github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-10-26 00:56:03 +01:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

x86/insn: Simplify for_each_insn_prefix()

Browse Source 
Use the new-found freedom of allowing variable declarions inside
for() to simplify the for_each_insn_prefix() iterator to no longer
need an external temporary.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
This commit is contained in:
Peter Zijlstra 2025-09-25 10:19:05 +02:00
parent 8a5c6cbfe4
commit 45e1dccc06
6 changed files with 13 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
arch/x86/boot/compressed/sev-handle-vc.c
View File

@ -29,11 +29,10 @@
bool insn_has_rep_prefix(struct insn *insn) bool insn_has_rep_prefix(struct insn *insn)
{ {
insn_byte_t p; insn_byte_t p;
int i;
insn_get_prefixes(insn); insn_get_prefixes(insn);
for_each_insn_prefix(insn, i, p) { for_each_insn_prefix(insn, p) {
if (p == 0xf2 || p == 0xf3) if (p == 0xf2 || p == 0xf3)
return true; return true;
} }

5
arch/x86/include/asm/insn.h
View File

@ -312,7 +312,6 @@ static inline int insn_offset_immediate(struct insn *insn)
/** /**
* for_each_insn_prefix() -- Iterate prefixes in the instruction * for_each_insn_prefix() -- Iterate prefixes in the instruction
* @insn: Pointer to struct insn. * @insn: Pointer to struct insn.
* @idx: Index storage.
* @prefix: Prefix byte. * @prefix: Prefix byte.
* *
* Iterate prefix bytes of given @insn. Each prefix byte is stored in @prefix * Iterate prefix bytes of given @insn. Each prefix byte is stored in @prefix
@ -321,8 +320,8 @@ static inline int insn_offset_immediate(struct insn *insn)
* Since prefixes.nbytes can be bigger than 4 if some prefixes * Since prefixes.nbytes can be bigger than 4 if some prefixes
* are repeated, it cannot be used for looping over the prefixes. * are repeated, it cannot be used for looping over the prefixes.
*/ */
#define for_each_insn_prefix(insn, idx, prefix) \ #define for_each_insn_prefix(insn, prefix) \
for (idx = 0; idx < ARRAY_SIZE(insn->prefixes.bytes) && (prefix = insn->prefixes.bytes[idx]) != 0; idx++) for (int idx = 0; idx < ARRAY_SIZE(insn->prefixes.bytes) && (prefix = insn->prefixes.bytes[idx]) != 0; idx++)
#define POP_SS_OPCODE 0x1f #define POP_SS_OPCODE 0x1f
#define MOV_SREG_OPCODE 0x8e #define MOV_SREG_OPCODE 0x8e

3
arch/x86/kernel/kprobes/core.c
View File

@ -141,7 +141,6 @@ bool can_boost(struct insn *insn, void *addr)
{ {
kprobe_opcode_t opcode; kprobe_opcode_t opcode;
insn_byte_t prefix; insn_byte_t prefix;
int i;
if (search_exception_tables((unsigned long)addr)) if (search_exception_tables((unsigned long)addr))
return false; /* Page fault may occur on this address. */ return false; /* Page fault may occur on this address. */
@ -154,7 +153,7 @@ bool can_boost(struct insn *insn, void *addr)
if (insn->opcode.nbytes != 1) if (insn->opcode.nbytes != 1)
return false; return false;
for_each_insn_prefix(insn, i, prefix) { for_each_insn_prefix(insn, prefix) {
insn_attr_t attr; insn_attr_t attr;
attr = inat_get_opcode_attribute(prefix); attr = inat_get_opcode_attribute(prefix);

6
arch/x86/kernel/uprobes.c
View File

@ -259,9 +259,8 @@ static volatile u32 good_2byte_insns[256 / 32] = {
static bool is_prefix_bad(struct insn *insn) static bool is_prefix_bad(struct insn *insn)
{ {
insn_byte_t p; insn_byte_t p;
int i;
for_each_insn_prefix(insn, i, p) { for_each_insn_prefix(insn, p) {
insn_attr_t attr; insn_attr_t attr;
attr = inat_get_opcode_attribute(p); attr = inat_get_opcode_attribute(p);
@ -1404,7 +1403,6 @@ static int branch_setup_xol_ops(struct arch_uprobe *auprobe, struct insn *insn)
{ {
u8 opc1 = OPCODE1(insn); u8 opc1 = OPCODE1(insn);
insn_byte_t p; insn_byte_t p;
int i;
if (insn_is_nop(insn)) if (insn_is_nop(insn))
goto setup; goto setup;
@ -1437,7 +1435,7 @@ static int branch_setup_xol_ops(struct arch_uprobe *auprobe, struct insn *insn)
* Intel and AMD behavior differ in 64-bit mode: Intel ignores 66 prefix. * Intel and AMD behavior differ in 64-bit mode: Intel ignores 66 prefix.
* No one uses these insns, reject any branch insns with such prefix. * No one uses these insns, reject any branch insns with such prefix.
*/ */
for_each_insn_prefix(insn, i, p) { for_each_insn_prefix(insn, p) {
if (p == 0x66) if (p == 0x66)
return -ENOTSUPP; return -ENOTSUPP;
} }

