[vm/fuchsia] Make use of the new alignment flags when allocating memory.
Change-Id: I05994746156b35ad29d311461933359922de9959
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/105545
Reviewed-by: Zach Anderson <zra@google.com>
Commit-Queue: Régis Crelier <regis@google.com>
diff --git a/runtime/vm/virtual_memory.h b/runtime/vm/virtual_memory.h
index 496e63c..a91f07a 100644
--- a/runtime/vm/virtual_memory.h
+++ b/runtime/vm/virtual_memory.h
@@ -99,10 +99,6 @@
static uword page_size_;
-#if defined(HOST_OS_FUCHSIA)
- static uword base_; // Cached base of root vmar.
-#endif
-
DISALLOW_IMPLICIT_CONSTRUCTORS(VirtualMemory);
};
diff --git a/runtime/vm/virtual_memory_fuchsia.cc b/runtime/vm/virtual_memory_fuchsia.cc
index 3f934fd..91e9a78 100644
--- a/runtime/vm/virtual_memory_fuchsia.cc
+++ b/runtime/vm/virtual_memory_fuchsia.cc
@@ -39,22 +39,9 @@
DECLARE_FLAG(bool, write_protect_code);
uword VirtualMemory::page_size_ = 0;
-uword VirtualMemory::base_ = 0;
void VirtualMemory::Init() {
page_size_ = getpagesize();
-
- // Cache the base of zx_vmar_root_self() which is used to align mappings.
- zx_info_vmar_t buf[1];
- size_t actual;
- size_t avail;
- zx_status_t status =
- zx_object_get_info(zx_vmar_root_self(), ZX_INFO_VMAR, buf,
- sizeof(zx_info_vmar_t), &actual, &avail);
- if (status != ZX_OK) {
- FATAL1("zx_object_get_info failed: %s\n", zx_status_get_string(status));
- }
- base_ = buf[0].base;
}
static void Unmap(zx_handle_t vmar, uword start, uword end) {
@@ -70,48 +57,6 @@
}
}
-static void* MapAligned(zx_handle_t vmar,
- zx_handle_t vmo,
- zx_vm_option_t options,
- uword size,
- uword alignment,
- uword vmar_base,
- uword padded_size) {
- // Allocate a larger mapping than needed in order to find a suitable aligned
- // mapping within it.
- uword base;
- zx_status_t status =
- zx_vmar_map(vmar, options, 0, vmo, 0u, padded_size, &base);
- LOG_INFO("zx_vmar_map(%u, 0x%lx, 0x%lx)\n", options, base, padded_size);
- if (status != ZX_OK) {
- LOG_ERR("zx_vmar_map(%u, 0x%lx, 0x%lx) failed: %s\n", options, base,
- padded_size, zx_status_get_string(status));
- return NULL;
- }
-
- // Allocate a smaller aligned mapping inside the larger mapping.
- const uword orig_base = base;
- const uword aligned_base = Utils::RoundUp(base, alignment);
- const zx_vm_option_t overwrite_options = options | ZX_VM_SPECIFIC_OVERWRITE;
- status = zx_vmar_map(vmar, overwrite_options, aligned_base - vmar_base, vmo,
- 0u, size, &base);
- LOG_INFO("zx_vmar_map(%u, 0x%lx, 0x%lx)\n", overwrite_options,
- aligned_base - vmar_base, size);
-
- if (status != ZX_OK) {
- LOG_ERR("zx_vmar_map(%u, 0x%lx, 0x%lx) failed: %s\n", overwrite_options,
- aligned_base - vmar_base, size, zx_status_get_string(status));
- return NULL;
- }
- ASSERT(base == aligned_base);
-
- // Unmap the unused prefix and suffix.
- Unmap(vmar, orig_base, base);
- Unmap(vmar, base + size, orig_base + padded_size);
-
- return reinterpret_cast<void*>(base);
-}
-
VirtualMemory* VirtualMemory::AllocateAligned(intptr_t size,
intptr_t alignment,
bool is_executable,
@@ -127,7 +72,10 @@
ASSERT(Utils::IsAligned(size, page_size_));
ASSERT(Utils::IsPowerOfTwo(alignment));
ASSERT(Utils::IsAligned(alignment, page_size_));
- const intptr_t padded_size = size + 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));
zx_handle_t vmar = zx_vmar_root_self();
zx_handle_t vmo = ZX_HANDLE_INVALID;
@@ -154,27 +102,34 @@
}
const zx_vm_option_t region_options =
- ZX_VM_PERM_READ | ZX_VM_PERM_WRITE |
+ ZX_VM_PERM_READ | ZX_VM_PERM_WRITE | align_flag |
((is_executable && !FLAG_write_protect_code) ? ZX_VM_PERM_EXECUTE : 0);
- void* region_ptr = MapAligned(vmar, vmo, region_options, size, alignment,
- base_, padded_size);
- if (region_ptr == NULL) {
+ 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) {
// ZX_VM_PERM_EXECUTE is added later via VirtualMemory::Protect.
- const zx_vm_option_t alias_options = ZX_VM_PERM_READ;
- void* alias_ptr = MapAligned(vmar, vmo, alias_options, size, alignment,
- base_, padded_size);
- if (alias_ptr == NULL) {
+ const zx_vm_option_t alias_options = ZX_VM_PERM_READ | 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);
