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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/x86/kernel/fpu/core.c
downloadlinux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz
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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 'arch/x86/kernel/fpu/core.c')
-rw-r--r--arch/x86/kernel/fpu/core.c864
1 files changed, 864 insertions, 0 deletions
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
new file mode 100644
index 000000000..caf33486d
--- /dev/null
+++ b/arch/x86/kernel/fpu/core.c
@@ -0,0 +1,864 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 1994 Linus Torvalds
+ *
+ * Pentium III FXSR, SSE support
+ * General FPU state handling cleanups
+ * Gareth Hughes <gareth@valinux.com>, May 2000
+ */
+#include <asm/fpu/api.h>
+#include <asm/fpu/regset.h>
+#include <asm/fpu/sched.h>
+#include <asm/fpu/signal.h>
+#include <asm/fpu/types.h>
+#include <asm/traps.h>
+#include <asm/irq_regs.h>
+
+#include <uapi/asm/kvm.h>
+
+#include <linux/hardirq.h>
+#include <linux/pkeys.h>
+#include <linux/vmalloc.h>
+
+#include "context.h"
+#include "internal.h"
+#include "legacy.h"
+#include "xstate.h"
+
+#define CREATE_TRACE_POINTS
+#include <asm/trace/fpu.h>
+
+#ifdef CONFIG_X86_64
+DEFINE_STATIC_KEY_FALSE(__fpu_state_size_dynamic);
+DEFINE_PER_CPU(u64, xfd_state);
+#endif
+
+/* The FPU state configuration data for kernel and user space */
+struct fpu_state_config fpu_kernel_cfg __ro_after_init;
+struct fpu_state_config fpu_user_cfg __ro_after_init;
+
+/*
+ * Represents the initial FPU state. It's mostly (but not completely) zeroes,
+ * depending on the FPU hardware format:
+ */
+struct fpstate init_fpstate __ro_after_init;
+
+/* Track in-kernel FPU usage */
+static DEFINE_PER_CPU(bool, in_kernel_fpu);
+
+/*
+ * Track which context is using the FPU on the CPU:
+ */
+DEFINE_PER_CPU(struct fpu *, fpu_fpregs_owner_ctx);
+
+/*
+ * Can we use the FPU in kernel mode with the
+ * whole "kernel_fpu_begin/end()" sequence?
+ */
+bool irq_fpu_usable(void)
+{
+ if (WARN_ON_ONCE(in_nmi()))
+ return false;
+
+ /* In kernel FPU usage already active? */
+ if (this_cpu_read(in_kernel_fpu))
+ return false;
+
+ /*
+ * When not in NMI or hard interrupt context, FPU can be used in:
+ *
+ * - Task context except from within fpregs_lock()'ed critical
+ * regions.
+ *
+ * - Soft interrupt processing context which cannot happen
+ * while in a fpregs_lock()'ed critical region.
+ */
+ if (!in_hardirq())
+ return true;
+
+ /*
+ * In hard interrupt context it's safe when soft interrupts
+ * are enabled, which means the interrupt did not hit in
+ * a fpregs_lock()'ed critical region.
+ */
+ return !softirq_count();
+}
+EXPORT_SYMBOL(irq_fpu_usable);
+
+/*
+ * Track AVX512 state use because it is known to slow the max clock
+ * speed of the core.
+ */
+static void update_avx_timestamp(struct fpu *fpu)
+{
+
+#define AVX512_TRACKING_MASK (XFEATURE_MASK_ZMM_Hi256 | XFEATURE_MASK_Hi16_ZMM)
+
+ if (fpu->fpstate->regs.xsave.header.xfeatures & AVX512_TRACKING_MASK)
+ fpu->avx512_timestamp = jiffies;
+}
+
+/*
+ * Save the FPU register state in fpu->fpstate->regs. The register state is
+ * preserved.
+ *
+ * Must be called with fpregs_lock() held.
+ *
+ * The legacy FNSAVE instruction clears all FPU state unconditionally, so
+ * register state has to be reloaded. That might be a pointless exercise
+ * when the FPU is going to be used by another task right after that. But
+ * this only affects 20+ years old 32bit systems and avoids conditionals all
+ * over the place.
