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authorLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
committerLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
commit5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch)
treecc5c2d0a898769fd59549594fedb3ee6f84e59a0 /kernel/jump_label.c
downloadlinux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz
linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.zip
Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted
Pull networking updates from Jakub Kicinski: "Core: - Add dedicated kmem_cache for typical/small skb->head, avoid having to access struct page at kfree time, and improve memory use. - Introduce sysctl to set default RPS configuration for new netdevs. - Define Netlink protocol specification format which can be used to describe messages used by each family and auto-generate parsers. Add tools for generating kernel data structures and uAPI headers. - Expose all net/core sysctls inside netns. - Remove 4s sleep in netpoll if carrier is instantly detected on boot. - Add configurable limit of MDB entries per port, and port-vlan. - Continue populating drop reasons throughout the stack. - Retire a handful of legacy Qdiscs and classifiers. Protocols: - Support IPv4 big TCP (TSO frames larger than 64kB). - Add IP_LOCAL_PORT_RANGE socket option, to control local port range on socket by socket basis. - Track and report in procfs number of MPTCP sockets used. - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path manager. - IPv6: don't check net.ipv6.route.max_size and rely on garbage collection to free memory (similarly to IPv4). - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986). - ICMP: add per-rate limit counters. - Add support for user scanning requests in ieee802154. - Remove static WEP support. - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate reporting. - WiFi 7 EHT channel puncturing support (client & AP). BPF: - Add a rbtree data structure following the "next-gen data structure" precedent set by recently added linked list, that is, by using kfunc + kptr instead of adding a new BPF map type. - Expose XDP hints via kfuncs with initial support for RX hash and timestamp metadata. - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to better support decap on GRE tunnel devices not operating in collect metadata. - Improve x86 JIT's codegen for PROBE_MEM runtime error checks. - Remove the need for trace_printk_lock for bpf_trace_printk and bpf_trace_vprintk helpers. - Extend libbpf's bpf_tracing.h support for tracing arguments of kprobes/uprobes and syscall as a special case. - Significantly reduce the search time for module symbols by livepatch and BPF. - Enable cpumasks to be used as kptrs, which is useful for tracing programs tracking which tasks end up running on which CPUs in different time intervals. - Add support for BPF trampoline on s390x and riscv64. - Add capability to export the XDP features supported by the NIC. - Add __bpf_kfunc tag for marking kernel functions as kfuncs. - Add cgroup.memory=nobpf kernel parameter option to disable BPF memory accounting for container environments. Netfilter: - Remove the CLUSTERIP target. It has been marked as obsolete for years, and we still have WARN splats wrt races of the out-of-band /proc interface installed by this target. - Add 'destroy' commands to nf_tables. They are identical to the existing 'delete' commands, but do not return an error if the referenced object (set, chain, rule...) did not exist. Driver API: - Improve cpumask_local_spread() locality to help NICs set the right IRQ affinity on AMD platforms. - Separate C22 and C45 MDIO bus transactions more clearly. - Introduce new DCB table to control DSCP rewrite on egress. - Support configuration of Physical Layer Collision Avoidance (PLCA) Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of shared medium Ethernet. - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing preemption of low priority frames by high priority frames. - Add support for controlling MACSec offload using netlink SET. - Rework devlink instance refcounts to allow registration and de-registration under the instance lock. Split the code into multiple files, drop some of the unnecessarily granular locks and factor out common parts of netlink operation handling. - Add TX frame aggregation parameters (for USB drivers). - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning messages with notifications for debug. - Allow offloading of UDP NEW connections via act_ct. - Add support for per action HW stats in TC. - Support hardware miss to TC action (continue processing in SW from a specific point in the action chain). - Warn if old Wireless Extension user space interface is used with modern cfg80211/mac80211 drivers. Do not support Wireless Extensions for Wi-Fi 7 devices at all. Everyone should switch to using nl80211 interface instead. - Improve the CAN bit timing