obkrnl/vm/

mod.rs

pub use self::object::*;
pub use self::page::*;

use self::phys::PhysAllocator;
use self::stats::VmStats;
use crate::config::{PAGE_SHIFT, PAGE_SIZE};
use crate::context::{config, current_thread};
use crate::dmem::Dmem;
use crate::lock::Mutex;
use crate::proc::Proc;
use alloc::sync::{Arc, Weak};
use alloc::vec::Vec;
use core::cmp::max;
use core::fmt::Debug;
use core::sync::atomic::{AtomicUsize, Ordering};
use krt::info;
use macros::bitflag;
use thiserror::Error;

#[cfg_attr(target_arch = "aarch64", path = "aarch64.rs")]
#[cfg_attr(target_arch = "x86_64", path = "x86_64.rs")]
mod arch;
mod object;
mod page;
mod phys;
mod stats;

/// Implementation of Virtual Memory system.
pub struct Vm {
    phys: PhysAllocator,
    pages: Vec<Arc<VmPage>>, // vm_page_array + vm_page_array_size
    stats: [Mutex<VmStats>; 2],
    pagers: [Weak<Proc>; 2],         // pageproc
    pages_deficit: [AtomicUsize; 2], // vm_pageout_deficit
}

impl Vm {
    /// See `vm_page_startup` on the Orbis for a reference.
    ///
    /// # Reference offsets
    /// | Version | Offset |
    /// |---------|--------|
    /// |PS4 11.00|0x029200|
    pub fn new(
        phys_avail: [usize; 61],
        ma: Option<&MemAffinity>,
        dmem: &Dmem,
    ) -> Result<Arc<Self>, VmError> {
        let phys = PhysAllocator::new(&phys_avail, ma);

        // Populate vm_page_array. We do a bit different than Orbis here to be able to make segind
        // immutable.
        let config = config();
        let blocked = config.env("vm.blacklist");
        let unk = dmem.game_end() - dmem.config().fmem_max.get();
        let mut pages = Vec::new();
        let mut free_pages = Vec::new();
        let mut page_count = [0; 2];
        let mut free_count = [0; 2];

        for i in (0..).step_by(2) {
            // Check if end entry.
            let addr = phys_avail[i];
            let end = phys_avail[i + 1];

            if end == 0 {
                break;
            }

            for addr in (addr..end).step_by(PAGE_SIZE.get()) {
                // Check if blocked address.
                if blocked.is_some() {
                    // TODO: We probably want to use None for segment index here. The problem is
                    // Orbis use zero here.
                    let pi = pages.len();

                    pages.push(Arc::new(VmPage::new(pi, 0, 0, addr, 0)));

                    todo!();
                }

                // Check if free page.
                let vm;
                let free = if addr < unk || addr >= dmem.game_end() {
                    // We inline a call to vm_phys_add_page() here.
                    vm = 0;

                    page_count[0] += 1;
                    free_count[0] += 1;

                    true
                } else {
                    // We inline a call to unknown function here.
                    vm = 1;

                    page_count[1] += 1;

                    false
                };

                // Add to list.
                let pi = pages.len();
                let seg = phys.segment_index(addr).unwrap();
                let page = Arc::new(VmPage::new(pi, vm, 0, addr, seg));

                if free {
                    free_pages.push(page.clone());
                }

                pages.push(page);
            }
        }

        info!(
            concat!(
                "VM stats initialized.\n",
                "v_page_count[0]: {}\n",
                "v_free_count[0]: {}\n",
                "v_page_count[1]: {}"
            ),
            page_count[0], free_count[0], page_count[1]
        );

