diff --git a/arch/um/Kconfig b/arch/um/Kconfig
index 64fe8d5c067acbf369272fb01d827afd1bb3fe0d..740d8a922e4867e457c30c513fb3fa37e912fc8c 100644
--- a/arch/um/Kconfig
+++ b/arch/um/Kconfig
@@ -250,18 +250,6 @@ config KERNEL_STACK_ORDER
be 1 << order pages. The default is OK unless you're running Valgrind
on UML, in which case, set this to 3.
-config UML_REAL_TIME_CLOCK
- bool "Real-time Clock"
- default y
- help
- This option makes UML time deltas match wall clock deltas. This
- should normally be enabled. The exception would be if you are
- debugging with UML and spend long times with UML stopped at a
- breakpoint. In this case, when UML is restarted, it will call the
- timer enough times to make up for the time spent at the breakpoint.
- This could result in a noticeable lag. If this is a problem, then
- disable this option.
-
endmenu
source "init/Kconfig"
diff --git a/arch/um/defconfig b/arch/um/defconfig
index 9f105c87fcc40b5cecf5859c96e8c70c4fe04bef..1cbbe980f10621bfcf0d0f1d595463aa2367c354 100644
--- a/arch/um/defconfig
+++ b/arch/um/defconfig
@@ -73,8 +73,8 @@ CONFIG_FLATMEM=y
CONFIG_FLAT_NODE_MEM_MAP=y
# CONFIG_SPARSEMEM_STATIC is not set
CONFIG_SPLIT_PTLOCK_CPUS=4
-# CONFIG_TICK_ONESHOT is not set
-# CONFIG_NO_HZ is not set
+CONFIG_TICK_ONESHOT=y
+CONFIG_NO_HZ=y
CONFIG_HIGH_RES_TIMERS=y
CONFIG_LD_SCRIPT_DYN=y
CONFIG_NET=y
@@ -87,7 +87,6 @@ CONFIG_MAGIC_SYSRQ=y
CONFIG_NEST_LEVEL=0
# CONFIG_HIGHMEM is not set
CONFIG_KERNEL_STACK_ORDER=0
-CONFIG_UML_REAL_TIME_CLOCK=y
#
# Code maturity level options
diff --git a/arch/um/include/os.h b/arch/um/include/os.h
index a6d80721d3c404944af2f5bc06483b5b9a2bbf4d..e4f2fe11ba5076d482c002edc4d7ae9cf35bdb77 100644
--- a/arch/um/include/os.h
+++ b/arch/um/include/os.h
@@ -254,6 +254,7 @@ extern void os_dump_core(void);
extern int switch_timers(int to_real);
extern void idle_sleep(int secs);
extern int set_interval(void);
+extern int timer_one_shot(int ticks);
extern void disable_timer(void);
extern void uml_idle_timer(void);
extern unsigned long long os_nsecs(void);
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index 56d75afedbf7de3bd2d26c6f81b9500a4a099593..aef494b6b81ad2488c01a89ebae9c393b06a3353 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -13,6 +13,7 @@
#include "linux/ptrace.h"
#include "linux/random.h"
#include "linux/sched.h"
+#include "linux/tick.h"
#include "linux/threads.h"
#include "asm/pgtable.h"
#include "asm/uaccess.h"
@@ -244,9 +245,11 @@ void default_idle(void)
if (need_resched())
schedule();
+ tick_nohz_stop_sched_tick();
switch_timers(1);
idle_sleep(10);
switch_timers(0);
+ tick_nohz_restart_sched_tick();
}
}
diff --git a/arch/um/kernel/time.c b/arch/um/kernel/time.c
index 3cb7135e5c47ad934ca4b50748f6ec4ea319012d..2acdc7efb2ac7a94e7cf9a361b6b2fbee0a38538 100644
--- a/arch/um/kernel/time.c
+++ b/arch/um/kernel/time.c
@@ -20,41 +20,12 @@ unsigned long long sched_clock(void)
return (unsigned long long)jiffies_64 * (1000000000 / HZ);
}
-#ifdef CONFIG_UML_REAL_TIME_CLOCK
-static unsigned long long prev_nsecs[NR_CPUS];
-static long long delta[NR_CPUS]; /* Deviation per interval */
-#endif
-
void timer_handler(int sig, struct uml_pt_regs *regs)
{
- unsigned long long ticks = 0;
unsigned long flags;
-#ifdef CONFIG_UML_REAL_TIME_CLOCK
- int c = cpu();
- if (prev_nsecs[c]) {
- /* We've had 1 tick */
- unsigned long long nsecs = os_nsecs();
-
- delta[c] += nsecs - prev_nsecs[c];
- prev_nsecs[c] = nsecs;
-
- /* Protect against the host clock being set backwards */
- if (delta[c] < 0)
- delta[c] = 0;
-
- ticks += (delta[c] * HZ) / BILLION;
- delta[c] -= (ticks * BILLION) / HZ;
- }
- else prev_nsecs[c] = os_nsecs();
-#else
- ticks = 1;
-#endif
local_irq_save(flags);
