[PATCH 1/3] clocksource/arm_arch_timer: mark arch_counter_get_* as notrace

[PATCH 1/3] clocksource/arm_arch_timer: mark arch_counter_get_* as notrace

[Anders Roxell]

When CONFIG_FUNCTION_GRAPH_TRACER is enabled we end up in this circular
call trace since function arch_counter_get_cntvct() isn't marked with no
trace:

[   17.914934] Call trace:
[   17.915211]  ftrace_return_to_handler+0x194/0x288
[   17.915551]  return_to_handler+0x1c/0x38
[   17.915855]  trace_clock_local+0x38/0x88
[   17.916159]  function_graph_enter+0xf0/0x258
[   17.916465]  prepare_ftrace_return+0x60/0x90
[   17.916772]  ftrace_graph_caller+0x1c/0x24
[   17.917093]  arch_counter_get_cntvct+0x10/0x30
[   17.917417]  sched_clock+0x70/0x218
[   17.917723]  trace_clock_local+0x38/0x88
[   17.918026]  function_graph_enter+0xf0/0x258
[   17.918332]  prepare_ftrace_return+0x60/0x90
[   17.918649]  ftrace_graph_caller+0x1c/0x24
[   17.918963]  arch_counter_get_cntvct+0x10/0x30
[   17.919286]  sched_clock+0x70/0x218

Rework so that function arch_counter_get_cntvct() is marked with notrace.

Fixes: 0ea415390cd3 ("clocksource/arm_arch_timer: Use arch_timer_read_counter to access stable counters")
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
---
 drivers/clocksource/arm_arch_timer.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index b2a951a798e2..f4d5bd8fe906 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -149,22 +149,22 @@ u32 arch_timer_reg_read(int access, enum arch_timer_reg reg,
 	return val;
 }
 
-static u64 arch_counter_get_cntpct_stable(void)
+static u64 notrace arch_counter_get_cntpct_stable(void)
 {
 	return __arch_counter_get_cntpct_stable();
 }
 
-static u64 arch_counter_get_cntpct(void)
+static u64 notrace arch_counter_get_cntpct(void)
 {
 	return __arch_counter_get_cntpct();
 }
 
-static u64 arch_counter_get_cntvct_stable(void)
+static u64 notrace arch_counter_get_cntvct_stable(void)
 {
 	return __arch_counter_get_cntvct_stable();
 }
 
-static u64 arch_counter_get_cntvct(void)
+static u64 notrace arch_counter_get_cntvct(void)
 {
 	return __arch_counter_get_cntvct();
 }
@@ -947,7 +947,7 @@ bool arch_timer_evtstrm_available(void)
 	return cpumask_test_cpu(raw_smp_processor_id(), &evtstrm_available);
 }
 
-static u64 arch_counter_get_cntvct_mem(void)
+static u64 notrace arch_counter_get_cntvct_mem(void)
 {
 	u32 vct_lo, vct_hi, tmp_hi;
 
-- 
2.20.1

Re: [PATCH 1/3] clocksource/arm_arch_timer: mark arch_counter_get_* as notrace

[Marc Zyngier]

Hi Anders,


On 03/06/2019 10:12, Anders Roxell wrote:
> When CONFIG_FUNCTION_GRAPH_TRACER is enabled we end up in this circular
> call trace since function arch_counter_get_cntvct() isn't marked with no
> trace:
> 
> [   17.914934] Call trace:
> [   17.915211]  ftrace_return_to_handler+0x194/0x288
> [   17.915551]  return_to_handler+0x1c/0x38
> [   17.915855]  trace_clock_local+0x38/0x88
> [   17.916159]  function_graph_enter+0xf0/0x258
> [   17.916465]  prepare_ftrace_return+0x60/0x90
> [   17.916772]  ftrace_graph_caller+0x1c/0x24
> [   17.917093]  arch_counter_get_cntvct+0x10/0x30
> [   17.917417]  sched_clock+0x70/0x218
> [   17.917723]  trace_clock_local+0x38/0x88
> [   17.918026]  function_graph_enter+0xf0/0x258
> [   17.918332]  prepare_ftrace_return+0x60/0x90
> [   17.918649]  ftrace_graph_caller+0x1c/0x24
> [   17.918963]  arch_counter_get_cntvct+0x10/0x30
> [   17.919286]  sched_clock+0x70/0x218
> 
> Rework so that function arch_counter_get_cntvct() is marked with notrace.
> 
> Fixes: 0ea415390cd3 ("clocksource/arm_arch_timer: Use arch_timer_read_counter to access stable counters")
> Signed-off-by: Anders Roxell <anders.roxell@linaro.org>

This has already been queued by Daniel, I believe [1].

[1] https://lore.kernel.org/lkml/1558689025-50679-1-git-send-email-julien.thierry@arm.com/

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...

Re: [PATCH 1/3] clocksource/arm_arch_timer: mark arch_counter_get_* as notrace

[Daniel Lezcano]

Hi Anders,

thanks for your patch. As mentioned by Mark I already applied this fix
from Julien Thierry.

 -- Daniel


On 03/06/2019 11:23, Marc Zyngier wrote:
> Hi Anders,
> 
> 
> On 03/06/2019 10:12, Anders Roxell wrote:
>> When CONFIG_FUNCTION_GRAPH_TRACER is enabled we end up in this circular
>> call trace since function arch_counter_get_cntvct() isn't marked with no
>> trace:
>>
>> [   17.914934] Call trace:
>> [   17.915211]  ftrace_return_to_handler+0x194/0x288
>> [   17.915551]  return_to_handler+0x1c/0x38
>> [   17.915855]  trace_clock_local+0x38/0x88
>> [   17.916159]  function_graph_enter+0xf0/0x258
>> [   17.916465]  prepare_ftrace_return+0x60/0x90
>> [   17.916772]  ftrace_graph_caller+0x1c/0x24
>> [   17.917093]  arch_counter_get_cntvct+0x10/0x30
>> [   17.917417]  sched_clock+0x70/0x218
>> [   17.917723]  trace_clock_local+0x38/0x88
>> [   17.918026]  function_graph_enter+0xf0/0x258
>> [   17.918332]  prepare_ftrace_return+0x60/0x90
>> [   17.918649]  ftrace_graph_caller+0x1c/0x24
>> [   17.918963]  arch_counter_get_cntvct+0x10/0x30
>> [   17.919286]  sched_clock+0x70/0x218
>>
>> Rework so that function arch_counter_get_cntvct() is marked with notrace.
>>
>> Fixes: 0ea415390cd3 ("clocksource/arm_arch_timer: Use arch_timer_read_counter to access stable counters")
>> Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
> 
> This has already been queued by Daniel, I believe [1].
> 
> [1] https://lore.kernel.org/lkml/1558689025-50679-1-git-send-email-julien.thierry@arm.com/





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