        // Initializes stats. The Orbis initialize these data in vm_pageout function but it is
        // possible for data race so we do it here instead.
        let pageout_page_count = 0x10; // TODO: Figure out where this value come from.
        let free_reserved = [pageout_page_count + 100 + 10, pageout_page_count];
        let free_min = [free_reserved[0] + 325, free_reserved[1] + 64];
        let stats = [
            Mutex::new(VmStats {
                free_reserved: free_reserved[0],
                cache_min: if free_count[0] < 2049 {
                    // TODO: Figure out where 2049 value come from.
                    0
                } else if free_count[0] < 6145 {
                    // TODO: Figure out where 6145 value come from.
                    free_reserved[0] + free_min[0] * 2
                } else {
                    free_reserved[0] + free_min[0] * 4
                },
                cache_count: 0,
                free_count: free_count[0],
                interrupt_free_min: 2,
                wire_count: 0,
            }),
            Mutex::new(VmStats {
                free_reserved: free_reserved[1],
                cache_min: if free_count[1] < 2049 {
                    // TODO: Figure out where 2049 value come from.
                    0
                } else if free_count[1] < 6145 {
                    // TODO: Figure out where 6145 value come from.
                    free_reserved[1] + free_min[1] * 2
                } else {
                    free_reserved[1] + free_min[1] * 4
                },
                cache_count: 0,
                free_count: free_count[1],
                interrupt_free_min: 2,
                wire_count: 0,
            }),
        ];

        // Add free pages. The Orbis do this on the above loop but that is not possible for us since
        // we use that loop to populate vm_page_array.
        let mut vm = Self {
            phys,
            pages,
            stats,
            pagers: Default::default(),
            pages_deficit: [AtomicUsize::new(0), AtomicUsize::new(0)],
        };

        for page in free_pages {
            vm.free_page(&page, 0);
        }

        // Spawn page daemons. The Orbis do this in a separated sysinit but we do it here instead to
        // keep it in the VM subsystem.
        vm.spawn_pagers();

        Ok(Arc::new(vm))
    }

    /// See `vm_page_alloc` on the Orbis for a reference.
    ///
    /// # Reference offsets
    /// | Version | Offset |
    /// |---------|--------|
    /// |PS4 11.00|0x02B030|
    pub fn alloc_page(
        &self,
        obj: Option<VmObject>,
        pindex: usize,
        flags: VmAlloc,
    ) -> Option<Arc<VmPage>> {
        let vm = obj.as_ref().map_or(0, |v| v.vm());
        let td = current_thread();
        let mut stats = self.stats[vm].lock();
        let available = stats.free_count + stats.cache_count;

        if available <= stats.free_reserved {
            let p = td.proc();
            let mut flags = if Arc::as_ptr(p) == self.pagers[p.pager()].as_ptr() {
                VmAlloc::System.into()
            } else {
                flags & (VmAlloc::Interrupt | VmAlloc::System)
            };

            if (flags & (VmAlloc::Interrupt | VmAlloc::System)) == VmAlloc::Interrupt {
                flags = VmAlloc::Interrupt.into();
            }

            if flags == VmAlloc::Interrupt {
                todo!()
            } else if flags == VmAlloc::System {
                if available <= stats.interrupt_free_min {
                    let deficit = max(1, flags.get(VmAlloc::Count));

                    drop(stats);

                    self.pages_deficit[vm].fetch_add(deficit.into(), Ordering::Relaxed);
                    self.wake_pager(vm);

                    return None;
                }
            } else {
                todo!()
            }
        }

        // Allocate VmPage.
        let page = match &obj {
            Some(_) => todo!(),
            None => {
                if flags.has_any(VmAlloc::Cached) {
                    return None;
                }

                self.phys
                    .alloc_page(&self.pages, vm, obj.is_none().into(), 0)
            }
        };

        // The Orbis assume page is never null here.
        let page = page.unwrap();
        let mut ps = page.state.lock();

        match ps.flags.has_any(PageFlags::Cached) {
            true => todo!(),
            false => stats.free_count -= 1,
        }

        match ps.flags.has_any(PageFlags::Zero) {
            true => todo!(),
            false => ps.flags = PageFlags::zeroed(),
        }

        ps.access = PageAccess::zeroed();

        // Set oflags.
        let mut oflags = PageExtFlags::zeroed();

        match &obj {
            Some(_) => todo!(),
            None => oflags |= PageExtFlags::Unmanaged,
        }

        if !flags.has_any(VmAlloc::NoBusy | VmAlloc::NoObj) {
            oflags |= PageExtFlags::Busy;
        }

        ps.extended_flags = oflags;

        if flags.has_any(VmAlloc::Wired) {
            stats.wire_count += 1;
            ps.wire_count = 1;
        }

        ps.act_count = 0;

        match &obj {
            Some(_) => todo!(),
            None => ps.pindex = pindex,
        }

