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use core::convert::TryInto;
use core::sync::atomic::{AtomicUsize, Ordering};
use multiboot::information::{MemoryType, Multiboot};
use crate::arch::x86_64::kernel::{get_limit, get_mbinfo};
use crate::arch::x86_64::mm::paging::{BasePageSize, PageSize};
use crate::arch::x86_64::mm::MEM;
use crate::arch::x86_64::mm::{PhysAddr, VirtAddr};
use crate::mm;
use crate::mm::freelist::{FreeList, FreeListEntry};
use crate::synch::spinlock::*;
static PHYSICAL_FREE_LIST: SpinlockIrqSave<FreeList> = SpinlockIrqSave::new(FreeList::new());
static TOTAL_MEMORY: AtomicUsize = AtomicUsize::new(0);
fn detect_from_multiboot_info() -> Result<(), ()> {
let mb_info = get_mbinfo();
if mb_info.is_zero() {
return Err(());
}
let mb = unsafe { Multiboot::from_ptr(mb_info.as_u64(), &mut MEM).unwrap() };
let all_regions = mb
.memory_regions()
.expect("Could not find a memory map in the Multiboot information");
let ram_regions = all_regions.filter(|m| {
m.memory_type() == MemoryType::Available
&& m.base_address() + m.length() > mm::kernel_end_address().as_u64()
});
let mut found_ram = false;
for m in ram_regions {
found_ram = true;
let start_address = if m.base_address() <= mm::kernel_start_address().as_u64() {
mm::kernel_end_address()
} else {
VirtAddr(m.base_address())
};
let entry = FreeListEntry::new(
start_address.as_usize(),
(m.base_address() + m.length()) as usize,
);
let _ = TOTAL_MEMORY.fetch_add((m.base_address() + m.length()) as usize, Ordering::SeqCst);
PHYSICAL_FREE_LIST.lock().list.push_back(entry);
}
assert!(
found_ram,
"Could not find any available RAM in the Multiboot Memory Map"
);
Ok(())
}
fn detect_from_limits() -> Result<(), ()> {
let apic_gap = 0xFE000000;
let limit = get_limit();
if limit == 0 {
return Err(());
}
if limit > apic_gap {
let entry = FreeListEntry::new(mm::kernel_end_address().as_usize(), apic_gap);
PHYSICAL_FREE_LIST.lock().list.push_back(entry);
if limit > 0x100000000 {
let entry = FreeListEntry::new(0x100000000, limit - 0x100000000);
PHYSICAL_FREE_LIST.lock().list.push_back(entry);
TOTAL_MEMORY.store(limit - (0x100000000 - apic_gap), Ordering::SeqCst);
} else {
TOTAL_MEMORY.store(apic_gap, Ordering::SeqCst);
}
} else {
let entry = FreeListEntry::new(mm::kernel_end_address().as_usize(), limit);
PHYSICAL_FREE_LIST.lock().list.push_back(entry);
TOTAL_MEMORY.store(limit, Ordering::SeqCst);
}
Ok(())
}
pub fn init() {
detect_from_multiboot_info()
.or_else(|_e| detect_from_limits())
.unwrap();
}
pub fn total_memory_size() -> usize {
TOTAL_MEMORY.load(Ordering::SeqCst)
}
pub fn allocate(size: usize) -> Result<PhysAddr, ()> {
assert!(size > 0);
assert_eq!(
size % BasePageSize::SIZE,
0,
"Size {:#X} is not a multiple of {:#X}",
size,
BasePageSize::SIZE
);
Ok(PhysAddr(
PHYSICAL_FREE_LIST
.lock()
.allocate(size, None)?
.try_into()
.unwrap(),
))
}
pub fn allocate_aligned(size: usize, alignment: usize) -> Result<PhysAddr, ()> {
assert!(size > 0);
assert!(alignment > 0);
assert_eq!(
size % alignment,
0,
"Size {:#X} is not a multiple of the given alignment {:#X}",
size,
alignment
);
assert_eq!(
alignment % BasePageSize::SIZE,
0,
"Alignment {:#X} is not a multiple of {:#X}",
alignment,
BasePageSize::SIZE
);
Ok(PhysAddr(
PHYSICAL_FREE_LIST
.lock()
.allocate(size, Some(alignment))?
.try_into()
.unwrap(),
))
}
pub fn deallocate(physical_address: PhysAddr, size: usize) {
assert!(
physical_address >= PhysAddr(mm::kernel_end_address().as_u64()),
"Physical address {:#X} is not >= KERNEL_END_ADDRESS",
physical_address
);
assert!(size > 0);
assert_eq!(
size % BasePageSize::SIZE,
0,
"Size {:#X} is not a multiple of {:#X}",
size,
BasePageSize::SIZE
);
PHYSICAL_FREE_LIST
.lock()
.deallocate(physical_address.as_usize(), size);
}
pub fn print_information() {
PHYSICAL_FREE_LIST
.lock()
.print_information(" PHYSICAL MEMORY FREE LIST ");
}