Skip to content

fix(mm): don't account for kernel executable memory twice #2593

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
mkroening merged 1 commit into from
Aug 3, 2026
Merged

fix(mm): don't account for kernel executable memory twice #2593

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
8 changes: 0 additions & 8 deletions src/env.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,6 @@ use hashbrown::HashMap;
use hashbrown::hash_map::Iter;
use hermit_entry::boot_info::{BootInfo, RawBootInfo};
use hermit_sync::OnceCell;
use memory_addresses::PhysAddr;
use shlex::Shlex;

static BOOT_INFO: OnceCell<BootInfo> = OnceCell::new();
Expand Down Expand Up @@ -108,13 +107,6 @@ pub fn fdt() -> Option<Fdt<'static>> {
})
}

pub(crate) fn get_ram_address() -> Option<PhysAddr> {
let fdt = fdt()?;
let memory = fdt.memory();
let ptr = memory.regions().next()?.starting_address;
Some(ptr.expose_provenance().into())
}

/// Returns the RSDP physical address if available.
#[cfg(all(target_arch = "x86_64", feature = "acpi"))]
pub fn rsdp() -> Option<NonZero<usize>> {
Expand Down
12 changes: 2 additions & 10 deletions src/mm/mod.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -61,11 +61,11 @@ use talc::source::Manual;
pub use self::page_range_alloc::{PageRangeAllocator, PageRangeBox};
pub use self::physicalmem::{FrameAlloc, FrameBox};
pub use self::virtualmem::{PageAlloc, PageBox};
use crate::arch;
#[cfg(any(target_arch = "x86_64", target_arch = "riscv64"))]
use crate::arch::mm::paging::HugePageSize;
pub use crate::arch::mm::paging::virtual_to_physical;
use crate::arch::mm::paging::{BasePageSize, LargePageSize, PageSize};
use crate::{arch, env};

#[cfg(target_os = "none")]
#[global_allocator]
Expand Down Expand Up @@ -135,20 +135,12 @@ pub(crate) fn init() {
let npage_3tables = npages / npage_div + 1;
let npage_2tables = npage_3tables / npage_div + 1;
let npage_1tables = npage_2tables / npage_div + 1;
let reserved_space = (npage_3tables + npage_2tables + npage_1tables)
* BasePageSize::SIZE as usize
let min_mem = (npage_3tables + npage_2tables + npage_1tables) * BasePageSize::SIZE as usize
+ 2 * LargePageSize::SIZE as usize;
#[cfg(any(target_arch = "x86_64", target_arch = "riscv64"))]
let has_1gib_pages = arch::kernel::processor::supports_1gib_pages();
let has_2mib_pages = arch::kernel::processor::supports_2mib_pages();

let min_mem = if env::is_uefi() {
// On UEFI, the given memory is guaranteed free memory and the kernel is located before the given memory
reserved_space
} else {
(kernel_addr_range.end.as_u64() - env::get_ram_address().unwrap().as_u64()
+ reserved_space as u64) as usize
};
info!("Minimum memory size: {} MiB", min_mem >> 20);
let avail_mem = total_mem
.checked_sub(min_mem)
Expand Down
Loading