Merge tag 'char-misc-6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-miscHEADtorvalds/mastertorvalds/HEADmaster

Pull Char/Misc/IIO/Binder updates from Greg KH:
 "Here is the big set of char/misc/iio and other driver subsystem
  changes for 6.18-rc1.

  Loads of different stuff in here, it was a busy development cycle in
  lots of different subsystems, with over 27k new lines added to the
  tree.

  Included in here are:

   - IIO updates including new drivers, reworking of existing apis, and
     other goodness in the sensor subsystems

   - MEI driver updates and additions

   - NVMEM driver updates

   - slimbus removal for an unused driver and some other minor updates

   - coresight driver updates and additions

   - MHI driver updates

   - comedi driver updates and fixes

   - extcon driver updates

   - interconnect driver additions

   - eeprom driver updates and fixes

   - minor UIO driver updates

   - tiny W1 driver updates

  But the majority of new code is in the rust bindings and additions,
  which includes:

   - misc driver rust binding updates for read/write support, we can now
     write "normal" misc drivers in rust fully, and the sample driver
     shows how this can be done.

   - Initial framework for USB driver rust bindings, which are disabled
     for now in the build, due to limited support, but coming in through
     this tree due to dependencies on other rust binding changes that
     were in here. I'll be enabling these back on in the build in the
     usb.git tree after -rc1 is out so that developers can continue to
     work on these in linux-next over the next development cycle.

   - Android Binder driver implemented in Rust.

     This is the big one, and was driving a huge majority of the rust
     binding work over the past years. Right now there are two binder
     drivers in the kernel, selected only at build time as to which one
     to use as binder wants to be included in the system at boot time.

     The binder C maintainers all agreed on this, as eventually, they
     want the C code to be removed from the tree, but it will take a few
     releases to get there while both are maintained to ensure that the
     rust implementation is fully stable and compliant with the existing
     userspace apis.

  All of these have been in linux-next for a while"

* tag 'char-misc-6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (320 commits)
  rust: usb: keep usb::Device private for now
  rust: usb: don't retain device context for the interface parent
  USB: disable rust bindings from the build for now
  samples: rust: add a USB driver sample
  rust: usb: add basic USB abstractions
  coresight: Add label sysfs node support
  dt-bindings: arm: Add label in the coresight components
  coresight: tnoc: add new AMBA ID to support Trace Noc V2
  coresight: Fix incorrect handling for return value of devm_kzalloc
  coresight: tpda: fix the logic to setup the element size
  coresight: trbe: Return NULL pointer for allocation failures
  coresight: Refactor runtime PM
  coresight: Make clock sequence consistent
  coresight: Refactor driver data allocation
  coresight: Consolidate clock enabling
  coresight: Avoid enable programming clock duplicately
  coresight: Appropriately disable trace bus clocks
  coresight: Appropriately disable programming clocks
  coresight: etm4x: Support atclk
  coresight: catu: Support atclk
  ...

