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annotate src/cpu/x86/vm/nativeInst_x86.cpp @ 7780:550c952f5d3f
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author | Christian Humer <christian.humer@gmail.com> |
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date | Tue, 12 Feb 2013 16:06:20 +0100 |
parents | cd3d6a6b95d9 |
children | 78c808233ff1 78bbf4d43a14 |
rev | line source |
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0 | 1 /* |
1972 | 2 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved. |
0 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
4 * | |
5 * This code is free software; you can redistribute it and/or modify it | |
6 * under the terms of the GNU General Public License version 2 only, as | |
7 * published by the Free Software Foundation. | |
8 * | |
9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
12 * version 2 for more details (a copy is included in the LICENSE file that | |
13 * accompanied this code). | |
14 * | |
15 * You should have received a copy of the GNU General Public License version | |
16 * 2 along with this work; if not, write to the Free Software Foundation, | |
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
18 * | |
1552
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
1972 | 25 #include "precompiled.hpp" |
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26 #include "asm/macroAssembler.hpp" |
1972 | 27 #include "memory/resourceArea.hpp" |
28 #include "nativeInst_x86.hpp" | |
29 #include "oops/oop.inline.hpp" | |
30 #include "runtime/handles.hpp" | |
31 #include "runtime/sharedRuntime.hpp" | |
32 #include "runtime/stubRoutines.hpp" | |
33 #include "utilities/ostream.hpp" | |
34 #ifdef COMPILER1 | |
35 #include "c1/c1_Runtime1.hpp" | |
36 #endif | |
0 | 37 |
38 void NativeInstruction::wrote(int offset) { | |
39 ICache::invalidate_word(addr_at(offset)); | |
40 } | |
41 | |
42 | |
43 void NativeCall::verify() { | |
44 // Make sure code pattern is actually a call imm32 instruction. | |
45 int inst = ubyte_at(0); | |
46 if (inst != instruction_code) { | |
47 tty->print_cr("Addr: " INTPTR_FORMAT " Code: 0x%x", instruction_address(), | |
48 inst); | |
49 fatal("not a call disp32"); | |
50 } | |
51 } | |
52 | |
53 address NativeCall::destination() const { | |
54 // Getting the destination of a call isn't safe because that call can | |
55 // be getting patched while you're calling this. There's only special | |
56 // places where this can be called but not automatically verifiable by | |
57 // checking which locks are held. The solution is true atomic patching | |
58 // on x86, nyi. | |
59 return return_address() + displacement(); | |
60 } | |
61 | |
62 void NativeCall::print() { | |
63 tty->print_cr(PTR_FORMAT ": call " PTR_FORMAT, | |
64 instruction_address(), destination()); | |
65 } | |
66 | |
67 // Inserts a native call instruction at a given pc | |
68 void NativeCall::insert(address code_pos, address entry) { | |
69 intptr_t disp = (intptr_t)entry - ((intptr_t)code_pos + 1 + 4); | |
70 #ifdef AMD64 | |
71 guarantee(disp == (intptr_t)(jint)disp, "must be 32-bit offset"); | |
72 #endif // AMD64 | |
73 *code_pos = instruction_code; | |
74 *((int32_t *)(code_pos+1)) = (int32_t) disp; | |
75 ICache::invalidate_range(code_pos, instruction_size); | |
76 } | |
77 | |
78 // MT-safe patching of a call instruction. | |
79 // First patches first word of instruction to two jmp's that jmps to them | |
80 // selfs (spinlock). Then patches the last byte, and then atomicly replaces | |
