v4.19.13 snapshot.
diff --git a/arch/x86/um/asm/apic.h b/arch/x86/um/asm/apic.h
new file mode 100644
index 0000000..876dee8
--- /dev/null
+++ b/arch/x86/um/asm/apic.h
@@ -0,0 +1,4 @@
+#ifndef __UM_APIC_H
+#define __UM_APIC_H
+
+#endif
diff --git a/arch/x86/um/asm/arch_hweight.h b/arch/x86/um/asm/arch_hweight.h
new file mode 100644
index 0000000..0d2d5fb
--- /dev/null
+++ b/arch/x86/um/asm/arch_hweight.h
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_UM_HWEIGHT_H
+#define _ASM_UM_HWEIGHT_H
+
+#include <asm-generic/bitops/arch_hweight.h>
+
+#endif
diff --git a/arch/x86/um/asm/archparam.h b/arch/x86/um/asm/archparam.h
new file mode 100644
index 0000000..c17cf68
--- /dev/null
+++ b/arch/x86/um/asm/archparam.h
@@ -0,0 +1,20 @@
+/* 
+ * Copyright (C) 2000 - 2003 Jeff Dike (jdike@addtoit.com)
+ * Copyright 2003 PathScale, Inc.
+ * Licensed under the GPL
+ */
+
+#ifndef __UM_ARCHPARAM_H
+#define __UM_ARCHPARAM_H
+
+#ifdef CONFIG_X86_32
+
+#ifdef CONFIG_X86_PAE
+#define LAST_PKMAP 512
+#else
+#define LAST_PKMAP 1024
+#endif
+
+#endif
+
+#endif
diff --git a/arch/x86/um/asm/barrier.h b/arch/x86/um/asm/barrier.h
new file mode 100644
index 0000000..f31e5d9
--- /dev/null
+++ b/arch/x86/um/asm/barrier.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_UM_BARRIER_H_
+#define _ASM_UM_BARRIER_H_
+
+#include <asm/asm.h>
+#include <asm/segment.h>
+#include <asm/cpufeatures.h>
+#include <asm/cmpxchg.h>
+#include <asm/nops.h>
+
+#include <linux/kernel.h>
+#include <linux/irqflags.h>
+
+/*
+ * Force strict CPU ordering.
+ * And yes, this is required on UP too when we're talking
+ * to devices.
+ */
+#ifdef CONFIG_X86_32
+
+#define mb()	alternative("lock; addl $0,0(%%esp)", "mfence", X86_FEATURE_XMM2)
+#define rmb()	alternative("lock; addl $0,0(%%esp)", "lfence", X86_FEATURE_XMM2)
+#define wmb()	alternative("lock; addl $0,0(%%esp)", "sfence", X86_FEATURE_XMM)
+
+#else /* CONFIG_X86_32 */
+
+#define mb()	asm volatile("mfence" : : : "memory")
+#define rmb()	asm volatile("lfence" : : : "memory")
+#define wmb()	asm volatile("sfence" : : : "memory")
+
+#endif /* CONFIG_X86_32 */
+
+#define dma_rmb()	barrier()
+#define dma_wmb()	barrier()
+
+#include <asm-generic/barrier.h>
+
+#endif
diff --git a/arch/x86/um/asm/checksum.h b/arch/x86/um/asm/checksum.h
new file mode 100644
index 0000000..2a56cac
--- /dev/null
+++ b/arch/x86/um/asm/checksum.h
@@ -0,0 +1,155 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __UM_CHECKSUM_H
+#define __UM_CHECKSUM_H
+
+#include <linux/string.h>
+#include <linux/in6.h>
+#include <linux/uaccess.h>
+
+/*
+ * computes the checksum of a memory block at buff, length len,
+ * and adds in "sum" (32-bit)
+ *
+ * returns a 32-bit number suitable for feeding into itself
+ * or csum_tcpudp_magic
+ *
+ * this function must be called with even lengths, except
+ * for the last fragment, which may be odd
+ *
+ * it's best to have buff aligned on a 32-bit boundary
+ */
+extern __wsum csum_partial(const void *buff, int len, __wsum sum);
+
+/*
+ *	Note: when you get a NULL pointer exception here this means someone
+ *	passed in an incorrect kernel address to one of these functions.
+ *
+ *	If you use these functions directly please don't forget the
+ *	access_ok().
+ */
+
+static __inline__
+__wsum csum_partial_copy_nocheck(const void *src, void *dst,
+				       int len, __wsum sum)
+{
+	memcpy(dst, src, len);
+	return csum_partial(dst, len, sum);
+}
+
+/*
+ * the same as csum_partial, but copies from src while it
+ * checksums, and handles user-space pointer exceptions correctly, when needed.