configuration. Use extack to return error messages directly to user space, update the SJW handling, including the definition of a new default value that will benefit CAN-FD controllers, by increasing their oscillator tolerance. New hardware / drivers: - Ethernet: - nVidia BlueField-3 support (control traffic driver) - Ethernet support for imx93 SoCs - Motorcomm yt8531 gigabit Ethernet PHY - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA) - Microchip LAN8841 PHY (incl. cable diagnostics and PTP) - Amlogic gxl MDIO mux - WiFi: - RealTek RTL8188EU (rtl8xxxu) - Qualcomm Wi-Fi 7 devices (ath12k) - CAN: - Renesas R-Car V4H Drivers: - Bluetooth: - Set Per Platform Antenna Gain (PPAG) for Intel controllers. - Ethernet NICs: - Intel (1G, igc): - support TSN / Qbv / packet scheduling features of i226 model - Intel (100G, ice): - use GNSS subsystem instead of TTY - multi-buffer XDP support - extend support for GPIO pins to E823 devices - nVidia/Mellanox: - update the shared buffer configuration on PFC commands - implement PTP adjphase function for HW offset control - TC support for Geneve and GRE with VF tunnel offload - more efficient crypto key management method - multi-port eswitch support - Netronome/Corigine: - add DCB IEEE support - support IPsec offloading for NFP3800 - Freescale/NXP (enetc): - support XDP_REDIRECT for XDP non-linear buffers - improve reconfig, avoid link flap and waiting for idle - support MAC Merge layer - Other NICs: - sfc/ef100: add basic devlink support for ef100 - ionic: rx_push mode operation (writing descriptors via MMIO) - bnxt: use the auxiliary bus abstraction for RDMA - r8169: disable ASPM and reset bus in case of tx timeout - cpsw: support QSGMII mode for J721e CPSW9G - cpts: support pulse-per-second output - ngbe: add an mdio bus driver - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing - r8152: handle devices with FW with NCM support - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation - virtio-net: support multi buffer XDP - virtio/vsock: replace virtio_vsock_pkt with sk_buff - tsnep: XDP support - Ethernet high-speed switches: - nVidia/Mellanox (mlxsw): - add support for latency TLV (in FW control messages) - Microchip (sparx5): - separate explicit and implicit traffic forwarding rules, make the implicit rules always active - add support for egress DSCP rewrite - IS0 VCAP support (Ingress Classification) - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS etc.) - ES2 VCAP support (Egress Access Control) - support for Per-Stream Filtering and Policing (802.1Q, 8.6.5.1) - Ethernet embedded switches: - Marvell (mv88e6xxx): - add MAB (port auth) offload support - enable PTP receive for mv88e6390 - NXP (ocelot): - support MAC Merge layer - support for the the vsc7512 internal copper phys - Microchip: - lan9303: convert to PHYLINK - lan966x: support TC flower filter statistics - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x - lan937x: support Credit Based Shaper configuration - ksz9477: support Energy Efficient Ethernet - other: - qca8k: convert to regmap read/write API, use bulk operations - rswitch: Improve TX timestamp accuracy - Intel WiFi (iwlwifi): - EHT (Wi-Fi 7) rate reporting - STEP equalizer support: transfer some STEP (connection to radio on platforms with integrated wifi) related parameters from the BIOS to the firmware. - Qualcomm 802.11ax WiFi (ath11k): - IPQ5018 support - Fine Timing Measurement (FTM) responder role support - channel 177 support - MediaTek WiFi (mt76): - per-PHY LED support - mt7996: EHT (Wi-Fi 7) support - Wireless Ethernet Dispatch (WED) reset support - switch to using page pool allocator - RealTek WiFi (rtw89): - support new version of Bluetooth co-existance - Mobile: - rmnet: support TX aggregation" * tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits) page_pool: add a comment explaining the fragment counter usage net: ethtool: fix __ethtool_dev_mm_supported() implementation ethtool: pse-pd: Fix double word in comments xsk: add linux/vmalloc.h to xsk.c sefltests: netdevsim: wait for devlink instance after netns removal selftest: fib_tests: Always cleanup before exit net/mlx5e: Align IPsec ASO result memory to be as required by hardware net/mlx5e: TC, Set CT miss to the specific ct action instance net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG net/mlx5: Refactor tc miss handling to a single function net/mlx5: Kconfig: Make tc offload depend on tc skb extension net/sched: flower: Support hardware miss to tc action net/sched: flower: Move filter handle initialization earlier net/sched: cls_api: Support hardware miss to tc action net/sched: Rename user cookie and act cookie sfc: fix builds without CONFIG_RTC_LIB sfc: clean up some inconsistent indentings net/mlx4_en: Introduce flexible array to silence overflow warning net: lan966x: Fix possible deadlock inside PTP net/ulp: Remove redundant ->clone() test in inet_clone_ulp(). ...
