arm64: explicitly mask all exceptions

There are a few places where we want to mask all exceptions. Today we
do this in a piecemeal fashion, typically we expect the caller to
have masked irqs and the arch code masks debug exceptions, ignoring
serror which is probably masked.

Make it clear that 'mask all exceptions' is the intention by adding
helpers to do exactly that.

This will let us unmask SError without having to add 'oh and SError'
to these paths.

Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

5 files changed, 14 insertions, 14 deletions

diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
index 095d3c170f5d..3009b8b80f08 100644
--- a/arch/arm64/kernel/hibernate.c
+++ b/arch/arm64/kernel/hibernate.c
@@ -27,6 +27,7 @@
 #include <asm/barrier.h>
 #include <asm/cacheflush.h>
 #include <asm/cputype.h>
+#include <asm/daifflags.h>
 #include <asm/irqflags.h>
 #include <asm/kexec.h>
 #include <asm/memory.h>
@@ -285,7 +286,7 @@ int swsusp_arch_suspend(void)
 		return -EBUSY;
 	}
 
-	local_dbg_save(flags);
+	flags = local_daif_save();
 
 	if (__cpu_suspend_enter(&state)) {
 		/* make the crash dump kernel image visible/saveable */
@@ -315,7 +316,7 @@ int swsusp_arch_suspend(void)
 		__cpu_suspend_exit();
 	}
 
-	local_dbg_restore(flags);
+	local_daif_restore(flags);
 
 	return ret;
 }
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index 11121f608eb5..f76ea92dff91 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -18,6 +18,7 @@
 
 #include <asm/cacheflush.h>
 #include <asm/cpu_ops.h>
+#include <asm/daifflags.h>
 #include <asm/memory.h>
 #include <asm/mmu.h>
 #include <asm/mmu_context.h>
@@ -195,8 +196,7 @@ void machine_kexec(struct kimage *kimage)
 
 	pr_info("Bye!\n");
 
-	/* Disable all DAIF exceptions. */
-	asm volatile ("msr daifset, #0xf" : : : "memory");
+	local_daif_mask();
 
 	/*
 	 * cpu_soft_restart will shutdown the MMU, disable data caches, then
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 824561ef6b8a..c94f4a6515c4 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -47,6 +47,7 @@
 #include <asm/cpu.h>
 #include <asm/cputype.h>
 #include <asm/cpu_ops.h>
+#include <asm/daifflags.h>
 #include <asm/mmu_context.h>
 #include <asm/numa.h>
 #include <asm/pgtable.h>
@@ -370,10 +371,6 @@ void __cpu_die(unsigned int cpu)
 /*
  * Called from the idle thread for the CPU which has been shutdown.
  *
- * Note that we disable IRQs here, but do not re-enable them
- * before returning to the caller. This is also the behaviour
- * of the other hotplug-cpu capable cores, so presumably coming
- * out of idle fixes this.
  */
 void cpu_die(void)
 {
@@ -381,7 +378,7 @@ void cpu_die(void)
 
 	idle_task_exit();
 
-	local_irq_disable();
+	local_daif_mask();
 
 	/* Tell __cpu_die() that this CPU is now safe to dispose of */
 	(void)cpu_report_death();
@@ -839,7 +836,7 @@ static void ipi_cpu_stop(unsigned int cpu)
 {
 	set_cpu_online(cpu, false);
 
-	local_irq_disable();
+	local_daif_mask();
 
 	while (1)
 		cpu_relax();
diff --git a/arch/arm64/kernel/suspend.c b/arch/arm64/kernel/suspend.c
index 5794326975f8..9079dfe885fa 100644
--- a/arch/arm64/kernel/suspend.c
+++ b/arch/arm64/kernel/suspend.c
@@ -4,6 +4,7 @@
 #include <asm/alternative.h>
 #include <asm/cacheflush.h>
 #include <asm/cpufeature.h>
+#include <asm/daifflags.h>
 #include <asm/debug-monitors.h>
 #include <asm/exec.h>
 #include <asm/pgtable.h>
@@ -56,7 +57,7 @@ void notrace __cpu_suspend_exit(void)
 	/*
 	 * Restore HW breakpoint registers to sane values
 	 * before debug exceptions are possibly reenabled
-	 * through local_dbg_restore.
+	 * by cpu_suspend()s local_daif_restore() call.
 	 */
 	if (hw_breakpoint_restore)
 		hw_breakpoint_restore(cpu);
@@ -80,7 +81,7 @@ int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
 	 * updates to mdscr register (saved and restored along with
 	 * general purpose registers) from kernel debuggers.
 	 */
-	local_dbg_save(flags);
+	flags = local_daif_save();
 
 	/*
 	 * Function graph tracer state gets incosistent when the kernel
@@ -113,7 +114,7 @@ int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
 	 * restored, so from this point onwards, debugging is fully
 	 * renabled if it was enabled when core started shutdown.
 	 */
-	local_dbg_restore(flags);
+	local_daif_restore(flags);
 
 	return ret;
 }
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index afb6b19677dc..fa52aefaf7f2 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -38,6 +38,7 @@
 
 #include <asm/atomic.h>
 #include <asm/bug.h>
+#include <asm/daifflags.h>
 #include <asm/debug-monitors.h>
 #include <asm/esr.h>
 #include <asm/insn.h>
@@ -594,7 +595,7 @@ asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
 		esr_get_class_string(esr));
 
 	die("Oops - bad mode", regs, 0);
-	local_irq_disable();
+	local_daif_mask();
 	panic("bad mode");
 }