17 files changed, 273 insertions, 368 deletions

diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h
index efb0d1b1f15f..9f1f9e3b8230 100644
--- a/arch/x86/entry/calling.h
+++ b/arch/x86/entry/calling.h
@@ -172,21 +172,6 @@ For 32-bit we have the following conventions - kernel is built with
 	.endif
 .endm
 
-/*
- * This is a sneaky trick to help the unwinder find pt_regs on the stack.  The
- * frame pointer is replaced with an encoded pointer to pt_regs.  The encoding
- * is just setting the LSB, which makes it an invalid stack address and is also
- * a signal to the unwinder that it's a pt_regs pointer in disguise.
- *
- * NOTE: This macro must be used *after* PUSH_AND_CLEAR_REGS because it corrupts
- * the original rbp.
- */
-.macro ENCODE_FRAME_POINTER ptregs_offset=0
-#ifdef CONFIG_FRAME_POINTER
-	leaq 1+\ptregs_offset(%rsp), %rbp
-#endif
-.endm
-
 #ifdef CONFIG_PAGE_TABLE_ISOLATION
 
 /*
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index a986b3c8294c..536b574b6161 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -1,7 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * common.c - C code for kernel entry and exit
  * Copyright (c) 2015 Andrew Lutomirski
- * GPL v2
  *
  * Based on asm and ptrace code by many authors.  The code here originated
  * in ptrace.c and signal.c.
@@ -72,23 +72,18 @@ static long syscall_trace_enter(struct pt_regs *regs)
 
 	struct thread_info *ti = current_thread_info();
 	unsigned long ret = 0;
-	bool emulated = false;
 	u32 work;
 
 	if (IS_ENABLED(CONFIG_DEBUG_ENTRY))
 		BUG_ON(regs != task_pt_regs(current));
 
-	work = READ_ONCE(ti->flags) & _TIF_WORK_SYSCALL_ENTRY;
+	work = READ_ONCE(ti->flags);
 
-	if (unlikely(work & _TIF_SYSCALL_EMU))
-		emulated = true;
-
-	if ((emulated || (work & _TIF_SYSCALL_TRACE)) &&
-	    tracehook_report_syscall_entry(regs))
-		return -1L;
-
-	if (emulated)
-		return -1L;
+	if (work & (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU)) {
+		ret = tracehook_report_syscall_entry(regs);
+		if (ret || (work & _TIF_SYSCALL_EMU))
+			return -1L;
+	}
 
 #ifdef CONFIG_SECCOMP
 	/*
diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index 7b23431be5cb..1285e5abf669 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -67,7 +67,6 @@
 # define preempt_stop(clobbers)	DISABLE_INTERRUPTS(clobbers); TRACE_IRQS_OFF
 #else
 # define preempt_stop(clobbers)
-# define resume_kernel		restore_all_kernel
 #endif
 
 .macro TRACE_IRQS_IRET
@@ -203,9 +202,102 @@
 .Lend_\@:
 .endm
 
+#define CS_FROM_ENTRY_STACK	(1 << 31)
+#define CS_FROM_USER_CR3	(1 << 30)
+#define CS_FROM_KERNEL		(1 << 29)
+
+.macro FIXUP_FRAME
+	/*
+	 * The high bits of the CS dword (__csh) are used for CS_FROM_*.
+	 * Clear them in case hardware didn't do this for us.
+	 */
+	andl	$0x0000ffff, 3*4(%esp)
+
+#ifdef CONFIG_VM86
+	testl	$X86_EFLAGS_VM, 4*4(%esp)
+	jnz	.Lfrom_usermode_no_fixup_\@
+#endif
+	testl	$SEGMENT_RPL_MASK, 3*4(%esp)
+	jnz	.Lfrom_usermode_no_fixup_\@
+
+	orl	$CS_FROM_KERNEL, 3*4(%esp)
+
+	/*
+	 * When we're here from kernel mode; the (exception) stack looks like:
+	 *
+	 *  5*4(%esp) - <previous context>
+	 *  4*4(%esp) - flags
+	 *  3*4(%esp) - cs
+	 *  2*4(%esp) - ip
+	 *  1*4(%esp) - orig_eax
+	 *  0*4(%esp) - gs / function
+	 *
+	 * Lets build a 5 entry IRET frame after that, such that struct pt_regs
+	 * is complete and in particular regs->sp is correct. This gives us
+	 * the original 5 enties as gap:
+	 *
+	 * 12*4(%esp) - <previous context>
+	 * 11*4(%esp) - gap / flags
+	 * 10*4(%esp) - gap / cs
+	 *  9*4(%esp) - gap / ip
+	 *  8*4(%esp) - gap / orig_eax
+	 *  7*4(%esp) - gap / gs / function
+	 *  6*4(%esp) - ss
+	 *  5*4(%esp) - sp
+	 *  4*4(%esp) - flags
+	 *  3*4(%esp) - cs
+	 *  2*4(%esp) - ip
+	 *  1*4(%esp) - orig_eax
+	 *  0*4(%esp) - gs / function
+	 */
+
+	pushl	%ss		# ss
+	pushl	%esp		# sp (points at ss)
+	addl	$6*4, (%esp)	# point sp back at the previous context
+	pushl	6*4(%esp)	# flags
+	pushl	6*4(%esp)	# cs
+	pushl	6*4(%esp)	# ip
+	pushl	6*4(%esp)	# orig_eax
+	pushl	6*4(%esp)	# gs / function
+.Lfrom_usermode_no_fixup_\@:
+.endm
+
+.macro IRET_FRAME
+	testl $CS_FROM_KERNEL, 1*4(%esp)
+	jz .Lfinished_frame_\@
+
+	/*
+	 * Reconstruct the 3 entry IRET frame right after the (modified)
+	 * regs->sp without lowering %esp in between, such that an NMI in the
+	 * middle doesn't scribble our stack.
+	 */
+	pushl	%eax
+	pushl	%ecx
+	movl	5*4(%esp), %eax		# (modified) regs->sp
+
+	movl	4*4(%esp), %ecx		# flags
+	movl	%ecx, -4(%eax)
+
+	movl	3*4(%esp), %ecx		# cs
+	andl	$0x0000ffff, %ecx
+	movl	%ecx, -8(%eax)
+
+	movl	2*4(%esp), %ecx		# ip
+	movl	%ecx, -12(%eax)
+
+	movl	1*4(%esp), %ecx		# eax
+	movl	%ecx, -16(%eax)
+
+	popl	%ecx
+	lea	-16(%eax), %esp
+	popl	%eax
+.Lfinished_frame_\@:
+.endm
+
 .macro SAVE_ALL pt_regs_ax=%eax switch_stacks=0
 	cld
 	PUSH_GS
+	FIXUP_FRAME
 	pushl	%fs
 	pushl	%es
 	pushl	%ds
@@ -247,22 +339,6 @@
 .Lend_\@:
 .endm
 
