20 files changed, 437 insertions, 102 deletions

diff --git a/arch/x86/um/asm/archparam.h b/arch/x86/um/asm/archparam.h
deleted file mode 100644
index c17cf68dda0f..000000000000
--- a/arch/x86/um/asm/archparam.h
+++ /dev/null
@@ -1,20 +0,0 @@
-/* 
- * 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
index 4da336965698..b51aefd6ec2b 100644
--- a/arch/x86/um/asm/barrier.h
+++ b/arch/x86/um/asm/barrier.h
@@ -12,9 +12,9 @@
  */
 #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)
+#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 */
 
diff --git a/arch/x86/um/asm/checksum.h b/arch/x86/um/asm/checksum.h
index b07824500363..ddc144657efa 100644
--- a/arch/x86/um/asm/checksum.h
+++ b/arch/x86/um/asm/checksum.h
@@ -20,6 +20,9 @@
  */
 extern __wsum csum_partial(const void *buff, int len, __wsum sum);
 
+/* Do not call this directly. Declared for export type visibility. */
+extern __visible __wsum csum_partial_copy_generic(const void *src, void *dst, int len);
+
 /**
  * csum_fold - Fold and invert a 32bit checksum.
  * sum: 32bit unfolded sum
diff --git a/arch/x86/um/asm/module.h b/arch/x86/um/asm/module.h
deleted file mode 100644
index a3b061d66082..000000000000
--- a/arch/x86/um/asm/module.h
+++ /dev/null
@@ -1,24 +0,0 @@
-/* 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
index 478710384b34..e222d2ae28fd 100644
--- a/arch/x86/um/asm/processor.h
+++ b/arch/x86/um/asm/processor.h
@@ -21,10 +21,10 @@
 
 #include <asm/user.h>
 
-/* REP NOP (PAUSE) is a good thing to insert into busy-wait loops. */
-static __always_inline void rep_nop(void)
+/* PAUSE is a good thing to insert into busy-wait loops. */
+static __always_inline void native_pause(void)
 {
-	__asm__ __volatile__("rep;nop": : :"memory");
+	__asm__ __volatile__("pause": : :"memory");
 }
 
 static __always_inline void cpu_relax(void)
@@ -33,7 +33,7 @@ static __always_inline void cpu_relax(void)
 	    time_travel_mode == TT_MODE_EXTERNAL)
 		time_travel_ndelay(1);
 	else
-		rep_nop();
+		native_pause();
 }
 
 #define task_pt_regs(t) (&(t)->thread.regs)
diff --git a/arch/x86/um/os-Linux/mcontext.c b/arch/x86/um/os-Linux/mcontext.c
index e80ab7d28117..a21403df6663 100644
--- a/arch/x86/um/os-Linux/mcontext.c
+++ b/arch/x86/um/os-Linux/mcontext.c
@@ -1,9 +1,13 @@
 // SPDX-License-Identifier: GPL-2.0
-#include <sys/ucontext.h>
 #define __FRAME_OFFSETS
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <sys/ucontext.h>
 #include <asm/ptrace.h>
+#include <asm/sigcontext.h>
 #include <sysdep/ptrace.h>
 #include <sysdep/mcontext.h>
+#include <arch.h>
 
