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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 /arch/riscv/mm/context.c
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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 '')
-rw-r--r--arch/riscv/mm/context.c336
1 files changed, 336 insertions, 0 deletions
diff --git a/arch/riscv/mm/context.c b/arch/riscv/mm/context.c
new file mode 100644
index 000000000..80ce9caba
--- /dev/null
+++ b/arch/riscv/mm/context.c
@@ -0,0 +1,336 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2012 Regents of the University of California
+ * Copyright (C) 2017 SiFive
+ * Copyright (C) 2021 Western Digital Corporation or its affiliates.
+ */
+
+#include <linux/bitops.h>
+#include <linux/cpumask.h>
+#include <linux/mm.h>
+#include <linux/percpu.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/static_key.h>
+#include <asm/tlbflush.h>
+#include <asm/cacheflush.h>
+#include <asm/mmu_context.h>
+
+#ifdef CONFIG_MMU
+
+DEFINE_STATIC_KEY_FALSE(use_asid_allocator);
+
+static unsigned long asid_bits;
+static unsigned long num_asids;
+static unsigned long asid_mask;
+
+static atomic_long_t current_version;
+
+static DEFINE_RAW_SPINLOCK(context_lock);
+static cpumask_t context_tlb_flush_pending;
+static unsigned long *context_asid_map;
+
+static DEFINE_PER_CPU(atomic_long_t, active_context);
+static DEFINE_PER_CPU(unsigned long, reserved_context);
+
+static bool check_update_reserved_context(unsigned long cntx,
+ unsigned long newcntx)
+{
+ int cpu;
+ bool hit = false;
+
+ /*
+ * Iterate over the set of reserved CONTEXT looking for a match.
+ * If we find one, then we can update our mm to use new CONTEXT
+ * (i.e. the same CONTEXT in the current_version) but we can't
+ * exit the loop early, since we need to ensure that all copies
+ * of the old CONTEXT are updated to reflect the mm. Failure to do
+ * so could result in us missing the reserved CONTEXT in a future
+ * version.
+ */
+ for_each_possible_cpu(cpu) {
+ if (per_cpu(reserved_context, cpu) == cntx) {
+ hit = true;
+ per_cpu(reserved_context, cpu) = newcntx;
+ }
+ }
+
+ return hit;
+}
+
+static void __flush_context(void)
+{
+ int i;
+ unsigned long cntx;
+
+ /* Must be called with context_lock held */
+ lockdep_assert_held(&context_lock);
+
+ /* Update the list of reserved ASIDs and the ASID bitmap. */
+ bitmap_clear(context_asid_map, 0, num_asids);
+
+ /* Mark already active ASIDs as used */
+ for_each_possible_cpu(i) {
+ cntx = atomic_long_xchg_relaxed(&per_cpu(active_context, i), 0);
+ /*
+ * If this CPU has already been through a rollover, but
+ * hasn't run another task in the meantime, we must preserve
+ * its reserved CONTEXT, as this is the only trace we have of
+ * the process it is still running.
+ */
+ if (cntx == 0)
+ cntx = per_cpu(reserved_context, i);
+
+ __set_bit(cntx & asid_mask, context_asid_map);
+ per_cpu(reserved_context, i) = cntx;
+ }
+
+ /* Mark ASID #0 as used because it is used at boot-time */
+ __set_bit(0, context_asid_map);
+
+ /* Queue a TLB invalidation for each CPU on next context-switch */
+ cpumask_setall(&context_tlb_flush_pending);
+}
+
+static unsigned long __new_context(struct mm_struct *mm)
+{
+ static u32 cur_idx = 1;
+ unsigned long cntx = atomic_long_read(&mm->context.id);
+ unsigned long asid, ver = atomic_long_read(&current_version);
+
+ /* Must be called with context_lock held */
+ lockdep_assert_held(&context_lock);
+
+ if (cntx != 0) {
+ unsigned long newcntx = ver | (cntx & asid_mask);
+
+ /*
+ * If our current CONTEXT was active during a rollover, we
+ * can continue to use it and this was just a false alarm.