-/*
- * This is a sneaky trick to help the unwinder find pt_regs on the stack.  The
- * frame pointer is replaced with an encoded pointer to pt_regs.  The encoding
- * is just clearing the MSB, which makes it an invalid stack address and is also
- * a signal to the unwinder that it's a pt_regs pointer in disguise.
- *
- * NOTE: This macro must be used *after* SAVE_ALL because it corrupts the
- * original rbp.
- */
-.macro ENCODE_FRAME_POINTER
-#ifdef CONFIG_FRAME_POINTER
-	mov %esp, %ebp
-	andl $0x7fffffff, %ebp
-#endif
-.endm
-
 .macro RESTORE_INT_REGS
 	popl	%ebx
 	popl	%ecx
@@ -375,9 +451,6 @@
  * switch to it before we do any copying.
  */
 
-#define CS_FROM_ENTRY_STACK	(1 << 31)
-#define CS_FROM_USER_CR3	(1 << 30)
-
 .macro SWITCH_TO_KERNEL_STACK
 
 	ALTERNATIVE     "", "jmp .Lend_\@", X86_FEATURE_XENPV
@@ -391,13 +464,6 @@
 	 * that register for the time this macro runs
 	 */
 
-	/*
-	 * The high bits of the CS dword (__csh) are used for
-	 * CS_FROM_ENTRY_STACK and CS_FROM_USER_CR3. Clear them in case
-	 * hardware didn't do this for us.
-	 */
-	andl	$(0x0000ffff), PT_CS(%esp)
-
 	/* Are we on the entry stack? Bail out if not! */
 	movl	PER_CPU_VAR(cpu_entry_area), %ecx
 	addl	$CPU_ENTRY_AREA_entry_stack + SIZEOF_entry_stack, %ecx
@@ -755,7 +821,7 @@ ret_from_intr:
 	andl	$SEGMENT_RPL_MASK, %eax
 #endif
 	cmpl	$USER_RPL, %eax
-	jb	resume_kernel			# not returning to v8086 or userspace
+	jb	restore_all_kernel		# not returning to v8086 or userspace
 
 ENTRY(resume_userspace)
 	DISABLE_INTERRUPTS(CLBR_ANY)
@@ -765,18 +831,6 @@ ENTRY(resume_userspace)
 	jmp	restore_all
 END(ret_from_exception)
 
-#ifdef CONFIG_PREEMPT
-ENTRY(resume_kernel)
-	DISABLE_INTERRUPTS(CLBR_ANY)
-	cmpl	$0, PER_CPU_VAR(__preempt_count)
-	jnz	restore_all_kernel
-	testl	$X86_EFLAGS_IF, PT_EFLAGS(%esp)	# interrupts off (exception path) ?
-	jz	restore_all_kernel
-	call	preempt_schedule_irq
-	jmp	restore_all_kernel
-END(resume_kernel)
-#endif
-
 GLOBAL(__begin_SYSENTER_singlestep_region)
 /*
  * All code from here through __end_SYSENTER_singlestep_region is subject
@@ -1019,6 +1073,7 @@ restore_all:
 	/* Restore user state */
 	RESTORE_REGS pop=4			# skip orig_eax/error_code
 .Lirq_return:
+	IRET_FRAME
 	/*
 	 * ARCH_HAS_MEMBARRIER_SYNC_CORE rely on IRET core serialization
 	 * when returning from IPI handler and when returning from
@@ -1027,6 +1082,15 @@ restore_all:
 	INTERRUPT_RETURN
 
 restore_all_kernel:
+#ifdef CONFIG_PREEMPT
+	DISABLE_INTERRUPTS(CLBR_ANY)
+	cmpl	$0, PER_CPU_VAR(__preempt_count)
+	jnz	.Lno_preempt
+	testl	$X86_EFLAGS_IF, PT_EFLAGS(%esp)	# interrupts off (exception path) ?
+	jz	.Lno_preempt
+	call	preempt_schedule_irq
+.Lno_preempt:
+#endif
 	TRACE_IRQS_IRET
 	PARANOID_EXIT_TO_KERNEL_MODE
 	BUG_IF_WRONG_CR3
@@ -1104,6 +1168,30 @@ ENTRY(irq_entries_start)
     .endr
 END(irq_entries_start)
 
