23 files changed, 115 insertions, 83 deletions

diff --git a/arch/x86/kernel/amd_nb.c b/arch/x86/kernel/amd_nb.c
index cc51275c8759..002aedc69393 100644
--- a/arch/x86/kernel/amd_nb.c
+++ b/arch/x86/kernel/amd_nb.c
@@ -1,6 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Shared support code for AMD K8 northbridges and derivates.
- * Copyright 2006 Andi Kleen, SUSE Labs. Subject to GPLv2.
+ * Copyright 2006 Andi Kleen, SUSE Labs.
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 177aa8ef2afa..85be316665b4 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1464,7 +1464,8 @@ static void apic_pending_intr_clear(void)
 		if (queued) {
 			if (boot_cpu_has(X86_FEATURE_TSC) && cpu_khz) {
 				ntsc = rdtsc();
-				max_loops = (cpu_khz << 10) - (ntsc - tsc);
+				max_loops = (long long)cpu_khz << 10;
+				max_loops -= ntsc - tsc;
 			} else {
 				max_loops--;
 			}
diff --git a/arch/x86/kernel/apic/msi.c b/arch/x86/kernel/apic/msi.c
index 72a94401f9e0..dad0dd759de2 100644
--- a/arch/x86/kernel/apic/msi.c
+++ b/arch/x86/kernel/apic/msi.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Support of MSI, HPET and DMAR interrupts.
  *
@@ -5,10 +6,6 @@
  *	Moved from arch/x86/kernel/apic/io_apic.c.
  * Jiang Liu <jiang.liu@linux.intel.com>
  *	Convert to hierarchical irqdomain
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 #include <linux/mm.h>
 #include <linux/interrupt.h>
diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c
index 3173e07d3791..e7cb78aed644 100644
--- a/arch/x86/kernel/apic/vector.c
+++ b/arch/x86/kernel/apic/vector.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Local APIC related interfaces to support IOAPIC, MSI, etc.
  *
@@ -5,10 +6,6 @@
  *	Moved from arch/x86/kernel/apic/io_apic.c.
  * Jiang Liu <jiang.liu@linux.intel.com>
  *	Enable support of hierarchical irqdomains
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 #include <linux/interrupt.h>
 #include <linux/irq.h>
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 03b4cc0ec3a7..66ca906aa790 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -836,6 +836,16 @@ static enum ssb_mitigation __init __ssb_select_mitigation(void)
 	}
 
 	/*
+	 * If SSBD is controlled by the SPEC_CTRL MSR, then set the proper
+	 * bit in the mask to allow guests to use the mitigation even in the
+	 * case where the host does not enable it.
+	 */
+	if (static_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD) ||
+	    static_cpu_has(X86_FEATURE_AMD_SSBD)) {
+		x86_spec_ctrl_mask |= SPEC_CTRL_SSBD;
+	}
+
+	/*
 	 * We have three CPU feature flags that are in play here:
 	 *  - X86_BUG_SPEC_STORE_BYPASS - CPU is susceptible.
 	 *  - X86_FEATURE_SSBD - CPU is able to turn off speculative store bypass
@@ -852,7 +862,6 @@ static enum ssb_mitigation __init __ssb_select_mitigation(void)
 			x86_amd_ssb_disable();
 		} else {
 			x86_spec_ctrl_base |= SPEC_CTRL_SSBD;
-			x86_spec_ctrl_mask |= SPEC_CTRL_SSBD;
 			wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base);
 		}
 	}
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index 70a04436380e..cb0fdcaf1415 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -789,13 +789,16 @@ static struct syscore_ops mc_syscore_ops = {
 	.resume			= mc_bp_resume,
 };
 
-static int mc_cpu_online(unsigned int cpu)
+static int mc_cpu_starting(unsigned int cpu)
 {
-	struct device *dev;
-
-	dev = get_cpu_device(cpu);
 	microcode_update_cpu(cpu);
 	pr_debug("CPU%d added\n", cpu);
+	return 0;
+}
+
+static int mc_cpu_online(unsigned int cpu)
+{
+	struct device *dev = get_cpu_device(cpu);
 
 	if (sysfs_create_group(&dev->kobj, &mc_attr_group))
 		pr_err("Failed to create group for CPU%d\n", cpu);
@@ -872,6 +875,8 @@ int __init microcode_init(void)
 		goto out_ucode_group;
 
 	register_syscore_ops(&mc_syscore_ops);
+	cpuhp_setup_state_nocalls(CPUHP_AP_MICROCODE_LOADER, "x86/microcode:starting",
+				  mc_cpu_starting, NULL);
 	cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/microcode:online",
 				  mc_cpu_online, mc_cpu_down_prep);
 