+ */
+ if (check_update_reserved_context(cntx, newcntx))
+ return newcntx;
+
+ /*
+ * We had a valid CONTEXT in a previous life, so try to
+ * re-use it if possible.
+ */
+ if (!__test_and_set_bit(cntx & asid_mask, context_asid_map))
+ return newcntx;
+ }
+
+ /*
+ * Allocate a free ASID. If we can't find one then increment
+ * current_version and flush all ASIDs.
+ */
+ asid = find_next_zero_bit(context_asid_map, num_asids, cur_idx);
+ if (asid != num_asids)
+ goto set_asid;
+
+ /* We're out of ASIDs, so increment current_version */
+ ver = atomic_long_add_return_relaxed(num_asids, &current_version);
+
+ /* Flush everything */
+ __flush_context();
+
+ /* We have more ASIDs than CPUs, so this will always succeed */
+ asid = find_next_zero_bit(context_asid_map, num_asids, 1);
+
+set_asid:
+ __set_bit(asid, context_asid_map);
+ cur_idx = asid;
+ return asid | ver;
+}
+
+static void set_mm_asid(struct mm_struct *mm, unsigned int cpu)
+{
+ unsigned long flags;
+ bool need_flush_tlb = false;
+ unsigned long cntx, old_active_cntx;
+
+ cntx = atomic_long_read(&mm->context.id);
+
+ /*
+ * If our active_context is non-zero and the context matches the
+ * current_version, then we update the active_context entry with a
+ * relaxed cmpxchg.
+ *
+ * Following is how we handle racing with a concurrent rollover:
+ *
+ * - We get a zero back from the cmpxchg and end up waiting on the
+ * lock. Taking the lock synchronises with the rollover and so
+ * we are forced to see the updated verion.
+ *
+ * - We get a valid context back from the cmpxchg then we continue
+ * using old ASID because __flush_context() would have marked ASID
+ * of active_context as used and next context switch we will
+ * allocate new context.
+ */
+ old_active_cntx = atomic_long_read(&per_cpu(active_context, cpu));
+ if (old_active_cntx &&
+ ((cntx & ~asid_mask) == atomic_long_read(&current_version)) &&
+ atomic_long_cmpxchg_relaxed(&per_cpu(active_context, cpu),
+ old_active_cntx, cntx))
+ goto switch_mm_fast;
+
+ raw_spin_lock_irqsave(&context_lock, flags);
+
+ /* Check that our ASID belongs to the current_version. */
+ cntx = atomic_long_read(&mm->context.id);
+ if ((cntx & ~asid_mask) != atomic_long_read(&current_version)) {
+ cntx = __new_context(mm);
+ atomic_long_set(&mm->context.id, cntx);
+ }
+
+ if (cpumask_test_and_clear_cpu(cpu, &context_tlb_flush_pending))
+ need_flush_tlb = true;
+
+ atomic_long_set(&per_cpu(active_context, cpu), cntx);
+
+ raw_spin_unlock_irqrestore(&context_lock, flags);
+
+switch_mm_fast:
+ csr_write(CSR_SATP, virt_to_pfn(mm->pgd) |
+ ((cntx & asid_mask) << SATP_ASID_SHIFT) |
+ satp_mode);
+
+ if (need_flush_tlb)
+ local_flush_tlb_all();
+#ifdef CONFIG_SMP
+ else {
+ cpumask_t *mask = &mm->context.tlb_stale_mask;
+
+ if (cpumask_test_cpu(cpu, mask)) {
+ cpumask_clear_cpu(cpu, mask);
+ local_flush_tlb_all_asid(cntx & asid_mask);
+ }
+ }
+#endif
+}
+
+static void set_mm_noasid(struct mm_struct *mm)
+{
+ /* Switch the page table and blindly nuke entire local TLB */
+ csr_write(CSR_SATP, virt_to_pfn(mm->pgd) | satp_mode);
+ local_flush_tlb_all();
+}
+
+static inline void set_mm(struct mm_struct *mm, unsigned int cpu)
+{
+ if (static_branch_unlikely(&use_asid_allocator))
+ set_mm_asid(mm, cpu);
+ else
+ set_mm_noasid(mm);
+}
+
+static int __init asids_init(void)
+{
+ unsigned long old;
+
+ /* Figure-out number of ASID bits in HW */
+ old = csr_read(CSR_SATP);
+ asid_bits = old | (SATP_ASID_MASK << SATP_ASID_SHIFT);
+ csr_write(CSR_SATP, asid_bits);
+ asid_bits = (csr_read(CSR_SATP) >> SATP_ASID_SHIFT) & SATP_ASID_MASK;
+ asid_bits = fls_long(asid_bits);
+ csr_write(CSR_SATP, old);
+
+ /*
+ * In the process of determining number of ASID bits (above)
+ * we polluted the TLB of current HART so let's do TLB flushed
+ * to remove unwanted TLB enteries.
