1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License.  See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 1994 Waldorf GMBH
7 * Copyright (C) 1995, 1996, 1997, 1998, 1999, 2001 Ralf Baechle
8 * Copyright (C) 1996 Paul M. Antoine
9 * Copyright (C) 1999 Silicon Graphics, Inc.
10 */
11#ifndef _ASM_PROCESSOR_H
12#define _ASM_PROCESSOR_H
13
14#include <linux/config.h>
15#include <linux/cache.h>
16#include <asm/isadep.h>
17
18/*
19 * Default implementation of macro that returns current
20 * instruction pointer ("program counter").
21 */
22#define current_text_addr() ({ __label__ _l; _l: &&_l;})
23
24#ifndef __ASSEMBLY__
25#include <linux/threads.h>
26#include <asm/cachectl.h>
27#include <asm/mipsregs.h>
28#include <asm/reg.h>
29#include <asm/system.h>
30
31struct cpuinfo_mips {
32	unsigned long udelay_val;
33	unsigned long *pgd_quick;
34	unsigned long *pte_quick;
35	unsigned long pgtable_cache_sz;
36	unsigned long asid_cache;
37} __attribute__((__aligned__(SMP_CACHE_BYTES)));
38
39/*
40 * System setup and hardware flags..
41 */
42extern void (*cpu_wait)(void);
43
44extern struct cpuinfo_mips cpu_data[];
45extern unsigned int vced_count, vcei_count;
46
47#ifdef CONFIG_SMP
48#define current_cpu_data cpu_data[smp_processor_id()]
49#else
50#define current_cpu_data cpu_data[0]
51#endif
52
53/*
54 * Bus types (default is ISA, but people can check others with these..)
55 */
56#ifdef CONFIG_EISA
57extern int EISA_bus;
58#else
59#define EISA_bus (0)
60#endif
61
62#define MCA_bus 0
63#define MCA_bus__is_a_macro /* for versions in ksyms.c */
64
65/*
66 * MIPS has no problems with write protection
67 */
68#define wp_works_ok 1
69#define wp_works_ok__is_a_macro /* for versions in ksyms.c */
70
71/*
72 * User space process size: 2GB. This is hardcoded into a few places,
73 * so don't change it unless you know what you are doing.  TASK_SIZE
74 * for a 64 bit kernel expandable to 8192EB, of which the current MIPS
75 * implementations will "only" be able to use 1TB ...
76 */
77#define TASK_SIZE	(0x7fff8000UL)
78
79/* This decides where the kernel will search for a free chunk of vm
80 * space during mmap's.
81 */
82#define TASK_UNMAPPED_BASE	(TASK_SIZE / 3)
83
84/*
85 * Size of io_bitmap in longwords: 32 is ports 0-0x3ff.
86 */
87#define IO_BITMAP_SIZE	32
88
89#define NUM_FPU_REGS	32
90
91struct mips_fpu_hard_struct {
92	double fp_regs[NUM_FPU_REGS];
93	unsigned int control;
94};
95
96/*
97 * It would be nice to add some more fields for emulator statistics, but there
98 * are a number of fixed offsets in offset.h and elsewhere that would have to
99 * be recalculated by hand.  So the additional information will be private to
100 * the FPU emulator for now.  See asm-mips/fpu_emulator.h.
101 */
102typedef u64 fpureg_t;
103struct mips_fpu_soft_struct {
104	fpureg_t	regs[NUM_FPU_REGS];
105	unsigned int	sr;
106};
107
108union mips_fpu_union {
109        struct mips_fpu_hard_struct hard;
110        struct mips_fpu_soft_struct soft;
111};
112
113#define INIT_FPU { \
114	{{0,},} \
115}
116
117typedef struct {
118	unsigned long seg;
119} mm_segment_t;
120
121/*
122 * If you change thread_struct remember to change the #defines below too!
