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 @intToPtr(*[*]align(8) u8, @ptrToInt(ptr) - @sizeOf(usize));
}
fn alloc(
_: *anyopaque,
len: usize,
log2_ptr_align: u8,
ret_addr: usize,
) ?[*]u8 {
_ = ret_addr;
assert(len > 0);
const ptr_align = @as(usize, 1) << @intCast(Allocator.Log2Align, log2_ptr_align);
const metadata_len = mem.alignForward(@sizeOf(usize), ptr_align);
const full_len = metadata_len + len;
var unaligned_ptr: [*]align(8) u8 = undefined;
if (uefi.system_table.boot_services.?.allocatePool(uefi.efi_pool_memory_type, full_len, &unaligned_ptr) != .Success) return null;
const unaligned_addr = @ptrToInt(unaligned_ptr);
const aligned_addr = mem.alignForward(unaligned_addr + @sizeOf(usize), ptr_align);
var aligned_ptr = unaligned_ptr + (aligned_addr - unaligned_addr);
getHeader(aligned_ptr).* = unaligned_ptr;
return aligned_ptr;
}
fn resize(
_: *anyopaque,
buf: []u8,
log2_old_ptr_align: u8,
new_len: usize,
ret_addr: usize,
) bool {
_ = ret_addr;
if (new_len > buf.len) return false;
_ = mem.alignAllocLen(buf.len, new_len, log2_old_ptr_align);
return true;
}
fn free(
_: *anyopaque,
buf: []u8,
log2_old_ptr_align: u8,
ret_addr: usize,
) void {
_ = log2_old_ptr_align;
_ = ret_addr;
_ = uefi.system_table.boot_services.?.freePool(getHeader(buf.ptr).*);
}
};
pub const pool_allocator = Allocator{
.ptr = undefined,
.vtable = &pool_allocator_vtable,
};
const pool_allocator_vtable = Allocator.VTable{
.alloc = UefiPoolAllocator.alloc,
.resize = UefiPoolAllocator.resize,
.free = UefiPoolAllocator.free,
};
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,
.free = uefi_free,
};
fn uefi_alloc(
_: *anyopaque,
len: usize,
log2_ptr_align: u8,
ret_addr: usize,
) ?[*]u8 {
_ = ret_addr;
std.debug.assert(log2_ptr_align <= 3);
var ptr: [*]align(8) u8 = undefined;
if (uefi.system_table.boot_services.?.allocatePool(uefi.efi_pool_memory_type, len, &ptr) != .Success) return null;
return ptr;
}
fn uefi_resize(
_: *anyopaque,
buf: []u8,
log2_old_ptr_align: u8,
new_len: usize,
ret_addr: usize,
) bool {
_ = ret_addr;
std.debug.assert(log2_old_ptr_align <= 3);
if (new_len > buf.len) return false;
_ = mem.alignAllocLen(buf.len, new_len, 8);
return true;
}
fn uefi_free(
_: *anyopaque,
buf: []u8,
log2_old_ptr_align: u8,
ret_addr: usize,
) void {
_ = log2_old_ptr_align;
_ = ret_addr;
_ = uefi.system_table.boot_services.?.freePool(@alignCast(8, buf.ptr));
}