Commit 5901781a authored by Joerg Roedel's avatar Joerg Roedel Committed by Borislav Petkov
Browse files

x86/insn: Add insn_has_rep_prefix() helper 



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

Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Reviewed-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Link: https://lkml.kernel.org/r/20200907131613.12703-12-joro@8bytes.org
parent 7af1bd82

arch/x86/include/asm/insn-eval.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

arch/x86/lib/insn-eval.c

+24 −0
Original line number Diff line number Diff line
@@ -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

CRA Git | Maintained and supported by SUSTech CRA and CCSE