[tip: objtool/core] objtool: Make instruction::stack_ops a single-linked list

From: tip-bot2 for Peter Zijlstra
Date: Thu Feb 23 2023 - 03:32:46 EST

The following commit has been merged into the objtool/core branch of tip:

Commit-ID: 3ee88df1b063962e39d7798ccc3b18fd10cea813
Gitweb: https://git.kernel.org/tip/3ee88df1b063962e39d7798ccc3b18fd10cea813
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Wed, 08 Feb 2023 18:17:58 +01:00
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Thu, 23 Feb 2023 09:20:59 +01:00

objtool: Make instruction::stack_ops a single-linked list

struct instruction {
struct list_head list; /* 0 16 */
struct hlist_node hash; /* 16 16 */
struct list_head call_node; /* 32 16 */
struct section * sec; /* 48 8 */
long unsigned int offset; /* 56 8 */
/* --- cacheline 1 boundary (64 bytes) --- */
unsigned int len; /* 64 4 */
enum insn_type type; /* 68 4 */
long unsigned int immediate; /* 72 8 */
u16 dead_end:1; /* 80: 0 2 */
u16 ignore:1; /* 80: 1 2 */
u16 ignore_alts:1; /* 80: 2 2 */
u16 hint:1; /* 80: 3 2 */
u16 save:1; /* 80: 4 2 */
u16 restore:1; /* 80: 5 2 */
u16 retpoline_safe:1; /* 80: 6 2 */
u16 noendbr:1; /* 80: 7 2 */
u16 entry:1; /* 80: 8 2 */

/* XXX 7 bits hole, try to pack */

s8 instr; /* 82 1 */
u8 visited; /* 83 1 */

/* XXX 4 bytes hole, try to pack */

struct alt_group * alt_group; /* 88 8 */
struct symbol * call_dest; /* 96 8 */
struct instruction * jump_dest; /* 104 8 */
struct instruction * first_jump_src; /* 112 8 */
struct reloc * jump_table; /* 120 8 */
/* --- cacheline 2 boundary (128 bytes) --- */
struct reloc * reloc; /* 128 8 */
struct list_head alts; /* 136 16 */
struct symbol * sym; /* 152 8 */
- struct list_head stack_ops; /* 160 16 */
- struct cfi_state * cfi; /* 176 8 */
+ struct stack_op * stack_ops; /* 160 8 */
+ struct cfi_state * cfi; /* 168 8 */

- /* size: 184, cachelines: 3, members: 29 */
- /* sum members: 178, holes: 1, sum holes: 4 */
+ /* size: 176, cachelines: 3, members: 29 */
+ /* sum members: 170, holes: 1, sum holes: 4 */
/* sum bitfield members: 9 bits, bit holes: 1, sum bit holes: 7 bits */
- /* last cacheline: 56 bytes */
+ /* last cacheline: 48 bytes */
};

pre: 5:58.22 real, 226.69 user, 131.22 sys, 26221520 mem
post: 5:58.50 real, 229.64 user, 128.65 sys, 26221520 mem

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Acked-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Tested-by: Nathan Chancellor <nathan@xxxxxxxxxx> # build only
Tested-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx> # compile and run
Link: https://lore.kernel.org/r/20230208172245.362196959@xxxxxxxxxxxxx
---
tools/objtool/arch/x86/decode.c | 4 ++--
tools/objtool/check.c | 11 +++++------
tools/objtool/include/objtool/arch.h | 2 +-
tools/objtool/include/objtool/check.h | 2 +-
4 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
index c5c4927..9ef024f 100644
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -105,7 +105,7 @@ bool arch_pc_relative_reloc(struct reloc *reloc)
#define ADD_OP(op) \
if (!(op = calloc(1, sizeof(*op)))) \
return -1; \
- else for (list_add_tail(&op->list, ops_list); op; op = NULL)
+ else for (*ops_list = op, ops_list = &op->next; op; op = NULL)

/*
* Helpers to decode ModRM/SIB:
@@ -148,7 +148,7 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
unsigned long offset, unsigned int maxlen,
struct instruction *insn)
{
- struct list_head *ops_list = &insn->stack_ops;
+ struct stack_op **ops_list = &insn->stack_ops;
const struct elf *elf = file->elf;
struct insn ins;
int x86_64, ret;
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index b3b423d..8109d74 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -398,7 +398,6 @@ static int decode_instructions(struct objtool_file *file)
}
memset(insn, 0, sizeof(*insn));
INIT_LIST_HEAD(&insn->alts);
- INIT_LIST_HEAD(&insn->stack_ops);
INIT_LIST_HEAD(&insn->call_node);

insn->sec = sec;
@@ -1331,12 +1330,13 @@ static struct reloc *insn_reloc(struct objtool_file *file, struct instruction *i

static void remove_insn_ops(struct instruction *insn)
{
- struct stack_op *op, *tmp;
+ struct stack_op *op, *next;

- list_for_each_entry_safe(op, tmp, &insn->stack_ops, list) {
- list_del(&op->list);
+ for (op = insn->stack_ops; op; op = next) {
+ next = op->next;
free(op);
}
+ insn->stack_ops = NULL;
}

static void annotate_call_site(struct objtool_file *file,
@@ -1781,7 +1781,6 @@ static int handle_group_alt(struct objtool_file *file,
}
memset(nop, 0, sizeof(*nop));
INIT_LIST_HEAD(&nop->alts);
- INIT_LIST_HEAD(&nop->stack_ops);

nop->sec = special_alt->new_sec;
nop->offset = special_alt->new_off + special_alt->new_len;
@@ -3226,7 +3225,7 @@ static int handle_insn_ops(struct instruction *insn,
{
struct stack_op *op;

- list_for_each_entry(op, &insn->stack_ops, list) {
+ for (op = insn->stack_ops; op; op = op->next) {

if (update_cfi_state(insn, next_insn, &state->cfi, op))
return 1;
diff --git a/tools/objtool/include/objtool/arch.h b/tools/objtool/include/objtool/arch.h
index 73149f8..2b6d2ce 100644
--- a/tools/objtool/include/objtool/arch.h
+++ b/tools/objtool/include/objtool/arch.h
@@ -62,9 +62,9 @@ struct op_src {
};

struct stack_op {
+ struct stack_op *next;
struct op_dest dest;
struct op_src src;
- struct list_head list;
};

struct instruction;
diff --git a/tools/objtool/include/objtool/check.h b/tools/objtool/include/objtool/check.h
index acd7fae..23e9819 100644
--- a/tools/objtool/include/objtool/check.h
+++ b/tools/objtool/include/objtool/check.h
@@ -68,7 +68,7 @@ struct instruction {
struct reloc *reloc;
struct list_head alts;
struct symbol *sym;
- struct list_head stack_ops;
+ struct stack_op *stack_ops;
struct cfi_state *cfi;
};