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linux-next/scripts
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Paul Walmsley a4d26f1a09 modpost: skip ELF local symbols during section mismatch check 
During development of a serial console driver with a gcc 8.2.0
toolchain for RISC-V, the following modpost warning appeared:

----
WARNING: vmlinux.o(.data+0x19b10): Section mismatch in reference from the variable .LANCHOR1 to the function .init.text:sifive_serial_console_setup()
The variable .LANCHOR1 references
the function __init sifive_serial_console_setup()
If the reference is valid then annotate the
variable with __init* or __refdata (see linux/init.h) or name the variable:
*_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console
----

".LANCHOR1" is an ELF local symbol, automatically created by gcc's section
anchor generation code:

https://gcc.gnu.org/onlinedocs/gccint/Anchored-Addresses.html

https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/varasm.c;h=cd9591a45617464946dcf9a126dde277d9de9804;hb=9fb89fa845c1b2e0a18d85ada0b077c84508ab78#l7473

This was verified by compiling the kernel with -fno-section-anchors
and observing that the ".LANCHOR1" ELF local symbol disappeared, and
modpost no longer warned about the section mismatch.  The serial
driver code idiom triggering the warning is standard Linux serial
driver practice that has a specific whitelist inclusion in modpost.c.

I'm neither a modpost nor an ELF expert, but naively, it doesn't seem
useful for modpost to report section mismatch warnings caused by ELF
local symbols by default.  Local symbols have compiler-generated
names, and thus bypass modpost's whitelisting algorithm, which relies
on the presence of a non-autogenerated symbol name.  This increases
the likelihood that false positive warnings will be generated (as in
the above case).

Thus, disable section mismatch reporting on ELF local symbols.  The
rationale here is similar to that of commit 2e3a10a155 ("ARM: avoid
ARM binutils leaking ELF local symbols") and of similar code already
present in modpost.c:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/mod/modpost.c?h=v4.19-rc4&id=7876320f88802b22d4e2daf7eb027dd14175a0f8#n1256

This third version of the patch implements a suggestion from Masahiro
Yamada <yamada.masahiro@socionext.com> to restructure the code as an
additional pattern matching step inside secref_whitelist(), and
further improves the patch description.

Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-12-01 22:21:56 +09:00
..
basic kbuild: move bin2c back to scripts/ from scripts/basic/ 2018-07-18 01:18:05 +09:00
coccinelle Coccinelle: remove pci_alloc_consistent semantic to detect in zalloc-simple.cocci 2018-08-22 23:21:43 +09:00
dtc Merge branch 'all-dtbs' into dt/next 2018-10-04 14:16:15 -05:00
gcc-plugins stackleak: Allow runtime disabling of kernel stack erasing 2018-09-04 10:35:48 -07:00
gdb scripts/gdb/linux/tasks.py: fix get_thread_info 2018-01-19 10:09:41 -08:00
genksyms genksyms: remove symbol prefix support 2018-05-17 22:43:35 +09:00
kconfig kconfig: merge_config: avoid false positive matches from comment lines 2018-11-11 23:04:51 +09:00
ksymoops Fix dead URLs to ftp.kernel.org 2017-03-28 16:16:52 +02:00
mod modpost: skip ELF local symbols during section mismatch check 2018-12-01 22:21:56 +09:00
package builddeb: Fix inclusion of dtbs in debian package 2018-11-11 23:04:53 +09:00
selinux staging: lustre: delete the filesystem from the tree. 2018-06-05 19:22:35 +02:00
tracing scripts: Add Python 3 support to tracing/draw_functrace.py 2018-07-29 11:08:38 +09:00
.gitignore kbuild: move bin2c back to scripts/ from scripts/basic/ 2018-07-18 01:18:05 +09:00
adjust_autoksyms.sh kbuild: remove CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX 2018-05-17 22:44:57 +09:00
asn1_compiler.c ASN.1: Remove unnecessary shadowed local variable 2018-10-29 00:19:41 +09:00
bin2c.c kbuild: move bin2c back to scripts/ from scripts/basic/ 2018-07-18 01:18:05 +09:00
bloat-o-meter syscalls/core, syscalls/x86: Clean up compat syscall stub naming convention 2018-04-09 16:47:28 +02:00
bootgraph.pl scripts: Switch to more portable Perl shebang 2017-05-14 11:20:44 +09:00
bpf_helpers_doc.py bpf: change eBPF helper doc parsing script to allow for smaller indent 2018-05-17 17:34:43 +02:00
cc-can-link.sh bpfilter: check compiler capability in Kconfig 2018-06-28 13:36:39 +09:00
check_extable.sh License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
checkincludes.pl License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
checkkconfigsymbols.py checkkconfigsymbols.py: support Kconfig's 'imply' statement 2017-02-03 11:49:06 +01:00
checkpatch.pl checkpatch: remove GCC_BINARY_CONSTANT warning 2018-10-31 08:54:13 -07:00
checkstack.pl scripts: Add ppc64le support for checkstack.pl 2018-07-02 23:54:28 +10:00
checksyscalls.sh License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
checkversion.pl License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
clang-version.sh kbuild: Add a space after ! to prevent parsing as file pattern 2018-08-22 23:21:40 +09:00
cleanfile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cleanpatch License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
coccicheck coccicheck: return proper error code on fail 2018-08-14 08:58:56 +09:00
config License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
conmakehash.c
const_structs.checkpatch const_structs.checkpatch: add frequently used from Julia Lawall's list 2016-10-11 15:06:30 -07:00
decode_stacktrace.sh License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
decodecode scripts/decodecode: make it take multiline Code line 2018-01-31 17:18:34 -08:00
depmod.sh kbuild: modules_install: warn when missing System.map file 2018-09-09 09:14:07 +09:00
diffconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
documentation-file-ref-check scripts/documentation-file-ref-check: ignore sched-pelt false positive 2018-07-02 11:25:00 -06:00
export_report.pl scripts: Switch to more portable Perl shebang 2017-05-14 11:20:44 +09:00
extract_xc3028.pl MAINTAINERS & files: Canonize the e-mails I use at files 2018-05-04 06:21:06 -04:00
extract-cert.c
extract-ikconfig
extract-module-sig.pl License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
extract-sys-certs.pl License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
extract-vmlinux extract-vmlinux: Check for uncompressed image as fallback 2018-10-17 08:18:01 +02:00
faddr2line scripts/faddr2line: make the new code listing format optional 2018-06-05 09:04:37 -07:00
file-size.sh kbuild: Use ls(1) instead of stat(1) to obtain file size 2018-03-26 02:01:24 +09:00
find-unused-docs.sh scripts: Add a script to find unused documentation 2017-10-23 08:01:37 -06:00
gcc-goto.sh License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
gcc-ld License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
gcc-plugin.sh License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
gcc-version.sh License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
gcc-x86_32-has-stack-protector.sh stack-protector: test compiler capability in Kconfig and drop AUTO mode 2018-06-08 18:56:00 +09:00
gcc-x86_64-has-stack-protector.sh stack-protector: Fix test with 32-bit userland and CONFIG_64BIT=y 2018-06-25 23:21:13 +09:00
get_dvb_firmware scripts: Switch to more portable Perl shebang 2017-05-14 11:20:44 +09:00
