parisc: qemu idle sleep support (310d8278) · Commits · 戴 / test

arch/parisc/kernel/process.c

+39 −0

Original line number	Diff line number	Diff line
		@@ -39,6 +39,7 @@
		#include <linux/kernel.h>
		#include <linux/mm.h>
		#include <linux/fs.h>
		#include <linux/cpu.h>
		#include <linux/module.h>
		#include <linux/personality.h>
		#include <linux/ptrace.h>
		@@ -183,6 +184,44 @@ int dump_task_fpu (struct task_struct tsk, elf_fpregset_t r)
		return 1;
		}

		/*
		* Idle thread support
		*
		* Detect when running on QEMU with SeaBIOS PDC Firmware and let
		* QEMU idle the host too.
		*/

		int running_on_qemu __read_mostly;

		void __cpuidle arch_cpu_idle_dead(void)
		{
		/* nop on real hardware, qemu will offline CPU. */
		asm volatile("or %%r31,%%r31,%%r31\n":::);
		}

		void __cpuidle arch_cpu_idle(void)
		{
		local_irq_enable();

		/* nop on real hardware, qemu will idle sleep. */
		asm volatile("or %%r10,%%r10,%%r10\n":::);
		}

		static int __init parisc_idle_init(void)
		{
		const char *marker;

		/* check QEMU/SeaBIOS marker in PAGE0 */
		marker = (char *) &PAGE0->pad0;
		running_on_qemu = (memcmp(marker, "SeaBIOS", 8) == 0);

		if (!running_on_qemu)
		cpu_idle_poll_ctrl(1);

		return 0;
		}
		arch_initcall(parisc_idle_init);

		/*
		* Copy architecture-specific thread state
		*/