1 files changed, 673 insertions, 121 deletions

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 659ae8094ed5..fba7ca102a8c 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -1,41 +1,30 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Based on arch/arm/kernel/process.c
  *
  * Original Copyright (C) 1995  Linus Torvalds
  * Copyright (C) 1996-2000 Russell King - Converted to ARM.
  * Copyright (C) 2012 ARM Ltd.
- *
- * 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.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
-
-#include <stdarg.h>
-
 #include <linux/compat.h>
 #include <linux/efi.h>
+#include <linux/elf.h>
 #include <linux/export.h>
 #include <linux/sched.h>
 #include <linux/sched/debug.h>
 #include <linux/sched/task.h>
 #include <linux/sched/task_stack.h>
 #include <linux/kernel.h>
+#include <linux/mman.h>
 #include <linux/mm.h>
+#include <linux/nospec.h>
 #include <linux/stddef.h>
+#include <linux/sysctl.h>
 #include <linux/unistd.h>
 #include <linux/user.h>
 #include <linux/delay.h>
 #include <linux/reboot.h>
 #include <linux/interrupt.h>
-#include <linux/kallsyms.h>
 #include <linux/init.h>
 #include <linux/cpu.h>
 #include <linux/elfcore.h>
@@ -49,19 +38,29 @@
 #include <linux/notifier.h>
 #include <trace/events/power.h>
 #include <linux/percpu.h>
+#include <linux/thread_info.h>
+#include <linux/prctl.h>
+#include <linux/stacktrace.h>
 
 #include <asm/alternative.h>
+#include <asm/arch_timer.h>
 #include <asm/compat.h>
+#include <asm/cpufeature.h>
 #include <asm/cacheflush.h>
 #include <asm/exec.h>
 #include <asm/fpsimd.h>
+#include <asm/gcs.h>
 #include <asm/mmu_context.h>
+#include <asm/mte.h>
 #include <asm/processor.h>
+#include <asm/pointer_auth.h>
 #include <asm/stacktrace.h>
+#include <asm/switch_to.h>
+#include <asm/system_misc.h>
 
-#ifdef CONFIG_CC_STACKPROTECTOR
+#if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK)
 #include <linux/stackprotector.h>
-unsigned long __stack_chk_guard __read_mostly;
+unsigned long __stack_chk_guard __ro_after_init;
 EXPORT_SYMBOL(__stack_chk_guard);
 #endif
 
@@ -71,25 +70,8 @@ EXPORT_SYMBOL(__stack_chk_guard);
 void (*pm_power_off)(void);
 EXPORT_SYMBOL_GPL(pm_power_off);
 
-void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
-
-/*
- * This is our default idle handler.
- */
-void arch_cpu_idle(void)
-{
-	/*
-	 * This should do all the clock switching and wait for interrupt
-	 * tricks
-	 */
-	trace_cpu_idle_rcuidle(1, smp_processor_id());
-	cpu_do_idle();
-	local_irq_enable();
-	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id());
-}
-
 #ifdef CONFIG_HOTPLUG_CPU
-void arch_cpu_idle_dead(void)
+void __noreturn arch_cpu_idle_dead(void)
 {
        cpu_die();
 }
@@ -102,11 +84,11 @@ void arch_cpu_idle_dead(void)
  * to execute e.g. a RAM-based pin loop is not sufficient. This allows the
  * kexec'd kernel to use any and all RAM as it sees fit, without having to
  * avoid any code or data used by any SW CPU pin loop. The CPU hotplug
- * functionality embodied in disable_nonboot_cpus() to achieve this.
+ * functionality embodied in smpt_shutdown_nonboot_cpus() to achieve this.
  */
 void machine_shutdown(void)
 {
-	disable_nonboot_cpus();
+	smp_shutdown_nonboot_cpus(reboot_cpu);
 }
 
 /*
@@ -131,8 +113,7 @@ void machine_power_off(void)
 {
 	local_irq_disable();
 	smp_send_stop();
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
 }
 
 /*
@@ -158,10 +139,7 @@ void machine_restart(char *cmd)
 		efi_reboot(reboot_mode, NULL);
 
 	/* Now call the architecture specific reboot code. */
-	if (arm_pm_restart)
-		arm_pm_restart(reboot_mode, cmd);
-	else
-		do_kernel_restart(cmd);
+	do_kernel_restart(cmd);
 
 	/*
 	 * Whoops - the architecture was unable to reboot.
@@ -170,6 +148,57 @@ void machine_restart(char *cmd)
 	while (1);
 }
 
