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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/signal.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 'arch/x86/kernel/fpu/signal.c')
-rw-r--r--arch/x86/kernel/fpu/signal.c542
1 files changed, 542 insertions, 0 deletions
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
new file mode 100644
index 000000000..558076dbd
--- /dev/null
+++ b/arch/x86/kernel/fpu/signal.c
@@ -0,0 +1,542 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * FPU signal frame handling routines.
+ */
+
+#include <linux/compat.h>
+#include <linux/cpu.h>
+#include <linux/pagemap.h>
+
+#include <asm/fpu/signal.h>
+#include <asm/fpu/regset.h>
+#include <asm/fpu/xstate.h>
+
+#include <asm/sigframe.h>
+#include <asm/trapnr.h>
+#include <asm/trace/fpu.h>
+
+#include "context.h"
+#include "internal.h"
+#include "legacy.h"
+#include "xstate.h"
+
+/*
+ * Check for the presence of extended state information in the
+ * user fpstate pointer in the sigcontext.
+ */
+static inline bool check_xstate_in_sigframe(struct fxregs_state __user *fxbuf,
+ struct _fpx_sw_bytes *fx_sw)
+{
+ int min_xstate_size = sizeof(struct fxregs_state) +
+ sizeof(struct xstate_header);
+ void __user *fpstate = fxbuf;
+ unsigned int magic2;
+
+ if (__copy_from_user(fx_sw, &fxbuf->sw_reserved[0], sizeof(*fx_sw)))
+ return false;
+
+ /* Check for the first magic field and other error scenarios. */
+ if (fx_sw->magic1 != FP_XSTATE_MAGIC1 ||
+ fx_sw->xstate_size < min_xstate_size ||
+ fx_sw->xstate_size > current->thread.fpu.fpstate->user_size ||
+ fx_sw->xstate_size > fx_sw->extended_size)
+ goto setfx;
+
+ /*
+ * Check for the presence of second magic word at the end of memory
+ * layout. This detects the case where the user just copied the legacy
+ * fpstate layout with out copying the extended state information
+ * in the memory layout.
+ */
+ if (__get_user(magic2, (__u32 __user *)(fpstate + fx_sw->xstate_size)))
+ return false;
+
+ if (likely(magic2 == FP_XSTATE_MAGIC2))
+ return true;
+setfx:
+ trace_x86_fpu_xstate_check_failed(&current->thread.fpu);
+
+ /* Set the parameters for fx only state */
+ fx_sw->magic1 = 0;
+ fx_sw->xstate_size = sizeof(struct fxregs_state);
+ fx_sw->xfeatures = XFEATURE_MASK_FPSSE;
+ return true;
+}
+
+/*
+ * Signal frame handlers.
+ */
+static inline bool save_fsave_header(struct task_struct *tsk, void __user *buf)
+{
+ if (use_fxsr()) {
+ struct xregs_state *xsave = &tsk->thread.fpu.fpstate->regs.xsave;
+ struct user_i387_ia32_struct env;
+ struct _fpstate_32 __user *fp = buf;
+
+ fpregs_lock();
+ if (!test_thread_flag(TIF_NEED_FPU_LOAD))
+ fxsave(&tsk->thread.fpu.fpstate->regs.fxsave);
+ fpregs_unlock();
+
+ convert_from_fxsr(&env, tsk);
+
+ if (__copy_to_user(buf, &env, sizeof(env)) ||
+ __put_user(xsave->i387.swd, &fp->status) ||
+ __put_user(X86_FXSR_MAGIC, &fp->magic))
+ return false;
+ } else {
+ struct fregs_state __user *fp = buf;
+ u32 swd;
+
+ if (__get_user(swd, &fp->swd) || __put_user(swd, &fp->status))
+ return false;
+ }
+
+ return true;
+}
+
+/*
+ * Prepare the SW reserved portion of the fxsave memory layout, indicating
+ * the presence of the extended state information in the memory layout
+ * pointed to by the fpstate pointer in the sigcontext.
