1 /*
2 * Copyright (c) 2004, 2025, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2014, 2020, Red Hat Inc. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "asm/macroAssembler.hpp"
27 #include "gc/shared/barrierSet.hpp"
28 #include "gc/shared/barrierSetAssembler.hpp"
29 #include "memory/resourceArea.hpp"
30 #include "prims/jniFastGetField.hpp"
31 #include "prims/jvm_misc.hpp"
32 #include "prims/jvmtiExport.hpp"
33 #include "runtime/javaThread.inline.hpp"
34 #include "runtime/safepoint.hpp"
35 #include "runtime/threadWXSetters.inline.hpp"
36
37 #define __ masm->
38
39 #define BUFFER_SIZE 30*wordSize
40
41 // Instead of issuing a LoadLoad barrier we create an address
42 // dependency between loads; this might be more efficient.
43
44 // Common register usage:
45 // r0/v0: result
46 // c_rarg0: jni env
47 // c_rarg1: obj
48 // c_rarg2: jfield id
49
50 static const Register robj = r3;
51 static const Register rcounter = r4;
52 static const Register roffset = r5;
53 static const Register rcounter_addr = r6;
54 static const Register result = r7;
55
56 // On macos/aarch64 we need to ensure WXExec mode when running generated
57 // FastGetXXXField, as these functions can be called from WXWrite context
58 // (8262896). So each FastGetXXXField is wrapped into a C++ statically
59 // compiled template function that optionally switches to WXExec if necessary.
60
61 #ifdef __APPLE__
62
63 static address generated_fast_get_field[T_LONG + 1 - T_BOOLEAN];
64
65 template<int BType> struct BasicTypeToJni {};
66 template<> struct BasicTypeToJni<T_BOOLEAN> { static const jboolean jni_type; };
67 template<> struct BasicTypeToJni<T_BYTE> { static const jbyte jni_type; };
68 template<> struct BasicTypeToJni<T_CHAR> { static const jchar jni_type; };
69 template<> struct BasicTypeToJni<T_SHORT> { static const jshort jni_type; };
70 template<> struct BasicTypeToJni<T_INT> { static const jint jni_type; };
71 template<> struct BasicTypeToJni<T_LONG> { static const jlong jni_type; };
72 template<> struct BasicTypeToJni<T_FLOAT> { static const jfloat jni_type; };
73 template<> struct BasicTypeToJni<T_DOUBLE> { static const jdouble jni_type; };
74
75 template<int BType, typename JniType = decltype(BasicTypeToJni<BType>::jni_type)>
76 JniType static_fast_get_field_wrapper(JNIEnv *env, jobject obj, jfieldID fieldID) {
77 JavaThread* thread = JavaThread::thread_from_jni_environment(env);
78 ThreadWXEnable wx(WXExec, thread);
79 address get_field_addr = generated_fast_get_field[BType - T_BOOLEAN];
80 return ((JniType(*)(JNIEnv *env, jobject obj, jfieldID fieldID))get_field_addr)(env, obj, fieldID);
81 }
82
83 template<int BType>
84 address JNI_FastGetField::generate_fast_get_int_field1() {
85 generated_fast_get_field[BType - T_BOOLEAN] = generate_fast_get_int_field0((BasicType)BType);
86 return (address)static_fast_get_field_wrapper<BType>;
87 }
88
89 #else // __APPLE__
90
91 template<int BType>
92 address JNI_FastGetField::generate_fast_get_int_field1() {
93 return generate_fast_get_int_field0((BasicType)BType);
94 }
95
96 #endif // __APPLE__
97
98 address JNI_FastGetField::generate_fast_get_int_field0(BasicType type) {
99 const char *name;
100 switch (type) {
101 case T_BOOLEAN: name = "jni_fast_GetBooleanField"; break;
102 case T_BYTE: name = "jni_fast_GetByteField"; break;
103 case T_CHAR: name = "jni_fast_GetCharField"; break;
104 case T_SHORT: name = "jni_fast_GetShortField"; break;
105 case T_INT: name = "jni_fast_GetIntField"; break;
106 case T_LONG: name = "jni_fast_GetLongField"; break;
107 case T_FLOAT: name = "jni_fast_GetFloatField"; break;
108 case T_DOUBLE: name = "jni_fast_GetDoubleField"; break;
109 default: ShouldNotReachHere();
110 name = nullptr; // unreachable
111 }
112 ResourceMark rm;
113 BufferBlob* blob = BufferBlob::create(name, BUFFER_SIZE);
114 CodeBuffer cbuf(blob);
115 MacroAssembler* masm = new MacroAssembler(&cbuf);
116 address fast_entry = __ pc();
117
118 Label slow;
119
120 uint64_t offset;
121 __ adrp(rcounter_addr,
122 SafepointSynchronize::safepoint_counter_addr(), offset);
123 Address safepoint_counter_addr(rcounter_addr, offset);
124 __ ldrw(rcounter, safepoint_counter_addr);
125 __ tbnz(rcounter, 0, slow);
126
127 // It doesn't need to issue a full barrier here even if the field
128 // is volatile, since it has already used "ldar" for it.