+ *
+ * here even more important to align src and dst on a 32-bit (or even
+ * better 64-bit) boundary
+ */
+
+static __inline__
+__wsum csum_partial_copy_from_user(const void __user *src, void *dst,
+					 int len, __wsum sum, int *err_ptr)
+{
+	if (copy_from_user(dst, src, len)) {
+		*err_ptr = -EFAULT;
+		return (__force __wsum)-1;
+	}
+
+	return csum_partial(dst, len, sum);
+}
+
+/**
+ * csum_fold - Fold and invert a 32bit checksum.
+ * sum: 32bit unfolded sum
+ *
+ * Fold a 32bit running checksum to 16bit and invert it. This is usually
+ * the last step before putting a checksum into a packet.
+ * Make sure not to mix with 64bit checksums.
+ */
+static inline __sum16 csum_fold(__wsum sum)
+{
+	__asm__(
+		"  addl %1,%0\n"
+		"  adcl $0xffff,%0"
+		: "=r" (sum)
+		: "r" ((__force u32)sum << 16),
+		  "0" ((__force u32)sum & 0xffff0000)
+	);
+	return (__force __sum16)(~(__force u32)sum >> 16);
+}
+
+/**
+ * csum_tcpup_nofold - Compute an IPv4 pseudo header checksum.
+ * @saddr: source address
+ * @daddr: destination address
+ * @len: length of packet
+ * @proto: ip protocol of packet
+ * @sum: initial sum to be added in (32bit unfolded)
+ *
+ * Returns the pseudo header checksum the input data. Result is
+ * 32bit unfolded.
+ */
+static inline __wsum
+csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
+		  __u8 proto, __wsum sum)
+{
+	asm("  addl %1, %0\n"
+	    "  adcl %2, %0\n"
+	    "  adcl %3, %0\n"
+	    "  adcl $0, %0\n"
+		: "=r" (sum)
+	    : "g" (daddr), "g" (saddr), "g" ((len + proto) << 8), "0" (sum));
+	return sum;
+}
+
+/*
+ * computes the checksum of the TCP/UDP pseudo-header
+ * returns a 16-bit checksum, already complemented
+ */
+static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
+					__u32 len, __u8 proto,
+					__wsum sum)
+{
+	return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
+}
+
+/**
+ * ip_fast_csum - Compute the IPv4 header checksum efficiently.
+ * iph: ipv4 header
+ * ihl: length of header / 4
+ */
+static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
+{
+	unsigned int sum;
+
+	asm(	"  movl (%1), %0\n"
+		"  subl $4, %2\n"
+		"  jbe 2f\n"
+		"  addl 4(%1), %0\n"
+		"  adcl 8(%1), %0\n"
+		"  adcl 12(%1), %0\n"
+		"1: adcl 16(%1), %0\n"
+		"  lea 4(%1), %1\n"
+		"  decl %2\n"
+		"  jne	1b\n"
+		"  adcl $0, %0\n"
+		"  movl %0, %2\n"
+		"  shrl $16, %0\n"
+		"  addw %w2, %w0\n"
+		"  adcl $0, %0\n"
+		"  notl %0\n"
+		"2:"
+	/* Since the input registers which are loaded with iph and ipl
+	   are modified, we must also specify them as outputs, or gcc
+	   will assume they contain their original values. */
+	: "=r" (sum), "=r" (iph), "=r" (ihl)
+	: "1" (iph), "2" (ihl)
+	: "memory");
+	return (__force __sum16)sum;
+}
+
+#ifdef CONFIG_X86_32
+# include "checksum_32.h"
+#else
+# include "checksum_64.h"
+#endif
+
+#endif
diff --git a/arch/x86/um/asm/checksum_32.h b/arch/x86/um/asm/checksum_32.h
new file mode 100644
index 0000000..83a75f8
--- /dev/null
+++ b/arch/x86/um/asm/checksum_32.h
@@ -0,0 +1,61 @@
+/*
+ * Licensed under the GPL
+ */
+
+#ifndef __UM_SYSDEP_CHECKSUM_H
+#define __UM_SYSDEP_CHECKSUM_H
+
+static inline __sum16 ip_compute_csum(const void *buff, int len)
+{
+    return csum_fold (csum_partial(buff, len, 0));
+}
+
+#define _HAVE_ARCH_IPV6_CSUM
+static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
+					  const struct in6_addr *daddr,
+					  __u32 len, __u8 proto,
+					  __wsum sum)
+{
+	__asm__(
+		"addl 0(%1), %0		;\n"
+		"adcl 4(%1), %0		;\n"
+		"adcl 8(%1), %0		;\n"
+		"adcl 12(%1), %0	;\n"
+		"adcl 0(%2), %0		;\n"
+		"adcl 4(%2), %0		;\n"
+		"adcl 8(%2), %0		;\n"
+		"adcl 12(%2), %0	;\n"
+		"adcl %3, %0		;\n"
+		"adcl %4, %0		;\n"
+		"adcl $0, %0		;\n"
+		: "=&r" (sum)
+		: "r" (saddr), "r" (daddr),
+		  "r"(htonl(len)), "r"(htonl(proto)), "0"(sum));
+
+	return csum_fold(sum);
+}
+
+/*
+ *	Copy and checksum to user
+ */
+#define HAVE_CSUM_COPY_USER
