kernel_optimize_test/arch/arm/kernel
Benjamin Gaignard 022eb8ae8b ARM: 8938/1: kernel: initialize broadcast hrtimer based clock event device
On platforms implementing CPU power management, the CPUidle subsystem
can allow CPUs to enter idle states where local timers logic is lost on power
down. To keep the software timers functional the kernel relies on an
always-on broadcast timer to be present in the platform to relay the
interrupt signalling the timer expiries.

For platforms implementing CPU core gating that do not implement an always-on
HW timer or implement it in a broken way, this patch adds code to initialize
the kernel hrtimer based clock event device upon boot (which can be chosen as
tick broadcast device by the kernel).
It relies on a dynamically chosen CPU to be always powered-up. This CPU then
relays the timer interrupt to CPUs in deep-idle states through its HW local
timer device.

Having a CPU always-on has implications on power management platform
capabilities and makes CPUidle suboptimal, since at least a CPU is kept
always in a shallow idle state by the kernel to relay timer interrupts,
but at least leaves the kernel with a functional system with some working
power management capabilities.

The hrtimer based clock event device is unconditionally registered, but
has the lowest possible rating such that any broadcast-capable HW clock
event device present will be chosen in preference as the tick broadcast
device.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2019-11-16 10:51:24 +00:00
..
.gitignore
arch_timer.c ARM: 8913/1: arch_timer: include <asm/arch_timer.h> 2019-10-27 21:14:43 +00:00
armksyms.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
asm-offsets.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
atags_compat.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
atags_parse.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
atags_proc.c
atags.h ARM: mark setup_machine_tags() stub as __init __noreturn 2019-05-14 19:52:48 -07:00
bios32.c
bugs.c treewide: fix typos of SPDX-License-Identifier 2019-06-01 18:29:58 +02:00
cpuidle.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 159 2019-05-30 11:26:37 -07:00
crash_dump.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
debug.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
devtree.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
dma-isa.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
dma.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
early_printk.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
efi.c mm/pgtable: drop pgtable_t variable from pte_fn_t functions 2019-07-12 11:05:46 -07:00
elf.c
entry-armv.S docs: arm: convert docs to ReST and rename to *.rst 2019-07-15 09:20:24 -03:00
entry-common.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
entry-ftrace.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
entry-header.S
entry-v7m.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
fiq.c
fiqasm.S
ftrace.c
head-common.S ARM: 8914/1: NOMMU: Fix exc_ret for XIP 2019-10-10 22:23:20 +01:00
head-inflate-data.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
head-nommu.S ARM: 8914/1: NOMMU: Fix exc_ret for XIP 2019-10-10 22:23:20 +01:00
head.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
hibernate.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 194 2019-05-30 11:29:22 -07:00
hw_breakpoint.c ARM: 8927/1: ARM/hw_breakpoint: add more ARMv8 debug architecture versions support 2019-11-15 22:21:08 +00:00
hyp-stub.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 1 2019-05-21 11:28:39 +02:00
insn.c
io.c
irq.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
isa.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
iwmmxt.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
jump_label.c
kgdb.c
machine_kexec.c
Makefile ARM: 8918/2: only build return_address() if needed 2019-11-15 22:21:07 +00:00
module-plts.c ARM: 8910/1: fix missing declartion of module_frob_arch_sections 2019-10-27 21:14:38 +00:00
module.c Modules updates for v5.3 2019-07-18 12:06:57 -07:00
module.lds
opcodes.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
paravirt.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
patch.c
perf_callchain.c
perf_event_v6.c
perf_event_v7.c ARM: 8873/1: perf: cleanup cppcheck shifting warning 2019-08-23 11:38:46 +01:00
perf_event_xscale.c
perf_regs.c
pj4-cp0.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
process.c ARM: 8920/1: share get_signal_page from signal.c to process.c 2019-10-31 16:58:53 +00:00
psci_smp.c ARM: 8919/1: make unexported functions static 2019-10-31 16:58:52 +00:00
ptrace.c Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2019-07-08 21:48:15 -07:00
reboot.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
reboot.h
relocate_kernel.S
return_address.c ARM: 8918/2: only build return_address() if needed 2019-11-15 22:21:07 +00:00
setup.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
signal.c ARM: signal: Mark expected switch fall-through 2019-08-09 19:47:15 -05:00
signal.h ARM: 8920/1: share get_signal_page from signal.c to process.c 2019-10-31 16:58:53 +00:00
sigreturn_codes.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
sleep.S
smccc-call.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 282 2019-06-05 17:36:37 +02:00
smp_scu.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
smp_tlb.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
smp_twd.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
smp.c ARM: 8872/1: Use common outgoing-CPU-notification code 2019-08-23 11:38:45 +01:00
stacktrace.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
suspend.c
swp_emulate.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
sys_arm.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
sys_oabi-compat.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
tcm.c ARM: 8925/1: tcm: include <asm/tcm.h> for missing declarations 2019-10-31 16:58:56 +00:00
thumbee.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
time.c ARM: 8938/1: kernel: initialize broadcast hrtimer based clock event device 2019-11-16 10:51:24 +00:00
topology.c ARM: 8922/1: parse_dt_topology() rate is pointer to __be32 2019-10-31 16:58:54 +00:00
traps.c Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2019-07-08 21:48:15 -07:00
unwind.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
v7m.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
vdso.c ARM: 8930/1: Add support for generic vDSO 2019-11-15 22:21:12 +00:00
vmlinux-xip.lds.S
vmlinux.lds.h
vmlinux.lds.S
xscale-cp0.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00