+#ifdef CONFIG_X86_LOCAL_APIC
+	.align 8
+ENTRY(spurious_entries_start)
+    vector=FIRST_SYSTEM_VECTOR
+    .rept (NR_VECTORS - FIRST_SYSTEM_VECTOR)
+	pushl	$(~vector+0x80)			/* Note: always in signed byte range */
+    vector=vector+1
+	jmp	common_spurious
+	.align	8
+    .endr
+END(spurious_entries_start)
+
+common_spurious:
+	ASM_CLAC
+	addl	$-0x80, (%esp)			/* Adjust vector into the [-256, -1] range */
+	SAVE_ALL switch_stacks=1
+	ENCODE_FRAME_POINTER
+	TRACE_IRQS_OFF
+	movl	%esp, %eax
+	call	smp_spurious_interrupt
+	jmp	ret_from_intr
+ENDPROC(common_interrupt)
+#endif
+
 /*
  * the CPU automatically disables interrupts when executing an IRQ vector,
  * so IRQ-flags tracing has to follow that:
@@ -1360,6 +1448,7 @@ END(page_fault)
 
 common_exception:
 	/* the function address is in %gs's slot on the stack */
+	FIXUP_FRAME
 	pushl	%fs
 	pushl	%es
 	pushl	%ds
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 11aa3b2afa4d..a829dd3117d0 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -375,6 +375,18 @@ ENTRY(irq_entries_start)
     .endr
 END(irq_entries_start)
 
+	.align 8
+ENTRY(spurious_entries_start)
+    vector=FIRST_SYSTEM_VECTOR
+    .rept (NR_VECTORS - FIRST_SYSTEM_VECTOR)
+	UNWIND_HINT_IRET_REGS
+	pushq	$(~vector+0x80)			/* Note: always in signed byte range */
+	jmp	common_spurious
+	.align	8
+	vector=vector+1
+    .endr
+END(spurious_entries_start)
+
 .macro DEBUG_ENTRY_ASSERT_IRQS_OFF
 #ifdef CONFIG_DEBUG_ENTRY
 	pushq %rax
@@ -571,10 +583,20 @@ _ASM_NOKPROBE(interrupt_entry)
 
 /* Interrupt entry/exit. */
 
-	/*
-	 * The interrupt stubs push (~vector+0x80) onto the stack and
-	 * then jump to common_interrupt.
-	 */
+/*
+ * The interrupt stubs push (~vector+0x80) onto the stack and
+ * then jump to common_spurious/interrupt.
+ */
+common_spurious:
+	addq	$-0x80, (%rsp)			/* Adjust vector to [-256, -1] range */
+	call	interrupt_entry
+	UNWIND_HINT_REGS indirect=1
+	call	smp_spurious_interrupt		/* rdi points to pt_regs */
+	jmp	ret_from_intr
+END(common_spurious)
+_ASM_NOKPROBE(common_spurious)
+
+/* common_interrupt is a hotpath. Align it */
 	.p2align CONFIG_X86_L1_CACHE_SHIFT
 common_interrupt:
 	addq	$-0x80, (%rsp)			/* Adjust vector to [-256, -1] range */
@@ -1142,6 +1164,11 @@ apicinterrupt3 HYPERV_STIMER0_VECTOR \
 	hv_stimer0_callback_vector hv_stimer0_vector_handler
 #endif /* CONFIG_HYPERV */
 
+#if IS_ENABLED(CONFIG_ACRN_GUEST)
+apicinterrupt3 HYPERVISOR_CALLBACK_VECTOR \
+	acrn_hv_callback_vector acrn_hv_vector_handler
+#endif
+
 idtentry debug			do_debug		has_error_code=0	paranoid=1 shift_ist=IST_INDEX_DB ist_offset=DB_STACK_OFFSET
 idtentry int3			do_int3			has_error_code=0	create_gap=1
 idtentry stack_segment		do_stack_segment	has_error_code=1
@@ -1670,11 +1697,17 @@ nmi_restore:
 	iretq
 END(nmi)
 
+#ifndef CONFIG_IA32_EMULATION
+/*
+ * This handles SYSCALL from 32-bit code.  There is no way to program
+ * MSRs to fully disable 32-bit SYSCALL.
+ */
 ENTRY(ignore_sysret)
 	UNWIND_HINT_EMPTY
 	mov	$-ENOSYS, %eax
 	sysret
 END(ignore_sysret)
+#endif
 