Diffstat (limited to 'kernel/jump_label.c')
-rw-r--r--kernel/jump_label.c867
1 files changed, 867 insertions, 0 deletions
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
new file mode 100644
index 000000000..d9c822bbf
--- /dev/null
+++ b/kernel/jump_label.c
@@ -0,0 +1,867 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * jump label support
+ *
+ * Copyright (C) 2009 Jason Baron <jbaron@redhat.com>
+ * Copyright (C) 2011 Peter Zijlstra
+ *
+ */
+#include <linux/memory.h>
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/sort.h>
+#include <linux/err.h>
+#include <linux/static_key.h>
+#include <linux/jump_label_ratelimit.h>
+#include <linux/bug.h>
+#include <linux/cpu.h>
+#include <asm/sections.h>
+
+/* mutex to protect coming/going of the jump_label table */
+static DEFINE_MUTEX(jump_label_mutex);
+
+void jump_label_lock(void)
+{
+ mutex_lock(&jump_label_mutex);
+}
+
+void jump_label_unlock(void)
+{
+ mutex_unlock(&jump_label_mutex);
+}
+
+static int jump_label_cmp(const void *a, const void *b)
+{
+ const struct jump_entry *jea = a;
+ const struct jump_entry *jeb = b;
+
+ /*
+ * Entrires are sorted by key.
+ */
+ if (jump_entry_key(jea) < jump_entry_key(jeb))
+ return -1;
+
+ if (jump_entry_key(jea) > jump_entry_key(jeb))
+ return 1;
+
+ /*
+ * In the batching mode, entries should also be sorted by the code
+ * inside the already sorted list of entries, enabling a bsearch in
+ * the vector.
+ */
+ if (jump_entry_code(jea) < jump_entry_code(jeb))
+ return -1;
+
+ if (jump_entry_code(jea) > jump_entry_code(jeb))
+ return 1;
+
+ return 0;
+}
+
+static void jump_label_swap(void *a, void *b, int size)
+{
+ long delta = (unsigned long)a - (unsigned long)b;
+ struct jump_entry *jea = a;
+ struct jump_entry *jeb = b;
+ struct jump_entry tmp = *jea;
+
+ jea->code = jeb->code - delta;
+ jea->target = jeb->target - delta;
+ jea->key = jeb->key - delta;
+
+ jeb->code = tmp.code + delta;
+ jeb->target = tmp.target + delta;
+ jeb->key = tmp.key + delta;
+}
+
+static void
+jump_label_sort_entries(struct jump_entry *start, struct jump_entry *stop)
+{
+ unsigned long size;
+ void *swapfn = NULL;
+
+ if (IS_ENABLED(CONFIG_HAVE_ARCH_JUMP_LABEL_RELATIVE))
+ swapfn = jump_label_swap;
+
+ size = (((unsigned long)stop - (unsigned long)start)
+ / sizeof(struct jump_entry));
+ sort(start, size, sizeof(struct jump_entry), jump_label_cmp, swapfn);
+}
+
+static void jump_label_update(struct static_key *key);
+
+/*
+ * There are similar definitions for the !CONFIG_JUMP_LABEL case in jump_label.h.
+ * The use of 'atomic_read()' requires atomic.h and its problematic for some
+ * kernel headers such as kernel.h and others. Since static_key_count() is not
+ * used in the branch statements as it is for the !CONFIG_JUMP_LABEL case its ok
+ * to have it be a function here. Similarly, for 'static_key_enable()' and
+ * 'static_key_disable()', which require bug.h. This should allow jump_label.h
+ * to be included from most/all places for CONFIG_JUMP_LABEL.
+ */
+int static_key_count(struct static_key *key)
+{
+ /*
+ * -1 means the first static_key_slow_inc() is in progress.
+ * static_key_enabled() must return true, so return 1 here.
+ */
+ int n = atomic_read(&key->enabled);
+
+ return n >= 0 ? n : 1;
+}
+EXPORT_SYMBOL_GPL(static_key_count);
+
+/*
+ * static_key_fast_inc_not_disabled - adds a user for a static key
+ * @key: static key that must be already enabled
+ *
+ * The caller must make sure that the static key can't get disabled while
+ * in this function. It doesn't patch jump labels, only adds a user to
+ * an already enabled static key.
+ *
+ * Returns true if the increment was done. Unlike refcount_t the ref counter
+ * is not saturated, but will fail to increment on overflow.
+ */
+bool static_key_fast_inc_not_disabled(struct static_key *key)
+{
+ int v;
+
+ STATIC_KEY_CHECK_USE(key);
+ /*
+ * Negative key->enabled has a special meaning: it sends
+ * static_key_slow_inc() down the slow path, and it is non-zero
+ * so it counts as "enabled" in jump_label_update(). Note that
+ * atomic_inc_unless_negative() checks >= 0, so roll our own.
