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

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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: Prashanth Nageshappa <prashanth@linux.vnet.ibm.com>
Signed-off-by: Masami 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: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Masami Hiramatsu 2012-04-13 12:24:27 +09:00 committed by Ingo Molnar
parent 7ea6411f4c
commit 6c7b8e82aa
1 changed files with 36 additions and 17 deletions
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53
arch/x86/lib/insn.c
View File

@ -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);