linux-kernel - [tip: x86/core] objtool: Extract elf_strtab

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Date:   Sat, 03 Apr 2021 11:10:57 -0000
From:   "tip-bot2 for Peter Zijlstra" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Borislav Petkov <bp@...e.de>, Ingo Molnar <mingo@...nel.org>,
        Miroslav Benes <mbenes@...e.cz>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: x86/core] objtool: Extract elf_strtab_concat()

The following commit has been merged into the x86/core branch of tip:

Commit-ID:     417a4dc91e559f92404c2544f785b02ce75784c3
Gitweb:        https://git.kernel.org/tip/417a4dc91e559f92404c2544f785b02ce75784c3
Author:        Peter Zijlstra <peterz@...radead.org>
AuthorDate:    Fri, 26 Mar 2021 16:12:09 +01:00
Committer:     Ingo Molnar <mingo@...nel.org>
CommitterDate: Fri, 02 Apr 2021 12:44:56 +02:00

objtool: Extract elf_strtab_concat()

Create a common helper to append strings to a strtab.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Signed-off-by: Borislav Petkov <bp@...e.de>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Reviewed-by: Miroslav Benes <mbenes@...e.cz>
Link: https://lkml.kernel.org/r/20210326151259.941474004@infradead.org
---
 tools/objtool/elf.c | 60 +++++++++++++++++++++++++++-----------------
 1 file changed, 38 insertions(+), 22 deletions(-)

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 7b65ae3..c278a04 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -673,13 +673,48 @@ err:
 	return NULL;
 }
 
+static int elf_add_string(struct elf *elf, struct section *strtab, char *str)
+{
+	Elf_Data *data;
+	Elf_Scn *s;
+	int len;
+
+	if (!strtab)
+		strtab = find_section_by_name(elf, ".strtab");
+	if (!strtab) {
+		WARN("can't find .strtab section");
+		return -1;
+	}
+
+	s = elf_getscn(elf->elf, strtab->idx);
+	if (!s) {
+		WARN_ELF("elf_getscn");
+		return -1;
+	}
+
+	data = elf_newdata(s);
+	if (!data) {
+		WARN_ELF("elf_newdata");
+		return -1;
+	}
+
+	data->d_buf = str;
+	data->d_size = strlen(str) + 1;
+	data->d_align = 1;
+
+	len = strtab->len;
+	strtab->len += data->d_size;
+	strtab->changed = true;
+
+	return len;
+}
+
 struct section *elf_create_section(struct elf *elf, const char *name,
 				   unsigned int sh_flags, size_t entsize, int nr)
 {
 	struct section *sec, *shstrtab;
 	size_t size = entsize * nr;
 	Elf_Scn *s;
-	Elf_Data *data;
 
 	sec = malloc(sizeof(*sec));
 	if (!sec) {
@@ -736,7 +771,6 @@ struct section *elf_create_section(struct elf *elf, const char *name,
 	sec->sh.sh_addralign = 1;
 	sec->sh.sh_flags = SHF_ALLOC | sh_flags;
 
-
 	/* Add section name to .shstrtab (or .strtab for Clang) */
 	shstrtab = find_section_by_name(elf, ".shstrtab");
 	if (!shstrtab)
@@ -745,27 +779,9 @@ struct section *elf_create_section(struct elf *elf, const char *name,
 		WARN("can't find .shstrtab or .strtab section");
 		return NULL;
 	}
-
-	s = elf_getscn(elf->elf, shstrtab->idx);
-	if (!s) {
-		WARN_ELF("elf_getscn");
+	sec->sh.sh_name = elf_add_string(elf, shstrtab, sec->name);
+	if (sec->sh.sh_name == -1)
 		return NULL;
-	}
-
-	data = elf_newdata(s);
-	if (!data) {
-		WARN_ELF("elf_newdata");
-		return NULL;
-	}
-
-	data->d_buf = sec->name;
-	data->d_size = strlen(name) + 1;
-	data->d_align = 1;
-
-	sec->sh.sh_name = shstrtab->len;
-
-	shstrtab->len += strlen(name) + 1;
-	shstrtab->changed = true;
 
 	list_add_tail(&sec->list, &elf->sections);
 	elf_hash_add(elf->section_hash, &sec->hash, sec->idx);