2023-05-30 17:23:14

by Josh Poimboeuf

Subject: [PATCH 02/22] objtool: Remove flags argument from elf_create_section()

Simplify the elf_create_section() interface a bit by removing the flags
argument. Most callers don't care about changing the section header
flags. If needed, they can be modified afterwards, just like any other
section header field.

Signed-off-by: Josh Poimboeuf <[email protected]>
---
tools/objtool/check.c | 17 ++++++++++-------
tools/objtool/elf.c | 10 +++++-----
tools/objtool/include/objtool/elf.h | 2 +-
tools/objtool/orc_gen.c | 4 ++--
4 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index a13c257f80dd..bc6771550423 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -676,11 +676,14 @@ static int create_static_call_sections(struct objtool_file *file)
list_for_each_entry(insn, &file->static_call_list, call_node)
idx++;

- sec = elf_create_section(file->elf, ".static_call_sites", SHF_WRITE,
+ sec = elf_create_section(file->elf, ".static_call_sites",
sizeof(struct static_call_site), idx);
if (!sec)
return -1;

+ /* Allow modules to set the low bits of static_call_site::key */
+ sec->sh.sh_flags |= SHF_WRITE;
+
idx = 0;
list_for_each_entry(insn, &file->static_call_list, call_node) {

@@ -762,7 +765,7 @@ static int create_retpoline_sites_sections(struct objtool_file *file)
if (!idx)
return 0;

- sec = elf_create_section(file->elf, ".retpoline_sites", 0,
+ sec = elf_create_section(file->elf, ".retpoline_sites",
sizeof(int), idx);
if (!sec) {
WARN("elf_create_section: .retpoline_sites");
@@ -808,7 +811,7 @@ static int create_return_sites_sections(struct objtool_file *file)
if (!idx)
return 0;

- sec = elf_create_section(file->elf, ".return_sites", 0,
+ sec = elf_create_section(file->elf, ".return_sites",
sizeof(int), idx);
if (!sec) {
WARN("elf_create_section: .return_sites");
@@ -860,7 +863,7 @@ static int create_ibt_endbr_seal_sections(struct objtool_file *file)
if (!idx)
return 0;

- sec = elf_create_section(file->elf, ".ibt_endbr_seal", 0,
+ sec = elf_create_section(file->elf, ".ibt_endbr_seal",
sizeof(int), idx);
if (!sec) {
WARN("elf_create_section: .ibt_endbr_seal");
@@ -919,7 +922,7 @@ static int create_cfi_sections(struct objtool_file *file)
idx++;
}

- sec = elf_create_section(file->elf, ".cfi_sites", 0, sizeof(unsigned int), idx);
+ sec = elf_create_section(file->elf, ".cfi_sites", sizeof(unsigned int), idx);
if (!sec)
return -1;

@@ -967,7 +970,7 @@ static int create_mcount_loc_sections(struct objtool_file *file)
list_for_each_entry(insn, &file->mcount_loc_list, call_node)
idx++;

- sec = elf_create_section(file->elf, "__mcount_loc", 0, addrsize, idx);
+ sec = elf_create_section(file->elf, "__mcount_loc", addrsize, idx);
if (!sec)
return -1;

@@ -1012,7 +1015,7 @@ static int create_direct_call_sections(struct objtool_file *file)
list_for_each_entry(insn, &file->call_list, call_node)
idx++;

- sec = elf_create_section(file->elf, ".call_sites", 0, sizeof(unsigned int), idx);
+ sec = elf_create_section(file->elf, ".call_sites", sizeof(unsigned int), idx);
if (!sec)
return -1;

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 500e92979a31..7598c0a2633d 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -1059,7 +1059,7 @@ static int elf_add_string(struct elf *elf, struct section *strtab, char *str)
}

struct section *elf_create_section(struct elf *elf, const char *name,
- unsigned int sh_flags, size_t entsize, int nr)
+ size_t entsize, int nr)
{
struct section *sec, *shstrtab;
size_t size = entsize * nr;
@@ -1117,7 +1117,7 @@ struct section *elf_create_section(struct elf *elf, const char *name,
sec->sh.sh_entsize = entsize;
sec->sh.sh_type = SHT_PROGBITS;
sec->sh.sh_addralign = 1;
- sec->sh.sh_flags = SHF_ALLOC | sh_flags;
+ sec->sh.sh_flags = SHF_ALLOC;

/* Add section name to .shstrtab (or .strtab for Clang) */
shstrtab = find_section_by_name(elf, ".shstrtab");
@@ -1153,7 +1153,7 @@ static struct section *elf_create_rel_reloc_section(struct elf *elf, struct sect
strcpy(relocname, ".rel");
strcat(relocname, base->name);

