Re: [PATCH v2 04/21] x86/insn: Add an insn_decode() API
From: Masami Hiramatsu
Date: Sun Feb 28 2021 - 09:57:01 EST
On 2021年2月26日 19:30:06 +0100
Borislav Petkov <bp@xxxxxxxxx> wrote:
>
On Sat, Feb 27, 2021 at 12:45:06AM +0900, Masami Hiramatsu wrote:
>
> OK, but I think it should return -EINVAL or -EILSEQ for bad instruction.
>
>
It does return -EINVAL when insn_complete() returns 0.
>
>
> Here you return 1 for a bad opcode.
>
>
Whoops, that's a leftover from the early version where it would return
>
!0 on error. Lemme fix that.
>
>
> Ditto.
>
> Would you mean -EINVAL?
>
>
Yap.
>
>
> Also, __get_*() functions are expected to return bool (1/0)
>
> for checking bad data. See insn_get_immediate() INAT_IMM_PTR case for example.
>
>
Yuck, I totally snafu'ed that, sorry ;-\
>
>
Ok, see below. The patterns look correct now, I'll give it another look
>
tomorrow again, to make sure I haven't missed anything.
>
>
Thx for catching those!
Thank you for fixing!
>
>
---
>
From: Borislav Petkov <bp@xxxxxxx>
>
Date: Tue, 3 Nov 2020 17:28:30 +0100
>
Subject: [PATCH] x86/insn: Add an insn_decode() API
>
>
Users of the instruction decoder should use this to decode instruction
>
bytes. For that, have insn*() helpers return an int value to denote
>
success/failure. When there's an error fetching the next insn byte and
>
the insn falls short, return -ENODATA to denote that.
>
>
While at it, make insn_get_opcode() more stricter as to whether what has
>
seen so far is a valid insn and if not.
>
>
Copy linux/kconfig.h for the tools-version of the decoder so that it can
>
use IS_ENABLED().
>
>
Also, cast the INSN_MODE_KERN dummy define value to (enum insn_mode)
>
for tools use of the decoder because perf tool builds with -Werror and
>
errors out with -Werror=sign-compare otherwise.
>
This version looks good to me.
Acked-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Thank you!
>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
>
---
>
arch/x86/include/asm/insn.h | 24 +++-
>
arch/x86/lib/insn.c | 216 +++++++++++++++++++++++------
>
tools/arch/x86/include/asm/insn.h | 24 +++-
>
tools/arch/x86/lib/insn.c | 222 +++++++++++++++++++++++-------
>
tools/include/linux/kconfig.h | 73 ++++++++++
>
5 files changed, 452 insertions(+), 107 deletions(-)
>
create mode 100644 tools/include/linux/kconfig.h
>
>
diff --git a/arch/x86/include/asm/insn.h b/arch/x86/include/asm/insn.h
>
index 17c130f1ba57..546436b3c215 100644
>
--- a/arch/x86/include/asm/insn.h
>
+++ b/arch/x86/include/asm/insn.h
>
@@ -87,13 +87,23 @@ struct insn {
>
#define X86_VEX_M_MAX 0x1f /* VEX3.M Maximum value */
>
>
extern void insn_init(struct insn *insn, const void *kaddr, int buf_len, int x86_64);
>
-extern void insn_get_prefixes(struct insn *insn);
>
-extern void insn_get_opcode(struct insn *insn);
>
-extern void insn_get_modrm(struct insn *insn);
>
-extern void insn_get_sib(struct insn *insn);
>
-extern void insn_get_displacement(struct insn *insn);
>
-extern void insn_get_immediate(struct insn *insn);
>
-extern void insn_get_length(struct insn *insn);
>
+extern int insn_get_prefixes(struct insn *insn);
>
+extern int insn_get_opcode(struct insn *insn);
>
+extern int insn_get_modrm(struct insn *insn);
>
+extern int insn_get_sib(struct insn *insn);
>
+extern int insn_get_displacement(struct insn *insn);
>
+extern int insn_get_immediate(struct insn *insn);
>
+extern int insn_get_length(struct insn *insn);
>
+
>
+enum insn_mode {
>
+ INSN_MODE_32,
>
+ INSN_MODE_64,
>
+ /* Mode is determined by the current kernel build. */
>
+ INSN_MODE_KERN,
>
+ INSN_NUM_MODES,
>
+};
>
+
>
+extern int insn_decode(struct insn *insn, const void *kaddr, int buf_len, enum insn_mode m);
>
>
/* Attribute will be determined after getting ModRM (for opcode groups) */
>
static inline void insn_get_attribute(struct insn *insn)
>
diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c
>
index 745c704f7c78..9a395c39a0c0 100644
>
--- a/arch/x86/lib/insn.c
>
+++ b/arch/x86/lib/insn.c
>
@@ -13,6 +13,9 @@
>
#include <asm/inat.h> /*__ignore_sync_check__ */
>
#include <asm/insn.h> /* __ignore_sync_check__ */
>
>
+#include <linux/errno.h>
>
+#include <linux/kconfig.h>
>
+
>
#include <asm/emulate_prefix.h> /* __ignore_sync_check__ */
>
>
/* Verify next sizeof(t) bytes can be on the same instruction */
>
@@ -98,8 +101,12 @@ static void insn_get_emulate_prefix(struct insn *insn)
>
* Populates the @insn->prefixes bitmap, and updates @insn->next_byte
>
* to point to the (first) opcode. No effect if @insn->prefixes.got
>
* is already set.