+#define bstr(suffix, str) [PSR_BTYPE_ ## suffix >> PSR_BTYPE_SHIFT] = str
+static const char *const btypes[] = {
+	bstr(NONE, "--"),
+	bstr(  JC, "jc"),
+	bstr(   C, "-c"),
+	bstr(  J , "j-")
+};
+#undef bstr
+
+static void print_pstate(struct pt_regs *regs)
+{
+	u64 pstate = regs->pstate;
+
+	if (compat_user_mode(regs)) {
+		printk("pstate: %08llx (%c%c%c%c %c %s %s %c%c%c %cDIT %cSSBS)\n",
+			pstate,
+			pstate & PSR_AA32_N_BIT ? 'N' : 'n',
+			pstate & PSR_AA32_Z_BIT ? 'Z' : 'z',
+			pstate & PSR_AA32_C_BIT ? 'C' : 'c',
+			pstate & PSR_AA32_V_BIT ? 'V' : 'v',
+			pstate & PSR_AA32_Q_BIT ? 'Q' : 'q',
+			pstate & PSR_AA32_T_BIT ? "T32" : "A32",
+			pstate & PSR_AA32_E_BIT ? "BE" : "LE",
+			pstate & PSR_AA32_A_BIT ? 'A' : 'a',
+			pstate & PSR_AA32_I_BIT ? 'I' : 'i',
+			pstate & PSR_AA32_F_BIT ? 'F' : 'f',
+			pstate & PSR_AA32_DIT_BIT ? '+' : '-',
+			pstate & PSR_AA32_SSBS_BIT ? '+' : '-');
+	} else {
+		const char *btype_str = btypes[(pstate & PSR_BTYPE_MASK) >>
+					       PSR_BTYPE_SHIFT];
+
+		printk("pstate: %08llx (%c%c%c%c %c%c%c%c %cPAN %cUAO %cTCO %cDIT %cSSBS BTYPE=%s)\n",
+			pstate,
+			pstate & PSR_N_BIT ? 'N' : 'n',
+			pstate & PSR_Z_BIT ? 'Z' : 'z',
+			pstate & PSR_C_BIT ? 'C' : 'c',
+			pstate & PSR_V_BIT ? 'V' : 'v',
+			pstate & PSR_D_BIT ? 'D' : 'd',
+			pstate & PSR_A_BIT ? 'A' : 'a',
+			pstate & PSR_I_BIT ? 'I' : 'i',
+			pstate & PSR_F_BIT ? 'F' : 'f',
+			pstate & PSR_PAN_BIT ? '+' : '-',
+			pstate & PSR_UAO_BIT ? '+' : '-',
+			pstate & PSR_TCO_BIT ? '+' : '-',
+			pstate & PSR_DIT_BIT ? '+' : '-',
+			pstate & PSR_SSBS_BIT ? '+' : '-',
+			btype_str);
+	}
+}
+
 void __show_regs(struct pt_regs *regs)
 {
 	int i, top_reg;
@@ -186,39 +215,47 @@ void __show_regs(struct pt_regs *regs)
 	}
 
 	show_regs_print_info(KERN_DEFAULT);
-	print_symbol("PC is at %s\n", instruction_pointer(regs));
-	print_symbol("LR is at %s\n", lr);
-	printk("pc : [<%016llx>] lr : [<%016llx>] pstate: %08llx\n",
-	       regs->pc, lr, regs->pstate);
+	print_pstate(regs);
+
+	if (!user_mode(regs)) {
+		printk("pc : %pS\n", (void *)regs->pc);
+		printk("lr : %pS\n", (void *)ptrauth_strip_kernel_insn_pac(lr));
+	} else {
+		printk("pc : %016llx\n", regs->pc);
+		printk("lr : %016llx\n", lr);
+	}
+
 	printk("sp : %016llx\n", sp);
 
+	if (system_uses_irq_prio_masking())
+		printk("pmr: %08x\n", regs->pmr);
+
 	i = top_reg;
 
 	while (i >= 0) {
-		printk("x%-2d: %016llx ", i, regs->regs[i]);
-		i--;
+		printk("x%-2d: %016llx", i, regs->regs[i]);
 
