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// Copyright (c) 2021, 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 "platform/globals.h"
#if defined(DART_HOST_OS_FUCHSIA)
#include "bin/virtual_memory.h"
#include <zircon/process.h>
#include <zircon/status.h>
#include <zircon/syscalls.h>
#include "platform/assert.h"
#include "platform/utils.h"
namespace dart {
namespace bin {
uword VirtualMemory::page_size_ = 0;
intptr_t VirtualMemory::CalculatePageSize() {
const intptr_t page_size = getpagesize();
ASSERT(page_size != 0);
ASSERT(Utils::IsPowerOfTwo(page_size));
return page_size;
}
VirtualMemory* VirtualMemory::Allocate(intptr_t size,
bool is_executable,
const char* name) {
ASSERT(Utils::IsAligned(size, page_size_));
zx_handle_t vmar = zx_vmar_root_self();
zx_handle_t vmo = ZX_HANDLE_INVALID;
zx_status_t status = zx_vmo_create(size, 0u, &vmo);
if (status != ZX_OK) {
return nullptr;
}
if (name != nullptr) {
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) {
zx_handle_close(vmo);
return nullptr;
}
}
const zx_vm_option_t region_options =
ZX_VM_PERM_READ | ZX_VM_PERM_WRITE |
(is_executable ? ZX_VM_PERM_EXECUTE : 0);
uword base;
status = zx_vmar_map(vmar, region_options, 0, vmo, 0u, size, &base);
zx_handle_close(vmo);
if (status != ZX_OK) {
return nullptr;
}
return new VirtualMemory(reinterpret_cast<void*>(base), size);
}
VirtualMemory::~VirtualMemory() {
if (address_ != nullptr) {
zx_status_t status = zx_vmar_unmap(
zx_vmar_root_self(), reinterpret_cast<uword>(address_), size_);
if (status != ZX_OK) {
FATAL("zx_vmar_unmap failed: %s\n", zx_status_get_string(status));
}
}
}
void VirtualMemory::Protect(void* address, intptr_t size, Protection mode) {
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(zx_vmar_root_self(), prot, page_address,
end_address - page_address);
if (status != ZX_OK) {
FATAL("zx_vmar_protect(0x%lx, 0x%lx) failed: %s\n", page_address,
end_address - page_address, zx_status_get_string(status));
}
}
} // namespace bin
} // namespace dart
#endif // defined(DART_HOST_OS_FUCHSIA)