>
+ *
>
+ * * Returns:
>
+ * 0: on success
>
+ * < 0: on error
>
*/
>
-void insn_get_prefixes(struct insn *insn)
>
+int insn_get_prefixes(struct insn *insn)
>
{
>
struct insn_field *prefixes = &insn->prefixes;
>
insn_attr_t attr;
>
@@ -107,7 +114,7 @@ void insn_get_prefixes(struct insn *insn)
>
int i, nb;
>
>
if (prefixes->got)
>
- return;
>
+ return 0;
>
>
insn_get_emulate_prefix(insn);
>
>
@@ -218,8 +225,10 @@ void insn_get_prefixes(struct insn *insn)
>
>
prefixes->got = 1;
>
>
+ return 0;
>
+
>
err_out:
>
- return;
>
+ return -ENODATA;
>
}
>
>
/**
>
@@ -231,16 +240,25 @@ void insn_get_prefixes(struct insn *insn)
>
* If necessary, first collects any preceding (prefix) bytes.
>
* Sets @insn->opcode.value = opcode1. No effect if @insn->opcode.got
>
* is already 1.
>
+ *
>
+ * Returns:
>
+ * 0: on success
>
+ * < 0: on error
>
*/
>
-void insn_get_opcode(struct insn *insn)
>
+int insn_get_opcode(struct insn *insn)
>
{
>
struct insn_field *opcode = &insn->opcode;
>
+ int pfx_id, ret;
>
insn_byte_t op;
>
- int pfx_id;
>
+
>
if (opcode->got)
>
- return;
>
- if (!insn->prefixes.got)
>
- insn_get_prefixes(insn);
>
+ return 0;
>
+
>
+ if (!insn->prefixes.got) {
>
+ ret = insn_get_prefixes(insn);
>
+ if (ret)
>
+ return ret;
>
+ }
>
>
/* Get first opcode */
>
op = get_next(insn_byte_t, insn);
>
@@ -255,9 +273,13 @@ void insn_get_opcode(struct insn *insn)
>
insn->attr = inat_get_avx_attribute(op, m, p);
>
if ((inat_must_evex(insn->attr) && !insn_is_evex(insn)) ||
>
(!inat_accept_vex(insn->attr) &&
>
- !inat_is_group(insn->attr)))
>
- insn->attr = 0; /* This instruction is bad */
>
- goto end; /* VEX has only 1 byte for opcode */
>
+ !inat_is_group(insn->attr))) {
>
+ /* This instruction is bad */
>
+ insn->attr = 0;
>
+ return -EINVAL;
>
+ }
>
+ /* VEX has only 1 byte for opcode */
>
+ goto end;
>
}
>
>
insn->attr = inat_get_opcode_attribute(op);
>
@@ -268,13 +290,18 @@ void insn_get_opcode(struct insn *insn)
>
pfx_id = insn_last_prefix_id(insn);
>
insn->attr = inat_get_escape_attribute(op, pfx_id, insn->attr);
>
}
>
- if (inat_must_vex(insn->attr))
>
- insn->attr = 0; /* This instruction is bad */
>
+
>
+ if (inat_must_vex(insn->attr)) {
>
+ /* This instruction is bad */
>
+ insn->attr = 0;
>
+ return -EINVAL;
>
+ }
>
end:
>
opcode->got = 1;
>
+ return 0;
>
>
err_out:
>
- return;
>
+ return -ENODATA;
>
}
>
>
/**
>
@@ -284,15 +311,25 @@ void insn_get_opcode(struct insn *insn)
>
* Populates @insn->modrm and updates @insn->next_byte to point past the
>
* ModRM byte, if any. If necessary, first collects the preceding bytes
>
* (prefixes and opcode(s)). No effect if @insn->modrm.got is already 1.
