x86, cpu: Rename verify_cpu_64.S to verify_cpu.S

The code is 32bit already, and can be used in 32bit routines.

Signed-off-by: Kees Cook <kees.cook@canonical.com>
LKML-Reference: <1289414154-7829-2-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>

1 files changed, 106 insertions, 0 deletions

diff --git a/arch/x86/kernel/verify_cpu.S b/arch/x86/kernel/verify_cpu.S
new file mode 100644
index 000000000000..56a8c2a867d9
--- /dev/null
+++ b/arch/x86/kernel/verify_cpu.S
@@ -0,0 +1,106 @@
+/*
+ *
+ *	verify_cpu.S - Code for cpu long mode and SSE verification. This
+ *	code has been borrowed from boot/setup.S and was introduced by
+ * 	Andi Kleen.
+ *
+ *	Copyright (c) 2007  Andi Kleen (ak@suse.de)
+ *	Copyright (c) 2007  Eric Biederman (ebiederm@xmission.com)
+ *	Copyright (c) 2007  Vivek Goyal (vgoyal@in.ibm.com)
+ *
+ * 	This source code is licensed under the GNU General Public License,
+ * 	Version 2.  See the file COPYING for more details.
+ *
+ *	This is a common code for verification whether CPU supports
+ * 	long mode and SSE or not. It is not called directly instead this
+ *	file is included at various places and compiled in that context.
+ * 	Following are the current usage.
+ *
+ * 	This file is included by both 16bit and 32bit code.
+ *
+ *	arch/x86_64/boot/setup.S : Boot cpu verification (16bit)
+ *	arch/x86_64/boot/compressed/head.S: Boot cpu verification (32bit)
+ *	arch/x86_64/kernel/trampoline.S: secondary processor verfication (16bit)
+ *	arch/x86_64/kernel/acpi/wakeup.S:Verfication at resume (16bit)
+ *
+ *	verify_cpu, returns the status of cpu check in register %eax.
+ *		0: Success    1: Failure
+ *
+ * 	The caller needs to check for the error code and take the action
+ * 	appropriately. Either display a message or halt.
+ */
+
+#include <asm/cpufeature.h>
+#include <asm/msr-index.h>
+
+verify_cpu:
+	pushfl				# Save caller passed flags
+	pushl	$0			# Kill any dangerous flags
+	popfl
+
+	pushfl				# standard way to check for cpuid
+	popl	%eax
+	movl	%eax,%ebx
+	xorl	$0x200000,%eax
+	pushl	%eax
+	popfl
+	pushfl
+	popl	%eax
+	cmpl	%eax,%ebx
+	jz	verify_cpu_no_longmode	# cpu has no cpuid
+
+	movl	$0x0,%eax		# See if cpuid 1 is implemented
+	cpuid
+	cmpl	$0x1,%eax
+	jb	verify_cpu_no_longmode	# no cpuid 1
+
+	xor	%di,%di
+	cmpl	$0x68747541,%ebx	# AuthenticAMD
+	jnz	verify_cpu_noamd
+	cmpl	$0x69746e65,%edx
+	jnz	verify_cpu_noamd
+	cmpl	$0x444d4163,%ecx
+	jnz	verify_cpu_noamd
+	mov	$1,%di			# cpu is from AMD
+
+verify_cpu_noamd:
+	movl    $0x1,%eax		# Does the cpu have what it takes
+	cpuid
+	andl	$REQUIRED_MASK0,%edx
+	xorl	$REQUIRED_MASK0,%edx
+	jnz	verify_cpu_no_longmode
+
+	movl    $0x80000000,%eax	# See if extended cpuid is implemented
+	cpuid
+	cmpl    $0x80000001,%eax
+	jb      verify_cpu_no_longmode	# no extended cpuid
+
+	movl    $0x80000001,%eax	# Does the cpu have what it takes
+	cpuid
+	andl    $REQUIRED_MASK1,%edx
+	xorl    $REQUIRED_MASK1,%edx
+	jnz     verify_cpu_no_longmode
+
+verify_cpu_sse_test:
+	movl	$1,%eax
+	cpuid
+	andl	$SSE_MASK,%edx
+	cmpl	$SSE_MASK,%edx
+	je	verify_cpu_sse_ok
+	test	%di,%di
+	jz	verify_cpu_no_longmode	# only try to force SSE on AMD
+	movl	$MSR_K7_HWCR,%ecx
+	rdmsr
+	btr	$15,%eax		# enable SSE
+	wrmsr
+	xor	%di,%di			# don't loop
+	jmp	verify_cpu_sse_test	# try again
+
+verify_cpu_no_longmode:
+	popfl				# Restore caller passed flags
+	movl $1,%eax
+	ret
+verify_cpu_sse_ok:
+	popfl				# Restore caller passed flags
+	xorl %eax, %eax
+	ret