1 files changed, 488 insertions, 0 deletions

diff --git a/drivers/android/binder/range_alloc/tree.rs b/drivers/android/binder/range_alloc/tree.rs
new file mode 100644
index 000000000000..7b1a248fcb02
--- /dev/null
+++ b/drivers/android/binder/range_alloc/tree.rs
@@ -0,0 +1,488 @@
+// SPDX-License-Identifier: GPL-2.0
+
+// Copyright (C) 2025 Google LLC.
+
+use kernel::{
+    page::PAGE_SIZE,
+    prelude::*,
+    rbtree::{RBTree, RBTreeNode, RBTreeNodeReservation},
+    seq_file::SeqFile,
+    seq_print,
+    task::Pid,
+};
+
+use crate::range_alloc::{DescriptorState, FreedRange, Range};
+
+/// Keeps track of allocations in a process' mmap.
+///
+/// Each process has an mmap where the data for incoming transactions will be placed. This struct
+/// keeps track of allocations made in the mmap. For each allocation, we store a descriptor that
+/// has metadata related to the allocation. We also keep track of available free space.
+pub(super) struct TreeRangeAllocator<T> {
+    /// This collection contains descriptors for *both* ranges containing an allocation, *and* free
+    /// ranges between allocations. The free ranges get merged, so there are never two free ranges
+    /// next to each other.
+    tree: RBTree<usize, Descriptor<T>>,
+    /// Contains an entry for every free range in `self.tree`. This tree sorts the ranges by size,
+    /// letting us look up the smallest range whose size is at least some lower bound.
+    free_tree: RBTree<FreeKey, ()>,
+    size: usize,
+    free_oneway_space: usize,
+}
+
+impl<T> TreeRangeAllocator<T> {
+    pub(crate) fn from_array(
+        size: usize,
+        ranges: &mut KVec<Range<T>>,
+        alloc: &mut FromArrayAllocs<T>,
+    ) -> Self {
+        let mut tree = TreeRangeAllocator {
+            tree: RBTree::new(),
+            free_tree: RBTree::new(),
+            size,
+            free_oneway_space: size / 2,
+        };
+
+        let mut free_offset = 0;
+        for range in ranges.drain_all() {
+            let free_size = range.offset - free_offset;
+            if free_size > 0 {
+                let free_node = alloc.free_tree.pop().unwrap();
+                tree.free_tree
+                    .insert(free_node.into_node((free_size, free_offset), ()));
+                let tree_node = alloc.tree.pop().unwrap();
+                tree.tree.insert(
+                    tree_node.into_node(free_offset, Descriptor::new(free_offset, free_size)),
+                );
+            }
+            free_offset = range.endpoint();
+
+            if range.state.is_oneway() {
+                tree.free_oneway_space = tree.free_oneway_space.saturating_sub(range.size);
+            }
+
+            let free_res = alloc.free_tree.pop().unwrap();
+            let tree_node = alloc.tree.pop().unwrap();
+            let mut desc = Descriptor::new(range.offset, range.size);
+            desc.state = Some((range.state, free_res));
+            tree.tree.insert(tree_node.into_node(range.offset, desc));
+        }
+
+        // After the last range, we may need a free range.
+        if free_offset < size {
+            let free_size = size - free_offset;
+            let free_node = alloc.free_tree.pop().unwrap();
+            tree.free_tree
+                .insert(free_node.into_node((free_size, free_offset), ()));
+            let tree_node = alloc.tree.pop().unwrap();
+            tree.tree
+                .insert(tree_node.into_node(free_offset, Descriptor::new(free_offset, free_size)));
+        }
+
+        tree
+    }
+
+    pub(crate) fn is_empty(&self) -> bool {
+        let mut tree_iter = self.tree.values();
+        // There's always at least one range, because index zero is either the start of a free or
+        // allocated range.
+        let first_value = tree_iter.next().unwrap();
+        if tree_iter.next().is_some() {
+            // There are never two free ranges next to each other, so if there is more than one
+            // descriptor, then at least one of them must hold an allocated range.
+            return false;
+        }
+        // There is only one descriptor. Return true if it is for a free range.
+        first_value.state.is_none()
+    }
+
+    pub(crate) fn total_size(&self) -> usize {
+        self.size
+    }
+
+    pub(crate) fn free_oneway_space(&self) -> usize {
+        self.free_oneway_space
+    }
+
+    pub(crate) fn count_buffers(&self) -> usize {
+        self.tree
+            .values()
