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arm64: arch_timer: Allows a CPU-specific erratum to only affect a subset of CPUs

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Instead of applying a CPU-specific workaround to all CPUs in the system,
allow it to only affect a subset of them (typical big-little case).

This is done by turning the erratum pointer into a per-CPU variable.

Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This commit is contained in:
Marc Zyngier
2017-02-20 18:34:48 +00:00
parent 8c64621bf9
commit 6acc71ccac
2 changed files with 49 additions and 22 deletions
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29
arch/arm64/include/asm/arch_timer.h
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@@ -25,6 +25,7 @@
#include <linux/bug.h>
#include <linux/init.h>
#include <linux/jump_label.h>
#include <linux/smp.h>
#include <linux/types.h>
#include <clocksource/arm_arch_timer.h>
@@ -55,17 +56,25 @@ struct arch_timer_erratum_workaround {
int (*set_next_event_virt)(unsigned long, struct clock_event_device *);
};
extern const struct arch_timer_erratum_workaround *timer_unstable_counter_workaround;
DECLARE_PER_CPU(const struct arch_timer_erratum_workaround *,
timer_unstable_counter_workaround);
#define arch_timer_reg_read_stable(reg) \
({ \
u64 _val; \
if (needs_unstable_timer_counter_workaround() && \
timer_unstable_counter_workaround->read_##reg) \
_val = timer_unstable_counter_workaround->read_##reg(); \
else \
_val = read_sysreg(reg); \
_val; \
#define arch_timer_reg_read_stable(reg) \
({ \
u64 _val; \
if (needs_unstable_timer_counter_workaround()) { \
const struct arch_timer_erratum_workaround *wa; \
preempt_disable(); \
wa = __this_cpu_read(timer_unstable_counter_workaround); \
if (wa && wa->read_##reg) \
_val = wa->read_##reg(); \
else \
_val = read_sysreg(reg); \
preempt_enable(); \
} else { \
_val = read_sysreg(reg); \
} \
_val; \
})
/*