In order to cooperate with UML's irq infrastructure and nommu threads
based on host threads, irq handlers shall synchronize the our
scheduler which is controlled by struct lkl_cpu. To do that, the irq
infra notifies its entry of handlers by obtaining cpu access of thread
scheduler (lkl_cpu_try_run_irq) and its release (lkl_cpu_put).
In additon to that, in order to stick the signal handler's thread to the
one of the idle thread, several required configurations of (thread's)
signal mask are added: otherwise handlers running on arbitrary thread
cannot obtain cpu access and immediately fall into pending interrupt
which may slow down the delivery of signals.
Signed-off-by: Hajime Tazaki <thehajime@xxxxxxxxx>
---
arch/um/include/shared/os.h | 1 +
arch/um/kernel/irq.c | 13 +++++++++++++
arch/um/kernel/time.c | 2 ++
arch/um/nommu/include/asm/cpu.h | 3 +++
arch/um/nommu/um/cpu.c | 17 ++++++++++++++---
arch/um/nommu/um/setup.c | 5 +++++
arch/um/nommu/um/threads.c | 3 +++
tools/um/uml/signal.c | 12 ++++++++++--
8 files changed, 51 insertions(+), 5 deletions(-)
diff --git a/arch/um/include/shared/os.h b/arch/um/include/shared/os.h
index f467d28fc0b4..0da3ce22e16f 100644
--- a/arch/um/include/shared/os.h
+++ b/arch/um/include/shared/os.h
@@ -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 set_pending_signals(int sig);
/* util.c */
extern void stack_protections(unsigned long address);
diff --git a/arch/um/kernel/irq.c b/arch/um/kernel/irq.c
index 3577118bb4a5..4ce7f5fef7f8 100644
--- a/arch/um/kernel/irq.c
+++ b/arch/um/kernel/irq.c
@@ -19,6 +19,7 @@
#include <kern_util.h>
#include <os.h>
#include <irq_user.h>
+#include <asm/cpu.h>
extern void free_irqs(void);
@@ -541,6 +542,11 @@ unsigned long to_irq_stack(unsigned long *mask_out)
unsigned long mask, old;
int nested;
+#ifndef CONFIG_MMU
+ if (!nommu_irq_enter(ffs(*mask_out) - 1))
+ return 1;
+#endif
+
mask = xchg(&pending_mask, *mask_out);
if (mask != 0) {
/*
@@ -557,6 +563,10 @@ unsigned long to_irq_stack(unsigned long *mask_out)
old |= mask;
mask = xchg(&pending_mask, old);
} while (mask != old);
+
+#ifndef CONFIG_MMU
+ nommu_irq_exit();
+#endif
return 1;
}
@@ -594,6 +604,9 @@ unsigned long from_irq_stack(int nested)
*to = *ti;
mask = xchg(&pending_mask, 0);
+#ifndef CONFIG_MMU
+ nommu_irq_exit();
+#endif
return mask & ~1;
}
diff --git a/arch/um/kernel/time.c b/arch/um/kernel/time.c
index 25eaa6a0c658..9e141fe8fe27 100644
--- a/arch/um/kernel/time.c
+++ b/arch/um/kernel/time.c
@@ -597,11 +597,13 @@ static struct clock_event_device timer_clockevent = {
static irqreturn_t um_timer(int irq, void *dev)
{
+#ifdef CONFIG_MMU
if (get_current()->mm != NULL)
{
/* userspace - relay signal, results in correct userspace timers */
os_alarm_process(get_current()->mm->context.id.u.pid);
}
+#endif
(*timer_clockevent.event_handler)(&timer_clockevent);
diff --git a/arch/um/nommu/include/asm/cpu.h b/arch/um/nommu/include/asm/cpu.h
index c101c078ef21..c52a78c77bea 100644
