From 4352b8aee98005853aa63f57d6377282de17a33f Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 23 Aug 2026 13:28:57 -0700 Subject: Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux Pull I3C updates from Alexandre Belloni: "A new driver this cycle, for the AMD AXI I3C controller. There are also new features such as IBI wakeup support, SETAASA device discovery and ACPI support for the the DAA methods, meaning we can now communicate with the SPD devices on DDR5 modules. New driver: - AMD AXI I3C master controller Subsystem: - I3C Common Command Code (CCC) handling improvements, especially around GET CCCs - SETAASA device discovery support - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as well as I2C devices on I3C bus - IBI-based wakeup support Drivers: - dw: SETAASA support - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C controller support, PIO queue management support for HCI v1.2 - renesas: improve suspend to RAM support, add runtime PM support" * tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits) i3c: dw: reduce do_daa time if there's no client i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2 i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode i3c: dw: rename "pclk" to "apb" to match dt-binding i3c: dw: make struct dw_i3c_cmd smaller i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding i3c: renesas: Don't register devices when ENTDAA times out i3c: master: dw-i3c-master: fix OD timing for first broadcast i3c: mipi-i3c-hci: Advertise IBI wakeup capability i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev() i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI i3c: master: Reject IBI requests from non-IBI-capable devices i3c: master: Add helper to query bus wakeup requirements i3c: master: Report wakeup events for IBIs i3c: master: Support IBI-based wakeup capability i3c: master: Fix potential UAF in i3c_device_match() i3c: master: Fix potential UAF in i3c_device_uevent() i3c: Make dev->desc locking assumptions explicit i3c: master: Fix use-after-free of master->this ... --- drivers/android/binder/context.rs | 175 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 175 insertions(+) create mode 100644 drivers/android/binder/context.rs (limited to 'drivers/android/binder/context.rs') diff --git a/drivers/android/binder/context.rs b/drivers/android/binder/context.rs new file mode 100644 index 000000000..ddddb66b3 --- /dev/null +++ b/drivers/android/binder/context.rs @@ -0,0 +1,175 @@ +// SPDX-License-Identifier: GPL-2.0 + +// Copyright (C) 2025 Google LLC. + +use kernel::{ + alloc::kvec::KVVec, + error::code::*, + prelude::*, + security, + str::{CStr, CString}, + sync::{Arc, Mutex}, + task::Kuid, +}; + +use crate::{error::BinderError, node::NodeRef, process::Process}; + +kernel::sync::global_lock! { + // SAFETY: We call `init` in the module initializer, so it's initialized before first use. + pub(crate) unsafe(uninit) static CONTEXTS: Mutex = ContextList { + contexts: KVVec::new(), + }; +} + +pub(crate) struct ContextList { + contexts: KVVec>, +} + +pub(crate) fn get_all_contexts() -> Result>> { + let lock = CONTEXTS.lock(); + let mut ctxs = KVVec::with_capacity(lock.contexts.len(), GFP_KERNEL)?; + for ctx in lock.contexts.iter() { + ctxs.push(ctx.clone(), GFP_KERNEL)?; + } + Ok(ctxs) +} + +/// This struct keeps track of the processes using this context, and which process is the context +/// manager. +struct Manager { + node: Option, + uid: Option, + all_procs: KVVec>, +} + +/// There is one context per binder file (/dev/binder, /dev/hwbinder, etc) +#[pin_data] +pub(crate) struct Context { + #[pin] + manager: Mutex, + pub(crate) name: CString, +} + +impl Context { + pub(crate) fn new(name: &CStr) -> Result> { + let name = CString::try_from(name)?; + let ctx = Arc::pin_init( + try_pin_init!(Context { + name, + manager <- kernel::new_mutex!(Manager { + all_procs: KVVec::new(), + node: None, + uid: None, + }, "Context::manager"), + }), + GFP_KERNEL, + )?; + + CONTEXTS.lock().contexts.push(ctx.clone(), GFP_KERNEL)?; + + Ok(ctx) + } + + /// Called when the file for this context is unlinked. + /// + /// No-op if called twice. + pub(crate) fn deregister(self: &Arc) { + // Safe removal using retain + CONTEXTS.lock().contexts.retain(|c| !Arc::ptr_eq(c, self)); + } + + pub(crate) fn register_process(self: &Arc, proc: Arc) -> Result { + if !Arc::ptr_eq(self, &proc.ctx) { + pr_err!("Context::register_process called on the wrong context."); + return Err(EINVAL); + } + self.manager.lock().all_procs.push(proc, GFP_KERNEL)?; + Ok(()) + } + + pub(crate) fn deregister_process(self: &Arc, proc: &Arc) { + if !Arc::ptr_eq(self, &proc.ctx) { + pr_err!("Context::deregister_process called on the wrong context."); + return; + } + let mut manager = self.manager.lock(); + manager.all_procs.retain(|p| !Arc::ptr_eq(p, proc)); + + // Shrink the vector if it has significant unused capacity to avoid memory waste, + // but use a conservative strategy to prevent shrink-then-regrow oscillation. + // Only shrink when length drops below 1/4 of capacity, and shrink to twice the length. + let len = manager.all_procs.len(); + let cap = manager.all_procs.capacity(); + if len < cap / 4 { + // Shrink to twice the current length. Ignore allocation failures since this + // is just an optimization; the vector remains valid even if shrinking fails. + let _ = manager.all_procs.shrink_to(len * 2, GFP_KERNEL); + } + } + + pub(crate) fn set_manager_node(&self, node_ref: NodeRef) -> Result { + let mut manager = self.manager.lock(); + if manager.node.is_some() { + pr_warn!("BINDER_SET_CONTEXT_MGR already set"); + return Err(EBUSY); + } + security::binder_set_context_mgr(&node_ref.node.owner.cred)?; + + // If the context manager has been set before, ensure that we use the same euid. + let caller_uid = Kuid::current_euid(); + if let Some(ref uid) = manager.uid { + if *uid != caller_uid { + return Err(EPERM); + } + } + + manager.node = Some(node_ref); + manager.uid = Some(caller_uid); + Ok(()) + } + + pub(crate) fn unset_manager_node(&self) { + let node_ref = self.manager.lock().node.take(); + drop(node_ref); + } + + pub(crate) fn get_manager_node(&self, strong: bool) -> Result { + self.manager + .lock() + .node + .as_ref() + .ok_or_else(BinderError::new_dead)? + .clone(strong) + .map_err(BinderError::from) + } + + pub(crate) fn for_each_proc(&self, mut func: F) + where + F: FnMut(&Process), + { + let lock = self.manager.lock(); + for proc in &lock.all_procs { + func(proc); + } + } + + pub(crate) fn get_all_procs(&self) -> Result>> { + let lock = self.manager.lock(); + let mut procs = KVVec::with_capacity(lock.all_procs.len(), GFP_KERNEL)?; + for proc in lock.all_procs.iter() { + procs.push(Arc::clone(proc), GFP_KERNEL)?; + } + Ok(procs) + } + + pub(crate) fn get_procs_with_pid(&self, pid: i32) -> Result>> { + let lock = self.manager.lock(); + let mut matching_procs = KVVec::new(); + for proc in lock.all_procs.iter() { + if proc.task.pid() == pid { + matching_procs.push(Arc::clone(proc), GFP_KERNEL)?; + } + } + Ok(matching_procs) + } +} -- cgit v1.3.1