 void get_regs_from_mc(struct uml_pt_regs *regs, mcontext_t *mc)
 {
@@ -17,6 +21,10 @@ void get_regs_from_mc(struct uml_pt_regs *regs, mcontext_t *mc)
 	COPY2(UESP, ESP); /* sic */
 	COPY(EBX); COPY(EDX); COPY(ECX); COPY(EAX);
 	COPY(EIP); COPY_SEG_CPL3(CS); COPY(EFL); COPY_SEG_CPL3(SS);
+#undef COPY2
+#undef COPY
+#undef COPY_SEG
+#undef COPY_SEG_CPL3
 #else
 #define COPY2(X,Y) regs->gp[X/sizeof(unsigned long)] = mc->gregs[REG_##Y]
 #define COPY(X) regs->gp[X/sizeof(unsigned long)] = mc->gregs[REG_##X]
@@ -27,7 +35,226 @@ void get_regs_from_mc(struct uml_pt_regs *regs, mcontext_t *mc)
 	COPY(RIP);
 	COPY2(EFLAGS, EFL);
 	COPY2(CS, CSGSFS);
-	regs->gp[CS / sizeof(unsigned long)] &= 0xffff;
-	regs->gp[CS / sizeof(unsigned long)] |= 3;
+	regs->gp[SS / sizeof(unsigned long)] = mc->gregs[REG_CSGSFS] >> 48;
+#undef COPY2
+#undef COPY
+#endif
+}
+
+void mc_set_rip(void *_mc, void *target)
+{
+	mcontext_t *mc = _mc;
+
+#ifdef __i386__
+	mc->gregs[REG_EIP] = (unsigned long)target;
+#else
+	mc->gregs[REG_RIP] = (unsigned long)target;
 #endif
 }
+
+/* Same thing, but the copy macros are turned around. */
+void get_mc_from_regs(struct uml_pt_regs *regs, mcontext_t *mc, int single_stepping)
+{
+#ifdef __i386__
+#define COPY2(X,Y) mc->gregs[REG_##Y] = regs->gp[X]
+#define COPY(X) mc->gregs[REG_##X] = regs->gp[X]
+#define COPY_SEG(X) mc->gregs[REG_##X] = regs->gp[X] & 0xffff;
+#define COPY_SEG_CPL3(X) mc->gregs[REG_##X] = (regs->gp[X] & 0xffff) | 3;
+	COPY_SEG(GS); COPY_SEG(FS); COPY_SEG(ES); COPY_SEG(DS);
+	COPY(EDI); COPY(ESI); COPY(EBP);
+	COPY2(UESP, ESP); /* sic */
+	COPY(EBX); COPY(EDX); COPY(ECX); COPY(EAX);
+	COPY(EIP); COPY_SEG_CPL3(CS); COPY(EFL); COPY_SEG_CPL3(SS);
+#else
+#define COPY2(X,Y) mc->gregs[REG_##Y] = regs->gp[X/sizeof(unsigned long)]
+#define COPY(X) mc->gregs[REG_##X] = regs->gp[X/sizeof(unsigned long)]
+	COPY(R8); COPY(R9); COPY(R10); COPY(R11);
+	COPY(R12); COPY(R13); COPY(R14); COPY(R15);
+	COPY(RDI); COPY(RSI); COPY(RBP); COPY(RBX);
+	COPY(RDX); COPY(RAX); COPY(RCX); COPY(RSP);
+	COPY(RIP);
+	COPY2(EFLAGS, EFL);
+	mc->gregs[REG_CSGSFS] = mc->gregs[REG_CSGSFS] & 0xffffffffffffl;
+	mc->gregs[REG_CSGSFS] |= (regs->gp[SS / sizeof(unsigned long)] & 0xffff) << 48;
+#endif
+
+	if (single_stepping)
+		mc->gregs[REG_EFL] |= X86_EFLAGS_TF;
+	else
+		mc->gregs[REG_EFL] &= ~X86_EFLAGS_TF;
+}
+
+#ifdef CONFIG_X86_32
+struct _xstate_64 {
+	struct _fpstate_64		fpstate;
+	struct _header			xstate_hdr;
+	struct _ymmh_state		ymmh;
+	/* New processor state extensions go here: */
+};
+
+/* Not quite the right structures as these contain more information */
+int um_i387_from_fxsr(struct _fpstate_32 *i387,
+		      const struct _fpstate_64 *fxsave);
+int um_fxsr_from_i387(struct _fpstate_64 *fxsave,
+		      const struct _fpstate_32 *from);
+#else
+#define _xstate_64 _xstate
+#endif
+
+static struct _fpstate *get_fpstate(struct stub_data *data,
+				    mcontext_t *mcontext,
+				    int *fp_size)
+{
+	struct _fpstate *res;
+
+	/* Assume floating point registers are on the same page */
+	res = (void *)(((unsigned long)mcontext->fpregs &
+			(UM_KERN_PAGE_SIZE - 1)) +
+		       (unsigned long)&data->sigstack[0]);
+
+	if ((void *)res + sizeof(struct _fpstate) >
+	    (void *)data->sigstack + sizeof(data->sigstack))
+		return NULL;
+
+	if (res->sw_reserved.magic1 != FP_XSTATE_MAGIC1) {
+		*fp_size = sizeof(struct _fpstate);
+	} else {
+		char *magic2_addr;
+
+		magic2_addr = (void *)res;
+		magic2_addr += res->sw_reserved.extended_size;
+		magic2_addr -= FP_XSTATE_MAGIC2_SIZE;
+
+		/* We still need to be within our stack */
+		if ((void *)magic2_addr >
+		    (void *)data->sigstack + sizeof(data->sigstack))
+			return NULL;
+