--- a/arch/um/nommu/include/asm/cpu.h
+++ b/arch/um/nommu/include/asm/cpu.h
@@ -10,4 +10,7 @@ void lkl_cpu_wait_shutdown(void);
void lkl_cpu_change_owner(lkl_thread_t owner);
void lkl_cpu_set_irqs_pending(void);
+void nommu_irq_exit(void);
+int nommu_irq_enter(int sig);
+
#endif
diff --git a/arch/um/nommu/um/cpu.c b/arch/um/nommu/um/cpu.c
index 9986a3f8c5dd..75d8bdc1847e 100644
--- a/arch/um/nommu/um/cpu.c
+++ b/arch/um/nommu/um/cpu.c
@@ -8,15 +8,16 @@
#include <asm/sched.h>
#include <asm/syscalls.h>
#include <init.h>
+#include <os.h>
void run_irqs(void)
{
- panic("unimplemented %s", __func__);
+ unblock_signals();
}
-int set_irq_pending(int irq)
+void set_irq_pending(int sig)
{
- panic("unimplemented %s", __func__);
+ set_pending_signals(sig);
}
/*
@@ -174,6 +175,16 @@ int lkl_cpu_try_run_irq(int irq)
return ret;
}
+int nommu_irq_enter(int sig)
+{
+ return lkl_cpu_try_run_irq(sig);
+}
+
+void nommu_irq_exit(void)
+{
+ return lkl_cpu_put();
+}
+
static void lkl_cpu_shutdown(void)
{
__sync_fetch_and_add(&cpu.shutdown_gate, MAX_THREADS);
diff --git a/arch/um/nommu/um/setup.c b/arch/um/nommu/um/setup.c
index 25aa003792d4..f74baea50bd3 100644
--- a/arch/um/nommu/um/setup.c
+++ b/arch/um/nommu/um/setup.c
@@ -36,6 +36,8 @@ static void __init *lkl_run_kernel(void *arg)
panic_blink = lkl_panic_blink;
+ /* signal should be received at this thread (main and idle threads) */
+ init_new_thread_signals();
threads_init();
lkl_cpu_get();
start_kernel();
@@ -58,6 +60,9 @@ int __init lkl_start_kernel(struct lkl_host_operations *ops,
if (ret)
goto out_free_init_sem;
+ change_sig(SIGALRM, 0);
+ change_sig(SIGIO, 0);
+
ret = lkl_ops->thread_create(lkl_run_kernel, NULL);
if (!ret) {
ret = -ENOMEM;
diff --git a/arch/um/nommu/um/threads.c b/arch/um/nommu/um/threads.c
index 3e70eccc191a..df96057100fd 100644
--- a/arch/um/nommu/um/threads.c
+++ b/arch/um/nommu/um/threads.c
@@ -151,6 +151,9 @@ static void *thread_bootstrap(void *_tba)
int (*f)(void *) = tba->f;
void *arg = tba->arg;
+ change_sig(SIGALRM, 0);
+ change_sig(SIGIO, 0);
+
lkl_ops->sem_down(ti->task->thread.arch.sched_sem);
kfree(tba);
if (ti->task->thread.prev_sched)
diff --git a/tools/um/uml/signal.c b/tools/um/uml/signal.c
index b58bc68cbe64..2b5c98de21cd 100644
--- a/tools/um/uml/signal.c
+++ b/tools/um/uml/signal.c
@@ -218,8 +218,8 @@ void set_handler(int sig)
sigemptyset(&sig_mask);
sigaddset(&sig_mask, sig);
- if (sigprocmask(SIG_UNBLOCK, &sig_mask, NULL) < 0)
- panic("sigprocmask failed - errno = %d\n", errno);
+ if (pthread_sigmask(SIG_UNBLOCK, &sig_mask, NULL) < 0)
+ panic("pthread_sigmask failed - errno = %d\n", errno);
}
int change_sig(int signal, int on)
@@ -355,3 +355,11 @@ int os_is_signal_stack(void)
return ss.ss_flags & SS_ONSTACK;
}
+
+void set_pending_signals(int sig)
+{
+ if (sig == SIGIO)
+ signals_pending |= SIGIO_MASK;
+ else if (sig == SIGALRM)
+ signals_pending |= SIGALRM_MASK;
+}
--
2.21.0 (Apple Git-122.2)