+ */
+ v = atomic_read(&key->enabled);
+ do {
+ if (v <= 0 || (v + 1) < 0)
+ return false;
+ } while (!likely(atomic_try_cmpxchg(&key->enabled, &v, v + 1)));
+
+ return true;
+}
+EXPORT_SYMBOL_GPL(static_key_fast_inc_not_disabled);
+
+bool static_key_slow_inc_cpuslocked(struct static_key *key)
+{
+ lockdep_assert_cpus_held();
+
+ /*
+ * Careful if we get concurrent static_key_slow_inc() calls;
+ * later calls must wait for the first one to _finish_ the
+ * jump_label_update() process. At the same time, however,
+ * the jump_label_update() call below wants to see
+ * static_key_enabled(&key) for jumps to be updated properly.
+ */
+ if (static_key_fast_inc_not_disabled(key))
+ return true;
+
+ jump_label_lock();
+ if (atomic_read(&key->enabled) == 0) {
+ atomic_set(&key->enabled, -1);
+ jump_label_update(key);
+ /*
+ * Ensure that if the above cmpxchg loop observes our positive
+ * value, it must also observe all the text changes.
+ */
+ atomic_set_release(&key->enabled, 1);
+ } else {
+ if (WARN_ON_ONCE(!static_key_fast_inc_not_disabled(key))) {
+ jump_label_unlock();
+ return false;
+ }
+ }
+ jump_label_unlock();
+ return true;
+}
+
+bool static_key_slow_inc(struct static_key *key)
+{
+ bool ret;
+
+ cpus_read_lock();
+ ret = static_key_slow_inc_cpuslocked(key);
+ cpus_read_unlock();
+ return ret;
+}
+EXPORT_SYMBOL_GPL(static_key_slow_inc);
+
+void static_key_enable_cpuslocked(struct static_key *key)
+{
+ STATIC_KEY_CHECK_USE(key);
+ lockdep_assert_cpus_held();
+
+ if (atomic_read(&key->enabled) > 0) {
+ WARN_ON_ONCE(atomic_read(&key->enabled) != 1);
+ return;
+ }
+
+ jump_label_lock();
+ if (atomic_read(&key->enabled) == 0) {
+ atomic_set(&key->enabled, -1);
+ jump_label_update(key);
+ /*
+ * See static_key_slow_inc().
+ */
+ atomic_set_release(&key->enabled, 1);
+ }
+ jump_label_unlock();
+}
+EXPORT_SYMBOL_GPL(static_key_enable_cpuslocked);
+
+void static_key_enable(struct static_key *key)
+{
+ cpus_read_lock();
+ static_key_enable_cpuslocked(key);
+ cpus_read_unlock();
+}
+EXPORT_SYMBOL_GPL(static_key_enable);
+
+void static_key_disable_cpuslocked(struct static_key *key)
+{
+ STATIC_KEY_CHECK_USE(key);
+ lockdep_assert_cpus_held();
+
+ if (atomic_read(&key->enabled) != 1) {
+ WARN_ON_ONCE(atomic_read(&key->enabled) != 0);
+ return;
+ }
+
+ jump_label_lock();
+ if (atomic_cmpxchg(&key->enabled, 1, 0))
+ jump_label_update(key);
+ jump_label_unlock();
+}
+EXPORT_SYMBOL_GPL(static_key_disable_cpuslocked);
+
+void static_key_disable(struct static_key *key)
+{
+ cpus_read_lock();
+ static_key_disable_cpuslocked(key);
+ cpus_read_unlock();
+}
+EXPORT_SYMBOL_GPL(static_key_disable);
+
+static bool static_key_slow_try_dec(struct static_key *key)
+{
+ int val;
+
+ val = atomic_fetch_add_unless(&key->enabled, -1, 1);
+ if (val == 1)
+ return false;
+
+ /*
+ * The negative count check is valid even when a negative
+ * key->enabled is in use by static_key_slow_inc(); a
+ * __static_key_slow_dec() before the first static_key_slow_inc()
+ * returns is unbalanced, because all other static_key_slow_inc()
+ * instances block while the update is in progress.
