blob: 7f7347d98775a82d911600904452a66f4ae4e3cd [file] [log] [blame]
// Copyright (c) 2016, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#include "vm/globals.h"
#if defined(DART_HOST_OS_FUCHSIA)
#include "vm/virtual_memory.h"
#include <sys/mman.h>
#include <unistd.h>
#include <zircon/process.h>
#include <zircon/status.h>
#include <zircon/syscalls.h>
#include "platform/assert.h"
#include "vm/allocation.h"
#include "vm/growable_array.h"
#include "vm/isolate.h"
#include "vm/lockers.h"
#include "vm/memory_region.h"
#include "vm/os.h"
#include "vm/os_thread.h"
#include "vm/virtual_memory_compressed.h"
// #define VIRTUAL_MEMORY_LOGGING 1
#if defined(VIRTUAL_MEMORY_LOGGING)
#define LOG_ERR(msg, ...) \
OS::PrintErr("VMVM: %s:%d: " msg, __FILE__, __LINE__, ##__VA_ARGS__)
#define LOG_INFO(msg, ...) \
OS::PrintErr("VMVM: %s:%d: " msg, __FILE__, __LINE__, ##__VA_ARGS__)
#else
#define LOG_ERR(msg, ...)
#define LOG_INFO(msg, ...)
#endif // defined(VIRTUAL_MEMORY_LOGGING)
namespace dart {
DECLARE_FLAG(bool, dual_map_code);
DECLARE_FLAG(bool, write_protect_code);
uword VirtualMemory::page_size_ = 0;
#if defined(DART_COMPRESSED_POINTERS)
static zx_handle_t compressed_heap_vmar_ = ZX_HANDLE_INVALID;
static uword compressed_heap_base_ = 0;
#endif // defined(DART_COMPRESSED_POINTERS)
intptr_t VirtualMemory::CalculatePageSize() {
const intptr_t page_size = getpagesize();
ASSERT(page_size != 0);
ASSERT(Utils::IsPowerOfTwo(page_size));
return page_size;
}
void VirtualMemory::Init() {
#if defined(DART_COMPRESSED_POINTERS)
if (compressed_heap_vmar_ == ZX_HANDLE_INVALID) {
const zx_vm_option_t align_flag =
Utils::ShiftForPowerOfTwo(kCompressedHeapAlignment) << ZX_VM_ALIGN_BASE;
const zx_vm_option_t options = ZX_VM_CAN_MAP_READ | ZX_VM_CAN_MAP_WRITE |
ZX_VM_CAN_MAP_SPECIFIC | align_flag;
zx_vaddr_t region;
zx_status_t status =
zx_vmar_allocate(zx_vmar_root_self(), options, 0, kCompressedHeapSize,
&compressed_heap_vmar_, &region);
if (status != ZX_OK) {
LOG_ERR("zx_vmar_allocate(0x%lx) failed: %s\n", kCompressedHeapSize,
zx_status_get_string(status));
} else {
compressed_heap_base_ = reinterpret_cast<uword>(region);
ASSERT(Utils::IsAligned(compressed_heap_base_, kCompressedHeapAlignment));
}
}
#endif // defined(DART_COMPRESSED_POINTERS)
page_size_ = CalculatePageSize();
}
void VirtualMemory::Cleanup() {
#if defined(DART_COMPRESSED_POINTERS)
zx_vmar_destroy(compressed_heap_vmar_);
compressed_heap_vmar_ = ZX_HANDLE_INVALID;
compressed_heap_base_ = 0;
#endif // defined(DART_COMPRESSED_POINTERS)
}
static zx_handle_t getVmarForAddress(uword address) {
#if defined(DART_COMPRESSED_POINTERS)
if (address - compressed_heap_base_ < kCompressedHeapSize) {
return compressed_heap_vmar_;
}
#endif // defined(DART_COMPRESSED_POINTERS)
return zx_vmar_root_self();
}
static void Unmap(zx_handle_t vmar, uword start, uword end) {
ASSERT(start <= end);
const uword size = end - start;
if (size == 0) {
return;
}
zx_status_t status = zx_vmar_unmap(vmar, start, size);
if (status != ZX_OK) {
FATAL1("zx_vmar_unmap failed: %s\n", zx_status_get_string(status));
}
}
bool VirtualMemory::DualMappingEnabled() {
return FLAG_dual_map_code;
}
VirtualMemory* VirtualMemory::AllocateAligned(intptr_t size,
intptr_t alignment,
bool is_executable,
const char* name) {
// When FLAG_write_protect_code is active, code memory (indicated by
// is_executable = true) is allocated as non-executable and later
// changed to executable via VirtualMemory::Protect, which requires
// ZX_RIGHT_EXECUTE on the underlying VMO.
//
// If FLAG_dual_map_code is active, the executable mapping will be mapped RX
// immediately and never changes protection until it is eventually unmapped.
//
// In addition, dual mapping of the same underlying code memory is provided.
const bool dual_mapping =
is_executable && FLAG_write_protect_code && FLAG_dual_map_code;
ASSERT(Utils::IsAligned(size, page_size_));
ASSERT(Utils::IsPowerOfTwo(alignment));
ASSERT(Utils::IsAligned(alignment, page_size_));
const zx_vm_option_t align_flag = Utils::ShiftForPowerOfTwo(alignment)
<< ZX_VM_ALIGN_BASE;
ASSERT((ZX_VM_ALIGN_1KB <= align_flag) && (align_flag <= ZX_VM_ALIGN_4GB));
#if defined(DART_COMPRESSED_POINTERS)
zx_handle_t vmar =
is_executable ? zx_vmar_root_self() : compressed_heap_vmar_;
#else
zx_handle_t vmar = zx_vmar_root_self();
#endif // defined(DART_COMPRESSED_POINTERS)
zx_handle_t vmo = ZX_HANDLE_INVALID;
zx_status_t status = zx_vmo_create(size, 0u, &vmo);
if (status != ZX_OK) {
LOG_ERR("zx_vmo_create(0x%lx) failed: %s\n", size,
zx_status_get_string(status));
return NULL;
}
if (name != NULL) {
zx_object_set_property(vmo, ZX_PROP_NAME, name, strlen(name));
}
if (is_executable) {
// Add ZX_RIGHT_EXECUTE permission to VMO, so it can be mapped
// into memory as executable (now or later).
