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" */
34 struct task_struct;
35
36 /* this is defined in arch/process.c */
37 extern pid_t kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
38 extern unsigned long thread_saved_pc(struct task_struct *tsk);
39
40 extern 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 */
46 struct 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 */
prepare_to_copy(struct task_struct * tsk)64 static 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 */
91 extern void release_thread(struct task_struct *dead_task);
92
93 /* Get wait channel for task P. */
94 extern 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
110 struct 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