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Message-ID: <20250102150201.21639-4-frederic@kernel.org>
Date: Thu, 2 Jan 2025 16:01:57 +0100
From: Frederic Weisbecker <frederic@...nel.org>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Frederic Weisbecker <frederic@...nel.org>,
Jacob Pan <jacob.jun.pan@...ux.intel.com>,
Peter Zijlstra <peterz@...radead.org>,
"Rafael J . Wysocki" <rafael@...nel.org>,
Daniel Lezcano <daniel.lezcano@...aro.org>,
linux-pm@...r.kernel.org,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
Borislav Petkov <bp@...en8.de>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Russell King <linux@...linux.org.uk>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>,
Michael Ellerman <mpe@...erman.id.au>,
Nicholas Piggin <npiggin@...il.com>,
Christophe Leroy <christophe.leroy@...roup.eu>,
Madhavan Srinivasan <maddy@...ux.ibm.com>,
Paul Walmsley <paul.walmsley@...ive.com>,
Palmer Dabbelt <palmer@...belt.com>,
Albert Ou <aou@...s.berkeley.edu>,
Len Brown <lenb@...nel.org>,
Arnd Bergmann <arnd@...db.de>,
linux-arch@...r.kernel.org
Subject: [PATCH 3/6] x86/cpuidle: Move buggy mwait implementations away from CPUIDLE_FLAG_MWAIT
Buggy MWAIT implementations can't carry the CPUIDLE_FLAG_MWAIT flag
because they require IPIs to wake up. Therefore they shouldn't be
called with TIF_NR_POLLING.
Reported-by: Rafael J. Wysocki <rafael@...nel.org>
Signed-off-by: Frederic Weisbecker <frederic@...nel.org>
---
arch/arm/include/asm/cpuidle.h | 2 ++
arch/arm64/include/asm/cpuidle.h | 3 +++
arch/powerpc/include/asm/cpuidle.h | 4 ++++
arch/riscv/include/asm/cpuidle.h | 2 ++
arch/x86/include/asm/cpuidle.h | 12 ++++++++++++
drivers/acpi/processor_idle.c | 4 +++-
drivers/idle/intel_idle.c | 9 +++++++--
include/asm-generic/Kbuild | 1 +
include/asm-generic/cpuidle.h | 10 ++++++++++
9 files changed, 44 insertions(+), 3 deletions(-)
create mode 100644 arch/x86/include/asm/cpuidle.h
create mode 100644 include/asm-generic/cpuidle.h
diff --git a/arch/arm/include/asm/cpuidle.h b/arch/arm/include/asm/cpuidle.h
index 397be5ed30e7..0ea1d2ec837d 100644
--- a/arch/arm/include/asm/cpuidle.h
+++ b/arch/arm/include/asm/cpuidle.h
@@ -55,4 +55,6 @@ struct arm_cpuidle_irq_context { };
#define arm_cpuidle_save_irq_context(c) (void)c
#define arm_cpuidle_restore_irq_context(c) (void)c
+#include <asm-generic/cpuidle.h>
+
#endif
diff --git a/arch/arm64/include/asm/cpuidle.h b/arch/arm64/include/asm/cpuidle.h
index 2047713e097d..ef49124135a7 100644
--- a/arch/arm64/include/asm/cpuidle.h
+++ b/arch/arm64/include/asm/cpuidle.h
@@ -38,4 +38,7 @@ struct arm_cpuidle_irq_context { };
#define arm_cpuidle_save_irq_context(c) (void)c
#define arm_cpuidle_restore_irq_context(c) (void)c
#endif
+
+#include <asm-generic/cpuidle.h>
+
#endif
diff --git a/arch/powerpc/include/asm/cpuidle.h b/arch/powerpc/include/asm/cpuidle.h
index 0cce5dc7fb1c..788706bc04ec 100644
--- a/arch/powerpc/include/asm/cpuidle.h
+++ b/arch/powerpc/include/asm/cpuidle.h
@@ -102,4 +102,8 @@ static inline void report_invalid_psscr_val(u64 psscr_val, int err)
#endif
+#ifndef __ASSEMBLY__
+#include <asm-generic/cpuidle.h>
+#endif
+
#endif
diff --git a/arch/riscv/include/asm/cpuidle.h b/arch/riscv/include/asm/cpuidle.h
