Commit ebba638a authored by Kees Cook's avatar Kees Cook Committed by H. Peter Anvin
Browse files

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: default avatarKees Cook <>
LKML-Reference: <>
Acked-by: default avatarPekka Enberg <>
Acked-by: default avatarAlan Cox <>
Signed-off-by: default avatarH. Peter Anvin <>
parent ae84739c
......@@ -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
/* Execute Disable bit supported? */
......@@ -609,6 +613,8 @@ ignore_int:
#include "verify_cpu.S"
.align 4
......@@ -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
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