1/*
2 * Process/processor support for the Hexagon architecture
3 *
4 * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 and
8 * only version 2 as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
18 * 02110-1301, USA.
19 */
20
21#ifndef _ASM_PROCESSOR_H
22#define _ASM_PROCESSOR_H
23
24#ifndef __ASSEMBLY__
25
26#include <asm/mem-layout.h>
27#include <asm/registers.h>
28#include <asm/hexagon_vm.h>
29
30/*  must be a macro  */
31#define current_text_addr() ({ __label__ _l; _l: &&_l; })
32
33/*  task_struct, defined elsewhere, is the "process descriptor" */
34struct task_struct;
35
36/*  this is defined in arch/process.c  */
37extern pid_t kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
38extern unsigned long thread_saved_pc(struct task_struct *tsk);
39
40extern void start_thread(struct pt_regs *, unsigned long, unsigned long);
41
42/*
43 * thread_struct is supposed to be for context switch data.
44 * Specifically, to hold the state necessary to perform switch_to...
45 */
46struct thread_struct {
47	void *switch_sp;
48};
49
50/*
51 * initializes thread_struct
52 * The only thing we have in there is switch_sp
53 * which doesn't really need to be initialized.
54 */
55
56#define INIT_THREAD { \
57}
58
59#define cpu_relax() __vmyield()
60
61/*
62 * "Unlazying all lazy status" occurs here.
63 */
64static inline void prepare_to_copy(struct task_struct *tsk)
65{
66}
67
68/*
69 * Decides where the kernel will search for a free chunk of vm space during
70 * mmaps.
71 * See also arch_get_unmapped_area.
72 * Doesn't affect if you have MAX_FIXED in the page flags set though...
73 *
74 * Apparently the convention is that ld.so will ask for "unmapped" private
75 * memory to be allocated SOMEWHERE, but it also asks for memory explicitly
76 * via MAP_FIXED at the lower * addresses starting at VA=0x0.
77 *
78 * If the two requests collide, you get authentic segfaulting action, so
79 * you have to kick the "unmapped" base requests higher up.
80 */
81#define TASK_UNMAPPED_BASE	(PAGE_ALIGN(TASK_SIZE/3))
82
83
84#define task_pt_regs(task) \
85	((struct pt_regs *)(task_stack_page(task) + THREAD_SIZE) - 1)
86
87#define KSTK_EIP(tsk) (pt_elr(task_pt_regs(tsk)))
88#define KSTK_ESP(tsk) (pt_psp(task_pt_regs(tsk)))
89
90/*  Free all resources held by a thread; defined in process.c  */
91extern void release_thread(struct task_struct *dead_task);
92
93/* Get wait channel for task P.  */
94extern unsigned long get_wchan(struct task_struct *p);
95
96/*  The following stuff is pretty HEXAGON specific.  */
97
98/*  This is really just here for __switch_to.
99    Offsets are pulled via asm-offsets.c  */
100
101/*
102 * No real reason why VM and native switch stacks should be different.
103 * Ultimately this should merge.  Note that Rev C. ABI called out only
104 * R24-27 as callee saved GPRs needing explicit attention (R29-31 being
105 * dealt with automagically by allocframe), but the current ABI has
106 * more, R16-R27.  By saving more, the worst case is that we waste some
107 * cycles if building with the old compilers.
108 */
109
110struct hexagon_switch_stack {
111	unsigned long long	r1716;
112	unsigned long long	r1918;
113	unsigned long long	r2120;
114	unsigned long long	r2322;
115	unsigned long long	r2524;
116	unsigned long long	r2726;
117	unsigned long		fp;
118	unsigned long		lr;
119};
120
121#endif /* !__ASSEMBLY__ */
122
123#endif
124