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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/entry/calling.h
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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/x86/entry/calling.h422
1 files changed, 422 insertions, 0 deletions
diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h
new file mode 100644
index 000000000..f69076271
--- /dev/null
+++ b/arch/x86/entry/calling.h
@@ -0,0 +1,422 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <linux/jump_label.h>
+#include <asm/unwind_hints.h>
+#include <asm/cpufeatures.h>
+#include <asm/page_types.h>
+#include <asm/percpu.h>
+#include <asm/asm-offsets.h>
+#include <asm/processor-flags.h>
+#include <asm/ptrace-abi.h>
+#include <asm/msr.h>
+#include <asm/nospec-branch.h>
+
+/*
+
+ x86 function call convention, 64-bit:
+ -------------------------------------
+ arguments | callee-saved | extra caller-saved | return
+ [callee-clobbered] | | [callee-clobbered] |
+ ---------------------------------------------------------------------------
+ rdi rsi rdx rcx r8-9 | rbx rbp [*] r12-15 | r10-11 | rax, rdx [**]
+
+ ( rsp is obviously invariant across normal function calls. (gcc can 'merge'
+ functions when it sees tail-call optimization possibilities) rflags is
+ clobbered. Leftover arguments are passed over the stack frame.)
+
+ [*] In the frame-pointers case rbp is fixed to the stack frame.
+
+ [**] for struct return values wider than 64 bits the return convention is a
+ bit more complex: up to 128 bits width we return small structures
+ straight in rax, rdx. For structures larger than that (3 words or
+ larger) the caller puts a pointer to an on-stack return struct
+ [allocated in the caller's stack frame] into the first argument - i.e.
+ into rdi. All other arguments shift up by one in this case.
+ Fortunately this case is rare in the kernel.
+
+For 32-bit we have the following conventions - kernel is built with
+-mregparm=3 and -freg-struct-return:
+
+ x86 function calling convention, 32-bit:
+ ----------------------------------------
+ arguments | callee-saved | extra caller-saved | return
+ [callee-clobbered] | | [callee-clobbered] |
+ -------------------------------------------------------------------------
+ eax edx ecx | ebx edi esi ebp [*] | <none> | eax, edx [**]
+
+ ( here too esp is obviously invariant across normal function calls. eflags
+ is clobbered. Leftover arguments are passed over the stack frame. )
+
+ [*] In the frame-pointers case ebp is fixed to the stack frame.
+
+ [**] We build with -freg-struct-return, which on 32-bit means similar
+ semantics as on 64-bit: edx can be used for a second return value
+ (i.e. covering integer and structure sizes up to 64 bits) - after that
+ it gets more complex and more expensive: 3-word or larger struct returns
+ get done in the caller's frame and the pointer to the return struct goes
+ into regparm0, i.e. eax - the other arguments shift up and the
+ function's register parameters degenerate to regparm=2 in essence.
+
+*/
+
+#ifdef CONFIG_X86_64
+
+/*
+ * 64-bit system call stack frame layout defines and helpers,
+ * for assembly code:
+ */
+
+.macro PUSH_REGS rdx=%rdx rcx=%rcx rax=%rax save_ret=0
+ .if \save_ret
+ pushq %rsi /* pt_regs->si */
+ movq 8(%rsp), %rsi /* temporarily store the return address in %rsi */
+ movq %rdi, 8(%rsp) /* pt_regs->di (overwriting original return address) */
+ .else
+ pushq %rdi /* pt_regs->di */
+ pushq %rsi /* pt_regs->si */
+ .endif
+ pushq \rdx /* pt_regs->dx */
+ pushq \rcx /* pt_regs->cx */
+ pushq \rax /* pt_regs->ax */
+ pushq %r8 /* pt_regs->r8 */
+ pushq %r9 /* pt_regs->r9 */
+ pushq %r10 /* pt_regs->r10 */
+ pushq %r11 /* pt_regs->r11 */
+ pushq %rbx /* pt_regs->rbx */
+ pushq %rbp /* pt_regs->rbp */
+ pushq %r12 /* pt_regs->r12 */
+ pushq %r13 /* pt_regs->r13 */
+ pushq %r14 /* pt_regs->r14 */
+ pushq %r15 /* pt_regs->r15 */
+ UNWIND_HINT_REGS
+
+ .if \save_ret
+ pushq %rsi /* return address on top of stack */
+ .endif
+.endm
+
+.macro CLEAR_REGS
+ /*
+ * Sanitize registers of values that a speculation attack might
+ * otherwise want to exploit. The lower registers are likely clobbered
+ * well before they could be put to use in a speculative execution
+ * gadget.