+		/* If we do not read MAGIC2, then we did something wrong */
+		if (*(__u32 *)magic2_addr != FP_XSTATE_MAGIC2)
+			return NULL;
+
+		/* Remove MAGIC2 from the size, we do not save/restore it */
+		*fp_size = res->sw_reserved.extended_size -
+			   FP_XSTATE_MAGIC2_SIZE;
+	}
+
+	return res;
+}
+
+int get_stub_state(struct uml_pt_regs *regs, struct stub_data *data,
+		   unsigned long *fp_size_out)
+{
+	mcontext_t *mcontext;
+	struct _fpstate *fpstate_stub;
+	struct _xstate_64 *xstate_stub;
+	int fp_size, xstate_size;
+
+	/* mctx_offset is verified by wait_stub_done_seccomp */
+	mcontext = (void *)&data->sigstack[data->mctx_offset];
+
+	get_regs_from_mc(regs, mcontext);
+
+	fpstate_stub = get_fpstate(data, mcontext, &fp_size);
+	if (!fpstate_stub)
+		return -EINVAL;
+
+#ifdef CONFIG_X86_32
+	xstate_stub = (void *)&fpstate_stub->_fxsr_env;
+	xstate_size = fp_size - offsetof(struct _fpstate_32, _fxsr_env);
+#else
+	xstate_stub = (void *)fpstate_stub;
+	xstate_size = fp_size;
+#endif
+
+	if (fp_size_out)
+		*fp_size_out = xstate_size;
+
+	if (xstate_size > host_fp_size)
+		return -ENOSPC;
+
+	memcpy(&regs->fp, xstate_stub, xstate_size);
+
+	/* We do not need to read the x86_64 FS_BASE/GS_BASE registers as
+	 * we do not permit userspace to set them directly.
+	 */
+
+#ifdef CONFIG_X86_32
+	/* Read the i387 legacy FP registers */
+	if (um_fxsr_from_i387((void *)&regs->fp, fpstate_stub))
+		return -EINVAL;
+#endif
+
+	return 0;
+}
+
+/* Copied because we cannot include regset.h here. */
+struct task_struct;
+struct user_regset;
+struct membuf {
+	void *p;
+	size_t left;
+};
+
+int fpregs_legacy_get(struct task_struct *target,
+		      const struct user_regset *regset,
+		      struct membuf to);
+
+int set_stub_state(struct uml_pt_regs *regs, struct stub_data *data,
+		   int single_stepping)
+{
+	mcontext_t *mcontext;
+	struct _fpstate *fpstate_stub;
+	struct _xstate_64 *xstate_stub;
+	int fp_size, xstate_size;
+
+	/* mctx_offset is verified by wait_stub_done_seccomp */
+	mcontext = (void *)&data->sigstack[data->mctx_offset];
+
+	if ((unsigned long)mcontext < (unsigned long)data->sigstack ||
+	    (unsigned long)mcontext >
+			(unsigned long) data->sigstack +
+			sizeof(data->sigstack) - sizeof(*mcontext))
+		return -EINVAL;
+
+	get_mc_from_regs(regs, mcontext, single_stepping);
+
+	fpstate_stub = get_fpstate(data, mcontext, &fp_size);
+	if (!fpstate_stub)
+		return -EINVAL;
+
+#ifdef CONFIG_X86_32
+	xstate_stub = (void *)&fpstate_stub->_fxsr_env;
+	xstate_size = fp_size - offsetof(struct _fpstate_32, _fxsr_env);
+#else
+	xstate_stub = (void *)fpstate_stub;
+	xstate_size = fp_size;
+#endif
+
+	memcpy(xstate_stub, &regs->fp, xstate_size);
+
+#ifdef __i386__
+	/*
+	 * On x86, the GDT entries are updated by arch_set_tls.
+	 */
+
+	/* Store the i387 legacy FP registers which the host will use */
+	if (um_i387_from_fxsr(fpstate_stub, (void *)&regs->fp))
+		return -EINVAL;
+#else
+	/*
+	 * On x86_64, we need to sync the FS_BASE/GS_BASE registers using the
+	 * arch specific data.
+	 */
+	if (data->arch_data.fs_base != regs->gp[FS_BASE / sizeof(unsigned long)]) {
+		data->arch_data.fs_base = regs->gp[FS_BASE / sizeof(unsigned long)];
+		data->arch_data.sync |= STUB_SYNC_FS_BASE;
+	}
+	if (data->arch_data.gs_base != regs->gp[GS_BASE / sizeof(unsigned long)]) {
+		data->arch_data.gs_base = regs->gp[GS_BASE / sizeof(unsigned long)];
+		data->arch_data.sync |= STUB_SYNC_GS_BASE;
+	}
+#endif
+
+	return 0;
+}
diff --git a/arch/x86/um/os-Linux/registers.c b/arch/x86/um/os-Linux/registers.c
index 76eaeb93928c..eb1cdadc8a61 100644
--- a/arch/x86/um/os-Linux/registers.c
+++ b/arch/x86/um/os-Linux/registers.c
@@ -18,6 +18,7 @@
 #include <registers.h>
 #include <sys/mman.h>
 