 ENTRY(rewind_stack_do_exit)
 	UNWIND_HINT_FUNC
diff --git a/arch/x86/entry/thunk_32.S b/arch/x86/entry/thunk_32.S
index fee6bc79b987..cb3464525b37 100644
--- a/arch/x86/entry/thunk_32.S
+++ b/arch/x86/entry/thunk_32.S
@@ -1,8 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * Trampoline to trace irqs off. (otherwise CALLER_ADDR1 might crash)
  * Copyright 2008 by Steven Rostedt, Red Hat, Inc
  *  (inspired by Andi Kleen's thunk_64.S)
- * Subject to the GNU public license, v.2. No warranty of any kind.
  */
 	#include <linux/linkage.h>
 	#include <asm/asm.h>
diff --git a/arch/x86/entry/thunk_64.S b/arch/x86/entry/thunk_64.S
index be36bf4e0957..cfdca8b42c70 100644
--- a/arch/x86/entry/thunk_64.S
+++ b/arch/x86/entry/thunk_64.S
@@ -1,9 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * Save registers before calling assembly functions. This avoids
  * disturbance of register allocation in some inline assembly constructs.
  * Copyright 2001,2002 by Andi Kleen, SuSE Labs.
  * Added trace_hardirqs callers - Copyright 2007 Steven Rostedt, Red Hat, Inc.
- * Subject to the GNU public license, v.2. No warranty of any kind.
  */
 #include <linux/linkage.h>
 #include "calling.h"
diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index 42fe42e82baf..39106111be86 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -3,6 +3,12 @@
 # Building vDSO images for x86.
 #
 
+# Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before
+# the inclusion of generic Makefile.
+ARCH_REL_TYPE_ABS := R_X86_64_JUMP_SLOT|R_X86_64_GLOB_DAT|R_X86_64_RELATIVE|
+ARCH_REL_TYPE_ABS += R_386_GLOB_DAT|R_386_JMP_SLOT|R_386_RELATIVE
+include $(srctree)/lib/vdso/Makefile
+
 KBUILD_CFLAGS += $(DISABLE_LTO)
 KASAN_SANITIZE			:= n
 UBSAN_SANITIZE			:= n
@@ -51,6 +57,7 @@ VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 --no-undefined \
 
 $(obj)/vdso64.so.dbg: $(obj)/vdso.lds $(vobjs) FORCE
 	$(call if_changed,vdso)
+	$(call if_changed,vdso_check)
 
 HOST_EXTRACFLAGS += -I$(srctree)/tools/include -I$(srctree)/include/uapi -I$(srctree)/arch/$(SUBARCH)/include/uapi
 hostprogs-y			+= vdso2c
@@ -121,6 +128,7 @@ $(obj)/%.so: $(obj)/%.so.dbg FORCE
 
 $(obj)/vdsox32.so.dbg: $(obj)/vdsox32.lds $(vobjx32s) FORCE
 	$(call if_changed,vdso)
+	$(call if_changed,vdso_check)
 
 CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds)
 VDSO_LDFLAGS_vdso32.lds = -m elf_i386 -soname linux-gate.so.1
@@ -160,6 +168,7 @@ $(obj)/vdso32.so.dbg: FORCE \
 		      $(obj)/vdso32/system_call.o \
 		      $(obj)/vdso32/sigreturn.o
 	$(call if_changed,vdso)
+	$(call if_changed,vdso_check)
 
 #
 # The DSO images are built using a special linker script.
diff --git a/arch/x86/entry/vdso/vclock_gettime.c b/arch/x86/entry/vdso/vclock_gettime.c
index 98c7d12b945c..d9ff616bb0f6 100644
--- a/arch/x86/entry/vdso/vclock_gettime.c
+++ b/arch/x86/entry/vdso/vclock_gettime.c
@@ -1,240 +1,85 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
- * Copyright 2006 Andi Kleen, SUSE Labs.
- * Subject to the GNU Public License, v.2
- *
  * Fast user context implementation of clock_gettime, gettimeofday, and time.
  *
+ * Copyright 2006 Andi Kleen, SUSE Labs.
+ * Copyright 2019 ARM Limited
+ *
  * 32 Bit compat layer by Stefani Seibold <stefani@seibold.net>
  *  sponsored by Rohde & Schwarz GmbH & Co. KG Munich/Germany
- *
- * The code should have no internal unresolved relocations.
- * Check with readelf after changing.
  */
-
-#include <uapi/linux/time.h>
-#include <asm/vgtod.h>
-#include <asm/vvar.h>
-#include <asm/unistd.h>
-#include <asm/msr.h>
-#include <asm/pvclock.h>
-#include <asm/mshyperv.h>
-#include <linux/math64.h>
 #include <linux/time.h>
 #include <linux/kernel.h>
+#include <linux/types.h>
 
-#define gtod (&VVAR(vsyscall_gtod_data))
+#include "../../../../lib/vdso/gettimeofday.c"
 
-extern int __vdso_clock_gettime(clockid_t clock, struct timespec *ts);
-extern int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz);
+extern int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz);
 extern time_t __vdso_time(time_t *t);
 
