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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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132ec92f3f
native_{rdmsr,wrmsr}_safe_regs are two new interfaces which allow
presetting of a subset of eight x86 GPRs before executing the rd/wrmsr
instructions. This is needed at least on AMD K8 for accessing an erratum
workaround MSR.
Originally based on an idea by H. Peter Anvin.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
LKML-Reference: <1251705011-18636-1-git-send-email-petkovbb@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
99 lines
1.8 KiB
ArmAsm
99 lines
1.8 KiB
ArmAsm
#include <linux/linkage.h>
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#include <linux/errno.h>
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#include <asm/asm.h>
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#include <asm/msr.h>
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#ifdef CONFIG_X86_64
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/*
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* int native_{rdmsr,wrmsr}_safe_regs(u32 gprs[8]);
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*
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* reg layout: u32 gprs[eax, ecx, edx, ebx, esp, ebp, esi, edi]
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*
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*/
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.macro op_safe_regs op:req
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ENTRY(native_\op\()_safe_regs)
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push %rbx
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push %rbp
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push $0 /* Return value */
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push %rdi
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movl (%rdi), %eax
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movl 4(%rdi), %ecx
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movl 8(%rdi), %edx
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movl 12(%rdi), %ebx
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movl 20(%rdi), %ebp
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movl 24(%rdi), %esi
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movl 28(%rdi), %edi
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1: \op
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2: movl %edi, %r10d
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pop %rdi
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movl %eax, (%rdi)
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movl %ecx, 4(%rdi)
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movl %edx, 8(%rdi)
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movl %ebx, 12(%rdi)
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movl %ebp, 20(%rdi)
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movl %esi, 24(%rdi)
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movl %r10d, 28(%rdi)
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pop %rax
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pop %rbp
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pop %rbx
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ret
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3:
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movq $-EIO, 8(%rsp)
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jmp 2b
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.section __ex_table,"ax"
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.balign 4
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.quad 1b, 3b
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.previous
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ENDPROC(native_\op\()_safe_regs)
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.endm
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#else /* X86_32 */
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.macro op_safe_regs op:req
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ENTRY(native_\op\()_safe_regs)
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push %ebx
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push %ebp
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push %esi
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push %edi
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push $0 /* Return value */
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push %eax
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movl 4(%eax), %ecx
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movl 8(%eax), %edx
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movl 12(%eax), %ebx
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movl 20(%eax), %ebp
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movl 24(%eax), %esi
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movl 28(%eax), %edi
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movl (%eax), %eax
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1: \op
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2: push %eax
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movl 4(%esp), %eax
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pop (%eax)
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addl $4, %esp
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movl %ecx, 4(%eax)
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movl %edx, 8(%eax)
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movl %ebx, 12(%eax)
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movl %ebp, 20(%eax)
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movl %esi, 24(%eax)
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movl %edi, 28(%eax)
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pop %eax
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pop %edi
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pop %esi
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pop %ebp
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pop %ebx
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ret
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3:
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movl $-EIO, 4(%esp)
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jmp 2b
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.section __ex_table,"ax"
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.balign 4
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.long 1b, 3b
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.previous
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ENDPROC(native_\op\()_safe_regs)
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.endm
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#endif
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op_safe_regs rdmsr
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op_safe_regs wrmsr
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