+            .filter(|desc| desc.state.is_some())
+            .count()
+    }
+
+    pub(crate) fn debug_print(&self, m: &SeqFile) -> Result<()> {
+        for desc in self.tree.values() {
+            let state = match &desc.state {
+                Some(state) => &state.0,
+                None => continue,
+            };
+            seq_print!(
+                m,
+                "  buffer: {} size {} pid {}",
+                desc.offset,
+                desc.size,
+                state.pid(),
+            );
+            if state.is_oneway() {
+                seq_print!(m, " oneway");
+            }
+            match state {
+                DescriptorState::Reserved(_res) => {
+                    seq_print!(m, " reserved\n");
+                }
+                DescriptorState::Allocated(_alloc) => {
+                    seq_print!(m, " allocated\n");
+                }
+            }
+        }
+        Ok(())
+    }
+
+    fn find_best_match(&mut self, size: usize) -> Option<&mut Descriptor<T>> {
+        let free_cursor = self.free_tree.cursor_lower_bound(&(size, 0))?;
+        let ((_, offset), ()) = free_cursor.current();
+        self.tree.get_mut(offset)
+    }
+
+    /// Try to reserve a new buffer, using the provided allocation if necessary.
+    pub(crate) fn reserve_new(
+        &mut self,
+        debug_id: usize,
+        size: usize,
+        is_oneway: bool,
+        pid: Pid,
+        alloc: ReserveNewTreeAlloc<T>,
+    ) -> Result<(usize, bool)> {
+        // Compute new value of free_oneway_space, which is set only on success.
+        let new_oneway_space = if is_oneway {
+            match self.free_oneway_space.checked_sub(size) {
+                Some(new_oneway_space) => new_oneway_space,
+                None => return Err(ENOSPC),
+            }
+        } else {
+            self.free_oneway_space
+        };
+
+        // Start detecting spammers once we have less than 20%
+        // of async space left (which is less than 10% of total
+        // buffer size).
+        //
+        // (This will short-circut, so `low_oneway_space` is
+        // only called when necessary.)
+        let oneway_spam_detected =
+            is_oneway && new_oneway_space < self.size / 10 && self.low_oneway_space(pid);
+
+        let (found_size, found_off, tree_node, free_tree_node) = match self.find_best_match(size) {
+            None => {
+                pr_warn!("ENOSPC from range_alloc.reserve_new - size: {}", size);
+                return Err(ENOSPC);
+            }
+            Some(desc) => {
+                let found_size = desc.size;
+                let found_offset = desc.offset;
+
+                // In case we need to break up the descriptor
+                let new_desc = Descriptor::new(found_offset + size, found_size - size);
+                let (tree_node, free_tree_node, desc_node_res) = alloc.initialize(new_desc);
+
+                desc.state = Some((
+                    DescriptorState::new(is_oneway, debug_id, pid),
+                    desc_node_res,
+                ));
+                desc.size = size;
+
+                (found_size, found_offset, tree_node, free_tree_node)
+            }
+        };
+        self.free_oneway_space = new_oneway_space;
+        self.free_tree.remove(&(found_size, found_off));
+
+        if found_size != size {
+            self.tree.insert(tree_node);
+            self.free_tree.insert(free_tree_node);
+        }
+
+        Ok((found_off, oneway_spam_detected))
+    }
+
+    pub(crate) fn reservation_abort(&mut self, offset: usize) -> Result<FreedRange> {
+        let mut cursor = self.tree.cursor_lower_bound(&offset).ok_or_else(|| {
+            pr_warn!(
+                "EINVAL from range_alloc.reservation_abort - offset: {}",
+                offset
+            );
+            EINVAL
+        })?;
+
+        let (_, desc) = cursor.current_mut();
+
+        if desc.offset != offset {
+            pr_warn!(
+                "EINVAL from range_alloc.reservation_abort - offset: {}",
+                offset
+            );
+            return Err(EINVAL);
+        }
+
+        let (reservation, free_node_res) = desc.try_change_state(|state| match state {
+            Some((DescriptorState::Reserved(reservation), free_node_res)) => {
+                (None, Ok((reservation, free_node_res)))
+            }
+            None => {
+                pr_warn!(
