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authorKees Cook <kees.cook@canonical.com>2010-11-10 10:35:51 -0800
committerH. Peter Anvin <hpa@linux.intel.com>2010-11-10 15:42:42 -0800
commitc5cbac69422a9bffe7c7fd9a115130e272b547f5 (patch)
tree57b3b12e6569bd79a66e981be7fb47e8e7cea5af /arch/x86/kernel/verify_cpu.S
parentc8ddb2713c624f432fa5fe3c7ecffcdda46ea0d4 (diff)
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>
Diffstat (limited to 'arch/x86/kernel/verify_cpu.S')
-rw-r--r--arch/x86/kernel/verify_cpu.S106
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