1 /*
  2  * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
  3  * Copyright (c) 2018, SAP SE. 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 "precompiled.hpp"
 27 #include "asm/macroAssembler.inline.hpp"
 28 #include "gc/shared/barrierSet.hpp"
 29 #include "gc/shared/cardTable.hpp"
 30 #include "gc/shared/cardTableBarrierSet.hpp"
 31 #include "gc/shared/cardTableBarrierSetAssembler.hpp"
 32 #include "gc/shared/collectedHeap.hpp"
 33 #include "interpreter/interp_masm.hpp"
 34 
 35 #define __ masm->
 36 
 37 #ifdef PRODUCT
 38 #define BLOCK_COMMENT(str) /* nothing */
 39 #else
 40 #define BLOCK_COMMENT(str) __ block_comment(str)
 41 #endif
 42 
 43 #define BIND(label) bind(label); BLOCK_COMMENT(#label ":")
 44 
 45 #define TIMES_OOP (UseCompressedOops ? Address::times_4 : Address::times_8)
 46 
 47 void CardTableBarrierSetAssembler::gen_write_ref_array_post_barrier(MacroAssembler* masm, DecoratorSet decorators, Register addr, Register count,
 48                                                                     bool do_return) {
 49   CardTableBarrierSet* ctbs = barrier_set_cast<CardTableBarrierSet>(Universe::heap()->barrier_set());
 50   CardTable* ct = ctbs->card_table();
 51   assert(sizeof(*ct->byte_map_base()) == sizeof(jbyte), "adjust this code");
 52 
 53   NearLabel doXC, done;
 54   assert_different_registers(Z_R0, Z_R1, addr, count);
 55 
 56   // Nothing to do if count <= 0.
 57   if (!do_return) {
 58     __ compare64_and_branch(count, (intptr_t) 0, Assembler::bcondNotHigh, done);
 59   } else {
 60     __ z_ltgr(count, count);
 61     __ z_bcr(Assembler::bcondNotPositive, Z_R14);
 62   }
 63 
 64   // Note: We can't combine the shifts. We could lose a carry
 65   // from calculating the array end address.
 66   // count = (count-1)*BytesPerHeapOop + addr
 67   // Count holds addr of last oop in array then.
 68   __ z_sllg(count, count, LogBytesPerHeapOop);
 69   __ add2reg_with_index(count, -BytesPerHeapOop, count, addr);
 70 
 71   // Get base address of card table.
 72   __ load_const_optimized(Z_R1, (address)ct->byte_map_base());
 73 
 74   // count = (count>>shift) - (addr>>shift)
 75   __ z_srlg(addr,  addr,  CardTable::card_shift);
 76   __ z_srlg(count, count, CardTable::card_shift);
 77 
 78   // Prefetch first elements of card table for update.
 79   if (VM_Version::has_Prefetch()) {
 80     __ z_pfd(0x02, 0, addr, Z_R1);
 81   }
 82 
 83   // Special case: clear just one byte.
 84   __ clear_reg(Z_R0, true, false);  // Used for doOneByte.
 85   __ z_sgr(count, addr);            // Count = n-1 now, CC used for brc below.
 86   __ z_stc(Z_R0, 0, addr, Z_R1);    // Must preserve CC from z_sgr.
 87   if (!do_return) {
 88     __ z_brz(done);
 89   } else {
 90     __ z_bcr(Assembler::bcondZero, Z_R14);
 91   }
 92 
 93   __ z_cghi(count, 255);
 94   __ z_brnh(doXC);
 95 
 96   // MVCLE: clear a long area.
 97   // Start addr of card table range = base + addr.
 98   // # bytes in    card table range = (count + 1)
 99   __ add2reg_with_index(Z_R0, 0, Z_R1, addr);
100   __ add2reg(Z_R1, 1, count);
101 
102   // dirty hack:
103   // There are just two callers. Both pass
104   // count in Z_ARG3 = Z_R4
105   // addr  in Z_ARG2 = Z_R3
106   // ==> use Z_ARG2 as src len reg = 0
107   //         Z_ARG1 as src addr (ignored)
108   assert(count == Z_ARG3, "count: unexpected register number");
109   assert(addr  == Z_ARG2, "addr:  unexpected register number");
110   __ clear_reg(Z_ARG2, true, false);
111 
112   __ MacroAssembler::move_long_ext(Z_R0, Z_ARG1, 0);
113 
114   if (!do_return) {
115     __ z_bru(done);
116   } else {
117     __ z_bcr(Assembler::bcondAlways, Z_R14);
118   }
119 
120   // XC: clear a short area.
121   Label XC_template; // Instr template, never exec directly!
122   __ bind(XC_template);
123   __ z_xc(0, 0, addr, 0, addr);
124 
125   __ bind(doXC);
126   // start addr of card table range = base + addr
127   // end   addr of card table range = base + addr + count
128   __ add2reg_with_index(addr, 0, Z_R1, addr);
129 
130   if (VM_Version::has_ExecuteExtensions()) {
131     __ z_exrl(count, XC_template);   // Execute XC with var. len.
132   } else {
133     __ z_larl(Z_R1, XC_template);
134     __ z_ex(count, 0, Z_R0, Z_R1);   // Execute XC with var. len.
135   }
136   if (do_return) {
137     __ z_br(Z_R14);
138   }
139 
140   __ bind(done);
141 }