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Viewing changes to arch/x86/lib/copy_user_64.S

  • Committer: Package Import Robot
  • Author(s): John Rigby, John Rigby
  • Date: 2011-09-26 10:44:23 UTC
  • Revision ID: package-import@ubuntu.com-20110926104423-3o58a3c1bj7x00rs
Tags: 3.0.0-1007.9
https://launchpad.net/bugs/826021
[ John Rigby ]

Enable crypto modules and remove crypto-modules from
exclude-module files
LP: #826021

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arch/x86/lib/copy_user_64.S
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#include <asm/asm-offsets.h>
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#include <asm/thread_info.h>
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#include <asm/cpufeature.h>
 
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#include <asm/alternative-asm.h>
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        .macro ALTERNATIVE_JUMP feature,orig,alt
 
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/*
 
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 * By placing feature2 after feature1 in altinstructions section, we logically
 
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 * implement:
 
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 * If CPU has feature2, jmp to alt2 is used
 
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 * else if CPU has feature1, jmp to alt1 is used
 
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 * else jmp to orig is used.
 
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 */
 
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        .macro ALTERNATIVE_JUMP feature1,feature2,orig,alt1,alt2
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0:
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        .byte 0xe9      /* 32bit jump */
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        .long \orig-1f  /* by default jump to orig */
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1:
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        .section .altinstr_replacement,"ax"
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2:      .byte 0xe9                      /* near jump with 32bit immediate */
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        .long \alt-1b /* offset */   /* or alternatively to alt */
 
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        .long \alt1-1b /* offset */   /* or alternatively to alt1 */
 
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3:      .byte 0xe9                      /* near jump with 32bit immediate */
 
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        .long \alt2-1b /* offset */   /* or alternatively to alt2 */
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        .previous
 
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        .section .altinstructions,"a"
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        .align 8
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        .quad  0b
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        .quad  2b
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        .word  \feature                 /* when feature is set */
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        .byte  5
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        .byte  5
 
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        altinstruction_entry 0b,2b,\feature1,5,5
 
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        altinstruction_entry 0b,3b,\feature2,5,5
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        .previous
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        .endm
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        jc bad_to_user
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        cmpq TI_addr_limit(%rax),%rcx
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        ja bad_to_user
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        ALTERNATIVE_JUMP X86_FEATURE_REP_GOOD,copy_user_generic_unrolled,copy_user_generic_string
 
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        ALTERNATIVE_JUMP X86_FEATURE_REP_GOOD,X86_FEATURE_ERMS, \
 
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                copy_user_generic_unrolled,copy_user_generic_string,    \
 
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                copy_user_enhanced_fast_string
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        CFI_ENDPROC
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ENDPROC(_copy_to_user)
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        jc bad_from_user
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        cmpq TI_addr_limit(%rax),%rcx
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        ja bad_from_user
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        ALTERNATIVE_JUMP X86_FEATURE_REP_GOOD,copy_user_generic_unrolled,copy_user_generic_string
 
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        ALTERNATIVE_JUMP X86_FEATURE_REP_GOOD,X86_FEATURE_ERMS, \
 
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                copy_user_generic_unrolled,copy_user_generic_string,    \
 
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                copy_user_enhanced_fast_string
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        CFI_ENDPROC
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ENDPROC(_copy_from_user)
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        .previous
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        CFI_ENDPROC
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ENDPROC(copy_user_generic_string)
 
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/*
 
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 * Some CPUs are adding enhanced REP MOVSB/STOSB instructions.
 
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 * It's recommended to use enhanced REP MOVSB/STOSB if it's enabled.
 
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 *
 
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 * Input:
 
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 * rdi destination
 
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 * rsi source
 
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 * rdx count
 
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 *
 
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 * Output:
 
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 * eax uncopied bytes or 0 if successful.
 
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 */
 
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ENTRY(copy_user_enhanced_fast_string)
 
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        CFI_STARTPROC
 
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        andl %edx,%edx
 
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        jz 2f
 
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        movl %edx,%ecx
 
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1:      rep
 
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        movsb
 
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2:      xorl %eax,%eax
 
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        ret
 
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        .section .fixup,"ax"
 
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12:     movl %ecx,%edx          /* ecx is zerorest also */
 
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        jmp copy_user_handle_tail
 
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        .previous
 
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        .section __ex_table,"a"
 
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        .align 8
 
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        .quad 1b,12b
 
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        .previous
 
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        CFI_ENDPROC
 
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ENDPROC(copy_user_enhanced_fast_string)