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 7ee93125a211..397206f23d14 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -360,6 +360,9 @@ static void update_mba_bw(struct rdtgroup *rgrp, struct rdt_domain *dom_mbm)
 	struct list_head *head;
 	struct rdtgroup *entry;
 
+	if (!is_mbm_local_enabled())
+		return;
+
 	r_mba = &rdt_resources_all[RDT_RESOURCE_MBA];
 	closid = rgrp->closid;
 	rmid = rgrp->mon.rmid;
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 2f48f208f7e2..2f4824793798 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -796,8 +796,12 @@ static int rdt_bit_usage_show(struct kernfs_open_file *of,
 			      struct seq_file *seq, void *v)
 {
 	struct rdt_resource *r = of->kn->parent->priv;
-	u32 sw_shareable = 0, hw_shareable = 0;
-	u32 exclusive = 0, pseudo_locked = 0;
+	/*
+	 * Use unsigned long even though only 32 bits are used to ensure
+	 * test_bit() is used safely.
+	 */
+	unsigned long sw_shareable = 0, hw_shareable = 0;
+	unsigned long exclusive = 0, pseudo_locked = 0;
 	struct rdt_domain *dom;
 	int i, hwb, swb, excl, psl;
 	enum rdtgrp_mode mode;
@@ -842,10 +846,10 @@ static int rdt_bit_usage_show(struct kernfs_open_file *of,
 		}
 		for (i = r->cache.cbm_len - 1; i >= 0; i--) {
 			pseudo_locked = dom->plr ? dom->plr->cbm : 0;
-			hwb = test_bit(i, (unsigned long *)&hw_shareable);
-			swb = test_bit(i, (unsigned long *)&sw_shareable);
-			excl = test_bit(i, (unsigned long *)&exclusive);
-			psl = test_bit(i, (unsigned long *)&pseudo_locked);
+			hwb = test_bit(i, &hw_shareable);
+			swb = test_bit(i, &sw_shareable);
+			excl = test_bit(i, &exclusive);
+			psl = test_bit(i, &pseudo_locked);
 			if (hwb && swb)
 				seq_putc(seq, 'X');
 			else if (hwb && !swb)
@@ -2486,26 +2490,19 @@ out_destroy:
  */
 static void cbm_ensure_valid(u32 *_val, struct rdt_resource *r)
 {
-	/*
-	 * Convert the u32 _val to an unsigned long required by all the bit
-	 * operations within this function. No more than 32 bits of this
-	 * converted value can be accessed because all bit operations are
-	 * additionally provided with cbm_len that is initialized during
-	 * hardware enumeration using five bits from the EAX register and
-	 * thus never can exceed 32 bits.
-	 */
-	unsigned long *val = (unsigned long *)_val;
+	unsigned long val = *_val;
 	unsigned int cbm_len = r->cache.cbm_len;
 	unsigned long first_bit, zero_bit;
 
-	if (*val == 0)
+	if (val == 0)
 		return;
 
-	first_bit = find_first_bit(val, cbm_len);
-	zero_bit = find_next_zero_bit(val, cbm_len, first_bit);
+	first_bit = find_first_bit(&val, cbm_len);
+	zero_bit = find_next_zero_bit(&val, cbm_len, first_bit);
 
 	/* Clear any remaining bits to ensure contiguous region */
-	bitmap_clear(val, zero_bit, cbm_len - zero_bit);
+	bitmap_clear(&val, zero_bit, cbm_len - zero_bit);
+	*_val = (u32)val;
 }
 
 /*
@@ -2534,7 +2531,12 @@ static int __init_one_rdt_domain(struct rdt_domain *d, struct rdt_resource *r,
 		if (closid_allocated(i) && i != closid) {
 			mode = rdtgroup_mode_by_closid(i);
 			if (mode == RDT_MODE_PSEUDO_LOCKSETUP)
-				break;
+				/*
+				 * ctrl values for locksetup aren't relevant
+				 * until the schemata is written, and the mode
+				 * becomes RDT_MODE_PSEUDO_LOCKED.
+				 */
+				continue;
 			/*
 			 * If CDP is active include peer domain's
 			 * usage to ensure there is no overlap
diff --git a/arch/x86/kernel/eisa.c b/arch/x86/kernel/eisa.c
index e8c8c5d78dbd..e963344b0449 100644
--- a/arch/x86/kernel/eisa.c
+++ b/arch/x86/kernel/eisa.c
@@ -1,7 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * EISA specific code
- *
- * This file is licensed under the GPL V2
  */
 #include <linux/ioport.h>
 #include <linux/eisa.h>
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 466fca686fb9..649fbc3fcf9f 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -102,7 +102,7 @@ static void __kernel_fpu_begin(void)
 
 	kernel_fpu_disable();
 
