Commit | Line | Data |
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1da177e4 | 1 | /* |
a23ba435 | 2 | * arch/sh/kernel/cpu/sh5/switchto.S |
1da177e4 LT |
3 | * |
4 | * sh64 context switch | |
5 | * | |
6 | * Copyright (C) 2004 Richard Curnow | |
7 | * | |
8 | * This file is subject to the terms and conditions of the GNU General Public | |
9 | * License. See the file "COPYING" in the main directory of this archive | |
10 | * for more details. | |
11 | */ | |
12 | ||
13 | .section .text..SHmedia32,"ax" | |
14 | .little | |
15 | ||
16 | .balign 32 | |
17 | ||
18 | .type sh64_switch_to,@function | |
19 | .global sh64_switch_to | |
20 | .global __sh64_switch_to_end | |
21 | sh64_switch_to: | |
22 | ||
23 | /* Incoming args | |
24 | r2 - prev | |
25 | r3 - &prev->thread | |
26 | r4 - next | |
27 | r5 - &next->thread | |
28 | ||
29 | Outgoing results | |
30 | r2 - last (=prev) : this just stays in r2 throughout | |
31 | ||
32 | Want to create a full (struct pt_regs) on the stack to allow backtracing | |
33 | functions to work. However, we only need to populate the callee-save | |
34 | register slots in this structure; since we're a function our ancestors must | |
35 | have themselves preserved all caller saved state in the stack. This saves | |
36 | some wasted effort since we won't need to look at the values. | |
37 | ||
38 | In particular, all caller-save registers are immediately available for | |
39 | scratch use. | |
40 | ||
41 | */ | |
42 | ||
43 | #define FRAME_SIZE (76*8 + 8) | |
44 | ||
45 | movi FRAME_SIZE, r0 | |
46 | sub.l r15, r0, r15 | |
47 | ! Do normal-style register save to support backtrace | |
48 | ||
49 | st.l r15, 0, r18 ! save link reg | |
50 | st.l r15, 4, r14 ! save fp | |
51 | add.l r15, r63, r14 ! setup frame pointer | |
52 | ||
53 | ! hopefully this looks normal to the backtrace now. | |
54 | ||
55 | addi.l r15, 8, r1 ! base of pt_regs | |
56 | addi.l r1, 24, r0 ! base of pt_regs.regs | |
57 | addi.l r0, (63*8), r8 ! base of pt_regs.trregs | |
58 | ||
59 | /* Note : to be fixed? | |
60 | struct pt_regs is really designed for holding the state on entry | |
61 | to an exception, i.e. pc,sr,regs etc. However, for the context | |
62 | switch state, some of this is not required. But the unwinder takes | |
63 | struct pt_regs * as an arg so we have to build this structure | |
64 | to allow unwinding switched tasks in show_state() */ | |
65 | ||
66 | st.q r0, ( 9*8), r9 | |
67 | st.q r0, (10*8), r10 | |
68 | st.q r0, (11*8), r11 | |
69 | st.q r0, (12*8), r12 | |
70 | st.q r0, (13*8), r13 | |
71 | st.q r0, (14*8), r14 ! for unwind, want to look as though we took a trap at | |
72 | ! the point where the process is left in suspended animation, i.e. current | |
73 | ! fp here, not the saved one. | |
74 | st.q r0, (16*8), r16 | |
75 | ||
76 | st.q r0, (24*8), r24 | |
77 | st.q r0, (25*8), r25 | |
78 | st.q r0, (26*8), r26 | |
79 | st.q r0, (27*8), r27 | |
80 | st.q r0, (28*8), r28 | |
81 | st.q r0, (29*8), r29 | |
82 | st.q r0, (30*8), r30 | |
83 | st.q r0, (31*8), r31 | |
84 | st.q r0, (32*8), r32 | |
85 | st.q r0, (33*8), r33 | |
86 | st.q r0, (34*8), r34 | |
87 | st.q r0, (35*8), r35 | |
88 | ||
89 | st.q r0, (44*8), r44 | |
90 | st.q r0, (45*8), r45 | |
91 | st.q r0, (46*8), r46 | |
92 | st.q r0, (47*8), r47 | |
