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    Subject[PATCH v4 10/75] x86/insn: Add insn_has_rep_prefix() helper
    Date
    From: Joerg Roedel <jroedel@suse.de>

    Add a function to check whether an instruction has a REP prefix.

    Signed-off-by: Joerg Roedel <jroedel@suse.de>
    ---
    arch/x86/include/asm/insn-eval.h | 1 +
    arch/x86/lib/insn-eval.c | 24 ++++++++++++++++++++++++
    2 files changed, 25 insertions(+)

    diff --git a/arch/x86/include/asm/insn-eval.h b/arch/x86/include/asm/insn-eval.h
    index f748f57f1491..a0f839aa144d 100644
    --- a/arch/x86/include/asm/insn-eval.h
    +++ b/arch/x86/include/asm/insn-eval.h
    @@ -15,6 +15,7 @@
    #define INSN_CODE_SEG_OPND_SZ(params) (params & 0xf)
    #define INSN_CODE_SEG_PARAMS(oper_sz, addr_sz) (oper_sz | (addr_sz << 4))

    +bool insn_has_rep_prefix(struct insn *insn);
    void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs);
    int insn_get_modrm_rm_off(struct insn *insn, struct pt_regs *regs);
    int insn_get_modrm_reg_off(struct insn *insn, struct pt_regs *regs);
    diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c
    index a8ac5c5e94f0..8ed9d645259c 100644
    --- a/arch/x86/lib/insn-eval.c
    +++ b/arch/x86/lib/insn-eval.c
    @@ -53,6 +53,30 @@ static bool is_string_insn(struct insn *insn)
    }
    }

    +/**
    + * insn_has_rep_prefix() - Determine if instruction has a REP prefix
    + * @insn: Instruction containing the prefix to inspect
    + *
    + * Returns:
    + *
    + * true if the instruction has a REP prefix, false if not.
    + */
    +bool insn_has_rep_prefix(struct insn *insn)
    +{
    + int i;
    +
    + insn_get_prefixes(insn);
    +
    + for (i = 0; i < insn->prefixes.nbytes; i++) {
    + insn_byte_t p = insn->prefixes.bytes[i];
    +
    + if (p == 0xf2 || p == 0xf3)
    + return true;
    + }
    +
    + return false;
    +}
    +
    /**
    * get_seg_reg_override_idx() - obtain segment register override index
    * @insn: Valid instruction with segment override prefixes
    --
    2.27.0
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