diff options
| author | Andrew Murray <andrew.murray@arm.com> | 2019-04-09 10:52:40 +0100 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2019-04-16 16:27:12 +0100 |
| commit | aaba098fe6ce594ae6f963dc041be6307e499f19 (patch) | |
| tree | 619d471f27d373e460f251afacddc19889dafe5c /drivers/clocksource | |
| parent | a823c35ff2eda73046cc1847326071de350fceda (diff) | |
| download | linux-aaba098fe6ce594ae6f963dc041be6307e499f19.tar.bz2 | |
arm64: HWCAP: add support for AT_HWCAP2
As we will exhaust the first 32 bits of AT_HWCAP let's start
exposing AT_HWCAP2 to userspace to give us up to 64 caps.
Whilst it's possible to use the remaining 32 bits of AT_HWCAP, we
prefer to expand into AT_HWCAP2 in order to provide a consistent
view to userspace between ILP32 and LP64. However internal to the
kernel we prefer to continue to use the full space of elf_hwcap.
To reduce complexity and allow for future expansion, we now
represent hwcaps in the kernel as ordinals and use a
KERNEL_HWCAP_ prefix. This allows us to support automatic feature
based module loading for all our hwcaps.
We introduce cpu_set_feature to set hwcaps which complements the
existing cpu_have_feature helper. These helpers allow us to clean
up existing direct uses of elf_hwcap and reduce any future effort
required to move beyond 64 caps.
For convenience we also introduce cpu_{have,set}_named_feature which
makes use of the cpu_feature macro to allow providing a hwcap name
without a {KERNEL_}HWCAP_ prefix.
Signed-off-by: Andrew Murray <andrew.murray@arm.com>
[will: use const_ilog2() and tweak documentation]
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'drivers/clocksource')
| -rw-r--r-- | drivers/clocksource/arm_arch_timer.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index aa4ec53281ce..6cc8aff83805 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -833,7 +833,11 @@ static void arch_timer_evtstrm_enable(int divider) cntkctl |= (divider << ARCH_TIMER_EVT_TRIGGER_SHIFT) | ARCH_TIMER_VIRT_EVT_EN; arch_timer_set_cntkctl(cntkctl); +#ifdef CONFIG_ARM64 + cpu_set_named_feature(EVTSTRM); +#else elf_hwcap |= HWCAP_EVTSTRM; +#endif #ifdef CONFIG_COMPAT compat_elf_hwcap |= COMPAT_HWCAP_EVTSTRM; #endif @@ -1055,7 +1059,11 @@ static int arch_timer_cpu_pm_notify(struct notifier_block *self, } else if (action == CPU_PM_ENTER_FAILED || action == CPU_PM_EXIT) { arch_timer_set_cntkctl(__this_cpu_read(saved_cntkctl)); +#ifdef CONFIG_ARM64 + if (cpu_have_named_feature(EVTSTRM)) +#else if (elf_hwcap & HWCAP_EVTSTRM) +#endif cpumask_set_cpu(smp_processor_id(), &evtstrm_available); } return NOTIFY_OK; |