+ *
+ * FXSAVE and all XSAVE variants preserve the FPU register state.
+ */
+void save_fpregs_to_fpstate(struct fpu *fpu)
+{
+ if (likely(use_xsave())) {
+ os_xsave(fpu->fpstate);
+ update_avx_timestamp(fpu);
+ return;
+ }
+
+ if (likely(use_fxsr())) {
+ fxsave(&fpu->fpstate->regs.fxsave);
+ return;
+ }
+
+ /*
+ * Legacy FPU register saving, FNSAVE always clears FPU registers,
+ * so we have to reload them from the memory state.
+ */
+ asm volatile("fnsave %[fp]; fwait" : [fp] "=m" (fpu->fpstate->regs.fsave));
+ frstor(&fpu->fpstate->regs.fsave);
+}
+
+void restore_fpregs_from_fpstate(struct fpstate *fpstate, u64 mask)
+{
+ /*
+ * AMD K7/K8 and later CPUs up to Zen don't save/restore
+ * FDP/FIP/FOP unless an exception is pending. Clear the x87 state
+ * here by setting it to fixed values. "m" is a random variable
+ * that should be in L1.
+ */
+ if (unlikely(static_cpu_has_bug(X86_BUG_FXSAVE_LEAK))) {
+ asm volatile(
+ "fnclex\n\t"
+ "emms\n\t"
+ "fildl %P[addr]" /* set F?P to defined value */
+ : : [addr] "m" (fpstate));
+ }
+
+ if (use_xsave()) {
+ /*
+ * Dynamically enabled features are enabled in XCR0, but
+ * usage requires also that the corresponding bits in XFD
+ * are cleared. If the bits are set then using a related
+ * instruction will raise #NM. This allows to do the
+ * allocation of the larger FPU buffer lazy from #NM or if
+ * the task has no permission to kill it which would happen
+ * via #UD if the feature is disabled in XCR0.
+ *
+ * XFD state is following the same life time rules as
+ * XSTATE and to restore state correctly XFD has to be
+ * updated before XRSTORS otherwise the component would
+ * stay in or go into init state even if the bits are set
+ * in fpstate::regs::xsave::xfeatures.
+ */
+ xfd_update_state(fpstate);
+
+ /*
+ * Restoring state always needs to modify all features
+ * which are in @mask even if the current task cannot use
+ * extended features.
+ *
+ * So fpstate->xfeatures cannot be used here, because then
+ * a feature for which the task has no permission but was
+ * used by the previous task would not go into init state.
+ */
+ mask = fpu_kernel_cfg.max_features & mask;
+
+ os_xrstor(fpstate, mask);
+ } else {
+ if (use_fxsr())
+ fxrstor(&fpstate->regs.fxsave);
+ else
+ frstor(&fpstate->regs.fsave);
+ }
+}
+
+void fpu_reset_from_exception_fixup(void)
+{
+ restore_fpregs_from_fpstate(&init_fpstate, XFEATURE_MASK_FPSTATE);
+}
+
+#if IS_ENABLED(CONFIG_KVM)
+static void __fpstate_reset(struct fpstate *fpstate, u64 xfd);
+
+static void fpu_init_guest_permissions(struct fpu_guest *gfpu)
+{
+ struct fpu_state_perm *fpuperm;
+ u64 perm;
+
+ if (!IS_ENABLED(CONFIG_X86_64))
+ return;
+
+ spin_lock_irq(&current->sighand->siglock);
+ fpuperm = &current->group_leader->thread.fpu.guest_perm;
+ perm = fpuperm->__state_perm;
+
+ /* First fpstate allocation locks down permissions. */
+ WRITE_ONCE(fpuperm->__state_perm, perm | FPU_GUEST_PERM_LOCKED);
+
+ spin_unlock_irq(&current->sighand->siglock);
+
+ gfpu->perm = perm & ~FPU_GUEST_PERM_LOCKED;
+}
+
+bool fpu_alloc_guest_fpstate(struct fpu_guest *gfpu)
+{
+ struct fpstate *fpstate;
+ unsigned int size;
+
+ size = fpu_user_cfg.default_size + ALIGN(offsetof(struct fpstate, regs), 64);
+ fpstate = vzalloc(size);
+ if (!fpstate)
+ return false;
+
+ /* Leave xfd to 0 (the reset value defined by spec) */
+ __fpstate_reset(fpstate, 0);
+ fpstate_init_user(fpstate);
+ fpstate->is_valloc = true;
+ fpstate->is_guest = true;
+
+ gfpu->fpstate = fpstate;
+ gfpu->xfeatures = fpu_user_cfg.default_features;
+ gfpu->perm = fpu_user_cfg.default_features;
+
+ /*
+ * KVM sets the FP+SSE bits in the XSAVE header when copying FPU state
+ * to userspace, even when XSAVE is unsupported, so that restoring FPU
+ * state on a different CPU that does support XSAVE can cleanly load
+ * the incoming state using its natural XSAVE. In other words, KVM's
+ * uABI size may be larger than this host's default size. Conversely,
+ * the default size should never be larger than KVM's base uABI size;
+ * all features that can expand the uABI size must be opt-in.
