x86/cpu: Validate CPUID leaf 0x2 EDX output
authorAhmed S. Darwish <darwi@linutronix.de>
Tue, 4 Mar 2025 08:51:13 +0000 (09:51 +0100)
committerIngo Molnar <mingo@kernel.org>
Tue, 4 Mar 2025 08:59:14 +0000 (09:59 +0100)
commit1881148215c67151b146450fb89ec22fd92337a7
tree393dab7156c462c71907ba0c4fa363f1da674227
parent8177c6bedb7013cf736137da586cf783922309dd
x86/cpu: Validate CPUID leaf 0x2 EDX output

CPUID leaf 0x2 emits one-byte descriptors in its four output registers
EAX, EBX, ECX, and EDX.  For these descriptors to be valid, the most
significant bit (MSB) of each register must be clear.

Leaf 0x2 parsing at intel.c only validated the MSBs of EAX, EBX, and
ECX, but left EDX unchecked.

Validate EDX's most-significant bit as well.

Fixes: e0ba94f14f74 ("x86/tlb_info: get last level TLB entry number of CPU")
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: stable@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250304085152.51092-3-darwi@linutronix.de
arch/x86/kernel/cpu/intel.c