From: Marc Zyngier <marc.zyngier@arm.com>
To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Cc: Mark Rutland <mark.rutland@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Will Deacon <will.deacon@arm.com>, Scott Wood <oss@buserror.net>,
Hanjun Guo <hanjun.guo@linaro.org>,
Ding Tianhong <dingtianhong@huawei.com>,
dann frazier <dann.frazier@canonical.com>
Subject: [PATCH v2 13/18] arm64: arch_timer: Allows a CPU-specific erratum to only affect a subset of CPUs
Date: Mon, 20 Mar 2017 17:48:24 +0000 [thread overview]
Message-ID: <20170320174829.28182-14-marc.zyngier@arm.com> (raw)
In-Reply-To: <20170320174829.28182-1-marc.zyngier@arm.com>
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.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
arch/arm64/include/asm/arch_timer.h | 31 ++++++++++++++++----------
drivers/clocksource/arm_arch_timer.c | 42 +++++++++++++++++++++++++-----------
2 files changed, 50 insertions(+), 23 deletions(-)
diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h
index d46cf21e8b80..3cba3a5e4ba1 100644
--- a/arch/arm64/include/asm/arch_timer.h
+++ b/arch/arm64/include/asm/arch_timer.h
@@ -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>
@@ -56,17 +57,25 @@ 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;
-
-#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; \
+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()) { \
+ 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; \
})
/*
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index b9f01daafdfa..2b17b99922a1 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -235,7 +235,8 @@ static u64 notrace hisi_161010101_read_cntvct_el0(void)
#endif
#ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
-const struct arch_timer_erratum_workaround *timer_unstable_counter_workaround = NULL;
+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);
@@ -345,9 +346,18 @@ arch_timer_iterate_errata(enum arch_timer_erratum_match_type type,
}
static
-void arch_timer_enable_workaround(const struct arch_timer_erratum_workaround *wa)
+void arch_timer_enable_workaround(const struct arch_timer_erratum_workaround *wa,
+ bool local)
{
- timer_unstable_counter_workaround = wa;
+ int i;
+
+ if (local) {
+ __this_cpu_write(timer_unstable_counter_workaround, wa);
+ } else {
+ for_each_possible_cpu(i)
+ per_cpu(timer_unstable_counter_workaround, i) = wa;
+ }
+
static_branch_enable(&arch_timer_read_ool_enabled);
}
@@ -376,14 +386,17 @@ static void arch_timer_check_ool_workaround(enum arch_timer_erratum_match_type t
return;
if (static_branch_unlikely(&arch_timer_read_ool_enabled)) {
- if (wa != timer_unstable_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,
- timer_unstable_counter_workaround->desc);
- return;
+ wa->desc, __wa->desc);
+
+ if (__wa)
+ return;
}
- arch_timer_enable_workaround(wa);
+ arch_timer_enable_workaround(wa, local);
pr_info("Enabling %s workaround for %s\n",
local ? "local" : "global", wa->desc);
}
@@ -391,10 +404,15 @@ static void arch_timer_check_ool_workaround(enum arch_timer_erratum_match_type t
#define erratum_handler(fn, r, ...) \
({ \
bool __val; \
- if (needs_unstable_timer_counter_workaround() && \
- timer_unstable_counter_workaround->fn) { \
- r = timer_unstable_counter_workaround->fn(__VA_ARGS__); \
- __val = true; \
+ if (needs_unstable_timer_counter_workaround()) { \
