diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index b27dac4a9c0f..6f9ad2d2bb40 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -50,10 +50,6 @@
 	msr	daif, \flags
 	.endm
 
-	.macro	enable_dbg
-	msr	daifclr, #8
-	.endm
-
 	.macro	disable_step_tsk, flgs, tmp
 	tbz	\flgs, #TIF_SINGLESTEP, 9990f
 	mrs	\tmp, mdscr_el1
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 65a052bf741f..a096e2451044 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -298,8 +298,15 @@ void __init __no_sanitize_address setup_arch(char **cmdline_p)
 	dynamic_scs_init();
 
 	/*
-	 * Unmask SError as soon as possible after initializing earlycon so
-	 * that we can report any SErrors immediately.
+	 * The primary CPU enters the kernel with all DAIF exceptions masked.
+	 *
+	 * We must unmask Debug and SError before preemption or scheduling is
+	 * possible to ensure that these are consistently unmasked across
+	 * threads, and we want to unmask SError as soon as possible after
+	 * initializing earlycon so that we can report any SErrors immediately.
+	 *
+	 * IRQ and FIQ will be unmasked after the root irqchip has been
+	 * detected and initialized.
 	 */
 	local_daif_restore(DAIF_PROCCTX_NOIRQ);
 
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 4ced34f62dab..31c8b3094dd7 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -264,6 +264,13 @@ asmlinkage notrace void secondary_start_kernel(void)
 	set_cpu_online(cpu, true);
 	complete(&cpu_running);
 
+	/*
+	 * Secondary CPUs enter the kernel with all DAIF exceptions masked.
+	 *
+	 * As with setup_arch() we must unmask Debug and SError exceptions, and
+	 * as the root irqchip has already been detected and initialized we can
+	 * unmask IRQ and FIQ at the same time.
+	 */
 	local_daif_restore(DAIF_PROCCTX);
 
 	/*
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index 9d40f3ffd8d2..f4bc6c5bac06 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -135,14 +135,6 @@ SYM_FUNC_START(cpu_do_resume)
 
 	msr	tcr_el1, x8
 	msr	vbar_el1, x9
-
-	/*
-	 * __cpu_setup() cleared MDSCR_EL1.MDE and friends, before unmasking
-	 * debug exceptions. By restoring MDSCR_EL1 here, we may take a debug
-	 * exception. Mask them until local_daif_restore() in cpu_suspend()
-	 * resets them.
-	 */
-	disable_daif
 	msr	mdscr_el1, x10
 
 	msr	sctlr_el1, x12
@@ -466,8 +458,6 @@ SYM_FUNC_START(__cpu_setup)
 	msr	cpacr_el1, xzr			// Reset cpacr_el1
 	mov	x1, #1 << 12			// Reset mdscr_el1 and disable
 	msr	mdscr_el1, x1			// access to the DCC from EL0
-	isb					// Unmask debug exceptions now,
-	enable_dbg				// since this is per-cpu
 	reset_pmuserenr_el0 x1			// Disable PMU access from EL0
 	reset_amuserenr_el0 x1			// Disable AMU access from EL0