From ebba638ae723d8a8fc2f7abce5ec18b688b791d7 Mon Sep 17 00:00:00 2001 From: Kees Cook <kees.cook@canonical.com> Date: Wed, 10 Nov 2010 10:35:53 -0800 Subject: [PATCH] x86, cpu: Call verify_cpu during 32bit CPU startup The XD_DISABLE-clearing side-effect needs to happen for both 32bit and 64bit, but the 32bit init routines were not calling verify_cpu() yet. This adds that call to gain the side-effect. The longmode/SSE tests being performed in verify_cpu() need to happen very early for 64bit but not for 32bit. Instead of including it in two places for 32bit, we can just include it once in arch/x86/kernel/head_32.S. Signed-off-by: Kees Cook <kees.cook@canonical.com> LKML-Reference: <1289414154-7829-4-git-send-email-kees.cook@canonical.com> Acked-by: Pekka Enberg <penberg@kernel.org> Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> --- arch/x86/kernel/head_32.S | 6 ++++++ arch/x86/kernel/verify_cpu.S | 1 + 2 files changed, 7 insertions(+) diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S index bcece91dd311..fdaea523ac8f 100644 --- a/arch/x86/kernel/head_32.S +++ b/arch/x86/kernel/head_32.S @@ -314,6 +314,10 @@ ENTRY(startup_32_smp) subl $0x80000001, %eax cmpl $(0x8000ffff-0x80000001), %eax ja 6f + + /* Clear bogus XD_DISABLE bits */ + call verify_cpu + mov $0x80000001, %eax cpuid /* Execute Disable bit supported? */ @@ -609,6 +613,8 @@ ignore_int: #endif iret +#include "verify_cpu.S" + __REFDATA .align 4 ENTRY(initial_code) diff --git a/arch/x86/kernel/verify_cpu.S b/arch/x86/kernel/verify_cpu.S index ccb4136da0aa..5644b4b7ed28 100644 --- a/arch/x86/kernel/verify_cpu.S +++ b/arch/x86/kernel/verify_cpu.S @@ -19,6 +19,7 @@ * * arch/x86_64/boot/compressed/head_64.S: Boot cpu verification * arch/x86_64/kernel/trampoline_64.S: secondary processor verfication + * arch/x86_64/kernel/head_32.S: processor startup * * verify_cpu, returns the status of longmode and SSE in register %eax. * 0: Success 1: Failure -- GitLab