-#ifdef CONFIG_PARAVIRT_CLOCK
-extern u8 pvclock_page[PAGE_SIZE]
-	__attribute__((visibility("hidden")));
-#endif
-
-#ifdef CONFIG_HYPERV_TSCPAGE
-extern u8 hvclock_page[PAGE_SIZE]
-	__attribute__((visibility("hidden")));
-#endif
-
-#ifndef BUILD_VDSO32
-
-notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
+int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
 {
-	long ret;
-	asm ("syscall" : "=a" (ret), "=m" (*ts) :
-	     "0" (__NR_clock_gettime), "D" (clock), "S" (ts) :
-	     "rcx", "r11");
-	return ret;
+	return __cvdso_gettimeofday(tv, tz);
 }
 
-#else
+int gettimeofday(struct __kernel_old_timeval *, struct timezone *)
+	__attribute__((weak, alias("__vdso_gettimeofday")));
 
-notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
+time_t __vdso_time(time_t *t)
 {
-	long ret;
-
-	asm (
-		"mov %%ebx, %%edx \n"
-		"mov %[clock], %%ebx \n"
-		"call __kernel_vsyscall \n"
-		"mov %%edx, %%ebx \n"
-		: "=a" (ret), "=m" (*ts)
-		: "0" (__NR_clock_gettime), [clock] "g" (clock), "c" (ts)
-		: "edx");
-	return ret;
+	return __cvdso_time(t);
 }
 
-#endif
+time_t time(time_t *t)	__attribute__((weak, alias("__vdso_time")));
 
-#ifdef CONFIG_PARAVIRT_CLOCK
-static notrace const struct pvclock_vsyscall_time_info *get_pvti0(void)
-{
-	return (const struct pvclock_vsyscall_time_info *)&pvclock_page;
-}
 
-static notrace u64 vread_pvclock(void)
-{
-	const struct pvclock_vcpu_time_info *pvti = &get_pvti0()->pvti;
-	u32 version;
-	u64 ret;
-
-	/*
-	 * Note: The kernel and hypervisor must guarantee that cpu ID
-	 * number maps 1:1 to per-CPU pvclock time info.
-	 *
-	 * Because the hypervisor is entirely unaware of guest userspace
-	 * preemption, it cannot guarantee that per-CPU pvclock time
-	 * info is updated if the underlying CPU changes or that that
-	 * version is increased whenever underlying CPU changes.
-	 *
-	 * On KVM, we are guaranteed that pvti updates for any vCPU are
-	 * atomic as seen by *all* vCPUs.  This is an even stronger
-	 * guarantee than we get with a normal seqlock.
-	 *
-	 * On Xen, we don't appear to have that guarantee, but Xen still
-	 * supplies a valid seqlock using the version field.
-	 *
-	 * We only do pvclock vdso timing at all if
-	 * PVCLOCK_TSC_STABLE_BIT is set, and we interpret that bit to
-	 * mean that all vCPUs have matching pvti and that the TSC is
-	 * synced, so we can just look at vCPU 0's pvti.
-	 */
-
-	do {
-		version = pvclock_read_begin(pvti);
-
-		if (unlikely(!(pvti->flags & PVCLOCK_TSC_STABLE_BIT)))
-			return U64_MAX;
-
-		ret = __pvclock_read_cycles(pvti, rdtsc_ordered());
-	} while (pvclock_read_retry(pvti, version));
-
-	return ret;
-}
-#endif
-#ifdef CONFIG_HYPERV_TSCPAGE
-static notrace u64 vread_hvclock(void)
-{
-	const struct ms_hyperv_tsc_page *tsc_pg =
-		(const struct ms_hyperv_tsc_page *)&hvclock_page;
+#if defined(CONFIG_X86_64) && !defined(BUILD_VDSO32_64)
+/* both 64-bit and x32 use these */
+extern int __vdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts);
+extern int __vdso_clock_getres(clockid_t clock, struct __kernel_timespec *res);
 
-	return hv_read_tsc_page(tsc_pg);
-}
-#endif
-
-notrace static inline u64 vgetcyc(int mode)
+int __vdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts)
 {
-	if (mode == VCLOCK_TSC)
-		return (u64)rdtsc_ordered();
-#ifdef CONFIG_PARAVIRT_CLOCK
-	else if (mode == VCLOCK_PVCLOCK)
-		return vread_pvclock();
-#endif
-#ifdef CONFIG_HYPERV_TSCPAGE
-	else if (mode == VCLOCK_HVCLOCK)
-		return vread_hvclock();
-#endif
-	return U64_MAX;
+	return __cvdso_clock_gettime(clock, ts);
 }
 
-notrace static int do_hres(clockid_t clk, struct timespec *ts)
-{
-	struct vgtod_ts *base = &gtod->basetime[clk];
-	u64 cycles, last, sec, ns;
-	unsigned int seq;
-
-	do {
-		seq = gtod_read_begin(gtod);
-		cycles = vgetcyc(gtod->vclock_mode);
-		ns = base->nsec;
-		last = gtod->cycle_last;
-		if (unlikely((s64)cycles < 0))
-			return vdso_fallback_gettime(clk, ts);
-		if (cycles > last)
-			ns += (cycles - last) * gtod->mult;
-		ns >>= gtod->shift;
-		sec = base->sec;
-	} while (unlikely(gtod_read_retry(gtod, seq)));
-
-	/*
-	 * Do this outside the loop: a race inside the loop could result
-	 * in __iter_div_u64_rem() being extremely slow.
-	 */
-	ts->tv_sec = sec + __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
-	ts->tv_nsec = ns;
-
-	return 0;
-}
+int clock_gettime(clockid_t, struct __kernel_timespec *)
+	__attribute__((weak, alias("__vdso_clock_gettime")));
 