+ * This is saved when ever the FP and extended state context is
+ * saved on the user stack during the signal handler delivery to the user.
+ */
+static inline void save_sw_bytes(struct _fpx_sw_bytes *sw_bytes, bool ia32_frame,
+ struct fpstate *fpstate)
+{
+ sw_bytes->magic1 = FP_XSTATE_MAGIC1;
+ sw_bytes->extended_size = fpstate->user_size + FP_XSTATE_MAGIC2_SIZE;
+ sw_bytes->xfeatures = fpstate->user_xfeatures;
+ sw_bytes->xstate_size = fpstate->user_size;
+
+ if (ia32_frame)
+ sw_bytes->extended_size += sizeof(struct fregs_state);
+}
+
+static inline bool save_xstate_epilog(void __user *buf, int ia32_frame,
+ struct fpstate *fpstate)
+{
+ struct xregs_state __user *x = buf;
+ struct _fpx_sw_bytes sw_bytes = {};
+ u32 xfeatures;
+ int err;
+
+ /* Setup the bytes not touched by the [f]xsave and reserved for SW. */
+ save_sw_bytes(&sw_bytes, ia32_frame, fpstate);
+ err = __copy_to_user(&x->i387.sw_reserved, &sw_bytes, sizeof(sw_bytes));
+
+ if (!use_xsave())
+ return !err;
+
+ err |= __put_user(FP_XSTATE_MAGIC2,
+ (__u32 __user *)(buf + fpstate->user_size));
+
+ /*
+ * Read the xfeatures which we copied (directly from the cpu or
+ * from the state in task struct) to the user buffers.
+ */
+ err |= __get_user(xfeatures, (__u32 __user *)&x->header.xfeatures);
+
+ /*
+ * For legacy compatible, we always set FP/SSE bits in the bit
+ * vector while saving the state to the user context. This will
+ * enable us capturing any changes(during sigreturn) to
+ * the FP/SSE bits by the legacy applications which don't touch
+ * xfeatures in the xsave header.
+ *
+ * xsave aware apps can change the xfeatures in the xsave
+ * header as well as change any contents in the memory layout.
+ * xrestore as part of sigreturn will capture all the changes.
+ */
+ xfeatures |= XFEATURE_MASK_FPSSE;
+
+ err |= __put_user(xfeatures, (__u32 __user *)&x->header.xfeatures);
+
+ return !err;
+}
+
+static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf)
+{
+ if (use_xsave())
+ return xsave_to_user_sigframe(buf);
+ if (use_fxsr())
+ return fxsave_to_user_sigframe((struct fxregs_state __user *) buf);
+ else
+ return fnsave_to_user_sigframe((struct fregs_state __user *) buf);
+}
+
+/*
+ * Save the fpu, extended register state to the user signal frame.
+ *
+ * 'buf_fx' is the 64-byte aligned pointer at which the [f|fx|x]save
+ * state is copied.
+ * 'buf' points to the 'buf_fx' or to the fsave header followed by 'buf_fx'.
+ *
+ * buf == buf_fx for 64-bit frames and 32-bit fsave frame.
+ * buf != buf_fx for 32-bit frames with fxstate.
+ *
+ * Save it directly to the user frame with disabled page fault handler. If
+ * that faults, try to clear the frame which handles the page fault.
+ *
+ * If this is a 32-bit frame with fxstate, put a fsave header before
+ * the aligned state at 'buf_fx'.
+ *
+ * For [f]xsave state, update the SW reserved fields in the [f]xsave frame
+ * indicating the absence/presence of the extended state to the user.
+ */
+bool copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
+{
+ struct task_struct *tsk = current;
+ struct fpstate *fpstate = tsk->thread.fpu.fpstate;
+ bool ia32_fxstate = (buf != buf_fx);
+ int ret;
+
+ ia32_fxstate &= (IS_ENABLED(CONFIG_X86_32) ||
+ IS_ENABLED(CONFIG_IA32_EMULATION));
+
+ if (!static_cpu_has(X86_FEATURE_FPU)) {
+ struct user_i387_ia32_struct fp;
+
+ fpregs_soft_get(current, NULL, (struct membuf){.p = &fp,
+ .left = sizeof(fp)});
+ return !copy_to_user(buf, &fp, sizeof(fp));
+ }
+
+ if (!access_ok(buf, size))
+ return false;
+
+ if (use_xsave()) {
+ struct xregs_state __user *xbuf = buf_fx;
+
+ /*
+ * Clear the xsave header first, so that reserved fields are
+ * initialized to zero.