+ */
+ WARN(val < 0, "jump label: negative count!\n");
+ return true;
+}
+
+static void __static_key_slow_dec_cpuslocked(struct static_key *key)
+{
+ lockdep_assert_cpus_held();
+
+ if (static_key_slow_try_dec(key))
+ return;
+
+ jump_label_lock();
+ if (atomic_dec_and_test(&key->enabled))
+ jump_label_update(key);
+ jump_label_unlock();
+}
+
+static void __static_key_slow_dec(struct static_key *key)
+{
+ cpus_read_lock();
+ __static_key_slow_dec_cpuslocked(key);
+ cpus_read_unlock();
+}
+
+void jump_label_update_timeout(struct work_struct *work)
+{
+ struct static_key_deferred *key =
+ container_of(work, struct static_key_deferred, work.work);
+ __static_key_slow_dec(&key->key);
+}
+EXPORT_SYMBOL_GPL(jump_label_update_timeout);
+
+void static_key_slow_dec(struct static_key *key)
+{
+ STATIC_KEY_CHECK_USE(key);
+ __static_key_slow_dec(key);
+}
+EXPORT_SYMBOL_GPL(static_key_slow_dec);
+
+void static_key_slow_dec_cpuslocked(struct static_key *key)
+{
+ STATIC_KEY_CHECK_USE(key);
+ __static_key_slow_dec_cpuslocked(key);
+}
+
+void __static_key_slow_dec_deferred(struct static_key *key,
+ struct delayed_work *work,
+ unsigned long timeout)
+{
+ STATIC_KEY_CHECK_USE(key);
+
+ if (static_key_slow_try_dec(key))
+ return;
+
+ schedule_delayed_work(work, timeout);
+}
+EXPORT_SYMBOL_GPL(__static_key_slow_dec_deferred);
+
+void __static_key_deferred_flush(void *key, struct delayed_work *work)
+{
+ STATIC_KEY_CHECK_USE(key);
+ flush_delayed_work(work);
+}
+EXPORT_SYMBOL_GPL(__static_key_deferred_flush);
+
+void jump_label_rate_limit(struct static_key_deferred *key,
+ unsigned long rl)
+{
+ STATIC_KEY_CHECK_USE(key);
+ key->timeout = rl;
+ INIT_DELAYED_WORK(&key->work, jump_label_update_timeout);
+}
+EXPORT_SYMBOL_GPL(jump_label_rate_limit);
+
+static int addr_conflict(struct jump_entry *entry, void *start, void *end)
+{
+ if (jump_entry_code(entry) <= (unsigned long)end &&
+ jump_entry_code(entry) + jump_entry_size(entry) > (unsigned long)start)
+ return 1;
+
+ return 0;
+}
+
+static int __jump_label_text_reserved(struct jump_entry *iter_start,
+ struct jump_entry *iter_stop, void *start, void *end, bool init)
+{
+ struct jump_entry *iter;
+
+ iter = iter_start;
+ while (iter < iter_stop) {
+ if (init || !jump_entry_is_init(iter)) {
+ if (addr_conflict(iter, start, end))
+ return 1;
+ }
+ iter++;
+ }
+
+ return 0;
+}
+
+#ifndef arch_jump_label_transform_static
+static void arch_jump_label_transform_static(struct jump_entry *entry,
+ enum jump_label_type type)
+{
+ /* nothing to do on most architectures */
+}
+#endif
+
+static inline struct jump_entry *static_key_entries(struct static_key *key)
+{
+ WARN_ON_ONCE(key->type & JUMP_TYPE_LINKED);
+ return (struct jump_entry *)(key->type & ~JUMP_TYPE_MASK);
+}
+
+static inline bool static_key_type(struct static_key *key)
+{
+ return key->type & JUMP_TYPE_TRUE;
+}
+
+static inline bool static_key_linked(struct static_key *key)
+{
+ return key->type & JUMP_TYPE_LINKED;
+}
+
+static inline void static_key_clear_linked(struct static_key *key)
+{
+ key->type &= ~JUMP_TYPE_LINKED;
+}
+
+static inline void static_key_set_linked(struct static_key *key)
+{
+ key->type |= JUMP_TYPE_LINKED;
+}
+
+/***
+ * A 'struct static_key' uses a union such that it either points directly
+ * to a table of 'struct jump_entry' or to a linked list of modules which in
+ * turn point to 'struct jump_entry' tables.
+ *
+ * The two lower bits of the pointer are used to keep track of which pointer
+ * type is in use and to store the initial branch direction, we use an access
+ * function which preserves these bits.
+ */
+static void static_key_set_entries(struct static_key *key,
+ struct jump_entry *entries)
+{
+ unsigned long type;
+
+ WARN_ON_ONCE((unsigned long)entries & JUMP_TYPE_MASK);
+ type = key->type & JUMP_TYPE_MASK;
+ key->entries = entries;
+ key->type |= type;
+}
+
+static enum jump_label_type jump_label_type(struct jump_entry *entry)
+{
+ struct static_key *key = jump_entry_key(entry);
+ bool enabled = static_key_enabled(key);
+ bool branch = jump_entry_is_branch(entry);
+
+ /* See the comment in linux/jump_label.h */
+ return enabled ^ branch;
+}
+
+static bool jump_label_can_update(struct jump_entry *entry, bool init)
+{
+ /*
+ * Cannot update code that was in an init text area.