- sec = elf_create_section(elf, relocname, 0, sizeof(GElf_Rel), 0);
+ sec = elf_create_section(elf, relocname, sizeof(GElf_Rel), 0);
free(relocname);
if (!sec)
return NULL;
@@ -1185,9 +1185,9 @@ static struct section *elf_create_rela_reloc_section(struct elf *elf, struct sec
strcat(relocname, base->name);

if (addrsize == sizeof(u32))
- sec = elf_create_section(elf, relocname, 0, sizeof(Elf32_Rela), 0);
+ sec = elf_create_section(elf, relocname, sizeof(Elf32_Rela), 0);
else
- sec = elf_create_section(elf, relocname, 0, sizeof(GElf_Rela), 0);
+ sec = elf_create_section(elf, relocname, sizeof(GElf_Rela), 0);
free(relocname);
if (!sec)
return NULL;
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index b24f83e7ca34..2c28aeeb3cb2 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -109,7 +109,7 @@ struct elf {
};

struct elf *elf_open_read(const char *name, int flags);
-struct section *elf_create_section(struct elf *elf, const char *name, unsigned int sh_flags, size_t entsize, int nr);
+struct section *elf_create_section(struct elf *elf, const char *name, size_t entsize, int nr);

struct symbol *elf_create_prefix_symbol(struct elf *elf, struct symbol *orig, long size);

diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c
index 48efd1e2f00d..d5f750be7d7d 100644
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -237,12 +237,12 @@ int orc_create(struct objtool_file *file)
WARN("file already has .orc_unwind section, skipping");
return -1;
}
- orc_sec = elf_create_section(file->elf, ".orc_unwind", 0,
+ orc_sec = elf_create_section(file->elf, ".orc_unwind",
sizeof(struct orc_entry), nr);
if (!orc_sec)
return -1;

- sec = elf_create_section(file->elf, ".orc_unwind_ip", 0, sizeof(int), nr);
+ sec = elf_create_section(file->elf, ".orc_unwind_ip", sizeof(int), nr);
if (!sec)
return -1;

--
2.40.1

2023-06-09 08:05:53

by tip-bot2 for Alexey Makhalov

Subject: [tip: objtool/core] objtool: Remove flags argument from elf_create_section()

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

Commit-ID: 2707579dfa615a5dda4aabb92e433f03a87b5ec5
Gitweb: https://git.kernel.org/tip/2707579dfa615a5dda4aabb92e433f03a87b5ec5
Author: Josh Poimboeuf <[email protected]>
AuthorDate: Tue, 30 May 2023 10:20:54 -07:00
Committer: Josh Poimboeuf <[email protected]>
CommitterDate: Wed, 07 Jun 2023 10:03:13 -07:00

objtool: Remove flags argument from elf_create_section()

Simplify the elf_create_section() interface a bit by removing the flags
argument. Most callers don't care about changing the section header
flags. If needed, they can be modified afterwards, just like any other
section header field.

Link: https://lore.kernel.org/r/515235d9cf62637a14bee37bfa9169ef20065471.1685464332.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <[email protected]>
---
tools/objtool/check.c | 17 ++++++++++-------
tools/objtool/elf.c | 10 +++++-----
tools/objtool/include/objtool/elf.h | 2 +-
tools/objtool/orc_gen.c | 4 ++--
4 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index b11c25a..eaf6815 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -677,11 +677,14 @@ static int create_static_call_sections(struct objtool_file *file)
list_for_each_entry(insn, &file->static_call_list, call_node)
idx++;

- sec = elf_create_section(file->elf, ".static_call_sites", SHF_WRITE,
+ sec = elf_create_section(file->elf, ".static_call_sites",
sizeof(struct static_call_site), idx);
if (!sec)
return -1;

+ /* Allow modules to set the low bits of static_call_site::key */
+ sec->sh.sh_flags |= SHF_WRITE;
+
idx = 0;
list_for_each_entry(insn, &file->static_call_list, call_node) {

@@ -763,7 +766,7 @@ static int create_retpoline_sites_sections(struct objtool_file *file)
if (!idx)
return 0;

- sec = elf_create_section(file->elf, ".retpoline_sites", 0,
+ sec = elf_create_section(file->elf, ".retpoline_sites",
sizeof(int), idx);
if (!sec) {
WARN("elf_create_section: .retpoline_sites");
@@ -809,7 +812,7 @@ static int create_return_sites_sections(struct objtool_file *file)
if (!idx)
return 0;

- sec = elf_create_section(file->elf, ".return_sites", 0,
+ sec = elf_create_section(file->elf, ".return_sites",
sizeof(int), idx);
if (!sec) {
WARN("elf_create_section: .return_sites");
@@ -861,7 +864,7 @@ static int create_ibt_endbr_seal_sections(struct objtool_file *file)
if (!idx)
return 0;

