1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
|
/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "asm_support_arm.S"
/*
* Jni dlsym lookup stub.
*/
.extern artFindNativeMethod
.extern artFindNativeMethodRunnable
ENTRY art_jni_dlsym_lookup_stub
push {r0, r1, r2, r3, lr} @ spill regs
.cfi_adjust_cfa_offset 20
.cfi_rel_offset lr, 16
sub sp, #12 @ pad stack pointer to align frame
.cfi_adjust_cfa_offset 12
mov r0, rSELF @ pass Thread::Current()
// Call artFindNativeMethod() for normal native and artFindNativeMethodRunnable()
// for @FastNative or @CriticalNative.
ldr ip, [r0, #THREAD_TOP_QUICK_FRAME_OFFSET] // uintptr_t tagged_quick_frame
bic ip, #1 // ArtMethod** sp
ldr ip, [ip] // ArtMethod* method
ldr ip, [ip, #ART_METHOD_ACCESS_FLAGS_OFFSET] // uint32_t access_flags
tst ip, #(ACCESS_FLAGS_METHOD_IS_FAST_NATIVE | ACCESS_FLAGS_METHOD_IS_CRITICAL_NATIVE)
bne .Llookup_stub_fast_or_critical_native
blx artFindNativeMethod
b .Llookup_stub_continue
.Llookup_stub_fast_or_critical_native:
blx artFindNativeMethodRunnable
.Llookup_stub_continue:
mov r12, r0 @ save result in r12
add sp, #12 @ restore stack pointer
.cfi_adjust_cfa_offset -12
cbz r0, 1f @ is method code null?
pop {r0, r1, r2, r3, lr} @ restore regs
.cfi_adjust_cfa_offset -20
.cfi_restore lr
bx r12 @ if non-null, tail call to method's code
1:
pop {r0, r1, r2, r3, pc} @ restore regs and return to caller to handle exception
END art_jni_dlsym_lookup_stub
ENTRY art_jni_dlsym_lookup_critical_stub
// The hidden arg holding the tagged method (bit 0 set means GenericJNI) is r4.
// For Generic JNI we already have a managed frame, so we reuse the art_jni_dlsym_lookup_stub.
tst r4, #1
bne art_jni_dlsym_lookup_stub
// Reserve space for a SaveRefsAndArgs managed frame, either for the actual runtime
// method or for a GenericJNI frame which is similar but has a native method and a tag.
// Do this eagerly, so that we can use these registers as temps without the need to
// save and restore them multiple times.
INCREASE_FRAME FRAME_SIZE_SAVE_REFS_AND_ARGS
// Save args, the hidden arg and caller PC. No CFI needed for args and the hidden arg.
push {r0, r1, r2, r3, r4, lr}
.cfi_adjust_cfa_offset 24
.cfi_rel_offset lr, 20
// Call artCriticalNativeFrameSize(method, caller_pc)
mov r0, r4 // r0 := method (from hidden arg)
mov r1, lr // r1 := caller_pc
bl artCriticalNativeFrameSize
// Prepare the return address for managed stack walk of the SaveRefsAndArgs frame.
// If we're coming from JNI stub with tail call, it is LR. If we're coming from
// JNI stub that saved the return address, it will be the last value we copy below.
// If we're coming directly from compiled code, it is LR, set further down.
ldr lr, [sp, #20]
// Move the stack args if any.
add r4, sp, #24
cbz r0, .Lcritical_skip_copy_args
.Lcritical_copy_args_loop:
ldrd ip, lr, [r4, #FRAME_SIZE_SAVE_REFS_AND_ARGS]
subs r0, r0, #8
strd ip, lr, [r4], #8
bne .Lcritical_copy_args_loop
.Lcritical_skip_copy_args:
// The managed frame address is now in R4. This is conveniently a callee-save in native ABI.
