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" */
34 struct task_struct;
35 
36 extern void start_thread(struct pt_regs *, unsigned long, unsigned long);
37 
38 /*
39  * thread_struct is supposed to be for context switch data.
40  * Specifically, to hold the state necessary to perform switch_to...
41  */
42 struct thread_struct {
43 	void *switch_sp;
44 };
45 
46 /*
47  * initializes thread_struct
48  * The only thing we have in there is switch_sp
49  * which doesn't really need to be initialized.
50  */
51 
52 #define INIT_THREAD { \
53 }
54 
55 #define cpu_relax() __vmyield()
56 
57 /*
58  * Decides where the kernel will search for a free chunk of vm space during
59  * mmaps.
60  * See also arch_get_unmapped_area.
61  * Doesn't affect if you have MAX_FIXED in the page flags set though...
62  *
63  * Apparently the convention is that ld.so will ask for "unmapped" private
64  * memory to be allocated SOMEWHERE, but it also asks for memory explicitly
65  * via MAP_FIXED at the lower * addresses starting at VA=0x0.
66  *
67  * If the two requests collide, you get authentic segfaulting action, so
68  * you have to kick the "unmapped" base requests higher up.
69  */
70 #define TASK_UNMAPPED_BASE	(PAGE_ALIGN(TASK_SIZE/3))
71 
72 
73 #define task_pt_regs(task) \
74 	((struct pt_regs *)(task_stack_page(task) + THREAD_SIZE) - 1)
75 
76 #define KSTK_EIP(tsk) (pt_elr(task_pt_regs(tsk)))
77 #define KSTK_ESP(tsk) (pt_psp(task_pt_regs(tsk)))
78 
79 /*  Free all resources held by a thread; defined in process.c  */
80 extern void release_thread(struct task_struct *dead_task);
81 
82 /* Get wait channel for task P.  */
83 extern unsigned long get_wchan(struct task_struct *p);
84 
85 /*  The following stuff is pretty HEXAGON specific.  */
86 
87 /*  This is really just here for __switch_to.
88     Offsets are pulled via asm-offsets.c  */
89 
90 /*
91  * No real reason why VM and native switch stacks should be different.
92  * Ultimately this should merge.  Note that Rev C. ABI called out only
93  * R24-27 as callee saved GPRs needing explicit attention (R29-31 being
94  * dealt with automagically by allocframe), but the current ABI has
95  * more, R16-R27.  By saving more, the worst case is that we waste some
96  * cycles if building with the old compilers.
97  */
98 
99 struct hexagon_switch_stack {
100 	union {
101 		struct {
102 			unsigned long r16;
103 			unsigned long r17;
104 		};
105 		unsigned long long	r1716;
106 	};
107 	union {
108 		struct {
109 			unsigned long r18;
110 			unsigned long r19;
111 		};
112 		unsigned long long	r1918;
113 	};
114 	union {
115 		struct {
116 			unsigned long r20;
117 			unsigned long r21;
118 		};
119 		unsigned long long	r2120;
120 	};
121 	union {
122 		struct {
123 			unsigned long r22;
124 			unsigned long r23;
125 		};
126 		unsigned long long	r2322;
127 	};
128 	union {
129 		struct {
130 			unsigned long r24;
131 			unsigned long r25;
132 		};
133 		unsigned long long	r2524;
134 	};
135 	union {
136 		struct {
137 			unsigned long r26;
138 			unsigned long r27;
139 		};
140 		unsigned long long	r2726;
141 	};
142 
143 	unsigned long		fp;
144 	unsigned long		lr;
145 };
146 
147 #endif /* !__ASSEMBLY__ */
148 
149 #endif
150