129 if (JvmtiExport::can_post_field_access()) {
130 // Using barrier to order wrt. JVMTI check and load of result.
131 __ membar(Assembler::LoadLoad);
132
133 // Check to see if a field access watch has been set before we
134 // take the fast path.
135 uint64_t offset2;
136 __ adrp(result,
137 ExternalAddress((address) JvmtiExport::get_field_access_count_addr()),
138 offset2);
139 __ ldrw(result, Address(result, offset2));
140 __ cbnzw(result, slow);
141
142 __ mov(robj, c_rarg1);
143 } else {
144 // Using address dependency to order wrt. load of result.
145 __ eor(robj, c_rarg1, rcounter);
146 __ eor(robj, robj, rcounter); // obj, since
147 // robj ^ rcounter ^ rcounter == robj
148 // robj is address dependent on rcounter.
149 }
150
151 // Both robj and rscratch1 are clobbered by try_resolve_jobject_in_native.
152 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
153 bs->try_resolve_jobject_in_native(masm, c_rarg0, robj, rscratch1, slow);
154
155 __ lsr(roffset, c_rarg2, 2); // offset
156 __ add(result, robj, roffset);
157
158 assert(count < LIST_CAPACITY, "LIST_CAPACITY too small");
159 speculative_load_pclist[count] = __ pc(); // Used by the segfault handler
160 // Using acquire: Order JVMTI check and load of result wrt. succeeding check
161 // (LoadStore for volatile field).
162 switch (type) {
163 case T_BOOLEAN: __ ldarb(result, result); break;
164 case T_BYTE: __ ldarb(result, result); __ sxtb(result, result); break;
165 case T_CHAR: __ ldarh(result, result); break;
166 case T_SHORT: __ ldarh(result, result); __ sxth(result, result); break;
167 case T_FLOAT: __ ldarw(result, result); break;
168 case T_INT: __ ldarw(result, result); __ sxtw(result, result); break;
169 case T_DOUBLE:
170 case T_LONG: __ ldar (result, result); break;
171 default: ShouldNotReachHere();
172 }
173
174 __ ldrw(rscratch1, safepoint_counter_addr);
175 __ cmpw(rcounter, rscratch1);
176 __ br (Assembler::NE, slow);
177
178 switch (type) {
179 case T_FLOAT: __ fmovs(v0, result); break;
180 case T_DOUBLE: __ fmovd(v0, result); break;
181 default: __ mov(r0, result); break;
182 }
183 __ ret(lr);
184
185 slowcase_entry_pclist[count++] = __ pc();
186 __ bind(slow);
187 address slow_case_addr;
188 switch (type) {
189 case T_BOOLEAN: slow_case_addr = jni_GetBooleanField_addr(); break;
190 case T_BYTE: slow_case_addr = jni_GetByteField_addr(); break;
191 case T_CHAR: slow_case_addr = jni_GetCharField_addr(); break;
192 case T_SHORT: slow_case_addr = jni_GetShortField_addr(); break;
193 case T_INT: slow_case_addr = jni_GetIntField_addr(); break;
194 case T_LONG: slow_case_addr = jni_GetLongField_addr(); break;
195 case T_FLOAT: slow_case_addr = jni_GetFloatField_addr(); break;
196 case T_DOUBLE: slow_case_addr = jni_GetDoubleField_addr(); break;
197 default: ShouldNotReachHere();
198 slow_case_addr = nullptr; // unreachable
199 }
200
201 {
202 __ enter();
203 __ lea(rscratch1, RuntimeAddress(slow_case_addr));
204 __ blr(rscratch1);
205 __ leave();
206 __ ret(lr);
207 }
208 __ flush ();
209
210 return fast_entry;
211 }
212
213 address JNI_FastGetField::generate_fast_get_boolean_field() {
214 return generate_fast_get_int_field1<T_BOOLEAN>();
215 }
216
217 address JNI_FastGetField::generate_fast_get_byte_field() {
218 return generate_fast_get_int_field1<T_BYTE>();
219 }
220
221 address JNI_FastGetField::generate_fast_get_char_field() {
222 return generate_fast_get_int_field1<T_CHAR>();
223 }
224
225 address JNI_FastGetField::generate_fast_get_short_field() {
226 return generate_fast_get_int_field1<T_SHORT>();
227 }
228
229 address JNI_FastGetField::generate_fast_get_int_field() {
230 return generate_fast_get_int_field1<T_INT>();
231 }
232
233 address JNI_FastGetField::generate_fast_get_long_field() {
234 return generate_fast_get_int_field1<T_LONG>();
235 }
236
237 address JNI_FastGetField::generate_fast_get_float_field() {
238 return generate_fast_get_int_field1<T_FLOAT>();
239 }
240
241 address JNI_FastGetField::generate_fast_get_double_field() {
242 return generate_fast_get_int_field1<T_DOUBLE>();
243 }