93 | st.q r0, (48*8), r48 | |
94 | st.q r0, (49*8), r49 | |
95 | st.q r0, (50*8), r50 | |
96 | st.q r0, (51*8), r51 | |
97 | st.q r0, (52*8), r52 | |
98 | st.q r0, (53*8), r53 | |
99 | st.q r0, (54*8), r54 | |
100 | st.q r0, (55*8), r55 | |
101 | st.q r0, (56*8), r56 | |
102 | st.q r0, (57*8), r57 | |
103 | st.q r0, (58*8), r58 | |
104 | st.q r0, (59*8), r59 | |
105 | ||
106 | ! do this early as pta->gettr has no pipeline forwarding (=> 5 cycle latency) | |
107 | ! Use a local label to avoid creating a symbol that will confuse the ! | |
108 | ! backtrace | |
109 | pta .Lsave_pc, tr0 | |
110 | ||
111 | gettr tr5, r45 | |
112 | gettr tr6, r46 | |
113 | gettr tr7, r47 | |
114 | st.q r8, (5*8), r45 | |
115 | st.q r8, (6*8), r46 | |
116 | st.q r8, (7*8), r47 | |
117 | ||
118 | ! Now switch context | |
119 | gettr tr0, r9 | |
120 | st.l r3, 0, r15 ! prev->thread.sp | |
121 | st.l r3, 8, r1 ! prev->thread.kregs | |
122 | st.l r3, 4, r9 ! prev->thread.pc | |
123 | st.q r1, 0, r9 ! save prev->thread.pc into pt_regs->pc | |
124 | ||
125 | ! Load PC for next task (init value or save_pc later) | |
126 | ld.l r5, 4, r18 ! next->thread.pc | |
127 | ! Switch stacks | |
128 | ld.l r5, 0, r15 ! next->thread.sp | |
129 | ptabs r18, tr0 | |
130 | ||
131 | ! Update current | |
132 | ld.l r4, 4, r9 ! next->thread_info (2nd element of next task_struct) | |
133 | putcon r9, kcr0 ! current = next->thread_info | |
134 | ||
135 | ! go to save_pc for a reschedule, or the initial thread.pc for a new process | |
136 | blink tr0, r63 | |
137 | ||
138 | ! Restore (when we come back to a previously saved task) | |
139 | .Lsave_pc: | |
140 | addi.l r15, 32, r0 ! r0 = next's regs | |
141 | addi.l r0, (63*8), r8 ! r8 = next's tr_regs | |
142 | ||
143 | ld.q r8, (5*8), r45 | |
144 | ld.q r8, (6*8), r46 | |
145 | ld.q r8, (7*8), r47 | |
146 | ptabs r45, tr5 | |
147 | ptabs r46, tr6 | |
148 | ptabs r47, tr7 | |
149 | ||
150 | ld.q r0, ( 9*8), r9 | |
151 | ld.q r0, (10*8), r10 | |
152 | ld.q r0, (11*8), r11 | |
153 | ld.q r0, (12*8), r12 | |
154 | ld.q r0, (13*8), r13 | |
155 | ld.q r0, (14*8), r14 | |
156 | ld.q r0, (16*8), r16 | |
157 | ||
158 | ld.q r0, (24*8), r24 | |
159 | ld.q r0, (25*8), r25 | |
160 | ld.q r0, (26*8), r26 | |
161 | ld.q r0, (27*8), r27 | |
162 | ld.q r0, (28*8), r28 | |
163 | ld.q r0, (29*8), r29 | |
164 | ld.q r0, (30*8), r30 | |
165 | ld.q r0, (31*8), r31 | |
166 | ld.q r0, (32*8), r32 | |
167 | ld.q r0, (33*8), r33 | |
168 | ld.q r0, (34*8), r34 | |
169 | ld.q r0, (35*8), r35 | |
170 | ||
171 | ld.q r0, (44*8), r44 | |
172 | ld.q r0, (45*8), r45 | |
173 | ld.q r0, (46*8), r46 | |
174 | ld.q r0, (47*8), r47 | |
175 | ld.q r0, (48*8), r48 | |
176 | ld.q r0, (49*8), r49 | |
177 | ld.q r0, (50*8), r50 | |
178 | ld.q r0, (51*8), r51 | |
179 | ld.q r0, (52*8), r52 | |
180 | ld.q r0, (53*8), r53 | |
181 | ld.q r0, (54*8), r54 | |
182 | ld.q r0, (55*8), r55 | |
183 | ld.q r0, (56*8), r56 | |
184 | ld.q r0, (57*8), r57 | |
185 | ld.q r0, (58*8), r58 | |
186 | ld.q r0, (59*8), r59 | |
187 | ||
188 | ! epilogue | |
189 | ld.l r15, 0, r18 | |
190 | ld.l r15, 4, r14 | |
191 | ptabs r18, tr0 | |
192 | movi FRAME_SIZE, r0 | |
193 | add r15, r0, r15 | |
194 | blink tr0, r63 | |
195 | __sh64_switch_to_end: | |
196 | .LFE1: | |
197 | .size sh64_switch_to,.LFE1-sh64_switch_to | |
198 |