[PATCH v3 2/6] objtool: Add architecture specific R_REL32 macro

From: Christophe Leroy
Date: Thu Sep 01 2022 - 07:49:52 EST


In order to allow other architectures than x86 to use 32 bits
PC relative relocations (S+A-P), define a R_REL32 macro that each
architecture will define, in the same way as already done for
R_NONE, R_ABS32 and R_ABS64.

For x86 that corresponds to R_X86_64_PC32.
For powerpc it is R_PPC_REL32/R_PPC64_REL32.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
v3: Added powerpc in the patch
v2: Improved commit message based on feedback from Segher
---
tools/objtool/arch/powerpc/include/arch/elf.h | 1 +
tools/objtool/arch/x86/include/arch/elf.h | 1 +
tools/objtool/check.c | 10 +++++-----
tools/objtool/orc_gen.c | 2 +-
4 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/tools/objtool/arch/powerpc/include/arch/elf.h b/tools/objtool/arch/powerpc/include/arch/elf.h
index 73f9ae172fe5..befc2e30d38b 100644
--- a/tools/objtool/arch/powerpc/include/arch/elf.h
+++ b/tools/objtool/arch/powerpc/include/arch/elf.h
@@ -6,5 +6,6 @@
#define R_NONE R_PPC_NONE
#define R_ABS64 R_PPC64_ADDR64
#define R_ABS32 R_PPC_ADDR32
+#define R_REL32 R_PPC_REL32 /* R_PPC64_REL32 is identical */

#endif /* _OBJTOOL_ARCH_ELF */
diff --git a/tools/objtool/arch/x86/include/arch/elf.h b/tools/objtool/arch/x86/include/arch/elf.h
index ac14987cf687..e7d228c686db 100644
--- a/tools/objtool/arch/x86/include/arch/elf.h
+++ b/tools/objtool/arch/x86/include/arch/elf.h
@@ -4,5 +4,6 @@
#define R_NONE R_X86_64_NONE
#define R_ABS64 R_X86_64_64
#define R_ABS32 R_X86_64_32
+#define R_REL32 R_X86_64_PC32

#endif /* _OBJTOOL_ARCH_ELF */
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 9ee48d0761f0..00fdaa86db70 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -655,7 +655,7 @@ static int create_static_call_sections(struct objtool_file *file)
/* populate reloc for 'addr' */
if (elf_add_reloc_to_insn(file->elf, sec,
idx * sizeof(struct static_call_site),
- R_X86_64_PC32,
+ R_REL32,
insn->sec, insn->offset))
return -1;

@@ -696,7 +696,7 @@ static int create_static_call_sections(struct objtool_file *file)
/* populate reloc for 'key' */
if (elf_add_reloc(file->elf, sec,
idx * sizeof(struct static_call_site) + 4,
- R_X86_64_PC32, key_sym,
+ R_REL32, key_sym,
is_sibling_call(insn) * STATIC_CALL_SITE_TAIL))
return -1;

@@ -740,7 +740,7 @@ static int create_retpoline_sites_sections(struct objtool_file *file)

if (elf_add_reloc_to_insn(file->elf, sec,
idx * sizeof(int),
- R_X86_64_PC32,
+ R_REL32,
insn->sec, insn->offset)) {
WARN("elf_add_reloc_to_insn: .retpoline_sites");
return -1;
@@ -838,7 +838,7 @@ static int create_ibt_endbr_seal_sections(struct objtool_file *file)

if (elf_add_reloc_to_insn(file->elf, sec,
idx * sizeof(int),
- R_X86_64_PC32,
+ R_REL32,
insn->sec, insn->offset)) {
WARN("elf_add_reloc_to_insn: .ibt_endbr_seal");
return -1;
@@ -4004,7 +4004,7 @@ static int validate_ibt_insn(struct objtool_file *file, struct instruction *insn
continue;

off = reloc->sym->offset;
- if (reloc->type == R_X86_64_PC32 || reloc->type == R_X86_64_PLT32)
+ if (reloc->type == R_REL32 || reloc->type == R_X86_64_PLT32)
off += arch_dest_reloc_offset(reloc->addend);
else
off += reloc->addend;
diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c
index 1f22b7ebae58..49a877b9c879 100644
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -101,7 +101,7 @@ static int write_orc_entry(struct elf *elf, struct section *orc_sec,
orc->bp_offset = bswap_if_needed(elf, orc->bp_offset);

/* populate reloc for ip */
- if (elf_add_reloc_to_insn(elf, ip_sec, idx * sizeof(int), R_X86_64_PC32,
+ if (elf_add_reloc_to_insn(elf, ip_sec, idx * sizeof(int), R_REL32,
insn_sec, insn_off))
return -1;

--
2.37.1