Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * Process/processor support for the Hexagon architecture
3 *
4 * Copyright (c) 2010-2012, The Linux Foundation. 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/* task_struct, defined elsewhere, is the "process descriptor" */
31struct task_struct;
32
33extern void start_thread(struct pt_regs *, unsigned long, unsigned long);
34
35/*
36 * thread_struct is supposed to be for context switch data.
37 * Specifically, to hold the state necessary to perform switch_to...
38 */
39struct thread_struct {
40 void *switch_sp;
41};
42
43/*
44 * initializes thread_struct
45 * The only thing we have in there is switch_sp
46 * which doesn't really need to be initialized.
47 */
48
49#define INIT_THREAD { \
50}
51
52#define cpu_relax() __vmyield()
53
54/*
55 * Decides where the kernel will search for a free chunk of vm space during
56 * mmaps.
57 * See also arch_get_unmapped_area.
58 * Doesn't affect if you have MAX_FIXED in the page flags set though...
59 *
60 * Apparently the convention is that ld.so will ask for "unmapped" private
61 * memory to be allocated SOMEWHERE, but it also asks for memory explicitly
62 * via MAP_FIXED at the lower * addresses starting at VA=0x0.
63 *
64 * If the two requests collide, you get authentic segfaulting action, so
65 * you have to kick the "unmapped" base requests higher up.
66 */
67#define TASK_UNMAPPED_BASE (PAGE_ALIGN(TASK_SIZE/3))
68
69
70#define task_pt_regs(task) \
71 ((struct pt_regs *)(task_stack_page(task) + THREAD_SIZE) - 1)
72
73#define KSTK_EIP(tsk) (pt_elr(task_pt_regs(tsk)))
74#define KSTK_ESP(tsk) (pt_psp(task_pt_regs(tsk)))
75
76/* Free all resources held by a thread; defined in process.c */
77extern void release_thread(struct task_struct *dead_task);
78
79/* Get wait channel for task P. */
80extern unsigned long get_wchan(struct task_struct *p);
81
82/* The following stuff is pretty HEXAGON specific. */
83
84/* This is really just here for __switch_to.
85 Offsets are pulled via asm-offsets.c */
86
87/*
88 * No real reason why VM and native switch stacks should be different.
89 * Ultimately this should merge. Note that Rev C. ABI called out only
90 * R24-27 as callee saved GPRs needing explicit attention (R29-31 being
91 * dealt with automagically by allocframe), but the current ABI has
92 * more, R16-R27. By saving more, the worst case is that we waste some
93 * cycles if building with the old compilers.
94 */
95
96struct hexagon_switch_stack {
97 union {
98 struct {
99 unsigned long r16;
100 unsigned long r17;
101 };
102 unsigned long long r1716;
103 };
104 union {
105 struct {
106 unsigned long r18;
107 unsigned long r19;
108 };
109 unsigned long long r1918;
110 };
111 union {
112 struct {
113 unsigned long r20;
114 unsigned long r21;
115 };
116 unsigned long long r2120;
117 };
118 union {
119 struct {
120 unsigned long r22;
121 unsigned long r23;
122 };
123 unsigned long long r2322;
124 };
125 union {
126 struct {
127 unsigned long r24;
128 unsigned long r25;
129 };
130 unsigned long long r2524;
131 };
132 union {
133 struct {
134 unsigned long r26;
135 unsigned long r27;
136 };
137 unsigned long long r2726;
138 };
139
140 unsigned long fp;
141 unsigned long lr;
142};
143
144#endif /* !__ASSEMBLY__ */
145
146#endif