status = zx_vmo_replace_as_executable(vmo, ZX_HANDLE_INVALID, &vmo);
if (status != ZX_OK) {
LOG_ERR("zx_vmo_replace_as_executable() failed: %s\n",
zx_status_get_string(status));
return NULL;
}
}
const zx_vm_option_t region_options =
ZX_VM_PERM_READ | ZX_VM_PERM_WRITE | align_flag |
((is_executable && !FLAG_write_protect_code) ? ZX_VM_PERM_EXECUTE : 0);
uword base;
status = zx_vmar_map(vmar, region_options, 0, vmo, 0u, size, &base);
LOG_INFO("zx_vmar_map(%u, 0x%lx, 0x%lx)\n", region_options, base, size);
if (status != ZX_OK) {
LOG_ERR("zx_vmar_map(%u, 0x%lx, 0x%lx) failed: %s\n", region_options, base,
size, zx_status_get_string(status));
return NULL;
}
void* region_ptr = reinterpret_cast<void*>(base);
MemoryRegion region(region_ptr, size);
VirtualMemory* result;
if (dual_mapping) {
// The mapping will be RX and stays that way until it will eventually be
// unmapped.
const zx_vm_option_t alias_options =
ZX_VM_PERM_READ | ZX_VM_PERM_EXECUTE | align_flag;
status = zx_vmar_map(vmar, alias_options, 0, vmo, 0u, size, &base);
LOG_INFO("zx_vmar_map(%u, 0x%lx, 0x%lx)\n", alias_options, base, size);
if (status != ZX_OK) {
LOG_ERR("zx_vmar_map(%u, 0x%lx, 0x%lx) failed: %s\n", alias_options, base,
size, zx_status_get_string(status));
const uword region_base = reinterpret_cast<uword>(region_ptr);
Unmap(vmar, region_base, region_base + size);
return NULL;
}
void* alias_ptr = reinterpret_cast<void*>(base);
ASSERT(region_ptr != alias_ptr);
MemoryRegion alias(alias_ptr, size);
result = new VirtualMemory(region, alias, region);
} else {
result = new VirtualMemory(region, region, region);
}
zx_handle_close(vmo);
#if defined(DART_COMPRESSED_POINTERS)
if (!is_executable) {
uword offset = result->start() - compressed_heap_base_;
ASSERT(offset < kCompressedHeapSize);
}
#endif // defined(DART_COMPRESSED_POINTERS)
return result;
}
VirtualMemory::~VirtualMemory() {
// Reserved region may be empty due to VirtualMemory::Truncate.
if (vm_owns_region() && reserved_.size() != 0) {
Unmap(getVmarForAddress(reserved_.start()), reserved_.start(),
reserved_.end());
LOG_INFO("zx_vmar_unmap(0x%lx, 0x%lx) success\n", reserved_.start(),
reserved_.size());
const intptr_t alias_offset = AliasOffset();
if (alias_offset != 0) {
Unmap(getVmarForAddress(reserved_.start()),
reserved_.start() + alias_offset, reserved_.end() + alias_offset);
LOG_INFO("zx_vmar_unmap(0x%lx, 0x%lx) success\n",
reserved_.start() + alias_offset, reserved_.size());
}
}
}
bool VirtualMemory::FreeSubSegment(void* address, intptr_t size) {
const uword start = reinterpret_cast<uword>(address);
Unmap(getVmarForAddress(start), start, start + size);
LOG_INFO("zx_vmar_unmap(0x%p, 0x%lx) success\n", address, size);
return true;
}
void VirtualMemory::Protect(void* address, intptr_t size, Protection mode) {
#if defined(DEBUG)
Thread* thread = Thread::Current();
ASSERT(thread == nullptr || thread->IsMutatorThread() ||
thread->isolate() == nullptr ||
thread->isolate()->mutator_thread()->IsAtSafepoint());
#endif
const uword start_address = reinterpret_cast<uword>(address);
const uword end_address = start_address + size;
const uword page_address = Utils::RoundDown(start_address, PageSize());
uint32_t prot = 0;
switch (mode) {
case kNoAccess:
prot = 0;
break;
case kReadOnly:
prot = ZX_VM_PERM_READ;
break;
case kReadWrite:
prot = ZX_VM_PERM_READ | ZX_VM_PERM_WRITE;
break;
case kReadExecute:
prot = ZX_VM_PERM_READ | ZX_VM_PERM_EXECUTE;
break;
case kReadWriteExecute:
prot = ZX_VM_PERM_READ | ZX_VM_PERM_WRITE | ZX_VM_PERM_EXECUTE;
break;
}
zx_status_t status =
zx_vmar_protect(getVmarForAddress(page_address), prot, page_address,
end_address - page_address);
LOG_INFO("zx_vmar_protect(%u, 0x%lx, 0x%lx)\n", prot, page_address,
end_address - page_address);
if (status != ZX_OK) {
FATAL3("zx_vmar_protect(0x%lx, 0x%lx) failed: %s\n", page_address,
end_address - page_address, zx_status_get_string(status));
}
}
} // namespace dart
#endif // defined(DART_HOST_OS_FUCHSIA)