+static __inline__ __wsum csum_and_copy_to_user(const void *src,
+						     void __user *dst,
+						     int len, __wsum sum, int *err_ptr)
+{
+	if (access_ok(VERIFY_WRITE, dst, len)) {
+		if (copy_to_user(dst, src, len)) {
+			*err_ptr = -EFAULT;
+			return (__force __wsum)-1;
+		}
+
+		return csum_partial(src, len, sum);
+	}
+
+	if (len)
+		*err_ptr = -EFAULT;
+
+	return (__force __wsum)-1; /* invalid checksum */
+}
+
+#endif
diff --git a/arch/x86/um/asm/checksum_64.h b/arch/x86/um/asm/checksum_64.h
new file mode 100644
index 0000000..7b6cd19
--- /dev/null
+++ b/arch/x86/um/asm/checksum_64.h
@@ -0,0 +1,19 @@
+/*
+ * Licensed under the GPL
+ */
+
+#ifndef __UM_SYSDEP_CHECKSUM_H
+#define __UM_SYSDEP_CHECKSUM_H
+
+static inline unsigned add32_with_carry(unsigned a, unsigned b)
+{
+        asm("addl %2,%0\n\t"
+            "adcl $0,%0"
+            : "=r" (a)
+            : "0" (a), "r" (b));
+        return a;
+}
+
+extern __sum16 ip_compute_csum(const void *buff, int len);
+
+#endif
diff --git a/arch/x86/um/asm/desc.h b/arch/x86/um/asm/desc.h
new file mode 100644
index 0000000..34de4e9
--- /dev/null
+++ b/arch/x86/um/asm/desc.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __UM_DESC_H
+#define __UM_DESC_H
+
+/* Taken from asm-i386/desc.h, it's the only thing we need. The rest wouldn't
+ * compile, and has never been used. */
+#define LDT_empty(info) (\
+	(info)->base_addr	== 0	&& \
+	(info)->limit		== 0	&& \
+	(info)->contents	== 0	&& \
+	(info)->read_exec_only	== 1	&& \
+	(info)->seg_32bit	== 0	&& \
+	(info)->limit_in_pages	== 0	&& \
+	(info)->seg_not_present	== 1	&& \
+	(info)->useable		== 0	)
+
+#endif
diff --git a/arch/x86/um/asm/elf.h b/arch/x86/um/asm/elf.h
new file mode 100644
index 0000000..5481972
--- /dev/null
+++ b/arch/x86/um/asm/elf.h
@@ -0,0 +1,218 @@
+/*
+ * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ * Licensed under the GPL
+ */
+#ifndef __UM_ELF_X86_H
+#define __UM_ELF_X86_H
+
+#include <asm/user.h>
+#include <skas.h>
+
+#ifdef CONFIG_X86_32
+
+#define R_386_NONE	0
+#define R_386_32	1
+#define R_386_PC32	2
+#define R_386_GOT32	3
+#define R_386_PLT32	4
+#define R_386_COPY	5
+#define R_386_GLOB_DAT	6
+#define R_386_JMP_SLOT	7
+#define R_386_RELATIVE	8
+#define R_386_GOTOFF	9
+#define R_386_GOTPC	10
+#define R_386_NUM	11
+
+/*
+ * This is used to ensure we don't load something for the wrong architecture.
+ */
+#define elf_check_arch(x) \
+	(((x)->e_machine == EM_386) || ((x)->e_machine == EM_486))
+
+#define ELF_CLASS	ELFCLASS32
+#define ELF_DATA        ELFDATA2LSB
+#define ELF_ARCH        EM_386
+
+#define ELF_PLAT_INIT(regs, load_addr) do { \
+	PT_REGS_BX(regs) = 0; \
+	PT_REGS_CX(regs) = 0; \
+	PT_REGS_DX(regs) = 0; \
+	PT_REGS_SI(regs) = 0; \
+	PT_REGS_DI(regs) = 0; \
+	PT_REGS_BP(regs) = 0; \
+	PT_REGS_AX(regs) = 0; \
+} while (0)
+
+/* Shamelessly stolen from include/asm-i386/elf.h */
+
+#define ELF_CORE_COPY_REGS(pr_reg, regs) do {	\
+	pr_reg[0] = PT_REGS_BX(regs);		\
+	pr_reg[1] = PT_REGS_CX(regs);		\
+	pr_reg[2] = PT_REGS_DX(regs);		\
+	pr_reg[3] = PT_REGS_SI(regs);		\
+	pr_reg[4] = PT_REGS_DI(regs);		\
+	pr_reg[5] = PT_REGS_BP(regs);		\
+	pr_reg[6] = PT_REGS_AX(regs);		\
+	pr_reg[7] = PT_REGS_DS(regs);		\
+	pr_reg[8] = PT_REGS_ES(regs);		\
+	/* fake once used fs and gs selectors? */	\
+	pr_reg[9] = PT_REGS_DS(regs);		\
+	pr_reg[10] = PT_REGS_DS(regs);		\
+	pr_reg[11] = PT_REGS_SYSCALL_NR(regs);	\
+	pr_reg[12] = PT_REGS_IP(regs);		\
+	pr_reg[13] = PT_REGS_CS(regs);		\
+	pr_reg[14] = PT_REGS_EFLAGS(regs);	\
+	pr_reg[15] = PT_REGS_SP(regs);		\
+	pr_reg[16] = PT_REGS_SS(regs);		\
+} while (0);
+
+extern char * elf_aux_platform;
+#define ELF_PLATFORM (elf_aux_platform)
+
+extern unsigned long vsyscall_ehdr;
+extern unsigned long vsyscall_end;
+extern unsigned long __kernel_vsyscall;
+
+/*
+ * This is the range that is readable by user mode, and things
+ * acting like user mode such as get_user_pages.
