Merge tag 'kvm-s390-master-5.7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into kvm-master

KVM: s390: Fix for 5.7 and maintainer update

- Silence false positive lockdep warning
- add Claudio as reviewer

1 files changed, 25 insertions, 7 deletions

diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index e05e6dd67ae6..438a9befce41 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -279,24 +279,42 @@ void __init record_spr_defaults(void)
  * device-tree is not accessible via normal means at this point.
  */
 
-void __init early_setup(unsigned long dt_ptr)
+void __init __nostackprotector early_setup(unsigned long dt_ptr)
 {
 	static __initdata struct paca_struct boot_paca;
 
 	/* -------- printk is _NOT_ safe to use here ! ------- */
 
-	/* Try new device tree based feature discovery ... */
-	if (!dt_cpu_ftrs_init(__va(dt_ptr)))
-		/* Otherwise use the old style CPU table */
-		identify_cpu(0, mfspr(SPRN_PVR));
-
-	/* Assume we're on cpu 0 for now. Don't write to the paca yet! */
+	/*
+	 * Assume we're on cpu 0 for now.
+	 *
+	 * We need to load a PACA very early for a few reasons.
+	 *
+	 * The stack protector canary is stored in the paca, so as soon as we
+	 * call any stack protected code we need r13 pointing somewhere valid.
+	 *
+	 * If we are using kcov it will call in_task() in its instrumentation,
+	 * which relies on the current task from the PACA.
+	 *
+	 * dt_cpu_ftrs_init() calls into generic OF/fdt code, as well as
+	 * printk(), which can trigger both stack protector and kcov.
+	 *
+	 * percpu variables and spin locks also use the paca.
+	 *
+	 * So set up a temporary paca. It will be replaced below once we know
+	 * what CPU we are on.
+	 */
 	initialise_paca(&boot_paca, 0);
 	setup_paca(&boot_paca);
 	fixup_boot_paca();
 
 	/* -------- printk is now safe to use ------- */
 
+	/* Try new device tree based feature discovery ... */
+	if (!dt_cpu_ftrs_init(__va(dt_ptr)))
+		/* Otherwise use the old style CPU table */
+		identify_cpu(0, mfspr(SPRN_PVR));
+
 	/* Enable early debugging if any specified (see udbg.h) */
 	udbg_early_init();