-	if (current->mm) {
+	if (!(current->flags & PF_KTHREAD)) {
 		if (!test_thread_flag(TIF_NEED_FPU_LOAD)) {
 			set_thread_flag(TIF_NEED_FPU_LOAD);
 			/*
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index 5a8d118bc423..0071b794ed19 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -5,6 +5,7 @@
 
 #include <linux/compat.h>
 #include <linux/cpu.h>
+#include <linux/pagemap.h>
 
 #include <asm/fpu/internal.h>
 #include <asm/fpu/signal.h>
@@ -61,6 +62,11 @@ static inline int save_fsave_header(struct task_struct *tsk, void __user *buf)
 		struct user_i387_ia32_struct env;
 		struct _fpstate_32 __user *fp = buf;
 
+		fpregs_lock();
+		if (!test_thread_flag(TIF_NEED_FPU_LOAD))
+			copy_fxregs_to_kernel(&tsk->thread.fpu);
+		fpregs_unlock();
+
 		convert_from_fxsr(&env, tsk);
 
 		if (__copy_to_user(buf, &env, sizeof(env)) ||
@@ -189,15 +195,7 @@ retry:
 	fpregs_unlock();
 
 	if (ret) {
-		int aligned_size;
-		int nr_pages;
-
-		aligned_size = offset_in_page(buf_fx) + fpu_user_xstate_size;
-		nr_pages = DIV_ROUND_UP(aligned_size, PAGE_SIZE);
-
-		ret = get_user_pages_unlocked((unsigned long)buf_fx, nr_pages,
-					      NULL, FOLL_WRITE);
-		if (ret == nr_pages)
+		if (!fault_in_pages_writeable(buf_fx, fpu_user_xstate_size))
 			goto retry;
 		return -EFAULT;
 	}
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 0927bb158ffc..76228525acd0 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -22,6 +22,7 @@
 #include <linux/init.h>
 #include <linux/list.h>
 #include <linux/module.h>
+#include <linux/memory.h>
 
 #include <trace/syscall.h>
 
@@ -34,16 +35,25 @@
 #ifdef CONFIG_DYNAMIC_FTRACE
 
 int ftrace_arch_code_modify_prepare(void)
+    __acquires(&text_mutex)
 {
+	/*
+	 * Need to grab text_mutex to prevent a race from module loading
+	 * and live kernel patching from changing the text permissions while
+	 * ftrace has it set to "read/write".
+	 */
+	mutex_lock(&text_mutex);
 	set_kernel_text_rw();
 	set_all_modules_text_rw();
 	return 0;
 }
 
 int ftrace_arch_code_modify_post_process(void)
+    __releases(&text_mutex)
 {
 	set_all_modules_text_ro();
 	set_kernel_text_ro();
+	mutex_unlock(&text_mutex);
 	return 0;
 }
 
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 16b1cbd3a61e..29ffa495bd1c 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -184,24 +184,25 @@ unsigned long __head __startup_64(unsigned long physaddr,
 	pgtable_flags = _KERNPG_TABLE_NOENC + sme_get_me_mask();
 
 	if (la57) {
-		p4d = fixup_pointer(early_dynamic_pgts[next_early_pgt++], physaddr);
+		p4d = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++],
+				    physaddr);
 
 		i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
 		pgd[i + 0] = (pgdval_t)p4d + pgtable_flags;
 		pgd[i + 1] = (pgdval_t)p4d + pgtable_flags;
 
-		i = (physaddr >> P4D_SHIFT) % PTRS_PER_P4D;
-		p4d[i + 0] = (pgdval_t)pud + pgtable_flags;
-		p4d[i + 1] = (pgdval_t)pud + pgtable_flags;
+		i = physaddr >> P4D_SHIFT;
+		p4d[(i + 0) % PTRS_PER_P4D] = (pgdval_t)pud + pgtable_flags;
+		p4d[(i + 1) % PTRS_PER_P4D] = (pgdval_t)pud + pgtable_flags;
 	} else {
 		i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
 		pgd[i + 0] = (pgdval_t)pud + pgtable_flags;
 		pgd[i + 1] = (pgdval_t)pud + pgtable_flags;
 	}
 