+ */
+ gfpu->uabi_size = sizeof(struct kvm_xsave);
+ if (WARN_ON_ONCE(fpu_user_cfg.default_size > gfpu->uabi_size))
+ gfpu->uabi_size = fpu_user_cfg.default_size;
+
+ fpu_init_guest_permissions(gfpu);
+
+ return true;
+}
+EXPORT_SYMBOL_GPL(fpu_alloc_guest_fpstate);
+
+void fpu_free_guest_fpstate(struct fpu_guest *gfpu)
+{
+ struct fpstate *fps = gfpu->fpstate;
+
+ if (!fps)
+ return;
+
+ if (WARN_ON_ONCE(!fps->is_valloc || !fps->is_guest || fps->in_use))
+ return;
+
+ gfpu->fpstate = NULL;
+ vfree(fps);
+}
+EXPORT_SYMBOL_GPL(fpu_free_guest_fpstate);
+
+/*
+ * fpu_enable_guest_xfd_features - Check xfeatures against guest perm and enable
+ * @guest_fpu: Pointer to the guest FPU container
+ * @xfeatures: Features requested by guest CPUID
+ *
+ * Enable all dynamic xfeatures according to guest perm and requested CPUID.
+ *
+ * Return: 0 on success, error code otherwise
+ */
+int fpu_enable_guest_xfd_features(struct fpu_guest *guest_fpu, u64 xfeatures)
+{
+ lockdep_assert_preemption_enabled();
+
+ /* Nothing to do if all requested features are already enabled. */
+ xfeatures &= ~guest_fpu->xfeatures;
+ if (!xfeatures)
+ return 0;
+
+ return __xfd_enable_feature(xfeatures, guest_fpu);
+}
+EXPORT_SYMBOL_GPL(fpu_enable_guest_xfd_features);
+
+#ifdef CONFIG_X86_64
+void fpu_update_guest_xfd(struct fpu_guest *guest_fpu, u64 xfd)
+{
+ fpregs_lock();
+ guest_fpu->fpstate->xfd = xfd;
+ if (guest_fpu->fpstate->in_use)
+ xfd_update_state(guest_fpu->fpstate);
+ fpregs_unlock();
+}
+EXPORT_SYMBOL_GPL(fpu_update_guest_xfd);
+
+/**
+ * fpu_sync_guest_vmexit_xfd_state - Synchronize XFD MSR and software state
+ *
+ * Must be invoked from KVM after a VMEXIT before enabling interrupts when
+ * XFD write emulation is disabled. This is required because the guest can
+ * freely modify XFD and the state at VMEXIT is not guaranteed to be the
+ * same as the state on VMENTER. So software state has to be udpated before
+ * any operation which depends on it can take place.
+ *
+ * Note: It can be invoked unconditionally even when write emulation is
+ * enabled for the price of a then pointless MSR read.
