From aaba098fe6ce594ae6f963dc041be6307e499f19 Mon Sep 17 00:00:00 2001 From: Andrew Murray Date: Tue, 9 Apr 2019 10:52:40 +0100 Subject: 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 [will: use const_ilog2() and tweak documentation] Signed-off-by: Will Deacon --- drivers/clocksource/arm_arch_timer.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'drivers/clocksource') 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; -- cgit v1.2.3