-	i = (physaddr >> PUD_SHIFT) % PTRS_PER_PUD;
-	pud[i + 0] = (pudval_t)pmd + pgtable_flags;
-	pud[i + 1] = (pudval_t)pmd + pgtable_flags;
+	i = physaddr >> PUD_SHIFT;
+	pud[(i + 0) % PTRS_PER_PUD] = (pudval_t)pmd + pgtable_flags;
+	pud[(i + 1) % PTRS_PER_PUD] = (pudval_t)pmd + pgtable_flags;
 
 	pmd_entry = __PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL;
 	/* Filter out unsupported __PAGE_KERNEL_* bits: */
@@ -211,8 +212,9 @@ unsigned long __head __startup_64(unsigned long physaddr,
 	pmd_entry +=  physaddr;
 
 	for (i = 0; i < DIV_ROUND_UP(_end - _text, PMD_SIZE); i++) {
-		int idx = i + (physaddr >> PMD_SHIFT) % PTRS_PER_PMD;
-		pmd[idx] = pmd_entry + i * PMD_SIZE;
+		int idx = i + (physaddr >> PMD_SHIFT);
+
+		pmd[idx % PTRS_PER_PMD] = pmd_entry + i * PMD_SIZE;
 	}
 
 	/*
diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index 6d8917875f44..d2482bbbe3d0 100644
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -1,7 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Interrupt descriptor table related code
- *
- * This file is licensed under the GPL V2
  */
 #include <linux/interrupt.h>
 
diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index 22f60dd26460..f03237e3f192 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -1,12 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Kexec bzImage loader
  *
  * Copyright (C) 2014 Red Hat Inc.
  * Authors:
  *      Vivek Goyal <vgoyal@redhat.com>
- *
- * This source code is licensed under the GNU General Public License,
- * Version 2.  See the file COPYING for more details.
  */
 
 #define pr_fmt(fmt)	"kexec-bzImage64: " fmt
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
index 9a8c1648fc9a..6690c5652aeb 100644
--- a/arch/x86/kernel/kgdb.c
+++ b/arch/x86/kernel/kgdb.c
@@ -758,7 +758,7 @@ int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
 		       BREAK_INSTR_SIZE);
 	bpt->type = BP_POKE_BREAKPOINT;
 
-	return err;
+	return 0;
 }
 
 int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
diff --git a/arch/x86/kernel/machine_kexec_32.c b/arch/x86/kernel/machine_kexec_32.c
index 5409c2800ab5..77854b192fef 100644
--- a/arch/x86/kernel/machine_kexec_32.c
+++ b/arch/x86/kernel/machine_kexec_32.c
@@ -1,9 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * handle transition of Linux booting another kernel
  * Copyright (C) 2002-2005 Eric Biederman  <ebiederm@xmission.com>
- *
- * This source code is licensed under the GNU General Public License,
- * Version 2.  See the file COPYING for more details.
  */
 
 #include <linux/mm.h>
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index ceba408ea982..d7be2376ac0b 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -1,9 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * handle transition of Linux booting another kernel
  * Copyright (C) 2002-2005 Eric Biederman  <ebiederm@xmission.com>
- *
- * This source code is licensed under the GNU General Public License,
- * Version 2.  See the file COPYING for more details.
  */
 
 #define pr_fmt(fmt)	"kexec: " fmt
diff --git a/arch/x86/kernel/perf_regs.c b/arch/x86/kernel/perf_regs.c
index 07c30ee17425..bb7e1132290b 100644
--- a/arch/x86/kernel/perf_regs.c
+++ b/arch/x86/kernel/perf_regs.c
@@ -74,6 +74,9 @@ u64 perf_reg_value(struct pt_regs *regs, int idx)
 	return regs_get_register(regs, pt_regs_offset[idx]);
 }
 
+#define PERF_REG_X86_RESERVED	(((1ULL << PERF_REG_X86_XMM0) - 1) & \
+				 ~((1ULL << PERF_REG_X86_MAX) - 1))
+
 #ifdef CONFIG_X86_32
 #define REG_NOSUPPORT ((1ULL << PERF_REG_X86_R8) | \
 		       (1ULL << PERF_REG_X86_R9) | \
@@ -86,7 +89,7 @@ u64 perf_reg_value(struct pt_regs *regs, int idx)
 
 int perf_reg_validate(u64 mask)
 {
-	if (!mask || (mask & REG_NOSUPPORT))
+	if (!mask || (mask & (REG_NOSUPPORT | PERF_REG_X86_RESERVED)))
 		return -EINVAL;
 
