140b0b3f8SThomas Gleixner/* SPDX-License-Identifier: GPL-2.0-only */ 2c5cbac69SKees Cook/* 3c5cbac69SKees Cook * 4c5cbac69SKees Cook * verify_cpu.S - Code for cpu long mode and SSE verification. This 5c5cbac69SKees Cook * code has been borrowed from boot/setup.S and was introduced by 6c5cbac69SKees Cook * Andi Kleen. 7c5cbac69SKees Cook * 8c5cbac69SKees Cook * Copyright (c) 2007 Andi Kleen (ak@suse.de) 9c5cbac69SKees Cook * Copyright (c) 2007 Eric Biederman (ebiederm@xmission.com) 10c5cbac69SKees Cook * Copyright (c) 2007 Vivek Goyal (vgoyal@in.ibm.com) 11ae84739cSKees Cook * Copyright (c) 2010 Kees Cook (kees.cook@canonical.com) 12c5cbac69SKees Cook * 13c5cbac69SKees Cook * This is a common code for verification whether CPU supports 14c5cbac69SKees Cook * long mode and SSE or not. It is not called directly instead this 15c5cbac69SKees Cook * file is included at various places and compiled in that context. 16ae84739cSKees Cook * This file is expected to run in 32bit code. Currently: 17c5cbac69SKees Cook * 1879250af2SKees Cook * arch/x86/boot/compressed/head_64.S: Boot cpu verification 190d2eb44fSLucas De Marchi * arch/x86/kernel/trampoline_64.S: secondary processor verification 2079250af2SKees Cook * arch/x86/kernel/head_32.S: processor startup 21c5cbac69SKees Cook * 22ae84739cSKees Cook * verify_cpu, returns the status of longmode and SSE in register %eax. 23c5cbac69SKees Cook * 0: Success 1: Failure 24c5cbac69SKees Cook * 25ae84739cSKees Cook * On Intel, the XD_DISABLE flag will be cleared as a side-effect. 26ae84739cSKees Cook * 27c5cbac69SKees Cook * The caller needs to check for the error code and take the action 28c5cbac69SKees Cook * appropriately. Either display a message or halt. 29c5cbac69SKees Cook */ 30c5cbac69SKees Cook 31cd4d09ecSBorislav Petkov#include <asm/cpufeatures.h> 32c5cbac69SKees Cook#include <asm/msr-index.h> 33c5cbac69SKees Cook 34ef77e688SJiri SlabySYM_FUNC_START_LOCAL(verify_cpu) 3504633df0SBorislav Petkov pushf # Save caller passed flags 3604633df0SBorislav Petkov push $0 # Kill any dangerous flags 3704633df0SBorislav Petkov popf 38c5cbac69SKees Cook 3904633df0SBorislav Petkov#ifndef __x86_64__ 40c5cbac69SKees Cook pushfl # standard way to check for cpuid 41c5cbac69SKees Cook popl %eax 42c5cbac69SKees Cook movl %eax,%ebx 43c5cbac69SKees Cook xorl $0x200000,%eax 44c5cbac69SKees Cook pushl %eax 45c5cbac69SKees Cook popfl 46c5cbac69SKees Cook pushfl 47c5cbac69SKees Cook popl %eax 48c5cbac69SKees Cook cmpl %eax,%ebx 49aa042141SBorislav Petkov jz .Lverify_cpu_no_longmode # cpu has no cpuid 5004633df0SBorislav Petkov#endif 51c5cbac69SKees Cook 52c5cbac69SKees Cook movl $0x0,%eax # See if cpuid 1 is implemented 53c5cbac69SKees Cook cpuid 54c5cbac69SKees Cook cmpl $0x1,%eax 55aa042141SBorislav Petkov jb .Lverify_cpu_no_longmode # no cpuid 1 56c5cbac69SKees Cook 57c5cbac69SKees Cook xor %di,%di 58c5cbac69SKees Cook cmpl $0x68747541,%ebx # AuthenticAMD 59aa042141SBorislav Petkov jnz .Lverify_cpu_noamd 60c5cbac69SKees Cook cmpl $0x69746e65,%edx 61aa042141SBorislav Petkov jnz .Lverify_cpu_noamd 62c5cbac69SKees Cook cmpl $0x444d4163,%ecx 63aa042141SBorislav Petkov jnz .Lverify_cpu_noamd 64c5cbac69SKees Cook mov $1,%di # cpu is from AMD 65aa042141SBorislav Petkov jmp .Lverify_cpu_check 66c5cbac69SKees Cook 67aa042141SBorislav Petkov.Lverify_cpu_noamd: 68ae84739cSKees Cook cmpl $0x756e6547,%ebx # GenuineIntel? 