+ */
+ if (!init && jump_entry_is_init(entry))
+ return false;
+
+ if (!kernel_text_address(jump_entry_code(entry))) {
+ /*
+ * This skips patching built-in __exit, which
+ * is part of init_section_contains() but is
+ * not part of kernel_text_address().
+ *
+ * Skipping built-in __exit is fine since it
+ * will never be executed.
+ */
+ WARN_ONCE(!jump_entry_is_init(entry),
+ "can't patch jump_label at %pS",
+ (void *)jump_entry_code(entry));
+ return false;
+ }
+
+ return true;
+}
+
+#ifndef HAVE_JUMP_LABEL_BATCH
+static void __jump_label_update(struct static_key *key,
+ struct jump_entry *entry,
+ struct jump_entry *stop,
+ bool init)
+{
+ for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) {
+ if (jump_label_can_update(entry, init))
+ arch_jump_label_transform(entry, jump_label_type(entry));
+ }
+}
+#else
+static void __jump_label_update(struct static_key *key,
+ struct jump_entry *entry,
+ struct jump_entry *stop,
+ bool init)
+{
+ for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) {
+
+ if (!jump_label_can_update(entry, init))
+ continue;
+
+ if (!arch_jump_label_transform_queue(entry, jump_label_type(entry))) {
+ /*
+ * Queue is full: Apply the current queue and try again.
+ */
+ arch_jump_label_transform_apply();
+ BUG_ON(!arch_jump_label_transform_queue(entry, jump_label_type(entry)));
+ }
+ }
+ arch_jump_label_transform_apply();
+}
+#endif
+
+void __init jump_label_init(void)
+{
+ struct jump_entry *iter_start = __start___jump_table;
+ struct jump_entry *iter_stop = __stop___jump_table;
+ struct static_key *key = NULL;
+ struct jump_entry *iter;
+
+ /*
+ * Since we are initializing the static_key.enabled field with
+ * with the 'raw' int values (to avoid pulling in atomic.h) in
+ * jump_label.h, let's make sure that is safe. There are only two
+ * cases to check since we initialize to 0 or 1.
+ */
+ BUILD_BUG_ON((int)ATOMIC_INIT(0) != 0);
+ BUILD_BUG_ON((int)ATOMIC_INIT(1) != 1);
+
+ if (static_key_initialized)
+ return;
+
+ cpus_read_lock();
+ jump_label_lock();
+ jump_label_sort_entries(iter_start, iter_stop);
+
+ for (iter = iter_start; iter < iter_stop; iter++) {
+ struct static_key *iterk;
+ bool in_init;
+
+ /* rewrite NOPs */
+ if (jump_label_type(iter) == JUMP_LABEL_NOP)
+ arch_jump_label_transform_static(iter, JUMP_LABEL_NOP);
+
+ in_init = init_section_contains((void *)jump_entry_code(iter), 1);
+ jump_entry_set_init(iter, in_init);
+
+ iterk = jump_entry_key(iter);
+ if (iterk == key)
+ continue;
+
+ key = iterk;
+ static_key_set_entries(key, iter);
+ }
+ static_key_initialized = true;
+ jump_label_unlock();
+ cpus_read_unlock();
+}
+
+#ifdef CONFIG_MODULES
+
+enum jump_label_type jump_label_init_type(struct jump_entry *entry)
+{
+ struct static_key *key = jump_entry_key(entry);
+ bool type = static_key_type(key);
+ bool branch = jump_entry_is_branch(entry);
+
+ /* See the comment in linux/jump_label.h */
+ return type ^ branch;
+}
+
+struct static_key_mod {
+ struct static_key_mod *next;
+ struct jump_entry *entries;
+ struct module *mod;
+};
+
+static inline struct static_key_mod *static_key_mod(struct static_key *key)
+{
+ WARN_ON_ONCE(!static_key_linked(key));
+ return (struct static_key_mod *)(key->type & ~JUMP_TYPE_MASK);
+}
+
+/***
+ * key->type and key->next are the same via union.
+ * This sets key->next and preserves the type bits.
+ *
+ * See additional comments above static_key_set_entries().