// Restore args.
pop {r0, r1, r2, r3}
.cfi_adjust_cfa_offset -16
// Spill registers for the SaveRefsAndArgs frame above the stack args.
// Note that the runtime shall not examine the args here, otherwise we would have to
// move them in registers and stack to account for the difference between managed and
// native ABIs.
add ip, r4, #FRAME_SIZE_SAVE_REFS_AND_ARGS - 40
stmia ip, {r1-r3, r5-r8, r10-r11, lr} // LR: Save return address for tail call from JNI stub.
// (If there were any stack args, we're storing the value that's already there.
// For direct calls from compiled managed code, we shall overwrite this below.)
// Skip args r1-r3.
CFI_EXPRESSION_BREG 5, 4, FRAME_SIZE_SAVE_REFS_AND_ARGS - 28
CFI_EXPRESSION_BREG 6, 4, FRAME_SIZE_SAVE_REFS_AND_ARGS - 24
CFI_EXPRESSION_BREG 7, 4, FRAME_SIZE_SAVE_REFS_AND_ARGS - 20
CFI_EXPRESSION_BREG 8, 4, FRAME_SIZE_SAVE_REFS_AND_ARGS - 16
CFI_EXPRESSION_BREG 10, 4, FRAME_SIZE_SAVE_REFS_AND_ARGS - 12
CFI_EXPRESSION_BREG 11, 4, FRAME_SIZE_SAVE_REFS_AND_ARGS - 8
// The saved return PC for managed stack walk is not necessarily our LR.
// Skip managed FP args as these are native ABI caller-saves and not args.
// Restore the hidden arg to r1 and caller PC.
pop {r1, lr}
.cfi_adjust_cfa_offset -8
.cfi_restore lr
// Save our return PC in the padding.
str lr, [r4, #__SIZEOF_POINTER__]
CFI_EXPRESSION_BREG 14, 4, __SIZEOF_POINTER__
ldr ip, [r1, #ART_METHOD_ACCESS_FLAGS_OFFSET] // Load access flags.
add r2, r4, #1 // Prepare managed SP tagged for a GenericJNI frame.
tst ip, #ACCESS_FLAGS_METHOD_IS_NATIVE
bne .Lcritical_skip_prepare_runtime_method
// When coming from a compiled method, the return PC for managed stack walk is LR.
// (When coming from a compiled stub, the correct return PC is already stored above.)
str lr, [r4, #(FRAME_SIZE_SAVE_REFS_AND_ARGS - __SIZEOF_POINTER__)]
// Replace the target method with the SaveRefsAndArgs runtime method.
RUNTIME_CURRENT1 r1
ldr r1, [r1, #RUNTIME_SAVE_REFS_AND_ARGS_METHOD_OFFSET]
mov r2, r4 // Prepare untagged managed SP for the runtime method.
.Lcritical_skip_prepare_runtime_method:
// Store the method on the bottom of the managed frame.
str r1, [r4]
// Place (maybe tagged) managed SP in Thread::Current()->top_quick_frame.
str r2, [rSELF, #THREAD_TOP_QUICK_FRAME_OFFSET]
// Preserve the native arg register r0 in callee-save register r10 which was saved above.
mov r10, r0
// Call artFindNativeMethodRunnable()
mov r0, rSELF // pass Thread::Current()
bl artFindNativeMethodRunnable
// Store result in scratch reg.
mov ip, r0
// Restore the native arg register r0.
mov r0, r10
// Restore the frame. We shall not need the method anymore.
add r1, r4, #FRAME_SIZE_SAVE_REFS_AND_ARGS - 40
ldmia r1, {r1-r3, r5-r8, r10-r11}
.cfi_restore r5
.cfi_restore r6
.cfi_restore r7
.cfi_restore r8
.cfi_restore r10
.cfi_restore r11
REFRESH_MARKING_REGISTER
// Check for exception before moving args back to keep the return PC for managed stack walk.
cmp ip, #0
beq .Lcritical_deliver_exception
.cfi_remember_state
// Restore our return PC.