+static unsigned long ptrace_regset;
 unsigned long host_fp_size;
 
 int get_fp_registers(int pid, unsigned long *regs)
@@ -27,7 +28,7 @@ int get_fp_registers(int pid, unsigned long *regs)
 		.iov_len = host_fp_size,
 	};
 
-	if (ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov) < 0)
+	if (ptrace(PTRACE_GETREGSET, pid, ptrace_regset, &iov) < 0)
 		return -errno;
 	return 0;
 }
@@ -39,7 +40,7 @@ int put_fp_registers(int pid, unsigned long *regs)
 		.iov_len = host_fp_size,
 	};
 
-	if (ptrace(PTRACE_SETREGSET, pid, NT_X86_XSTATE, &iov) < 0)
+	if (ptrace(PTRACE_SETREGSET, pid, ptrace_regset, &iov) < 0)
 		return -errno;
 	return 0;
 }
@@ -58,9 +59,23 @@ int arch_init_registers(int pid)
 		return -ENOMEM;
 
 	/* GDB has x86_xsave_length, which uses x86_cpuid_count */
-	ret = ptrace(PTRACE_GETREGSET, pid, NT_X86_XSTATE, &iov);
+	ptrace_regset = NT_X86_XSTATE;
+	ret = ptrace(PTRACE_GETREGSET, pid, ptrace_regset, &iov);
 	if (ret)
 		ret = -errno;
+
+	if (ret == -ENODEV) {
+#ifdef CONFIG_X86_32
+		ptrace_regset = NT_PRXFPREG;
+#else
+		ptrace_regset = NT_PRFPREG;
+#endif
+		iov.iov_len = 2 * 1024 * 1024;
+		ret = ptrace(PTRACE_GETREGSET, pid, ptrace_regset, &iov);
+		if (ret)
+			ret = -errno;
+	}
+
 	munmap(iov.iov_base, 2 * 1024 * 1024);
 
 	host_fp_size = iov.iov_len;
diff --git a/arch/x86/um/ptrace.c b/arch/x86/um/ptrace.c
index 57c504fd5626..fae8aabad10f 100644
--- a/arch/x86/um/ptrace.c
+++ b/arch/x86/um/ptrace.c
@@ -25,7 +25,8 @@ static inline unsigned short twd_i387_to_fxsr(unsigned short twd)
 	return tmp;
 }
 
-static inline unsigned long twd_fxsr_to_i387(struct user_fxsr_struct *fxsave)
+static inline unsigned long
+twd_fxsr_to_i387(const struct user_fxsr_struct *fxsave)
 {
 	struct _fpxreg *st = NULL;
 	unsigned long twd = (unsigned long) fxsave->twd;
@@ -69,12 +70,16 @@ static inline unsigned long twd_fxsr_to_i387(struct user_fxsr_struct *fxsave)
 	return ret;
 }
 
-/* Get/set the old 32bit i387 registers (pre-FPX) */
-static int fpregs_legacy_get(struct task_struct *target,
-			     const struct user_regset *regset,
-			     struct membuf to)
+/*
+ * Get/set the old 32bit i387 registers (pre-FPX)
+ *
+ * We provide simple wrappers for mcontext.c, they are only defined locally
+ * because mcontext.c is userspace facing and needs to a different definition
+ * of the structures.
+ */
+static int _um_i387_from_fxsr(struct membuf to,
+			      const struct user_fxsr_struct *fxsave)
 {
-	struct user_fxsr_struct *fxsave = (void *)target->thread.regs.regs.fp;
 	int i;
 
 	membuf_store(&to, (unsigned long)fxsave->cwd | 0xffff0000ul);
@@ -91,23 +96,36 @@ static int fpregs_legacy_get(struct task_struct *target,
 	return 0;
 }
 