-notrace static void do_coarse(clockid_t clk, struct timespec *ts)
+int __vdso_clock_getres(clockid_t clock,
+			struct __kernel_timespec *res)
 {
-	struct vgtod_ts *base = &gtod->basetime[clk];
-	unsigned int seq;
-
-	do {
-		seq = gtod_read_begin(gtod);
-		ts->tv_sec = base->sec;
-		ts->tv_nsec = base->nsec;
-	} while (unlikely(gtod_read_retry(gtod, seq)));
+	return __cvdso_clock_getres(clock, res);
 }
+int clock_getres(clockid_t, struct __kernel_timespec *)
+	__attribute__((weak, alias("__vdso_clock_getres")));
 
-notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
+#else
+/* i386 only */
+extern int __vdso_clock_gettime(clockid_t clock, struct old_timespec32 *ts);
+extern int __vdso_clock_getres(clockid_t clock, struct old_timespec32 *res);
+
+int __vdso_clock_gettime(clockid_t clock, struct old_timespec32 *ts)
 {
-	unsigned int msk;
-
-	/* Sort out negative (CPU/FD) and invalid clocks */
-	if (unlikely((unsigned int) clock >= MAX_CLOCKS))
-		return vdso_fallback_gettime(clock, ts);
-
-	/*
-	 * Convert the clockid to a bitmask and use it to check which
-	 * clocks are handled in the VDSO directly.
-	 */
-	msk = 1U << clock;
-	if (likely(msk & VGTOD_HRES)) {
-		return do_hres(clock, ts);
-	} else if (msk & VGTOD_COARSE) {
-		do_coarse(clock, ts);
-		return 0;
-	}
-	return vdso_fallback_gettime(clock, ts);
+	return __cvdso_clock_gettime32(clock, ts);
 }
 
-int clock_gettime(clockid_t, struct timespec *)
+int clock_gettime(clockid_t, struct old_timespec32 *)
 	__attribute__((weak, alias("__vdso_clock_gettime")));
 
-notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
+int __vdso_clock_gettime64(clockid_t clock, struct __kernel_timespec *ts)
 {
-	if (likely(tv != NULL)) {
-		struct timespec *ts = (struct timespec *) tv;
-
-		do_hres(CLOCK_REALTIME, ts);
-		tv->tv_usec /= 1000;
-	}
-	if (unlikely(tz != NULL)) {
-		tz->tz_minuteswest = gtod->tz_minuteswest;
-		tz->tz_dsttime = gtod->tz_dsttime;
-	}
-
-	return 0;
+	return __cvdso_clock_gettime(clock, ts);
 }
-int gettimeofday(struct timeval *, struct timezone *)
-	__attribute__((weak, alias("__vdso_gettimeofday")));
 
-/*
- * This will break when the xtime seconds get inaccurate, but that is
- * unlikely
- */
-notrace time_t __vdso_time(time_t *t)
-{
-	/* This is atomic on x86 so we don't need any locks. */
-	time_t result = READ_ONCE(gtod->basetime[CLOCK_REALTIME].sec);
+int clock_gettime64(clockid_t, struct __kernel_timespec *)
+	__attribute__((weak, alias("__vdso_clock_gettime64")));
 
-	if (t)
-		*t = result;
-	return result;
+int __vdso_clock_getres(clockid_t clock, struct old_timespec32 *res)
+{
+	return __cvdso_clock_getres_time32(clock, res);
 }
-time_t time(time_t *t)
-	__attribute__((weak, alias("__vdso_time")));
+
+int clock_getres(clockid_t, struct old_timespec32 *)
+	__attribute__((weak, alias("__vdso_clock_getres")));
+#endif
diff --git a/arch/x86/entry/vdso/vdso.lds.S b/arch/x86/entry/vdso/vdso.lds.S
index d3a2dce4cfa9..36b644e16272 100644
--- a/arch/x86/entry/vdso/vdso.lds.S
+++ b/arch/x86/entry/vdso/vdso.lds.S
@@ -25,6 +25,8 @@ VERSION {
 		__vdso_getcpu;
 		time;
 		__vdso_time;
+		clock_getres;
+		__vdso_clock_getres;
 	local: *;
 	};
 }
diff --git a/arch/x86/entry/vdso/vdso32/vdso32.lds.S b/arch/x86/entry/vdso/vdso32/vdso32.lds.S
index 422764a81d32..c7720995ab1a 100644
--- a/arch/x86/entry/vdso/vdso32/vdso32.lds.S
+++ b/arch/x86/entry/vdso/vdso32/vdso32.lds.S
@@ -26,6 +26,8 @@ VERSION
 		__vdso_clock_gettime;
 		__vdso_gettimeofday;
 		__vdso_time;
+		__vdso_clock_getres;
+		__vdso_clock_gettime64;
 	};
 
