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Makes stage 2 heap honors layout alignment
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ultimaweapon committed Sep 7, 2024
1 parent 08fd525 commit a681fed
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Showing 3 changed files with 40 additions and 23 deletions.
2 changes: 2 additions & 0 deletions src/obkrnl/src/main.rs
Original file line number Diff line number Diff line change
Expand Up @@ -59,6 +59,8 @@ extern "C" fn _start(env: &'static BootEnv) -> ! {

fn main() -> ! {
// Activate stage 2 heap.
info!("Activating stage 2 heap.");

unsafe { KERNEL_HEAP.activate_stage2() };

loop {
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59 changes: 37 additions & 22 deletions src/obkrnl/src/malloc/stage2.rs
Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,7 @@ use core::alloc::Layout;
/// This stage allocate a memory from a virtual memory management system. This struct is a merge of
/// `malloc_type` and `malloc_type_internal` structure.
pub struct Stage2 {
zones: Vec<Arc<UmaZone>>, // kmemsize + kmemzones
zones: [Vec<Arc<UmaZone>>; size_of::<usize>() * 8 - 1], // kmemsize + kmemzones
}

impl Stage2 {
Expand All @@ -22,25 +22,37 @@ impl Stage2 {

/// See `kmeminit` on the PS4 for a reference.
pub fn new() -> Self {
let mut zones = Vec::with_capacity(Self::KMEM_ZSIZE + 1);
let mut last = 0;
// The possible of maximum alignment that Layout allowed is a bit before the most
// significant bit of isize (e.g. 0x4000000000000000 on 64 bit system). So we can use
// "size_of::<usize>() * 8 - 1" to get the size of array for all possible alignment.
let zones = core::array::from_fn(|align| {
let mut zones = Vec::with_capacity(Self::KMEM_ZSIZE + 1);
let mut last = 0;
let align = align
.try_into()
.ok()
.and_then(|align| 1usize.checked_shl(align))
.unwrap();

for i in Self::KMEM_ZSHIFT.. {
// Stop if size larger than page size.
let size = 1usize << i;
for i in Self::KMEM_ZSHIFT.. {
// Stop if size larger than page size.
let size = 1usize << i;

if size > PAGE_SIZE {
break;
}
if size > PAGE_SIZE {
break;
}

// Create zone.
let zone = Arc::new(UmaZone::new(size.to_string().into(), size));
// Create zone.
let zone = Arc::new(UmaZone::new(size.to_string().into(), size, align - 1));

while last <= size {
zones.push(zone.clone());
last += Self::KMEM_ZBASE;
while last <= size {
zones.push(zone.clone());
last += Self::KMEM_ZBASE;
}
}
}

zones
});

Self { zones }
}
Expand All @@ -57,18 +69,21 @@ impl Stage2 {
panic!("heap allocation in an interrupt handler is not supported");
}

// TODO: Handle alignment.
let mut size = layout.size();
// Determine how to allocate.
let size = layout.size();

if size <= PAGE_SIZE {
// Round size.
if (size & Self::KMEM_ZMASK) != 0 {
// Get zone to allocate from.
let align = layout.align().trailing_zeros() as usize;
let size = if (size & Self::KMEM_ZMASK) != 0 {
// TODO: Refactor this for readability.
size = (size + Self::KMEM_ZBASE) & !Self::KMEM_ZMASK;
}
(size + Self::KMEM_ZBASE) & !Self::KMEM_ZMASK
} else {
size
};

// TODO: There are more logic after this on the PS4.
self.zones[size >> Self::KMEM_ZSHIFT].alloc()
self.zones[align][size >> Self::KMEM_ZSHIFT].alloc()
} else {
todo!()
}
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2 changes: 1 addition & 1 deletion src/obkrnl/src/uma/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@ pub struct UmaZone {}

impl UmaZone {
/// See `uma_zcreate` on the PS4 for a reference.
pub fn new(_: Cow<'static, str>, _: usize) -> Self {
pub fn new(_: Cow<'static, str>, _: usize, _: usize) -> Self {
Self {}
}

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