+ */
+ xorl %esi, %esi /* nospec si */
+ xorl %edx, %edx /* nospec dx */
+ xorl %ecx, %ecx /* nospec cx */
+ xorl %r8d, %r8d /* nospec r8 */
+ xorl %r9d, %r9d /* nospec r9 */
+ xorl %r10d, %r10d /* nospec r10 */
+ xorl %r11d, %r11d /* nospec r11 */
+ xorl %ebx, %ebx /* nospec rbx */
+ xorl %ebp, %ebp /* nospec rbp */
+ xorl %r12d, %r12d /* nospec r12 */
+ xorl %r13d, %r13d /* nospec r13 */
+ xorl %r14d, %r14d /* nospec r14 */
+ xorl %r15d, %r15d /* nospec r15 */
+
+.endm
+
+.macro PUSH_AND_CLEAR_REGS rdx=%rdx rcx=%rcx rax=%rax save_ret=0
+ PUSH_REGS rdx=\rdx, rcx=\rcx, rax=\rax, save_ret=\save_ret
+ CLEAR_REGS
+.endm
+
+.macro POP_REGS pop_rdi=1
+ popq %r15
+ popq %r14
+ popq %r13
+ popq %r12
+ popq %rbp
+ popq %rbx
+ popq %r11
+ popq %r10
+ popq %r9
+ popq %r8
+ popq %rax
+ popq %rcx
+ popq %rdx
+ popq %rsi
+ .if \pop_rdi
+ popq %rdi
+ .endif
+.endm
+
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
+
+/*
+ * PAGE_TABLE_ISOLATION PGDs are 8k. Flip bit 12 to switch between the two
+ * halves:
+ */
+#define PTI_USER_PGTABLE_BIT PAGE_SHIFT
+#define PTI_USER_PGTABLE_MASK (1 << PTI_USER_PGTABLE_BIT)
+#define PTI_USER_PCID_BIT X86_CR3_PTI_PCID_USER_BIT
+#define PTI_USER_PCID_MASK (1 << PTI_USER_PCID_BIT)
+#define PTI_USER_PGTABLE_AND_PCID_MASK (PTI_USER_PCID_MASK | PTI_USER_PGTABLE_MASK)
+
+.macro SET_NOFLUSH_BIT reg:req
+ bts $X86_CR3_PCID_NOFLUSH_BIT, \reg
+.endm
+
+.macro ADJUST_KERNEL_CR3 reg:req
+ ALTERNATIVE "", "SET_NOFLUSH_BIT \reg", X86_FEATURE_PCID
+ /* Clear PCID and "PAGE_TABLE_ISOLATION bit", point CR3 at kernel pagetables: */
+ andq $(~PTI_USER_PGTABLE_AND_PCID_MASK), \reg
+.endm
+
+.macro SWITCH_TO_KERNEL_CR3 scratch_reg:req
+ ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_PTI
+ mov %cr3, \scratch_reg
+ ADJUST_KERNEL_CR3 \scratch_reg
+ mov \scratch_reg, %cr3
+.Lend_\@:
+.endm
+
+#define THIS_CPU_user_pcid_flush_mask \
+ PER_CPU_VAR(cpu_tlbstate) + TLB_STATE_user_pcid_flush_mask
+
+.macro SWITCH_TO_USER_CR3_NOSTACK scratch_reg:req scratch_reg2:req
+ ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_PTI
+ mov %cr3, \scratch_reg
+
+ ALTERNATIVE "jmp .Lwrcr3_\@", "", X86_FEATURE_PCID
+
+ /*
+ * Test if the ASID needs a flush.
