1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Process/processor support for the Hexagon architecture
4  *
5  * Copyright (c) 2010-2012, The Linux Foundation. All rights reserved.
6  */
7 
8 #ifndef _ASM_PROCESSOR_H
9 #define _ASM_PROCESSOR_H
10 
11 #ifndef __ASSEMBLY__
12 
13 #include <asm/mem-layout.h>
14 #include <asm/registers.h>
15 #include <asm/hexagon_vm.h>
16 
17 /*  task_struct, defined elsewhere, is the "process descriptor" */
18 struct task_struct;
19 
20 extern void start_thread(struct pt_regs *, unsigned long, unsigned long);
21 
22 /*
23  * thread_struct is supposed to be for context switch data.
24  * Specifically, to hold the state necessary to perform switch_to...
25  */
26 struct thread_struct {
27 	void *switch_sp;
28 };
29 
30 /*
31  * initializes thread_struct
32  * The only thing we have in there is switch_sp
33  * which doesn't really need to be initialized.
34  */
35 
36 #define INIT_THREAD { \
37 }
38 
39 #define cpu_relax() __vmyield()
40 
41 /*
42  * Decides where the kernel will search for a free chunk of vm space during
43  * mmaps.
44  * See also arch_get_unmapped_area.
45  * Doesn't affect if you have MAX_FIXED in the page flags set though...
46  *
47  * Apparently the convention is that ld.so will ask for "unmapped" private
48  * memory to be allocated SOMEWHERE, but it also asks for memory explicitly
49  * via MAP_FIXED at the lower * addresses starting at VA=0x0.
50  *
51  * If the two requests collide, you get authentic segfaulting action, so
52  * you have to kick the "unmapped" base requests higher up.
53  */
54 #define TASK_UNMAPPED_BASE	(PAGE_ALIGN(TASK_SIZE/3))
55 
56 
57 #define task_pt_regs(task) \
58 	((struct pt_regs *)(task_stack_page(task) + THREAD_SIZE) - 1)
59 
60 #define KSTK_EIP(tsk) (pt_elr(task_pt_regs(tsk)))
61 #define KSTK_ESP(tsk) (pt_psp(task_pt_regs(tsk)))
62 
63 extern unsigned long __get_wchan(struct task_struct *p);
64 
65 /*  The following stuff is pretty HEXAGON specific.  */
66 
67 /*  This is really just here for __switch_to.
68     Offsets are pulled via asm-offsets.c  */
69 
70 /*
71  * No real reason why VM and native switch stacks should be different.
72  * Ultimately this should merge.  Note that Rev C. ABI called out only
73  * R24-27 as callee saved GPRs needing explicit attention (R29-31 being
74  * dealt with automagically by allocframe), but the current ABI has
75  * more, R16-R27.  By saving more, the worst case is that we waste some
76  * cycles if building with the old compilers.
77  */
78 
79 struct hexagon_switch_stack {
80 	union {
81 		struct {
82 			unsigned long r16;
83 			unsigned long r17;
84 		};
85 		unsigned long long	r1716;
86 	};
87 	union {
88 		struct {
89 			unsigned long r18;
90 			unsigned long r19;
91 		};
92 		unsigned long long	r1918;
93 	};
94 	union {
95 		struct {
96 			unsigned long r20;
97 			unsigned long r21;
98 		};
99 		unsigned long long	r2120;
100 	};
101 	union {
102 		struct {
103 			unsigned long r22;
104 			unsigned long r23;
105 		};
106 		unsigned long long	r2322;
107 	};
108 	union {
109 		struct {
110 			unsigned long r24;
111 			unsigned long r25;
112 		};
113 		unsigned long long	r2524;
114 	};
115 	union {
116 		struct {
117 			unsigned long r26;
118 			unsigned long r27;
119 		};
120 		unsigned long long	r2726;
121 	};
122 
123 	unsigned long		fp;
124 	unsigned long		lr;
125 };
126 
127 #endif /* !__ASSEMBLY__ */
128 
129 #endif
130