brain-hackers_pepepper-mirror/linux-brain
1
0
Fork 0
mirror of https://github.com/brain-hackers/linux-brain.git synced 2024-06-09 15:26:21 +09:00
Code Issues Projects Releases Wiki Activity
Linux kernel source tree for SHARP Brain series (PW-SH1 or later)
722,494 Commits 19 Branches 467 Tags 3.3 GiB
C 97.8%
Assembly 1.4%
Makefile 0.3%
Shell 0.2%
Python 0.1%
Other 0.1%
4d64f26e2a
Go to file
Paul Walmsley 4d64f26e2a modpost: skip ELF local symbols during section mismatch check 
[ Upstream commit a4d26f1a09 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-12-17 20:38:30 +01:00
arch ARM: dts: realview-pbx: Fix duplicate regulator nodes 2019-12-17 20:38:27 +01:00
block block: fix the DISCARD request merge 2019-12-01 09:13:49 +01:00
certs Replace magic for trusting the secondary keyring with #define 2018-09-09 19:55:54 +02:00
crypto crypto: ecc - check for invalid values in the key verification test 2019-12-17 20:37:54 +01:00
Documentation rtc: dt-binding: abx80x: fix resistance scale 2019-12-17 20:38:04 +01:00
drivers i2c: imx: don't print error message on probe defer 2019-12-17 20:38:15 +01:00
firmware License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fs nfsd: fix a warning in __cld_pipe_upcall() 2019-12-17 20:38:18 +01:00
include dma-mapping: fix return type of dma_set_max_seg_size() 2019-12-17 20:38:13 +01:00
init fork: fix some -Wmissing-prototypes warnings 2019-12-05 15:37:52 +01:00
ipc ipc/mqueue.c: only perform resource calculation if user valid 2019-08-06 19:05:24 +02:00
kernel sched/core: Avoid spurious lock dependencies 2019-12-17 20:37:29 +01:00
lib lib/genalloc.c: include vmalloc.h 2019-12-05 15:37:53 +01:00
mm mm/vmstat.c: fix NUMA statistics updates 2019-12-17 20:37:57 +01:00
net tcp: fix SNMP TCP timeout under-estimation 2019-12-17 20:38:29 +01:00
samples vfio-mdev/samples: Use u8 instead of char for handle functions 2019-12-05 15:37:27 +01:00
scripts modpost: skip ELF local symbols during section mismatch check 2019-12-17 20:38:30 +01:00
security apparmor: delete the dentry in aafs_remove() to avoid a leak 2019-12-05 15:38:01 +01:00
sound ASoC: au8540: use 64-bit arithmetic instead of 32-bit 2019-12-17 20:38:19 +01:00
tools usbip: tools: fix fd leakage in the function of read_attr_usbip_status 2019-12-01 09:14:29 +01:00
usr kbuild: clean compressed initramfs image 2019-10-07 18:55:14 +02:00
virt kvm: properly check debugfs dentry before using it 2019-12-05 15:37:59 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: rpm-pkg: keep spec file until make mrproper 2018-02-13 10:19:46 +01:00
.mailmap .mailmap: Add Maciej W. Rozycki's Imagination e-mail address 2017-11-10 12:16:15 -08:00
COPYING
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS USB: rio500: Remove Rio 500 kernel driver 2019-10-17 13:43:20 -07:00
Makefile Linux 4.14.158 2019-12-05 15:38:36 +01:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

README 

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.