+ */
+ movq \scratch_reg, \scratch_reg2
+ andq $(0x7FF), \scratch_reg /* mask ASID */
+ bt \scratch_reg, THIS_CPU_user_pcid_flush_mask
+ jnc .Lnoflush_\@
+
+ /* Flush needed, clear the bit */
+ btr \scratch_reg, THIS_CPU_user_pcid_flush_mask
+ movq \scratch_reg2, \scratch_reg
+ jmp .Lwrcr3_pcid_\@
+
+.Lnoflush_\@:
+ movq \scratch_reg2, \scratch_reg
+ SET_NOFLUSH_BIT \scratch_reg
+
+.Lwrcr3_pcid_\@:
+ /* Flip the ASID to the user version */
+ orq $(PTI_USER_PCID_MASK), \scratch_reg
+
+.Lwrcr3_\@:
+ /* Flip the PGD to the user version */
+ orq $(PTI_USER_PGTABLE_MASK), \scratch_reg
+ mov \scratch_reg, %cr3
+.Lend_\@:
+.endm
+
+.macro SWITCH_TO_USER_CR3_STACK scratch_reg:req
+ pushq %rax
+ SWITCH_TO_USER_CR3_NOSTACK scratch_reg=\scratch_reg scratch_reg2=%rax
+ popq %rax
+.endm
+
+.macro SAVE_AND_SWITCH_TO_KERNEL_CR3 scratch_reg:req save_reg:req
+ ALTERNATIVE "jmp .Ldone_\@", "", X86_FEATURE_PTI
+ movq %cr3, \scratch_reg
+ movq \scratch_reg, \save_reg
+ /*
+ * Test the user pagetable bit. If set, then the user page tables
+ * are active. If clear CR3 already has the kernel page table
+ * active.
+ */
+ bt $PTI_USER_PGTABLE_BIT, \scratch_reg
+ jnc .Ldone_\@
+
+ ADJUST_KERNEL_CR3 \scratch_reg
+ movq \scratch_reg, %cr3
+
+.Ldone_\@:
+.endm
+
+.macro RESTORE_CR3 scratch_reg:req save_reg:req
+ ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_PTI
+
+ ALTERNATIVE "jmp .Lwrcr3_\@", "", X86_FEATURE_PCID
+
+ /*
+ * KERNEL pages can always resume with NOFLUSH as we do
+ * explicit flushes.
+ */
+ bt $PTI_USER_PGTABLE_BIT, \save_reg
+ jnc .Lnoflush_\@
+
+ /*
+ * Check if there's a pending flush for the user ASID we're
+ * about to set.
+ */
+ movq \save_reg, \scratch_reg
+ andq $(0x7FF), \scratch_reg
+ bt \scratch_reg, THIS_CPU_user_pcid_flush_mask
+ jnc .Lnoflush_\@
+
+ btr \scratch_reg, THIS_CPU_user_pcid_flush_mask
+ jmp .Lwrcr3_\@
+
+.Lnoflush_\@:
+ SET_NOFLUSH_BIT \save_reg
+
+.Lwrcr3_\@:
+ /*
+ * The CR3 write could be avoided when not changing its value,
+ * but would require a CR3 read *and* a scratch register.
+ */
+ movq \save_reg, %cr3
+.Lend_\@:
+.endm
+
+#else /* CONFIG_PAGE_TABLE_ISOLATION=n: */
+
+.macro SWITCH_TO_KERNEL_CR3 scratch_reg:req
+.endm
+.macro SWITCH_TO_USER_CR3_NOSTACK scratch_reg:req scratch_reg2:req
+.endm
+.macro SWITCH_TO_USER_CR3_STACK scratch_reg:req
+.endm
+.macro SAVE_AND_SWITCH_TO_KERNEL_CR3 scratch_reg:req save_reg:req
+.endm
+.macro RESTORE_CR3 scratch_reg:req save_reg:req
+.endm
+
+#endif
+
+/*
+ * IBRS kernel mitigation for Spectre_v2.
+ *
+ * Assumes full context is established (PUSH_REGS, CR3 and GS) and it clobbers
+ * the regs it uses (AX, CX, DX). Must be called before the first RET
+ * instruction (NOTE! UNTRAIN_RET includes a RET instruction)
+ *
+ * The optional argument is used to save/restore the current value,
+ * which is used on the paranoid paths.
+ *
+ * Assumes x86_spec_ctrl_{base,current} to have SPEC_CTRL_IBRS set.