 	LINUX_2.5 {
diff --git a/arch/x86/entry/vdso/vdsox32.lds.S b/arch/x86/entry/vdso/vdsox32.lds.S
index 05cd1c5c4a15..16a8050a4fb6 100644
--- a/arch/x86/entry/vdso/vdsox32.lds.S
+++ b/arch/x86/entry/vdso/vdsox32.lds.S
@@ -21,6 +21,7 @@ VERSION {
 		__vdso_gettimeofday;
 		__vdso_getcpu;
 		__vdso_time;
+		__vdso_clock_getres;
 	local: *;
 	};
 }
diff --git a/arch/x86/entry/vdso/vgetcpu.c b/arch/x86/entry/vdso/vgetcpu.c
index f86ab0ae1777..b88a82bbc359 100644
--- a/arch/x86/entry/vdso/vgetcpu.c
+++ b/arch/x86/entry/vdso/vgetcpu.c
@@ -1,6 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright 2006 Andi Kleen, SUSE Labs.
- * Subject to the GNU Public License, v.2
  *
  * Fast user context implementation of getcpu()
  */
diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index babc4e7a519c..349a61d8bf34 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -1,6 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright 2007 Andi Kleen, SUSE Labs.
- * Subject to the GPL, v.2
  *
  * This contains most of the x86 vDSO kernel-side code.
  */
@@ -22,7 +22,7 @@
 #include <asm/page.h>
 #include <asm/desc.h>
 #include <asm/cpufeature.h>
-#include <asm/mshyperv.h>
+#include <clocksource/hyperv_timer.h>
 
 #if defined(CONFIG_X86_64)
 unsigned int __read_mostly vdso64_enabled = 1;
diff --git a/arch/x86/entry/vsyscall/Makefile b/arch/x86/entry/vsyscall/Makefile
index a9f4856f622a..93c1b3e949a7 100644
--- a/arch/x86/entry/vsyscall/Makefile
+++ b/arch/x86/entry/vsyscall/Makefile
@@ -1,7 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
 # Makefile for the x86 low level vsyscall code
 #
-obj-y					:= vsyscall_gtod.o
-
 obj-$(CONFIG_X86_VSYSCALL_EMULATION)	+= vsyscall_64.o vsyscall_emu_64.o
 
diff --git a/arch/x86/entry/vsyscall/vsyscall_64.c b/arch/x86/entry/vsyscall/vsyscall_64.c
index d9d81ad7a400..07003f3f1bfc 100644
--- a/arch/x86/entry/vsyscall/vsyscall_64.c
+++ b/arch/x86/entry/vsyscall/vsyscall_64.c
@@ -42,9 +42,11 @@
 #define CREATE_TRACE_POINTS
 #include "vsyscall_trace.h"
 
-static enum { EMULATE, NONE } vsyscall_mode =
+static enum { EMULATE, XONLY, NONE } vsyscall_mode __ro_after_init =
 #ifdef CONFIG_LEGACY_VSYSCALL_NONE
 	NONE;
+#elif defined(CONFIG_LEGACY_VSYSCALL_XONLY)
+	XONLY;
 #else
 	EMULATE;
 #endif
@@ -54,6 +56,8 @@ static int __init vsyscall_setup(char *str)
 	if (str) {
 		if (!strcmp("emulate", str))
 			vsyscall_mode = EMULATE;
+		else if (!strcmp("xonly", str))
+			vsyscall_mode = XONLY;
 		else if (!strcmp("none", str))
 			vsyscall_mode = NONE;
 		else
@@ -113,7 +117,8 @@ static bool write_ok_or_segv(unsigned long ptr, size_t size)
 	}
 }
 
-bool emulate_vsyscall(struct pt_regs *regs, unsigned long address)
+bool emulate_vsyscall(unsigned long error_code,
+		      struct pt_regs *regs, unsigned long address)
 {
 	struct task_struct *tsk;
 	unsigned long caller;
@@ -122,6 +127,22 @@ bool emulate_vsyscall(struct pt_regs *regs, unsigned long address)
 	long ret;
 	unsigned long orig_dx;
 
+	/* Write faults or kernel-privilege faults never get fixed up. */
+	if ((error_code & (X86_PF_WRITE | X86_PF_USER)) != X86_PF_USER)
+		return false;
+
+	if (!(error_code & X86_PF_INSTR)) {
+		/* Failed vsyscall read */
+		if (vsyscall_mode == EMULATE)
+			return false;
+
+		/*
+		 * User code tried and failed to read the vsyscall page.
+		 */
+		warn_bad_vsyscall(KERN_INFO, regs, "vsyscall read attempt denied -- look up the vsyscall kernel parameter if you need a workaround");
+		return false;
+	}
+
 	/*
 	 * No point in checking CS -- the only way to get here is a user mode
 	 * trap to a high address, which means that we're in 64-bit user code.
@@ -284,7 +305,7 @@ static const char *gate_vma_name(struct vm_area_struct *vma)
 static const struct vm_operations_struct gate_vma_ops = {
 	.name = gate_vma_name,
 };
-static struct vm_area_struct gate_vma = {
+static struct vm_area_struct gate_vma __ro_after_init = {
 	.vm_start	= VSYSCALL_ADDR,
 	.vm_end		= VSYSCALL_ADDR + PAGE_SIZE,
 	.vm_page_prot	= PAGE_READONLY_EXEC,
@@ -357,12 +378,20 @@ void __init map_vsyscall(void)
 	extern char __vsyscall_page;
 	unsigned long physaddr_vsyscall = __pa_symbol(&__vsyscall_page);
 
