1 files changed, 57 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/entry-common.h b/arch/arm64/include/asm/entry-common.h
new file mode 100644
index 000000000000..cab8cd78f693
--- /dev/null
+++ b/arch/arm64/include/asm/entry-common.h
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _ASM_ARM64_ENTRY_COMMON_H
+#define _ASM_ARM64_ENTRY_COMMON_H
+
+#include <linux/thread_info.h>
+
+#include <asm/cpufeature.h>
+#include <asm/daifflags.h>
+#include <asm/fpsimd.h>
+#include <asm/mte.h>
+#include <asm/stacktrace.h>
+
+#define ARCH_EXIT_TO_USER_MODE_WORK (_TIF_MTE_ASYNC_FAULT | _TIF_FOREIGN_FPSTATE)
+
+static __always_inline void arch_exit_to_user_mode_work(struct pt_regs *regs,
+							unsigned long ti_work)
+{
+	if (ti_work & _TIF_MTE_ASYNC_FAULT) {
+		clear_thread_flag(TIF_MTE_ASYNC_FAULT);
+		send_sig_fault(SIGSEGV, SEGV_MTEAERR, (void __user *)NULL, current);
+	}
+
+	if (ti_work & _TIF_FOREIGN_FPSTATE)
+		fpsimd_restore_current_state();
+}
+
+#define arch_exit_to_user_mode_work arch_exit_to_user_mode_work
+
+static inline bool arch_irqentry_exit_need_resched(void)
+{
+	/*
+	 * DAIF.DA are cleared at the start of IRQ/FIQ handling, and when GIC
+	 * priority masking is used the GIC irqchip driver will clear DAIF.IF
+	 * using gic_arch_enable_irqs() for normal IRQs. If anything is set in
+	 * DAIF we must have handled an NMI, so skip preemption.
+	 */
+	if (system_uses_irq_prio_masking() && read_sysreg(daif))
+		return false;
+
+	/*
+	 * Preempting a task from an IRQ means we leave copies of PSTATE
+	 * on the stack. cpufeature's enable calls may modify PSTATE, but
+	 * resuming one of these preempted tasks would undo those changes.
+	 *
+	 * Only allow a task to be preempted once cpufeatures have been
+	 * enabled.
+	 */
+	if (!system_capabilities_finalized())
+		return false;
+
+	return true;
+}
+
+#define arch_irqentry_exit_need_resched arch_irqentry_exit_need_resched
+
+#endif /* _ASM_ARM64_ENTRY_COMMON_H */