12
arch/x86/lib/insn-eval.c
View File

@ -63,11 +63,10 @@ static bool is_string_insn(struct insn *insn)
bool insn_has_rep_prefix(struct insn *insn) bool insn_has_rep_prefix(struct insn *insn)
{ {
insn_byte_t p; insn_byte_t p;
int i;
insn_get_prefixes(insn); insn_get_prefixes(insn);
for_each_insn_prefix(insn, i, p) { for_each_insn_prefix(insn, p) {
if (p == 0xf2 || p == 0xf3) if (p == 0xf2 || p == 0xf3)
return true; return true;
} }
@ -92,13 +91,13 @@ bool insn_has_rep_prefix(struct insn *insn)
static int get_seg_reg_override_idx(struct insn *insn) static int get_seg_reg_override_idx(struct insn *insn)
{ {
int idx = INAT_SEG_REG_DEFAULT; int idx = INAT_SEG_REG_DEFAULT;
int num_overrides = 0, i; int num_overrides = 0;
insn_byte_t p; insn_byte_t p;
insn_get_prefixes(insn); insn_get_prefixes(insn);
/* Look for any segment override prefixes. */ /* Look for any segment override prefixes. */
for_each_insn_prefix(insn, i, p) { for_each_insn_prefix(insn, p) {
insn_attr_t attr; insn_attr_t attr;
attr = inat_get_opcode_attribute(p); attr = inat_get_opcode_attribute(p);
@ -1701,7 +1700,6 @@ bool insn_is_nop(struct insn *insn)
u8 sib = 0, sib_scale, sib_index, sib_base; u8 sib = 0, sib_scale, sib_index, sib_base;
u8 nrex, rex; u8 nrex, rex;
u8 p, rep = 0; u8 p, rep = 0;
int i;
if ((nrex = insn->rex_prefix.nbytes)) { if ((nrex = insn->rex_prefix.nbytes)) {
rex = insn->rex_prefix.bytes[nrex-1]; rex = insn->rex_prefix.bytes[nrex-1];
@ -1741,7 +1739,7 @@ bool insn_is_nop(struct insn *insn)
modrm_rm = sib_base; modrm_rm = sib_base;
} }
for_each_insn_prefix(insn, i, p) { for_each_insn_prefix(insn, p) {
if (p == 0xf3) /* REPE */ if (p == 0xf3) /* REPE */
rep = 1; rep = 1;
} }
@ -1789,7 +1787,7 @@ bool insn_is_nop(struct insn *insn)
if (sib && (sib_scale != 0 || sib_index != 4)) /* (%reg, %eiz, 1) */ if (sib && (sib_scale != 0 || sib_index != 4)) /* (%reg, %eiz, 1) */
return false; return false;
for_each_insn_prefix(insn, i, p) { for_each_insn_prefix(insn, p) {
if (p != 0x3e) /* DS */ if (p != 0x3e) /* DS */
return false; return false;
} }

5
tools/arch/x86/include/asm/insn.h
View File

@ -312,7 +312,6 @@ static inline int insn_offset_immediate(struct insn *insn)
/** /**
* for_each_insn_prefix() -- Iterate prefixes in the instruction * for_each_insn_prefix() -- Iterate prefixes in the instruction
* @insn: Pointer to struct insn. * @insn: Pointer to struct insn.
* @idx: Index storage.
* @prefix: Prefix byte. * @prefix: Prefix byte.
* *
* Iterate prefix bytes of given @insn. Each prefix byte is stored in @prefix * Iterate prefix bytes of given @insn. Each prefix byte is stored in @prefix
@ -321,8 +320,8 @@ static inline int insn_offset_immediate(struct insn *insn)
* Since prefixes.nbytes can be bigger than 4 if some prefixes * Since prefixes.nbytes can be bigger than 4 if some prefixes
* are repeated, it cannot be used for looping over the prefixes. * are repeated, it cannot be used for looping over the prefixes.
*/ */
#define for_each_insn_prefix(insn, idx, prefix) \ #define for_each_insn_prefix(insn, prefix) \
for (idx = 0; idx < ARRAY_SIZE(insn->prefixes.bytes) && (prefix = insn->prefixes.bytes[idx]) != 0; idx++) for (int idx = 0; idx < ARRAY_SIZE(insn->prefixes.bytes) && (prefix = insn->prefixes.bytes[idx]) != 0; idx++)
#define POP_SS_OPCODE 0x1f #define POP_SS_OPCODE 0x1f
#define MOV_SREG_OPCODE 0x8e #define MOV_SREG_OPCODE 0x8e