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authorNicolas Pitre <nicolas.pitre@linaro.org>2013-09-25 23:26:24 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2013-10-03 10:36:37 +0100
commitd0cdef6e87ebc1241d7e407d5e1b14e6bb836ae9 (patch)
tree61aa1f92ae839e1afb3e37b0f68375506bf55088
parent40190c85f427dcfdbab5dbef4ffd2510d649da1f (diff)
downloadlinux-d0cdef6e87ebc1241d7e407d5e1b14e6bb836ae9.tar.bz2
ARM: 7842/1: MCPM: don't explode if invoked without being initialized first
Currently mcpm_cpu_power_down() and mcpm_cpu_suspend() trigger BUG() if mcpm_platform_register() is not called beforehand. This may occur for many reasons such as some incomplete device tree passed to the kernel or the like. Let's be nicer to users and avoid killing the kernel if that happens by logging a warning and returning to the caller. The mcpm_cpu_suspend() user is already set to deal with this situation, and so is cpu_die() invoking mcpm_cpu_die(). The problematic case would have been the B.L switcher's usage of mcpm_cpu_power_down(), however it has to call mcpm_cpu_power_up() first which is already set to catch an error resulting from a missing mcpm_platform_register() call. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
-rw-r--r--arch/arm/common/mcpm_entry.c6
-rw-r--r--arch/arm/include/asm/mcpm.h14
2 files changed, 14 insertions, 6 deletions
diff --git a/arch/arm/common/mcpm_entry.c b/arch/arm/common/mcpm_entry.c
index 370236dd1a03..990250965f2c 100644
--- a/arch/arm/common/mcpm_entry.c
+++ b/arch/arm/common/mcpm_entry.c
@@ -51,7 +51,8 @@ void mcpm_cpu_power_down(void)
{
phys_reset_t phys_reset;
- BUG_ON(!platform_ops);
+ if (WARN_ON_ONCE(!platform_ops || !platform_ops->power_down))
+ return;
BUG_ON(!irqs_disabled());
/*
@@ -93,7 +94,8 @@ void mcpm_cpu_suspend(u64 expected_residency)
{
phys_reset_t phys_reset;
- BUG_ON(!platform_ops);
+ if (WARN_ON_ONCE(!platform_ops || !platform_ops->suspend))
+ return;
BUG_ON(!irqs_disabled());
/* Very similar to mcpm_cpu_power_down() */
diff --git a/arch/arm/include/asm/mcpm.h b/arch/arm/include/asm/mcpm.h
index 0f7b7620e9a5..fc82a88f5b69 100644
--- a/arch/arm/include/asm/mcpm.h
+++ b/arch/arm/include/asm/mcpm.h
@@ -76,8 +76,11 @@ int mcpm_cpu_power_up(unsigned int cpu, unsigned int cluster);
*
* This must be called with interrupts disabled.
*
- * This does not return. Re-entry in the kernel is expected via
- * mcpm_entry_point.
+ * On success this does not return. Re-entry in the kernel is expected
+ * via mcpm_entry_point.
+ *
+ * This will return if mcpm_platform_register() has not been called
+ * previously in which case the caller should take appropriate action.
*/
void mcpm_cpu_power_down(void);
@@ -98,8 +101,11 @@ void mcpm_cpu_power_down(void);
*
* This must be called with interrupts disabled.
*
- * This does not return. Re-entry in the kernel is expected via
- * mcpm_entry_point.
+ * On success this does not return. Re-entry in the kernel is expected
+ * via mcpm_entry_point.
+ *
+ * This will return if mcpm_platform_register() has not been called
+ * previously in which case the caller should take appropriate action.
*/
void mcpm_cpu_suspend(u64 expected_residency);