-		if (i % 2 == 0) {
-			pr_cont("x%-2d: %016llx ", i, regs->regs[i]);
-			i--;
-		}
+		while (i-- % 3)
+			pr_cont(" x%-2d: %016llx", i, regs->regs[i]);
 
 		pr_cont("\n");
 	}
 }
 
-void show_regs(struct pt_regs * regs)
+void show_regs(struct pt_regs *regs)
 {
 	__show_regs(regs);
-	dump_backtrace(regs, NULL);
+	dump_backtrace(regs, NULL, KERN_DEFAULT);
 }
 
 static void tls_thread_flush(void)
 {
 	write_sysreg(0, tpidr_el0);
+	if (system_supports_tpidr2())
+		write_sysreg_s(0, SYS_TPIDR2_EL0);
 
 	if (is_compat_task()) {
-		current->thread.tp_value = 0;
+		current->thread.uw.tp_value = 0;
 
 		/*
 		 * We need to ensure ordering between the shadow state and the
@@ -230,35 +267,168 @@ static void tls_thread_flush(void)
 	}
 }
 
+static void flush_tagged_addr_state(void)
+{
+	if (IS_ENABLED(CONFIG_ARM64_TAGGED_ADDR_ABI))
+		clear_thread_flag(TIF_TAGGED_ADDR);
+}
+
+static void flush_poe(void)
+{
+	if (!system_supports_poe())
+		return;
+
+	write_sysreg_s(POR_EL0_INIT, SYS_POR_EL0);
+}
+
+#ifdef CONFIG_ARM64_GCS
+
+static void flush_gcs(void)
+{
+	if (!system_supports_gcs())
+		return;
+
+	current->thread.gcspr_el0 = 0;
+	current->thread.gcs_base = 0;
+	current->thread.gcs_size = 0;
+	current->thread.gcs_el0_mode = 0;
+	write_sysreg_s(GCSCRE0_EL1_nTR, SYS_GCSCRE0_EL1);
+	write_sysreg_s(0, SYS_GCSPR_EL0);
+}
+
+static int copy_thread_gcs(struct task_struct *p,
+			   const struct kernel_clone_args *args)
+{
+	unsigned long gcs;
+
+	if (!system_supports_gcs())
+		return 0;
+
+	p->thread.gcs_base = 0;
+	p->thread.gcs_size = 0;
+
+	p->thread.gcs_el0_mode = current->thread.gcs_el0_mode;
+	p->thread.gcs_el0_locked = current->thread.gcs_el0_locked;
+
+	gcs = gcs_alloc_thread_stack(p, args);
+	if (IS_ERR_VALUE(gcs))
+		return PTR_ERR((void *)gcs);
+
+	return 0;
+}
+
+#else
+
+static void flush_gcs(void) { }
+static int copy_thread_gcs(struct task_struct *p,
+			   const struct kernel_clone_args *args)
+{
+	return 0;
+}
+
+#endif
+
 void flush_thread(void)
 {
 	fpsimd_flush_thread();
 	tls_thread_flush();
 	flush_ptrace_hw_breakpoint(current);
+	flush_tagged_addr_state();
+	flush_poe();
+	flush_gcs();
 }
 
-void release_thread(struct task_struct *dead_task)
+void arch_release_task_struct(struct task_struct *tsk)
 {
+	fpsimd_release_task(tsk);
 }
 
 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 {
-	if (current->mm)
-		fpsimd_preserve_current_state();
+	/*
+	 * The current/src task's FPSIMD state may or may not be live, and may
+	 * have been altered by ptrace after entry to the kernel. Save the
+	 * effective FPSIMD state so that this will be copied into dst.
+	 */
+	fpsimd_save_and_flush_current_state();
+	fpsimd_sync_from_effective_state(src);
+
 	*dst = *src;
+
+	/*
+	 * Drop stale reference to src's sve_state and convert dst to
+	 * non-streaming FPSIMD mode.
+	 */
+	dst->thread.fp_type = FP_STATE_FPSIMD;
+	dst->thread.sve_state = NULL;
+	clear_tsk_thread_flag(dst, TIF_SVE);
+	task_smstop_sm(dst);
+
+	/*
+	 * Drop stale reference to src's sme_state and ensure dst has ZA
+	 * disabled.
+	 *
+	 * When necessary, ZA will be inherited later in copy_thread_za().
+	 */
+	dst->thread.sme_state = NULL;
+	clear_tsk_thread_flag(dst, TIF_SME);
+	dst->thread.svcr &= ~SVCR_ZA_MASK;
+
+	/* clear any pending asynchronous tag fault raised by the parent */
+	clear_tsk_thread_flag(dst, TIF_MTE_ASYNC_FAULT);
+
+	return 0;
+}
+
+static int copy_thread_za(struct task_struct *dst, struct task_struct *src)
+{
+	if (!thread_za_enabled(&src->thread))
+		return 0;
+
+	dst->thread.sve_state = kzalloc(sve_state_size(src),
+					GFP_KERNEL);
+	if (!dst->thread.sve_state)
+		return -ENOMEM;
+
+	dst->thread.sme_state = kmemdup(src->thread.sme_state,
+					sme_state_size(src),
+					GFP_KERNEL);
+	if (!dst->thread.sme_state) {
+		kfree(dst->thread.sve_state);
+		dst->thread.sve_state = NULL;
+		return -ENOMEM;
+	}
+
+	set_tsk_thread_flag(dst, TIF_SME);
+	dst->thread.svcr |= SVCR_ZA_MASK;
+
 	return 0;
 }
 
