[PATCH 5/7] clocksource/arm_arch_timer: Drop use of static key in arch_timer_reg_read_stable

From: Marc Zyngier
Date: Mon Apr 08 2019 - 11:49:54 EST


Let's start with the removal of the arch_timer_read_ool_enabled
static key in arch_timer_reg_read_stable. IT is not a fast path,
and we can simplify things a bit.

Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
arch/arm64/include/asm/arch_timer.h | 42 +++++++++++++++++++----------
1 file changed, 28 insertions(+), 14 deletions(-)

diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h
index c3762ffcc933..4a06d46def7e 100644
--- a/arch/arm64/include/asm/arch_timer.h
+++ b/arch/arm64/include/asm/arch_timer.h
@@ -77,23 +77,37 @@ struct arch_timer_erratum_workaround {
DECLARE_PER_CPU(const struct arch_timer_erratum_workaround *,
timer_unstable_counter_workaround);

+/* inline sysreg accessors that make erratum_handler() work */
+static inline notrace u32 arch_timer_read_cntp_tval_el0(void)
+{
+ return read_sysreg(cntp_tval_el0);
+}
+
+static inline notrace u32 arch_timer_read_cntv_tval_el0(void)
+{
+ return read_sysreg(cntv_tval_el0);
+}
+
+static inline notrace u64 arch_timer_read_cntpct_el0(void)
+{
+ return read_sysreg(cntpct_el0);
+}
+
+static inline notrace u64 arch_timer_read_cntvct_el0(void)
+{
+ return read_sysreg(cntvct_el0);
+}
+
#define arch_timer_reg_read_stable(reg) \
-({ \
- u64 _val; \
- if (needs_unstable_timer_counter_workaround()) { \
- const struct arch_timer_erratum_workaround *wa; \
+ ({ \
+ u64 _val; \
+ \
preempt_disable_notrace(); \
- wa = __this_cpu_read(timer_unstable_counter_workaround); \
- if (wa && wa->read_##reg) \
- _val = wa->read_##reg(); \
- else \
- _val = read_sysreg(reg); \
+ _val = erratum_handler(read_ ## reg)(); \
preempt_enable_notrace(); \
- } else { \
- _val = read_sysreg(reg); \
- } \
- _val; \
-})
+ \
+ _val; \
+ })

/*
* These register accessors are marked inline so the compiler can
--
2.20.1