2023-02-10 20:21:48

by Tom Saeger

[permalink] [raw]
Subject: [PATCH 5.10 v2 0/5] Fix Build ID on arm64 if CONFIG_MODVERSIONS=y

Build ID is missing for arm64 with CONFIG_MODVERSIONS=y using ld >= 2.36
on 5.4, 5.10, and 5.15

Backport BuildID fixes.

I've build tested this on {x86_64, arm64, riscv, powerpc, s390, sh}.

# view Build ID
$ readelf -n vmlinux | grep "Build ID"

Changes for v2:
- rebase 5/5 c1c551bebf92 ("sh: define RUNTIME_DISCARD_EXIT") from upstream

Previous threads:
[1] https://lore.kernel.org/all/[email protected]
[2] https://lore.kernel.org/all/3df32572ec7016e783d37e185f88495831671f5d.1671143628.git.tom.saeger@oracle.com/
[3] https://lore.kernel.org/all/[email protected]/

Signed-off-by: Tom Saeger <[email protected]>
---
Masahiro Yamada (2):
arch: fix broken BuildID for arm64 and riscv
s390: define RUNTIME_DISCARD_EXIT to fix link error with GNU ld < 2.36

Michael Ellerman (2):
powerpc/vmlinux.lds: Define RUNTIME_DISCARD_EXIT
powerpc/vmlinux.lds: Don't discard .rela* for relocatable builds

Tom Saeger (1):
sh: define RUNTIME_DISCARD_EXIT

arch/powerpc/kernel/vmlinux.lds.S | 6 +++++-
arch/s390/kernel/vmlinux.lds.S | 2 ++
arch/sh/kernel/vmlinux.lds.S | 1 +
include/asm-generic/vmlinux.lds.h | 5 +++++
4 files changed, 13 insertions(+), 1 deletion(-)
---
base-commit: a5acb54d4066f27e9707af9d93f047f542d5ad88
change-id: 20230210-tsaeger-upstream-linux-5-10-y-e443820440f6

Best regards,
--
Tom Saeger <[email protected]>



2023-02-10 20:22:06

by Tom Saeger

[permalink] [raw]
Subject: [PATCH 5.10 v2 5/5] sh: define RUNTIME_DISCARD_EXIT

commit c1c551bebf928889e7a8fef7415b44f9a64975f4 upstream.

sh vmlinux fails to link with GNU ld < 2.40 (likely < 2.36) since
commit 99cb0d917ffa ("arch: fix broken BuildID for arm64 and riscv").

This is similar to fixes for powerpc and s390:
commit 4b9880dbf3bd ("powerpc/vmlinux.lds: Define RUNTIME_DISCARD_EXIT").
commit a494398bde27 ("s390: define RUNTIME_DISCARD_EXIT to fix link error
with GNU ld < 2.36").

$ sh4-linux-gnu-ld --version | head -n1
GNU ld (GNU Binutils for Debian) 2.35.2

$ make ARCH=sh CROSS_COMPILE=sh4-linux-gnu- microdev_defconfig
$ make ARCH=sh CROSS_COMPILE=sh4-linux-gnu-

`.exit.text' referenced in section `__bug_table' of crypto/algboss.o:
defined in discarded section `.exit.text' of crypto/algboss.o
`.exit.text' referenced in section `__bug_table' of
drivers/char/hw_random/core.o: defined in discarded section
`.exit.text' of drivers/char/hw_random/core.o
make[2]: *** [scripts/Makefile.vmlinux:34: vmlinux] Error 1
make[1]: *** [Makefile:1252: vmlinux] Error 2

arch/sh/kernel/vmlinux.lds.S keeps EXIT_TEXT:

/*
* .exit.text is discarded at runtime, not link time, to deal with
* references from __bug_table
*/
.exit.text : AT(ADDR(.exit.text)) { EXIT_TEXT }

However, EXIT_TEXT is thrown away by
DISCARD(include/asm-generic/vmlinux.lds.h) because
sh does not define RUNTIME_DISCARD_EXIT.

GNU ld 2.40 does not have this issue and builds fine.
This corresponds with Masahiro's comments in a494398bde27:
"Nathan [Chancellor] also found that binutils
commit 21401fc7bf67 ("Duplicate output sections in scripts") cured this
issue, so we cannot reproduce it with binutils 2.36+, but it is better
to not rely on it."

Link: https://lkml.kernel.org/r/9166a8abdc0f979e50377e61780a4bba1dfa2f52.1674518464.git.tom.saeger@oracle.com
Fixes: 99cb0d917ffa ("arch: fix broken BuildID for arm64 and riscv")
Link: https://lore.kernel.org/all/[email protected]/
Link: https://lore.kernel.org/all/[email protected]/
Signed-off-by: Tom Saeger <[email protected]>
Tested-by: John Paul Adrian Glaubitz <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Dennis Gilmore <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Naresh Kamboju <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Rich Felker <[email protected]>
Cc: Yoshinori Sato <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Tom Saeger <[email protected]>
---
arch/sh/kernel/vmlinux.lds.S | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/sh/kernel/vmlinux.lds.S b/arch/sh/kernel/vmlinux.lds.S
index 3161b9ccd2a5..b6276a3521d7 100644
--- a/arch/sh/kernel/vmlinux.lds.S
+++ b/arch/sh/kernel/vmlinux.lds.S
@@ -4,6 +4,7 @@
* Written by Niibe Yutaka and Paul Mundt
*/
OUTPUT_ARCH(sh)
+#define RUNTIME_DISCARD_EXIT
#include <asm/thread_info.h>
#include <asm/cache.h>
#include <asm/vmlinux.lds.h>

--
2.39.1