 asmlinkage void ret_from_fork(void) asm("ret_from_fork");
 
-int copy_thread(unsigned long clone_flags, unsigned long stack_start,
-		unsigned long stk_sz, struct task_struct *p)
+int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
 {
+	u64 clone_flags = args->flags;
+	unsigned long stack_start = args->stack;
+	unsigned long tls = args->tls;
 	struct pt_regs *childregs = task_pt_regs(p);
+	int ret;
 
 	memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context));
 
-	if (likely(!(p->flags & PF_KTHREAD))) {
+	/*
+	 * In case p was allocated the same task_struct pointer as some
+	 * other recently-exited task, make sure p is disassociated from
+	 * any cpu that may have run that now-exited task recently.
+	 * Otherwise we could erroneously skip reloading the FPSIMD
+	 * registers for p.
+	 */
+	fpsimd_flush_task_state(p);
+
+	ptrauth_thread_init_kernel(p);
+
+	if (likely(!args->fn)) {
 		*childregs = *current_pt_regs();
 		childregs->regs[0] = 0;
 
@@ -268,6 +438,9 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start,
 		 */
 		*task_user_tls(p) = read_sysreg(tpidr_el0);
 
+		if (system_supports_poe())
+			p->thread.por_el0 = read_sysreg_s(SYS_POR_EL0);
+
 		if (stack_start) {
 			if (is_compat_thread(task_thread_info(p)))
 				childregs->compat_sp = stack_start;
@@ -276,22 +449,68 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start,
 		}
 
 		/*
-		 * If a TLS pointer was passed to clone (4th argument), use it
-		 * for the new thread.
+		 * Due to the AAPCS64 "ZA lazy saving scheme", PSTATE.ZA and
+		 * TPIDR2 need to be manipulated as a pair, and either both
+		 * need to be inherited or both need to be reset.
+		 *
+		 * Within a process, child threads must not inherit their
+		 * parent's TPIDR2 value or they may clobber their parent's
+		 * stack at some later point.
+		 *
+		 * When a process is fork()'d, the child must inherit ZA and
+		 * TPIDR2 from its parent in case there was dormant ZA state.
+		 *
+		 * Use CLONE_VM to determine when the child will share the
+		 * address space with the parent, and cannot safely inherit the
+		 * state.
+		 */
+		if (system_supports_sme()) {
+			if (!(clone_flags & CLONE_VM)) {
+				p->thread.tpidr2_el0 = read_sysreg_s(SYS_TPIDR2_EL0);
+				ret = copy_thread_za(p, current);
+				if (ret)
+					return ret;
+			} else {
+				p->thread.tpidr2_el0 = 0;
+				WARN_ON_ONCE(p->thread.svcr & SVCR_ZA_MASK);
+			}
+		}
+
+		/*
+		 * If a TLS pointer was passed to clone, use it for the new
+		 * thread.
 		 */
 		if (clone_flags & CLONE_SETTLS)
-			p->thread.tp_value = childregs->regs[3];
+			p->thread.uw.tp_value = tls;
+
+		ret = copy_thread_gcs(p, args);
+		if (ret != 0)
+			return ret;
 	} else {
+		/*
+		 * A kthread has no context to ERET to, so ensure any buggy
+		 * ERET is treated as an illegal exception return.
+		 *
+		 * When a user task is created from a kthread, childregs will
+		 * be initialized by start_thread() or start_compat_thread().
+		 */
 		memset(childregs, 0, sizeof(struct pt_regs));
-		childregs->pstate = PSR_MODE_EL1h;
-		if (IS_ENABLED(CONFIG_ARM64_UAO) &&
-		    cpus_have_const_cap(ARM64_HAS_UAO))
-			childregs->pstate |= PSR_UAO_BIT;
-		p->thread.cpu_context.x19 = stack_start;
-		p->thread.cpu_context.x20 = stk_sz;
+		childregs->pstate = PSR_MODE_EL1h | PSR_IL_BIT;
+		childregs->stackframe.type = FRAME_META_TYPE_FINAL;
+
+		p->thread.cpu_context.x19 = (unsigned long)args->fn;
+		p->thread.cpu_context.x20 = (unsigned long)args->fn_arg;
+
+		if (system_supports_poe())
+			p->thread.por_el0 = POR_EL0_INIT;
 	}
 	p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
 	p->thread.cpu_context.sp = (unsigned long)childregs;
+	/*
+	 * For the benefit of the unwinder, set up childregs->stackframe
+	 * as the final frame for the new task.
+	 */
+	p->thread.cpu_context.fp = (unsigned long)&childregs->stackframe;
 