index 71fdc607d4bc..1f1b24901d86 100644
--- a/arch/riscv/include/asm/cpuidle.h
+++ b/arch/riscv/include/asm/cpuidle.h
@@ -21,4 +21,6 @@ static inline void cpu_do_idle(void)
wait_for_interrupt();
}
+#include <asm-generic/cpuidle.h>
+
#endif
diff --git a/arch/x86/include/asm/cpuidle.h b/arch/x86/include/asm/cpuidle.h
new file mode 100644
index 000000000000..a59db1a3314a
--- /dev/null
+++ b/arch/x86/include/asm/cpuidle.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_CPUIDLE_H
+#define _ASM_X86_CPUIDLE_H
+
+#include <asm/cpufeature.h>
+
+static inline bool arch_cpuidle_mwait_needs_ipi(void)
+{
+ return boot_cpu_has_bug(X86_BUG_MONITOR);
+}
+
+#endif /* _ASM_X86_CPUIDLE_H */
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 66cb5536d91e..0f29dd92b346 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -23,6 +23,7 @@
#include <linux/perf_event.h>
#include <acpi/processor.h>
#include <linux/context_tracking.h>
+#include <asm/cpuidle.h>
/*
* Include the apic definitions for x86 to have the APIC timer related defines
@@ -806,7 +807,8 @@ static int acpi_processor_setup_cstates(struct acpi_processor *pr)
if (cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2)
drv->safe_state_index = count;
- if (cx->entry_method == ACPI_CSTATE_FFH)
+ if (cx->entry_method == ACPI_CSTATE_FFH &&
+ !arch_cpuidle_mwait_needs_ipi())
state->flags |= CPUIDLE_FLAG_MWAIT;
/*
diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index d52723fbeb04..b2f494effd4a 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -56,6 +56,7 @@
#include <asm/mwait.h>
#include <asm/spec-ctrl.h>
#include <asm/fpu/api.h>
+#include <asm/cpuidle.h>
#define INTEL_IDLE_VERSION "0.5.1"
@@ -1787,7 +1788,10 @@ static void __init intel_idle_init_cstates_acpi(struct cpuidle_driver *drv)
if (cx->type > ACPI_STATE_C1)
state->target_residency *= 3;
- state->flags = MWAIT2flg(cx->address) | CPUIDLE_FLAG_MWAIT;
+ state->flags = MWAIT2flg(cx->address);
+
+ if (!arch_cpuidle_mwait_needs_ipi())
+ state->flags |= CPUIDLE_FLAG_MWAIT;
if (cx->type > ACPI_STATE_C2)
state->flags |= CPUIDLE_FLAG_TLB_FLUSHED;
@@ -2073,7 +2077,8 @@ static bool __init intel_idle_verify_cstate(unsigned int mwait_hint)
static void state_update_enter_method(struct cpuidle_state *state, int cstate)
{
- state->flags |= CPUIDLE_FLAG_MWAIT;
+ if (!arch_cpuidle_mwait_needs_ipi())
+ state->flags |= CPUIDLE_FLAG_MWAIT;
if (state->flags & CPUIDLE_FLAG_INIT_XSTATE) {
/*
diff --git a/include/asm-generic/Kbuild b/include/asm-generic/Kbuild
index 1b43c3a77012..7754da499d16 100644
--- a/include/asm-generic/Kbuild
+++ b/include/asm-generic/Kbuild
@@ -13,6 +13,7 @@ mandatory-y += cacheflush.h
mandatory-y += cfi.h
mandatory-y += checksum.h
mandatory-y += compat.h
+mandatory-y += cpuidle.h
mandatory-y += current.h
mandatory-y += delay.h
mandatory-y += device.h
diff --git a/include/asm-generic/cpuidle.h b/include/asm-generic/cpuidle.h
new file mode 100644
index 000000000000..748a2022ed2a
--- /dev/null
+++ b/include/asm-generic/cpuidle.h
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_CPUIDLE_H
+#define __ASM_CPUIDLE_H
+
+static inline bool arch_cpuidle_mwait_needs_ipi(void)
+{
+ return true;
+}
+
+#endif /* __ASM_CPUIDLE_H */
--
2.46.0
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