The use of a static key in a hotplug path has proved to be a real nightmare, and makes it impossible to have scream-free lockdep kernel.
Let's remove the static key altogether, and focus on something saner. Signed-off-by: Marc Zyngier <[email protected]> --- arch/arm64/include/asm/arch_timer.h | 4 ---- drivers/clocksource/arm_arch_timer.c | 25 +++++++------------------ 2 files changed, 7 insertions(+), 22 deletions(-) diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h index 4a06d46def7e..5502ea049b63 100644 --- a/arch/arm64/include/asm/arch_timer.h +++ b/arch/arm64/include/asm/arch_timer.h @@ -45,13 +45,9 @@ (__wa && __wa->h) ? __wa->h : arch_timer_##h; \ }) -extern struct static_key_false arch_timer_read_ool_enabled; -#define needs_unstable_timer_counter_workaround() \ - static_branch_unlikely(&arch_timer_read_ool_enabled) #else #define has_erratum_handler(h) false #define erratum_handler(h) (arch_timer_##h) -#define needs_unstable_timer_counter_workaround() false #endif enum arch_timer_erratum_match_type { diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index c7f5b66d893c..da487fbfada3 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -372,8 +372,6 @@ static u32 notrace sun50i_a64_read_cntv_tval_el0(void) DEFINE_PER_CPU(const struct arch_timer_erratum_workaround *, timer_unstable_counter_workaround); EXPORT_SYMBOL_GPL(timer_unstable_counter_workaround); -DEFINE_STATIC_KEY_FALSE(arch_timer_read_ool_enabled); -EXPORT_SYMBOL_GPL(arch_timer_read_ool_enabled); static void erratum_set_next_event_tval_generic(const int access, unsigned long evt, struct clock_event_device *clk) @@ -552,12 +550,6 @@ void arch_timer_enable_workaround(const struct arch_timer_erratum_workaround *wa per_cpu(timer_unstable_counter_workaround, i) = wa; } - /* - * Use the locked version, as we're called from the CPU - * hotplug framework. Otherwise, we end-up in deadlock-land. - */ - static_branch_enable_cpuslocked(&arch_timer_read_ool_enabled); - /* * Don't use the vdso fastpath if errata require using the * out-of-line counter accessor. We may change our mind pretty @@ -573,7 +565,7 @@ void arch_timer_enable_workaround(const struct arch_timer_erratum_workaround *wa static void arch_timer_check_ool_workaround(enum arch_timer_erratum_match_type type, void *arg) { - const struct arch_timer_erratum_workaround *wa; + const struct arch_timer_erratum_workaround *wa, *__wa; ate_match_fn_t match_fn = NULL; bool local = false; @@ -597,16 +589,13 @@ static void arch_timer_check_ool_workaround(enum arch_timer_erratum_match_type t if (!wa) return; - if (needs_unstable_timer_counter_workaround()) { - const struct arch_timer_erratum_workaround *__wa; - __wa = __this_cpu_read(timer_unstable_counter_workaround); - if (__wa && wa != __wa) - pr_warn("Can't enable workaround for %s (clashes with %s\n)", - wa->desc, __wa->desc); + __wa = __this_cpu_read(timer_unstable_counter_workaround); + if (__wa && wa != __wa) + pr_warn("Can't enable workaround for %s (clashes with %s\n)", + wa->desc, __wa->desc); - if (__wa) - return; - } + if (__wa) + return; arch_timer_enable_workaround(wa, local); pr_info("Enabling %s workaround for %s\n", -- 2.20.1
