1 /*
2 * include/asm-m68knommu/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/compiler.h>
17 #include <linux/threads.h>
18 #include <asm/types.h>
19 #include <asm/segment.h>
20 #include <asm/fpu.h>
21 #include <asm/ptrace.h>
22 #include <asm/current.h>
23
rdusp(void)24 static inline unsigned long rdusp(void)
25 {
26 #ifdef CONFIG_COLDFIRE
27 extern unsigned int sw_usp;
28 return(sw_usp);
29 #else
30 unsigned long usp;
31 __asm__ __volatile__("move %/usp,%0" : "=a" (usp));
32 return usp;
33 #endif
34 }
35
wrusp(unsigned long usp)36 static inline void wrusp(unsigned long usp)
37 {
38 #ifdef CONFIG_COLDFIRE
39 extern unsigned int sw_usp;
40 sw_usp = usp;
41 #else
42 __asm__ __volatile__("move %0,%/usp" : : "a" (usp));
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 #define TASK_SIZE (0xF0000000UL)
51
52 /*
53 * This decides where the kernel will search for a free chunk of vm
54 * space during mmap's. We won't be using it
55 */
56 #define TASK_UNMAPPED_BASE 0
57
58 /*
59 * if you change this structure, you must change the code and offsets
60 * in m68k/machasm.S
61 */
62
63 struct thread_struct {
64 unsigned long ksp; /* kernel stack pointer */
65 unsigned long usp; /* user stack pointer */
66 unsigned short sr; /* saved status register */
67 unsigned short fs; /* saved fs (sfc, dfc) */
68 unsigned long crp[2]; /* cpu root pointer */
69 unsigned long esp0; /* points to SR of stack frame */
70 unsigned long fp[8*3];
71 unsigned long fpcntl[3]; /* fp control regs */
72 unsigned char fpstate[FPSTATESIZE]; /* floating point state */
73 };
74
75 #define INIT_THREAD { \
76 sizeof(init_stack) + (unsigned long) init_stack, 0, \
77 PS_S, __KERNEL_DS, \
78 {0, 0}, 0, {0,}, {0, 0, 0}, {0,}, \
79 }
80
81 /*
82 * Coldfire stacks need to be re-aligned on trap exit, conventional
83 * 68k can handle this case cleanly.
84 */
85 #if defined(CONFIG_COLDFIRE)
86 #define reformat(_regs) do { (_regs)->format = 0x4; } while(0)
87 #else
88 #define reformat(_regs) do { } while (0)
89 #endif
90
91 /*
92 * Do necessary setup to start up a newly executed thread.
93 *
94 * pass the data segment into user programs if it exists,
95 * it can't hurt anything as far as I can tell
96 */
97 #define start_thread(_regs, _pc, _usp) \
98 do { \
99 set_fs(USER_DS); /* reads from user space */ \
100 (_regs)->pc = (_pc); \
101 ((struct switch_stack *)(_regs))[-1].a6 = 0; \
102 reformat(_regs); \
103 if (current->mm) \
104 (_regs)->d5 = current->mm->start_data; \
105 (_regs)->sr &= ~0x2000; \
106 wrusp(_usp); \
107 } while(0)
108
109 /* Forward declaration, a strange C thing */
110 struct task_struct;
111
112 /* Free all resources held by a thread. */
release_thread(struct task_struct * dead_task)113 static inline void release_thread(struct task_struct *dead_task)
114 {
115 }
116
117 /* Prepare to copy thread state - unlazy all lazy status */
118 #define prepare_to_copy(tsk) do { } while (0)
119
120 extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
121
122 /*
123 * Free current thread data structures etc..
124 */
exit_thread(void)125 static inline void exit_thread(void)
126 {
127 }
128
129 unsigned long thread_saved_pc(struct task_struct *tsk);
130 unsigned long get_wchan(struct task_struct *p);
131
132 #define KSTK_EIP(tsk) \
133 ({ \
134 unsigned long eip = 0; \
135 if ((tsk)->thread.esp0 > PAGE_SIZE && \
136 (virt_addr_valid((tsk)->thread.esp0))) \
137 eip = ((struct pt_regs *) (tsk)->thread.esp0)->pc; \
138 eip; })
139 #define KSTK_ESP(tsk) ((tsk) == current ? rdusp() : (tsk)->thread.usp)
140
141 #define cpu_relax() barrier()
142
143 #endif
144