The patch 4abff6d48dbc ("objtool: Fix code relocs vs weak symbols") makes
the kernel unbootable. The patch c087c6e7b551 ("objtool: Fix type of
reloc::addend") attempts to fix it by replacing 'int' with 'long'.
However, we may be running on a system with x32 ABI and 'long' on x32 is
32-bit, thus the patch c087c6e7b551 doesn't really change anything and we
still end up with miscompiled kernel. This patch replaces 'long' with
'long long', so that the 64-bit kernel is correctly compiled on a x32
system.
Signed-off-by: Mikulas Patocka <[email protected]>
Fixes: 4abff6d48dbc ("objtool: Fix code relocs vs weak symbols")
Fixes: c087c6e7b551 ("objtool: Fix type of reloc::addend")
---
tools/objtool/check.c | 8 ++++----
tools/objtool/elf.c | 2 +-
tools/objtool/include/objtool/elf.h | 4 ++--
3 files changed, 7 insertions(+), 7 deletions(-)
Index: linux-2.6/tools/objtool/check.c
===================================================================
--- linux-2.6.orig/tools/objtool/check.c 2022-05-16 16:20:49.000000000 +0200
+++ linux-2.6/tools/objtool/check.c 2022-05-16 16:22:11.000000000 +0200
@@ -560,12 +560,12 @@ static int add_dead_ends(struct objtool_
else if (reloc->addend == reloc->sym->sec->sh.sh_size) {
insn = find_last_insn(file, reloc->sym->sec);
if (!insn) {
- WARN("can't find unreachable insn at %s+0x%lx",
+ WARN("can't find unreachable insn at %s+0x%llx",
reloc->sym->sec->name, reloc->addend);
return -1;
}
} else {
- WARN("can't find unreachable insn at %s+0x%lx",
+ WARN("can't find unreachable insn at %s+0x%llx",
reloc->sym->sec->name, reloc->addend);
return -1;
}
@@ -595,12 +595,12 @@ reachable:
else if (reloc->addend == reloc->sym->sec->sh.sh_size) {
insn = find_last_insn(file, reloc->sym->sec);
if (!insn) {
- WARN("can't find reachable insn at %s+0x%lx",
+ WARN("can't find reachable insn at %s+0x%llx",
reloc->sym->sec->name, reloc->addend);
return -1;
}
} else {
- WARN("can't find reachable insn at %s+0x%lx",
+ WARN("can't find reachable insn at %s+0x%llx",
reloc->sym->sec->name, reloc->addend);
return -1;
}
Index: linux-2.6/tools/objtool/elf.c
===================================================================
--- linux-2.6.orig/tools/objtool/elf.c 2022-05-16 16:20:49.000000000 +0200
+++ linux-2.6/tools/objtool/elf.c 2022-05-16 16:22:21.000000000 +0200
@@ -546,7 +546,7 @@ static struct section *elf_create_reloc_
int reltype);
int elf_add_reloc(struct elf *elf, struct section *sec, unsigned long offset,
- unsigned int type, struct symbol *sym, long addend)
+ unsigned int type, struct symbol *sym, long long addend)
{
struct reloc *reloc;
Index: linux-2.6/tools/objtool/include/objtool/elf.h
===================================================================
--- linux-2.6.orig/tools/objtool/include/objtool/elf.h 2022-05-16 16:07:54.000000000 +0200
+++ linux-2.6/tools/objtool/include/objtool/elf.h 2022-05-16 16:22:45.000000000 +0200
@@ -73,7 +73,7 @@ struct reloc {
struct symbol *sym;
unsigned long offset;
unsigned int type;
- long addend;
+ long long addend;
int idx;
bool jump_table_start;
};
@@ -135,7 +135,7 @@ struct elf *elf_open_read(const char *na
struct section *elf_create_section(struct elf *elf, const char *name, unsigned int sh_flags, size_t entsize, int nr);
int elf_add_reloc(struct elf *elf, struct section *sec, unsigned long offset,
- unsigned int type, struct symbol *sym, long addend);
+ unsigned int type, struct symbol *sym, long long addend);
int elf_add_reloc_to_insn(struct elf *elf, struct section *sec,
unsigned long offset, unsigned int type,
struct section *insn_sec, unsigned long insn_off);
On Tue, May 17, 2022 at 08:26:42AM +0000, David Laight wrote:
> From: Peter Zijlstra
> > Sent: 16 May 2022 22:25
> ...
> > A quick look seems to suggest at least all the 'offset' fields should be
> > u64 or something. The only reason that works is because -mcmodel=kernel
> > keeps everything in the 2G range to make s32 immediates work. But it
> > isn't right.
>
> Offsets in instructions are only 8bit or 32bit.
> The mod/reg/rm and SiB encodings don't support anything else.
> If offsets might be large then they have to be loaded into
> registers - which will slow things down.
Not relevant; these are Elf64_Addr fields, objtool currently uses
'unsigned long' for them, but that goes sideways if ILP32.