+                    "EINVAL from range_alloc.reservation_abort - offset: {}",
+                    offset
+                );
+                (None, Err(EINVAL))
+            }
+            allocated => {
+                pr_warn!(
+                    "EPERM from range_alloc.reservation_abort - offset: {}",
+                    offset
+                );
+                (allocated, Err(EPERM))
+            }
+        })?;
+
+        let mut size = desc.size;
+        let mut offset = desc.offset;
+        let free_oneway_space_add = if reservation.is_oneway { size } else { 0 };
+
+        self.free_oneway_space += free_oneway_space_add;
+
+        let mut freed_range = FreedRange::interior_pages(offset, size);
+        // Compute how large the next free region needs to be to include one more page in
+        // the newly freed range.
+        let add_next_page_needed = match (offset + size) % PAGE_SIZE {
+            0 => usize::MAX,
+            unalign => PAGE_SIZE - unalign,
+        };
+        // Compute how large the previous free region needs to be to include one more page
+        // in the newly freed range.
+        let add_prev_page_needed = match offset % PAGE_SIZE {
+            0 => usize::MAX,
+            unalign => unalign,
+        };
+
+        // Merge next into current if next is free
+        let remove_next = match cursor.peek_next() {
+            Some((_, next)) if next.state.is_none() => {
+                if next.size >= add_next_page_needed {
+                    freed_range.end_page_idx += 1;
+                }
+                self.free_tree.remove(&(next.size, next.offset));
+                size += next.size;
+                true
+            }
+            _ => false,
+        };
+
+        if remove_next {
+            let (_, desc) = cursor.current_mut();
+            desc.size = size;
+            cursor.remove_next();
+        }
+
+        // Merge current into prev if prev is free
+        match cursor.peek_prev_mut() {
+            Some((_, prev)) if prev.state.is_none() => {
+                if prev.size >= add_prev_page_needed {
+                    freed_range.start_page_idx -= 1;
+                }
+                // merge previous with current, remove current
+                self.free_tree.remove(&(prev.size, prev.offset));
+                offset = prev.offset;
+                size += prev.size;
+                prev.size = size;
+                cursor.remove_current();
+            }
+            _ => {}
+        };
+
+        self.free_tree
+            .insert(free_node_res.into_node((size, offset), ()));
+
+        Ok(freed_range)
+    }
+
+    pub(crate) fn reservation_commit(&mut self, offset: usize, data: &mut Option<T>) -> Result {
+        let desc = self.tree.get_mut(&offset).ok_or(ENOENT)?;
+
+        desc.try_change_state(|state| match state {
+            Some((DescriptorState::Reserved(reservation), free_node_res)) => (
+                Some((
+                    DescriptorState::Allocated(reservation.allocate(data.take())),
+                    free_node_res,
+                )),
+                Ok(()),
+            ),
+            other => (other, Err(ENOENT)),
+        })
+    }
+
+    /// Takes an entry at the given offset from [`DescriptorState::Allocated`] to
+    /// [`DescriptorState::Reserved`].
+    ///
+    /// Returns the size of the existing entry and the data associated with it.
+    pub(crate) fn reserve_existing(&mut self, offset: usize) -> Result<(usize, usize, Option<T>)> {
+        let desc = self.tree.get_mut(&offset).ok_or_else(|| {
+            pr_warn!(
+                "ENOENT from range_alloc.reserve_existing - offset: {}",
+                offset
+            );
+            ENOENT
+        })?;
+
+        let (debug_id, data) = desc.try_change_state(|state| match state {
+            Some((DescriptorState::Allocated(allocation), free_node_res)) => {
+                let (reservation, data) = allocation.deallocate();
+                let debug_id = reservation.debug_id;
+                (
+                    Some((DescriptorState::Reserved(reservation), free_node_res)),
+                    Ok((debug_id, data)),
+                )
+            }
+            other => {
+                pr_warn!(
+                    "ENOENT from range_alloc.reserve_existing - offset: {}",
+                    offset
+                );
+                (other, Err(ENOENT))
+            }
+        })?;
+
+        Ok((desc.size, debug_id, data))
