diff options
Diffstat (limited to 'arch/x86/kernel/verify_cpu.S')
| -rw-r--r-- | arch/x86/kernel/verify_cpu.S | 106 |
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 |