+ */
+#define FIXADDR_USER_START      vsyscall_ehdr
+#define FIXADDR_USER_END        vsyscall_end
+
+
+/*
+ * Architecture-neutral AT_ values in 0-17, leave some room
+ * for more of them, start the x86-specific ones at 32.
+ */
+#define AT_SYSINFO		32
+#define AT_SYSINFO_EHDR		33
+
+#define ARCH_DLINFO						\
+do {								\
+	if ( vsyscall_ehdr ) {					\
+		NEW_AUX_ENT(AT_SYSINFO,	__kernel_vsyscall);	\
+		NEW_AUX_ENT(AT_SYSINFO_EHDR, vsyscall_ehdr);	\
+	}							\
+} while (0)
+
+#else
+
+/* x86-64 relocation types, taken from asm-x86_64/elf.h */
+#define R_X86_64_NONE		0	/* No reloc */
+#define R_X86_64_64		1	/* Direct 64 bit  */
+#define R_X86_64_PC32		2	/* PC relative 32 bit signed */
+#define R_X86_64_GOT32		3	/* 32 bit GOT entry */
+#define R_X86_64_PLT32		4	/* 32 bit PLT address */
+#define R_X86_64_COPY		5	/* Copy symbol at runtime */
+#define R_X86_64_GLOB_DAT	6	/* Create GOT entry */
+#define R_X86_64_JUMP_SLOT	7	/* Create PLT entry */
+#define R_X86_64_RELATIVE	8	/* Adjust by program base */
+#define R_X86_64_GOTPCREL	9	/* 32 bit signed pc relative
+					   offset to GOT */
+#define R_X86_64_32		10	/* Direct 32 bit zero extended */
+#define R_X86_64_32S		11	/* Direct 32 bit sign extended */
+#define R_X86_64_16		12	/* Direct 16 bit zero extended */
+#define R_X86_64_PC16		13	/* 16 bit sign extended pc relative */
+#define R_X86_64_8		14	/* Direct 8 bit sign extended  */
+#define R_X86_64_PC8		15	/* 8 bit sign extended pc relative */
+
+#define R_X86_64_NUM		16
+
+/*
+ * This is used to ensure we don't load something for the wrong architecture.
+ */
+#define elf_check_arch(x) \
+	((x)->e_machine == EM_X86_64)
+
+#define ELF_CLASS	ELFCLASS64
+#define ELF_DATA        ELFDATA2LSB
+#define ELF_ARCH        EM_X86_64
+
+#define ELF_PLAT_INIT(regs, load_addr)    do { \
+	PT_REGS_BX(regs) = 0; \
+	PT_REGS_CX(regs) = 0; \
+	PT_REGS_DX(regs) = 0; \
+	PT_REGS_SI(regs) = 0; \
+	PT_REGS_DI(regs) = 0; \
+	PT_REGS_BP(regs) = 0; \
+	PT_REGS_AX(regs) = 0; \
+	PT_REGS_R8(regs) = 0; \
+	PT_REGS_R9(regs) = 0; \
+	PT_REGS_R10(regs) = 0; \
+	PT_REGS_R11(regs) = 0; \
+	PT_REGS_R12(regs) = 0; \
+	PT_REGS_R13(regs) = 0; \
+	PT_REGS_R14(regs) = 0; \
+	PT_REGS_R15(regs) = 0; \
+} while (0)
+
+#define ELF_CORE_COPY_REGS(pr_reg, _regs)		\
+	(pr_reg)[0] = (_regs)->regs.gp[0];			\
+	(pr_reg)[1] = (_regs)->regs.gp[1];			\
+	(pr_reg)[2] = (_regs)->regs.gp[2];			\
+	(pr_reg)[3] = (_regs)->regs.gp[3];			\
+	(pr_reg)[4] = (_regs)->regs.gp[4];			\
+	(pr_reg)[5] = (_regs)->regs.gp[5];			\
+	(pr_reg)[6] = (_regs)->regs.gp[6];			\
+	(pr_reg)[7] = (_regs)->regs.gp[7];			\
+	(pr_reg)[8] = (_regs)->regs.gp[8];			\
+	(pr_reg)[9] = (_regs)->regs.gp[9];			\
+	(pr_reg)[10] = (_regs)->regs.gp[10];			\
+	(pr_reg)[11] = (_regs)->regs.gp[11];			\
+	(pr_reg)[12] = (_regs)->regs.gp[12];			\
+	(pr_reg)[13] = (_regs)->regs.gp[13];			\
+	(pr_reg)[14] = (_regs)->regs.gp[14];			\
+	(pr_reg)[15] = (_regs)->regs.gp[15];			\
+	(pr_reg)[16] = (_regs)->regs.gp[16];			\
+	(pr_reg)[17] = (_regs)->regs.gp[17];			\
+	(pr_reg)[18] = (_regs)->regs.gp[18];			\
+	(pr_reg)[19] = (_regs)->regs.gp[19];			\
+	(pr_reg)[20] = (_regs)->regs.gp[20];			\
+	(pr_reg)[21] = current->thread.arch.fs;			\
+	(pr_reg)[22] = 0;					\
+	(pr_reg)[23] = 0;					\
+	(pr_reg)[24] = 0;					\
+	(pr_reg)[25] = 0;					\
+	(pr_reg)[26] = 0;
+
+#define ELF_PLATFORM "x86_64"
+
+/* No user-accessible fixmap addresses, i.e. vsyscall */
