Re: [PATCH 09/70] x86/insn: Add insn_rep_prefix() helper

Masami Hiramatsu
2020-03-27T03:56:41Z

On Thu, 19 Mar 2020 10:13:06 +0100
Joerg Roedel <joro@8bytes.org> wrote:

> 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 1e343010129e..41dee0faae97 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_rep_prefix(struct insn *insn);

Can you make it "insn_has_rep_prefix()"?

Thank you,

> 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 f18260a19960..5d98dff5a2d7 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_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_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
> --
> 2.17.1
>

--
Masami Hiramatsu <mhiramat@kernel.org>