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Ignore invalid APIC entries

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This commit is contained in:
Ruihan Li 2025-04-01 16:08:17 +08:00 committed by Junyang Zhang
parent 0bbd56ecf3
commit 8f72192f07
3 changed files with 40 additions and 37 deletions
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2
ostd/src/arch/riscv/boot/smp.rs
View File

@ -2,7 +2,7 @@
//! Multiprocessor Boot Support
pub(crate) fn get_num_processors() -> Option<u32> {
pub(crate) fn count_processors() -> Option<u32> {
Some(1)
}

71
ostd/src/arch/x86/boot/smp.rs
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@ -42,53 +42,56 @@ use crate::{
mm::{paddr_to_vaddr, PAGE_SIZE},
};
/// Get the number of processors
/// Counts the number of processors.
///
/// This function needs to be called after the OS initializes the ACPI table.
pub(crate) fn get_num_processors() -> Option<u32> {
pub(crate) fn count_processors() -> Option<u32> {
let acpi_tables = get_acpi_tables()?;
let madt_table = acpi_tables.find_table::<acpi::madt::Madt>().ok()?;
// In the UEFI spec [1], for compatibility, the firmware will provide
// "Processor X2APIC structure" for local APIC ID values >= 255 and
// "Processor APIC structure" for local APIC ID values < 255, even if it is
// in the x2APIC mode.
// According to ACPI spec [1], "If this bit [the Enabled bit] is set the processor is ready for
// use. If this bit is clear and the Online Capable bit is set, system hardware supports
// enabling this processor during OS runtime."
// [1]: https://uefi.org/htmlspecs/ACPI_Spec_6_4_html/05_ACPI_Software_Programming_Model/ACPI_Software_Programming_Model.html#local-apic-flags
fn is_usable(flags: u32) -> bool {
const ENABLED: u32 = 0b01;
const ONLINE_CAPABLE: u32 = 0b10;
(flags & ENABLED) != 0 || (flags & ONLINE_CAPABLE) != 0
}
// According to ACPI spec [1], "Logical processors with APIC ID values less than 255 (whether
// in XAPIC or X2APIC mode) must use the Processor Local APIC structure to convey their APIC
// information to OSPM [..] Logical processors with APIC ID values 255 and greater must use the
// Processor Local x2APIC structure [..]"
// [1]: https://uefi.org/htmlspecs/ACPI_Spec_6_4_html/05_ACPI_Software_Programming_Model/ACPI_Software_Programming_Model.html#processor-local-x2apic-structure
let is_dup_apic = |id: u32| -> bool {
// Check if the APIC entry also shows up as an x2APIC entry.
if madt_table.get().entries().any(|e| {
matches!(e, MadtEntry::LocalX2Apic(e)
if e.x2apic_id == id && is_usable(e.flags))
}) {
log::warn!(
"Firmware bug: In MADT, APIC ID {} is also listed as an x2APIC ID",
id,
);
true
} else {
false
}
};
let local_apic_counts = madt_table
.get()
.entries()
.filter(|e| match e {
MadtEntry::LocalX2Apic(entry) => {
let processor_uid = entry.processor_uid;
let x2apic_id = entry.x2apic_id;
log::trace!(
"Found a local x2APIC entry in MADT: processor UID = {}, x2APIC ID = {}",
processor_uid,
x2apic_id,
);
true
log::trace!("Found a local x2APIC entry in MADT: {:?}", entry);
is_usable(entry.flags)
}
MadtEntry::LocalApic(entry) => {
let processor_id = entry.processor_id;
let apic_id = entry.apic_id as u32;
log::trace!(
"Found a local APIC entry in MADT: processor ID = {}, APIC ID = {}",
processor_id,
apic_id,
);
// Check if APIC entries also show up as x2APIC entries.
if madt_table
.get()
.entries()
.any(|e| matches!(e, MadtEntry::LocalX2Apic(e) if e.x2apic_id == apic_id))
{
log::warn!(
"Firmware bug: in MADT, APIC ID {} is also listed as a x2APIC ID",
apic_id
);
return false;
}
true
log::trace!("Found a local APIC entry in MADT: {:?}", entry);
is_usable(entry.flags) && !is_dup_apic(entry.apic_id as u32)
}
_ => false,
})

4
ostd/src/cpu/mod.rs
View File

@ -16,7 +16,7 @@ cfg_if::cfg_if! {
pub use set::{AtomicCpuSet, CpuSet};
use spin::Once;
use crate::{arch::boot::smp::get_num_processors, cpu_local_cell, task::atomic_mode::InAtomicMode};
use crate::{arch::boot::smp::count_processors, cpu_local_cell, task::atomic_mode::InAtomicMode};
/// The ID of a CPU in the system.
///
@ -59,7 +59,7 @@ static NUM_CPUS: Once<u32> = Once::new();
/// The caller must ensure that this function is called only once on the BSP
/// at the correct time when the number of CPUs is available from the platform.
pub(crate) unsafe fn init_num_cpus() {
let num_processors = get_num_processors().unwrap_or(1);
let num_processors = count_processors().unwrap_or(1);
NUM_CPUS.call_once(|| num_processors);
}