+ */
+static void static_key_set_mod(struct static_key *key,
+ struct static_key_mod *mod)
+{
+ unsigned long type;
+
+ WARN_ON_ONCE((unsigned long)mod & JUMP_TYPE_MASK);
+ type = key->type & JUMP_TYPE_MASK;
+ key->next = mod;
+ key->type |= type;
+}
+
+static int __jump_label_mod_text_reserved(void *start, void *end)
+{
+ struct module *mod;
+ int ret;
+
+ preempt_disable();
+ mod = __module_text_address((unsigned long)start);
+ WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);
+ if (!try_module_get(mod))
+ mod = NULL;
+ preempt_enable();
+
+ if (!mod)
+ return 0;
+
+ ret = __jump_label_text_reserved(mod->jump_entries,
+ mod->jump_entries + mod->num_jump_entries,
+ start, end, mod->state == MODULE_STATE_COMING);
+
+ module_put(mod);
+
+ return ret;
+}
+
+static void __jump_label_mod_update(struct static_key *key)
+{
+ struct static_key_mod *mod;
+
+ for (mod = static_key_mod(key); mod; mod = mod->next) {
+ struct jump_entry *stop;
+ struct module *m;
+
+ /*
+ * NULL if the static_key is defined in a module
+ * that does not use it
+ */
+ if (!mod->entries)
+ continue;
+
+ m = mod->mod;
+ if (!m)
+ stop = __stop___jump_table;
+ else
+ stop = m->jump_entries + m->num_jump_entries;
+ __jump_label_update(key, mod->entries, stop,
+ m && m->state == MODULE_STATE_COMING);
+ }
+}
+
+static int jump_label_add_module(struct module *mod)
+{
+ struct jump_entry *iter_start = mod->jump_entries;
+ struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
+ struct jump_entry *iter;
+ struct static_key *key = NULL;
+ struct static_key_mod *jlm, *jlm2;
+
+ /* if the module doesn't have jump label entries, just return */
+ if (iter_start == iter_stop)
+ return 0;
+
+ jump_label_sort_entries(iter_start, iter_stop);
+
+ for (iter = iter_start; iter < iter_stop; iter++) {
+ struct static_key *iterk;
+ bool in_init;
+
+ in_init = within_module_init(jump_entry_code(iter), mod);
+ jump_entry_set_init(iter, in_init);
+
+ iterk = jump_entry_key(iter);
+ if (iterk == key)
+ continue;
+
+ key = iterk;
+ if (within_module((unsigned long)key, mod)) {
+ static_key_set_entries(key, iter);
+ continue;
+ }
+ jlm = kzalloc(sizeof(struct static_key_mod), GFP_KERNEL);
+ if (!jlm)
+ return -ENOMEM;
+ if (!static_key_linked(key)) {
+ jlm2 = kzalloc(sizeof(struct static_key_mod),
+ GFP_KERNEL);
+ if (!jlm2) {
+ kfree(jlm);
+ return -ENOMEM;
+ }
+ preempt_disable();
+ jlm2->mod = __module_address((unsigned long)key);
+ preempt_enable();
+ jlm2->entries = static_key_entries(key);
+ jlm2->next = NULL;
+ static_key_set_mod(key, jlm2);
+ static_key_set_linked(key);
+ }
+ jlm->mod = mod;
+ jlm->entries = iter;
+ jlm->next = static_key_mod(key);
+ static_key_set_mod(key, jlm);
+ static_key_set_linked(key);
+
+ /* Only update if we've changed from our initial state */
+ if (jump_label_type(iter) != jump_label_init_type(iter))
+ __jump_label_update(key, iter, iter_stop, true);
+ }
+
+ return 0;
+}
+
+static void jump_label_del_module(struct module *mod)
+{
+ struct jump_entry *iter_start = mod->jump_entries;
+ struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
+ struct jump_entry *iter;
+ struct static_key *key = NULL;
+ struct static_key_mod *jlm, **prev;
+
+ for (iter = iter_start; iter < iter_stop; iter++) {
+ if (jump_entry_key(iter) == key)
+ continue;
+
+ key = jump_entry_key(iter);
+
+ if (within_module((unsigned long)key, mod))
+ continue;
+
+ /* No memory during module load */
+ if (WARN_ON(!static_key_linked(key)))
+ continue;
+
+ prev = &key->next;
+ jlm = static_key_mod(key);
+
+ while (jlm && jlm->mod != mod) {
+ prev = &jlm->next;
+ jlm = jlm->next;
+ }
+
+ /* No memory during module load */
+ if (WARN_ON(!jlm))
+ continue;
+
+ if (prev == &key->next)