+ */
+void fpu_sync_guest_vmexit_xfd_state(void)
+{
+ struct fpstate *fps = current->thread.fpu.fpstate;
+
+ lockdep_assert_irqs_disabled();
+ if (fpu_state_size_dynamic()) {
+ rdmsrl(MSR_IA32_XFD, fps->xfd);
+ __this_cpu_write(xfd_state, fps->xfd);
+ }
+}
+EXPORT_SYMBOL_GPL(fpu_sync_guest_vmexit_xfd_state);
+#endif /* CONFIG_X86_64 */
+
+int fpu_swap_kvm_fpstate(struct fpu_guest *guest_fpu, bool enter_guest)
+{
+ struct fpstate *guest_fps = guest_fpu->fpstate;
+ struct fpu *fpu = &current->thread.fpu;
+ struct fpstate *cur_fps = fpu->fpstate;
+
+ fpregs_lock();
+ if (!cur_fps->is_confidential && !test_thread_flag(TIF_NEED_FPU_LOAD))
+ save_fpregs_to_fpstate(fpu);
+
+ /* Swap fpstate */
+ if (enter_guest) {
+ fpu->__task_fpstate = cur_fps;
+ fpu->fpstate = guest_fps;
+ guest_fps->in_use = true;
+ } else {
+ guest_fps->in_use = false;
+ fpu->fpstate = fpu->__task_fpstate;
+ fpu->__task_fpstate = NULL;
+ }
+
+ cur_fps = fpu->fpstate;
+
+ if (!cur_fps->is_confidential) {
+ /* Includes XFD update */
+ restore_fpregs_from_fpstate(cur_fps, XFEATURE_MASK_FPSTATE);
+ } else {
+ /*
+ * XSTATE is restored by firmware from encrypted
+ * memory. Make sure XFD state is correct while
+ * running with guest fpstate
+ */
+ xfd_update_state(cur_fps);
+ }
+
+ fpregs_mark_activate();
+ fpregs_unlock();
+ return 0;
+}
+EXPORT_SYMBOL_GPL(fpu_swap_kvm_fpstate);
+
+void fpu_copy_guest_fpstate_to_uabi(struct fpu_guest *gfpu, void *buf,
+ unsigned int size, u32 pkru)
+{
+ struct fpstate *kstate = gfpu->fpstate;
+ union fpregs_state *ustate = buf;
+ struct membuf mb = { .p = buf, .left = size };
+
+ if (cpu_feature_enabled(X86_FEATURE_XSAVE)) {
+ __copy_xstate_to_uabi_buf(mb, kstate, pkru, XSTATE_COPY_XSAVE);
+ } else {
+ memcpy(&ustate->fxsave, &kstate->regs.fxsave,
+ sizeof(ustate->fxsave));
+ /* Make it restorable on a XSAVE enabled host */
+ ustate->xsave.header.xfeatures = XFEATURE_MASK_FPSSE;
+ }
+}
+EXPORT_SYMBOL_GPL(fpu_copy_guest_fpstate_to_uabi);
+
+int fpu_copy_uabi_to_guest_fpstate(struct fpu_guest *gfpu, const void *buf,
+ u64 xcr0, u32 *vpkru)
+{
+ struct fpstate *kstate = gfpu->fpstate;
+ const union fpregs_state *ustate = buf;
+
+ if (!cpu_feature_enabled(X86_FEATURE_XSAVE)) {
+ if (ustate->xsave.header.xfeatures & ~XFEATURE_MASK_FPSSE)
+ return -EINVAL;
+ if (ustate->fxsave.mxcsr & ~mxcsr_feature_mask)
+ return -EINVAL;
+ memcpy(&kstate->regs.fxsave, &ustate->fxsave, sizeof(ustate->fxsave));
+ return 0;
+ }
+
+ if (ustate->xsave.header.xfeatures & ~xcr0)
+ return -EINVAL;
+
+ /*
+ * Nullify @vpkru to preserve its current value if PKRU's bit isn't set
+ * in the header. KVM's odd ABI is to leave PKRU untouched in this
+ * case (all other components are eventually re-initialized).
