From patchwork Wed Dec 13 12:50:38 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Russell King (Oracle)" X-Patchwork-Id: 13490874 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="C8V6ZPDm" Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 856F9172E; Wed, 13 Dec 2023 04:50:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Date:Sender:Message-Id:Content-Type: Content-Transfer-Encoding:MIME-Version:Subject:Cc:To:From:References: In-Reply-To:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=zH347rXIT/Wy1fT2AxJrWucdhRljJuHMrMKFDlPOdGs=; b=C8V6ZPDmidjU0rPM3MNO+Oz7/r 9Q4u3gedUI33lJ3NyGNwKUy257pNGfSyYof4TiYnY84kRmEo7Mjfg8LvEbcLtLDFgYbhhYPYk2DM6 qL91mkIsdsCL8QpgAEvD98lEcW9ZWUCCtXbaZRScR4ytVUzn0OSU3bWGhXZ0f+Zow2X/C+jtBjBCJ 8k7jFCMRILZ83BDKElnsNyxKh8EE1JHqMJBWe4q2OZIRUlrlhx2Gv/XPkllFPQS3+FndJm9Ov670Y khCRzwlW2Se1hrI6UNoeQT7K33f2KTHrEpmLBpfwq30WM335VyRik2rw9Vls1PanX7hwhyv2vD+Cu BIEJ2DIw==; Received: from e0022681537dd.dyn.armlinux.org.uk ([fd8f:7570:feb6:1:222:68ff:fe15:37dd]:51442 helo=rmk-PC.armlinux.org.uk) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1rDOhA-0008HE-1e; Wed, 13 Dec 2023 12:50:36 +0000 Received: from rmk by rmk-PC.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1rDOhC-00DvlI-Pp; Wed, 13 Dec 2023 12:50:38 +0000 In-Reply-To: References: From: Russell King (Oracle) To: linux-pm@vger.kernel.org, loongarch@lists.linux.dev, linux-acpi@vger.kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-riscv@lists.infradead.org, kvmarm@lists.linux.dev, x86@kernel.org, acpica-devel@lists.linuxfoundation.org, linux-csky@vger.kernel.org, linux-doc@vger.kernel.org, linux-ia64@vger.kernel.org, linux-parisc@vger.kernel.org Cc: Salil Mehta , Jean-Philippe Brucker , jianyong.wu@arm.com, justin.he@arm.com, James Morse Subject: [PATCH RFC v3 17/21] ACPI: add support to register CPUs based on the _STA enabled bit Precedence: bulk X-Mailing-List: linux-parisc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline Message-Id: Sender: Russell King Date: Wed, 13 Dec 2023 12:50:38 +0000 From: James Morse acpi_processor_get_info() registers all present CPUs. Registering a CPU is what creates the sysfs entries and triggers the udev notifications. arm64 virtual machines that support 'virtual cpu hotplug' use the enabled bit to indicate whether the CPU can be brought online, as the existing ACPI tables require all hardware to be described and present. If firmware describes a CPU as present, but disabled, skip the registration. Such CPUs are present, but can't be brought online for whatever reason. (e.g. firmware/hypervisor policy). Once firmware sets the enabled bit, the CPU can be registered and brought online by user-space. Online CPUs, or CPUs that are missing an _STA method must always be registered. Signed-off-by: James Morse Reviewed-by: Gavin Shan Reviewed-by: Jonathan Cameron Tested-by: Miguel Luis Tested-by: Vishnu Pajjuri Tested-by: Jianyong Wu Signed-off-by: Russell King (Oracle) --- drivers/acpi/acpi_processor.c | 31 ++++++++++++++++++++++++++++++- 1 file changed, 30 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c index b7a94c1348b0..5dabb426481f 100644 --- a/drivers/acpi/acpi_processor.c +++ b/drivers/acpi/acpi_processor.c @@ -228,6 +228,32 @@ static int acpi_processor_make_present(struct acpi_processor *pr) return ret; } +static int acpi_processor_make_enabled(struct acpi_processor *pr) +{ + unsigned long long sta; + acpi_status status; + bool present, enabled; + + if (!acpi_has_method(pr->handle, "_STA")) + return arch_register_cpu(pr->id); + + status = acpi_evaluate_integer(pr->handle, "_STA", NULL, &sta); + if (ACPI_FAILURE(status)) + return -ENODEV; + + present = sta & ACPI_STA_DEVICE_PRESENT; + enabled = sta & ACPI_STA_DEVICE_ENABLED; + + if (cpu_online(pr->id) && (!present || !enabled)) { + pr_err_once(FW_BUG "CPU %u is online, but described as not present or disabled!\n", pr->id); + add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK); + } else if (!present || !enabled) { + return -ENODEV; + } + + return arch_register_cpu(pr->id); +} + static int acpi_processor_get_info(struct acpi_device *device) { union acpi_object object = { 0 }; @@ -318,7 +344,7 @@ static int acpi_processor_get_info(struct acpi_device *device) */ if (!invalid_logical_cpuid(pr->id) && cpu_present(pr->id) && !get_cpu_device(pr->id)) { - int ret = arch_register_cpu(pr->id); + int ret = acpi_processor_make_enabled(pr); if (ret) return ret; @@ -526,6 +552,9 @@ static void acpi_processor_post_eject(struct acpi_device *device) acpi_processor_make_not_present(device); return; } + + if (cpu_present(pr->id) && !(sta & ACPI_STA_DEVICE_ENABLED)) + arch_unregister_cpu(pr->id); } #ifdef CONFIG_ARCH_MIGHT_HAVE_ACPI_PDC