This is a note to let you know that I've just added the patch titled
cpuidle, ACPI: Evaluate LPI arch_flags for broadcast timer
to the 6.5-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
cpuidle-acpi-evaluate-lpi-arch_flags-for-broadcast-t.patch
and it can be found in the queue-6.5 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 1715a813faf0596472dec3f01f95625195d76540
Author: Oza Pawandeep <quic_poza@xxxxxxxxxxx>
Date: Tue Oct 3 10:33:33 2023 -0700
cpuidle, ACPI: Evaluate LPI arch_flags for broadcast timer
[ Upstream commit 4785aa8028536c2be656d22c74ec1995b97056f3 ]
Arm® Functional Fixed Hardware Specification defines LPI states,
which provide an architectural context loss flags field that can
be used to describe the context that might be lost when an LPI
state is entered.
- Core context Lost
- General purpose registers.
- Floating point and SIMD registers.
- System registers, include the System register based
- generic timer for the core.
- Debug register in the core power domain.
- PMU registers in the core power domain.
- Trace register in the core power domain.
- Trace context loss
- GICR
- GICD
Qualcomm's custom CPUs preserves the architectural state,
including keeping the power domain for local timers active.
when core is power gated, the local timers are sufficient to
wake the core up without needing broadcast timer.
The patch fixes the evaluation of cpuidle arch_flags, and moves only to
broadcast timer if core context lost is defined in ACPI LPI.
Fixes: a36a7fecfe60 ("ACPI / processor_idle: Add support for Low Power Idle(LPI) states")
Reviewed-by: Sudeep Holla <sudeep.holla@xxxxxxx>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Oza Pawandeep <quic_poza@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20231003173333.2865323-1-quic_poza@xxxxxxxxxxx
Signed-off-by: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
index 4d537d56eb847..6792a1f83f2ad 100644
--- a/arch/arm64/include/asm/acpi.h
+++ b/arch/arm64/include/asm/acpi.h
@@ -9,6 +9,7 @@
#ifndef _ASM_ACPI_H
#define _ASM_ACPI_H
+#include <linux/cpuidle.h>
#include <linux/efi.h>
#include <linux/memblock.h>
#include <linux/psci.h>
@@ -44,6 +45,24 @@
#define ACPI_MADT_GICC_TRBE (offsetof(struct acpi_madt_generic_interrupt, \
trbe_interrupt) + sizeof(u16))
+/*
+ * Arm® Functional Fixed Hardware Specification Version 1.2.
+ * Table 2: Arm Architecture context loss flags
+ */
+#define CPUIDLE_CORE_CTXT BIT(0) /* Core context Lost */
+
+static inline unsigned int arch_get_idle_state_flags(u32 arch_flags)
+{
+ if (arch_flags & CPUIDLE_CORE_CTXT)
+ return CPUIDLE_FLAG_TIMER_STOP;
+
+ return 0;
+}
+#define arch_get_idle_state_flags arch_get_idle_state_flags
+
+#define CPUIDLE_TRACE_CTXT BIT(1) /* Trace context loss */
+#define CPUIDLE_GICR_CTXT BIT(2) /* GICR */
+#define CPUIDLE_GICD_CTXT BIT(3) /* GICD */
/* Basic configuration for ACPI */
#ifdef CONFIG_ACPI
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index dc615ef6550a1..3a34a8c425fe4 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -1217,8 +1217,7 @@ static int acpi_processor_setup_lpi_states(struct acpi_processor *pr)
strscpy(state->desc, lpi->desc, CPUIDLE_DESC_LEN);
state->exit_latency = lpi->wake_latency;
state->target_residency = lpi->min_residency;
- if (lpi->arch_flags)
- state->flags |= CPUIDLE_FLAG_TIMER_STOP;
+ state->flags |= arch_get_idle_state_flags(lpi->arch_flags);
if (i != 0 && lpi->entry_method == ACPI_CSTATE_FFH)
state->flags |= CPUIDLE_FLAG_RCU_IDLE;
state->enter = acpi_idle_lpi_enter;
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 641dc48439873..42c22a6ff48d0 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -1476,6 +1476,15 @@ static inline int lpit_read_residency_count_address(u64 *address)
}
#endif
+#ifdef CONFIG_ACPI_PROCESSOR_IDLE
+#ifndef arch_get_idle_state_flags
+static inline unsigned int arch_get_idle_state_flags(u32 arch_flags)
+{
+ return 0;
+}
+#endif
+#endif /* CONFIG_ACPI_PROCESSOR_IDLE */
+
#ifdef CONFIG_ACPI_PPTT
int acpi_pptt_cpu_is_thread(unsigned int cpu);
int find_acpi_cpu_topology(unsigned int cpu, int level);