69aa042141SBorislav Petkov jnz .Lverify_cpu_check 70ae84739cSKees Cook cmpl $0x49656e69,%edx 71aa042141SBorislav Petkov jnz .Lverify_cpu_check 72ae84739cSKees Cook cmpl $0x6c65746e,%ecx 73aa042141SBorislav Petkov jnz .Lverify_cpu_check 74ae84739cSKees Cook 75ae84739cSKees Cook # only call IA32_MISC_ENABLE when: 76ae84739cSKees Cook # family > 6 || (family == 6 && model >= 0xd) 77ae84739cSKees Cook movl $0x1, %eax # check CPU family and model 78ae84739cSKees Cook cpuid 79ae84739cSKees Cook movl %eax, %ecx 80ae84739cSKees Cook 81ae84739cSKees Cook andl $0x0ff00f00, %eax # mask family and extended family 82ae84739cSKees Cook shrl $8, %eax 83ae84739cSKees Cook cmpl $6, %eax 84aa042141SBorislav Petkov ja .Lverify_cpu_clear_xd # family > 6, ok 85aa042141SBorislav Petkov jb .Lverify_cpu_check # family < 6, skip 86ae84739cSKees Cook 87ae84739cSKees Cook andl $0x000f00f0, %ecx # mask model and extended model 88ae84739cSKees Cook shrl $4, %ecx 89ae84739cSKees Cook cmpl $0xd, %ecx 90aa042141SBorislav Petkov jb .Lverify_cpu_check # family == 6, model < 0xd, skip 91ae84739cSKees Cook 92aa042141SBorislav Petkov.Lverify_cpu_clear_xd: 93ae84739cSKees Cook movl $MSR_IA32_MISC_ENABLE, %ecx 94ae84739cSKees Cook rdmsr 95ae84739cSKees Cook btrl $2, %edx # clear MSR_IA32_MISC_ENABLE_XD_DISABLE 96aa042141SBorislav Petkov jnc .Lverify_cpu_check # only write MSR if bit was changed 97ae84739cSKees Cook wrmsr 98ae84739cSKees Cook 99aa042141SBorislav Petkov.Lverify_cpu_check: 100c5cbac69SKees Cook movl $0x1,%eax # Does the cpu have what it takes 101c5cbac69SKees Cook cpuid 102c5cbac69SKees Cook andl $REQUIRED_MASK0,%edx 103c5cbac69SKees Cook xorl $REQUIRED_MASK0,%edx 104aa042141SBorislav Petkov jnz .Lverify_cpu_no_longmode 105c5cbac69SKees Cook 106c5cbac69SKees Cook movl $0x80000000,%eax # See if extended cpuid is implemented 107c5cbac69SKees Cook cpuid 108c5cbac69SKees Cook cmpl $0x80000001,%eax 109aa042141SBorislav Petkov jb .Lverify_cpu_no_longmode # no extended cpuid 110c5cbac69SKees Cook 111c5cbac69SKees Cook movl $0x80000001,%eax # Does the cpu have what it takes 112c5cbac69SKees Cook cpuid 113c5cbac69SKees Cook andl $REQUIRED_MASK1,%edx 114c5cbac69SKees Cook xorl $REQUIRED_MASK1,%edx 115aa042141SBorislav Petkov jnz .Lverify_cpu_no_longmode 116c5cbac69SKees Cook 117aa042141SBorislav Petkov.Lverify_cpu_sse_test: 118c5cbac69SKees Cook movl $1,%eax 119c5cbac69SKees Cook cpuid 120c5cbac69SKees Cook andl $SSE_MASK,%edx 121c5cbac69SKees Cook cmpl $SSE_MASK,%edx 122aa042141SBorislav Petkov je .Lverify_cpu_sse_ok 123c5cbac69SKees Cook test %di,%di 124aa042141SBorislav Petkov jz .Lverify_cpu_no_longmode # only try to force SSE on AMD 125c5cbac69SKees Cook movl $MSR_K7_HWCR,%ecx 126c5cbac69SKees Cook rdmsr 127c5cbac69SKees Cook btr $15,%eax # enable SSE 128c5cbac69SKees Cook wrmsr 129c5cbac69SKees Cook xor %di,%di # don't loop 130aa042141SBorislav Petkov jmp .Lverify_cpu_sse_test # try again 131c5cbac69SKees Cook 132aa042141SBorislav Petkov.Lverify_cpu_no_longmode: 13304633df0SBorislav Petkov popf # Restore caller passed flags 134c5cbac69SKees Cook movl $1,%eax 135*f94909ceSPeter Zijlstra RET 136aa042141SBorislav Petkov.Lverify_cpu_sse_ok: 13704633df0SBorislav Petkov popf # Restore caller passed flags 138c5cbac69SKees Cook xorl %eax, %eax 139*f94909ceSPeter Zijlstra RET 140ef77e688SJiri SlabySYM_FUNC_END(verify_cpu) 141