+ */
+ if (__clear_user(&xbuf->header, sizeof(xbuf->header)))
+ return false;
+ }
+retry:
+ /*
+ * Load the FPU registers if they are not valid for the current task.
+ * With a valid FPU state we can attempt to save the state directly to
+ * userland's stack frame which will likely succeed. If it does not,
+ * resolve the fault in the user memory and try again.
+ */
+ fpregs_lock();
+ if (test_thread_flag(TIF_NEED_FPU_LOAD))
+ fpregs_restore_userregs();
+
+ pagefault_disable();
+ ret = copy_fpregs_to_sigframe(buf_fx);
+ pagefault_enable();
+ fpregs_unlock();
+
+ if (ret) {
+ if (!__clear_user(buf_fx, fpstate->user_size))
+ goto retry;
+ return false;
+ }
+
+ /* Save the fsave header for the 32-bit frames. */
+ if ((ia32_fxstate || !use_fxsr()) && !save_fsave_header(tsk, buf))
+ return false;
+
+ if (use_fxsr() && !save_xstate_epilog(buf_fx, ia32_fxstate, fpstate))
+ return false;
+
+ return true;
+}
+
+static int __restore_fpregs_from_user(void __user *buf, u64 ufeatures,
+ u64 xrestore, bool fx_only)
+{
+ if (use_xsave()) {
+ u64 init_bv = ufeatures & ~xrestore;
+ int ret;
+
+ if (likely(!fx_only))
+ ret = xrstor_from_user_sigframe(buf, xrestore);
+ else
+ ret = fxrstor_from_user_sigframe(buf);
+
+ if (!ret && unlikely(init_bv))
+ os_xrstor(&init_fpstate, init_bv);
+ return ret;
+ } else if (use_fxsr()) {
+ return fxrstor_from_user_sigframe(buf);
+ } else {
+ return frstor_from_user_sigframe(buf);
+ }
+}
+
+/*
+ * Attempt to restore the FPU registers directly from user memory.
+ * Pagefaults are handled and any errors returned are fatal.
+ */
+static bool restore_fpregs_from_user(void __user *buf, u64 xrestore,
+ bool fx_only, unsigned int size)
+{
+ struct fpu *fpu = &current->thread.fpu;
+ int ret;
+
+retry:
+ fpregs_lock();
+ /* Ensure that XFD is up to date */
+ xfd_update_state(fpu->fpstate);
+ pagefault_disable();
+ ret = __restore_fpregs_from_user(buf, fpu->fpstate->user_xfeatures,
+ xrestore, fx_only);
+ pagefault_enable();
+
+ if (unlikely(ret)) {
+ /*
+ * The above did an FPU restore operation, restricted to
+ * the user portion of the registers, and failed, but the
+ * microcode might have modified the FPU registers
+ * nevertheless.
+ *
+ * If the FPU registers do not belong to current, then
+ * invalidate the FPU register state otherwise the task
+ * might preempt current and return to user space with
+ * corrupted FPU registers.
+ */
+ if (test_thread_flag(TIF_NEED_FPU_LOAD))
+ __cpu_invalidate_fpregs_state();
+ fpregs_unlock();
+
+ /* Try to handle #PF, but anything else is fatal. */
+ if (ret != X86_TRAP_PF)
+ return false;
+
+ if (!fault_in_readable(buf, size))
+ goto retry;
+ return false;
+ }
+
+ /*
+ * Restore supervisor states: previous context switch etc has done
+ * XSAVES and saved the supervisor states in the kernel buffer from
+ * which they can be restored now.