81 // the jmp's with the first 4 byte of the new instruction. | |
82 void NativeCall::replace_mt_safe(address instr_addr, address code_buffer) { | |
83 assert(Patching_lock->is_locked() || | |
84 SafepointSynchronize::is_at_safepoint(), "concurrent code patching"); | |
85 assert (instr_addr != NULL, "illegal address for code patching"); | |
86 | |
87 NativeCall* n_call = nativeCall_at (instr_addr); // checking that it is a call | |
88 if (os::is_MP()) { | |
89 guarantee((intptr_t)instr_addr % BytesPerWord == 0, "must be aligned"); | |
90 } | |
91 | |
92 // First patch dummy jmp in place | |
93 unsigned char patch[4]; | |
94 assert(sizeof(patch)==sizeof(jint), "sanity check"); | |
95 patch[0] = 0xEB; // jmp rel8 | |
96 patch[1] = 0xFE; // jmp to self | |
97 patch[2] = 0xEB; | |
98 patch[3] = 0xFE; | |
99 | |
100 // First patch dummy jmp in place | |
101 *(jint*)instr_addr = *(jint *)patch; | |
102 | |
103 // Invalidate. Opteron requires a flush after every write. | |
104 n_call->wrote(0); | |
105 | |
106 // Patch 4th byte | |
107 instr_addr[4] = code_buffer[4]; | |
108 | |
109 n_call->wrote(4); | |
110 | |
111 // Patch bytes 0-3 | |
112 *(jint*)instr_addr = *(jint *)code_buffer; | |
113 | |
114 n_call->wrote(0); | |
115 | |
116 #ifdef ASSERT | |
117 // verify patching | |
118 for ( int i = 0; i < instruction_size; i++) { | |
119 address ptr = (address)((intptr_t)code_buffer + i); | |
120 int a_byte = (*ptr) & 0xFF; | |
121 assert(*((address)((intptr_t)instr_addr + i)) == a_byte, "mt safe patching failed"); | |
122 } | |
123 #endif | |
124 | |
125 } | |
126 | |
127 | |
128 // Similar to replace_mt_safe, but just changes the destination. The | |
129 // important thing is that free-running threads are able to execute this | |
130 // call instruction at all times. If the displacement field is aligned | |
131 // we can simply rely on atomicity of 32-bit writes to make sure other threads | |
132 // will see no intermediate states. Otherwise, the first two bytes of the | |
133 // call are guaranteed to be aligned, and can be atomically patched to a | |
134 // self-loop to guard the instruction while we change the other bytes. | |
135 | |
136 // We cannot rely on locks here, since the free-running threads must run at | |
137 // full speed. | |
138 // | |
139 // Used in the runtime linkage of calls; see class CompiledIC. | |
140 // (Cf. 4506997 and 4479829, where threads witnessed garbage displacements.) | |
141 void NativeCall::set_destination_mt_safe(address dest) { | |
142 debug_only(verify()); | |
143 // Make sure patching code is locked. No two threads can patch at the same | |
144 // time but one may be executing this code. | |
145 assert(Patching_lock->is_locked() || | |
146 SafepointSynchronize::is_at_safepoint(), "concurrent code patching"); | |
147 // Both C1 and C2 should now be generating code which aligns the patched address | |
148 // to be within a single cache line except that C1 does not do the alignment on | |
149 // uniprocessor systems. | |
150 bool is_aligned = ((uintptr_t)displacement_address() + 0) / cache_line_size == | |
151 ((uintptr_t)displacement_address() + 3) / cache_line_size; | |
152 | |
153 guarantee(!os::is_MP() || is_aligned, "destination must be aligned"); | |
154 | |
155 if (is_aligned) { | |
156 // Simple case: The destination lies within a single cache line. | |
157 set_destination(dest); | |
158 } else if ((uintptr_t)instruction_address() / cache_line_size == | |