+ static_key_set_mod(key, jlm->next);
+ else
+ *prev = jlm->next;
+
+ kfree(jlm);
+
+ jlm = static_key_mod(key);
+ /* if only one etry is left, fold it back into the static_key */
+ if (jlm->next == NULL) {
+ static_key_set_entries(key, jlm->entries);
+ static_key_clear_linked(key);
+ kfree(jlm);
+ }
+ }
+}
+
+static int
+jump_label_module_notify(struct notifier_block *self, unsigned long val,
+ void *data)
+{
+ struct module *mod = data;
+ int ret = 0;
+
+ cpus_read_lock();
+ jump_label_lock();
+
+ switch (val) {
+ case MODULE_STATE_COMING:
+ ret = jump_label_add_module(mod);
+ if (ret) {
+ WARN(1, "Failed to allocate memory: jump_label may not work properly.\n");
+ jump_label_del_module(mod);
+ }
+ break;
+ case MODULE_STATE_GOING:
+ jump_label_del_module(mod);
+ break;
+ }
+
+ jump_label_unlock();
+ cpus_read_unlock();
+
+ return notifier_from_errno(ret);
+}
+
+static struct notifier_block jump_label_module_nb = {
+ .notifier_call = jump_label_module_notify,
+ .priority = 1, /* higher than tracepoints */
+};
+
+static __init int jump_label_init_module(void)
+{
+ return register_module_notifier(&jump_label_module_nb);
+}
+early_initcall(jump_label_init_module);
+
+#endif /* CONFIG_MODULES */
+
+/***
+ * jump_label_text_reserved - check if addr range is reserved
+ * @start: start text addr
+ * @end: end text addr
+ *
+ * checks if the text addr located between @start and @end
+ * overlaps with any of the jump label patch addresses. Code
+ * that wants to modify kernel text should first verify that
+ * it does not overlap with any of the jump label addresses.
+ * Caller must hold jump_label_mutex.
+ *
+ * returns 1 if there is an overlap, 0 otherwise
+ */
+int jump_label_text_reserved(void *start, void *end)
+{
+ bool init = system_state < SYSTEM_RUNNING;
+ int ret = __jump_label_text_reserved(__start___jump_table,
+ __stop___jump_table, start, end, init);
+
+ if (ret)
+ return ret;
+
+#ifdef CONFIG_MODULES
+ ret = __jump_label_mod_text_reserved(start, end);
+#endif
+ return ret;
+}
+
+static void jump_label_update(struct static_key *key)
+{
+ struct jump_entry *stop = __stop___jump_table;
+ bool init = system_state < SYSTEM_RUNNING;
+ struct jump_entry *entry;
+#ifdef CONFIG_MODULES
+ struct module *mod;
+
+ if (static_key_linked(key)) {
+ __jump_label_mod_update(key);
+ return;
+ }
+
+ preempt_disable();
+ mod = __module_address((unsigned long)key);
+ if (mod) {
+ stop = mod->jump_entries + mod->num_jump_entries;
+ init = mod->state == MODULE_STATE_COMING;
+ }
+ preempt_enable();
+#endif
+ entry = static_key_entries(key);
+ /* if there are no users, entry can be NULL */
+ if (entry)
+ __jump_label_update(key, entry, stop, init);
+}
+
+#ifdef CONFIG_STATIC_KEYS_SELFTEST
+static DEFINE_STATIC_KEY_TRUE(sk_true);
+static DEFINE_STATIC_KEY_FALSE(sk_false);
+
+static __init int jump_label_test(void)
+{
+ int i;
+
+ for (i = 0; i < 2; i++) {
+ WARN_ON(static_key_enabled(&sk_true.key) != true);
+ WARN_ON(static_key_enabled(&sk_false.key) != false);
+
+ WARN_ON(!static_branch_likely(&sk_true));
+ WARN_ON(!static_branch_unlikely(&sk_true));
+ WARN_ON(static_branch_likely(&sk_false));
+ WARN_ON(static_branch_unlikely(&sk_false));
+
+ static_branch_disable(&sk_true);
+ static_branch_enable(&sk_false);
+
+ WARN_ON(static_key_enabled(&sk_true.key) == true);
+ WARN_ON(static_key_enabled(&sk_false.key) == false);
+
+ WARN_ON(static_branch_likely(&sk_true));
+ WARN_ON(static_branch_unlikely(&sk_true));
+ WARN_ON(!static_branch_likely(&sk_false));
+ WARN_ON(!static_branch_unlikely(&sk_false));
+
+ static_branch_enable(&sk_true);
+ static_branch_disable(&sk_false);
+ }
+
+ return 0;
+}
+early_initcall(jump_label_test);
+#endif /* STATIC_KEYS_SELFTEST */