This minor patch enables config option GENERIC_IDLE_POLL_SETUP for arch powerpc. This should add support for kernel param 'nohlt'.
Powerpc kernel also supports another kernel boot-time param called 'powersave' which can also be used to disable all cpu idle-states and forces CPU to an idle-loop similar to what cpu_idle_poll() does. Hence this patch also updates the handling of 'powersave=off' kernel param to enable generic cpu idle-loop if its enabled. Signed-off-by: Vaibhav Jain<vaib...@linux.ibm.com> --- Changelog: Since v1: https://lore.kernel.org/all/20230818050739.827851-1-vaib...@linux.ibm.com * Updated powersave_off() to enable generic cpu idle-loop if 'powersave=off' kernel arg is given. [Mpe] * Update patch description --- Documentation/admin-guide/kernel-parameters.txt | 2 +- arch/powerpc/Kconfig | 1 + arch/powerpc/kernel/idle.c | 3 +++ 3 files changed, 5 insertions(+), 1 deletion(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 722b6eca2e93..6b657ebafcfb 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3738,7 +3738,7 @@ nohibernate [HIBERNATION] Disable hibernation and resume. - nohlt [ARM,ARM64,MICROBLAZE,MIPS,SH] Forces the kernel to + nohlt [ARM,ARM64,MICROBLAZE,MIPS,PPC,SH] Forces the kernel to busy wait in do_idle() and not use the arch_cpu_idle() implementation; requires CONFIG_GENERIC_IDLE_POLL_SETUP to be effective. This is useful on platforms where the diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 0b1172cbeccb..574661403800 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -193,6 +193,7 @@ config PPC select GENERIC_CPU_VULNERABILITIES if PPC_BARRIER_NOSPEC select GENERIC_EARLY_IOREMAP select GENERIC_GETTIMEOFDAY + select GENERIC_IDLE_POLL_SETUP select GENERIC_IRQ_SHOW select GENERIC_IRQ_SHOW_LEVEL select GENERIC_PCI_IOMAP if PCI diff --git a/arch/powerpc/kernel/idle.c b/arch/powerpc/kernel/idle.c index b1c0418b25c8..7367a0698459 100644 --- a/arch/powerpc/kernel/idle.c +++ b/arch/powerpc/kernel/idle.c @@ -21,6 +21,7 @@ #include <linux/cpu.h> #include <linux/sysctl.h> #include <linux/tick.h> +#include <linux/cpu.h> #include <asm/processor.h> #include <asm/cputable.h> @@ -35,6 +36,8 @@ EXPORT_SYMBOL(cpuidle_disable); static int __init powersave_off(char *arg) { + /* Use generic idle loop if thats available */ + cpu_idle_poll_ctrl(true); ppc_md.power_save = NULL; cpuidle_disable = IDLE_POWERSAVE_OFF; return 1; -- 2.41.0
