powerpc/idle: Add support for nohlt

This patch enables config option GENERIC_IDLE_POLL_SETUP for arch
powerpc. This adds 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. This
patch however makes powerpc kernel-parameters better aligned to the
generic boot-time parameters.

Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230818050739.827851-1-vaibhav@linux.ibm.com

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index cac4643..fd9f21b 100644 (file)
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3717,7 +3717,7 @@
 
        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 b7a4cb5..cb0a899 100644 (file)
--- 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