 	return 0;
@@ -112,7 +115,7 @@ void perf_get_regs_user(struct perf_regs *regs_user,
 
 int perf_reg_validate(u64 mask)
 {
-	if (!mask || (mask & REG_NOSUPPORT))
+	if (!mask || (mask & (REG_NOSUPPORT | PERF_REG_X86_RESERVED)))
 		return -EINVAL;
 
 	return 0;
diff --git a/arch/x86/kernel/relocate_kernel_32.S b/arch/x86/kernel/relocate_kernel_32.S
index 77630d57e7bf..ee26df08002e 100644
--- a/arch/x86/kernel/relocate_kernel_32.S
+++ b/arch/x86/kernel/relocate_kernel_32.S
@@ -1,9 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * relocate_kernel.S - put the kernel image in place to boot
  * Copyright (C) 2002-2004 Eric Biederman  <ebiederm@xmission.com>
- *
- * This source code is licensed under the GNU General Public License,
- * Version 2.  See the file COPYING for more details.
  */
 
 #include <linux/linkage.h>
diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S
index 11eda21eb697..c51ccff5cd01 100644
--- a/arch/x86/kernel/relocate_kernel_64.S
+++ b/arch/x86/kernel/relocate_kernel_64.S
@@ -1,9 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * relocate_kernel.S - put the kernel image in place to boot
  * Copyright (C) 2002-2005 Eric Biederman  <ebiederm@xmission.com>
- *
- * This source code is licensed under the GNU General Public License,
- * Version 2.  See the file COPYING for more details.
  */
 
 #include <linux/linkage.h>
diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
index 33b66b5c5aec..72b997eaa1fc 100644
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -82,9 +82,9 @@ static struct orc_entry *orc_find(unsigned long ip);
  * But they are copies of the ftrace entries that are static and
  * defined in ftrace_*.S, which do have orc entries.
  *
- * If the undwinder comes across a ftrace trampoline, then find the
+ * If the unwinder comes across a ftrace trampoline, then find the
  * ftrace function that was used to create it, and use that ftrace
- * function's orc entrie, as the placement of the return code in
+ * function's orc entry, as the placement of the return code in
  * the stack will be identical.
  */
 static struct orc_entry *orc_ftrace_find(unsigned long ip)
@@ -128,6 +128,16 @@ static struct orc_entry null_orc_entry = {
 	.type = ORC_TYPE_CALL
 };
 
+/* Fake frame pointer entry -- used as a fallback for generated code */
+static struct orc_entry orc_fp_entry = {
+	.type		= ORC_TYPE_CALL,
+	.sp_reg		= ORC_REG_BP,
+	.sp_offset	= 16,
+	.bp_reg		= ORC_REG_PREV_SP,
+	.bp_offset	= -16,
+	.end		= 0,
+};
+
 static struct orc_entry *orc_find(unsigned long ip)
 {
 	static struct orc_entry *orc;
@@ -392,8 +402,16 @@ bool unwind_next_frame(struct unwind_state *state)
 	 * calls and calls to noreturn functions.
 	 */
 	orc = orc_find(state->signal ? state->ip : state->ip - 1);
-	if (!orc)
-		goto err;
+	if (!orc) {
+		/*
+		 * As a fallback, try to assume this code uses a frame pointer.
+		 * This is useful for generated code, like BPF, which ORC
+		 * doesn't know about.  This is just a guess, so the rest of
+		 * the unwind is no longer considered reliable.
+		 */
+		orc = &orc_fp_entry;
+		state->error = true;
+	}
 
 	/* End-of-stack check for kernel threads: */
 	if (orc->sp_reg == ORC_REG_UNDEFINED) {
diff --git a/arch/x86/kernel/verify_cpu.S b/arch/x86/kernel/verify_cpu.S
index 3d3c2f71f617..a024c4f7ba56 100644
--- a/arch/x86/kernel/verify_cpu.S
+++ b/arch/x86/kernel/verify_cpu.S
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  *
  *	verify_cpu.S - Code for cpu long mode and SSE verification. This
@@ -9,9 +10,6 @@
  *	Copyright (c) 2007  Vivek Goyal (vgoyal@in.ibm.com)
  *	Copyright (c) 2010  Kees Cook (kees.cook@canonical.com)
  *
- * 	This source code is licensed under the GNU General Public License,
- * 	Version 2.  See the file COPYING for more details.
- *
  *	This is a common code for verification whether CPU supports
  * 	long mode and SSE or not. It is not called directly instead this
  *	file is included at various places and compiled in that context.