>
+ *
>
+ * Returns:
>
+ * 0: on success
>
+ * < 0: on error
>
*/
>
-void insn_get_modrm(struct insn *insn)
>
+int insn_get_modrm(struct insn *insn)
>
{
>
struct insn_field *modrm = &insn->modrm;
>
insn_byte_t pfx_id, mod;
>
+ int ret;
>
+
>
if (modrm->got)
>
- return;
>
- if (!insn->opcode.got)
>
- insn_get_opcode(insn);
>
+ return 0;
>
+
>
+ if (!insn->opcode.got) {
>
+ ret = insn_get_opcode(insn);
>
+ if (ret)
>
+ return ret;
>
+ }
>
>
if (inat_has_modrm(insn->attr)) {
>
mod = get_next(insn_byte_t, insn);
>
@@ -302,17 +339,22 @@ void insn_get_modrm(struct insn *insn)
>
pfx_id = insn_last_prefix_id(insn);
>
insn->attr = inat_get_group_attribute(mod, pfx_id,
>
insn->attr);
>
- if (insn_is_avx(insn) && !inat_accept_vex(insn->attr))
>
- insn->attr = 0; /* This is bad */
>
+ if (insn_is_avx(insn) && !inat_accept_vex(insn->attr)) {
>
+ /* Bad insn */
>
+ insn->attr = 0;
>
+ return -EINVAL;
>
+ }
>
}
>
}
>
>
if (insn->x86_64 && inat_is_force64(insn->attr))
>
insn->opnd_bytes = 8;
>
+
>
modrm->got = 1;
>
+ return 0;
>
>
err_out:
>
- return;
>
+ return -ENODATA;
>
}
>
>
>
@@ -326,11 +368,16 @@ void insn_get_modrm(struct insn *insn)
>
int insn_rip_relative(struct insn *insn)
>
{
>
struct insn_field *modrm = &insn->modrm;
>
+ int ret;
>
>
if (!insn->x86_64)
>
return 0;
>
- if (!modrm->got)
>
- insn_get_modrm(insn);
>
+
>
+ if (!modrm->got) {
>
+ ret = insn_get_modrm(insn);
>
+ if (ret)
>
+ return 0;
>
+ }
>
/*
>
* For rip-relative instructions, the mod field (top 2 bits)
>
* is zero and the r/m field (bottom 3 bits) is 0x5.
>
@@ -344,15 +391,25 @@ int insn_rip_relative(struct insn *insn)
>
*
>
* If necessary, first collects the instruction up to and including the
>
* ModRM byte.
>
+ *
>
+ * Returns:
>
+ * 0: if decoding succeeded
>
+ * < 0: otherwise.
>
*/
>
-void insn_get_sib(struct insn *insn)
>
+int insn_get_sib(struct insn *insn)
>
{
>
insn_byte_t modrm;
>
+ int ret;
>
>
if (insn->sib.got)
>
- return;
>
- if (!insn->modrm.got)
>
- insn_get_modrm(insn);
>
+ return 0;
>
+
>
+ if (!insn->modrm.got) {
>
+ ret = insn_get_modrm(insn);
>
+ if (ret)
>
+ return ret;
>
+ }
>
+
>
if (insn->modrm.nbytes) {
>
modrm = (insn_byte_t)insn->modrm.value;
>
if (insn->addr_bytes != 2 &&
>
@@ -363,8 +420,10 @@ void insn_get_sib(struct insn *insn)
>
}
>
insn->sib.got = 1;
>
>
+ return 0;
>
+
>
err_out:
>
- return;
>
+ return -ENODATA;
>
}
>
>
>
@@ -375,15 +434,25 @@ void insn_get_sib(struct insn *insn)
>
* If necessary, first collects the instruction up to and including the
>
* SIB byte.
>
* Displacement value is sign-expanded.
>
+ *
>
+ * * Returns:
>
+ * 0: if decoding succeeded
>
+ * < 0: otherwise.
>
*/
>
-void insn_get_displacement(struct insn *insn)
>
+int insn_get_displacement(struct insn *insn)
>
{
>
insn_byte_t mod, rm, base;
>
+ int ret;
>
>
if (insn->displacement.got)
>
- return;
>
- if (!insn->sib.got)
>
- insn_get_sib(insn);
>
+ return 0;
>
+
>
+ if (!insn->sib.got) {
>
+ ret = insn_get_sib(insn);
>
+ if (ret)
>
+ return ret;
>
+ }
>
+
>
if (insn->modrm.nbytes) {
>
/*
>
* Interpreting the modrm byte:
>
@@ -426,9 +495,10 @@ void insn_get_displacement(struct insn *insn)
>
}
>
out:
>
insn->displacement.got = 1;
>
+ return 0;
>
>
err_out:
>
- return;
>
+ return -ENODATA;
>
}
>
>
/* Decode moffset16/32/64. Return 0 if failed */
>
@@ -539,20 +609,30 @@ static int __get_immptr(struct insn *insn)
>
}
>
>
/**
>
- * insn_get_immediate() - Get the immediates of instruction
>
+ * insn_get_immediate() - Get the immediate in an instruction
>
* @insn: &struct insn containing instruction
>
*
>
* If necessary, first collects the instruction up to and including the
>
* displacement bytes.
