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[PATCH v3 07/18] arm64: arch_timer: Add erratum handler for CPU-specific capability

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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.

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 5cd964e90d11..1b0d7e994e0c 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 5c5c2af74ad9..532e47fa43b3 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;
-- 
2.11.0

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[PATCH v3 00/18] clocksource/arch_timer: Errata workaround infrastructure rework Marc Zyngier <marc.zyngier@arm.com> - 2017-04-04 19:20 +0200
  [PATCH v3 06/18] arm64: arch_timer: Add infrastructure for multiple erratum detection methods Marc Zyngier <marc.zyngier@arm.com> - 2017-04-04 19:20 +0200
  [PATCH v3 02/18] arm64: Add CNTVCT_EL0 trap handler Marc Zyngier <marc.zyngier@arm.com> - 2017-04-04 19:20 +0200
  [PATCH v3 18/18] arm64: arch_timer: Add HISILICON_ERRATUM_161010101 ACPI matching data Marc Zyngier <marc.zyngier@arm.com> - 2017-04-04 19:20 +0200
  [PATCH v3 17/18] arm64: arch_timer: Allow erratum matching with ACPI OEM information Marc Zyngier <marc.zyngier@arm.com> - 2017-04-04 19:20 +0200
  [PATCH v3 15/18] arm64: arch_timer: Enable CNTVCT_EL0 trap if workaround is enabled Marc Zyngier <marc.zyngier@arm.com> - 2017-04-04 19:20 +0200
  [PATCH v3 12/18] arm64: arch_timer: Allows a CPU-specific erratum to only affect a subset of CPUs Marc Zyngier <marc.zyngier@arm.com> - 2017-04-04 19:20 +0200
  [PATCH v3 03/18] arm64: Define Cortex-A73 MIDR Marc Zyngier <marc.zyngier@arm.com> - 2017-04-04 19:30 +0200
  [PATCH v3 09/18] arm64: arch_timer: Get rid of erratum_workaround_set_sne Marc Zyngier <marc.zyngier@arm.com> - 2017-04-04 19:30 +0200
  [PATCH v3 13/18] arm64: arch_timer: Move clocksource_counter and co around Marc Zyngier <marc.zyngier@arm.com> - 2017-04-04 19:30 +0200
  [PATCH v3 14/18] arm64: arch_timer: Save cntkctl_el1 as a per-cpu variable Marc Zyngier <marc.zyngier@arm.com> - 2017-04-04 19:30 +0200
  [PATCH v3 07/18] arm64: arch_timer: Add erratum handler for CPU-specific capability Marc Zyngier <marc.zyngier@arm.com> - 2017-04-04 19:30 +0200
  [PATCH v3 11/18] arm64: arch_timer: Make workaround methods optional Marc Zyngier <marc.zyngier@arm.com> - 2017-04-04 19:30 +0200
  [PATCH v3 01/18] arm64: Allow checking of a CPU-local erratum Marc Zyngier <marc.zyngier@arm.com> - 2017-04-04 19:30 +0200
  [PATCH v3 16/18] arm64: arch_timer: Workaround for Cortex-A73 erratum 858921 Marc Zyngier <marc.zyngier@arm.com> - 2017-04-04 19:30 +0200
  [PATCH v3 10/18] arm64: arch_timer: Rework the set_next_event workarounds Marc Zyngier <marc.zyngier@arm.com> - 2017-04-04 19:30 +0200
  [PATCH v3 08/18] arm64: arch_timer: Move arch_timer_reg_read/write around Marc Zyngier <marc.zyngier@arm.com> - 2017-04-04 19:30 +0200
  Re: [PATCH v3 00/18] clocksource/arch_timer: Errata workaround  infrastructure rework Catalin Marinas <catalin.marinas@arm.com> - 2017-04-06 18:30 +0200
    Re: [PATCH v3 00/18] clocksource/arch_timer: Errata workaround  infrastructure rework Thomas Gleixner <tglx@linutronix.de> - 2017-04-07 10:20 +0200

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