From: Eric DeVolder <eric.devolder@xxxxxxxxxx>
commit fed8d8773b8ea68ad99d9eee8c8343bef9da2c2c upstream.
The logic in acpi_is_processor_usable() requires the online capable
bit be set for hotpluggable CPUs. The online capable bit has been
introduced in ACPI 6.3.
However, for ACPI revisions < 6.3 which do not support that bit, CPUs
should be reported as usable, not the other way around.
Reverse the check.
[ bp: Rewrite commit message. ]
Fixes: e2869bd7af60 ("x86/acpi/boot: Do not register processors that cannot be onlined for x2APIC")
Suggested-by: Miguel Luis <miguel.luis@xxxxxxxxxx>
Suggested-by: Boris Ostrovsky <boris.ovstrosky@xxxxxxxxxx>
Signed-off-by: Eric DeVolder <eric.devolder@xxxxxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Tested-by: David R <david@xxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230327191026.3454-2-eric.devolder@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/acpi/boot.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -193,7 +193,8 @@ static bool __init acpi_is_processor_usa
if (lapic_flags & ACPI_MADT_ENABLED)
return true;
- if (acpi_support_online_capable && (lapic_flags & ACPI_MADT_ONLINE_CAPABLE))
+ if (!acpi_support_online_capable ||
+ (lapic_flags & ACPI_MADT_ONLINE_CAPABLE))
return true;
return false;