ldr lr, [r4, #__SIZEOF_POINTER__]
.cfi_restore lr
// Move stack args to their original place.
cmp sp, r4
beq .Lcritical_skip_copy_args_back
push {r0, r1, r2, r3}
.cfi_adjust_cfa_offset 16
add r0, sp, #16
sub r0, r4, r0
.Lcritical_copy_args_loop_back:
ldrd r2, r3, [r4, #-8]!
subs r0, r0, #8
strd r2, r3, [r4, #FRAME_SIZE_SAVE_REFS_AND_ARGS]
bne .Lcritical_copy_args_loop_back
pop {r0, r1, r2, r3}
.cfi_adjust_cfa_offset -16
.Lcritical_skip_copy_args_back:
// Remove the frame reservation.
DECREASE_FRAME FRAME_SIZE_SAVE_REFS_AND_ARGS
// Do the tail call.
bx ip
.cfi_restore_state
.cfi_def_cfa sp, FRAME_SIZE_SAVE_REFS_AND_ARGS
.Lcritical_deliver_exception:
// The exception delivery checks that rSELF was saved but the SaveRefsAndArgs
// frame does not save it, so we cannot use the existing SaveRefsAndArgs frame.
// That's why we checked for exception after restoring registers from it.
// We need to build a SaveAllCalleeSaves frame instead. Args are irrelevant at this
// point but keep the area allocated for stack args to keep CFA definition simple.
#if FRAME_SIZE_SAVE_REFS_AND_ARGS != FRAME_SIZE_SAVE_ALL_CALLEE_SAVES
# error "Expected FRAME_SIZE_SAVE_REFS_AND_ARGS == FRAME_SIZE_SAVE_ALL_CALLEE_SAVES"
// Otherwise we would need to adjust SP and R4 and move our return PC which is at [R4, #4].
// (Luckily, both SaveRefsAndArgs and SaveAllCalleeSaves frames have padding there.)
#endif
// Spill registers for the SaveAllCalleeSaves frame above the stack args area.
add ip, r4, #FRAME_SIZE_SAVE_ALL_CALLEE_SAVES - 32
stmia ip, {r5-r11} // Keep the caller PC for managed stack walk.
CFI_EXPRESSION_BREG 5, 4, FRAME_SIZE_SAVE_ALL_CALLEE_SAVES - 32
CFI_EXPRESSION_BREG 6, 4, FRAME_SIZE_SAVE_ALL_CALLEE_SAVES - 28
CFI_EXPRESSION_BREG 7, 4, FRAME_SIZE_SAVE_ALL_CALLEE_SAVES - 24
CFI_EXPRESSION_BREG 8, 4, FRAME_SIZE_SAVE_ALL_CALLEE_SAVES - 20
CFI_EXPRESSION_BREG 9, 4, FRAME_SIZE_SAVE_ALL_CALLEE_SAVES - 16
CFI_EXPRESSION_BREG 10, 4, FRAME_SIZE_SAVE_ALL_CALLEE_SAVES - 12
CFI_EXPRESSION_BREG 11, 4, FRAME_SIZE_SAVE_ALL_CALLEE_SAVES - 8
// Skip R4, it is callee-save in managed ABI.
add ip, r4, #12
vstmia ip, {s16-s31}
// Store ArtMethod* Runtime::callee_save_methods_[kSaveAllCalleeSaves] to the managed frame.
RUNTIME_CURRENT2 ip
ldr ip, [ip, #RUNTIME_SAVE_ALL_CALLEE_SAVES_METHOD_OFFSET]
str ip, [r4]
// Place the managed frame SP in Thread::Current()->top_quick_frame.
str r4, [rSELF, #THREAD_TOP_QUICK_FRAME_OFFSET]
DELIVER_PENDING_EXCEPTION_FRAME_READY
END art_jni_dlsym_lookup_critical_stub
|