+ */
+.macro IBRS_ENTER save_reg
+#ifdef CONFIG_CPU_IBRS_ENTRY
+ ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_KERNEL_IBRS
+ movl $MSR_IA32_SPEC_CTRL, %ecx
+
+.ifnb \save_reg
+ rdmsr
+ shl $32, %rdx
+ or %rdx, %rax
+ mov %rax, \save_reg
+ test $SPEC_CTRL_IBRS, %eax
+ jz .Ldo_wrmsr_\@
+ lfence
+ jmp .Lend_\@
+.Ldo_wrmsr_\@:
+.endif
+
+ movq PER_CPU_VAR(x86_spec_ctrl_current), %rdx
+ movl %edx, %eax
+ shr $32, %rdx
+ wrmsr
+.Lend_\@:
+#endif
+.endm
+
+/*
+ * Similar to IBRS_ENTER, requires KERNEL GS,CR3 and clobbers (AX, CX, DX)
+ * regs. Must be called after the last RET.
+ */
+.macro IBRS_EXIT save_reg
+#ifdef CONFIG_CPU_IBRS_ENTRY
+ ALTERNATIVE "jmp .Lend_\@", "", X86_FEATURE_KERNEL_IBRS
+ movl $MSR_IA32_SPEC_CTRL, %ecx
+
+.ifnb \save_reg
+ mov \save_reg, %rdx
+.else
+ movq PER_CPU_VAR(x86_spec_ctrl_current), %rdx
+ andl $(~SPEC_CTRL_IBRS), %edx
+.endif
+
+ movl %edx, %eax
+ shr $32, %rdx
+ wrmsr
+.Lend_\@:
+#endif
+.endm
+
+/*
+ * Mitigate Spectre v1 for conditional swapgs code paths.
+ *
+ * FENCE_SWAPGS_USER_ENTRY is used in the user entry swapgs code path, to
+ * prevent a speculative swapgs when coming from kernel space.
+ *
+ * FENCE_SWAPGS_KERNEL_ENTRY is used in the kernel entry non-swapgs code path,
+ * to prevent the swapgs from getting speculatively skipped when coming from
+ * user space.
+ */
+.macro FENCE_SWAPGS_USER_ENTRY
+ ALTERNATIVE "", "lfence", X86_FEATURE_FENCE_SWAPGS_USER
+.endm
+.macro FENCE_SWAPGS_KERNEL_ENTRY
+ ALTERNATIVE "", "lfence", X86_FEATURE_FENCE_SWAPGS_KERNEL
+.endm
+
+.macro STACKLEAK_ERASE_NOCLOBBER
+#ifdef CONFIG_GCC_PLUGIN_STACKLEAK
+ PUSH_AND_CLEAR_REGS
+ call stackleak_erase
+ POP_REGS
+#endif
+.endm
+
+.macro SAVE_AND_SET_GSBASE scratch_reg:req save_reg:req
+ rdgsbase \save_reg
+ GET_PERCPU_BASE \scratch_reg
+ wrgsbase \scratch_reg
+.endm
+
+#else /* CONFIG_X86_64 */
+# undef UNWIND_HINT_IRET_REGS
+# define UNWIND_HINT_IRET_REGS
+#endif /* !CONFIG_X86_64 */
+
+.macro STACKLEAK_ERASE
+#ifdef CONFIG_GCC_PLUGIN_STACKLEAK
+ call stackleak_erase
+#endif
+.endm
+
+#ifdef CONFIG_SMP
+
+/*
+ * CPU/node NR is loaded from the limit (size) field of a special segment
+ * descriptor entry in GDT.
+ */
+.macro LOAD_CPU_AND_NODE_SEG_LIMIT reg:req
+ movq $__CPUNODE_SEG, \reg
+ lsl \reg, \reg
+.endm
+
+/*
+ * Fetch the per-CPU GSBASE value for this processor and put it in @reg.
+ * We normally use %gs for accessing per-CPU data, but we are setting up
+ * %gs here and obviously can not use %gs itself to access per-CPU data.
+ *
+ * Do not use RDPID, because KVM loads guest's TSC_AUX on vm-entry and
+ * may not restore the host's value until the CPU returns to userspace.
+ * Thus the kernel would consume a guest's TSC_AUX if an NMI arrives
+ * while running KVM's run loop.
+ */
+.macro GET_PERCPU_BASE reg:req
+ LOAD_CPU_AND_NODE_SEG_LIMIT \reg
+ andq $VDSO_CPUNODE_MASK, \reg
+ movq __per_cpu_offset(, \reg, 8), \reg
+.endm
+
+#else
+
+.macro GET_PERCPU_BASE reg:req
+ movq pcpu_unit_offsets(%rip), \reg
+.endm
+
+#endif /* CONFIG_SMP */