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| author | Nathan Chancellor <nathan@kernel.org> | 2024-02-20 23:44:48 +0300 |
|---|---|---|
| committer | Heiko Carstens <hca@linux.ibm.com> | 2024-02-22 18:06:56 +0300 |
| commit | 7f115ff4fc20698452ff4a1cbb9c790be10b0066 (patch) | |
| tree | 376e9f81dfa3ca9f956098b39e793e115df159d4 | |
| parent | 559a1462909b893c52b41e2e39c364af8bacae8a (diff) | |
| download | linux-7f115ff4fc20698452ff4a1cbb9c790be10b0066.tar.xz | |
s390/boot: workaround current 'llvm-objdump -t -j ...' behavior
When building with OBJDUMP=llvm-objdump, there are a series of warnings
from the section comparisons that arch/s390/boot/Makefile performs
between vmlinux and arch/s390/boot/vmlinux:
llvm-objdump: warning: section '.boot.preserved.data' mentioned in a -j/--section option, but not found in any input file
llvm-objdump: warning: section '.boot.data' mentioned in a -j/--section option, but not found in any input file
llvm-objdump: warning: section '.boot.preserved.data' mentioned in a -j/--section option, but not found in any input file
llvm-objdump: warning: section '.boot.data' mentioned in a -j/--section option, but not found in any input file
The warning is a little misleading, as these sections do exist in the
input files. It is really pointing out that llvm-objdump does not match
GNU objdump's behavior of respecting '-j' / '--section' in combination
with '-t' / '--syms':
$ s390x-linux-gnu-objdump -t -j .boot.data vmlinux.full
vmlinux.full: file format elf64-s390
SYMBOL TABLE:
0000000001951000 l O .boot.data 0000000000003000 sclp_info_sccb
00000000019550e0 l O .boot.data 0000000000000001 sclp_info_sccb_valid
00000000019550e2 g O .boot.data 0000000000001000 early_command_line
...
$ llvm-objdump -t -j .boot.data vmlinux.full
vmlinux.full: file format elf64-s390
SYMBOL TABLE:
0000000000100040 l O .text 0000000000000010 dw_psw
0000000000000000 l df *ABS* 0000000000000000 main.c
00000000001001b0 l F .text 00000000000000c6 trace_event_raw_event_initcall_level
0000000000100280 l F .text 0000000000000100 perf_trace_initcall_level
...
It may be possible to change llvm-objdump's behavior to match GNU
objdump's behavior but the difficulty of that task has not yet been
explored. The combination of '$(OBJDUMP) -t -j' is not common in the
kernel tree on a whole, so workaround this tool difference by grepping
for the sections in the full symbol table output in a similar manner to
the sed invocation. This results in no visible change for GNU objdump
users while fixing the warnings for OBJDUMP=llvm-objdump, further
enabling use of LLVM=1 for ARCH=s390 with versions of LLVM that have
support for s390 in ld.lld and llvm-objcopy.
Reported-by: Heiko Carstens <hca@linux.ibm.com>
Closes: https://lore.kernel.org/20240219113248.16287-C-hca@linux.ibm.com/
Link: https://github.com/ClangBuiltLinux/linux/issues/859
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20240220-s390-work-around-llvm-objdump-t-j-v1-1-47bb0366a831@kernel.org
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
| -rw-r--r-- | arch/s390/boot/Makefile | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/s390/boot/Makefile b/arch/s390/boot/Makefile index aecafabc2054..294f08a8811a 100644 --- a/arch/s390/boot/Makefile +++ b/arch/s390/boot/Makefile @@ -60,9 +60,9 @@ clean-files += vmlinux.map quiet_cmd_section_cmp = SECTCMP $* define cmd_section_cmp - s1=`$(OBJDUMP) -t -j "$*" "$<" | sort | \ + s1=`$(OBJDUMP) -t "$<" | grep "\s$*\s\+" | sort | \ sed -n "/0000000000000000/! s/.*\s$*\s\+//p" | sha256sum`; \ - s2=`$(OBJDUMP) -t -j "$*" "$(word 2,$^)" | sort | \ + s2=`$(OBJDUMP) -t "$(word 2,$^)" | grep "\s$*\s\+" | sort | \ sed -n "/0000000000000000/! s/.*\s$*\s\+//p" | sha256sum`; \ if [ "$$s1" != "$$s2" ]; then \ echo "error: section $* differs between $< and $(word 2,$^)" >&2; \ |