+#define FIXADDR_USER_START      0
+#define FIXADDR_USER_END        0
+
+#define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1
+struct linux_binprm;
+extern int arch_setup_additional_pages(struct linux_binprm *bprm,
+	int uses_interp);
+
+extern unsigned long um_vdso_addr;
+#define AT_SYSINFO_EHDR 33
+#define ARCH_DLINFO	NEW_AUX_ENT(AT_SYSINFO_EHDR, um_vdso_addr)
+
+#endif
+
+typedef unsigned long elf_greg_t;
+
+#define ELF_NGREG (sizeof (struct user_regs_struct) / sizeof(elf_greg_t))
+typedef elf_greg_t elf_gregset_t[ELF_NGREG];
+
+typedef struct user_i387_struct elf_fpregset_t;
+
+struct task_struct;
+
+extern int elf_core_copy_fpregs(struct task_struct *t, elf_fpregset_t *fpu);
+
+#define ELF_CORE_COPY_FPREGS(t, fpu) elf_core_copy_fpregs(t, fpu)
+
+#define ELF_EXEC_PAGESIZE 4096
+
+#define ELF_ET_DYN_BASE (TASK_SIZE / 3 * 2)
+
+extern long elf_aux_hwcap;
+#define ELF_HWCAP (elf_aux_hwcap)
+
+#define SET_PERSONALITY(ex) do ; while(0)
+
+#endif
diff --git a/arch/x86/um/asm/irq_vectors.h b/arch/x86/um/asm/irq_vectors.h
new file mode 100644
index 0000000..272a81e
--- /dev/null
+++ b/arch/x86/um/asm/irq_vectors.h
@@ -0,0 +1,10 @@
+/* 
+ * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
+ * Licensed under the GPL
+ */
+
+#ifndef __UM_IRQ_VECTORS_H
+#define __UM_IRQ_VECTORS_H
+
+#endif
+
diff --git a/arch/x86/um/asm/mm_context.h b/arch/x86/um/asm/mm_context.h
new file mode 100644
index 0000000..4a73d63
--- /dev/null
+++ b/arch/x86/um/asm/mm_context.h
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2004 Fujitsu Siemens Computers GmbH
+ * Licensed under the GPL
+ *
+ * Author: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
+ */
+
+#ifndef __ASM_LDT_H
+#define __ASM_LDT_H
+
+#include <linux/mutex.h>
+#include <asm/ldt.h>
+
+extern void ldt_host_info(void);
+
+#define LDT_PAGES_MAX \
+	((LDT_ENTRIES * LDT_ENTRY_SIZE)/PAGE_SIZE)
+#define LDT_ENTRIES_PER_PAGE \
+	(PAGE_SIZE/LDT_ENTRY_SIZE)
+#define LDT_DIRECT_ENTRIES \
+	((LDT_PAGES_MAX*sizeof(void *))/LDT_ENTRY_SIZE)
+
+struct ldt_entry {
+	__u32 a;
+	__u32 b;
+};
+
+typedef struct uml_ldt {
+	int entry_count;
+	struct mutex lock;
+	union {
+		struct ldt_entry * pages[LDT_PAGES_MAX];
+		struct ldt_entry entries[LDT_DIRECT_ENTRIES];
+	} u;
+} uml_ldt_t;
+
+#define LDT_entry_a(info) \
+	((((info)->base_addr & 0x0000ffff) << 16) | ((info)->limit & 0x0ffff))
+
+#define LDT_entry_b(info) \
+	(((info)->base_addr & 0xff000000) | \
+	(((info)->base_addr & 0x00ff0000) >> 16) | \
+	((info)->limit & 0xf0000) | \
+	(((info)->read_exec_only ^ 1) << 9) | \
+	((info)->contents << 10) | \
+	(((info)->seg_not_present ^ 1) << 15) | \
+	((info)->seg_32bit << 22) | \
+	((info)->limit_in_pages << 23) | \
+	((info)->useable << 20) | \
+	0x7000)
+
+#define _LDT_empty(info) (\
+	(info)->base_addr	== 0	&& \
+	(info)->limit		== 0	&& \
+	(info)->contents	== 0	&& \
+	(info)->read_exec_only	== 1	&& \
+	(info)->seg_32bit	== 0	&& \
+	(info)->limit_in_pages	== 0	&& \
+	(info)->seg_not_present	== 1	&& \
+	(info)->useable		== 0	)
+
+#ifdef CONFIG_X86_64
+#define LDT_empty(info) (_LDT_empty(info) && ((info)->lm == 0))
+#else
+#define LDT_empty(info) (_LDT_empty(info))
+#endif
+
+struct uml_arch_mm_context {
+	uml_ldt_t ldt;
+};
+
+#endif
diff --git a/arch/x86/um/asm/module.h b/arch/x86/um/asm/module.h
new file mode 100644
index 0000000..a3b061d
--- /dev/null