-static int fpregs_legacy_set(struct task_struct *target,
+int um_i387_from_fxsr(struct user_i387_struct *i387,
+		      const struct user_fxsr_struct *fxsave);
+
+int um_i387_from_fxsr(struct user_i387_struct *i387,
+		      const struct user_fxsr_struct *fxsave)
+{
+	struct membuf to = {
+		.p = i387,
+		.left = sizeof(*i387),
+	};
+
+	return _um_i387_from_fxsr(to, fxsave);
+}
+
+static int fpregs_legacy_get(struct task_struct *target,
 			     const struct user_regset *regset,
-			     unsigned int pos, unsigned int count,
-			     const void *kbuf, const void __user *ubuf)
+			     struct membuf to)
 {
 	struct user_fxsr_struct *fxsave = (void *)target->thread.regs.regs.fp;
-	const struct user_i387_struct *from;
-	struct user_i387_struct buf;
-	int i;
 
-	if (ubuf) {
-		if (copy_from_user(&buf, ubuf, sizeof(buf)))
-			return -EFAULT;
-		from = &buf;
-	} else {
-		from = kbuf;
-	}
+	return _um_i387_from_fxsr(to, fxsave);
+}
+
+int um_fxsr_from_i387(struct user_fxsr_struct *fxsave,
+		      const struct user_i387_struct *from);
+
+int um_fxsr_from_i387(struct user_fxsr_struct *fxsave,
+		      const struct user_i387_struct *from)
+{
+	int i;
 
 	fxsave->cwd = (unsigned short)(from->cwd & 0xffff);
 	fxsave->swd = (unsigned short)(from->swd & 0xffff);
@@ -125,6 +143,26 @@ static int fpregs_legacy_set(struct task_struct *target,
 
 	return 0;
 }
+
+static int fpregs_legacy_set(struct task_struct *target,
+			     const struct user_regset *regset,
+			     unsigned int pos, unsigned int count,
+			     const void *kbuf, const void __user *ubuf)
+{
+	struct user_fxsr_struct *fxsave = (void *)target->thread.regs.regs.fp;
+	const struct user_i387_struct *from;
+	struct user_i387_struct buf;
+
+	if (ubuf) {
+		if (copy_from_user(&buf, ubuf, sizeof(buf)))
+			return -EFAULT;
+		from = &buf;
+	} else {
+		from = kbuf;
+	}
+
+	return um_fxsr_from_i387(fxsave, from);
+}
 #endif
 
 static int genregs_get(struct task_struct *target,
diff --git a/arch/x86/um/shared/sysdep/faultinfo_32.h b/arch/x86/um/shared/sysdep/faultinfo_32.h
index b6f2437ec29c..9193a7790a71 100644
--- a/arch/x86/um/shared/sysdep/faultinfo_32.h
+++ b/arch/x86/um/shared/sysdep/faultinfo_32.h
@@ -29,4 +29,16 @@ struct faultinfo {
 
 #define PTRACE_FULL_FAULTINFO 0
 
+#define ___backtrack_faulted(_faulted)					\
+	asm volatile (							\
+		"movl $__get_kernel_nofault_faulted_%=,%1\n"		\
+		"mov $0, %0\n"						\
+		"jmp _end_%=\n"						\
+		"__get_kernel_nofault_faulted_%=:\n"			\
+		"mov $1, %0;"						\
+		"_end_%=:"						\
+		: "=r" (_faulted),					\
+		  "=m" (current->thread.segv_continue) ::		\
+	)
+
 #endif
diff --git a/arch/x86/um/shared/sysdep/faultinfo_64.h b/arch/x86/um/shared/sysdep/faultinfo_64.h
index ee88f88974ea..61e4ca1e0ab5 100644
--- a/arch/x86/um/shared/sysdep/faultinfo_64.h
+++ b/arch/x86/um/shared/sysdep/faultinfo_64.h
@@ -29,4 +29,16 @@ struct faultinfo {
 
