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Date: Wed, 08 Feb 2023 18:18:02 +0100
From: Peter Zijlstra <peterz@...radead.org>
To: x86@...nel.org, jpoimboe@...hat.com, linux@...ssschuh.net
Cc: linux-kernel@...r.kernel.org, peterz@...radead.org
Subject: [PATCH 06/10] objtool: Union instruction::{call_dest,jump_table}
The instruction call_dest and jump_table members can never be used at
the same time, their usage depends on type.
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) --- */
long unsigned int immediate; /* 64 8 */
unsigned int len; /* 72 4 */
u8 type; /* 76 1 */
/* Bitfield combined with previous fields */
u16 dead_end:1; /* 76: 8 2 */
u16 ignore:1; /* 76: 9 2 */
u16 ignore_alts:1; /* 76:10 2 */
u16 hint:1; /* 76:11 2 */
u16 save:1; /* 76:12 2 */
u16 restore:1; /* 76:13 2 */
u16 retpoline_safe:1; /* 76:14 2 */
u16 noendbr:1; /* 76:15 2 */
u16 entry:1; /* 78: 0 2 */
u16 visited:4; /* 78: 1 2 */
u16 no_reloc:1; /* 78: 5 2 */
/* XXX 2 bits hole, try to pack */
/* Bitfield combined with next fields */
s8 instr; /* 79 1 */
struct alt_group * alt_group; /* 80 8 */
- struct symbol * call_dest; /* 88 8 */
- struct instruction * jump_dest; /* 96 8 */
- struct instruction * first_jump_src; /* 104 8 */
- struct reloc * jump_table; /* 112 8 */
- struct alternative * alts; /* 120 8 */
+ struct instruction * jump_dest; /* 88 8 */
+ struct instruction * first_jump_src; /* 96 8 */
+ union {
+ struct symbol * _call_dest; /* 104 8 */
+ struct reloc * _jump_table; /* 104 8 */
+ }; /* 104 8 */
+ struct alternative * alts; /* 112 8 */
+ struct symbol * sym; /* 120 8 */
/* --- cacheline 2 boundary (128 bytes) --- */
- struct symbol * sym; /* 128 8 */
- struct stack_op * stack_ops; /* 136 8 */
- struct cfi_state * cfi; /* 144 8 */
+ struct stack_op * stack_ops; /* 128 8 */
+ struct cfi_state * cfi; /* 136 8 */
- /* size: 152, cachelines: 3, members: 29 */
- /* sum members: 150 */
+ /* size: 144, cachelines: 3, members: 28 */
+ /* sum members: 142 */
/* sum bitfield members: 14 bits, bit holes: 1, sum bit holes: 2 bits */
- /* last cacheline: 24 bytes */
+ /* last cacheline: 16 bytes */
};
pre: 5:39.35 real, 215.58 user, 123.69 sys, 23448736 mem
post: 5:38.18 real, 213.25 user, 124.90 sys, 23449040 mem
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
tools/objtool/check.c | 73 +++++++++++++++++++++-------------
tools/objtool/include/objtool/check.h | 6 +-
2 files changed, 50 insertions(+), 29 deletions(-)
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -114,16 +114,34 @@ static struct instruction *prev_insn_sam
for (insn = next_insn_same_sec(file, insn); insn; \
insn = next_insn_same_sec(file, insn))
+static inline struct symbol *insn_call_dest(struct instruction *insn)
+{
+ if (insn->type == INSN_JUMP_DYNAMIC ||
+ insn->type == INSN_CALL_DYNAMIC)
+ return NULL;
+
+ return insn->_call_dest;
+}
+
+static inline struct reloc *insn_jump_table(struct instruction *insn)
+{
+ if (insn->type == INSN_JUMP_DYNAMIC ||
+ insn->type == INSN_CALL_DYNAMIC)
+ return insn->_jump_table;
+
+ return NULL;
+}
+
static bool is_jump_table_jump(struct instruction *insn)
{
struct alt_group *alt_group = insn->alt_group;
- if (insn->jump_table)
+ if (insn_jump_table(insn))
return true;
/* Retpoline alternative for a jump table? */
return alt_group && alt_group->orig_group &&
- alt_group->orig_group->first_insn->jump_table;
+ insn_jump_table(alt_group->orig_group->first_insn);
}
static bool is_sibling_call(struct instruction *insn)
@@ -137,8 +155,8 @@ static bool is_sibling_call(struct instr
return !is_jump_table_jump(insn);
}
- /* add_jump_destinations() sets insn->call_dest for sibling calls. */
- return (is_static_jump(insn) && insn->call_dest);
+ /* add_jump_destinations() sets insn_call_dest(insn) for sibling calls. */
+ return (is_static_jump(insn) && insn_call_dest(insn));
}
/*
@@ -273,8 +291,8 @@ static void init_insn_state(struct objto
/*
* We need the full vmlinux for noinstr validation, otherwise we can
- * not correctly determine insn->call_dest->sec (external symbols do
- * not have a section).
+ * not correctly determine insn_call_dest(insn)->sec (external symbols
+ * do not have a section).
*/
if (opts.link && opts.noinstr && sec)
state->noinstr = sec->noinstr;
@@ -677,7 +695,7 @@ static int create_static_call_sections(s
return -1;
/* find key symbol */
- key_name = strdup(insn->call_dest->name);
+ key_name = strdup(insn_call_dest(insn)->name);
if (!key_name) {
perror("strdup");
return -1;
@@ -708,7 +726,7 @@ static int create_static_call_sections(s
* trampoline address. This is fixed up in
* static_call_add_module().
