From: Mohamed Mediouni <mohamed.mediouni@caramail.com>
To: linux-arm-kernel@lists.infradead.org
Cc: Mark Rutland <mark.rutland@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Hector Martin <marcan@marcan.st>,
linux-kernel@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
Mohamed Mediouni <mohamed.mediouni@caramail.com>,
Will Deacon <will@kernel.org>,
Stan Skowronek <stan@corellium.com>
Subject: [RFC PATCH 2/7] arm64: kernel: Add a WFI hook.
Date: Wed, 20 Jan 2021 14:27:12 +0100 [thread overview]
Message-ID: <20210120132717.395873-3-mohamed.mediouni@caramail.com> (raw)
In-Reply-To: <20210120132717.395873-1-mohamed.mediouni@caramail.com>
From: Stan Skowronek <stan@corellium.com>
WFI drops register state on Apple Silicon for SMP systems.
This hook will be used for a hardware workaround in the
Apple CPU start driver.
Signed-off-by: Stan Skowronek <stan@corellium.com>
Signed-off-by: Mohamed Mediouni <mohamed.mediouni@caramail.com>
---
arch/arm64/include/asm/cpu_ops.h | 2 ++
arch/arm64/kernel/cpu_ops.c | 6 ++++++
arch/arm64/kernel/process.c | 11 +++++++++--
3 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/include/asm/cpu_ops.h b/arch/arm64/include/asm/cpu_ops.h
index e95c4df83911..4be0fc5bcaf9 100644
--- a/arch/arm64/include/asm/cpu_ops.h
+++ b/arch/arm64/include/asm/cpu_ops.h
@@ -23,6 +23,7 @@
* @cpu_boot: Boots a cpu into the kernel.
* @cpu_postboot: Optionally, perform any post-boot cleanup or necessary
* synchronisation. Called from the cpu being booted.
+ * @cpu_wfi: Optionally, replace calls to WFI in default idle with this.
* @cpu_can_disable: Determines whether a CPU can be disabled based on
* mechanism-specific information.
* @cpu_disable: Prepares a cpu to die. May fail for some mechanism-specific
@@ -43,6 +44,7 @@ struct cpu_operations {
int (*cpu_prepare)(unsigned int);
int (*cpu_boot)(unsigned int);
void (*cpu_postboot)(void);
+ void (*cpu_wfi)(void);
#ifdef CONFIG_HOTPLUG_CPU
bool (*cpu_can_disable)(unsigned int cpu);
int (*cpu_disable)(unsigned int cpu);
diff --git a/arch/arm64/kernel/cpu_ops.c b/arch/arm64/kernel/cpu_ops.c
index e133011f64b5..6979fc4490b2 100644
--- a/arch/arm64/kernel/cpu_ops.c
+++ b/arch/arm64/kernel/cpu_ops.c
@@ -19,12 +19,18 @@ extern const struct cpu_operations smp_spin_table_ops;
extern const struct cpu_operations acpi_parking_protocol_ops;
#endif
extern const struct cpu_operations cpu_psci_ops;
+#ifdef CONFIG_ARCH_APPLE
+extern const struct cpu_operations cpu_apple_start_ops;
+#endif
static const struct cpu_operations *cpu_ops[NR_CPUS] __ro_after_init;
static const struct cpu_operations *const dt_supported_cpu_ops[] __initconst = {
&smp_spin_table_ops,
&cpu_psci_ops,
+#ifdef CONFIG_ARCH_APPLE
+ &cpu_apple_start_ops,
+#endif
NULL,
};
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 34ec400288d0..611c639e20be 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -57,6 +57,7 @@
#include <asm/processor.h>
#include <asm/pointer_auth.h>
#include <asm/stacktrace.h>
+#include <asm/cpu_ops.h>
#if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK)
