From: "tip-bot2 for Peter Zijlstra" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>,
Borislav Petkov <bp@suse.de>, Miroslav Benes <mbenes@suse.cz>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: x86/core] objtool: Add elf_create_undef_symbol()
Date: Thu, 01 Apr 2021 15:08:55 -0000 [thread overview]
Message-ID: <161728973533.29796.18219156552513333991.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20210326151300.064743095@infradead.org>
The following commit has been merged into the x86/core branch of tip:
Commit-ID: 993b477acdb652c6134e5faae05e8a378911cbb3
Gitweb: https://git.kernel.org/tip/993b477acdb652c6134e5faae05e8a378911cbb3
Author: Peter Zijlstra <peterz@infradead.org>
AuthorDate: Fri, 26 Mar 2021 16:12:11 +01:00
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Thu, 01 Apr 2021 13:12:48 +02:00
objtool: Add elf_create_undef_symbol()
Allow objtool to create undefined symbols; this allows creating
relocations to symbols not currently in the symbol table.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lkml.kernel.org/r/20210326151300.064743095@infradead.org
---
tools/objtool/elf.c | 60 ++++++++++++++++++++++++++++-
tools/objtool/include/objtool/elf.h | 1 +-
2 files changed, 61 insertions(+)
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 8457218..d08f5f3 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -715,6 +715,66 @@ static int elf_add_string(struct elf *elf, struct section *strtab, char *str)
return len;
}
+struct symbol *elf_create_undef_symbol(struct elf *elf, const char *name)
+{
+ struct section *symtab;
+ struct symbol *sym;
+ Elf_Data *data;
+ Elf_Scn *s;
+
+ sym = malloc(sizeof(*sym));
+ if (!sym) {
+ perror("malloc");
+ return NULL;
+ }
+ memset(sym, 0, sizeof(*sym));
+
+ sym->name = strdup(name);
+
+ sym->sym.st_name = elf_add_string(elf, NULL, sym->name);
+ if (sym->sym.st_name == -1)
+ return NULL;
+
+ sym->sym.st_info = GELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
+ // st_other 0
+ // st_shndx 0
+ // st_value 0
+ // st_size 0
+
+ symtab = find_section_by_name(elf, ".symtab");
+ if (!symtab) {
+ WARN("can't find .symtab");
+ return NULL;
+ }
+
+ s = elf_getscn(elf->elf, symtab->idx);
+ if (!s) {
+ WARN_ELF("elf_getscn");
+ return NULL;
+ }
+
+ data = elf_newdata(s);
+ if (!data) {
+ WARN_ELF("elf_newdata");
+ return NULL;
+ }
+
+ data->d_buf = &sym->sym;
+ data->d_size = sizeof(sym->sym);
+ data->d_align = 1;
+
+ sym->idx = symtab->len / sizeof(sym->sym);
+
+ symtab->len += data->d_size;
+ symtab->changed = true;
+
+ sym->sec = find_section_by_index(elf, 0);
+
+ elf_add_symbol(elf, sym);
+
+ return sym;
+}
+
struct section *elf_create_section(struct elf *elf, const char *name,
unsigned int sh_flags, size_t entsize, int nr)
{
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index 463f329..45e5ede 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -133,6 +133,7 @@ int elf_write_insn(struct elf *elf, struct section *sec,
unsigned long offset, unsigned int len,
const char *insn);
int elf_write_reloc(struct elf *elf, struct reloc *reloc);
+struct symbol *elf_create_undef_symbol(struct elf *elf, const char *name);
int elf_write(struct elf *elf);
void elf_close(struct elf *elf);
next prev parent reply other threads:[~2021-04-01 17:46 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-26 15:11 [PATCH v3 00/16] x86,objtool: Optimize !RETPOLINE Peter Zijlstra
2021-03-26 15:12 ` [PATCH v3 01/16] x86: Add insn_decode_kernel() Peter Zijlstra
2021-04-01 15:08 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2021-03-26 15:12 ` [PATCH v3 02/16] x86/alternatives: Optimize optimize_nops() Peter Zijlstra
2021-04-01 15:08 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2021-04-03 11:11 ` tip-bot2 for Peter Zijlstra
2021-03-26 15:12 ` [PATCH v3 03/16] x86/retpoline: Simplify retpolines Peter Zijlstra
2021-04-01 15:08 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2021-04-03 11:10 ` tip-bot2 for Peter Zijlstra
2021-04-06 8:56 ` David Laight
2021-03-26 15:12 ` [PATCH v3 04/16] objtool: Correctly handle retpoline thunk calls Peter Zijlstra
