diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/sh64/kernel/switchto.S |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/sh64/kernel/switchto.S')
-rw-r--r-- | arch/sh64/kernel/switchto.S | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/arch/sh64/kernel/switchto.S b/arch/sh64/kernel/switchto.S new file mode 100644 index 000000000000..45b2d90eed7d --- /dev/null +++ b/arch/sh64/kernel/switchto.S | |||
@@ -0,0 +1,198 @@ | |||
1 | /* | ||
2 | * arch/sh64/kernel/switchto.S | ||
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 | |||