| Message ID | 1407003407-31219-4-git-send-email-nathan_lynch@mentor.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 08/02/14 11:16, Nathan Lynch wrote: > The arm and arm64 VDSOs need CP15 access to the architected counter. > If this is unavailable (which is allowed by ARM v7), indicate this by > changing the clocksource name to "arch_mem_counter" before registering > the clocksource. > > Suggested by Stephen Boyd. > > Signed-off-by: Nathan Lynch <nathan_lynch@mentor.com> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
On Sun, Aug 3, 2014 at 3:16 AM, Nathan Lynch <nathan_lynch@mentor.com> wrote: > The arm and arm64 VDSOs need CP15 access to the architected counter. > If this is unavailable (which is allowed by ARM v7), indicate this by > changing the clocksource name to "arch_mem_counter" before registering > the clocksource. > > Suggested by Stephen Boyd. > > Signed-off-by: Nathan Lynch <nathan_lynch@mentor.com> > --- > drivers/clocksource/arm_arch_timer.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c > index 5163ec13429d..c99afdf12e98 100644 > --- a/drivers/clocksource/arm_arch_timer.c > +++ b/drivers/clocksource/arm_arch_timer.c > @@ -429,11 +429,19 @@ static void __init arch_counter_register(unsigned type) > u64 start_count; > > /* Register the CP15 based counter if we have one */ > - if (type & ARCH_CP15_TIMER) > + if (type & ARCH_CP15_TIMER) { > arch_timer_read_counter = arch_counter_get_cntvct; > - else > + } else { > arch_timer_read_counter = arch_counter_get_cntvct_mem; > > + /* If the clocksource name is "arch_sys_counter" the > + * VDSO will attempt to read the CP15-based counter. > + * Ensure this does not happen when CP15-based > + * counter is not available. > + */ > + clocksource_counter.name = "arch_mem_counter"; > + } > + > start_count = arch_timer_read_counter(); > clocksource_register_hz(&clocksource_counter, arch_timer_rate); > cyclecounter.mult = clocksource_counter.mult; > -- > 1.9.3 > FWIW, x86 does this using the archdata field in the clocksource, but I see nothing wrong with doing it this way instead. --Andy
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 5163ec13429d..c99afdf12e98 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -429,11 +429,19 @@ static void __init arch_counter_register(unsigned type) u64 start_count; /* Register the CP15 based counter if we have one */ - if (type & ARCH_CP15_TIMER) + if (type & ARCH_CP15_TIMER) { arch_timer_read_counter = arch_counter_get_cntvct; - else + } else { arch_timer_read_counter = arch_counter_get_cntvct_mem; + /* If the clocksource name is "arch_sys_counter" the + * VDSO will attempt to read the CP15-based counter. + * Ensure this does not happen when CP15-based + * counter is not available. + */ + clocksource_counter.name = "arch_mem_counter"; + } + start_count = arch_timer_read_counter(); clocksource_register_hz(&clocksource_counter, arch_timer_rate); cyclecounter.mult = clocksource_counter.mult;
The arm and arm64 VDSOs need CP15 access to the architected counter. If this is unavailable (which is allowed by ARM v7), indicate this by changing the clocksource name to "arch_mem_counter" before registering the clocksource. Suggested by Stephen Boyd. Signed-off-by: Nathan Lynch <nathan_lynch@mentor.com> --- drivers/clocksource/arm_arch_timer.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)