123 */
124struct thread_struct {
125	/* Saved main processor registers. */
126	unsigned long reg16;
127	unsigned long reg17, reg18, reg19, reg20, reg21, reg22, reg23;
128	unsigned long reg29, reg30, reg31;
129
130	/* Saved cp0 stuff. */
131	unsigned long cp0_status;
132
133	/* Saved fpu/fpu emulator stuff. */
134	union mips_fpu_union fpu;
135
136	/* Other stuff associated with the thread. */
137	unsigned long cp0_badvaddr;	/* Last user fault */
138	unsigned long cp0_baduaddr;	/* Last kernel fault accessing USEG */
139	unsigned long error_code;
140	unsigned long trap_no;
141#define MF_FIXADE 1			/* Fix address errors in software */
142#define MF_LOGADE 2			/* Log address errors to syslog */
143	unsigned long mflags;
144	mm_segment_t current_ds;
145	unsigned long irix_trampoline;  /* Wheee... */
146	unsigned long irix_oldctx;
147};
148
149#endif /* !__ASSEMBLY__ */
150
151#define INIT_THREAD  { \
152        /* \
153         * saved main processor registers \
154         */ \
155	0, 0, 0, 0, 0, 0, 0, 0, \
156	               0, 0, 0, \
157	/* \
158	 * saved cp0 stuff \
159	 */ \
160	0, \
161	/* \
162	 * saved fpu/fpu emulator stuff \
163	 */ \
164	INIT_FPU, \
165	/* \
166	 * Other stuff associated with the process \
167	 */ \
168	0, 0, 0, 0, \
169	/* \
170	 * For now the default is to fix address errors \
171	 */ \
172	MF_FIXADE, { 0 }, 0, 0 \
173}
174
175#ifdef __KERNEL__
176
177#define KERNEL_STACK_SIZE 8192
178
179#ifndef __ASSEMBLY__
180
181/* Free all resources held by a thread. */
182#define release_thread(thread) do { } while(0)
183
184extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
185
186/* Copy and release all segment info associated with a VM */
187#define copy_segments(p, mm) do { } while(0)
188#define release_segments(mm) do { } while(0)
189
190/*
191 * Return saved PC of a blocked thread.
192 */
193static inline unsigned long thread_saved_pc(struct thread_struct *t)
194{
195	extern void ret_from_fork(void);
196
197	/* New born processes are a special case */
198	if (t->reg31 == (unsigned long) ret_from_fork)
199		return t->reg31;
200
201	return ((unsigned long *)t->reg29)[13];
202}
203
204/*
205 * Do necessary setup to start up a newly executed thread.
206 */
207extern void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp);
208
209struct task_struct;
210unsigned long get_wchan(struct task_struct *p);
211
212#define __PT_REG(reg) ((long)&((struct pt_regs *)0)->reg - sizeof(struct pt_regs))
213#define __KSTK_TOS(tsk) ((unsigned long)(tsk) + KERNEL_STACK_SIZE - 32)
214#define KSTK_EIP(tsk) (*(unsigned long *)(__KSTK_TOS(tsk) + __PT_REG(cp0_epc)))
215#define KSTK_ESP(tsk) (*(unsigned long *)(__KSTK_TOS(tsk) + __PT_REG(regs[29])))
216#define KSTK_STATUS(tsk) (*(unsigned long *)(__KSTK_TOS(tsk) + __PT_REG(cp0_status)))
217
218/* Allocation and freeing of basic task resources. */
219/*
220 * NOTE! The task struct and the stack go together
221 */
222#define THREAD_SIZE (2*PAGE_SIZE)
223#define alloc_task_struct() \
224	((struct task_struct *) __get_free_pages(GFP_KERNEL,1))
225#define free_task_struct(p)	free_pages((unsigned long)(p),1)
226#define get_task_struct(tsk)      atomic_inc(&virt_to_page(tsk)->count)
227
228#define init_task	(init_task_union.task)
229#define init_stack	(init_task_union.stack)
230
231#define cpu_relax()	do { } while (0)
232
233#endif /* !__ASSEMBLY__ */
234#endif /* __KERNEL__ */
235
236/*
237 * Return_address is a replacement for __builtin_return_address(count)
238 * which on certain architectures cannot reasonably be implemented in GCC
239 * (MIPS, Alpha) or is unuseable with -fomit-frame-pointer (i386).
240 * Note that __builtin_return_address(x>=1) is forbidden because GCC
241 * aborts compilation on some CPUs.  It's simply not possible to unwind
242 * some CPU's stackframes.
243 *
244 * __builtin_return_address works only for non-leaf functions.  We avoid the
245 * overhead of a function call by forcing the compiler to save the return
246 * address register on the stack.
247 */
248#define return_address() ({__asm__ __volatile__("":::"$31");__builtin_return_address(0);})
249
250#endif /* _ASM_PROCESSOR_H */
251