159 ((uintptr_t)instruction_address()+1) / cache_line_size) { | |
160 // Tricky case: The instruction prefix lies within a single cache line. | |
161 intptr_t disp = dest - return_address(); | |
162 #ifdef AMD64 | |
163 guarantee(disp == (intptr_t)(jint)disp, "must be 32-bit offset"); | |
164 #endif // AMD64 | |
165 | |
166 int call_opcode = instruction_address()[0]; | |
167 | |
168 // First patch dummy jump in place: | |
169 { | |
170 u_char patch_jump[2]; | |
171 patch_jump[0] = 0xEB; // jmp rel8 | |
172 patch_jump[1] = 0xFE; // jmp to self | |
173 | |
174 assert(sizeof(patch_jump)==sizeof(short), "sanity check"); | |
175 *(short*)instruction_address() = *(short*)patch_jump; | |
176 } | |
177 // Invalidate. Opteron requires a flush after every write. | |
178 wrote(0); | |
179 | |
180 // (Note: We assume any reader which has already started to read | |
181 // the unpatched call will completely read the whole unpatched call | |
182 // without seeing the next writes we are about to make.) | |
183 | |
184 // Next, patch the last three bytes: | |
185 u_char patch_disp[5]; | |
186 patch_disp[0] = call_opcode; | |
187 *(int32_t*)&patch_disp[1] = (int32_t)disp; | |
188 assert(sizeof(patch_disp)==instruction_size, "sanity check"); | |
189 for (int i = sizeof(short); i < instruction_size; i++) | |
190 instruction_address()[i] = patch_disp[i]; | |
191 | |
192 // Invalidate. Opteron requires a flush after every write. | |
193 wrote(sizeof(short)); | |
194 | |
195 // (Note: We assume that any reader which reads the opcode we are | |
196 // about to repatch will also read the writes we just made.) | |
197 | |
198 // Finally, overwrite the jump: | |
199 *(short*)instruction_address() = *(short*)patch_disp; | |
200 // Invalidate. Opteron requires a flush after every write. | |
201 wrote(0); | |
202 | |
203 debug_only(verify()); | |
204 guarantee(destination() == dest, "patch succeeded"); | |
205 } else { | |
206 // Impossible: One or the other must be atomically writable. | |
207 ShouldNotReachHere(); | |
208 } | |
209 } | |
210 | |
211 | |
212 void NativeMovConstReg::verify() { | |
213 #ifdef AMD64 | |
214 // make sure code pattern is actually a mov reg64, imm64 instruction | |
215 if ((ubyte_at(0) != Assembler::REX_W && ubyte_at(0) != Assembler::REX_WB) || | |
216 (ubyte_at(1) & (0xff ^ register_mask)) != 0xB8) { | |
217 print(); | |
218 fatal("not a REX.W[B] mov reg64, imm64"); | |
219 } | |
220 #else | |
221 // make sure code pattern is actually a mov reg, imm32 instruction | |
222 u_char test_byte = *(u_char*)instruction_address(); | |
223 u_char test_byte_2 = test_byte & ( 0xff ^ register_mask); | |
224 if (test_byte_2 != instruction_code) fatal("not a mov reg, imm32"); | |
225 #endif // AMD64 | |
226 } | |
227 | |
228 | |
229 void NativeMovConstReg::print() { | |
230 tty->print_cr(PTR_FORMAT ": mov reg, " INTPTR_FORMAT, | |
231 instruction_address(), data()); | |
232 } | |
233 | |
234 //------------------------------------------------------------------- | |
235 | |
304 | 236 int NativeMovRegMem::instruction_start() const { |
237 int off = 0; | |
238 u_char instr_0 = ubyte_at(off); | |
239 | |
4759 | 240 // See comment in Assembler::locate_operand() about VEX prefixes. |
241 if (instr_0 == instruction_VEX_prefix_2bytes) { | |
242 assert((UseAVX > 0), "shouldn't have VEX prefix"); | |
243 NOT_LP64(assert((0xC0 & ubyte_at(1)) == 0xC0, "shouldn't have LDS and LES instructions")); | |
244 return 2; | |
245 } | |
246 if (instr_0 == instruction_VEX_prefix_3bytes) { | |