+    }
+
+    /// Call the provided callback at every allocated region.
+    ///
+    /// This destroys the range allocator. Used only during shutdown.
+    pub(crate) fn take_for_each<F: Fn(usize, usize, usize, Option<T>)>(&mut self, callback: F) {
+        for (_, desc) in self.tree.iter_mut() {
+            if let Some((DescriptorState::Allocated(allocation), _)) = &mut desc.state {
+                callback(
+                    desc.offset,
+                    desc.size,
+                    allocation.debug_id(),
+                    allocation.take(),
+                );
+            }
+        }
+    }
+
+    /// Find the amount and size of buffers allocated by the current caller.
+    ///
+    /// The idea is that once we cross the threshold, whoever is responsible
+    /// for the low async space is likely to try to send another async transaction,
+    /// and at some point we'll catch them in the act.  This is more efficient
+    /// than keeping a map per pid.
+    fn low_oneway_space(&self, calling_pid: Pid) -> bool {
+        let mut total_alloc_size = 0;
+        let mut num_buffers = 0;
+        for (_, desc) in self.tree.iter() {
+            if let Some((state, _)) = &desc.state {
+                if state.is_oneway() && state.pid() == calling_pid {
+                    total_alloc_size += desc.size;
+                    num_buffers += 1;
+                }
+            }
+        }
+
+        // Warn if this pid has more than 50 transactions, or more than 50% of
+        // async space (which is 25% of total buffer size). Oneway spam is only
+        // detected when the threshold is exceeded.
+        num_buffers > 50 || total_alloc_size > self.size / 4
+    }
+}
+
+type TreeDescriptorState<T> = (DescriptorState<T>, FreeNodeRes);
+struct Descriptor<T> {
+    size: usize,
+    offset: usize,
+    state: Option<TreeDescriptorState<T>>,
+}
+
+impl<T> Descriptor<T> {
+    fn new(offset: usize, size: usize) -> Self {
+        Self {
+            size,
+            offset,
+            state: None,
+        }
+    }
+
+    fn try_change_state<F, Data>(&mut self, f: F) -> Result<Data>
+    where
+        F: FnOnce(Option<TreeDescriptorState<T>>) -> (Option<TreeDescriptorState<T>>, Result<Data>),
+    {
+        let (new_state, result) = f(self.state.take());
+        self.state = new_state;
+        result
+    }
+}
+
+// (Descriptor.size, Descriptor.offset)
+type FreeKey = (usize, usize);
+type FreeNodeRes = RBTreeNodeReservation<FreeKey, ()>;
+
+/// An allocation for use by `reserve_new`.
+pub(crate) struct ReserveNewTreeAlloc<T> {
+    tree_node_res: RBTreeNodeReservation<usize, Descriptor<T>>,
+    free_tree_node_res: FreeNodeRes,
+    desc_node_res: FreeNodeRes,
+}
+
+impl<T> ReserveNewTreeAlloc<T> {
+    pub(crate) fn try_new() -> Result<Self> {
+        let tree_node_res = RBTreeNodeReservation::new(GFP_KERNEL)?;
+        let free_tree_node_res = RBTreeNodeReservation::new(GFP_KERNEL)?;
+        let desc_node_res = RBTreeNodeReservation::new(GFP_KERNEL)?;
+        Ok(Self {
+            tree_node_res,
+            free_tree_node_res,
+            desc_node_res,
+        })
+    }
+
+    fn initialize(
+        self,
+        desc: Descriptor<T>,
+    ) -> (
+        RBTreeNode<usize, Descriptor<T>>,
+        RBTreeNode<FreeKey, ()>,
+        FreeNodeRes,
+    ) {
+        let size = desc.size;
+        let offset = desc.offset;
+        (
+            self.tree_node_res.into_node(offset, desc),
+            self.free_tree_node_res.into_node((size, offset), ()),
+            self.desc_node_res,
+        )
+    }
+}
+
+/// An allocation for creating a tree from an `ArrayRangeAllocator`.
+pub(crate) struct FromArrayAllocs<T> {
+    tree: KVec<RBTreeNodeReservation<usize, Descriptor<T>>>,
+    free_tree: KVec<RBTreeNodeReservation<FreeKey, ()>>,
+}
+
+impl<T> FromArrayAllocs<T> {
+    pub(crate) fn try_new(len: usize) -> Result<Self> {
+        let num_descriptors = 2 * len + 1;
+
+        let mut tree = KVec::with_capacity(num_descriptors, GFP_KERNEL)?;
+        for _ in 0..num_descriptors {
+            tree.push(RBTreeNodeReservation::new(GFP_KERNEL)?, GFP_KERNEL)?;
+        }
+
+        let mut free_tree = KVec::with_capacity(num_descriptors, GFP_KERNEL)?;
+        for _ in 0..num_descriptors {
+            free_tree.push(RBTreeNodeReservation::new(GFP_KERNEL)?, GFP_KERNEL)?;
+        }
+
+        Ok(Self { tree, free_tree })
+    }
+}