+ const struct arch_timer_erratum_workaround *__wa; \
+ __wa = __this_cpu_read(timer_unstable_counter_workaround); \
+ if (__wa && __wa->fn) { \
+ r = __wa->fn(__VA_ARGS__); \
+ __val = true; \
+ } else { \
+ __val = false; \
+ } \
} else { \
__val = false; \
} \
--
2.11.0
next prev parent reply other threads:[~2017-03-20 18:39 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-20 17:48 [PATCH v2 00/18] clocksource/arch_timer: Errata workaround infrastructure rework Marc Zyngier
2017-03-20 17:48 ` [PATCH v2 01/18] arm64: Allow checking of a CPU-local erratum Marc Zyngier
2017-03-22 9:22 ` Daniel Lezcano
2017-03-20 17:48 ` [PATCH v2 02/18] arm64: Add CNTVCT_EL0 trap handler Marc Zyngier
2017-03-20 17:48 ` [PATCH v2 03/18] arm64: Define Cortex-A73 MIDR Marc Zyngier
2017-03-20 17:48 ` [PATCH v2 04/18] arm64: cpu_errata: Allow an erratum to be match for all revisions of a core Marc Zyngier
2017-03-22 14:57 ` Daniel Lezcano
2017-03-20 17:48 ` [PATCH v2 05/18] arm64: cpu_errata: Add capability to advertise Cortex-A73 erratum 858921 Marc Zyngier
2017-03-22 15:01 ` Daniel Lezcano
2017-03-20 17:48 ` [PATCH v2 06/18] arm64: arch_timer: Add infrastructure for multiple erratum detection methods Marc Zyngier
2017-03-22 15:41 ` Daniel Lezcano
2017-03-22 15:53 ` Marc Zyngier
2017-03-22 15:59 ` Marc Zyngier
2017-03-22 16:52 ` Daniel Lezcano
2017-03-23 17:30 ` Daniel Lezcano
2017-03-24 13:51 ` Marc Zyngier
2017-03-27 7:56 ` Daniel Lezcano
2017-03-28 13:07 ` Marc Zyngier
2017-03-28 13:34 ` Daniel Lezcano
2017-03-28 14:07 ` Marc Zyngier
2017-03-28 14:36 ` Daniel Lezcano
2017-03-28 14:48 ` Marc Zyngier
2017-03-28 14:55 ` Daniel Lezcano
2017-03-28 15:38 ` Marc Zyngier
2017-03-29 14:27 ` Daniel Lezcano
2017-03-29 14:56 ` Marc Zyngier
2017-03-29 15:12 ` Daniel Lezcano
2017-03-24 17:48 ` dann frazier
2017-03-24 18:00 ` Marc Zyngier
2017-03-30 9:28 ` Daniel Lezcano
2017-03-20 17:48 ` [PATCH v2 07/18] arm64: arch_timer: Add erratum handler for globally defined capability Marc Zyngier
2017-03-20 17:48 ` [PATCH v2 08/18] arm64: arch_timer: Add erratum handler for CPU-specific capability Marc Zyngier
2017-03-20 17:48 ` [PATCH v2 09/18] arm64: arch_timer: Move arch_timer_reg_read/write around Marc Zyngier
2017-03-22 15:47 ` Daniel Lezcano
2017-03-20 17:48 ` [PATCH v2 10/18] arm64: arch_timer: Get rid of erratum_workaround_set_sne Marc Zyngier
2017-03-20 17:48 ` [PATCH v2 11/18] arm64: arch_timer: Rework the set_next_event workarounds Marc Zyngier
2017-03-20 17:48 ` [PATCH v2 12/18] arm64: arch_timer: Make workaround methods optional Marc Zyngier
2017-03-20 17:48 ` Marc Zyngier [this message]
2017-03-20 17:48 ` [PATCH v2 14/18] arm64: arch_timer: Move clocksource_counter and co around Marc Zyngier
2017-03-20 17:48 ` [PATCH v2 15/18] arm64: arch_timer: Enable CNTVCT_EL0 trap if workaround is enabled Marc Zyngier
2017-03-20 17:48 ` [PATCH v2 16/18] arm64: arch_timer: Workaround for Cortex-A73 erratum 858921 Marc Zyngier
2017-03-20 17:48 ` [PATCH v2 17/18] arm64: arch_timer: Allow erratum matching with ACPI OEM information Marc Zyngier
2017-03-20 17:48 ` [PATCH v2 18/18] arm64: arch_timer: Add HISILICON_ERRATUM_161010101 ACPI matching data Marc Zyngier
2017-03-22 13:56 ` [PATCH v2 00/18] clocksource/arch_timer: Errata workaround infrastructure rework Ding Tianhong
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