Commit 6b10fef0 authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

loongarch: Provide noinstr sched_clock_read() 



With the intent to provide local_clock_noinstr(), a variant of
local_clock() that's safe to be called from noinstr code (with the
assumption that any such code will already be non-preemptible),
prepare for things by providing a noinstr sched_clock_read() function.

Specifically, preempt_enable_*() calls out to schedule(), which upsets
noinstr validation efforts.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>  # Hyper-V
Link: https://lore.kernel.org/r/20230519102715.502547082@infradead.org
parent 24ee7607

arch/loongarch/include/asm/loongarch.h

+1 −1
Original line number Diff line number Diff line
@@ -1167,7 +1167,7 @@ static __always_inline void iocsr_write64(u64 val, u32 reg) 


#ifndef __ASSEMBLY__



static inline u64 drdtime(void)

static __always_inline u64 drdtime(void)

{

	int rID = 0;

	u64 val = 0;

arch/loongarch/kernel/time.c

+3 −3
Original line number Diff line number Diff line
@@ -190,9 +190,9 @@ static u64 read_const_counter(struct clocksource *clk) 
	return drdtime();

}



static u64 native_sched_clock(void)

static noinstr u64 sched_clock_read(void)

{

	return read_const_counter(NULL);

	return drdtime();

}



static struct clocksource clocksource_const = {
@@ -211,7 +211,7 @@ int __init constant_clocksource_init(void) 


	res = clocksource_register_hz(&clocksource_const, freq);



	sched_clock_register(native_sched_clock, 64, freq);

	sched_clock_register(sched_clock_read, 64, freq);



	pr_info("Constant clock source device register\n");