[PATCH 3/6] x86/cpuidle: Move buggy mwait implementations away from CPUIDLE_FLAG_MWAIT

[Frederic Weisbecker <frederic@kernel.org>]

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@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.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