linux-kernel - [PATCH AUTOSEL 5.16 190/217] ACPI: CPPC: Check present CPUs for determining

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Message-Id: <20220118021940.1942199-190-sashal@kernel.org>
Date:   Mon, 17 Jan 2022 21:19:13 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Mario Limonciello <mario.limonciello@....com>,
        Jinzhou Su <Jinzhou.Su@....com>, Huang Rui <ray.huang@....com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Sasha Levin <sashal@...nel.org>, rafael@...nel.org,
        linux-acpi@...r.kernel.org
Subject: [PATCH AUTOSEL 5.16 190/217] ACPI: CPPC: Check present CPUs for determining _CPC is valid

From: Mario Limonciello <mario.limonciello@....com>

[ Upstream commit 2aeca6bd02776d7f56a49a32be0dd184f204d888 ]

As this is a static check, it should be based upon what is currently
present on the system. This makes probeing more deterministic.

While local APIC flags field (lapic_flags) of cpu core in MADT table is
0, then the cpu core won't be enabled. In this case, _CPC won't be found
in this core, and return back to _CPC invalid with walking through
possible cpus (include disable cpus). This is not expected, so switch to
check present CPUs instead.

Reported-by: Jinzhou Su <Jinzhou.Su@....com>
Signed-off-by: Mario Limonciello <mario.limonciello@....com>
Signed-off-by: Huang Rui <ray.huang@....com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/acpi/cppc_acpi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index b62c87b8ce4a9..12a156d8283e6 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -411,7 +411,7 @@ bool acpi_cpc_valid(void)
 	struct cpc_desc *cpc_ptr;
 	int cpu;
 
-	for_each_possible_cpu(cpu) {
+	for_each_present_cpu(cpu) {
 		cpc_ptr = per_cpu(cpc_desc_ptr, cpu);
 		if (!cpc_ptr)
 			return false;
-- 
2.34.1