cpu_relax()
180
181#endif
182