+++ b/arch/x86/um/asm/module.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __UM_MODULE_H
+#define __UM_MODULE_H
+
+/* UML is simple */
+struct mod_arch_specific
+{
+};
+
+#ifdef CONFIG_X86_32
+
+#define Elf_Shdr Elf32_Shdr
+#define Elf_Sym Elf32_Sym
+#define Elf_Ehdr Elf32_Ehdr
+
+#else
+
+#define Elf_Shdr Elf64_Shdr
+#define Elf_Sym Elf64_Sym
+#define Elf_Ehdr Elf64_Ehdr
+
+#endif
+
+#endif
diff --git a/arch/x86/um/asm/processor.h b/arch/x86/um/asm/processor.h
new file mode 100644
index 0000000..593d5f3
--- /dev/null
+++ b/arch/x86/um/asm/processor.h
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __UM_PROCESSOR_H
+#define __UM_PROCESSOR_H
+
+/* include faultinfo structure */
+#include <sysdep/faultinfo.h>
+
+#ifdef CONFIG_X86_32
+# include "processor_32.h"
+#else
+# include "processor_64.h"
+#endif
+
+#define KSTK_EIP(tsk) KSTK_REG(tsk, HOST_IP)
+#define KSTK_ESP(tsk) KSTK_REG(tsk, HOST_SP)
+#define KSTK_EBP(tsk) KSTK_REG(tsk, HOST_BP)
+
+#define ARCH_IS_STACKGROW(address) \
+       (address + 65536 + 32 * sizeof(unsigned long) >= UPT_SP(&current->thread.regs.regs))
+
+#include <asm/user.h>
+
+/* REP NOP (PAUSE) is a good thing to insert into busy-wait loops. */
+static inline void rep_nop(void)
+{
+	__asm__ __volatile__("rep;nop": : :"memory");
+}
+
+#define cpu_relax()		rep_nop()
+
+#define task_pt_regs(t) (&(t)->thread.regs)
+
+#include <asm/processor-generic.h>
+
+#endif
diff --git a/arch/x86/um/asm/processor_32.h b/arch/x86/um/asm/processor_32.h
new file mode 100644
index 0000000..c112de8
--- /dev/null
+++ b/arch/x86/um/asm/processor_32.h
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
+ * Licensed under the GPL
+ */
+
+#ifndef __UM_PROCESSOR_I386_H
+#define __UM_PROCESSOR_I386_H
+
+#include <linux/string.h>
+#include <asm/segment.h>
+#include <asm/ldt.h>
+
+extern int host_has_cmov;
+
+struct uml_tls_struct {
+	struct user_desc tls;
+	unsigned flushed:1;
+	unsigned present:1;
+};
+
+struct arch_thread {
+	struct uml_tls_struct tls_array[GDT_ENTRY_TLS_ENTRIES];
+	unsigned long debugregs[8];
+	int debugregs_seq;
+	struct faultinfo faultinfo;
+};
+
+#define INIT_ARCH_THREAD { \
+	.tls_array  		= { [ 0 ... GDT_ENTRY_TLS_ENTRIES - 1 ] = \
+				    { .present = 0, .flushed = 0 } }, \
+	.debugregs  		= { [ 0 ... 7 ] = 0 }, \
+	.debugregs_seq		= 0, \
+	.faultinfo		= { 0, 0, 0 } \
+}
+
+#define STACKSLOTS_PER_LINE 8
+
+static inline void arch_flush_thread(struct arch_thread *thread)
+{
+	/* Clear any TLS still hanging */
+	memset(&thread->tls_array, 0, sizeof(thread->tls_array));
+}
+
+static inline void arch_copy_thread(struct arch_thread *from,
+                                    struct arch_thread *to)
+{
+        memcpy(&to->tls_array, &from->tls_array, sizeof(from->tls_array));
+}
+
+/*
+ * Default implementation of macro that returns current
+ * instruction pointer ("program counter"). Stolen
+ * from asm-i386/processor.h
+ */
+#define current_text_addr() \
+	({ void *pc; __asm__("movl $1f,%0\n1:":"=g" (pc)); pc; })
+
+#define current_sp() ({ void *sp; __asm__("movl %%esp, %0" : "=r" (sp) : ); sp; })
+#define current_bp() ({ unsigned long bp; __asm__("movl %%ebp, %0" : "=r" (bp) : ); bp; })
+
+#endif
diff --git a/arch/x86/um/asm/processor_64.h b/arch/x86/um/asm/processor_64.h
new file mode 100644
index 0000000..c3be852
--- /dev/null
+++ b/arch/x86/um/asm/processor_64.h
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2003 PathScale, Inc.
