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Masahiro Yamada bdf1b29aa5 kbuild: update config_data.gz only when the content of .config is changed
commit 46b41d5dd8019b264717978c39c43313a524d033 upstream.

If the timestamp of the .config file is updated, config_data.gz is
regenerated, then vmlinux is re-linked. This occurs even if the content
of the .config has not changed at all.

This issue was mitigated by commit 67424f61f813 ("kconfig: do not write
.config if the content is the same"); Kconfig does not update the
.config when it ends up with the identical configuration.

The issue is remaining when the .config is created by *_defconfig with
some config fragment(s) applied on top.

This is typical for powerpc and mips, where several *_defconfig targets
are constructed by using merge_config.sh.

One workaround is to have the copy of the .config. The filechk rule
updates the copy, kernel/config_data, by checking the content instead
of the timestamp.

With this commit, the second run with the same configuration avoids
the needless rebuilds.

  $ make ARCH=mips defconfig all
   [ snip ]
  $ make ARCH=mips defconfig all
  *** Default configuration is based on target '32r2el_defconfig'
  Using ./arch/mips/configs/generic_defconfig as base
  Merging arch/mips/configs/generic/32r2.config
  Merging arch/mips/configs/generic/el.config
  Merging ./arch/mips/configs/generic/board-boston.config
  Merging ./arch/mips/configs/generic/board-ni169445.config
  Merging ./arch/mips/configs/generic/board-ocelot.config
  Merging ./arch/mips/configs/generic/board-ranchu.config
  Merging ./arch/mips/configs/generic/board-sead-3.config
  Merging ./arch/mips/configs/generic/board-xilfpga.config
  #
  # configuration written to .config
  #
    SYNC    include/config/auto.conf
    CALL    scripts/checksyscalls.sh
    CALL    scripts/atomic/check-atomics.sh
    CHK     include/generated/compile.h
    CHK     include/generated/autoksyms.h

Reported-by: Elliot Berman <eberman@codeaurora.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-20 16:07:35 +08:00
Documentation dt-bindings: net: ethernet-controller: fix typo in NVMEM 2021-05-20 16:07:03 +08:00
LICENSES Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
arch x86/cpu: Initialize MSR_TSC_AUX if RDTSCP *or* RDPID is supported 2021-05-20 16:07:35 +08:00
block block: only update parent bi_status when bio fail 2021-05-20 16:07:05 +08:00
certs certs: Fix blacklist flag type confusion 2021-04-12 12:52:25 +08:00
crypto crypto: rng - fix crypto_rng_reset() refcounting when !CRYPTO_STATS 2021-05-20 16:07:34 +08:00
drivers Fix misc new gcc warnings 2021-05-20 16:07:35 +08:00
fs jffs2: check the validity of dstlen in jffs2_zlib_compress() 2021-05-20 16:07:35 +08:00
include Fix misc new gcc warnings 2021-05-20 16:07:35 +08:00
init init/Kconfig: make COMPILE_TEST depend on HAS_IOMEM 2021-05-20 16:06:54 +08:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2021-03-16 16:27:51 +08:00
kernel kbuild: update config_data.gz only when the content of .config is changed 2021-05-20 16:07:35 +08:00
lib avoid __memcat_p link failure 2021-05-20 16:07:18 +08:00
mm mm: fix race by making init_zero_pfn() early_initcall 2021-05-20 16:06:49 +08:00
net Fix misc new gcc warnings 2021-05-20 16:07:35 +08:00
package net: open CONFIG_XFRM_OFFLOAD for x86 public 2021-05-18 07:22:15 +00:00
samples samples, bpf: Add missing munmap in xdpsock 2021-04-12 12:52:57 +08:00
scripts ftrace: Have recordmcount use w8 to read relp->r_info in arm64_is_fake_mcount 2021-04-12 12:52:52 +08:00
security security: commoncap: fix -Wstringop-overread warning 2021-05-20 16:07:35 +08:00
sound ALSA: hda/realtek: Add quirk for Intel Clevo PCx0Dx 2021-05-20 16:07:33 +08:00
tools perf ftrace: Fix access to pid in array when setting a pid filter 2021-05-20 16:07:18 +08:00
usr Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
virt KVM: arm64: Ensure I-cache isolation between vcpus of a same VM 2021-04-12 12:53:12 +08:00
.clang-format Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
.cocciconfig Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
.get_maintainer.ignore Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
.gitattributes Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
.gitignore Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
COPYING Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
CREDITS Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
Kbuild Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
Kconfig Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2021-03-16 16:34:24 +08:00
Makefile Makefile: Move -Wno-unused-but-set-variable out of GCC only block 2021-05-20 16:07:33 +08:00
README Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
README.md Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
backport_remove_lists.txt Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
tools_key.pub Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00

README.md

Tencent Linux Kernel 4.0