 	ptrace_hw_copy_thread(p);
 
@@ -301,31 +520,45 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start,
 void tls_preserve_current_state(void)
 {
 	*task_user_tls(current) = read_sysreg(tpidr_el0);
+	if (system_supports_tpidr2() && !is_compat_task())
+		current->thread.tpidr2_el0 = read_sysreg_s(SYS_TPIDR2_EL0);
 }
 
 static void tls_thread_switch(struct task_struct *next)
 {
-	unsigned long tpidr, tpidrro;
-
 	tls_preserve_current_state();
 
-	tpidr = *task_user_tls(next);
-	tpidrro = is_compat_thread(task_thread_info(next)) ?
-		  next->thread.tp_value : 0;
+	if (is_compat_thread(task_thread_info(next)))
+		write_sysreg(next->thread.uw.tp_value, tpidrro_el0);
+	else
+		write_sysreg(0, tpidrro_el0);
 
-	write_sysreg(tpidr, tpidr_el0);
-	write_sysreg(tpidrro, tpidrro_el0);
+	write_sysreg(*task_user_tls(next), tpidr_el0);
+	if (system_supports_tpidr2())
+		write_sysreg_s(next->thread.tpidr2_el0, SYS_TPIDR2_EL0);
 }
 
-/* Restore the UAO state depending on next's addr_limit */
-void uao_thread_switch(struct task_struct *next)
+/*
+ * Force SSBS state on context-switch, since it may be lost after migrating
+ * from a CPU which treats the bit as RES0 in a heterogeneous system.
+ */
+static void ssbs_thread_switch(struct task_struct *next)
 {
-	if (IS_ENABLED(CONFIG_ARM64_UAO)) {
-		if (task_thread_info(next)->addr_limit == KERNEL_DS)
-			asm(ALTERNATIVE("nop", SET_PSTATE_UAO(1), ARM64_HAS_UAO));
-		else
-			asm(ALTERNATIVE("nop", SET_PSTATE_UAO(0), ARM64_HAS_UAO));
-	}
+	/*
+	 * Nothing to do for kernel threads, but 'regs' may be junk
+	 * (e.g. idle task) so check the flags and bail early.
+	 */
+	if (unlikely(next->flags & PF_KTHREAD))
+		return;
+
+	/*
+	 * If all CPUs implement the SSBS extension, then we just need to
+	 * context-switch the PSTATE field.
+	 */
+	if (alternative_has_cap_unlikely(ARM64_SSBS))
+		return;
+
+	spectre_v4_enable_task_mitigation(next);
 }
 
 /*
@@ -342,10 +575,134 @@ static void entry_task_switch(struct task_struct *next)
 	__this_cpu_write(__entry_task, next);
 }
 