+ *
+ * Licensed under the GPL
+ */
+
+#ifndef __UM_PROCESSOR_X86_64_H
+#define __UM_PROCESSOR_X86_64_H
+
+struct arch_thread {
+        unsigned long debugregs[8];
+        int debugregs_seq;
+        unsigned long fs;
+        struct faultinfo faultinfo;
+};
+
+#define INIT_ARCH_THREAD { .debugregs  		= { [ 0 ... 7 ] = 0 }, \
+			   .debugregs_seq	= 0, \
+			   .fs			= 0, \
+			   .faultinfo		= { 0, 0, 0 } }
+
+#define STACKSLOTS_PER_LINE 4
+
+static inline void arch_flush_thread(struct arch_thread *thread)
+{
+}
+
+static inline void arch_copy_thread(struct arch_thread *from,
+                                    struct arch_thread *to)
+{
+	to->fs = from->fs;
+}
+
+#define current_text_addr() \
+	({ void *pc; __asm__("movq $1f,%0\n1:":"=g" (pc)); pc; })
+
+#define current_sp() ({ void *sp; __asm__("movq %%rsp, %0" : "=r" (sp) : ); sp; })
+#define current_bp() ({ unsigned long bp; __asm__("movq %%rbp, %0" : "=r" (bp) : ); bp; })
+
+#endif
diff --git a/arch/x86/um/asm/ptrace.h b/arch/x86/um/asm/ptrace.h
new file mode 100644
index 0000000..83822fd
--- /dev/null
+++ b/arch/x86/um/asm/ptrace.h
@@ -0,0 +1,87 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __UM_X86_PTRACE_H
+#define __UM_X86_PTRACE_H
+
+#include <linux/compiler.h>
+#ifndef CONFIG_X86_32
+#define __FRAME_OFFSETS /* Needed to get the R* macros */
+#endif
+#include <asm/ptrace-generic.h>
+
+#define user_mode(r) UPT_IS_USER(&(r)->regs)
+
+#define PT_REGS_AX(r) UPT_AX(&(r)->regs)
+#define PT_REGS_BX(r) UPT_BX(&(r)->regs)
+#define PT_REGS_CX(r) UPT_CX(&(r)->regs)
+#define PT_REGS_DX(r) UPT_DX(&(r)->regs)
+
+#define PT_REGS_SI(r) UPT_SI(&(r)->regs)
+#define PT_REGS_DI(r) UPT_DI(&(r)->regs)
+#define PT_REGS_BP(r) UPT_BP(&(r)->regs)
+#define PT_REGS_EFLAGS(r) UPT_EFLAGS(&(r)->regs)
+
+#define PT_REGS_CS(r) UPT_CS(&(r)->regs)
+#define PT_REGS_SS(r) UPT_SS(&(r)->regs)
+#define PT_REGS_DS(r) UPT_DS(&(r)->regs)
+#define PT_REGS_ES(r) UPT_ES(&(r)->regs)
+
+#define PT_REGS_ORIG_SYSCALL(r) PT_REGS_AX(r)
+#define PT_REGS_SYSCALL_RET(r) PT_REGS_AX(r)
+
+#define PT_FIX_EXEC_STACK(sp) do ; while(0)
+
+#define profile_pc(regs) PT_REGS_IP(regs)
+
+#define UPT_RESTART_SYSCALL(r) (UPT_IP(r) -= 2)
+#define PT_REGS_SET_SYSCALL_RETURN(r, res) (PT_REGS_AX(r) = (res))
+
+static inline long regs_return_value(struct pt_regs *regs)
+{
+	return PT_REGS_AX(regs);
+}
+
+/*
+ * Forward declaration to avoid including sysdep/tls.h, which causes a
+ * circular include, and compilation failures.
