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[PATCH 07/29] arm64: arch_timer: Add erratum handler for CPU-specific capability

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From: Marc Zyngier <marc.zyngier@arm.com>

Should we ever have a workaround for an erratum that is detected using
a capability and affecting a particular CPU, it'd be nice to have
a way to probe them directly.

Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/include/asm/arch_timer.h  |  1 +
 drivers/clocksource/arm_arch_timer.c | 28 ++++++++++++++++++++++++----
 2 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h
index 5cd964e..1b0d7e9 100644
--- a/arch/arm64/include/asm/arch_timer.h
+++ b/arch/arm64/include/asm/arch_timer.h
@@ -39,6 +39,7 @@ extern struct static_key_false arch_timer_read_ool_enabled;
 
 enum arch_timer_erratum_match_type {
 	ate_match_dt,
+	ate_match_local_cap_id,
 };
 
 struct arch_timer_erratum_workaround {
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 5c5c2af..532e47fa 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -214,6 +214,13 @@ bool arch_timer_check_dt_erratum(const struct arch_timer_erratum_workaround *wa,
 	return of_property_read_bool(np, wa->id);
 }
 
+static
+bool arch_timer_check_local_cap_erratum(const struct arch_timer_erratum_workaround *wa,
+					const void *arg)
+{
+	return this_cpu_has_cap((uintptr_t)wa->id);
+}
+
 static const struct arch_timer_erratum_workaround *
 arch_timer_iterate_errata(enum arch_timer_erratum_match_type type,
 			  ate_match_fn_t match_fn,
@@ -244,14 +251,16 @@ static void arch_timer_check_ool_workaround(enum arch_timer_erratum_match_type t
 {
 	const struct arch_timer_erratum_workaround *wa;
 	ate_match_fn_t match_fn = NULL;
-
-	if (static_branch_unlikely(&arch_timer_read_ool_enabled))
-		return;
+	bool local = false;
 
 	switch (type) {
 	case ate_match_dt:
 		match_fn = arch_timer_check_dt_erratum;
 		break;
+	case ate_match_local_cap_id:
+		match_fn = arch_timer_check_local_cap_erratum;
+		local = true;
+		break;
 	default:
 		WARN_ON(1);
 		return;
@@ -261,8 +270,17 @@ static void arch_timer_check_ool_workaround(enum arch_timer_erratum_match_type t
 	if (!wa)
 		return;
 
+	if (needs_unstable_timer_counter_workaround()) {
+		if (wa != timer_unstable_counter_workaround)
+			pr_warn("Can't enable workaround for %s (clashes with %s\n)",
+				wa->desc,
+				timer_unstable_counter_workaround->desc);
+		return;
+	}
+
 	arch_timer_enable_workaround(wa);
-	pr_info("Enabling global workaround for %s\n", wa->desc);
+	pr_info("Enabling %s workaround for %s\n",
+		local ? "local" : "global", wa->desc);
 }
 
 #else
@@ -522,6 +540,8 @@ static void __arch_timer_setup(unsigned type,
 			BUG();
 		}
 
+		arch_timer_check_ool_workaround(ate_match_local_cap_id, NULL);
+
 		erratum_workaround_set_sne(clk);
 	} else {
 		clk->features |= CLOCK_EVT_FEAT_DYNIRQ;
-- 
2.7.4

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[GIT PULL] timers changes for 4.12 Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-04-16 22:30 +0200
  [PATCH 18/29] arm64: arch_timer: Add HISILICON_ERRATUM_161010101 ACPI matching data Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-04-16 22:30 +0200
  [PATCH 22/29] dt-bindings: Clarify compatible property for rockchip timers Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-04-16 22:30 +0200
    Re: [PATCH 22/29] dt-bindings: Clarify compatible property for  rockchip timers Rob Herring <robh@kernel.org> - 2017-04-20 16:20 +0200
  [PATCH 07/29] arm64: arch_timer: Add erratum handler for CPU-specific capability Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-04-16 22:30 +0200
  [PATCH 29/29] clocksource/drivers/fttmr010: Refactor to handle clock Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-04-16 22:30 +0200
  [PATCH 11/29] arm64: arch_timer: Make workaround methods optional Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-04-16 22:30 +0200
  [PATCH 04/29] arm64: cpu_errata: Allow an erratum to be match for all revisions of a core Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-04-16 22:30 +0200
  [PATCH 13/29] arm64: arch_timer: Move clocksource_counter and co around Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-04-16 22:30 +0200
  [PATCH 27/29] clocksource: Augment bindings for Faraday timer Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-04-16 22:30 +0200
  [PATCH 01/29] arm64: Allow checking of a CPU-local erratum Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-04-16 22:30 +0200
    [PATCH 23/29] ARM: dts: rockchip: Update compatible property for rk322x timer Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-04-16 22:30 +0200
    [PATCH 05/29] arm64: cpu_errata: Add capability to advertise Cortex-A73 erratum 858921 Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-04-16 22:40 +0200
    [PATCH 02/29] arm64: Add CNTVCT_EL0 trap handler Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-04-16 22:40 +0200
    [PATCH 17/29] arm64: arch_timer: Allow erratum matching with ACPI OEM information Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-04-16 22:40 +0200
    [PATCH 08/29] arm64: arch_timer: Move arch_timer_reg_read/write around Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-04-16 22:40 +0200
    [PATCH 15/29] arm64: arch_timer: Enable CNTVCT_EL0 trap if workaround is enabled Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-04-16 22:40 +0200
    [PATCH 03/29] arm64: Define Cortex-A73 MIDR Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-04-16 22:40 +0200
    [PATCH 10/29] arm64: arch_timer: Rework the set_next_event workarounds Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-04-16 22:40 +0200
    [PATCH 26/29] ARM: dts: rockchip: disable arm-global-timer for rk3188 Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-04-16 22:40 +0200
    [PATCH 25/29] ARM: dts: rockchip: Add timer entries to rk3188 SoC Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-04-16 22:40 +0200
    [PATCH 09/29] arm64: arch_timer: Get rid of erratum_workaround_set_sne Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-04-16 22:40 +0200
    [PATCH 21/29] clocksource: Add missing line break to error messages Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-04-16 22:40 +0200
      Re: [PATCH 21/29] clocksource: Add missing line break to error  messages Uwe Kleine-König          <u.kleine-koenig@pengutronix.de> - 2017-04-24 09:50 +0200
    [PATCH 19/29] clocksource/drivers/orion: Read clock rate once Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-04-16 22:40 +0200

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