1 use crate::{
2 arch::mm::LockedFrameAllocator,
3 libs::align::page_align_up,
4 mm::{MMArch, MemoryManagementArch, VirtAddr},
5 };
6
7 use core::{
8 alloc::{AllocError, GlobalAlloc, Layout},
9 intrinsics::unlikely,
10 ptr::NonNull,
11 };
12
13 use super::page_frame::{FrameAllocator, PageFrameCount};
14
15 /// 类kmalloc的分配器应当实现的trait
16 pub trait LocalAlloc {
local_alloc(&self, layout: Layout) -> *mut u817 unsafe fn local_alloc(&self, layout: Layout) -> *mut u8;
local_alloc_zeroed(&self, layout: Layout) -> *mut u818 unsafe fn local_alloc_zeroed(&self, layout: Layout) -> *mut u8;
local_dealloc(&self, ptr: *mut u8, layout: Layout)19 unsafe fn local_dealloc(&self, ptr: *mut u8, layout: Layout);
20 }
21
22 pub struct KernelAllocator;
23
24 impl KernelAllocator {
alloc_in_buddy(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError>25 unsafe fn alloc_in_buddy(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError> {
26 // 计算需要申请的页数，向上取整
27 let count = (page_align_up(layout.size()) / MMArch::PAGE_SIZE).next_power_of_two();
28 let page_frame_count = PageFrameCount::new(count);
29 let (phy_addr, allocated_frame_count) = LockedFrameAllocator
30 .allocate(page_frame_count)
31 .ok_or(AllocError)?;
32
33 let virt_addr = unsafe { MMArch::phys_2_virt(phy_addr).ok_or(AllocError)? };
34 if unlikely(virt_addr.is_null()) {
35 return Err(AllocError);
36 }
37
38 let slice = unsafe {
39 core::slice::from_raw_parts_mut(
40 virt_addr.data() as *mut u8,
41 allocated_frame_count.data() * MMArch::PAGE_SIZE,
42 )
43 };
44 return Ok(NonNull::from(slice));
45 }
46
free_in_buddy(&self, ptr: *mut u8, layout: Layout)47 unsafe fn free_in_buddy(&self, ptr: *mut u8, layout: Layout) {
48 // 由于buddy分配的页数量是2的幂，因此释放的时候也需要按照2的幂向上取整。
49 let count = (page_align_up(layout.size()) / MMArch::PAGE_SIZE).next_power_of_two();
50 let page_frame_count = PageFrameCount::new(count);
51 let phy_addr = MMArch::virt_2_phys(VirtAddr::new(ptr as usize)).unwrap();
52 LockedFrameAllocator.free(phy_addr, page_frame_count);
53 }
54 }
55
56 /// 为内核SLAB分配器实现LocalAlloc的trait
57 impl LocalAlloc for KernelAllocator {
local_alloc(&self, layout: Layout) -> *mut u858 unsafe fn local_alloc(&self, layout: Layout) -> *mut u8 {
59 return self
60 .alloc_in_buddy(layout)
61 .map(|x| x.as_mut_ptr() as *mut u8)
62 .unwrap_or(core::ptr::null_mut() as *mut u8);
63 }
64
local_alloc_zeroed(&self, layout: Layout) -> *mut u865 unsafe fn local_alloc_zeroed(&self, layout: Layout) -> *mut u8 {
66 return self
67 .alloc_in_buddy(layout)
68 .map(|x| {
69 let ptr: *mut u8 = x.as_mut_ptr();
70 core::ptr::write_bytes(ptr, 0, x.len());
71 ptr
72 })
73 .unwrap_or(core::ptr::null_mut() as *mut u8);
74 }
75
local_dealloc(&self, ptr: *mut u8, layout: Layout)76 unsafe fn local_dealloc(&self, ptr: *mut u8, layout: Layout) {
77 self.free_in_buddy(ptr, layout);
78 }
79 }
80
81 /// 为内核slab分配器实现GlobalAlloc特性
82 unsafe impl GlobalAlloc for KernelAllocator {
alloc(&self, layout: Layout) -> *mut u883 unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
84 return self.local_alloc(layout);
85 // self.local_alloc_zeroed(layout, 0)
86 }
87
alloc_zeroed(&self, layout: Layout) -> *mut u888 unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
89 self.local_alloc_zeroed(layout)
90 }
91
dealloc(&self, ptr: *mut u8, layout: Layout)92 unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
93 self.local_dealloc(ptr, layout);
94 }
95 }
96
97 /// 内存分配错误处理函数
98 #[alloc_error_handler]
global_alloc_err_handler(layout: Layout) -> !99 pub fn global_alloc_err_handler(layout: Layout) -> ! {
100 panic!("global_alloc_error, layout: {:?}", layout);
101 }
102