+ *
+ * It would be optimal to handle this with a single XRSTORS, but
+ * this does not work because the rest of the FPU registers have
+ * been restored from a user buffer directly.
+ */
+ if (test_thread_flag(TIF_NEED_FPU_LOAD) && xfeatures_mask_supervisor())
+ os_xrstor_supervisor(fpu->fpstate);
+
+ fpregs_mark_activate();
+ fpregs_unlock();
+ return true;
+}
+
+static bool __fpu_restore_sig(void __user *buf, void __user *buf_fx,
+ bool ia32_fxstate)
+{
+ struct task_struct *tsk = current;
+ struct fpu *fpu = &tsk->thread.fpu;
+ struct user_i387_ia32_struct env;
+ bool success, fx_only = false;
+ union fpregs_state *fpregs;
+ unsigned int state_size;
+ u64 user_xfeatures = 0;
+
+ if (use_xsave()) {
+ struct _fpx_sw_bytes fx_sw_user;
+
+ if (!check_xstate_in_sigframe(buf_fx, &fx_sw_user))
+ return false;
+
+ fx_only = !fx_sw_user.magic1;
+ state_size = fx_sw_user.xstate_size;
+ user_xfeatures = fx_sw_user.xfeatures;
+ } else {
+ user_xfeatures = XFEATURE_MASK_FPSSE;
+ state_size = fpu->fpstate->user_size;
+ }
+
+ if (likely(!ia32_fxstate)) {
+ /* Restore the FPU registers directly from user memory. */
+ return restore_fpregs_from_user(buf_fx, user_xfeatures, fx_only,
+ state_size);
+ }
+
+ /*
+ * Copy the legacy state because the FP portion of the FX frame has
+ * to be ignored for histerical raisins. The legacy state is folded
+ * in once the larger state has been copied.
+ */
+ if (__copy_from_user(&env, buf, sizeof(env)))
+ return false;
+
+ /*
+ * By setting TIF_NEED_FPU_LOAD it is ensured that our xstate is
+ * not modified on context switch and that the xstate is considered
+ * to be loaded again on return to userland (overriding last_cpu avoids
+ * the optimisation).
+ */
+ fpregs_lock();
+ if (!test_thread_flag(TIF_NEED_FPU_LOAD)) {
+ /*
+ * If supervisor states are available then save the
+ * hardware state in current's fpstate so that the
+ * supervisor state is preserved. Save the full state for
+ * simplicity. There is no point in optimizing this by only
+ * saving the supervisor states and then shuffle them to
+ * the right place in memory. It's ia32 mode. Shrug.
+ */
+ if (xfeatures_mask_supervisor())
+ os_xsave(fpu->fpstate);
+ set_thread_flag(TIF_NEED_FPU_LOAD);
+ }
+ __fpu_invalidate_fpregs_state(fpu);
+ __cpu_invalidate_fpregs_state();
+ fpregs_unlock();
+
+ fpregs = &fpu->fpstate->regs;
+ if (use_xsave() && !fx_only) {
+ if (copy_sigframe_from_user_to_xstate(tsk, buf_fx))
+ return false;
+ } else {
+ if (__copy_from_user(&fpregs->fxsave, buf_fx,
+ sizeof(fpregs->fxsave)))
+ return false;
+
+ if (IS_ENABLED(CONFIG_X86_64)) {
+ /* Reject invalid MXCSR values. */
+ if (fpregs->fxsave.mxcsr & ~mxcsr_feature_mask)
+ return false;
+ } else {
+ /* Mask invalid bits out for historical reasons (broken hardware). */
+ fpregs->fxsave.mxcsr &= mxcsr_feature_mask;
+ }
+
+ /* Enforce XFEATURE_MASK_FPSSE when XSAVE is enabled */
+ if (use_xsave())
+ fpregs->xsave.header.xfeatures |= XFEATURE_MASK_FPSSE;
+ }
+
+ /* Fold the legacy FP storage */
+ convert_to_fxsr(&fpregs->fxsave, &env);
+
+ fpregs_lock();
+ if (use_xsave()) {
+ /*
+ * Remove all UABI feature bits not set in user_xfeatures
+ * from the memory xstate header which makes the full
+ * restore below bring them into init state. This works for
+ * fx_only mode as well because that has only FP and SSE
+ * set in user_xfeatures.