+#ifdef CONFIG_ARM64_GCS
+
+void gcs_preserve_current_state(void)
+{
+	current->thread.gcspr_el0 = read_sysreg_s(SYS_GCSPR_EL0);
+}
+
+static void gcs_thread_switch(struct task_struct *next)
+{
+	if (!system_supports_gcs())
+		return;
+
+	/* GCSPR_EL0 is always readable */
+	gcs_preserve_current_state();
+	write_sysreg_s(next->thread.gcspr_el0, SYS_GCSPR_EL0);
+
+	if (current->thread.gcs_el0_mode != next->thread.gcs_el0_mode)
+		gcs_set_el0_mode(next);
+
+	/*
+	 * Ensure that GCS memory effects of the 'prev' thread are
+	 * ordered before other memory accesses with release semantics
+	 * (or preceded by a DMB) on the current PE. In addition, any
+	 * memory accesses with acquire semantics (or succeeded by a
+	 * DMB) are ordered before GCS memory effects of the 'next'
+	 * thread. This will ensure that the GCS memory effects are
+	 * visible to other PEs in case of migration.
+	 */
+	if (task_gcs_el0_enabled(current) || task_gcs_el0_enabled(next))
+		gcsb_dsync();
+}
+
+#else
+
+static void gcs_thread_switch(struct task_struct *next)
+{
+}
+
+#endif
+
+/*
+ * Handle sysreg updates for ARM erratum 1418040 which affects the 32bit view of
+ * CNTVCT, various other errata which require trapping all CNTVCT{,_EL0}
+ * accesses and prctl(PR_SET_TSC). Ensure access is disabled iff a workaround is
+ * required or PR_TSC_SIGSEGV is set.
+ */
+static void update_cntkctl_el1(struct task_struct *next)
+{
+	struct thread_info *ti = task_thread_info(next);
+
+	if (test_ti_thread_flag(ti, TIF_TSC_SIGSEGV) ||
+	    has_erratum_handler(read_cntvct_el0) ||
+	    (IS_ENABLED(CONFIG_ARM64_ERRATUM_1418040) &&
+	     this_cpu_has_cap(ARM64_WORKAROUND_1418040) &&
+	     is_compat_thread(ti)))
+		sysreg_clear_set(cntkctl_el1, ARCH_TIMER_USR_VCT_ACCESS_EN, 0);
+	else
+		sysreg_clear_set(cntkctl_el1, 0, ARCH_TIMER_USR_VCT_ACCESS_EN);
+}
+
+static void cntkctl_thread_switch(struct task_struct *prev,
+				  struct task_struct *next)
+{
+	if ((read_ti_thread_flags(task_thread_info(prev)) &
+	     (_TIF_32BIT | _TIF_TSC_SIGSEGV)) !=
+	    (read_ti_thread_flags(task_thread_info(next)) &
+	     (_TIF_32BIT | _TIF_TSC_SIGSEGV)))
+		update_cntkctl_el1(next);
+}
+
+static int do_set_tsc_mode(unsigned int val)
+{
+	bool tsc_sigsegv;
+
+	if (val == PR_TSC_SIGSEGV)
+		tsc_sigsegv = true;
+	else if (val == PR_TSC_ENABLE)
+		tsc_sigsegv = false;
+	else
+		return -EINVAL;
+
+	preempt_disable();
+	update_thread_flag(TIF_TSC_SIGSEGV, tsc_sigsegv);
+	update_cntkctl_el1(current);
+	preempt_enable();
+
+	return 0;
+}
+
+static void permission_overlay_switch(struct task_struct *next)
+{
+	if (!system_supports_poe())
+		return;
+
+	current->thread.por_el0 = read_sysreg_s(SYS_POR_EL0);
+	if (current->thread.por_el0 != next->thread.por_el0) {
+		write_sysreg_s(next->thread.por_el0, SYS_POR_EL0);
+		/*
+		 * No ISB required as we can tolerate spurious Overlay faults -
+		 * the fault handler will check again based on the new value
+		 * of POR_EL0.
+		 */
+	}
+}
+
+/*
+ * __switch_to() checks current->thread.sctlr_user as an optimisation. Therefore
+ * this function must be called with preemption disabled and the update to
+ * sctlr_user must be made in the same preemption disabled block so that
+ * __switch_to() does not see the variable update before the SCTLR_EL1 one.
+ */
+void update_sctlr_el1(u64 sctlr)
+{
+	/*
+	 * EnIA must not be cleared while in the kernel as this is necessary for
+	 * in-kernel PAC. It will be cleared on kernel exit if needed.
+	 */
+	sysreg_clear_set(sctlr_el1, SCTLR_USER_MASK & ~SCTLR_ELx_ENIA, sctlr);
+
+	/* ISB required for the kernel uaccess routines when setting TCF0. */
+	isb();
+}
+
 /*
  * Thread switching.
  */
-__notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev,
+__notrace_funcgraph __sched
+struct task_struct *__switch_to(struct task_struct *prev,
 				struct task_struct *next)
 {
 	struct task_struct *last;
@@ -355,65 +712,260 @@ __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev,
 	hw_breakpoint_thread_switch(next);
 	contextidr_thread_switch(next);
 	entry_task_switch(next);
-	uao_thread_switch(next);
+	ssbs_thread_switch(next);
+	cntkctl_thread_switch(prev, next);
+	ptrauth_thread_switch_user(next);
+	permission_overlay_switch(next);
+	gcs_thread_switch(next);
 