+ */
+struct user_desc;
+
+#ifdef CONFIG_X86_32
+
+extern int ptrace_get_thread_area(struct task_struct *child, int idx,
+                                  struct user_desc __user *user_desc);
+
+extern int ptrace_set_thread_area(struct task_struct *child, int idx,
+                                  struct user_desc __user *user_desc);
+
+#else
+
+#define PT_REGS_R8(r) UPT_R8(&(r)->regs)
+#define PT_REGS_R9(r) UPT_R9(&(r)->regs)
+#define PT_REGS_R10(r) UPT_R10(&(r)->regs)
+#define PT_REGS_R11(r) UPT_R11(&(r)->regs)
+#define PT_REGS_R12(r) UPT_R12(&(r)->regs)
+#define PT_REGS_R13(r) UPT_R13(&(r)->regs)
+#define PT_REGS_R14(r) UPT_R14(&(r)->regs)
+#define PT_REGS_R15(r) UPT_R15(&(r)->regs)
+
+#include <asm/errno.h>
+
+static inline int ptrace_get_thread_area(struct task_struct *child, int idx,
+                                         struct user_desc __user *user_desc)
+{
+        return -ENOSYS;
+}
+
+static inline int ptrace_set_thread_area(struct task_struct *child, int idx,
+                                         struct user_desc __user *user_desc)
+{
+        return -ENOSYS;
+}
+
+extern long arch_prctl(struct task_struct *task, int option,
+		       unsigned long __user *addr);
+
+#endif
+#define user_stack_pointer(regs) PT_REGS_SP(regs)
+#endif /* __UM_X86_PTRACE_H */
diff --git a/arch/x86/um/asm/required-features.h b/arch/x86/um/asm/required-features.h
new file mode 100644
index 0000000..dfb967b
--- /dev/null
+++ b/arch/x86/um/asm/required-features.h
@@ -0,0 +1,9 @@
+#ifndef __UM_REQUIRED_FEATURES_H
+#define __UM_REQUIRED_FEATURES_H
+
+/*
+ * Nothing to see, just need something for the i386 and x86_64 asm
+ * headers to include.
+ */
+
+#endif
diff --git a/arch/x86/um/asm/segment.h b/arch/x86/um/asm/segment.h
new file mode 100644
index 0000000..453db37
--- /dev/null
+++ b/arch/x86/um/asm/segment.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __UM_SEGMENT_H
+#define __UM_SEGMENT_H
+
+extern int host_gdt_entry_tls_min;
+
+#define GDT_ENTRY_TLS_ENTRIES 3
+#define GDT_ENTRY_TLS_MIN host_gdt_entry_tls_min
+#define GDT_ENTRY_TLS_MAX (GDT_ENTRY_TLS_MIN + GDT_ENTRY_TLS_ENTRIES - 1)
+
+typedef struct {
+	unsigned long seg;
+} mm_segment_t;
+
+#define MAKE_MM_SEG(s)	((mm_segment_t) { (s) })
+#define KERNEL_DS	MAKE_MM_SEG(~0UL)
+#define USER_DS		MAKE_MM_SEG(TASK_SIZE)
+
+#endif
diff --git a/arch/x86/um/asm/syscall.h b/arch/x86/um/asm/syscall.h
new file mode 100644
index 0000000..ef898af
--- /dev/null
+++ b/arch/x86/um/asm/syscall.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __UM_ASM_SYSCALL_H
+#define __UM_ASM_SYSCALL_H
+
+#include <asm/syscall-generic.h>
+#include <uapi/linux/audit.h>
+
+typedef asmlinkage long (*sys_call_ptr_t)(unsigned long, unsigned long,
+					  unsigned long, unsigned long,
+					  unsigned long, unsigned long);
+
+static inline int syscall_get_arch(void)
+{
+#ifdef CONFIG_X86_32
+	return AUDIT_ARCH_I386;
+#else
+	return AUDIT_ARCH_X86_64;
+#endif
+}
+
+#endif /* __UM_ASM_SYSCALL_H */
diff --git a/arch/x86/um/asm/vm-flags.h b/arch/x86/um/asm/vm-flags.h
new file mode 100644
index 0000000..7c297e9
--- /dev/null
+++ b/arch/x86/um/asm/vm-flags.h
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2004 Jeff Dike (jdike@addtoit.com)
+ * Copyright 2003 PathScale, Inc.
+ * Licensed under the GPL
+ */
+
+#ifndef __VM_FLAGS_X86_H
+#define __VM_FLAGS_X86_H
+
+#ifdef CONFIG_X86_32
+
+#define VM_DATA_DEFAULT_FLAGS \
+	(VM_READ | VM_WRITE | \
+	((current->personality & READ_IMPLIES_EXEC) ? VM_EXEC : 0 ) | \
+		 VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
+
+#else
+
+#define VM_DATA_DEFAULT_FLAGS (VM_READ | VM_WRITE | VM_EXEC | \
+	VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
+#define VM_STACK_DEFAULT_FLAGS (VM_GROWSDOWN | VM_READ | VM_WRITE | \
+	VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
+
+#endif
+#endif