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f570b626 A |
1 | /* |
2 | * Code to prepare detour buffer for optprobes in Kernel. | |
3 | * | |
4 | * Copyright 2017, Anju T, IBM Corp. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #include <asm/ppc_asm.h> | |
13 | #include <asm/ptrace.h> | |
14 | #include <asm/asm-offsets.h> | |
15 | ||
16 | #define OPT_SLOT_SIZE 65536 | |
17 | ||
18 | .balign 4 | |
19 | ||
20 | /* | |
21 | * Reserve an area to allocate slots for detour buffer. | |
22 | * This is part of .text section (rather than vmalloc area) | |
23 | * as this needs to be within 32MB of the probed address. | |
24 | */ | |
25 | .global optinsn_slot | |
26 | optinsn_slot: | |
27 | .space OPT_SLOT_SIZE | |
28 | ||
29 | /* | |
30 | * Optprobe template: | |
31 | * This template gets copied into one of the slots in optinsn_slot | |
32 | * and gets fixed up with real optprobe structures et al. | |
33 | */ | |
34 | .global optprobe_template_entry | |
35 | optprobe_template_entry: | |
36 | /* Create an in-memory pt_regs */ | |
37 | stdu r1,-INT_FRAME_SIZE(r1) | |
38 | SAVE_GPR(0,r1) | |
39 | /* Save the previous SP into stack */ | |
40 | addi r0,r1,INT_FRAME_SIZE | |
41 | std r0,GPR1(r1) | |
42 | SAVE_10GPRS(2,r1) | |
43 | SAVE_10GPRS(12,r1) | |
44 | SAVE_10GPRS(22,r1) | |
45 | /* Save SPRS */ | |
46 | mfmsr r5 | |
47 | std r5,_MSR(r1) | |
48 | li r5,0x700 | |
49 | std r5,_TRAP(r1) | |
50 | li r5,0 | |
51 | std r5,ORIG_GPR3(r1) | |
52 | std r5,RESULT(r1) | |
53 | mfctr r5 | |
54 | std r5,_CTR(r1) | |
55 | mflr r5 | |
56 | std r5,_LINK(r1) | |
57 | mfspr r5,SPRN_XER | |
58 | std r5,_XER(r1) | |
59 | mfcr r5 | |
60 | std r5,_CCR(r1) | |
61 | lbz r5,PACASOFTIRQEN(r13) | |
62 | std r5,SOFTE(r1) | |
63 | mfdar r5 | |
64 | std r5,_DAR(r1) | |
65 | mfdsisr r5 | |
66 | std r5,_DSISR(r1) | |
67 | ||
eecb7258 NR |
68 | /* |
69 | * We may get here from a module, so load the kernel TOC in r2. | |
70 | * The original TOC gets restored when pt_regs is restored | |
71 | * further below. | |
72 | */ | |
73 | ld r2,PACATOC(r13) | |
74 | ||
f570b626 A |
75 | .global optprobe_template_op_address |
76 | optprobe_template_op_address: | |
77 | /* | |
78 | * Parameters to optimized_callback(): | |
79 | * 1. optimized_kprobe structure in r3 | |
80 | */ | |
81 | nop | |
82 | nop | |
83 | nop | |
84 | nop | |
85 | nop | |
86 | /* 2. pt_regs pointer in r4 */ | |
87 | addi r4,r1,STACK_FRAME_OVERHEAD | |
88 | ||
89 | .global optprobe_template_call_handler | |
90 | optprobe_template_call_handler: | |
91 | /* Branch to optimized_callback() */ | |
92 | nop | |
93 | ||
94 | /* | |
95 | * Parameters for instruction emulation: | |
96 | * 1. Pass SP in register r3. | |
97 | */ | |
98 | addi r3,r1,STACK_FRAME_OVERHEAD | |
99 | ||
100 | .global optprobe_template_insn | |
101 | optprobe_template_insn: | |
102 | /* 2, Pass instruction to be emulated in r4 */ | |
103 | nop | |
104 | nop | |
105 | ||
106 | .global optprobe_template_call_emulate | |
107 | optprobe_template_call_emulate: | |
108 | /* Branch to emulate_step() */ | |
109 | nop | |
110 | ||
111 | /* | |
112 | * All done. | |
113 | * Now, restore the registers... | |
114 | */ | |
115 | ld r5,_MSR(r1) | |
116 | mtmsr r5 | |
117 | ld r5,_CTR(r1) | |
118 | mtctr r5 | |
119 | ld r5,_LINK(r1) | |
120 | mtlr r5 | |
121 | ld r5,_XER(r1) | |
122 | mtxer r5 | |
123 | ld r5,_CCR(r1) | |
124 | mtcr r5 | |
125 | ld r5,_DAR(r1) | |
126 | mtdar r5 | |
127 | ld r5,_DSISR(r1) | |
128 | mtdsisr r5 | |
129 | REST_GPR(0,r1) | |
130 | REST_10GPRS(2,r1) | |
131 | REST_10GPRS(12,r1) | |
132 | REST_10GPRS(22,r1) | |
133 | /* Restore the previous SP */ | |
134 | addi r1,r1,INT_FRAME_SIZE | |
135 | ||
136 | .global optprobe_template_ret | |
137 | optprobe_template_ret: | |
138 | /* ... and jump back from trampoline */ | |
139 | nop | |
140 | ||
141 | .global optprobe_template_end | |
142 | optprobe_template_end: |