linux-stable.git/arch/mips/kernel/idle.c, branch linux-rolling-stable

MIPS: Fix idle VS timer enqueue

2025-04-27T08:12:03+00:00

MIPS re-enables interrupts on its idle routine and performs
a TIF_NEED_RESCHED check afterwards before putting the CPU to sleep.

The IRQs firing between the check and the 'wait' instruction may set the
TIF_NEED_RESCHED flag. In order to deal with this possible race, IRQs
interrupting __r4k_wait() rollback their return address to the
beginning of __r4k_wait() so that TIF_NEED_RESCHED is checked
again before going back to sleep.

However idle IRQs can also queue timers that may require a tick
reprogramming through a new generic idle loop iteration but those timers
would go unnoticed here because __r4k_wait() only checks
TIF_NEED_RESCHED. It doesn't check for pending timers.

Fix this with fast-forwarding idle IRQs return address to the end of the
idle routine instead of the beginning, so that the generic idle loop
handles both TIF_NEED_RESCHED and pending timers.

CONFIG_CPU_MICROMIPS has been removed along with the nop instructions.
There, NOPs are 2 byte in size, so change the code with 3 _ssnop which are
always 4 byte and remove the ifdef. Added ehb to make sure the hazard
is always cleared.

Fixes: c65a5480ff29 ("[MIPS] Fix potential latency problem due to non-atomic cpu_wait.")
Signed-off-by: Marco Crivellari 
Signed-off-by: Maciej W. Rozycki 
Acked-by: Frederic Weisbecker 
Signed-off-by: Thomas Bogendoerfer

cpuidle,arch: Mark all regular cpuidle_state:: Enter methods __cpuidle

2023-01-13T10:48:18+00:00

For all cpuidle drivers that do not use CPUIDLE_FLAG_RCU_IDLE (iow,
the simple ones) make sure all the functions are marked __cpuidle.

( due to lack of noinstr validation on these platforms it is entirely
  possible this isn't complete )

Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Ingo Molnar 
Link: https://lore.kernel.org/r/20230112195542.335211484@infradead.org

arch/idle: Change arch_cpu_idle() behavior: always exit with IRQs disabled

2023-01-13T10:48:15+00:00

Current arch_cpu_idle() is called with IRQs disabled, but will return
with IRQs enabled.

However, the very first thing the generic code does after calling
arch_cpu_idle() is raw_local_irq_disable(). This means that
architectures that can idle with IRQs disabled end up doing a
pointless 'enable-disable' dance.

Therefore, push this IRQ disabling into the idle function, meaning
that those architectures can avoid the pointless IRQ state flipping.

Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Ingo Molnar 
Tested-by: Tony Lindgren 
Tested-by: Ulf Hansson 
Reviewed-by: Gautham R. Shenoy 
Acked-by: Mark Rutland  [arm64]
Acked-by: Rafael J. Wysocki 
Acked-by: Guo Ren 
Acked-by: Frederic Weisbecker 
Link: https://lore.kernel.org/r/20230112195540.618076436@infradead.org

MIPS: fix typos in comments

2022-05-04T20:22:59+00:00

Various spelling mistakes in comments.
Detected with the help of Coccinelle.

Signed-off-by: Julia Lawall 
Signed-off-by: Thomas Bogendoerfer

MIPS: Remove TX39XX support

2022-03-01T09:07:22+00:00

No (active) developer owns this hardware, so let's remove Linux support.

Signed-off-by: Thomas Bogendoerfer 
Acked-by: Guenter Roeck 
Reviewed-by: Geert Uytterhoeven 
Tested-by: Geert Uytterhoeven 
Acked-by: Atsushi Nemoto

MIPS: Remove NETLOGIC support

2021-10-24T15:24:47+00:00

No (active) developer owns this hardware, so let's remove Linux support.

Signed-off-by: Thomas Bogendoerfer

Revert "MIPS: Remove unused R4300 CPU support"

2021-01-22T10:39:45+00:00

This reverts commit f9065b54d437c4660e3d974ad9ce5188c068cd76.

We're adding Nintendo 64 support, so the VR4300 is no longer unused.

Signed-off-by: Lauri Kasanen 
Signed-off-by: Thomas Bogendoerfer

sched/idle: Fix arch_cpu_idle() vs tracing

2020-11-24T15:47:35+00:00

We call arch_cpu_idle() with RCU disabled, but then use
local_irq_{en,dis}able(), which invokes tracing, which relies on RCU.

Switch all arch_cpu_idle() implementations to use
raw_local_irq_{en,dis}able() and carefully manage the
lockdep,rcu,tracing state like we do in entry.

(XXX: we really should change arch_cpu_idle() to not return with
interrupts enabled)

Reported-by: Sven Schnelle 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Mark Rutland 
Tested-by: Mark Rutland 
Link: https://lkml.kernel.org/r/20201120114925.594122626@infradead.org

MIPS: Use fallthrough for arch/mips

2020-05-07T09:55:47+00:00

Convert the various /* fallthrough */ comments to the pseudo-keyword
fallthrough;

Done via script:
https://lore.kernel.org/lkml/b56602fcf79f849e733e7b521bb0e17895d390fa.1582230379.git.joe@perches.com/

Signed-off-by: Liangliang Huang 
Reviewed-by: Huacai Chen 
Signed-off-by: Thomas Bogendoerfer

MIPS: Kernel: Identify Loongson-2K processors

2020-04-26T16:29:01+00:00

Loongson-2K (Loongson64 Reduced) is a family of SoC shipped with
gs264e core.

Signed-off-by: Jiaxun Yang 
Signed-off-by: Thomas Bogendoerfer