247 assert((UseAVX > 0), "shouldn't have VEX prefix"); | |
248 NOT_LP64(assert((0xC0 & ubyte_at(1)) == 0xC0, "shouldn't have LDS and LES instructions")); | |
249 return 3; | |
250 } | |
251 | |
304 | 252 // First check to see if we have a (prefixed or not) xor |
4759 | 253 if (instr_0 >= instruction_prefix_wide_lo && // 0x40 |
254 instr_0 <= instruction_prefix_wide_hi) { // 0x4f | |
304 | 255 off++; |
256 instr_0 = ubyte_at(off); | |
257 } | |
258 | |
259 if (instr_0 == instruction_code_xor) { | |
260 off += 2; | |
261 instr_0 = ubyte_at(off); | |
262 } | |
263 | |
264 // Now look for the real instruction and the many prefix/size specifiers. | |
265 | |
266 if (instr_0 == instruction_operandsize_prefix ) { // 0x66 | |
267 off++; // Not SSE instructions | |
268 instr_0 = ubyte_at(off); | |
269 } | |
0 | 270 |
4759 | 271 if ( instr_0 == instruction_code_xmm_ss_prefix || // 0xf3 |
304 | 272 instr_0 == instruction_code_xmm_sd_prefix) { // 0xf2 |
273 off++; | |
274 instr_0 = ubyte_at(off); | |
275 } | |
276 | |
4759 | 277 if ( instr_0 >= instruction_prefix_wide_lo && // 0x40 |
304 | 278 instr_0 <= instruction_prefix_wide_hi) { // 0x4f |
279 off++; | |
280 instr_0 = ubyte_at(off); | |
281 } | |
282 | |
283 | |
284 if (instr_0 == instruction_extended_prefix ) { // 0x0f | |
285 off++; | |
286 } | |
287 | |
288 return off; | |
289 } | |
290 | |
291 address NativeMovRegMem::instruction_address() const { | |
292 return addr_at(instruction_start()); | |
293 } | |
294 | |
295 address NativeMovRegMem::next_instruction_address() const { | |
296 address ret = instruction_address() + instruction_size; | |
297 u_char instr_0 = *(u_char*) instruction_address(); | |
298 switch (instr_0) { | |
299 case instruction_operandsize_prefix: | |
300 | |
301 fatal("should have skipped instruction_operandsize_prefix"); | |
302 break; | |
0 | 303 |
304 | 304 case instruction_extended_prefix: |
305 fatal("should have skipped instruction_extended_prefix"); | |
306 break; | |
307 | |
308 case instruction_code_mem2reg_movslq: // 0x63 | |
309 case instruction_code_mem2reg_movzxb: // 0xB6 | |
310 case instruction_code_mem2reg_movsxb: // 0xBE | |
311 case instruction_code_mem2reg_movzxw: // 0xB7 | |
312 case instruction_code_mem2reg_movsxw: // 0xBF | |
313 case instruction_code_reg2mem: // 0x89 (q/l) | |
314 case instruction_code_mem2reg: // 0x8B (q/l) | |
315 case instruction_code_reg2memb: // 0x88 | |
316 case instruction_code_mem2regb: // 0x8a | |
317 | |
318 case instruction_code_float_s: // 0xd9 fld_s a | |
319 case instruction_code_float_d: // 0xdd fld_d a | |
320 | |
321 case instruction_code_xmm_load: // 0x10 | |
322 case instruction_code_xmm_store: // 0x11 | |
323 case instruction_code_xmm_lpd: // 0x12 | |
324 { | |
325 // If there is an SIB then instruction is longer than expected | |
326 u_char mod_rm = *(u_char*)(instruction_address() + 1); | |
327 if ((mod_rm & 7) == 0x4) { | |
328 ret++; | |
329 } | |
330 } | |
331 case instruction_code_xor: | |
332 fatal("should have skipped xor lead in"); | |
333 break; | |
334 | |
335 default: | |
336 fatal("not a NativeMovRegMem"); | |
0 | 337 } |
304 | 338 return ret; |
339 | |
340 } | |
0 | 341 |
304 | 342 int NativeMovRegMem::offset() const{ |
343 int off = data_offset + instruction_start(); | |
344 u_char mod_rm = *(u_char*)(instruction_address() + 1); | |
345 // nnnn(r12|rsp) isn't coded as simple mod/rm since that is | |
346 // the encoding to use an SIB byte. Which will have the nnnn | |
347 // field off by one byte | |