 #define PTRACE_FULL_FAULTINFO 1
 
+#define ___backtrack_faulted(_faulted)					\
+	asm volatile (							\
+		"movq $__get_kernel_nofault_faulted_%=,%1\n"		\
+		"mov $0, %0\n"						\
+		"jmp _end_%=\n"						\
+		"__get_kernel_nofault_faulted_%=:\n"			\
+		"mov $1, %0;"						\
+		"_end_%=:"						\
+		: "=r" (_faulted),					\
+		  "=m" (current->thread.segv_continue) ::		\
+	)
+
 #endif
diff --git a/arch/x86/um/shared/sysdep/kernel-offsets.h b/arch/x86/um/shared/sysdep/kernel-offsets.h
index 48de3a71f845..6fd1ed400399 100644
--- a/arch/x86/um/shared/sysdep/kernel-offsets.h
+++ b/arch/x86/um/shared/sysdep/kernel-offsets.h
@@ -4,7 +4,9 @@
 #include <linux/elf.h>
 #include <linux/crypto.h>
 #include <linux/kbuild.h>
+#include <linux/audit.h>
 #include <asm/mman.h>
+#include <asm/seccomp.h>
 
 /* workaround for a warning with -Wmissing-prototypes */
 void foo(void);
diff --git a/arch/x86/um/shared/sysdep/mcontext.h b/arch/x86/um/shared/sysdep/mcontext.h
index b724c54da316..6fe490cc5b98 100644
--- a/arch/x86/um/shared/sysdep/mcontext.h
+++ b/arch/x86/um/shared/sysdep/mcontext.h
@@ -6,7 +6,16 @@
 #ifndef __SYS_SIGCONTEXT_X86_H
 #define __SYS_SIGCONTEXT_X86_H
 
+#include <stub-data.h>
+
 extern void get_regs_from_mc(struct uml_pt_regs *, mcontext_t *);
+extern void get_mc_from_regs(struct uml_pt_regs *regs, mcontext_t *mc,
+			     int single_stepping);
+
+extern int get_stub_state(struct uml_pt_regs *regs, struct stub_data *data,
+			  unsigned long *fp_size_out);
+extern int set_stub_state(struct uml_pt_regs *regs, struct stub_data *data,
+			  int single_stepping);
 
 #ifdef __i386__
 
diff --git a/arch/x86/um/shared/sysdep/ptrace.h b/arch/x86/um/shared/sysdep/ptrace.h
index 2dd4ca6713f8..8f7476ff6e95 100644
--- a/arch/x86/um/shared/sysdep/ptrace.h
+++ b/arch/x86/um/shared/sysdep/ptrace.h
@@ -74,8 +74,6 @@ struct uml_pt_regs {
 #define UPT_FAULTINFO(r) (&(r)->faultinfo)
 #define UPT_IS_USER(r) ((r)->is_user)
 
-extern int user_context(unsigned long sp);
-
 extern int arch_init_registers(int pid);
 
 #endif /* __SYSDEP_X86_PTRACE_H */
diff --git a/arch/x86/um/shared/sysdep/stub-data.h b/arch/x86/um/shared/sysdep/stub-data.h
new file mode 100644
index 000000000000..82b1b7f8ac3d
--- /dev/null
+++ b/arch/x86/um/shared/sysdep/stub-data.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ARCH_STUB_DATA_H
+#define __ARCH_STUB_DATA_H
+
+#ifdef __i386__
+#include <generated/asm-offsets.h>
+#include <asm/ldt.h>
+
+struct stub_data_arch {
+	int sync;
+	struct user_desc tls[UM_KERN_GDT_ENTRY_TLS_ENTRIES];
+};
+#else
+#define STUB_SYNC_FS_BASE (1 << 0)
+#define STUB_SYNC_GS_BASE (1 << 1)
+struct stub_data_arch {
+	int sync;
+	unsigned long fs_base;
+	unsigned long gs_base;
+};
+#endif
+
+#endif /* __ARCH_STUB_DATA_H */
diff --git a/arch/x86/um/shared/sysdep/stub.h b/arch/x86/um/shared/sysdep/stub.h
index dc89f4423454..4fa58f5b4fca 100644
--- a/arch/x86/um/shared/sysdep/stub.h
+++ b/arch/x86/um/shared/sysdep/stub.h
@@ -13,3 +13,5 @@
 