2021-04-01 15:08 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2021-04-03 11:10 ` tip-bot2 for Peter Zijlstra
2021-03-26 15:12 ` [PATCH v3 05/16] objtool: Per arch retpoline naming Peter Zijlstra
2021-04-01 15:08 ` [tip: x86/core] objtool: Handle per " tip-bot2 for Peter Zijlstra
2021-04-03 11:10 ` tip-bot2 for Peter Zijlstra
2021-03-26 15:12 ` [PATCH v3 06/16] objtool: Fix static_call list generation Peter Zijlstra
2021-04-01 15:08 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2021-04-03 11:10 ` tip-bot2 for Peter Zijlstra
2021-03-26 15:12 ` [PATCH v3 07/16] objtool: Rework rebuild_reloc logic Peter Zijlstra
2021-04-01 15:08 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2021-04-03 11:10 ` [tip: x86/core] objtool: Rework the elf_rebuild_reloc_section() logic tip-bot2 for Peter Zijlstra
2021-03-26 15:12 ` [PATCH v3 08/16] objtool: Add elf_create_reloc() helper Peter Zijlstra
2021-04-01 15:08 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2021-04-03 11:10 ` tip-bot2 for Peter Zijlstra
2021-03-26 15:12 ` [PATCH v3 09/16] objtool: Implicitly create reloc sections Peter Zijlstra
2021-04-01 15:08 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2021-04-03 11:10 ` [tip: x86/core] objtool: Create reloc sections implicitly tip-bot2 for Peter Zijlstra
2021-03-26 15:12 ` [PATCH v3 10/16] objtool: Extract elf_strtab_concat() Peter Zijlstra
2021-04-01 15:08 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2021-04-03 11:10 ` tip-bot2 for Peter Zijlstra
2021-03-26 15:12 ` [PATCH v3 11/16] objtool: Extract elf_symbol_add() Peter Zijlstra
2021-04-01 15:08 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2021-04-03 11:10 ` tip-bot2 for Peter Zijlstra
2021-03-26 15:12 ` [PATCH v3 12/16] objtool: Add elf_create_undef_symbol() Peter Zijlstra
2021-04-01 15:08 ` tip-bot2 for Peter Zijlstra [this message]
2021-04-03 11:10 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2021-03-26 15:12 ` [PATCH v3 13/16] objtool: Keep track of retpoline call sites Peter Zijlstra
2021-04-01 15:08 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2021-04-03 11:10 ` tip-bot2 for Peter Zijlstra
2021-03-26 15:12 ` [PATCH v3 14/16] objtool: Cache instruction relocs Peter Zijlstra
2021-04-01 15:08 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2021-04-03 11:10 ` tip-bot2 for Peter Zijlstra
2021-03-26 15:12 ` [PATCH v3 15/16] objtool: Skip magical retpoline .altinstr_replacement Peter Zijlstra
2021-04-01 15:08 ` [tip: x86/core] " tip-bot2 for Peter Zijlstra
2021-04-03 11:10 ` tip-bot2 for Peter Zijlstra
2021-03-26 15:12 ` [PATCH v3 16/16] objtool,x86: Rewrite retpoline thunk calls Peter Zijlstra
2021-03-29 16:38 ` Josh Poimboeuf
2021-06-02 15:51 ` Lukasz Majczak
2021-06-02 16:56 ` Peter Zijlstra
2021-06-02 17:10 ` Peter Zijlstra
2021-06-02 20:43 ` Josh Poimboeuf
2021-06-04 20:50 ` Nick Desaulniers
2021-06-04 23:27 ` Nick Desaulniers
2021-06-04 23:50 ` Fangrui Song
2021-06-05 10:38 ` Peter Zijlstra
2021-06-06 1:58 ` Fāng-ruì Sòng
2021-06-07 7:56 ` Peter Zijlstra
2021-06-07 9:22 ` Peter Zijlstra
2021-06-07 9:45 ` Peter Zijlstra
2021-06-07 17:23 ` Fāng-ruì Sòng
2021-06-07 18:25 ` Peter Zijlstra
2021-06-07 20:54 ` Nick Desaulniers
2021-06-08 9:56 ` Peter Zijlstra
2021-06-08 16:58 ` Nathan Chancellor
2021-06-08 17:22 ` Peter Zijlstra
2021-06-08 17:29 ` Nathan Chancellor
2021-06-08 18:17 ` Peter Zijlstra
2021-06-08 18:49 ` Nathan Chancellor
2021-06-09 7:11 ` Lukasz Majczak
2021-06-09 7:20 ` Peter Zijlstra
2021-06-09 12:23 ` Lukasz Majczak
2021-06-09 15:08 ` Peter Zijlstra
2021-06-09 15:11 ` Peter Zijlstra
2021-06-09 15:56 ` Nathan Chancellor
2021-06-08 18:18 ` Nick Desaulniers
2021-06-07 18:19 ` Peter Zijlstra
2021-06-07 18:27 ` Fāng-ruì Sòng
2021-06-07 18:47 ` Peter Zijlstra
2021-04-01 15:08 ` [tip: x86/core] objtool/x86: " tip-bot2 for Peter Zijlstra
2021-04-03 11:10 ` tip-bot2 for Peter Zijlstra
2021-03-30 15:02 ` [PATCH v3 00/16] x86,objtool: Optimize !RETPOLINE Miroslav Benes
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