Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 fixes from Catalin Marinas:
 "Two left-over updates that could not go into -rc1 due to conflicts
  with other series:

   - Simplify checks in arch_kfence_init_pool() since
     force_pte_mapping() already takes BBML2-noabort (break-before-make
     Level 2 with no aborts generated) into account

   - Remove unneeded SVE/SME fallback preserve/store handling in the
     arm64 EFI. With the recent updates, the fallback path is only taken
     for EFI runtime calls from hardirq or NMI contexts. In practice,
     this only happens under panic/oops/emergency_restart() and no
     restoring of the user state expected.

     There's a corresponding lkdtm update to trigger a BUG() or panic()
     from hardirq context together with a fixup not to confuse
     clang/objtool about the control flow

  GCS (guarded control stacks) fix: flush the GCS locking state on exec,
  otherwise the new task will not be able to enable GCS (locked as
  disabled)"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  lkdtm/bugs: Do not confuse the clang/objtool with busy wait loop
  arm64/gcs: Flush the GCS locking state on exec
  arm64/efi: Remove unneeded SVE/SME fallback preserve/store handling
  lkdtm/bugs: Add cases for BUG and PANIC occurring in hardirq context
  arm64: mm: Simplify check in arch_kfence_init_pool()

1 files changed, 53 insertions, 0 deletions

diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c
index 376047beea3d..502059078b45 100644
--- a/drivers/misc/lkdtm/bugs.c
+++ b/drivers/misc/lkdtm/bugs.c
@@ -8,6 +8,7 @@
 #include "lkdtm.h"
 #include <linux/cpu.h>
 #include <linux/list.h>
+#include <linux/hrtimer.h>
 #include <linux/sched.h>
 #include <linux/sched/signal.h>
 #include <linux/sched/task_stack.h>
@@ -100,11 +101,61 @@ static void lkdtm_PANIC_STOP_IRQOFF(void)
 	stop_machine(panic_stop_irqoff_fn, &v, cpu_online_mask);
 }
 
+static bool wait_for_panic;
+
+static enum hrtimer_restart panic_in_hardirq(struct hrtimer *timer)
+{
+	panic("from hard IRQ context");
+
+	wait_for_panic = false;
+	return HRTIMER_NORESTART;
+}
+
+static void lkdtm_PANIC_IN_HARDIRQ(void)
+{
+	struct hrtimer timer;
+
+	wait_for_panic = true;
+	hrtimer_setup_on_stack(&timer, panic_in_hardirq,
+			       CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
+	hrtimer_start(&timer, us_to_ktime(100), HRTIMER_MODE_REL_HARD);
+
+	while (READ_ONCE(wait_for_panic))
+		cpu_relax();
+
+	hrtimer_cancel(&timer);
+}
+
 static void lkdtm_BUG(void)
 {
 	BUG();
 }
 
+static bool wait_for_bug;
+
+static enum hrtimer_restart bug_in_hardirq(struct hrtimer *timer)
+{
+	BUG();
+
+	wait_for_bug = false;
+	return HRTIMER_NORESTART;
+}
+
+static void lkdtm_BUG_IN_HARDIRQ(void)
+{
+	struct hrtimer timer;
+
+	wait_for_bug = true;
+	hrtimer_setup_on_stack(&timer, bug_in_hardirq,
+			       CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
+	hrtimer_start(&timer, us_to_ktime(100), HRTIMER_MODE_REL_HARD);
+
+	while (READ_ONCE(wait_for_bug))
+		cpu_relax();
+
+	hrtimer_cancel(&timer);
+}
+
 static int warn_counter;
 
 static void lkdtm_WARNING(void)
@@ -696,7 +747,9 @@ static noinline void lkdtm_CORRUPT_PAC(void)
 static struct crashtype crashtypes[] = {
 	CRASHTYPE(PANIC),
 	CRASHTYPE(PANIC_STOP_IRQOFF),
+	CRASHTYPE(PANIC_IN_HARDIRQ),
 	CRASHTYPE(BUG),
+	CRASHTYPE(BUG_IN_HARDIRQ),
 	CRASHTYPE(WARNING),
 	CRASHTYPE(WARNING_MESSAGE),
 	CRASHTYPE(EXCEPTION),