Hi Frederic,
On 06/29/2017 06:28 AM, KONRAD Frederic wrote:
This helps the board developer by asserting that system_clock_rate is not
null. Using systick with a zero rate will lead to a deadlock so better showing
the error.
Signed-off-by: KONRAD Frederic <frederic.kon...@adacore.com>
---
hw/timer/armv7m_systick.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/hw/timer/armv7m_systick.c b/hw/timer/armv7m_systick.c
index df8d280..745efb7 100644
--- a/hw/timer/armv7m_systick.c
+++ b/hw/timer/armv7m_systick.c
@@ -54,6 +54,9 @@ static void systick_reload(SysTickState *s, int reset)
s->tick = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
}
s->tick += (s->reload + 1) * systick_scale(s);
+
+ /* system_clock_scale = 0 leads to a nasty deadlock, better aborting */
+ assert(systick_scale(s));
timer_mod(s->timer, s->tick);
}
This is true it is better to abort here than risking a deadlock.
However it seems to me they are 3 issues here:
- the deadlock pattern is caused by using a global variable,
- stellaris:ssys_calculate_system_clock() no checking RCC.SYSDIV and
RCC2.SYSDIV2 values <= 2 are reserved (GUEST_ERROR)
- stellaris:ssys_write(RCC2) not overrides correctly RCC
I'd rather take this opportunity to fix the deadlock pattern using a
getter/setter on system_clock_scale, doing the zero check in the setter
and eventually aborting in the getter, what do you think?
Regards,
Phil.
