1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
|
/*
* include/asm-m68k/processor.h
*
* Copyright (C) 1995 Hamish Macdonald
*/
#ifndef __ASM_M68K_PROCESSOR_H
#define __ASM_M68K_PROCESSOR_H
#include <asm/segment.h>
#include <asm/fpu.h>
/*
* User space process size: 3.75GB. This is hardcoded into a few places,
* so don't change it unless you know what you are doing.
*/
#define TASK_SIZE (0xF0000000UL)
/* This decides where the kernel will search for a free chunk of vm
* space during mmap's.
*/
#define TASK_UNMAPPED_BASE 0xC0000000UL
/*
* Bus types
*/
#define EISA_bus 0
#define MCA_bus 0
/*
* if you change this structure, you must change the code and offsets
* in m68k/machasm.S
*/
struct thread_struct {
unsigned long ksp; /* kernel stack pointer */
unsigned long usp; /* user stack pointer */
unsigned short sr; /* saved status register */
unsigned short fs; /* saved fs (sfc, dfc) */
unsigned long crp[2]; /* cpu root pointer */
unsigned long esp0; /* points to SR of stack frame */
unsigned long fp[8*3];
unsigned long fpcntl[3]; /* fp control regs */
unsigned char fpstate[FPSTATESIZE]; /* floating point state */
};
#define INIT_MMAP { &init_mm, 0, 0x40000000, __pgprot(_PAGE_PRESENT|_PAGE_ACCESSED), VM_READ | VM_WRITE | VM_EXEC, NULL, &init_mm.mmap }
#define INIT_TSS { \
sizeof(init_stack) + (unsigned long) init_stack, 0, \
PS_S, KERNEL_DS, \
{0, 0}, 0, {0,}, {0, 0, 0}, {0,}, \
}
/*
* Do necessary setup to start up a newly executed thread.
*/
static inline void start_thread(struct pt_regs * regs, unsigned long pc,
unsigned long usp)
{
unsigned long nilstate = 0;
/* clear floating point state */
__asm__ __volatile__ (".chip 68k/68881\n\t"
"frestore %0@\n\t"
".chip 68k" : : "a" (&nilstate));
/* reads from user space */
set_fs(USER_DS);
regs->pc = pc;
regs->sr &= ~0x2000;
wrusp(usp);
}
/* Free all resources held by a thread. */
extern void release_thread(struct task_struct *);
/*
* Return saved PC of a blocked thread.
*/
extern inline unsigned long thread_saved_pc(struct thread_struct *t)
{
extern int sys_pause(void);
extern void schedule(void);
struct switch_stack *sw = (struct switch_stack *)t->ksp;
/* Check whether the thread is blocked in resume() */
if (sw->retpc >= (unsigned long)schedule &&
sw->retpc < (unsigned long)sys_pause)
return ((unsigned long *)sw->a6)[1];
else
return sw->retpc;
}
/* Allocation and freeing of basic task resources. */
#define alloc_task_struct() \
((struct task_struct *) __get_free_pages(GFP_KERNEL,1,0))
#define free_task_struct(p) free_pages((unsigned long)(p),1)
#define init_task (init_task_union.task)
#define init_stack (init_task_union.stack)
/*
* Return_address is a replacement for __builtin_return_address(count)
* which on certain architectures cannot reasonably be implemented in GCC
* (MIPS, Alpha) or is unuseable with -fomit-frame-pointer (i386).
* Note that __builtin_return_address(x>=1) is forbidden because the GCC
* aborts compilation on some CPUs. It's simply not possible to unwind
* some CPU's stackframes.
*/
#define return_address() __builtin_return_address(0)
#endif
|