 extern void stub_segv_handler(int, siginfo_t *, void *);
 extern void stub_syscall_handler(void);
+extern void stub_signal_interrupt(int, siginfo_t *, void *);
+extern void stub_signal_restorer(void);
diff --git a/arch/x86/um/shared/sysdep/stub_32.h b/arch/x86/um/shared/sysdep/stub_32.h
index 390988132c0a..df568fc3ceb4 100644
--- a/arch/x86/um/shared/sysdep/stub_32.h
+++ b/arch/x86/um/shared/sysdep/stub_32.h
@@ -131,4 +131,17 @@ static __always_inline void *get_stub_data(void)
 		"call *%%eax ;"						\
 		:: "i" ((1 + STUB_DATA_PAGES) * UM_KERN_PAGE_SIZE),	\
 		   "i" (&fn))
+
+static __always_inline void
+stub_seccomp_restore_state(struct stub_data_arch *arch)
+{
+	for (int i = 0; i < sizeof(arch->tls) / sizeof(arch->tls[0]); i++) {
+		if (arch->sync & (1 << i))
+			stub_syscall1(__NR_set_thread_area,
+				      (unsigned long) &arch->tls[i]);
+	}
+
+	arch->sync = 0;
+}
+
 #endif
diff --git a/arch/x86/um/shared/sysdep/stub_64.h b/arch/x86/um/shared/sysdep/stub_64.h
index 294affbec742..9cfd31afa769 100644
--- a/arch/x86/um/shared/sysdep/stub_64.h
+++ b/arch/x86/um/shared/sysdep/stub_64.h
@@ -10,6 +10,7 @@
 #include <sysdep/ptrace_user.h>
 #include <generated/asm-offsets.h>
 #include <linux/stddef.h>
+#include <asm/prctl.h>
 
 #define STUB_MMAP_NR __NR_mmap
 #define MMAP_OFFSET(o) (o)
@@ -134,4 +135,20 @@ static __always_inline void *get_stub_data(void)
 		"call *%%rax ;"						\
 		:: "i" ((1 + STUB_DATA_PAGES) * UM_KERN_PAGE_SIZE),	\
 		   "i" (&fn))
+
+static __always_inline void
+stub_seccomp_restore_state(struct stub_data_arch *arch)
+{
+	/*
+	 * We could use _writefsbase_u64/_writegsbase_u64 if the host reports
+	 * support in the hwcaps (HWCAP2_FSGSBASE).
+	 */
+	if (arch->sync & STUB_SYNC_FS_BASE)
+		stub_syscall2(__NR_arch_prctl, ARCH_SET_FS, arch->fs_base);
+	if (arch->sync & STUB_SYNC_GS_BASE)
+		stub_syscall2(__NR_arch_prctl, ARCH_SET_GS, arch->gs_base);
+
+	arch->sync = 0;
+}
+
 #endif
diff --git a/arch/x86/um/signal.c b/arch/x86/um/signal.c
index 75087e85b6fd..2934e170b0fe 100644
--- a/arch/x86/um/signal.c
+++ b/arch/x86/um/signal.c
@@ -187,7 +187,12 @@ static int copy_sc_to_user(struct sigcontext __user *to,
 	 * Put magic/size values for userspace. We do not bother to verify them
 	 * later on, however, userspace needs them should it try to read the
 	 * XSTATE data. And ptrace does not fill in these parts.
+	 *
+	 * Skip this if we do not have an XSTATE frame.
 	 */
+	if (host_fp_size <= sizeof(to_fp64->fpstate))
+		return 0;
+
 	BUILD_BUG_ON(sizeof(int) != FP_XSTATE_MAGIC2_SIZE);
 #ifdef CONFIG_X86_32
 	__put_user(offsetof(struct _fpstate_32, _fxsr_env) +
@@ -367,11 +372,13 @@ int setup_signal_stack_si(unsigned long stack_top, struct ksignal *ksig,
 	int err = 0, sig = ksig->sig;
 	unsigned long fp_to;
 
-	frame = (struct rt_sigframe __user *)
-		round_down(stack_top - sizeof(struct rt_sigframe), 16);
+	frame = (void __user *)stack_top - sizeof(struct rt_sigframe);
 
 	/* Add required space for math frame */
-	frame = (struct rt_sigframe __user *)((unsigned long)frame - math_size);
+	frame = (void __user *)((unsigned long)frame - math_size);
+
+	/* ABI requires 16 byte boundary alignment */
+	frame = (void __user *)round_down((unsigned long)frame, 16);
 