>
* Basically, most of immediates are sign-expanded. Unsigned-value can be
>
- * get by bit masking with ((1 << (nbytes * 8)) - 1)
>
+ * computed by bit masking with ((1 << (nbytes * 8)) - 1)
>
+ *
>
+ * Returns:
>
+ * 0: on success
>
+ * < 0: on error
>
*/
>
-void insn_get_immediate(struct insn *insn)
>
+int insn_get_immediate(struct insn *insn)
>
{
>
+ int ret;
>
+
>
if (insn->immediate.got)
>
- return;
>
- if (!insn->displacement.got)
>
- insn_get_displacement(insn);
>
+ return 0;
>
+
>
+ if (!insn->displacement.got) {
>
+ ret = insn_get_displacement(insn);
>
+ if (ret)
>
+ return ret;
>
+ }
>
>
if (inat_has_moffset(insn->attr)) {
>
if (!__get_moffset(insn))
>
@@ -605,9 +685,10 @@ void insn_get_immediate(struct insn *insn)
>
}
>
done:
>
insn->immediate.got = 1;
>
+ return 0;
>
>
err_out:
>
- return;
>
+ return -ENODATA;
>
}
>
>
/**
>
@@ -616,13 +697,58 @@ void insn_get_immediate(struct insn *insn)
>
*
>
* If necessary, first collects the instruction up to and including the
>
* immediates bytes.
>
- */
>
-void insn_get_length(struct insn *insn)
>
+ *
>
+ * Returns:
>
+ * - 0 on success
>
+ * - < 0 on error
>
+*/
>
+int insn_get_length(struct insn *insn)
>
{
>
+ int ret;
>
+
>
if (insn->length)
>
- return;
>
- if (!insn->immediate.got)
>
- insn_get_immediate(insn);
>
+ return 0;
>
+
>
+ if (!insn->immediate.got) {
>
+ ret = insn_get_immediate(insn);
>
+ if (ret)
>
+ return ret;
>
+ }
>
+
>
insn->length = (unsigned char)((unsigned long)insn->next_byte
>
- (unsigned long)insn->kaddr);
>
+
>
+ return 0;
>
+}
>
+
>
+/**
>
+ * insn_decode() - Decode an x86 instruction
>
+ * @insn: &struct insn to be initialized
>
+ * @kaddr: address (in kernel memory) of instruction (or copy thereof)
>
+ * @buf_len: length of the insn buffer at @kaddr
>
+ * @m: insn mode, see enum insn_mode
>
+ *
>
+ * Returns:
>
+ * 0: if decoding succeeded
>
+ * < 0: otherwise.
>
+ */
>
+int insn_decode(struct insn *insn, const void *kaddr, int buf_len, enum insn_mode m)
>
+{
>
+ int ret;
>
+
>
+/* #define INSN_MODE_KERN -1 __ignore_sync_check__ mode is only valid in the kernel */
>
+
>
+ if (m == INSN_MODE_KERN)
>
+ insn_init(insn, kaddr, buf_len, IS_ENABLED(CONFIG_X86_64));
>
+ else
>
+ insn_init(insn, kaddr, buf_len, m == INSN_MODE_64);
>
+
>
+ ret = insn_get_length(insn);
>
+ if (ret)
>
+ return ret;
>
+
>
+ if (insn_complete(insn))
>
+ return 0;
>
+
>
+ return -EINVAL;
>
}
>
diff --git a/tools/arch/x86/include/asm/insn.h b/tools/arch/x86/include/asm/insn.h
>
index 33d41982a5dd..621ab64a6d27 100644
>
--- a/tools/arch/x86/include/asm/insn.h
>
+++ b/tools/arch/x86/include/asm/insn.h
>
@@ -87,13 +87,23 @@ struct insn {
>
#define X86_VEX_M_MAX 0x1f /* VEX3.M Maximum value */
>
>
extern void insn_init(struct insn *insn, const void *kaddr, int buf_len, int x86_64);
>
-extern void insn_get_prefixes(struct insn *insn);
>
-extern void insn_get_opcode(struct insn *insn);
>
-extern void insn_get_modrm(struct insn *insn);
>
-extern void insn_get_sib(struct insn *insn);
>
-extern void insn_get_displacement(struct insn *insn);
>
-extern void insn_get_immediate(struct insn *insn);
>
-extern void insn_get_length(struct insn *insn);
>
+extern int insn_get_prefixes(struct insn *insn);
>
+extern int insn_get_opcode(struct insn *insn);
>
+extern int insn_get_modrm(struct insn *insn);
>
+extern int insn_get_sib(struct insn *insn);
>
+extern int insn_get_displacement(struct insn *insn);
>
+extern int insn_get_immediate(struct insn *insn);
>
+extern int insn_get_length(struct insn *insn);
>
+
>
+enum insn_mode {
>
+ INSN_MODE_32,
>
+ INSN_MODE_64,
>
+ /* Mode is determined by the current kernel build. */
>
+ INSN_MODE_KERN,
>
+ INSN_NUM_MODES,
>
+};
>
+
>
+extern int insn_decode(struct insn *insn, const void *kaddr, int buf_len, enum insn_mode m);
>
>