- sec = elf_create_section(file->elf, ".ibt_endbr_seal", 0,
+ sec = elf_create_section(file->elf, ".ibt_endbr_seal",
sizeof(int), idx);
if (!sec) {
WARN("elf_create_section: .ibt_endbr_seal");
@@ -920,7 +923,7 @@ static int create_cfi_sections(struct objtool_file *file)
idx++;
}

- sec = elf_create_section(file->elf, ".cfi_sites", 0, sizeof(unsigned int), idx);
+ sec = elf_create_section(file->elf, ".cfi_sites", sizeof(unsigned int), idx);
if (!sec)
return -1;

@@ -968,7 +971,7 @@ static int create_mcount_loc_sections(struct objtool_file *file)
list_for_each_entry(insn, &file->mcount_loc_list, call_node)
idx++;

- sec = elf_create_section(file->elf, "__mcount_loc", 0, addrsize, idx);
+ sec = elf_create_section(file->elf, "__mcount_loc", addrsize, idx);
if (!sec)
return -1;

@@ -1013,7 +1016,7 @@ static int create_direct_call_sections(struct objtool_file *file)
list_for_each_entry(insn, &file->call_list, call_node)
idx++;

- sec = elf_create_section(file->elf, ".call_sites", 0, sizeof(unsigned int), idx);
+ sec = elf_create_section(file->elf, ".call_sites", sizeof(unsigned int), idx);
if (!sec)
return -1;

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 500e929..7598c0a 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -1059,7 +1059,7 @@ static int elf_add_string(struct elf *elf, struct section *strtab, char *str)
}

struct section *elf_create_section(struct elf *elf, const char *name,
- unsigned int sh_flags, size_t entsize, int nr)
+ size_t entsize, int nr)
{
struct section *sec, *shstrtab;
size_t size = entsize * nr;
@@ -1117,7 +1117,7 @@ struct section *elf_create_section(struct elf *elf, const char *name,
sec->sh.sh_entsize = entsize;
sec->sh.sh_type = SHT_PROGBITS;
sec->sh.sh_addralign = 1;
- sec->sh.sh_flags = SHF_ALLOC | sh_flags;
+ sec->sh.sh_flags = SHF_ALLOC;

/* Add section name to .shstrtab (or .strtab for Clang) */
shstrtab = find_section_by_name(elf, ".shstrtab");
@@ -1153,7 +1153,7 @@ static struct section *elf_create_rel_reloc_section(struct elf *elf, struct sect
strcpy(relocname, ".rel");
strcat(relocname, base->name);

- sec = elf_create_section(elf, relocname, 0, sizeof(GElf_Rel), 0);
+ sec = elf_create_section(elf, relocname, sizeof(GElf_Rel), 0);
free(relocname);
if (!sec)
return NULL;
@@ -1185,9 +1185,9 @@ static struct section *elf_create_rela_reloc_section(struct elf *elf, struct sec
strcat(relocname, base->name);

if (addrsize == sizeof(u32))
- sec = elf_create_section(elf, relocname, 0, sizeof(Elf32_Rela), 0);
+ sec = elf_create_section(elf, relocname, sizeof(Elf32_Rela), 0);
else
- sec = elf_create_section(elf, relocname, 0, sizeof(GElf_Rela), 0);
+ sec = elf_create_section(elf, relocname, sizeof(GElf_Rela), 0);
free(relocname);
if (!sec)
return NULL;
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index b24f83e..2c28aee 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -109,7 +109,7 @@ struct elf {
};

struct elf *elf_open_read(const char *name, int flags);
-struct section *elf_create_section(struct elf *elf, const char *name, unsigned int sh_flags, size_t entsize, int nr);
+struct section *elf_create_section(struct elf *elf, const char *name, size_t entsize, int nr);

struct symbol *elf_create_prefix_symbol(struct elf *elf, struct symbol *orig, long size);

diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c
index 48efd1e..d5f750b 100644
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -237,12 +237,12 @@ int orc_create(struct objtool_file *file)
WARN("file already has .orc_unwind section, skipping");
return -1;
}
- orc_sec = elf_create_section(file->elf, ".orc_unwind", 0,
+ orc_sec = elf_create_section(file->elf, ".orc_unwind",
sizeof(struct orc_entry), nr);
if (!orc_sec)
return -1;

- sec = elf_create_section(file->elf, ".orc_unwind_ip", 0, sizeof(int), nr);
+ sec = elf_create_section(file->elf, ".orc_unwind_ip", sizeof(int), nr);
if (!sec)
return -1;