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 16/18] arm64: arch_timer: Workaround for Cortex-A73 erratum 858921
Date: Mon, 20 Mar 2017 17:48:27 +0000 [thread overview]
Message-ID: <20170320174829.28182-17-marc.zyngier@arm.com> (raw)
In-Reply-To: <20170320174829.28182-1-marc.zyngier@arm.com>
Cortex-A73 (all versions) counter read can return a wrong value
when the counter crosses a 32bit boundary.
The workaround involves performing the read twice, and to return
one or the other depending on whether a transition has taken place.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
drivers/clocksource/Kconfig | 11 +++++++++++
drivers/clocksource/arm_arch_timer.c | 19 +++++++++++++++++++
2 files changed, 30 insertions(+)
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 3356ab821624..af80a7c44faf 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -366,6 +366,17 @@ config HISILICON_ERRATUM_161010101
161010101. The workaround will be active if the hisilicon,erratum-161010101
property is found in the timer node.
+config ARM64_ERRATUM_858921
+ bool "Workaround for Cortex-A73 erratum 858921"
+ default y
+ select ARM_ARCH_TIMER_OOL_WORKAROUND
+ depends on ARM_ARCH_TIMER && ARM64
+ help
+ This option enables a workaround applicable to Cortex-A73
+ (all versions), whose counter may return incorrect values.
+ The workaround will be dynamically enabled when an affected
+ core is detected.
+
config ARM_GLOBAL_TIMER
bool "Support for the ARM global timer" if COMPILE_TEST
select CLKSRC_OF if OF
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index eccff0fedf2c..ba4be5859aa4 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -266,6 +266,17 @@ static u64 notrace hisi_161010101_read_cntvct_el0(void)
}
#endif
+#ifdef CONFIG_ARM64_ERRATUM_858921
+static u64 notrace arm64_858921_read_cntvct_el0(void)
+{
+ u64 old, new;
+
+ old = read_sysreg(cntvct_el0);
+ new = read_sysreg(cntvct_el0);
+ return (((old ^ new) >> 32) & 1) ? old : new;
+}
+#endif
+
#ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
DEFINE_PER_CPU(const struct arch_timer_erratum_workaround *,
timer_unstable_counter_workaround);
@@ -331,6 +342,14 @@ static const struct arch_timer_erratum_workaround ool_workarounds[] = {
.set_next_event_virt = erratum_set_next_event_tval_virt,
},
#endif
+#ifdef CONFIG_ARM64_ERRATUM_858921
+ {
+ .match_type = ate_match_local_cap_id,
+ .id = (void *)ARM64_WORKAROUND_858921,
+ .desc = "ARM erratum 858921",
+ .read_cntvct_el0 = arm64_858921_read_cntvct_el0,
+ },
+#endif
};
typedef bool (*ate_match_fn_t)(const struct arch_timer_erratum_workaround *,
--
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 ` [PATCH v2 13/18] arm64: arch_timer: Allows a CPU-specific erratum to only affect a subset of CPUs Marc Zyngier
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 ` Marc Zyngier [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20170320174829.28182-17-marc.zyngier@arm.com \
--to=marc.zyngier@arm.com \
--cc=catalin.marinas@arm.com \
--cc=daniel.lezcano@linaro.org \
--cc=dann.frazier@canonical.com \
--cc=dingtianhong@huawei.com \
--cc=hanjun.guo@linaro.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=oss@buserror.net \
--cc=will.deacon@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).