#include <linux/stackprotector.h>
@@ -74,8 +75,14 @@ void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
static void noinstr __cpu_do_idle(void)
{
- dsb(sy);
- wfi();
+ const struct cpu_operations *ops = get_cpu_ops(task_cpu(current));
+
+ if (ops->cpu_wfi) {
+ ops->cpu_wfi();
+ } else {
+ dsb(sy);
+ wfi();
+ }
}
static void noinstr __cpu_do_idle_irqprio(void)
--
2.29.2
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next prev parent reply other threads:[~2021-01-20 13:32 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-20 13:27 [RFC PATCH 0/7] Linux on Apple Silicon Mohamed Mediouni
2021-01-20 13:27 ` [RFC PATCH 1/7] arm64: kernel: FIQ support Mohamed Mediouni
2021-01-20 13:27 ` Mohamed Mediouni [this message]
2021-01-20 16:46 ` [RFC PATCH 2/7] arm64: kernel: Add a WFI hook Alexander Graf
[not found] ` <94C20F55-D3B8-4349-B26F-9EA8AAEBF639@caramail.com>
2021-01-21 12:33 ` Hector Martin 'marcan'
2021-01-21 10:52 ` Arnd Bergmann
2021-01-21 11:01 ` Mohamed Mediouni
2021-01-21 11:36 ` Arnd Bergmann
2021-01-20 13:27 ` [RFC PATCH 3/7] arm64: mm: use nGnRnE instead of nGnRE on Apple processors Mohamed Mediouni
2021-01-20 16:47 ` Alexander Graf
2021-01-20 18:06 ` Mohamed Mediouni
2021-01-20 18:10 ` Alexander Graf
2021-01-21 11:27 ` Will Deacon
2021-01-21 11:38 ` Arnd Bergmann
2021-01-21 11:44 ` Marc Zyngier
2021-01-21 12:47 ` Will Deacon
2021-01-21 15:12 ` Mohamed Mediouni
2021-01-21 16:25 ` Marc Zyngier
2021-01-21 17:55 ` Will Deacon
2021-01-21 18:15 ` Marc Zyngier
2021-01-21 18:22 ` Mohamed Mediouni
2021-01-21 18:22 ` Will Deacon
2021-01-20 13:27 ` [RFC PATCH 4/7] irqchip/apple-aic: Add support for Apple AIC Mohamed Mediouni
2021-01-20 17:11 ` Alexander Graf
2021-01-20 18:04 ` Mohamed Mediouni
2021-01-20 20:16 ` Andrew Lunn
2021-01-20 21:18 ` Stan Skowronek
2021-01-21 9:48 ` Linus Walleij
2021-01-21 10:37 ` Arnd Bergmann
2021-01-21 15:29 ` Hector Martin 'marcan'
2021-01-21 17:09 ` Rob Herring
2021-01-21 17:45 ` Rob Herring
2021-01-21 16:44 ` Rob Herring
2021-01-21 16:53 ` Hector Martin 'marcan'
2021-01-20 13:27 ` [RFC PATCH 5/7] arm64/Kconfig: Add Apple Silicon SoC platform Mohamed Mediouni
2021-01-20 13:27 ` [RFC PATCH 6/7] arm64: kernel: Apple CPU start driver Mohamed Mediouni
2021-01-21 11:14 ` Arnd Bergmann
2021-01-20 13:27 ` [RFC PATCH 7/7] irqchip/apple-aic: add SMP support to the Apple AIC driver Mohamed Mediouni
2021-01-21 12:44 ` Arnd Bergmann
2021-01-21 12:50 ` Mohamed Mediouni
2021-01-21 13:00 ` Arnd Bergmann
2021-01-21 13:01 ` Hector Martin 'marcan'
2021-01-21 13:22 ` Marc Zyngier
2021-01-21 13:32 ` Mark Rutland
2021-01-21 14:05 ` Marc Zyngier
2021-01-21 13:34 ` Mohamed Mediouni
2021-01-21 14:10 ` Marc Zyngier
2021-01-21 15:09 ` Arnd Bergmann
2021-01-21 15:18 ` Mohamed Mediouni
2021-01-21 16:40 ` Rob Herring
2021-01-21 16:43 ` Mohamed Mediouni
2021-01-21 17:37 ` Rob Herring
2021-01-21 18:08 ` Mohamed Mediouni
2021-01-21 18:57 ` Rob Herring
2021-02-02 19:15 ` Linus Walleij
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