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-rw-r--r--arch/x86/lib/insn.c216
1 files changed, 171 insertions, 45 deletions
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 @@ vex_end:
prefixes->got = 1;
+ return 0;
+
err_out:
- return;
+ return -ENODATA;
}
/**
@@ -244,16 +253,25 @@ err_out:
* 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 @@ err_out:
* 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 @@ err_out:
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 @@ err_out:
* 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 @@ err_out:
}
/**
- * 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 @@ err_out:
*
* 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;
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-10-30 14:34:49 +0000