diff mbox series

[tip:,x86/urgent] x86/ACPI/boot: Use FADT version to check support for online capable

Message ID 168016878085.404.6003734700616193238.tip-bot2@tip-bot2
State New
Headers
Series [tip:,x86/urgent] x86/ACPI/boot: Use FADT version to check support for online capable |

Commit Message

tip-bot2 for Thomas Gleixner March 30, 2023, 9:33 a.m. UTC 
  The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     a74fabfbd1b7013045afc8cc541e6cab3360ccb5
Gitweb:        https://git.kernel.org/tip/a74fabfbd1b7013045afc8cc541e6cab3360ccb5
Author:        Mario Limonciello <mario.limonciello@amd.com>
AuthorDate:    Wed, 29 Mar 2023 12:45:35 -05:00
Committer:     Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Thu, 30 Mar 2023 10:50:30 +02:00

x86/ACPI/boot: Use FADT version to check support for online capable

ACPI 6.3 introduced the online capable bit, and also introduced MADT
version 5.

Latter was used to distinguish whether the offset storing online capable
could be used. However ACPI 6.2b has MADT version "45" which is for
an errata version of the ACPI 6.2 spec.  This means that the Linux code
for detecting availability of MADT will mistakenly flag ACPI 6.2b as
supporting online capable which is inaccurate as it's an ACPI 6.3 feature.

Instead use the FADT major and minor revision fields to distinguish this.

  [ bp: Massage. ]

Fixes: aa06e20f1be6 ("x86/ACPI: Don't add CPUs that are not online capable")
Reported-by: Eric DeVolder <eric.devolder@oracle.com>
Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/943d2445-84df-d939-f578-5d8240d342cc@unsolicited.net
---
 arch/x86/kernel/acpi/boot.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 1c38174..7292184 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -146,7 +146,11 @@  static int __init acpi_parse_madt(struct acpi_table_header *table)
 
 		pr_debug("Local APIC address 0x%08x\n", madt->address);
 	}
-	if (madt->header.revision >= 5)
+
+	/* ACPI 6.3 and newer support the online capable bit. */
+	if (acpi_gbl_FADT.header.revision > 6 ||
+	    (acpi_gbl_FADT.header.revision == 6 &&
+	     acpi_gbl_FADT.minor_revision >= 3))
 		acpi_support_online_capable = true;
 
 	default_acpi_madt_oem_check(madt->header.oem_id,