Re: [PATCH v4 2/5] irqchip, gicv3: Workaround for Cavium ThunderX erratum 23154
From: Suzuki K. Poulose
Date: Mon Sep 07 2015 - 12:54:19 EST
On 14/08/15 19:28, Robert Richter wrote:
From: Robert Richter <rrichter@xxxxxxxxxx>
This patch implements Cavium ThunderX erratum 23154.
The gicv3 of ThunderX requires a modified version for reading the IAR
status to ensure data synchronization. Since this is in the fast-path
and called with each interrupt, runtime patching is used using jump
label patching for smallest overhead (no-op). This is the same
technique as used for tracepoints.
v4:
* simplify code to only use cpus_have_cap() in gicv3_enable_quirks()
v3:
* fix erratum to be dependend from midr
* use arm64 errata framework
v2:
* implement code in a single asm() to keep instruction sequence
* added comment to the code that explains the erratum
* apply workaround also if running as guest, thus check MIDR
Signed-off-by: Robert Richter <rrichter@xxxxxxxxxx>
---
arch/arm64/Kconfig | 11 ++++++++++
arch/arm64/include/asm/cpufeature.h | 3 ++-
arch/arm64/include/asm/cputype.h | 18 +++++++++-------
arch/arm64/kernel/cpu_errata.c | 9 ++++++++
drivers/irqchip/irq-gic-v3.c | 42 ++++++++++++++++++++++++++++++++++++-
5 files changed, 74 insertions(+), 9 deletions(-)
...
};
diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index c52f7ba205b4..4211c39b8744 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -107,7 +107,7 @@ static void gic_redist_wait_for_rwp(void)
...
+}
+
static void __maybe_unused gic_write_pmr(u64 val)
{
asm volatile("msr_s " __stringify(ICC_PMR_EL1) ", %0" : : "r" (val));
@@ -766,6 +798,12 @@ static const struct irq_domain_ops gic_irq_domain_ops = {
.free = gic_irq_domain_free,
};
+static void gicv3_enable_quirks(void)
+{
+ if (cpus_have_cap(ARM64_WORKAROUND_CAVIUM_23154))
+ static_key_slow_inc(&is_cavium_thunderx);
May be you could use the enable() method added to struct arm64_cpu_capability
here to perform the above operation, added by James :
commit 1c0763037f1e1caef739e36e09c6d41ed7b61b2d
Author: James Morse <james.morse@xxxxxxx>
Date: Tue Jul 21 13:23:28 2015 +0100
arm64: kernel: Add cpufeature 'enable' callback
+}
+
static int __init gic_of_init(struct device_node *node, struct device_node *parent)
{
void __iomem *dist_base;
@@ -825,6 +863,8 @@ static int __init gic_of_init(struct device_node *node, struct device_node *pare
gic_data.nr_redist_regions = nr_redist_regions;
gic_data.redist_stride = redist_stride;
+ gicv3_enable_quirks();
+
than adding a hook here ?
Cheers
Suzuki
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