aboutsummaryrefslogtreecommitdiff
path: root/arch/arc/include/asm/processor.h
blob: 5f26b2c1cba0074f68123061efb8441061df1f96 (plain)
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
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
/*
 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * vineetg: March 2009
 *  -Implemented task_pt_regs( )
 *
 * Amit Bhor, Sameer Dhavale, Ashwin Chaugule: Codito Technologies 2004
 */

#ifndef __ASM_ARC_PROCESSOR_H
#define __ASM_ARC_PROCESSOR_H

#ifdef __KERNEL__

#ifndef __ASSEMBLY__

#include <asm/arcregs.h>	/* for STATUS_E1_MASK et all */

/* Arch specific stuff which needs to be saved per task.
 * However these items are not so important so as to earn a place in
 * struct thread_info
 */
struct thread_struct {
	unsigned long ksp;	/* kernel mode stack pointer */
	unsigned long callee_reg;	/* pointer to callee regs */
	unsigned long fault_address;	/* dbls as brkpt holder as well */
	unsigned long cause_code;	/* Exception Cause Code (ECR) */
#ifdef CONFIG_ARC_CURR_IN_REG
	unsigned long user_r25;
#endif
#ifdef CONFIG_ARC_FPU_SAVE_RESTORE
	struct arc_fpu fpu;
#endif
};

#define INIT_THREAD  {                          \
	.ksp = sizeof(init_stack) + (unsigned long) init_stack, \
}

/* Forward declaration, a strange C thing */
struct task_struct;

/*
 * Return saved PC of a blocked thread.
 */
unsigned long thread_saved_pc(struct task_struct *t);

#define task_pt_regs(p) \
	((struct pt_regs *)(THREAD_SIZE - 4 + (void *)task_stack_page(p)) - 1)

/* Free all resources held by a thread. */
#define release_thread(thread) do { } while (0)

/* Prepare to copy thread state - unlazy all lazy status */
#define prepare_to_copy(tsk)    do { } while (0)

/*
 * A lot of busy-wait loops in SMP are based off of non-volatile data otherwise
 * get optimised away by gcc
 */
#ifdef CONFIG_SMP
#define cpu_relax()	__asm__ __volatile__ ("" : : : "memory")
#else
#define cpu_relax()	do { } while (0)
#endif

#define copy_segments(tsk, mm)      do { } while (0)
#define release_segments(mm)        do { } while (0)

#define KSTK_EIP(tsk)   (task_pt_regs(tsk)->ret)

/*
 * Where abouts of Task's sp, fp, blink when it was last seen in kernel mode.
 * These can't be derived from pt_regs as that would give correp user-mode val
 */
#define KSTK_ESP(tsk)   (tsk->thread.ksp)
#define KSTK_BLINK(tsk) (*((unsigned int *)((KSTK_ESP(tsk)) + (13+1+1)*4)))
#define KSTK_FP(tsk)    (*((unsigned int *)((KSTK_ESP(tsk)) + (13+1)*4)))

/*
 * Do necessary setup to start up a newly executed thread.
 *
 * E1,E2 so that Interrupts are enabled in user mode
 * L set, so Loop inhibited to begin with
 * lp_start and lp_end seeded with bogus non-zero values so to easily catch
 * the ARC700 sr to lp_start hardware bug
 */
#define start_thread(_regs, _pc, _usp)				\
do {								\
	set_fs(USER_DS); /* reads from user space */		\
	(_regs)->ret = (_pc);					\
	/* Interrupts enabled in User Mode */			\
	(_regs)->status32 = STATUS_U_MASK | STATUS_L_MASK	\
		| STATUS_E1_MASK | STATUS_E2_MASK;		\
	(_regs)->sp = (_usp);					\
	/* bogus seed values for debugging */			\
	(_regs)->lp_start = 0x10;				\
	(_regs)->lp_end = 0x80;					\
} while (0)

extern unsigned int get_wchan(struct task_struct *p);

/*
 * Default implementation of macro that returns current
 * instruction pointer ("program counter").
 * Should the PC register be read instead ? This macro does not seem to
 * be used in many places so this wont be all that bad.
 */
#define current_text_addr() ({ __label__ _l; _l: &&_l; })

#endif /* !__ASSEMBLY__ */

/* Kernels Virtual memory area.
 * Unlike other architectures(MIPS, sh, cris ) ARC 700 does not have a
 * "kernel translated" region (like KSEG2 in MIPS). So we use a upper part
 * of the translated bottom 2GB for kernel virtual memory and protect
 * these pages from user accesses by disabling Ru, Eu and Wu.
 */
#define VMALLOC_SIZE	(0x10000000)	/* 256M */
#define VMALLOC_START	(PAGE_OFFSET - VMALLOC_SIZE)
#define VMALLOC_END	(PAGE_OFFSET)

/* Most of the architectures seem to be keeping some kind of padding between
 * userspace TASK_SIZE and PAGE_OFFSET. i.e TASK_SIZE != PAGE_OFFSET.
 */
#define USER_KERNEL_GUTTER    0x10000000

/* User address space:
 * On ARC700, CPU allows the entire lower half of 32 bit address space to be
 * translated. Thus potentially 2G (0:0x7FFF_FFFF) could be User vaddr space.
 * However we steal 256M for kernel addr (0x7000_0000:0x7FFF_FFFF) and another
 * 256M (0x6000_0000:0x6FFF_FFFF) is gutter between user/kernel spaces
 * Thus total User vaddr space is (0:0x5FFF_FFFF)
 */
#define TASK_SIZE	(PAGE_OFFSET - VMALLOC_SIZE - USER_KERNEL_GUTTER)

#define STACK_TOP       TASK_SIZE
#define STACK_TOP_MAX   STACK_TOP

/* This decides where the kernel will search for a free chunk of vm
 * space during mmap's.
 */
#define TASK_UNMAPPED_BASE      (TASK_SIZE / 3)

#endif /* __KERNEL__ */

#endif /* __ASM_ARC_PROCESSOR_H */