+ */
+ local_flush_tlb_all();
+
+ /* Pre-compute ASID details */
+ if (asid_bits) {
+ num_asids = 1 << asid_bits;
+ asid_mask = num_asids - 1;
+ }
+
+ /*
+ * Use ASID allocator only if number of HW ASIDs are
+ * at-least twice more than CPUs
+ */
+ if (num_asids > (2 * num_possible_cpus())) {
+ atomic_long_set(&current_version, num_asids);
+
+ context_asid_map = bitmap_zalloc(num_asids, GFP_KERNEL);
+ if (!context_asid_map)
+ panic("Failed to allocate bitmap for %lu ASIDs\n",
+ num_asids);
+
+ __set_bit(0, context_asid_map);
+
+ static_branch_enable(&use_asid_allocator);
+
+ pr_info("ASID allocator using %lu bits (%lu entries)\n",
+ asid_bits, num_asids);
+ } else {
+ pr_info("ASID allocator disabled (%lu bits)\n", asid_bits);
+ }
+
+ return 0;
+}
+early_initcall(asids_init);
+#else
+static inline void set_mm(struct mm_struct *mm, unsigned int cpu)
+{
+ /* Nothing to do here when there is no MMU */
+}
+#endif
+
+/*
+ * When necessary, performs a deferred icache flush for the given MM context,
+ * on the local CPU. RISC-V has no direct mechanism for instruction cache
+ * shoot downs, so instead we send an IPI that informs the remote harts they
+ * need to flush their local instruction caches. To avoid pathologically slow
+ * behavior in a common case (a bunch of single-hart processes on a many-hart
+ * machine, ie 'make -j') we avoid the IPIs for harts that are not currently
+ * executing a MM context and instead schedule a deferred local instruction
+ * cache flush to be performed before execution resumes on each hart. This
+ * actually performs that local instruction cache flush, which implicitly only
+ * refers to the current hart.
+ *
+ * The "cpu" argument must be the current local CPU number.
+ */
+static inline void flush_icache_deferred(struct mm_struct *mm, unsigned int cpu)
+{
+#ifdef CONFIG_SMP
+ cpumask_t *mask = &mm->context.icache_stale_mask;
+
+ if (cpumask_test_cpu(cpu, mask)) {
+ cpumask_clear_cpu(cpu, mask);
+ /*
+ * Ensure the remote hart's writes are visible to this hart.
+ * This pairs with a barrier in flush_icache_mm.
+ */
+ smp_mb();
+ local_flush_icache_all();
+ }
+
+#endif
+}
+
+void switch_mm(struct mm_struct *prev, struct mm_struct *next,
+ struct task_struct *task)
+{
+ unsigned int cpu;
+
+ if (unlikely(prev == next))
+ return;
+
+ /*
+ * Mark the current MM context as inactive, and the next as
+ * active. This is at least used by the icache flushing
+ * routines in order to determine who should be flushed.
+ */
+ cpu = smp_processor_id();
+
+ cpumask_clear_cpu(cpu, mm_cpumask(prev));
+ cpumask_set_cpu(cpu, mm_cpumask(next));
+
+ set_mm(next, cpu);
+
+ flush_icache_deferred(next, cpu);
+}