diff options
| -rw-r--r-- | arch/parisc/kernel/process.c | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c index 30f92391a93e..cad3e8661cd6 100644 --- a/arch/parisc/kernel/process.c +++ b/arch/parisc/kernel/process.c @@ -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> @@ -184,6 +185,44 @@ int dump_task_fpu (struct task_struct *tsk, elf_fpregset_t *r) } /* + * 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 */ int |