 	/*
-	 * Complete any pending TLB or cache maintenance on this CPU in case
-	 * the thread migrates to a different CPU.
+	 * Complete any pending TLB or cache maintenance on this CPU in case the
+	 * thread migrates to a different CPU. This full barrier is also
+	 * required by the membarrier system call. Additionally it makes any
+	 * in-progress pgtable writes visible to the table walker; See
+	 * emit_pte_barriers().
 	 */
 	dsb(ish);
 
+	/*
+	 * MTE thread switching must happen after the DSB above to ensure that
+	 * any asynchronous tag check faults have been logged in the TFSR*_EL1
+	 * registers.
+	 */
+	mte_thread_switch(next);
+	/* avoid expensive SCTLR_EL1 accesses if no change */
+	if (prev->thread.sctlr_user != next->thread.sctlr_user)
+		update_sctlr_el1(next->thread.sctlr_user);
+
 	/* the actual thread switch */
 	last = cpu_switch_to(prev, next);
 
 	return last;
 }
 
-unsigned long get_wchan(struct task_struct *p)
+struct wchan_info {
+	unsigned long	pc;
+	int		count;
+};
+
+static bool get_wchan_cb(void *arg, unsigned long pc)
 {
-	struct stackframe frame;
-	unsigned long stack_page, ret = 0;
-	int count = 0;
-	if (!p || p == current || p->state == TASK_RUNNING)
-		return 0;
+	struct wchan_info *wchan_info = arg;
 
-	stack_page = (unsigned long)try_get_task_stack(p);
-	if (!stack_page)
+	if (!in_sched_functions(pc)) {
+		wchan_info->pc = pc;
+		return false;
+	}
+	return wchan_info->count++ < 16;
+}
+
+unsigned long __get_wchan(struct task_struct *p)
+{
+	struct wchan_info wchan_info = {
+		.pc = 0,
+		.count = 0,
+	};
+
+	if (!try_get_task_stack(p))
 		return 0;
 
-	frame.fp = thread_saved_fp(p);
-	frame.sp = thread_saved_sp(p);
-	frame.pc = thread_saved_pc(p);
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	frame.graph = p->curr_ret_stack;
-#endif
-	do {
-		if (frame.sp < stack_page ||
-		    frame.sp >= stack_page + THREAD_SIZE ||
-		    unwind_frame(p, &frame))
-			goto out;
-		if (!in_sched_functions(frame.pc)) {
-			ret = frame.pc;
-			goto out;
-		}
-	} while (count ++ < 16);
+	arch_stack_walk(get_wchan_cb, &wchan_info, p, NULL);
 
-out:
 	put_task_stack(p);
-	return ret;
+
+	return wchan_info.pc;
 }
 
 unsigned long arch_align_stack(unsigned long sp)
 {
 	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
-		sp -= get_random_int() & ~PAGE_MASK;
+		sp -= get_random_u32_below(PAGE_SIZE);
 	return sp & ~0xf;
 }
 