+ */
+ if (!(ustate->xsave.header.xfeatures & XFEATURE_MASK_PKRU))
+ vpkru = NULL;
+
+ return copy_uabi_from_kernel_to_xstate(kstate, ustate, vpkru);
+}
+EXPORT_SYMBOL_GPL(fpu_copy_uabi_to_guest_fpstate);
+#endif /* CONFIG_KVM */
+
+void kernel_fpu_begin_mask(unsigned int kfpu_mask)
+{
+ preempt_disable();
+
+ WARN_ON_FPU(!irq_fpu_usable());
+ WARN_ON_FPU(this_cpu_read(in_kernel_fpu));
+
+ this_cpu_write(in_kernel_fpu, true);
+
+ if (!(current->flags & (PF_KTHREAD | PF_IO_WORKER)) &&
+ !test_thread_flag(TIF_NEED_FPU_LOAD)) {
+ set_thread_flag(TIF_NEED_FPU_LOAD);
+ save_fpregs_to_fpstate(&current->thread.fpu);
+ }
+ __cpu_invalidate_fpregs_state();
+
+ /* Put sane initial values into the control registers. */
+ if (likely(kfpu_mask & KFPU_MXCSR) && boot_cpu_has(X86_FEATURE_XMM))
+ ldmxcsr(MXCSR_DEFAULT);
+
+ if (unlikely(kfpu_mask & KFPU_387) && boot_cpu_has(X86_FEATURE_FPU))
+ asm volatile ("fninit");
+}
+EXPORT_SYMBOL_GPL(kernel_fpu_begin_mask);
+
+void kernel_fpu_end(void)
+{
+ WARN_ON_FPU(!this_cpu_read(in_kernel_fpu));
+
+ this_cpu_write(in_kernel_fpu, false);
+ preempt_enable();
+}
+EXPORT_SYMBOL_GPL(kernel_fpu_end);
+
+/*
+ * Sync the FPU register state to current's memory register state when the
+ * current task owns the FPU. The hardware register state is preserved.
+ */
+void fpu_sync_fpstate(struct fpu *fpu)
+{
+ WARN_ON_FPU(fpu != &current->thread.fpu);
+
+ fpregs_lock();
+ trace_x86_fpu_before_save(fpu);
+
+ if (!test_thread_flag(TIF_NEED_FPU_LOAD))
+ save_fpregs_to_fpstate(fpu);
+
+ trace_x86_fpu_after_save(fpu);
+ fpregs_unlock();
+}
+
+static inline unsigned int init_fpstate_copy_size(void)
+{
+ if (!use_xsave())
+ return fpu_kernel_cfg.default_size;
+
+ /* XSAVE(S) just needs the legacy and the xstate header part */
+ return sizeof(init_fpstate.regs.xsave);
+}
+
+static inline void fpstate_init_fxstate(struct fpstate *fpstate)
+{
+ fpstate->regs.fxsave.cwd = 0x37f;
+ fpstate->regs.fxsave.mxcsr = MXCSR_DEFAULT;
+}
+
+/*
+ * Legacy x87 fpstate state init:
+ */
+static inline void fpstate_init_fstate(struct fpstate *fpstate)
+{
+ fpstate->regs.fsave.cwd = 0xffff037fu;
+ fpstate->regs.fsave.swd = 0xffff0000u;
+ fpstate->regs.fsave.twd = 0xffffffffu;
+ fpstate->regs.fsave.fos = 0xffff0000u;
+}
+
+/*
+ * Used in two places:
+ * 1) Early boot to setup init_fpstate for non XSAVE systems
+ * 2) fpu_init_fpstate_user() which is invoked from KVM
+ */
+void fpstate_init_user(struct fpstate *fpstate)
+{
+ if (!cpu_feature_enabled(X86_FEATURE_FPU)) {
+ fpstate_init_soft(&fpstate->regs.soft);
+ return;
+ }
+
+ xstate_init_xcomp_bv(&fpstate->regs.xsave, fpstate->xfeatures);
+
+ if (cpu_feature_enabled(X86_FEATURE_FXSR))
+ fpstate_init_fxstate(fpstate);
+ else
+ fpstate_init_fstate(fpstate);
+}
+
+static void __fpstate_reset(struct fpstate *fpstate, u64 xfd)
+{
+ /* Initialize sizes and feature masks */
+ fpstate->size = fpu_kernel_cfg.default_size;
+ fpstate->user_size = fpu_user_cfg.default_size;
+ fpstate->xfeatures = fpu_kernel_cfg.default_features;
+ fpstate->user_xfeatures = fpu_user_cfg.default_features;
+ fpstate->xfd = xfd;
+}
+
+void fpstate_reset(struct fpu *fpu)
+{
