2023-05-30 17:25:02

by Josh Poimboeuf

[permalink] [raw]
Subject: [PATCH 17/22] objtool: Get rid of reloc->jump_table_start

Rework the jump table logic slightly so 'jump_table_start' is no longer
needed.

With allyesconfig + CONFIG_DEBUG_INFO:

- Before: peak heap memory consumption: 40.37G
- After: peak heap memory consumption: 38.64G

Signed-off-by: Josh Poimboeuf <[email protected]>
---
tools/objtool/check.c | 35 +++++++++++++++++++----------
tools/objtool/include/objtool/elf.h | 1 -
2 files changed, 23 insertions(+), 13 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 12a9e6fb3fe7..3fe6b3657e22 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1988,13 +1988,14 @@ static int add_special_section_alts(struct objtool_file *file)
}

static int add_jump_table(struct objtool_file *file, struct instruction *insn,
- struct reloc *table)
+ struct reloc *next_table)
{
- struct reloc *reloc = table;
- struct instruction *dest_insn;
- struct alternative *alt;
struct symbol *pfunc = insn_func(insn)->pfunc;
+ struct reloc *table = insn_jump_table(insn);
+ struct instruction *dest_insn;
unsigned int prev_offset = 0;
+ struct reloc *reloc = table;
+ struct alternative *alt;

/*
* Each @reloc is a switch table relocation which points to the target
@@ -2003,7 +2004,7 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn,
for_each_reloc_from(table->sec, reloc) {

/* Check for the end of the table: */
- if (reloc != table && reloc->jump_table_start)
+ if (reloc != table && reloc == next_table)
break;

/* Make sure the table entries are consecutive: */
@@ -2118,29 +2119,39 @@ static void mark_func_jump_tables(struct objtool_file *file,
continue;

reloc = find_jump_table(file, func, insn);
- if (reloc) {
- reloc->jump_table_start = true;
+ if (reloc)
insn->_jump_table = reloc;
- }
}
}

static int add_func_jump_tables(struct objtool_file *file,
struct symbol *func)
{
- struct instruction *insn;
- int ret;
+ struct instruction *insn, *insn_t1 = NULL, *insn_t2;
+ int ret = 0;

func_for_each_insn(file, func, insn) {
if (!insn_jump_table(insn))
continue;

- ret = add_jump_table(file, insn, insn_jump_table(insn));
+ if (!insn_t1) {
+ insn_t1 = insn;
+ continue;
+ }
+
+ insn_t2 = insn;
+
+ ret = add_jump_table(file, insn_t1, insn_jump_table(insn_t2));
if (ret)
return ret;
+
+ insn_t1 = insn_t2;
}

- return 0;
+ if (insn_t1)
+ ret = add_jump_table(file, insn_t1, NULL);
+
+ return ret;
}

/*
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index be08b32a93ee..60686f746c9e 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -75,7 +75,6 @@ struct reloc {
struct section *sec;
struct symbol *sym;
struct list_head sym_reloc_entry;
- bool jump_table_start;
};

struct elf {
--
2.40.1



Subject: [tip: objtool/core] objtool: Get rid of reloc->jump_table_start

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

Commit-ID: be2f0b1e12644c956a347d7fde93c2ffe9cdb1af
Gitweb: https://git.kernel.org/tip/be2f0b1e12644c956a347d7fde93c2ffe9cdb1af
Author: Josh Poimboeuf <[email protected]>
AuthorDate: Tue, 30 May 2023 10:21:09 -07:00
Committer: Josh Poimboeuf <[email protected]>
CommitterDate: Wed, 07 Jun 2023 10:03:24 -07:00

objtool: Get rid of reloc->jump_table_start

Rework the jump table logic slightly so 'jump_table_start' is no longer
needed.

With allyesconfig + CONFIG_DEBUG_INFO:

- Before: peak heap memory consumption: 40.37G
- After: peak heap memory consumption: 38.64G

Link: https://lore.kernel.org/r/e1602ed8a6171ada3cfac0bd8449892ec82bd188.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <[email protected]>
---
tools/objtool/check.c | 35 ++++++++++++++++++----------
tools/objtool/include/objtool/elf.h | 1 +-
2 files changed, 23 insertions(+), 13 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 745487d..7fb6467 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1989,13 +1989,14 @@ out:
}

static int add_jump_table(struct objtool_file *file, struct instruction *insn,
- struct reloc *table)
+ struct reloc *next_table)
{
- struct reloc *reloc = table;
- struct instruction *dest_insn;
- struct alternative *alt;
struct symbol *pfunc = insn_func(insn)->pfunc;
+ struct reloc *table = insn_jump_table(insn);
+ struct instruction *dest_insn;
unsigned int prev_offset = 0;
+ struct reloc *reloc = table;
+ struct alternative *alt;

/*
* Each @reloc is a switch table relocation which points to the target
@@ -2004,7 +2005,7 @@ static int add_jump_table(struct objtool_file *file, struct instruction *insn,
for_each_reloc_from(table->sec, reloc) {

/* Check for the end of the table: */
- if (reloc != table && reloc->jump_table_start)
+ if (reloc != table && reloc == next_table)
break;

/* Make sure the table entries are consecutive: */
@@ -2119,29 +2120,39 @@ static void mark_func_jump_tables(struct objtool_file *file,
continue;

reloc = find_jump_table(file, func, insn);
- if (reloc) {
- reloc->jump_table_start = true;
+ if (reloc)
insn->_jump_table = reloc;
- }
}
}

static int add_func_jump_tables(struct objtool_file *file,
struct symbol *func)
{
- struct instruction *insn;
- int ret;
+ struct instruction *insn, *insn_t1 = NULL, *insn_t2;
+ int ret = 0;

func_for_each_insn(file, func, insn) {
if (!insn_jump_table(insn))
continue;

- ret = add_jump_table(file, insn, insn_jump_table(insn));
+ if (!insn_t1) {
+ insn_t1 = insn;
+ continue;
+ }
+
+ insn_t2 = insn;
+
+ ret = add_jump_table(file, insn_t1, insn_jump_table(insn_t2));
if (ret)
return ret;
+
+ insn_t1 = insn_t2;
}

- return 0;
+ if (insn_t1)
+ ret = add_jump_table(file, insn_t1, NULL);
+
+ return ret;
}

/*
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index be08b32..60686f7 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -75,7 +75,6 @@ struct reloc {
struct section *sec;
struct symbol *sym;
struct list_head sym_reloc_entry;
- bool jump_table_start;
};

struct elf {