Commit aaa3896b authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

x86/idle: Replace 'x86_idle' function pointer with a static_call 



Typical boot time setup; no need to suffer an indirect call for that.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Tested-by: default avatarTony Lindgren <tony@atomide.com>
Tested-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: default avatarFrederic Weisbecker <frederic@kernel.org>
Reviewed-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20230112195539.453613251@infradead.org
parent 1f7c232e

arch/x86/kernel/process.c

+28 −22
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
#include <linux/cpuidle.h>

#include <linux/acpi.h>

#include <linux/elf-randomize.h>

#include <linux/static_call.h>

#include <trace/events/power.h>

#include <linux/hw_breakpoint.h>

#include <asm/cpu.h>
@@ -694,7 +695,23 @@ void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p) 
unsigned long boot_option_idle_override = IDLE_NO_OVERRIDE;

EXPORT_SYMBOL(boot_option_idle_override);



static void (*x86_idle)(void);

/*

 * We use this if we don't have any better idle routine..

 */

void __cpuidle default_idle(void)

{

	raw_safe_halt();

}

#if defined(CONFIG_APM_MODULE) || defined(CONFIG_HALTPOLL_CPUIDLE_MODULE)

EXPORT_SYMBOL(default_idle);

#endif



DEFINE_STATIC_CALL_NULL(x86_idle, default_idle);



static bool x86_idle_set(void)

{

	return !!static_call_query(x86_idle);

}



#ifndef CONFIG_SMP

static inline void play_dead(void)
@@ -717,28 +734,17 @@ void arch_cpu_idle_dead(void) 
/*

 * Called from the generic idle code.

 */

void arch_cpu_idle(void)

{

	x86_idle();

}



/*

 * We use this if we don't have any better idle routine..

 */

void __cpuidle default_idle(void)

void __cpuidle arch_cpu_idle(void)

{

	raw_safe_halt();

	static_call(x86_idle)();

}

#if defined(CONFIG_APM_MODULE) || defined(CONFIG_HALTPOLL_CPUIDLE_MODULE)

EXPORT_SYMBOL(default_idle);

#endif



#ifdef CONFIG_XEN

bool xen_set_default_idle(void)

{

	bool ret = !!x86_idle;

	bool ret = x86_idle_set();



	x86_idle = default_idle;

	static_call_update(x86_idle, default_idle);



	return ret;

}
@@ -880,20 +886,20 @@ void select_idle_routine(const struct cpuinfo_x86 *c) 
	if (boot_option_idle_override == IDLE_POLL && smp_num_siblings > 1)

		pr_warn_once("WARNING: polling idle and HT enabled, performance may degrade\n");

#endif

	if (x86_idle || boot_option_idle_override == IDLE_POLL)

	if (x86_idle_set() || boot_option_idle_override == IDLE_POLL)

		return;



	if (boot_cpu_has_bug(X86_BUG_AMD_E400)) {

		pr_info("using AMD E400 aware idle routine\n");

		x86_idle = amd_e400_idle;

		static_call_update(x86_idle, amd_e400_idle);

	} else if (prefer_mwait_c1_over_halt(c)) {

		pr_info("using mwait in idle threads\n");

		x86_idle = mwait_idle;

		static_call_update(x86_idle, mwait_idle);

	} else if (cpu_feature_enabled(X86_FEATURE_TDX_GUEST)) {

		pr_info("using TDX aware idle routine\n");

		x86_idle = tdx_safe_halt;

		static_call_update(x86_idle, tdx_safe_halt);

	} else

		x86_idle = default_idle;

		static_call_update(x86_idle, default_idle);

}



void amd_e400_c1e_apic_setup(void)
@@ -946,7 +952,7 @@ static int __init idle_setup(char *str) 
		 * To continue to load the CPU idle driver, don't touch

		 * the boot_option_idle_override.

		 */

		x86_idle = default_idle;

		static_call_update(x86_idle, default_idle);

		boot_option_idle_override = IDLE_HALT;

	} else if (!strcmp(str, "nomwait")) {

		/*