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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 <kees.cook@canonical.com>
LKML-Reference: <1289414154-7829-4-git-send-email-kees.cook@canonical.com>
Acked-by: default avatarPekka Enberg <penberg@kernel.org>
Acked-by: default avatarAlan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent ae84739c

arch/x86/kernel/head_32.S

+6 −0
Original line number Original line Diff line number Diff line
@@ -314,6 +314,10 @@ ENTRY(startup_32_smp) 
	subl $0x80000001, %eax

	subl $0x80000001, %eax

	cmpl $(0x8000ffff-0x80000001), %eax

	cmpl $(0x8000ffff-0x80000001), %eax

	ja 6f

	ja 6f



	/* Clear bogus XD_DISABLE bits */

	call verify_cpu



	mov $0x80000001, %eax

	mov $0x80000001, %eax

	cpuid

	cpuid

	/* Execute Disable bit supported? */

	/* Execute Disable bit supported? */
@@ -609,6 +613,8 @@ ignore_int: 
#endif

#endif

	iret

	iret





#include "verify_cpu.S"



	__REFDATA

	__REFDATA

.align 4

.align 4

ENTRY(initial_code)

ENTRY(initial_code)

arch/x86/kernel/verify_cpu.S

+1 −0
Original line number Original line Diff line number Diff line
@@ -19,6 +19,7 @@ 
 *

 *

 *	arch/x86_64/boot/compressed/head_64.S: Boot cpu verification

 *	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/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.

 *	verify_cpu, returns the status of longmode and SSE in register %eax.

 *		0: Success    1: Failure

 *		0: Success    1: Failure