*/
- key_sym = insn->call_dest;
+ key_sym = insn_call_dest(insn);
}
free(key_name);
@@ -1342,7 +1360,7 @@ static void annotate_call_site(struct ob
struct instruction *insn, bool sibling)
{
struct reloc *reloc = insn_reloc(file, insn);
- struct symbol *sym = insn->call_dest;
+ struct symbol *sym = insn_call_dest(insn);
if (!sym)
sym = reloc->sym;
@@ -1427,7 +1445,7 @@ static void annotate_call_site(struct ob
static void add_call_dest(struct objtool_file *file, struct instruction *insn,
struct symbol *dest, bool sibling)
{
- insn->call_dest = dest;
+ insn->_call_dest = dest;
if (!dest)
return;
@@ -1685,12 +1703,12 @@ static int add_call_destinations(struct
if (insn->ignore)
continue;
- if (!insn->call_dest) {
+ if (!insn_call_dest(insn)) {
WARN_FUNC("unannotated intra-function call", insn->sec, insn->offset);
return -1;
}
- if (insn_func(insn) && insn->call_dest->type != STT_FUNC) {
+ if (insn_func(insn) && insn_call_dest(insn)->type != STT_FUNC) {
WARN_FUNC("unsupported call to non-function",
insn->sec, insn->offset);
return -1;
@@ -2127,7 +2145,7 @@ static void mark_func_jump_tables(struct
reloc = find_jump_table(file, func, insn);
if (reloc) {
reloc->jump_table_start = true;
- insn->jump_table = reloc;
+ insn->_jump_table = reloc;
}
}
}
@@ -2139,10 +2157,10 @@ static int add_func_jump_tables(struct o
int ret;
func_for_each_insn(file, func, insn) {
- if (!insn->jump_table)
+ if (!insn_jump_table(insn))
continue;
- ret = add_jump_table(file, insn, insn->jump_table);
+ ret = add_jump_table(file, insn, insn_jump_table(insn));
if (ret)
return ret;
}
@@ -2614,8 +2632,8 @@ static int decode_sections(struct objtoo
static bool is_fentry_call(struct instruction *insn)
{
if (insn->type == INSN_CALL &&
- insn->call_dest &&
- insn->call_dest->fentry)
+ insn_call_dest(insn) &&
+ insn_call_dest(insn)->fentry)
return true;
return false;
@@ -3322,8 +3340,8 @@ static inline const char *call_dest_name
struct reloc *rel;
int idx;
- if (insn->call_dest)
- return insn->call_dest->name;
+ if (insn_call_dest(insn))
+ return insn_call_dest(insn)->name;
rel = insn_reloc(NULL, insn);
if (rel && !strcmp(rel->sym->name, "pv_ops")) {
@@ -3405,13 +3423,13 @@ static int validate_call(struct objtool_
struct insn_state *state)
{
if (state->noinstr && state->instr <= 0 &&
- !noinstr_call_dest(file, insn, insn->call_dest)) {
+ !noinstr_call_dest(file, insn, insn_call_dest(insn))) {
WARN_FUNC("call to %s() leaves .noinstr.text section",
insn->sec, insn->offset, call_dest_name(insn));
return 1;
}
- if (state->uaccess && !func_uaccess_safe(insn->call_dest)) {
+ if (state->uaccess && !func_uaccess_safe(insn_call_dest(insn))) {
WARN_FUNC("call to %s() with UACCESS enabled",
insn->sec, insn->offset, call_dest_name(insn));
return 1;
@@ -3849,11 +3867,11 @@ static int validate_entry(struct objtool
/* fallthrough */
case INSN_CALL:
- dest = find_insn(file, insn->call_dest->sec,
- insn->call_dest->offset);
+ dest = find_insn(file, insn_call_dest(insn)->sec,
+ insn_call_dest(insn)->offset);
if (!dest) {
WARN("Unresolved function after linking!?: %s",
- insn->call_dest->name);
+ insn_call_dest(insn)->name);
return -1;
}
@@ -3954,13 +3972,13 @@ static int validate_retpoline(struct obj
static bool is_kasan_insn(struct instruction *insn)
{
return (insn->type == INSN_CALL &&
- !strcmp(insn->call_dest->name, "__asan_handle_no_return"));
+ !strcmp(insn_call_dest(insn)->name, "__asan_handle_no_return"));
}
static bool is_ubsan_insn(struct instruction *insn)
{
return (insn->type == INSN_CALL &&
- !strcmp(insn->call_dest->name,
+ !strcmp(insn_call_dest(insn)->name,
"__ubsan_handle_builtin_unreachable"));
}
@@ -4038,7 +4056,8 @@ static bool ignore_unreachable_insn(stru
* It may also insert a UD2 after calling a __noreturn function.
*/
prev_insn = list_prev_entry(insn, list);
- if ((prev_insn->dead_end || dead_end_function(file, prev_insn->call_dest)) &&
+ if ((prev_insn->dead_end ||
+ dead_end_function(file, insn_call_dest(prev_insn))) &&
(insn->type == INSN_BUG ||
(insn->type == INSN_JUMP_UNCONDITIONAL &&
insn->jump_dest && insn->jump_dest->type == INSN_BUG)))
--- a/tools/objtool/include/objtool/check.h
+++ b/tools/objtool/include/objtool/check.h
@@ -62,10 +62,12 @@ struct instruction {
s8 instr;
struct alt_group *alt_group;
- struct symbol *call_dest;
struct instruction *jump_dest;
struct instruction *first_jump_src;
- struct reloc *jump_table;
+ union {
+ struct symbol *_call_dest;
+ struct reloc *_jump_table;
+ };
struct alternative *alts;
struct symbol *sym;
struct stack_op *stack_ops;
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