/* Attribute will be determined after getting ModRM (for opcode groups) */
>
static inline void insn_get_attribute(struct insn *insn)
>
diff --git a/tools/arch/x86/lib/insn.c b/tools/arch/x86/lib/insn.c
>
index dedcfd67f90c..155e50aefd84 100644
>
--- a/tools/arch/x86/lib/insn.c
>
+++ b/tools/arch/x86/lib/insn.c
>
@@ -10,10 +10,13 @@
>
#else
>
#include <string.h>
>
#endif
>
-#include "../include/asm/inat.h" /* __ignore_sync_check__ */
>
-#include "../include/asm/insn.h" /* __ignore_sync_check__ */
>
+#include <asm/inat.h> /*__ignore_sync_check__ */
>
+#include <asm/insn.h> /* __ignore_sync_check__ */
>
>
-#include "../include/asm/emulate_prefix.h" /* __ignore_sync_check__ */
>
+#include <linux/errno.h>
>
+#include <linux/kconfig.h>
>
+
>
+#include <asm/emulate_prefix.h> /* __ignore_sync_check__ */
>
>
/* Verify next sizeof(t) bytes can be on the same instruction */
>
#define validate_next(t, insn, n) \
>
@@ -98,8 +101,12 @@ static void insn_get_emulate_prefix(struct insn *insn)
>
* Populates the @insn->prefixes bitmap, and updates @insn->next_byte
>
* to point to the (first) opcode. No effect if @insn->prefixes.got
>
* is already set.
>
+ *
>
+ * * Returns:
>
+ * 0: on success
>
+ * < 0: on error
>
*/
>
-void insn_get_prefixes(struct insn *insn)
>
+int insn_get_prefixes(struct insn *insn)
>
{
>
struct insn_field *prefixes = &insn->prefixes;
>
insn_attr_t attr;
>
@@ -107,7 +114,7 @@ void insn_get_prefixes(struct insn *insn)
>
int i, nb;
>
>
if (prefixes->got)
>
- return;
>
+ return 0;
>
>
insn_get_emulate_prefix(insn);
>
>
@@ -218,8 +225,10 @@ void insn_get_prefixes(struct insn *insn)
>
>
prefixes->got = 1;
>
>
+ return 0;
>
+
>
err_out:
>
- return;
>
+ return -ENODATA;
>
}
>
>
/**
>
@@ -231,16 +240,25 @@ void insn_get_prefixes(struct insn *insn)
>
* If necessary, first collects any preceding (prefix) bytes.
>
* Sets @insn->opcode.value = opcode1. No effect if @insn->opcode.got
>
* is already 1.
>
+ *
>
+ * Returns:
>
+ * 0: on success
>
+ * < 0: on error
>
*/
>
-void insn_get_opcode(struct insn *insn)
>
+int insn_get_opcode(struct insn *insn)
>
{
>
struct insn_field *opcode = &insn->opcode;
>
+ int pfx_id, ret;
>
insn_byte_t op;
>
- int pfx_id;
>
+
>
if (opcode->got)
>
- return;
>
- if (!insn->prefixes.got)
>
- insn_get_prefixes(insn);
>
+ return 0;
>
+
>
+ if (!insn->prefixes.got) {
>
+ ret = insn_get_prefixes(insn);
>
+ if (ret)
>
+ return ret;
>
+ }
>
>
/* Get first opcode */
>
op = get_next(insn_byte_t, insn);
>
@@ -255,9 +273,13 @@ void insn_get_opcode(struct insn *insn)
>
insn->attr = inat_get_avx_attribute(op, m, p);
>
if ((inat_must_evex(insn->attr) && !insn_is_evex(insn)) ||
>
(!inat_accept_vex(insn->attr) &&
>
- !inat_is_group(insn->attr)))
>
- insn->attr = 0; /* This instruction is bad */
>
- goto end; /* VEX has only 1 byte for opcode */
>
+ !inat_is_group(insn->attr))) {
>
+ /* This instruction is bad */
>
+ insn->attr = 0;
>
+ return -EINVAL;
>
+ }
>
+ /* VEX has only 1 byte for opcode */
>
+ goto end;
>
}
>
>
insn->attr = inat_get_opcode_attribute(op);
>
@@ -268,13 +290,18 @@ void insn_get_opcode(struct insn *insn)
>
pfx_id = insn_last_prefix_id(insn);
>
insn->attr = inat_get_escape_attribute(op, pfx_id, insn->attr);
>
}
>
- if (inat_must_vex(insn->attr))
>
- insn->attr = 0; /* This instruction is bad */
>
+
>
+ if (inat_must_vex(insn->attr)) {
>
+ /* This instruction is bad */
>
+ insn->attr = 0;
>
+ return -EINVAL;
>
+ }
>
end:
>
opcode->got = 1;
>
+ return 0;
>
>
err_out:
>
- return;
>
+ return -ENODATA;
>
}
>
>
/**
>
@@ -284,15 +311,25 @@ void insn_get_opcode(struct insn *insn)
>
* Populates @insn->modrm and updates @insn->next_byte to point past the
>
* ModRM byte, if any. If necessary, first collects the preceding bytes
>
* (prefixes and opcode(s)). No effect if @insn->modrm.got is already 1.