-	if (vsyscall_mode != NONE) {
+	/*
+	 * For full emulation, the page needs to exist for real.  In
+	 * execute-only mode, there is no PTE at all backing the vsyscall
+	 * page.
+	 */
+	if (vsyscall_mode == EMULATE) {
 		__set_fixmap(VSYSCALL_PAGE, physaddr_vsyscall,
 			     PAGE_KERNEL_VVAR);
 		set_vsyscall_pgtable_user_bits(swapper_pg_dir);
 	}
 
+	if (vsyscall_mode == XONLY)
+		gate_vma.vm_flags = VM_EXEC;
+
 	BUILD_BUG_ON((unsigned long)__fix_to_virt(VSYSCALL_PAGE) !=
 		     (unsigned long)VSYSCALL_ADDR);
 }
diff --git a/arch/x86/entry/vsyscall/vsyscall_emu_64.S b/arch/x86/entry/vsyscall/vsyscall_emu_64.S
index c9596a9af159..2e203f3a25a7 100644
--- a/arch/x86/entry/vsyscall/vsyscall_emu_64.S
+++ b/arch/x86/entry/vsyscall/vsyscall_emu_64.S
@@ -1,9 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * vsyscall_emu_64.S: Vsyscall emulation page
  *
  * Copyright (c) 2011 Andy Lutomirski
- *
- * Subject to the GNU General Public License, version 2
  */
 
 #include <linux/linkage.h>
diff --git a/arch/x86/entry/vsyscall/vsyscall_gtod.c b/arch/x86/entry/vsyscall/vsyscall_gtod.c
deleted file mode 100644
index cfcdba082feb..000000000000
--- a/arch/x86/entry/vsyscall/vsyscall_gtod.c
+++ /dev/null
@@ -1,83 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- *  Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
- *  Copyright 2003 Andi Kleen, SuSE Labs.
- *
- *  Modified for x86 32 bit architecture by
- *  Stefani Seibold <stefani@seibold.net>
- *  sponsored by Rohde & Schwarz GmbH & Co. KG Munich/Germany
- *
- *  Thanks to hpa@transmeta.com for some useful hint.
- *  Special thanks to Ingo Molnar for his early experience with
- *  a different vsyscall implementation for Linux/IA32 and for the name.
- *
- */
-
-#include <linux/timekeeper_internal.h>
-#include <asm/vgtod.h>
-#include <asm/vvar.h>
-
-int vclocks_used __read_mostly;
-
-DEFINE_VVAR(struct vsyscall_gtod_data, vsyscall_gtod_data);
-
-void update_vsyscall_tz(void)
-{
-	vsyscall_gtod_data.tz_minuteswest = sys_tz.tz_minuteswest;
-	vsyscall_gtod_data.tz_dsttime = sys_tz.tz_dsttime;
-}
-
-void update_vsyscall(struct timekeeper *tk)
-{
-	int vclock_mode = tk->tkr_mono.clock->archdata.vclock_mode;
-	struct vsyscall_gtod_data *vdata = &vsyscall_gtod_data;
-	struct vgtod_ts *base;
-	u64 nsec;
-
-	/* Mark the new vclock used. */
-	BUILD_BUG_ON(VCLOCK_MAX >= 32);
-	WRITE_ONCE(vclocks_used, READ_ONCE(vclocks_used) | (1 << vclock_mode));
-
-	gtod_write_begin(vdata);
-
-	/* copy vsyscall data */
-	vdata->vclock_mode	= vclock_mode;
-	vdata->cycle_last	= tk->tkr_mono.cycle_last;
-	vdata->mask		= tk->tkr_mono.mask;
-	vdata->mult		= tk->tkr_mono.mult;
-	vdata->shift		= tk->tkr_mono.shift;
-
-	base = &vdata->basetime[CLOCK_REALTIME];
-	base->sec = tk->xtime_sec;
-	base->nsec = tk->tkr_mono.xtime_nsec;
-
-	base = &vdata->basetime[CLOCK_TAI];
-	base->sec = tk->xtime_sec + (s64)tk->tai_offset;
-	base->nsec = tk->tkr_mono.xtime_nsec;
-
-	base = &vdata->basetime[CLOCK_MONOTONIC];
-	base->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
-	nsec = tk->tkr_mono.xtime_nsec;
-	nsec +=	((u64)tk->wall_to_monotonic.tv_nsec << tk->tkr_mono.shift);
-	while (nsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) {
-		nsec -= ((u64)NSEC_PER_SEC) << tk->tkr_mono.shift;
-		base->sec++;
-	}
-	base->nsec = nsec;
-
-	base = &vdata->basetime[CLOCK_REALTIME_COARSE];
-	base->sec = tk->xtime_sec;
-	base->nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
-
-	base = &vdata->basetime[CLOCK_MONOTONIC_COARSE];
-	base->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec;
-	nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
-	nsec += tk->wall_to_monotonic.tv_nsec;
-	while (nsec >= NSEC_PER_SEC) {
-		nsec -= NSEC_PER_SEC;
-		base->sec++;
-	}
-	base->nsec = nsec;
-
-	gtod_write_end(vdata);
-}