- while (ticks > 0) {
- do_IRQ(TIMER_IRQ, regs);
- ticks--;
- }
+ do_IRQ(TIMER_IRQ, regs);
local_irq_restore(flags);
}
@@ -68,10 +39,8 @@ static void itimer_set_mode(enum clock_event_mode mode,
case CLOCK_EVT_MODE_SHUTDOWN:
case CLOCK_EVT_MODE_UNUSED:
- disable_timer();
- break;
case CLOCK_EVT_MODE_ONESHOT:
- BUG();
+ disable_timer();
break;
case CLOCK_EVT_MODE_RESUME:
@@ -79,13 +48,19 @@ static void itimer_set_mode(enum clock_event_mode mode,
}
}
+static int itimer_next_event(unsigned long delta,
+ struct clock_event_device *evt)
+{
+ return timer_one_shot(delta + 1);
+}
+
static struct clock_event_device itimer_clockevent = {
.name = "itimer",
.rating = 250,
.cpumask = CPU_MASK_ALL,
- .features = CLOCK_EVT_FEAT_PERIODIC,
+ .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
.set_mode = itimer_set_mode,
- .set_next_event = NULL,
+ .set_next_event = itimer_next_event,
.shift = 32,
.irq = 0,
};
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index 0036164bb0fb48e1b99d0f2827865ff8f33c97fc..3e64814e888ef5d7670aff91483f21e2e3e395b4 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -287,10 +287,18 @@ int start_userspace(unsigned long stub_stack)
void userspace(struct uml_pt_regs *regs)
{
+ struct itimerval timer;
+ unsigned long long nsecs, now;
int err, status, op, pid = userspace_pid[0];
/* To prevent races if using_sysemu changes under us.*/
int local_using_sysemu;
+ if (getitimer(ITIMER_VIRTUAL, &timer))
+ printk("Failed to get itimer, errno = %d\n", errno);
+ nsecs = timer.it_value.tv_sec * BILLION +
+ timer.it_value.tv_usec * 1000;
+ nsecs += os_nsecs();
+
while (1) {
restore_registers(pid, regs);
@@ -333,8 +341,18 @@ void userspace(struct uml_pt_regs *regs)
case SIGTRAP:
relay_signal(SIGTRAP, regs);
break;
- case SIGIO:
case SIGVTALRM:
+ now = os_nsecs();
+ if(now < nsecs)
+ break;
+ block_signals();
+ (*sig_info[sig])(sig, regs);
+ unblock_signals();
+ nsecs = timer.it_value.tv_sec * BILLION +
+ timer.it_value.tv_usec * 1000;
+ nsecs += os_nsecs();
+ break;
+ case SIGIO:
case SIGILL:
case SIGBUS:
case SIGFPE:
@@ -378,6 +396,7 @@ __initcall(init_thread_regs);
int copy_context_skas0(unsigned long new_stack, int pid)
{
+ struct timeval tv = { .tv_sec = 0, .tv_usec = 1000000 / UM_HZ };
int err;
unsigned long current_stack = current_stub_stack();
struct stub_data *data = (struct stub_data *) current_stack;
@@ -392,9 +411,9 @@ int copy_context_skas0(unsigned long new_stack, int pid)
*data = ((struct stub_data) { .offset = MMAP_OFFSET(new_offset),
.fd = new_fd,
.timer = ((struct itimerval)
- { { 0, 1000000 / UM_HZ },
- { 0, 1000000 / UM_HZ }})
- });
+ { .it_value = tv,
+ .it_interval = tv }) });
+
err = ptrace_setregs(pid, thread_regs);
if (err < 0)
panic("copy_context_skas0 : PTRACE_SETREGS failed, "
diff --git a/arch/um/os-Linux/time.c b/arch/um/os-Linux/time.c
index 6ff3d98281ba77458be132425a20229f731b521b..9ffc61ac8ed634a0996f7fa08b72a0ab19b0526d 100644
--- a/arch/um/os-Linux/time.c
+++ b/arch/um/os-Linux/time.c
@@ -26,6 +26,21 @@ int set_interval(void)
return 0;
}
+int timer_one_shot(int ticks)
+{
+ unsigned long usec = ticks * 1000000 / UM_HZ;
+ unsigned long sec = usec / 1000000;
+ struct itimerval interval;
+
+ usec %= 1000000;
+ interval = ((struct itimerval) { { 0, 0 }, { sec, usec } });
+
+ if (setitimer(ITIMER_VIRTUAL, &interval, NULL) == -1)
+ return -errno;
+
+ return 0;
+}
+
void disable_timer(void)
{
struct itimerval disable = ((struct itimerval) { { 0, 0 }, { 0, 0 }});
@@ -74,7 +89,7 @@ unsigned long long os_nsecs(void)
struct timeval tv;
gettimeofday(&tv, NULL);
- return (unsigned long long) tv.tv_sec * BILLION + tv.tv_usec * 1000;
+ return timeval_to_ns(&tv);
}
void idle_sleep(int secs)