Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1/*
2 * Process/processor support for the Hexagon architecture
3 *
4 * Copyright (c) 2010-2011, 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/* 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 unsigned long thread_saved_pc(struct task_struct *tsk);
38
39extern void start_thread(struct pt_regs *, unsigned long, unsigned long);
40
41/*
42 * thread_struct is supposed to be for context switch data.
43 * Specifically, to hold the state necessary to perform switch_to...
44 */
45struct thread_struct {
46 void *switch_sp;
47};
48
49/*
50 * initializes thread_struct
51 * The only thing we have in there is switch_sp
52 * which doesn't really need to be initialized.
53 */
54
55#define INIT_THREAD { \
56}
57
58#define cpu_relax() __vmyield()
59
60/*
61 * Decides where the kernel will search for a free chunk of vm space during
62 * mmaps.
63 * See also arch_get_unmapped_area.
64 * Doesn't affect if you have MAX_FIXED in the page flags set though...
65 *
66 * Apparently the convention is that ld.so will ask for "unmapped" private
67 * memory to be allocated SOMEWHERE, but it also asks for memory explicitly
68 * via MAP_FIXED at the lower * addresses starting at VA=0x0.
69 *
70 * If the two requests collide, you get authentic segfaulting action, so
71 * you have to kick the "unmapped" base requests higher up.
72 */
73#define TASK_UNMAPPED_BASE (PAGE_ALIGN(TASK_SIZE/3))
74
75
76#define task_pt_regs(task) \
77 ((struct pt_regs *)(task_stack_page(task) + THREAD_SIZE) - 1)
78
79#define KSTK_EIP(tsk) (pt_elr(task_pt_regs(tsk)))
80#define KSTK_ESP(tsk) (pt_psp(task_pt_regs(tsk)))
81
82/* Free all resources held by a thread; defined in process.c */
83extern void release_thread(struct task_struct *dead_task);
84
85/* Get wait channel for task P. */
86extern unsigned long get_wchan(struct task_struct *p);
87
88/* The following stuff is pretty HEXAGON specific. */
89
90/* This is really just here for __switch_to.
91 Offsets are pulled via asm-offsets.c */
92
93/*
94 * No real reason why VM and native switch stacks should be different.
95 * Ultimately this should merge. Note that Rev C. ABI called out only
96 * R24-27 as callee saved GPRs needing explicit attention (R29-31 being
97 * dealt with automagically by allocframe), but the current ABI has
98 * more, R16-R27. By saving more, the worst case is that we waste some
99 * cycles if building with the old compilers.
100 */
101
102struct hexagon_switch_stack {
103 unsigned long long r1716;
104 unsigned long long r1918;
105 unsigned long long r2120;
106 unsigned long long r2322;
107 unsigned long long r2524;
108 unsigned long long r2726;
109 unsigned long fp;
110 unsigned long lr;
111};
112
113#endif /* !__ASSEMBLY__ */
114
115#endif