>
+ *
>
+ * Returns:
>
+ * 0: on success
>
+ * < 0: on error
>
*/
>
-void insn_get_modrm(struct insn *insn)
>
+int insn_get_modrm(struct insn *insn)
>
{
>
struct insn_field *modrm = &insn->modrm;
>
insn_byte_t pfx_id, mod;
>
+ int ret;
>
+
>
if (modrm->got)
>
- return;
>
- if (!insn->opcode.got)
>
- insn_get_opcode(insn);
>
+ return 0;
>
+
>
+ if (!insn->opcode.got) {
>
+ ret = insn_get_opcode(insn);
>
+ if (ret)
>
+ return ret;
>
+ }
>
>
if (inat_has_modrm(insn->attr)) {
>
mod = get_next(insn_byte_t, insn);
>
@@ -302,17 +339,22 @@ void insn_get_modrm(struct insn *insn)
>
pfx_id = insn_last_prefix_id(insn);
>
insn->attr = inat_get_group_attribute(mod, pfx_id,
>
insn->attr);
>
- if (insn_is_avx(insn) && !inat_accept_vex(insn->attr))
>
- insn->attr = 0; /* This is bad */
>
+ if (insn_is_avx(insn) && !inat_accept_vex(insn->attr)) {
>
+ /* Bad insn */
>
+ insn->attr = 0;
>
+ return -EINVAL;
>
+ }
>
}
>
}
>
>
if (insn->x86_64 && inat_is_force64(insn->attr))
>
insn->opnd_bytes = 8;
>
+
>
modrm->got = 1;
>
+ return 0;
>
>
err_out:
>
- return;
>
+ return -ENODATA;
>
}
>
>
>
@@ -326,11 +368,16 @@ void insn_get_modrm(struct insn *insn)
>
int insn_rip_relative(struct insn *insn)
>
{
>
struct insn_field *modrm = &insn->modrm;
>
+ int ret;
>
>
if (!insn->x86_64)
>
return 0;
>
- if (!modrm->got)
>
- insn_get_modrm(insn);
>
+
>
+ if (!modrm->got) {
>
+ ret = insn_get_modrm(insn);
>
+ if (ret)
>
+ return 0;
>
+ }
>
/*
>
* For rip-relative instructions, the mod field (top 2 bits)
>
* is zero and the r/m field (bottom 3 bits) is 0x5.
>
@@ -344,15 +391,25 @@ int insn_rip_relative(struct insn *insn)
>
*
>
* If necessary, first collects the instruction up to and including the
>
* ModRM byte.
>
+ *
>
+ * Returns:
>
+ * 0: if decoding succeeded
>
+ * < 0: otherwise.
>
*/
>
-void insn_get_sib(struct insn *insn)
>
+int insn_get_sib(struct insn *insn)
>
{
>
insn_byte_t modrm;
>
+ int ret;
>
>
if (insn->sib.got)
>
- return;
>
- if (!insn->modrm.got)
>
- insn_get_modrm(insn);
>
+ return 0;
>
+
>
+ if (!insn->modrm.got) {
>
+ ret = insn_get_modrm(insn);
>
+ if (ret)
>
+ return ret;
>
+ }
>
+
>
if (insn->modrm.nbytes) {
>
modrm = (insn_byte_t)insn->modrm.value;
>
if (insn->addr_bytes != 2 &&
>
@@ -363,8 +420,10 @@ void insn_get_sib(struct insn *insn)
>
}
>
insn->sib.got = 1;
>
>
+ return 0;
>
+
>
err_out:
>
- return;
>
+ return -ENODATA;
>
}
>
>
>
@@ -375,15 +434,25 @@ void insn_get_sib(struct insn *insn)
>
* If necessary, first collects the instruction up to and including the
>
* SIB byte.
