Re: [PATCH] ARM: mach-shmobile: Don't configure ARCH timer if PSCI is enabled

From: Oleksandr
Date: Thu Apr 18 2019 - 07:15:58 EST

On 18.04.19 12:32, Julien Grall wrote:

Hi Julien


diff --git a/arch/arm/mach-shmobile/setup-rcar-gen2.c b/arch/arm/mach-shmobile/setup-rcar-gen2.c
index eea60b2..bac4490 100644
--- a/arch/arm/mach-shmobile/setup-rcar-gen2.c
+++ b/arch/arm/mach-shmobile/setup-rcar-gen2.c
@@ -32,7 +32,7 @@ static const struct of_device_id cpg_matches[] __initconst = {
ÂÂÂÂÂ { /* sentinel */ }
 -static unsigned int __init get_extal_freq(void)
+static unsigned int __init __maybe_unused get_extal_freq(void)
ÂÂÂÂÂ const struct of_device_id *match;
ÂÂÂÂÂ struct device_node *cpg, *extal;
@@ -60,6 +60,12 @@ static unsigned int __init get_extal_freq(void)
  void __init rcar_gen2_timer_init(void)
+ * If CONFIG_PSCI is enabled then most likely we are running on PSCI-enabled
+ * U-Boot which, we assume, has already taken care of configuring ARCH timer
+ * stuff before switching to non-secure mode.
+ */

I disagree with that statement. CONFIG_ARM_PSCI may be selected in your .config for multiple reasons:
ÂÂÂÂ - CONFIG_XEN will selected it
ÂÂÂÂ - you build a .config targeting multiple platforms

Yet you may still want to boot the kernel on older U-boot. Such change would make it impossible.

If there are code that should not be called when PSCI is used, then you need to make sure the function is not called at runtime.

I got your point.

As I answered in a previous email:

> But "#if !defined(CONFIG_ARM_PSCI)" wraps secure_cntvoff_init() call as
> well, which resets CNTVOFF,

> and this is something I tried to avoid the first from being executed on
> a CPU, which is in SVC mode (when running on top of Xen).

What would be a proper way to avoid calling secure_cntvoff_init() at runtime?

Check that we are already in non-secure mode and/or cntvoff is already 0?



Oleksandr Tyshchenko