| /* |
| * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #include "precompiled.hpp" |
| #include "logging/log.hpp" |
| #include "runtime/globals.hpp" |
| #include "runtime/os.hpp" |
| #include "runtime/safepointMechanism.hpp" |
| #include "services/memTracker.hpp" |
| #include <sys/mman.h> |
| |
| void SafepointMechanism::pd_initialize() { |
| // No special code needed if we can use SIGTRAP |
| if (ThreadLocalHandshakes && USE_POLL_BIT_ONLY) { |
| default_initialize(); |
| return; |
| } |
| |
| // Allocate one protected page |
| char* map_address = (char*)MAP_FAILED; |
| const size_t map_size = ThreadLocalHandshakes ? 2 * os::vm_page_size() : os::vm_page_size(); |
| const int prot = PROT_READ; |
| const int flags = MAP_PRIVATE | MAP_ANONYMOUS; |
| |
| // Use optimized addresses for the polling page, |
| // e.g. map it to a special 32-bit address. |
| if (OptimizePollingPageLocation) { |
| // architecture-specific list of address wishes: |
| char* address_wishes[] = { |
| // AIX: addresses lower than 0x30000000 don't seem to work on AIX. |
| // PPC64: all address wishes are non-negative 32 bit values where |
| // the lower 16 bits are all zero. we can load these addresses |
| // with a single ppc_lis instruction. |
| (char*) 0x30000000, (char*) 0x31000000, |
| (char*) 0x32000000, (char*) 0x33000000, |
| (char*) 0x40000000, (char*) 0x41000000, |
| (char*) 0x42000000, (char*) 0x43000000, |
| (char*) 0x50000000, (char*) 0x51000000, |
| (char*) 0x52000000, (char*) 0x53000000, |
| (char*) 0x60000000, (char*) 0x61000000, |
| (char*) 0x62000000, (char*) 0x63000000 |
| }; |
| int address_wishes_length = sizeof(address_wishes)/sizeof(char*); |
| |
| // iterate over the list of address wishes: |
| for (int i = 0; i < address_wishes_length; i++) { |
| // Try to map with current address wish. |
| // AIX: AIX needs MAP_FIXED if we provide an address and mmap will |
| // fail if the address is already mapped. |
| map_address = (char*) ::mmap(address_wishes[i], |
| map_size, prot, |
| flags | MAP_FIXED, |
| -1, 0); |
| log_debug(os)("SafePoint Polling Page address: %p (wish) => %p", |
| address_wishes[i], map_address); |
| |
| if (map_address == address_wishes[i]) { |
| // Map succeeded and map_address is at wished address, exit loop. |
| break; |
| } |
| |
| if (map_address != (char*)MAP_FAILED) { |
| // Map succeeded, but polling_page is not at wished address, unmap and continue. |
| ::munmap(map_address, map_size); |
| map_address = (char*)MAP_FAILED; |
| } |
| // Map failed, continue loop. |
| } |
| } |
| if (map_address == (char*)MAP_FAILED) { |
| map_address = (char*) ::mmap(NULL, map_size, prot, flags, -1, 0); |
| } |
| guarantee(map_address != (char*)MAP_FAILED && map_address != NULL, |
| "SafepointMechanism::pd_initialize: failed to allocate polling page"); |
| log_info(os)("SafePoint Polling address: " INTPTR_FORMAT, p2i(map_address)); |
| os::set_polling_page((address)(map_address)); |
| |
| // Register polling page with NMT. |
| MemTracker::record_virtual_memory_reserve_and_commit(map_address, map_size, CALLER_PC, mtSafepoint); |
| |
| // Use same page for ThreadLocalHandshakes without SIGTRAP |
| if (ThreadLocalHandshakes) { |
| set_uses_thread_local_poll(); |
| os::make_polling_page_unreadable(); |
| intptr_t bad_page_val = reinterpret_cast<intptr_t>(map_address), |
| good_page_val = bad_page_val + os::vm_page_size(); |
| _poll_armed_value = reinterpret_cast<void*>(bad_page_val + poll_bit()); |
| _poll_disarmed_value = reinterpret_cast<void*>(good_page_val); |
| } |
| } |