Commit 6c7b8e82 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Ingo Molnar
Browse files

x86: Handle failures of parsing immediate operands in the instruction decoder 



This can happen if the instruction is much longer than the maximum length,
or if insn->opnd_bytes is manually changed.

This patch also fixes warnings from -Wswitch-default flag.

Reported-by: default avatarPrashanth Nageshappa <prashanth@linux.vnet.ibm.com>
Signed-off-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@linux.vnet.ibm.com>
Cc: Linux-mm <linux-mm@kvack.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Anton Arapov <anton@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: yrl.pp-manager.tt@hitachi.com
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120413032427.32577.42602.stgit@localhost.localdomain


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 7ea6411f

arch/x86/lib/insn.c

+36 −17
Original line number Diff line number Diff line
@@ -379,8 +379,8 @@ err_out: 
	return;

}



/* Decode moffset16/32/64 */

static void __get_moffset(struct insn *insn)

/* Decode moffset16/32/64. Return 0 if failed */

static int __get_moffset(struct insn *insn)

{

	switch (insn->addr_bytes) {

	case 2:
@@ -397,15 +397,19 @@ static void __get_moffset(struct insn *insn) 
		insn->moffset2.value = get_next(int, insn);

		insn->moffset2.nbytes = 4;

		break;

	default:	/* opnd_bytes must be modified manually */

		goto err_out;

	}

	insn->moffset1.got = insn->moffset2.got = 1;



	return 1;



err_out:

	return;

	return 0;

}



/* Decode imm v32(Iz) */

static void __get_immv32(struct insn *insn)

/* Decode imm v32(Iz). Return 0 if failed */

static int __get_immv32(struct insn *insn)

{

	switch (insn->opnd_bytes) {

	case 2:
@@ -417,14 +421,18 @@ static void __get_immv32(struct insn *insn) 
		insn->immediate.value = get_next(int, insn);

		insn->immediate.nbytes = 4;

		break;

	default:	/* opnd_bytes must be modified manually */

		goto err_out;

	}



	return 1;



err_out:

	return;

	return 0;

}



/* Decode imm v64(Iv/Ov) */

static void __get_immv(struct insn *insn)

/* Decode imm v64(Iv/Ov), Return 0 if failed */

static int __get_immv(struct insn *insn)

{

	switch (insn->opnd_bytes) {

	case 2:
@@ -441,15 +449,18 @@ static void __get_immv(struct insn *insn) 
		insn->immediate2.value = get_next(int, insn);

		insn->immediate2.nbytes = 4;

		break;

	default:	/* opnd_bytes must be modified manually */

		goto err_out;

	}

	insn->immediate1.got = insn->immediate2.got = 1;



	return 1;

err_out:

	return;

	return 0;

}



/* Decode ptr16:16/32(Ap) */

static void __get_immptr(struct insn *insn)

static int __get_immptr(struct insn *insn)

{

	switch (insn->opnd_bytes) {

	case 2:
@@ -462,14 +473,17 @@ static void __get_immptr(struct insn *insn) 
		break;

	case 8:

		/* ptr16:64 is not exist (no segment) */

		return;

		return 0;

	default:	/* opnd_bytes must be modified manually */

		goto err_out;

	}

	insn->immediate2.value = get_next(unsigned short, insn);

	insn->immediate2.nbytes = 2;

	insn->immediate1.got = insn->immediate2.got = 1;



	return 1;

err_out:

	return;

	return 0;

}



/**
@@ -489,7 +503,8 @@ void insn_get_immediate(struct insn *insn) 
		insn_get_displacement(insn);



	if (inat_has_moffset(insn->attr)) {

		__get_moffset(insn);

		if (!__get_moffset(insn))

			goto err_out;

		goto done;

	}
@@ -517,16 +532,20 @@ void insn_get_immediate(struct insn *insn) 
		insn->immediate2.nbytes = 4;

		break;

	case INAT_IMM_PTR:

		__get_immptr(insn);

		if (!__get_immptr(insn))

			goto err_out;

		break;

	case INAT_IMM_VWORD32:

		__get_immv32(insn);

		if (!__get_immv32(insn))

			goto err_out;

		break;

	case INAT_IMM_VWORD:

		__get_immv(insn);

		if (!__get_immv(insn))

			goto err_out;

		break;

	default:

		break;

		/* Here, insn must have an immediate, but failed */

		goto err_out;

	}

	if (inat_has_second_immediate(insn->attr)) {

		insn->immediate2.value = get_next(char, insn);

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