>
* Displacement value is sign-expanded.
>
+ *
>
+ * * Returns:
>
+ * 0: if decoding succeeded
>
+ * < 0: otherwise.
>
*/
>
-void insn_get_displacement(struct insn *insn)
>
+int insn_get_displacement(struct insn *insn)
>
{
>
insn_byte_t mod, rm, base;
>
+ int ret;
>
>
if (insn->displacement.got)
>
- return;
>
- if (!insn->sib.got)
>
- insn_get_sib(insn);
>
+ return 0;
>
+
>
+ if (!insn->sib.got) {
>
+ ret = insn_get_sib(insn);
>
+ if (ret)
>
+ return ret;
>
+ }
>
+
>
if (insn->modrm.nbytes) {
>
/*
>
* Interpreting the modrm byte:
>
@@ -426,9 +495,10 @@ void insn_get_displacement(struct insn *insn)
>
}
>
out:
>
insn->displacement.got = 1;
>
+ return 0;
>
>
err_out:
>
- return;
>
+ return -ENODATA;
>
}
>
>
/* Decode moffset16/32/64. Return 0 if failed */
>
@@ -539,20 +609,30 @@ static int __get_immptr(struct insn *insn)
>
}
>
>
/**
>
- * insn_get_immediate() - Get the immediates of instruction
>
+ * insn_get_immediate() - Get the immediate in an instruction
>
* @insn: &struct insn containing instruction
>
*
>
* If necessary, first collects the instruction up to and including the
>
* displacement bytes.
>
* Basically, most of immediates are sign-expanded. Unsigned-value can be
>
- * get by bit masking with ((1 << (nbytes * 8)) - 1)
>
+ * computed by bit masking with ((1 << (nbytes * 8)) - 1)
>
+ *
>
+ * Returns:
>
+ * 0: on success
>
+ * < 0: on error
>
*/
>
-void insn_get_immediate(struct insn *insn)
>
+int insn_get_immediate(struct insn *insn)
>
{
>
+ int ret;
>
+
>
if (insn->immediate.got)
>
- return;
>
- if (!insn->displacement.got)
>
- insn_get_displacement(insn);
>
+ return 0;
>
+
>
+ if (!insn->displacement.got) {
>
+ ret = insn_get_displacement(insn);
>
+ if (ret)
>
+ return ret;
>
+ }
>
>
if (inat_has_moffset(insn->attr)) {
>
if (!__get_moffset(insn))
>
@@ -605,9 +685,10 @@ void insn_get_immediate(struct insn *insn)
>
}
>
done:
>
insn->immediate.got = 1;
>
+ return 0;
>
>
err_out:
>
- return;
>
+ return -ENODATA;
>
}
>
>
/**
>
@@ -616,13 +697,58 @@ void insn_get_immediate(struct insn *insn)
>
*
>
* If necessary, first collects the instruction up to and including the
>
* immediates bytes.
>
- */
>
-void insn_get_length(struct insn *insn)
>
+ *
>
+ * Returns:
>
+ * - 0 on success
>
+ * - < 0 on error
>
+*/
>
+int insn_get_length(struct insn *insn)
>
{
>
+ int ret;
>
+
>
if (insn->length)
>
- return;
>
- if (!insn->immediate.got)
>
- insn_get_immediate(insn);
>
+ return 0;
>
+
>
+ if (!insn->immediate.got) {
>
+ ret = insn_get_immediate(insn);
>
+ if (ret)
>
+ return ret;
>
+ }
>
+
>
insn->length = (unsigned char)((unsigned long)insn->next_byte
>
- (unsigned long)insn->kaddr);
>
+
>
+ return 0;
>
+}
>
+
>
+/**
>
+ * insn_decode() - Decode an x86 instruction
>
+ * @insn: &struct insn to be initialized
>
+ * @kaddr: address (in kernel memory) of instruction (or copy thereof)
>
+ * @buf_len: length of the insn buffer at @kaddr
>
+ * @m: insn mode, see enum insn_mode
>
+ *
>
+ * Returns:
>
+ * 0: if decoding succeeded
>
+ * < 0: otherwise.