-unsigned long arch_randomize_brk(struct mm_struct *mm)
+#ifdef CONFIG_COMPAT
+int compat_elf_check_arch(const struct elf32_hdr *hdr)
 {
+	if (!system_supports_32bit_el0())
+		return false;
+
+	if ((hdr)->e_machine != EM_ARM)
+		return false;
+
+	if (!((hdr)->e_flags & EF_ARM_EABI_MASK))
+		return false;
+
+	/*
+	 * Prevent execve() of a 32-bit program from a deadline task
+	 * if the restricted affinity mask would be inadmissible on an
+	 * asymmetric system.
+	 */
+	return !static_branch_unlikely(&arm64_mismatched_32bit_el0) ||
+	       !dl_task_check_affinity(current, system_32bit_el0_cpumask());
+}
+#endif
+
+/*
+ * Called from setup_new_exec() after (COMPAT_)SET_PERSONALITY.
+ */
+void arch_setup_new_exec(void)
+{
+	unsigned long mmflags = 0;
+
+	if (is_compat_task()) {
+		mmflags = MMCF_AARCH32;
+
+		/*
+		 * Restrict the CPU affinity mask for a 32-bit task so that
+		 * it contains only 32-bit-capable CPUs.
+		 *
+		 * From the perspective of the task, this looks similar to
+		 * what would happen if the 64-bit-only CPUs were hot-unplugged
+		 * at the point of execve(), although we try a bit harder to
+		 * honour the cpuset hierarchy.
+		 */
+		if (static_branch_unlikely(&arm64_mismatched_32bit_el0))
+			force_compatible_cpus_allowed_ptr(current);
+	} else if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) {
+		relax_compatible_cpus_allowed_ptr(current);
+	}
+
+	current->mm->context.flags = mmflags;
+	ptrauth_thread_init_user();
+	mte_thread_init_user();
+	do_set_tsc_mode(PR_TSC_ENABLE);
+
+	if (task_spec_ssb_noexec(current)) {
+		arch_prctl_spec_ctrl_set(current, PR_SPEC_STORE_BYPASS,
+					 PR_SPEC_ENABLE);
+	}
+}
+
+#ifdef CONFIG_ARM64_TAGGED_ADDR_ABI
+/*
+ * Control the relaxed ABI allowing tagged user addresses into the kernel.
+ */
+static unsigned int tagged_addr_disabled;
+
+long set_tagged_addr_ctrl(struct task_struct *task, unsigned long arg)
+{
+	unsigned long valid_mask = PR_TAGGED_ADDR_ENABLE;
+	struct thread_info *ti = task_thread_info(task);
+
+	if (is_compat_thread(ti))
+		return -EINVAL;
+
+	if (system_supports_mte()) {
+		valid_mask |= PR_MTE_TCF_SYNC | PR_MTE_TCF_ASYNC \
+			| PR_MTE_TAG_MASK;
+
+		if (cpus_have_cap(ARM64_MTE_STORE_ONLY))
+			valid_mask |= PR_MTE_STORE_ONLY;
+	}
+
+	if (arg & ~valid_mask)
+		return -EINVAL;
+
+	/*
+	 * Do not allow the enabling of the tagged address ABI if globally
+	 * disabled via sysctl abi.tagged_addr_disabled.
+	 */
+	if (arg & PR_TAGGED_ADDR_ENABLE && tagged_addr_disabled)
+		return -EINVAL;
+
+	if (set_mte_ctrl(task, arg) != 0)
+		return -EINVAL;
+
+	update_ti_thread_flag(ti, TIF_TAGGED_ADDR, arg & PR_TAGGED_ADDR_ENABLE);
+
+	return 0;
+}
+
+long get_tagged_addr_ctrl(struct task_struct *task)
+{
+	long ret = 0;
+	struct thread_info *ti = task_thread_info(task);
+
+	if (is_compat_thread(ti))
+		return -EINVAL;
+
+	if (test_ti_thread_flag(ti, TIF_TAGGED_ADDR))
+		ret = PR_TAGGED_ADDR_ENABLE;
+
+	ret |= get_mte_ctrl(task);
+
+	return ret;
+}
+
+/*
+ * Global sysctl to disable the tagged user addresses support. This control
+ * only prevents the tagged address ABI enabling via prctl() and does not
+ * disable it for tasks that already opted in to the relaxed ABI.
+ */
+
+static const struct ctl_table tagged_addr_sysctl_table[] = {
+	{
+		.procname	= "tagged_addr_disabled",
+		.mode		= 0644,
+		.data		= &tagged_addr_disabled,
+		.maxlen		= sizeof(int),
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+};
+
+static int __init tagged_addr_init(void)
+{
+	if (!register_sysctl("abi", tagged_addr_sysctl_table))
+		return -EINVAL;
+	return 0;
+}
+
+core_initcall(tagged_addr_init);
+#endif	/* CONFIG_ARM64_TAGGED_ADDR_ABI */
+
+#ifdef CONFIG_BINFMT_ELF
+int arch_elf_adjust_prot(int prot, const struct arch_elf_state *state,
+			 bool has_interp, bool is_interp)
+{
+	/*
+	 * For dynamically linked executables the interpreter is
+	 * responsible for setting PROT_BTI on everything except
+	 * itself.
+	 */
+	if (is_interp != has_interp)
+		return prot;
+
+	if (!(state->flags & ARM64_ELF_BTI))
+		return prot;
+
+	if (prot & PROT_EXEC)
+		prot |= PROT_BTI;
+
+	return prot;
+}
+#endif
+
+int get_tsc_mode(unsigned long adr)
+{
+	unsigned int val;
+
 	if (is_compat_task())
-		return randomize_page(mm->brk, SZ_32M);
+		return -EINVAL;
+
+	if (test_thread_flag(TIF_TSC_SIGSEGV))
+		val = PR_TSC_SIGSEGV;
 	else
-		return randomize_page(mm->brk, SZ_1G);
+		val = PR_TSC_ENABLE;
+
+	return put_user(val, (unsigned int __user *)adr);
+}
+
+int set_tsc_mode(unsigned int val)
+{
+	if (is_compat_task())
+		return -EINVAL;
+
+	return do_set_tsc_mode(val);
 }