348 if ((mod_rm & 7) == 0x4) { | |
349 off++; | |
0 | 350 } |
304 | 351 return int_at(off); |
352 } | |
353 | |
354 void NativeMovRegMem::set_offset(int x) { | |
355 int off = data_offset + instruction_start(); | |
356 u_char mod_rm = *(u_char*)(instruction_address() + 1); | |
357 // nnnn(r12|rsp) isn't coded as simple mod/rm since that is | |
358 // the encoding to use an SIB byte. Which will have the nnnn | |
359 // field off by one byte | |
360 if ((mod_rm & 7) == 0x4) { | |
361 off++; | |
362 } | |
363 set_int_at(off, x); | |
0 | 364 } |
365 | |
366 void NativeMovRegMem::verify() { | |
367 // make sure code pattern is actually a mov [reg+offset], reg instruction | |
368 u_char test_byte = *(u_char*)instruction_address(); | |
304 | 369 switch (test_byte) { |
370 case instruction_code_reg2memb: // 0x88 movb a, r | |
371 case instruction_code_reg2mem: // 0x89 movl a, r (can be movq in 64bit) | |
372 case instruction_code_mem2regb: // 0x8a movb r, a | |
373 case instruction_code_mem2reg: // 0x8b movl r, a (can be movq in 64bit) | |
374 break; | |
375 | |
376 case instruction_code_mem2reg_movslq: // 0x63 movsql r, a | |
377 case instruction_code_mem2reg_movzxb: // 0xb6 movzbl r, a (movzxb) | |
378 case instruction_code_mem2reg_movzxw: // 0xb7 movzwl r, a (movzxw) | |
379 case instruction_code_mem2reg_movsxb: // 0xbe movsbl r, a (movsxb) | |
380 case instruction_code_mem2reg_movsxw: // 0xbf movswl r, a (movsxw) | |
381 break; | |
382 | |
383 case instruction_code_float_s: // 0xd9 fld_s a | |
384 case instruction_code_float_d: // 0xdd fld_d a | |
385 case instruction_code_xmm_load: // 0x10 movsd xmm, a | |
386 case instruction_code_xmm_store: // 0x11 movsd a, xmm | |
387 case instruction_code_xmm_lpd: // 0x12 movlpd xmm, a | |
388 break; | |
389 | |
390 default: | |
0 | 391 fatal ("not a mov [reg+offs], reg instruction"); |
392 } | |
393 } | |
394 | |
395 | |
396 void NativeMovRegMem::print() { | |
397 tty->print_cr("0x%x: mov reg, [reg + %x]", instruction_address(), offset()); | |
398 } | |
399 | |
400 //------------------------------------------------------------------- | |
401 | |
402 void NativeLoadAddress::verify() { | |
403 // make sure code pattern is actually a mov [reg+offset], reg instruction | |
404 u_char test_byte = *(u_char*)instruction_address(); | |
304 | 405 #ifdef _LP64 |
406 if ( (test_byte == instruction_prefix_wide || | |
407 test_byte == instruction_prefix_wide_extended) ) { | |
408 test_byte = *(u_char*)(instruction_address() + 1); | |
409 } | |
410 #endif // _LP64 | |
411 if ( ! ((test_byte == lea_instruction_code) | |
412 LP64_ONLY(|| (test_byte == mov64_instruction_code) ))) { | |
0 | 413 fatal ("not a lea reg, [reg+offs] instruction"); |
414 } | |
415 } | |
416 | |
417 | |
418 void NativeLoadAddress::print() { | |
419 tty->print_cr("0x%x: lea [reg + %x], reg", instruction_address(), offset()); | |
420 } | |
421 | |
422 //-------------------------------------------------------------------------------- | |
423 | |
424 void NativeJump::verify() { | |
425 if (*(u_char*)instruction_address() != instruction_code) { | |
426 fatal("not a jump instruction"); | |
427 } | |
428 } | |
429 | |
430 | |
431 void NativeJump::insert(address code_pos, address entry) { | |
432 intptr_t disp = (intptr_t)entry - ((intptr_t)code_pos + 1 + 4); | |
433 #ifdef AMD64 | |
434 guarantee(disp == (intptr_t)(int32_t)disp, "must be 32-bit offset"); | |
435 #endif // AMD64 | |
436 | |
437 *code_pos = instruction_code; | |
438 *((int32_t*)(code_pos + 1)) = (int32_t)disp; | |
