linux-kernel - [PATCH v4 5/9] acpi: Clear C_C2C3_FFH and C_C1_FFH in arch_acpi_set_proc_cap

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Message-ID: <20230710140337.1434060-6-michal.wilczynski@intel.com>
Date:   Mon, 10 Jul 2023 17:03:33 +0300
From:   Michal Wilczynski <michal.wilczynski@...el.com>
To:     linux-acpi@...r.kernel.org
Cc:     rafael@...nel.org, andriy.shevchenko@...el.com,
        artem.bityutskiy@...ux.intel.com, mingo@...hat.com, bp@...en8.de,
        dave.hansen@...ux.intel.com, hpa@...or.com, lenb@...nel.org,
        jgross@...e.com, linux-kernel@...r.kernel.org, x86@...nel.org,
        Michal Wilczynski <michal.wilczynski@...el.com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>
Subject: [PATCH v4 5/9] acpi: Clear C_C2C3_FFH and C_C1_FFH in arch_acpi_set_proc_cap_bits()

Currently arch_acpi_set_proc_cap_bits() clears ACPI_PDC_C_C2C3_FFH bit in
case MWAIT instruction is not supported. It should also clear
ACPI_PDC_C_C1_FFH, as when MWAIT is not supported C1 is accomplished
with HALT instruction. Quote from documentation describing C_C1_FFH:
"If set, OSPM is capable of performing native C State instructions (beyond
halt) for the C1 handler in multi-processor configurations". As without
MWAIT there is no native C-state instructions beyond HALT, this bit
should be toggled off.

Clear ACPI_PDC_C_C1_FFH and ACPI_PDC_C_C2C3_FFH in
arch_acpi_set_proc_cap_bits() in case MWAIT is not supported or overridden.
Remove setting those bits in processor_pdc.c code.

Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Signed-off-by: Michal Wilczynski <michal.wilczynski@...el.com>
---
 arch/x86/include/asm/acpi.h  |  9 +++++----
 drivers/acpi/processor_pdc.c | 14 --------------
 2 files changed, 5 insertions(+), 18 deletions(-)

diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h
index ce5ad6a496e6..d615238bcd78 100644
--- a/arch/x86/include/asm/acpi.h
+++ b/arch/x86/include/asm/acpi.h
@@ -113,11 +113,12 @@ static inline void arch_acpi_set_proc_cap_bits(u32 *cap)
 		*cap |= ACPI_PROC_CAP_T_FFH;
 
 	/*
-	 * If mwait/monitor is unsupported, C2/C3_FFH will be disabled
+	 * If mwait/monitor is unsupported, C_C1_FFH and
+	 * C2/C3_FFH will be disabled.
 	 */
-	if (!cpu_has(c, X86_FEATURE_MWAIT))
-		*cap &= ~(ACPI_PROC_CAP_C_C2C3_FFH);
-
+	if (!cpu_has(c, X86_FEATURE_MWAIT) ||
+	    boot_option_idle_override == IDLE_NOMWAIT)
+		*cap &= ~(ACPI_PROC_CAP_C_C1_FFH | ACPI_PROC_CAP_C_C2C3_FFH);
 }
 
 static inline bool acpi_has_cpu_in_madt(void)
diff --git a/drivers/acpi/processor_pdc.c b/drivers/acpi/processor_pdc.c
index 77d3fe73047c..b4b906b70a0b 100644
--- a/drivers/acpi/processor_pdc.c
+++ b/drivers/acpi/processor_pdc.c
@@ -74,20 +74,6 @@ acpi_processor_eval_pdc(acpi_handle handle, struct acpi_object_list *pdc_in)
 {
 	acpi_status status = AE_OK;
 
-	if (boot_option_idle_override == IDLE_NOMWAIT) {
-		/*
-		 * If mwait is disabled for CPU C-states, the C2C3_FFH access
-		 * mode will be disabled in the parameter of _PDC object.
-		 * Of course C1_FFH access mode will also be disabled.
-		 */
-		union acpi_object *obj;
-		u32 *buffer = NULL;
-
-		obj = pdc_in->pointer;
-		buffer = (u32 *)(obj->buffer.pointer);
-		buffer[2] &= ~(ACPI_PDC_C_C2C3_FFH | ACPI_PDC_C_C1_FFH);
-
-	}
 	status = acpi_evaluate_object(handle, "_PDC", pdc_in, NULL);
 
 	if (ACPI_FAILURE(status))
-- 
2.41.0