+ *
+ * Preserve supervisor states!
+ */
+ u64 mask = user_xfeatures | xfeatures_mask_supervisor();
+
+ fpregs->xsave.header.xfeatures &= mask;
+ success = !os_xrstor_safe(fpu->fpstate,
+ fpu_kernel_cfg.max_features);
+ } else {
+ success = !fxrstor_safe(&fpregs->fxsave);
+ }
+
+ if (likely(success))
+ fpregs_mark_activate();
+
+ fpregs_unlock();
+ return success;
+}
+
+static inline unsigned int xstate_sigframe_size(struct fpstate *fpstate)
+{
+ unsigned int size = fpstate->user_size;
+
+ return use_xsave() ? size + FP_XSTATE_MAGIC2_SIZE : size;
+}
+
+/*
+ * Restore FPU state from a sigframe:
+ */
+bool fpu__restore_sig(void __user *buf, int ia32_frame)
+{
+ struct fpu *fpu = &current->thread.fpu;
+ void __user *buf_fx = buf;
+ bool ia32_fxstate = false;
+ bool success = false;
+ unsigned int size;
+
+ if (unlikely(!buf)) {
+ fpu__clear_user_states(fpu);
+ return true;
+ }
+
+ size = xstate_sigframe_size(fpu->fpstate);
+
+ ia32_frame &= (IS_ENABLED(CONFIG_X86_32) ||
+ IS_ENABLED(CONFIG_IA32_EMULATION));
+
+ /*
+ * Only FXSR enabled systems need the FX state quirk.
+ * FRSTOR does not need it and can use the fast path.
+ */
+ if (ia32_frame && use_fxsr()) {
+ buf_fx = buf + sizeof(struct fregs_state);
+ size += sizeof(struct fregs_state);
+ ia32_fxstate = true;
+ }
+
+ if (!access_ok(buf, size))
+ goto out;
+
+ if (!IS_ENABLED(CONFIG_X86_64) && !cpu_feature_enabled(X86_FEATURE_FPU)) {
+ success = !fpregs_soft_set(current, NULL, 0,
+ sizeof(struct user_i387_ia32_struct),
+ NULL, buf);
+ } else {
+ success = __fpu_restore_sig(buf, buf_fx, ia32_fxstate);
+ }
+
+out:
+ if (unlikely(!success))
+ fpu__clear_user_states(fpu);
+ return success;
+}
+
+unsigned long
+fpu__alloc_mathframe(unsigned long sp, int ia32_frame,
+ unsigned long *buf_fx, unsigned long *size)
+{
+ unsigned long frame_size = xstate_sigframe_size(current->thread.fpu.fpstate);
+
+ *buf_fx = sp = round_down(sp - frame_size, 64);
+ if (ia32_frame && use_fxsr()) {
+ frame_size += sizeof(struct fregs_state);
+ sp -= sizeof(struct fregs_state);
+ }
+
+ *size = frame_size;
+
+ return sp;
+}
+
+unsigned long __init fpu__get_fpstate_size(void)
+{
+ unsigned long ret = fpu_user_cfg.max_size;
+
+ if (use_xsave())
+ ret += FP_XSTATE_MAGIC2_SIZE;
+
+ /*
+ * This space is needed on (most) 32-bit kernels, or when a 32-bit
+ * app is running on a 64-bit kernel. To keep things simple, just
+ * assume the worst case and always include space for 'freg_state',
+ * even for 64-bit apps on 64-bit kernels. This wastes a bit of
+ * space, but keeps the code simple.
+ */
+ if ((IS_ENABLED(CONFIG_IA32_EMULATION) ||
+ IS_ENABLED(CONFIG_X86_32)) && use_fxsr())
+ ret += sizeof(struct fregs_state);
+
+ return ret;
+}
+