+ /* Set the fpstate pointer to the default fpstate */
+ fpu->fpstate = &fpu->__fpstate;
+ __fpstate_reset(fpu->fpstate, init_fpstate.xfd);
+
+ /* Initialize the permission related info in fpu */
+ fpu->perm.__state_perm = fpu_kernel_cfg.default_features;
+ fpu->perm.__state_size = fpu_kernel_cfg.default_size;
+ fpu->perm.__user_state_size = fpu_user_cfg.default_size;
+ /* Same defaults for guests */
+ fpu->guest_perm = fpu->perm;
+}
+
+static inline void fpu_inherit_perms(struct fpu *dst_fpu)
+{
+ if (fpu_state_size_dynamic()) {
+ struct fpu *src_fpu = &current->group_leader->thread.fpu;
+
+ spin_lock_irq(&current->sighand->siglock);
+ /* Fork also inherits the permissions of the parent */
+ dst_fpu->perm = src_fpu->perm;
+ dst_fpu->guest_perm = src_fpu->guest_perm;
+ spin_unlock_irq(&current->sighand->siglock);
+ }
+}
+
+/* Clone current's FPU state on fork */
+int fpu_clone(struct task_struct *dst, unsigned long clone_flags, bool minimal)
+{
+ struct fpu *src_fpu = &current->thread.fpu;
+ struct fpu *dst_fpu = &dst->thread.fpu;
+
+ /* The new task's FPU state cannot be valid in the hardware. */
+ dst_fpu->last_cpu = -1;
+
+ fpstate_reset(dst_fpu);
+
+ if (!cpu_feature_enabled(X86_FEATURE_FPU))
+ return 0;
+
+ /*
+ * Enforce reload for user space tasks and prevent kernel threads
+ * from trying to save the FPU registers on context switch.
+ */
+ set_tsk_thread_flag(dst, TIF_NEED_FPU_LOAD);
+
+ /*
+ * No FPU state inheritance for kernel threads and IO
+ * worker threads.
+ */
+ if (minimal) {
+ /* Clear out the minimal state */
+ memcpy(&dst_fpu->fpstate->regs, &init_fpstate.regs,
+ init_fpstate_copy_size());
+ return 0;
+ }
+
+ /*
+ * If a new feature is added, ensure all dynamic features are
+ * caller-saved from here!
+ */
+ BUILD_BUG_ON(XFEATURE_MASK_USER_DYNAMIC != XFEATURE_MASK_XTILE_DATA);
+
+ /*
+ * Save the default portion of the current FPU state into the
+ * clone. Assume all dynamic features to be defined as caller-
+ * saved, which enables skipping both the expansion of fpstate
+ * and the copying of any dynamic state.
+ *
+ * Do not use memcpy() when TIF_NEED_FPU_LOAD is set because
+ * copying is not valid when current uses non-default states.
+ */
+ fpregs_lock();
+ if (test_thread_flag(TIF_NEED_FPU_LOAD))
+ fpregs_restore_userregs();
+ save_fpregs_to_fpstate(dst_fpu);
+ fpregs_unlock();
+ if (!(clone_flags & CLONE_THREAD))
+ fpu_inherit_perms(dst_fpu);
+
+ /*
+ * Children never inherit PASID state.
+ * Force it to have its init value:
+ */
+ if (use_xsave())
+ dst_fpu->fpstate->regs.xsave.header.xfeatures &= ~XFEATURE_MASK_PASID;
+
+ trace_x86_fpu_copy_src(src_fpu);
+ trace_x86_fpu_copy_dst(dst_fpu);
+
+ return 0;
+}
+
+/*
+ * Whitelist the FPU register state embedded into task_struct for hardened
+ * usercopy.
+ */
+void fpu_thread_struct_whitelist(unsigned long *offset, unsigned long *size)
+{
+ *offset = offsetof(struct thread_struct, fpu.__fpstate.regs);
+ *size = fpu_kernel_cfg.default_size;
+}
+
+/*
+ * Drops current FPU state: deactivates the fpregs and
+ * the fpstate. NOTE: it still leaves previous contents
+ * in the fpregs in the eager-FPU case.
