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/*  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#define cpu_relax_lowlatency() cpu_relax()
60
61/*
62 * Decides where the kernel will search for a free chunk of vm space during
63 * mmaps.
64 * See also arch_get_unmapped_area.
65 * Doesn't affect if you have MAX_FIXED in the page flags set though...
66 *
67 * Apparently the convention is that ld.so will ask for "unmapped" private
68 * memory to be allocated SOMEWHERE, but it also asks for memory explicitly
69 * via MAP_FIXED at the lower * addresses starting at VA=0x0.
70 *
71 * If the two requests collide, you get authentic segfaulting action, so
72 * you have to kick the "unmapped" base requests higher up.
73 */
74#define TASK_UNMAPPED_BASE	(PAGE_ALIGN(TASK_SIZE/3))
75
76
77#define task_pt_regs(task) \
78	((struct pt_regs *)(task_stack_page(task) + THREAD_SIZE) - 1)
79
80#define KSTK_EIP(tsk) (pt_elr(task_pt_regs(tsk)))
81#define KSTK_ESP(tsk) (pt_psp(task_pt_regs(tsk)))
82
83/*  Free all resources held by a thread; defined in process.c  */
84extern void release_thread(struct task_struct *dead_task);
85
86/* Get wait channel for task P.  */
87extern unsigned long get_wchan(struct task_struct *p);
88
89/*  The following stuff is pretty HEXAGON specific.  */
90
91/*  This is really just here for __switch_to.
92    Offsets are pulled via asm-offsets.c  */
93
94/*
95 * No real reason why VM and native switch stacks should be different.
96 * Ultimately this should merge.  Note that Rev C. ABI called out only
97 * R24-27 as callee saved GPRs needing explicit attention (R29-31 being
98 * dealt with automagically by allocframe), but the current ABI has
99 * more, R16-R27.  By saving more, the worst case is that we waste some
100 * cycles if building with the old compilers.
101 */
102
103struct hexagon_switch_stack {
104	union {
105		struct {
106			unsigned long r16;
107			unsigned long r17;
108		};
109		unsigned long long	r1716;
110	};
111	union {
112		struct {
113			unsigned long r18;
114			unsigned long r19;
115		};
116		unsigned long long	r1918;
117	};
118	union {
119		struct {
120			unsigned long r20;
121			unsigned long r21;
122		};
123		unsigned long long	r2120;
124	};
125	union {
126		struct {
127			unsigned long r22;
128			unsigned long r23;
129		};
130		unsigned long long	r2322;
131	};
132	union {
133		struct {
134			unsigned long r24;
135			unsigned long r25;
136		};
137		unsigned long long	r2524;
138	};
139	union {
140		struct {
141			unsigned long r26;
142			unsigned long r27;
143		};
144		unsigned long long	r2726;
145	};
146
147	unsigned long		fp;
148	unsigned long		lr;
149};
150
151#endif /* !__ASSEMBLY__ */
152
153#endif
154