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const std = @import("std");
const mem = std.mem;
const uefi = std.os.uefi;
const assert = std.debug.assert;
const Allocator = mem.Allocator;
const UefiPoolAllocator = struct {
fn getHeader(ptr: [*]u8) *[*]align(8) u8 {
return @as(*[*]align(8) u8, @ptrFromInt(@intFromPtr(ptr) - @sizeOf(usize)));
}
fn alloc(
_: *anyopaque,
len: usize,
alignment: mem.Alignment,
ret_addr: usize,
) ?[*]u8 {
_ = ret_addr;
assert(len > 0);
const ptr_align = alignment.toByteUnits();
const metadata_len = mem.alignForward(usize, @sizeOf(usize), ptr_align);
const full_len = metadata_len + len;
const unaligned_slice = uefi.system_table.boot_services.?.allocatePool(
uefi.efi_pool_memory_type,
full_len,
) catch return null;
const unaligned_addr = @intFromPtr(unaligned_slice.ptr);
const aligned_addr = mem.alignForward(usize, unaligned_addr + @sizeOf(usize), ptr_align);
const aligned_ptr = unaligned_slice.ptr + (aligned_addr - unaligned_addr);
getHeader(aligned_ptr).* = unaligned_slice.ptr;
return aligned_ptr;
}
fn resize(
_: *anyopaque,
buf: []u8,
alignment: mem.Alignment,
new_len: usize,
ret_addr: usize,
) bool {
_ = ret_addr;
_ = alignment;
if (new_len > buf.len) return false;
return true;
}
fn remap(
_: *anyopaque,
buf: []u8,
alignment: mem.Alignment,
new_len: usize,
ret_addr: usize,
) ?[*]u8 {
_ = alignment;
_ = ret_addr;
if (new_len > buf.len) return null;
return buf.ptr;
}
fn free(
_: *anyopaque,
buf: []u8,
alignment: mem.Alignment,
ret_addr: usize,
) void {
_ = alignment;
_ = ret_addr;
uefi.system_table.boot_services.?.freePool(getHeader(buf.ptr).*) catch unreachable;
}
};
/// Supports the full Allocator interface, including alignment.
/// For a direct call of `allocatePool`, see `raw_pool_allocator`.
pub const pool_allocator = Allocator{
.ptr = undefined,
.vtable = &pool_allocator_vtable,
};
const pool_allocator_vtable = Allocator.VTable{
.alloc = UefiPoolAllocator.alloc,
.resize = UefiPoolAllocator.resize,
.remap = UefiPoolAllocator.remap,
.free = UefiPoolAllocator.free,
};
/// Asserts allocations are 8 byte aligned and calls `boot_services.allocatePool`.
pub const raw_pool_allocator = Allocator{
.ptr = undefined,
.vtable = &raw_pool_allocator_table,
};
const raw_pool_allocator_table = Allocator.VTable{
.alloc = uefi_alloc,
.resize = uefi_resize,
.remap = uefi_remap,
.free = uefi_free,
};
fn uefi_alloc(
_: *anyopaque,
len: usize,
alignment: mem.Alignment,
ret_addr: usize,
) ?[*]u8 {
_ = ret_addr;
std.debug.assert(@intFromEnum(alignment) <= 3);
const slice = uefi.system_table.boot_services.?.allocatePool(
uefi.efi_pool_memory_type,
len,
) catch return null;
return slice.ptr;
}
fn uefi_resize(
_: *anyopaque,
buf: []u8,
alignment: mem.Alignment,
new_len: usize,
ret_addr: usize,
) bool {
_ = ret_addr;
std.debug.assert(@intFromEnum(alignment) <= 3);
if (new_len > buf.len) return false;
return true;
}
fn uefi_remap(
_: *anyopaque,
buf: []u8,
alignment: mem.Alignment,
new_len: usize,
ret_addr: usize,
) ?[*]u8 {
_ = ret_addr;
std.debug.assert(@intFromEnum(alignment) <= 3);
if (new_len > buf.len) return null;
return buf.ptr;
}
fn uefi_free(
_: *anyopaque,
buf: []u8,
alignment: mem.Alignment,
ret_addr: usize,
) void {
_ = alignment;
_ = ret_addr;
uefi.system_table.boot_services.?.freePool(@alignCast(buf.ptr)) catch unreachable;
}
|
