1 /*
2 * Copyright (c) 2019, 2020, Oracle and/or its affiliates. All rights reserved.
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 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24 #include "precompiled.hpp"
25 #include "gc/z/zErrno.hpp"
26 #include "gc/z/zGlobals.hpp"
27 #include "gc/z/zLargePages.inline.hpp"
28 #include "gc/z/zPhysicalMemory.inline.hpp"
29 #include "gc/z/zPhysicalMemoryBacking_bsd.hpp"
30 #include "logging/log.hpp"
31 #include "runtime/globals.hpp"
32 #include "runtime/os.hpp"
33 #include "utilities/align.hpp"
34 #include "utilities/debug.hpp"
35
36 #include <mach/mach.h>
37 #include <mach/mach_vm.h>
38 #include <sys/mman.h>
39 #include <sys/types.h>
40
41 // The backing is represented by a reserved virtual address space, in which
42 // we commit and uncommit physical memory. Multi-mapping the different heap
43 // views is done by simply remapping the backing memory using mach_vm_remap().
44
45 static int vm_flags_superpage() {
46 if (!ZLargePages::is_explicit()) {
47 return 0;
48 }
49
50 const int page_size_in_megabytes = ZGranuleSize >> 20;
51 return page_size_in_megabytes << VM_FLAGS_SUPERPAGE_SHIFT;
52 }
53
54 static ZErrno mremap(uintptr_t from_addr, uintptr_t to_addr, size_t size) {
55 mach_vm_address_t remap_addr = to_addr;
56 vm_prot_t remap_cur_prot;
57 vm_prot_t remap_max_prot;
58
59 // Remap memory to an additional location
60 const kern_return_t res = mach_vm_remap(mach_task_self(),
61 &remap_addr,
62 size,
63 0 /* mask */,
64 VM_FLAGS_FIXED | VM_FLAGS_OVERWRITE | vm_flags_superpage(),
65 mach_task_self(),
66 from_addr,
67 FALSE /* copy */,
68 &remap_cur_prot,
69 &remap_max_prot,
70 VM_INHERIT_COPY);
71
72 return (res == KERN_SUCCESS) ? ZErrno(0) : ZErrno(EINVAL);
73 }
74
75 ZPhysicalMemoryBacking::ZPhysicalMemoryBacking(size_t max_capacity) :
76 _base(0),
77 _initialized(false) {
78
79 // Reserve address space for backing memory
80 _base = (uintptr_t)os::reserve_memory(max_capacity);
81 if (_base == 0) {
82 // Failed
83 log_error(gc)("Failed to reserve address space for backing memory");
84 return;
85 }
86
87 // Successfully initialized
88 _initialized = true;
89 }
90
91 bool ZPhysicalMemoryBacking::is_initialized() const {
92 return _initialized;
93 }
94
95 void ZPhysicalMemoryBacking::warn_commit_limits(size_t max) const {
96 // Does nothing
97 }
98
99 bool ZPhysicalMemoryBacking::commit_inner(size_t offset, size_t length) {
100 assert(is_aligned(offset, os::vm_page_size()), "Invalid offset");
101 assert(is_aligned(length, os::vm_page_size()), "Invalid length");
102
103 log_trace(gc, heap)("Committing memory: " SIZE_FORMAT "M-" SIZE_FORMAT "M (" SIZE_FORMAT "M)",
104 offset / M, (offset + length) / M, length / M);
105
106 const uintptr_t addr = _base + offset;
107 const void* const res = mmap((void*)addr, length, PROT_READ | PROT_WRITE, MAP_FIXED | MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
108 if (res == MAP_FAILED) {
109 ZErrno err;
110 log_error(gc)("Failed to commit memory (%s)", err.to_string());
111 return false;
112 }
113
114 // Success
115 return true;
116 }
117
118 size_t ZPhysicalMemoryBacking::commit(size_t offset, size_t length) {
119 // Try to commit the whole region
120 if (commit_inner(offset, length)) {
121 // Success
122 return length;
123 }
124
125 // Failed, try to commit as much as possible
126 size_t start = offset;
127 size_t end = offset + length;
128
129 for (;;) {
130 length = align_down((end - start) / 2, ZGranuleSize);
131 if (length == 0) {
132 // Done, don't commit more
133 return start - offset;
134 }
135
136 if (commit_inner(start, length)) {
137 // Success, try commit more
138 start += length;
139 } else {
140 // Failed, try commit less
141 end -= length;
142 }
143 }
144 }
145
146 size_t ZPhysicalMemoryBacking::uncommit(size_t offset, size_t length) {
147 assert(is_aligned(offset, os::vm_page_size()), "Invalid offset");
148 assert(is_aligned(length, os::vm_page_size()), "Invalid length");
149
150 log_trace(gc, heap)("Uncommitting memory: " SIZE_FORMAT "M-" SIZE_FORMAT "M (" SIZE_FORMAT "M)",
151 offset / M, (offset + length) / M, length / M);
152
153 const uintptr_t start = _base + offset;
154 const void* const res = mmap((void*)start, length, PROT_NONE, MAP_FIXED | MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE, -1, 0);
155 if (res == MAP_FAILED) {
156 ZErrno err;
157 log_error(gc)("Failed to uncommit memory (%s)", err.to_string());
158 return 0;
159 }
160
161 return length;
162 }
163
164 void ZPhysicalMemoryBacking::map(uintptr_t addr, size_t size, uintptr_t offset) const {
165 const ZErrno err = mremap(_base + offset, addr, size);
166 if (err) {
167 fatal("Failed to remap memory (%s)", err.to_string());
168 }
169 }
170
171 void ZPhysicalMemoryBacking::unmap(uintptr_t addr, size_t size) const {
172 // Note that we must keep the address space reservation intact and just detach
173 // the backing memory. For this reason we map a new anonymous, non-accessible
174 // and non-reserved page over the mapping instead of actually unmapping.
175 const void* const res = mmap((void*)addr, size, PROT_NONE, MAP_FIXED | MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE, -1, 0);
176 if (res == MAP_FAILED) {
177 ZErrno err;
178 fatal("Failed to map memory (%s)", err.to_string());
179 }
180 }