Re: [PATCH v3 04/21] x86/insn: Add an insn_decode() API
From: Ian Rogers
Date: Tue Mar 16 2021 - 21:16:03 EST
On Thu, Mar 4, 2021 at 9:56 AM Borislav Petkov <bp@xxxxxxxxx> wrote:
>
> From: Borislav Petkov <bp@xxxxxxx>
>
> 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.
>
> Signed-off-by: Borislav Petkov <bp@xxxxxxx>
> Acked-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> ---
> 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 93f84600ac2c..de9fe760c1e7 100644
> --- a/arch/x86/include/asm/insn.h
> +++ b/arch/x86/include/asm/insn.h
> @@ -132,13 +132,23 @@ 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 ed1e0335aa14..bb58004497f8 100644
> --- a/arch/x86/lib/insn.c
> +++ b/arch/x86/lib/insn.c
> @@ -14,6 +14,9 @@
> #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__ */
>
> #define leXX_to_cpu(t, r) \
> @@ -112,8 +115,12 @@ 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;
> @@ -121,7 +128,7 @@ void insn_get_prefixes(struct insn *insn)
> int i, nb;
>
> if (prefixes->got)
> - return;
> + return 0;
>
> insn_get_emulate_prefix(insn);
>
> @@ -231,8 +238,10 @@ void insn_get_prefixes(struct insn *insn)
>
> prefixes->got = 1;
>
> + return 0;
> +
> err_out:
> - return;
> + return -ENODATA;
> }
>
> /**
> @@ -244,16 +253,25 @@ 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);
> @@ -268,9 +286,13 @@ 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);
> @@ -281,13 +303,18 @@ 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;
> }
>
> /**
> @@ -297,15 +324,25 @@ 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);
> @@ -314,17 +351,22 @@ 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;
> }
>
>
> @@ -338,11 +380,16 @@ 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.
> @@ -356,15 +403,25 @@ 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->modrm.bytes[0];
> if (insn->addr_bytes != 2 &&
> @@ -375,8 +432,10 @@ void insn_get_sib(struct insn *insn)
> }
> insn->sib.got = 1;
>
> + return 0;
> +
> err_out:
> - return;
> + return -ENODATA;
> }
>
>
> @@ -387,15 +446,25 @@ 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:
> @@ -437,9 +506,10 @@ 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 */
> @@ -538,20 +608,30 @@ 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))
> @@ -598,9 +678,10 @@ void insn_get_immediate(struct insn *insn)
> }
> done:
> insn->immediate.got = 1;
> + return 0;
>
> err_out:
> - return;
> + return -ENODATA;
> }
>
> /**
> @@ -609,13 +690,58 @@ 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 7e1239aa7dd9..2fe19b1a8765 100644
> --- a/tools/arch/x86/include/asm/insn.h
> +++ b/tools/arch/x86/include/asm/insn.h
> @@ -132,13 +132,23 @@ 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 1174c43b3944..be2b057f91d4 100644
> --- a/tools/arch/x86/lib/insn.c
> +++ b/tools/arch/x86/lib/insn.c
> @@ -11,10 +11,13 @@
> #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__ */
Hi, this change is breaking non-x86 builds of perf for me in
tip.git/master. The reason being that non-x86 builds compile the
intel-pt-decoder, which includes this file, but don't have their
include paths set to find tools/arch/x86. I think we want to keep the
relative paths.
Thanks,
Ian
> -#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__ */
>
> #define leXX_to_cpu(t, r) \
> ({ \
> @@ -112,8 +115,12 @@ 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;
> @@ -121,7 +128,7 @@ void insn_get_prefixes(struct insn *insn)
> int i, nb;
>
> if (prefixes->got)
> - return;
> + return 0;
>
> insn_get_emulate_prefix(insn);
>
> @@ -231,8 +238,10 @@ void insn_get_prefixes(struct insn *insn)
>
> prefixes->got = 1;
>
> + return 0;
> +
> err_out:
> - return;
> + return -ENODATA;
> }
>
> /**
> @@ -244,16 +253,25 @@ 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);
> @@ -268,9 +286,13 @@ 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);
> @@ -281,13 +303,18 @@ 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;
> }
>
> /**
> @@ -297,15 +324,25 @@ 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);
> @@ -314,17 +351,22 @@ 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;
> }
>
>
> @@ -338,11 +380,16 @@ 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.
> @@ -356,15 +403,25 @@ 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->modrm.bytes[0];
> if (insn->addr_bytes != 2 &&
> @@ -375,8 +432,10 @@ void insn_get_sib(struct insn *insn)
> }
> insn->sib.got = 1;
>
> + return 0;
> +
> err_out:
> - return;
> + return -ENODATA;
> }
>
>
> @@ -387,15 +446,25 @@ 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:
> @@ -437,9 +506,10 @@ 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 */
> @@ -538,20 +608,30 @@ 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))
> @@ -598,9 +678,10 @@ void insn_get_immediate(struct insn *insn)
> }
> done:
> insn->immediate.got = 1;
> + return 0;
>
> err_out:
> - return;
> + return -ENODATA;
> }
>
> /**
> @@ -609,13 +690,58 @@ 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
>