+ *
+ * This function can be used in cases where we know that
+ * a state-restore is coming: either an explicit one,
+ * or a reschedule.
+ */
+void fpu__drop(struct fpu *fpu)
+{
+ preempt_disable();
+
+ if (fpu == &current->thread.fpu) {
+ /* Ignore delayed exceptions from user space */
+ asm volatile("1: fwait\n"
+ "2:\n"
+ _ASM_EXTABLE(1b, 2b));
+ fpregs_deactivate(fpu);
+ }
+
+ trace_x86_fpu_dropped(fpu);
+
+ preempt_enable();
+}
+
+/*
+ * Clear FPU registers by setting them up from the init fpstate.
+ * Caller must do fpregs_[un]lock() around it.
+ */
+static inline void restore_fpregs_from_init_fpstate(u64 features_mask)
+{
+ if (use_xsave())
+ os_xrstor(&init_fpstate, features_mask);
+ else if (use_fxsr())
+ fxrstor(&init_fpstate.regs.fxsave);
+ else
+ frstor(&init_fpstate.regs.fsave);
+
+ pkru_write_default();
+}
+
+/*
+ * Reset current->fpu memory state to the init values.
+ */
+static void fpu_reset_fpregs(void)
+{
+ struct fpu *fpu = &current->thread.fpu;
+
+ fpregs_lock();
+ fpu__drop(fpu);
+ /*
+ * This does not change the actual hardware registers. It just
+ * resets the memory image and sets TIF_NEED_FPU_LOAD so a
+ * subsequent return to usermode will reload the registers from the
+ * task's memory image.
+ *
+ * Do not use fpstate_init() here. Just copy init_fpstate which has
+ * the correct content already except for PKRU.
+ *
+ * PKRU handling does not rely on the xstate when restoring for
+ * user space as PKRU is eagerly written in switch_to() and
+ * flush_thread().
+ */
+ memcpy(&fpu->fpstate->regs, &init_fpstate.regs, init_fpstate_copy_size());
+ set_thread_flag(TIF_NEED_FPU_LOAD);
+ fpregs_unlock();
+}
+
+/*
+ * Reset current's user FPU states to the init states. current's
+ * supervisor states, if any, are not modified by this function. The
+ * caller guarantees that the XSTATE header in memory is intact.
+ */
+void fpu__clear_user_states(struct fpu *fpu)
+{
+ WARN_ON_FPU(fpu != &current->thread.fpu);
+
+ fpregs_lock();
+ if (!cpu_feature_enabled(X86_FEATURE_FPU)) {
+ fpu_reset_fpregs();
+ fpregs_unlock();
+ return;
+ }
+
+ /*
+ * Ensure that current's supervisor states are loaded into their
+ * corresponding registers.
+ */
+ if (xfeatures_mask_supervisor() &&
+ !fpregs_state_valid(fpu, smp_processor_id()))
+ os_xrstor_supervisor(fpu->fpstate);
+
+ /* Reset user states in registers. */
+ restore_fpregs_from_init_fpstate(XFEATURE_MASK_USER_RESTORE);
+
+ /*
+ * Now all FPU registers have their desired values. Inform the FPU
+ * state machine that current's FPU registers are in the hardware
+ * registers. The memory image does not need to be updated because
+ * any operation relying on it has to save the registers first when
+ * current's FPU is marked active.
+ */
+ fpregs_mark_activate();
+ fpregs_unlock();
+}
+
+void fpu_flush_thread(void)
+{
+ fpstate_reset(&current->thread.fpu);
+ fpu_reset_fpregs();
+}
+/*
+ * Load FPU context before returning to userspace.
+ */
+void switch_fpu_return(void)
+{
+ if (!static_cpu_has(X86_FEATURE_FPU))
+ return;
+
+ fpregs_restore_userregs();
+}
+EXPORT_SYMBOL_GPL(switch_fpu_return);
+
+#ifdef CONFIG_X86_DEBUG_FPU
+/*
+ * If current FPU state according to its tracking (loaded FPU context on this
+ * CPU) is not valid then we must have TIF_NEED_FPU_LOAD set so the context is
+ * loaded on return to userland.