 	/* Subtract 128 for a red zone and 8 for proper alignment */
 	frame = (struct rt_sigframe __user *) ((unsigned long) frame - 128 - 8);
diff --git a/arch/x86/um/tls_32.c b/arch/x86/um/tls_32.c
index fbb129023080..cb3f17627d16 100644
--- a/arch/x86/um/tls_32.c
+++ b/arch/x86/um/tls_32.c
@@ -12,6 +12,7 @@
 #include <skas.h>
 #include <sysdep/tls.h>
 #include <asm/desc.h>
+#include <stub-data.h>
 
 /*
  * If needed we can detect when it's uninitialized.
@@ -21,14 +22,25 @@
 static int host_supports_tls = -1;
 int host_gdt_entry_tls_min;
 
-static int do_set_thread_area(struct user_desc *info)
+static int do_set_thread_area(struct task_struct* task, struct user_desc *info)
 {
 	int ret;
-	u32 cpu;
 
-	cpu = get_cpu();
-	ret = os_set_thread_area(info, userspace_pid[cpu]);
-	put_cpu();
+	if (info->entry_number < host_gdt_entry_tls_min ||
+	    info->entry_number >= host_gdt_entry_tls_min + GDT_ENTRY_TLS_ENTRIES)
+		return -EINVAL;
+
+	if (using_seccomp) {
+		int idx = info->entry_number - host_gdt_entry_tls_min;
+		struct stub_data *data = (void *)task->mm->context.id.stack;
+
+		data->arch_data.tls[idx] = *info;
+		data->arch_data.sync |= BIT(idx);
+
+		return 0;
+	}
+
+	ret = os_set_thread_area(info, task->mm->context.id.pid);
 
 	if (ret)
 		printk(KERN_ERR "PTRACE_SET_THREAD_AREA failed, err = %d, "
@@ -97,7 +109,7 @@ static int load_TLS(int flags, struct task_struct *to)
 		if (!(flags & O_FORCE) && curr->flushed)
 			continue;
 
-		ret = do_set_thread_area(&curr->tls);
+		ret = do_set_thread_area(current, &curr->tls);
 		if (ret)
 			goto out;
 
@@ -275,7 +287,7 @@ SYSCALL_DEFINE1(set_thread_area, struct user_desc __user *, user_desc)
 			return -EFAULT;
 	}
 
-	ret = do_set_thread_area(&info);
+	ret = do_set_thread_area(current, &info);
 	if (ret)
 		return ret;
 	return set_tls_entry(current, &info, idx, 1);
diff --git a/arch/x86/um/vdso/vma.c b/arch/x86/um/vdso/vma.c
index f238f7b33cdd..dc8dfb2abd80 100644
--- a/arch/x86/um/vdso/vma.c
+++ b/arch/x86/um/vdso/vma.c
@@ -12,33 +12,22 @@
 
 static unsigned int __read_mostly vdso_enabled = 1;
 unsigned long um_vdso_addr;
+static struct page *um_vdso;
 
 extern unsigned long task_size;
 extern char vdso_start[], vdso_end[];
 
-static struct page **vdsop;
-
 static int __init init_vdso(void)
 {
-	struct page *um_vdso;
-
 	BUG_ON(vdso_end - vdso_start > PAGE_SIZE);
 
 	um_vdso_addr = task_size - PAGE_SIZE;
 
-	vdsop = kmalloc(sizeof(struct page *), GFP_KERNEL);
-	if (!vdsop)
-		goto oom;
-
 	um_vdso = alloc_page(GFP_KERNEL);
-	if (!um_vdso) {
-		kfree(vdsop);
-
+	if (!um_vdso)
 		goto oom;
-	}
 
 	copy_page(page_address(um_vdso), vdso_start);
-	*vdsop = um_vdso;
 
 	return 0;
 
@@ -56,6 +45,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 	struct mm_struct *mm = current->mm;
 	static struct vm_special_mapping vdso_mapping = {
 		.name = "[vdso]",
+		.pages = &um_vdso,
 	};
 
 	if (!vdso_enabled)
@@ -64,7 +54,6 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 	if (mmap_write_lock_killable(mm))
 		return -EINTR;
 
-	vdso_mapping.pages = vdsop;
 	vma = _install_special_mapping(mm, um_vdso_addr, PAGE_SIZE,
 		VM_READ|VM_EXEC|
 		VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,