get_maintainer.pl get_maintainer: allow option --mpath <directory> to read all files in <directory> 2018-08-22 10:52:48 -07:00
gfp-translate
headerdep.pl License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
headers_check.pl License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
headers_install.sh kbuild: Improve portability of some sed invocations 2018-03-26 02:01:18 +09:00
headers.sh License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
insert-sys-cert.c
kallsyms.c kallsyms: remove left-over Blackfin code 2018-09-10 22:54:33 +09:00
Kbuild.include kbuild: remove cc-name variable 2018-11-02 22:49:01 +09:00
Kconfig.include gcc-plugins: test plugin support in Kconfig and clean up Makefile 2018-06-11 09:16:22 +09:00
kernel-doc kernel-doc: fix declaration type determination 2018-10-18 12:20:35 -06:00
ld-version.sh License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
leaking_addresses.pl leaking_addresses: check if file name contains address 2018-04-07 08:50:34 +10:00
Lindent License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
link-vmlinux.sh kbuild: rename LDFLAGS to KBUILD_LDFLAGS 2018-08-24 08:22:08 +09:00
Makefile kbuild: consolidate Devicetree dtb build rules 2018-10-02 09:23:21 -05:00
Makefile.asm-generic Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Makefile.build Kbuild updates for v4.20 2018-10-28 13:22:35 -07:00
Makefile.clean kbuild: remove deprecated host-progs variable 2018-08-09 21:51:17 +09:00
Makefile.dtbinst DeviceTree for 4.15: 2017-11-14 18:25:40 -08:00
Makefile.extrawarn Kbuild updates for v4.20 (2nd) 2018-11-03 10:47:33 -07:00
Makefile.gcc-plugins gcc-plugins: Add STACKLEAK plugin for tracking the kernel stack 2018-09-04 10:35:47 -07:00
Makefile.headersinst Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Makefile.host kbuild: Rename HOST_LOADLIBES to KBUILD_HOSTLDLIBS 2018-07-18 01:18:05 +09:00
Makefile.kasan kasan: rework Kconfig settings 2018-02-06 18:32:47 -08:00
Makefile.kcov kcov: test compiler capability in Kconfig and correct dependency 2018-06-11 09:14:08 +09:00
Makefile.lib kbuild: consolidate Devicetree dtb build rules 2018-10-02 09:23:21 -05:00
Makefile.modbuiltin Kbuild: Makefile.modbuiltin: include auto.conf and tristate.conf mandatory 2018-08-03 00:47:00 +09:00
Makefile.modinst kbuild: remove duplicated comments about PHONY 2018-07-06 22:04:03 +09:00
Makefile.modpost kbuild: rename LDFLAGS to KBUILD_LDFLAGS 2018-08-24 08:22:08 +09:00
Makefile.modsign kbuild: remove duplicated comments about PHONY 2018-07-06 22:04:03 +09:00
Makefile.ubsan lib/ubsan: remove null-pointer checks 2018-08-10 20:19:58 -07:00
makelst License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
markup_oops.pl scripts: Switch to more portable Perl shebang 2017-05-14 11:20:44 +09:00
mkcompile_h Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
mkmakefile kbuild: simplify command line creation in scripts/mkmakefile 2018-10-04 22:56:02 +09:00
mksysmap
mkuboot.sh License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
module-common.lds module: set .init_array alignment to 8 2017-03-13 09:40:28 -07:00
namespace.pl kbuild: rename built-in.o to built-in.a 2018-03-26 02:01:19 +09:00
objdiff scripts: objdiff: Ignore debug info when comparing 2017-03-11 11:13:38 +09:00
parse-maintainers.pl parse-maintainers: add ability to specify filenames 2017-11-17 16:10:01 -08:00
patch-kernel License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pnmtologo.c
profile2linkerlist.pl License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
prune-kernel License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
recordmcount.c scripts: Fixed printf format mismatch 2018-05-29 22:04:12 +09:00
recordmcount.h scripts: Fixed printf format mismatch 2018-05-29 22:04:12 +09:00
recordmcount.pl nds32/ftrace: Add RECORD_MCOUNT support 2018-09-04 14:45:18 +08:00
setlocalversion scripts/setlocalversion: Improve -dirty check with git-status --no-optional-locks 2018-11-21 23:57:33 +09:00
show_delta
sign-file.c sign-file: fix build error in sign-file.c with libressl 2017-02-10 12:43:47 +11:00
sortextable.c powerpc: Build-time sort the exception table 2016-11-14 11:11:51 +11:00
sortextable.h
spdxcheck.py scripts: add Python 3 compatibility to spdxcheck.py 2018-08-17 16:20:27 -07:00
spelling.txt treewide: correct "differenciate" and "instanciate" typos 2018-08-23 18:48:43 -07:00
sphinx-pre-install docs-rst: don't require adjustbox anymore 2017-09-08 10:02:55 -06:00
split-man.pl MAINTAINERS & files: Canonize the e-mails I use at files 2018-05-04 06:21:06 -04:00
stackdelta License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
stackusage License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
subarch.include selftests: add headers_install to lib.mk 2018-09-05 08:12:09 -06:00
tags.sh scripts/tags.sh: add DECLARE_HASHTABLE() 2018-10-26 16:25:18 -07:00
unifdef.c
ver_linux ver_linux: Do not check for ver_linux pattern in version function 2018-07-07 17:44:52 +02:00
xen-hypercalls.sh License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xz_wrap.sh