439 | |
440 ICache::invalidate_range(code_pos, instruction_size); | |
441 } | |
442 | |
443 void NativeJump::check_verified_entry_alignment(address entry, address verified_entry) { | |
444 // Patching to not_entrant can happen while activations of the method are | |
445 // in use. The patching in that instance must happen only when certain | |
446 // alignment restrictions are true. These guarantees check those | |
447 // conditions. | |
448 #ifdef AMD64 | |
449 const int linesize = 64; | |
450 #else | |
451 const int linesize = 32; | |
452 #endif // AMD64 | |
453 | |
454 // Must be wordSize aligned | |
455 guarantee(((uintptr_t) verified_entry & (wordSize -1)) == 0, | |
456 "illegal address for code patching 2"); | |
457 // First 5 bytes must be within the same cache line - 4827828 | |
458 guarantee((uintptr_t) verified_entry / linesize == | |
459 ((uintptr_t) verified_entry + 4) / linesize, | |
460 "illegal address for code patching 3"); | |
461 } | |
462 | |
463 | |
464 // MT safe inserting of a jump over an unknown instruction sequence (used by nmethod::makeZombie) | |
465 // The problem: jmp <dest> is a 5-byte instruction. Atomical write can be only with 4 bytes. | |
466 // First patches the first word atomically to be a jump to itself. | |
467 // Then patches the last byte and then atomically patches the first word (4-bytes), | |
468 // thus inserting the desired jump | |
469 // This code is mt-safe with the following conditions: entry point is 4 byte aligned, | |
470 // entry point is in same cache line as unverified entry point, and the instruction being | |
471 // patched is >= 5 byte (size of patch). | |
472 // | |
473 // In C2 the 5+ byte sized instruction is enforced by code in MachPrologNode::emit. | |
474 // In C1 the restriction is enforced by CodeEmitter::method_entry | |
475 // | |
476 void NativeJump::patch_verified_entry(address entry, address verified_entry, address dest) { | |
477 // complete jump instruction (to be inserted) is in code_buffer; | |
478 unsigned char code_buffer[5]; | |
479 code_buffer[0] = instruction_code; | |
480 intptr_t disp = (intptr_t)dest - ((intptr_t)verified_entry + 1 + 4); | |
481 #ifdef AMD64 | |
482 guarantee(disp == (intptr_t)(int32_t)disp, "must be 32-bit offset"); | |
483 #endif // AMD64 | |
484 *(int32_t*)(code_buffer + 1) = (int32_t)disp; | |
485 | |
486 check_verified_entry_alignment(entry, verified_entry); | |
487 | |
488 // Can't call nativeJump_at() because it's asserts jump exists | |
489 NativeJump* n_jump = (NativeJump*) verified_entry; | |
490 | |
491 //First patch dummy jmp in place | |
492 | |
493 unsigned char patch[4]; | |
494 assert(sizeof(patch)==sizeof(int32_t), "sanity check"); | |
495 patch[0] = 0xEB; // jmp rel8 | |
496 patch[1] = 0xFE; // jmp to self | |
497 patch[2] = 0xEB; | |
498 patch[3] = 0xFE; | |
499 | |
500 // First patch dummy jmp in place | |
501 *(int32_t*)verified_entry = *(int32_t *)patch; | |
502 | |
503 n_jump->wrote(0); | |
504 | |
505 // Patch 5th byte (from jump instruction) | |
506 verified_entry[4] = code_buffer[4]; | |
507 | |
508 n_jump->wrote(4); | |
509 | |
510 // Patch bytes 0-3 (from jump instruction) | |
511 *(int32_t*)verified_entry = *(int32_t *)code_buffer; | |
512 // Invalidate. Opteron requires a flush after every write. | |
513 n_jump->wrote(0); | |
514 | |
515 } | |
516 | |
517 void NativePopReg::insert(address code_pos, Register reg) { | |
518 assert(reg->encoding() < 8, "no space for REX"); | |