        // TODO: Call vdrop.
        if (stats.cache_count + stats.free_count) < (stats.cache_min + stats.free_reserved) {
            todo!()
        }

        // TODO: Set unknown field.
        drop(ps);

        Some(page)
    }

    /// `page` must not have active lock on any fields.
    ///
    /// See `vm_phys_free_pages` on the Orbis for a reference.
    ///
    /// # Reference offsets
    /// | Version | Offset |
    /// |---------|--------|
    /// |PS4 11.00|0x15FCB0|
    fn free_page(&self, page: &Arc<VmPage>, mut order: usize) {
        // Get segment the page belong to.
        let mut page = page; // For scoped lifetime.
        let vm = page.vm;
        let mut pa = page.addr;
        let seg = if (page.unk1 & 1) == 0 {
            self.phys.segment(page.segment)
        } else {
            todo!()
        };

        // TODO: What is this?
        let mut queues = seg.free_queues.lock();
        let mut ps = page.state.lock();

        while order < 12 {
            let start = seg.start;
            let buddy_pa = pa ^ (1usize << (order + PAGE_SHIFT)); // TODO: What is this?

            if buddy_pa < start || buddy_pa >= seg.end {
                break;
            }

            // Get buddy page index.
            let buddy = &self.pages[seg.first_page + ((buddy_pa - start) >> PAGE_SHIFT)];
            let mut bs = buddy.state.lock();

            if bs.order != order || buddy.vm != vm || ((page.unk1 ^ buddy.unk1) & 1) != 0 {
                break;
            }

            // TODO: Check if we really need to preserve page order here. If not we need to replace
            // IndexMap with HashMap otherwise we need to find a better solution than IndexMap.
            queues[vm][bs.pool][bs.order].shift_remove(buddy);
            bs.order = VmPage::FREE_ORDER;

            if bs.pool != ps.pool {
                todo!()
            }

            drop(bs);

            order += 1;
            pa &= !((1usize << (order + PAGE_SHIFT)) - 1);
            page = &self.pages[seg.first_page + ((pa - start) >> PAGE_SHIFT)];
            ps = page.state.lock();
        }

        // Add to free queue.
        ps.order = order;
        queues[vm][ps.pool][order].insert(page.clone());
    }

    /// See `kick_pagedaemons` on the Orbis for a reference.
    ///
    /// # Reference offsets
    /// | Version | Offset |
    /// |---------|--------|
    /// |PS4 11.00|0x3E0E40|
    fn spawn_pagers(&mut self) {
        // TODO: This requires v_page_count that populated by vm_page_startup. In order to populate
        // this we need phys_avail that populated by getmemsize.
    }

    /// See `pagedaemon_wakeup` on the Orbis for a reference.
    ///
    /// # Reference offsets
    /// | Version | Offset |
    /// |---------|--------|
    /// |PS4 11.00|0x3E0690|
    fn wake_pager(&self, _: usize) {
        todo!()
    }
}

/// Implementation of `mem_affinity` structure.
pub struct MemAffinity {}

/// Flags for [Vm::alloc_page()].
#[bitflag(u32)]
pub enum VmAlloc {
    /// `VM_ALLOC_INTERRUPT`.
    Interrupt = 0x00000001,
    /// `VM_ALLOC_SYSTEM`.
    System = 0x00000002,
    /// `VM_ALLOC_WIRED`.
    Wired = 0x00000020,
    /// `VM_ALLOC_NOOBJ`.
    NoObj = 0x00000100,
    /// `VM_ALLOC_NOBUSY`.
    NoBusy = 0x00000200,
    /// `VM_ALLOC_IFCACHED`.
    Cached = 0x00000400,
    /// `VM_ALLOC_COUNT`.
    Count(u16) = 0xFFFF0000,
}

/// Represents an error when [`Vm::new()`] fails.
#[derive(Debug, Error)]
pub enum VmError {}