>
+ */
>
+int insn_decode(struct insn *insn, const void *kaddr, int buf_len, enum insn_mode m)
>
+{
>
+ int ret;
>
+
>
+#define INSN_MODE_KERN (enum insn_mode)-1 /* __ignore_sync_check__ mode is only valid in the kernel */
>
+
>
+ if (m == INSN_MODE_KERN)
>
+ insn_init(insn, kaddr, buf_len, IS_ENABLED(CONFIG_X86_64));
>
+ else
>
+ insn_init(insn, kaddr, buf_len, m == INSN_MODE_64);
>
+
>
+ ret = insn_get_length(insn);
>
+ if (ret)
>
+ return ret;
>
+
>
+ if (insn_complete(insn))
>
+ return 0;
>
+
>
+ return -EINVAL;
>
}
>
diff --git a/tools/include/linux/kconfig.h b/tools/include/linux/kconfig.h
>
new file mode 100644
>
index 000000000000..1555a0c4f345
>
--- /dev/null
>
+++ b/tools/include/linux/kconfig.h
>
@@ -0,0 +1,73 @@
>
+/* SPDX-License-Identifier: GPL-2.0 */
>
+#ifndef _TOOLS_LINUX_KCONFIG_H
>
+#define _TOOLS_LINUX_KCONFIG_H
>
+
>
+/* CONFIG_CC_VERSION_TEXT (Do not delete this comment. See help in Kconfig) */
>
+
>
+#ifdef CONFIG_CPU_BIG_ENDIAN
>
+#define __BIG_ENDIAN 4321
>
+#else
>
+#define __LITTLE_ENDIAN 1234
>
+#endif
>
+
>
+#define __ARG_PLACEHOLDER_1 0,
>
+#define __take_second_arg(__ignored, val, ...) val
>
+
>
+/*
>
+ * The use of "&&" / "||" is limited in certain expressions.
>
+ * The following enable to calculate "and" / "or" with macro expansion only.
>
+ */
>
+#define __and(x, y) ___and(x, y)
>
+#define ___and(x, y) ____and(__ARG_PLACEHOLDER_##x, y)
>
+#define ____and(arg1_or_junk, y) __take_second_arg(arg1_or_junk y, 0)
>
+
>
+#define __or(x, y) ___or(x, y)
>
+#define ___or(x, y) ____or(__ARG_PLACEHOLDER_##x, y)
>
+#define ____or(arg1_or_junk, y) __take_second_arg(arg1_or_junk 1, y)
>
+
>
+/*
>
+ * Helper macros to use CONFIG_ options in C/CPP expressions. Note that
>
+ * these only work with boolean and tristate options.
>
+ */
>
+
>
+/*
>
+ * Getting something that works in C and CPP for an arg that may or may
>
+ * not be defined is tricky. Here, if we have "#define CONFIG_BOOGER 1"
>
+ * we match on the placeholder define, insert the "0," for arg1 and generate
>
+ * the triplet (0, 1, 0). Then the last step cherry picks the 2nd arg (a one).
>
+ * When CONFIG_BOOGER is not defined, we generate a (... 1, 0) pair, and when
>
+ * the last step cherry picks the 2nd arg, we get a zero.
>
+ */
>
+#define __is_defined(x) ___is_defined(x)
>
+#define ___is_defined(val) ____is_defined(__ARG_PLACEHOLDER_##val)
>
+#define ____is_defined(arg1_or_junk) __take_second_arg(arg1_or_junk 1, 0)
>
+
>
+/*
>
+ * IS_BUILTIN(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y', 0
>
+ * otherwise. For boolean options, this is equivalent to
>
+ * IS_ENABLED(CONFIG_FOO).
>
+ */
>
+#define IS_BUILTIN(option) __is_defined(option)
>
+
>
+/*
>
+ * IS_MODULE(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'm', 0
>
+ * otherwise.
>
+ */
>
+#define IS_MODULE(option) __is_defined(option##_MODULE)
>
+
>
+/*
>
+ * IS_REACHABLE(CONFIG_FOO) evaluates to 1 if the currently compiled
>
+ * code can call a function defined in code compiled based on CONFIG_FOO.
>
+ * This is similar to IS_ENABLED(), but returns false when invoked from
>
+ * built-in code when CONFIG_FOO is set to 'm'.
>
+ */
>
+#define IS_REACHABLE(option) __or(IS_BUILTIN(option), \
>
+ __and(IS_MODULE(option), __is_defined(MODULE)))
>
+
>
+/*
>
+ * IS_ENABLED(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y' or 'm',
>
+ * 0 otherwise.
>
+ */
>
+#define IS_ENABLED(option) __or(IS_BUILTIN(option), IS_MODULE(option))
>
+
>
+#endif /* _TOOLS_LINUX_KCONFIG_H */
>
--
>
2.29.2
>
>
--
>
Regards/Gruss,
>
Boris.
>
>
https://people.kernel.org/tglx/notes-about-netiquette
--
Masami Hiramatsu <mhiramat@xxxxxxxxxx>