Commit 92dcd3d3 authored by Johannes Berg's avatar Johannes Berg Committed by Richard Weinberger
Browse files

um: Allow PM with suspend-to-idle 



In order to be able to experiment with suspend in UML, add the
minimal work to be able to suspend (s2idle) an instance of UML,
and be able to wake it back up from that state with the USR1
signal sent to the main UML process.

Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
Acked-By: default avatarAnton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: default avatarRichard Weinberger <richard@nod.at>
parent 2701c1bd

arch/um/Kconfig

+5 −0
Original line number Diff line number Diff line
@@ -192,3 +192,8 @@ config UML_TIME_TRAVEL_SUPPORT 
endmenu



source "arch/um/drivers/Kconfig"



config ARCH_SUSPEND_POSSIBLE

	def_bool y



source "kernel/power/Kconfig"

arch/um/include/shared/kern_util.h

+2 −0
Original line number Diff line number Diff line
@@ -39,6 +39,8 @@ extern int is_syscall(unsigned long addr); 


extern void timer_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs);



extern void uml_pm_wake(void);



extern int start_uml(void);

extern void paging_init(void);

arch/um/include/shared/os.h

+1 −0
Original line number Diff line number Diff line
@@ -241,6 +241,7 @@ extern int set_signals(int enable); 
extern int set_signals_trace(int enable);

extern int os_is_signal_stack(void);

extern void deliver_alarm(void);

extern void register_pm_wake_signal(void);



/* util.c */

extern void stack_protections(unsigned long address);

arch/um/kernel/um_arch.c

+25 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include <linux/sched.h>

#include <linux/sched/task.h>

#include <linux/kmsg_dump.h>

#include <linux/suspend.h>



#include <asm/processor.h>

#include <asm/sections.h>
@@ -377,3 +378,27 @@ void *text_poke(void *addr, const void *opcode, size_t len) 
void text_poke_sync(void)

{

}



#ifdef CONFIG_PM_SLEEP

void uml_pm_wake(void)

{

	pm_system_wakeup();

}



static int init_pm_wake_signal(void)

{

	/*

	 * In external time-travel mode we can't use signals to wake up

	 * since that would mess with the scheduling. We'll have to do

	 * some additional work to support wakeup on virtio devices or

	 * similar, perhaps implementing a fake RTC controller that can

	 * trigger wakeup (and request the appropriate scheduling from

	 * the external scheduler when going to suspend.)

	 */

	if (time_travel_mode != TT_MODE_EXTERNAL)

		register_pm_wake_signal();

	return 0;

}



late_initcall(init_pm_wake_signal);

#endif

arch/um/os-Linux/signal.c

+13 −1
Original line number Diff line number Diff line
@@ -136,6 +136,16 @@ void set_sigstack(void *sig_stack, int size) 
		panic("enabling signal stack failed, errno = %d\n", errno);

}



static void sigusr1_handler(int sig, struct siginfo *unused_si, mcontext_t *mc)

{

	uml_pm_wake();

}



void register_pm_wake_signal(void)

{

	set_handler(SIGUSR1);

}



static void (*handlers[_NSIG])(int sig, struct siginfo *si, mcontext_t *mc) = {

	[SIGSEGV] = sig_handler,

	[SIGBUS] = sig_handler,
@@ -145,7 +155,9 @@ static void (*handlers[_NSIG])(int sig, struct siginfo *si, mcontext_t *mc) = { 


	[SIGIO] = sig_handler,

	[SIGWINCH] = sig_handler,

	[SIGALRM] = timer_alarm_handler

	[SIGALRM] = timer_alarm_handler,



	[SIGUSR1] = sigusr1_handler,

};



static void hard_handler(int sig, siginfo_t *si, void *p)

CRA Git | Maintained and supported by SUSTech CRA and CCSE