519 assert(NativePopReg::instruction_size == sizeof(char), "right address unit for update"); | |
520 *code_pos = (u_char)(instruction_code | reg->encoding()); | |
521 ICache::invalidate_range(code_pos, instruction_size); | |
522 } | |
523 | |
524 | |
525 void NativeIllegalInstruction::insert(address code_pos) { | |
526 assert(NativeIllegalInstruction::instruction_size == sizeof(short), "right address unit for update"); | |
527 *(short *)code_pos = instruction_code; | |
528 ICache::invalidate_range(code_pos, instruction_size); | |
529 } | |
530 | |
531 void NativeGeneralJump::verify() { | |
532 assert(((NativeInstruction *)this)->is_jump() || | |
533 ((NativeInstruction *)this)->is_cond_jump(), "not a general jump instruction"); | |
534 } | |
535 | |
536 | |
537 void NativeGeneralJump::insert_unconditional(address code_pos, address entry) { | |
538 intptr_t disp = (intptr_t)entry - ((intptr_t)code_pos + 1 + 4); | |
539 #ifdef AMD64 | |
540 guarantee(disp == (intptr_t)(int32_t)disp, "must be 32-bit offset"); | |
541 #endif // AMD64 | |
542 | |
543 *code_pos = unconditional_long_jump; | |
544 *((int32_t *)(code_pos+1)) = (int32_t) disp; | |
545 ICache::invalidate_range(code_pos, instruction_size); | |
546 } | |
547 | |
548 | |
549 // MT-safe patching of a long jump instruction. | |
550 // First patches first word of instruction to two jmp's that jmps to them | |
551 // selfs (spinlock). Then patches the last byte, and then atomicly replaces | |
552 // the jmp's with the first 4 byte of the new instruction. | |
553 void NativeGeneralJump::replace_mt_safe(address instr_addr, address code_buffer) { | |
554 assert (instr_addr != NULL, "illegal address for code patching (4)"); | |
555 NativeGeneralJump* n_jump = nativeGeneralJump_at (instr_addr); // checking that it is a jump | |
556 | |
557 // Temporary code | |
558 unsigned char patch[4]; | |
559 assert(sizeof(patch)==sizeof(int32_t), "sanity check"); | |
560 patch[0] = 0xEB; // jmp rel8 | |
561 patch[1] = 0xFE; // jmp to self | |
562 patch[2] = 0xEB; | |
563 patch[3] = 0xFE; | |
564 | |
565 // First patch dummy jmp in place | |
566 *(int32_t*)instr_addr = *(int32_t *)patch; | |
567 n_jump->wrote(0); | |
568 | |
569 // Patch 4th byte | |
570 instr_addr[4] = code_buffer[4]; | |
571 | |
572 n_jump->wrote(4); | |
573 | |
574 // Patch bytes 0-3 | |
575 *(jint*)instr_addr = *(jint *)code_buffer; | |
576 | |
577 n_jump->wrote(0); | |
578 | |
579 #ifdef ASSERT | |
580 // verify patching | |
581 for ( int i = 0; i < instruction_size; i++) { | |
582 address ptr = (address)((intptr_t)code_buffer + i); | |
583 int a_byte = (*ptr) & 0xFF; | |
584 assert(*((address)((intptr_t)instr_addr + i)) == a_byte, "mt safe patching failed"); | |
585 } | |
586 #endif | |
587 | |
588 } | |
589 | |
590 | |
591 | |
592 address NativeGeneralJump::jump_destination() const { | |
593 int op_code = ubyte_at(0); | |
594 bool is_rel32off = (op_code == 0xE9 || op_code == 0x0F); | |
595 int offset = (op_code == 0x0F) ? 2 : 1; | |
596 int length = offset + ((is_rel32off) ? 4 : 1); | |
597 | |
598 if (is_rel32off) | |
599 return addr_at(0) + length + int_at(offset); | |
600 else | |
601 return addr_at(0) + length + sbyte_at(offset); | |
602 } | |
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603 |
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604 bool NativeInstruction::is_dtrace_trap() { |
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605 return (*(int32_t*)this & 0xff) == 0xcc; |
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606 } |