+ */
+void fpregs_assert_state_consistent(void)
+{
+ struct fpu *fpu = &current->thread.fpu;
+
+ if (test_thread_flag(TIF_NEED_FPU_LOAD))
+ return;
+
+ WARN_ON_FPU(!fpregs_state_valid(fpu, smp_processor_id()));
+}
+EXPORT_SYMBOL_GPL(fpregs_assert_state_consistent);
+#endif
+
+void fpregs_mark_activate(void)
+{
+ struct fpu *fpu = &current->thread.fpu;
+
+ fpregs_activate(fpu);
+ fpu->last_cpu = smp_processor_id();
+ clear_thread_flag(TIF_NEED_FPU_LOAD);
+}
+
+/*
+ * x87 math exception handling:
+ */
+
+int fpu__exception_code(struct fpu *fpu, int trap_nr)
+{
+ int err;
+
+ if (trap_nr == X86_TRAP_MF) {
+ unsigned short cwd, swd;
+ /*
+ * (~cwd & swd) will mask out exceptions that are not set to unmasked
+ * status. 0x3f is the exception bits in these regs, 0x200 is the
+ * C1 reg you need in case of a stack fault, 0x040 is the stack
+ * fault bit. We should only be taking one exception at a time,
+ * so if this combination doesn't produce any single exception,
+ * then we have a bad program that isn't synchronizing its FPU usage
+ * and it will suffer the consequences since we won't be able to
+ * fully reproduce the context of the exception.
+ */
+ if (boot_cpu_has(X86_FEATURE_FXSR)) {
+ cwd = fpu->fpstate->regs.fxsave.cwd;
+ swd = fpu->fpstate->regs.fxsave.swd;
+ } else {
+ cwd = (unsigned short)fpu->fpstate->regs.fsave.cwd;
+ swd = (unsigned short)fpu->fpstate->regs.fsave.swd;
+ }
+
+ err = swd & ~cwd;
+ } else {
+ /*
+ * The SIMD FPU exceptions are handled a little differently, as there
+ * is only a single status/control register. Thus, to determine which
+ * unmasked exception was caught we must mask the exception mask bits
+ * at 0x1f80, and then use these to mask the exception bits at 0x3f.
+ */
+ unsigned short mxcsr = MXCSR_DEFAULT;
+
+ if (boot_cpu_has(X86_FEATURE_XMM))
+ mxcsr = fpu->fpstate->regs.fxsave.mxcsr;
+
+ err = ~(mxcsr >> 7) & mxcsr;
+ }
+
+ if (err & 0x001) { /* Invalid op */
+ /*
+ * swd & 0x240 == 0x040: Stack Underflow
+ * swd & 0x240 == 0x240: Stack Overflow
+ * User must clear the SF bit (0x40) if set
+ */
+ return FPE_FLTINV;
+ } else if (err & 0x004) { /* Divide by Zero */
+ return FPE_FLTDIV;
+ } else if (err & 0x008) { /* Overflow */
+ return FPE_FLTOVF;
+ } else if (err & 0x012) { /* Denormal, Underflow */
+ return FPE_FLTUND;
+ } else if (err & 0x020) { /* Precision */
+ return FPE_FLTRES;
+ }
+
+ /*
+ * If we're using IRQ 13, or supposedly even some trap
+ * X86_TRAP_MF implementations, it's possible
+ * we get a spurious trap, which is not an error.
+ */
+ return 0;
+}
+
+/*
+ * Initialize register state that may prevent from entering low-power idle.
+ * This function will be invoked from the cpuidle driver only when needed.
+ */
+noinstr void fpu_idle_fpregs(void)
+{
+ /* Note: AMX_TILE being enabled implies XGETBV1 support */
+ if (cpu_feature_enabled(X86_FEATURE_AMX_TILE) &&
+ (xfeatures_in_use() & XFEATURE_MASK_XTILE)) {
+ tile_release();
+ __this_cpu_write(fpu_fpregs_owner_ctx, NULL);
+ }
+}