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2df8220cc5
Kbuild builds init/built-in.a twice; first during the ordinary
directory descending, second from scripts/link-vmlinux.sh.
We do this because UTS_VERSION contains the build version and the
timestamp. We cannot update it during the normal directory traversal
since we do not yet know if we need to update vmlinux. UTS_VERSION is
temporarily calculated, but omitted from the update check. Otherwise,
vmlinux would be rebuilt every time.
When Kbuild results in running link-vmlinux.sh, it increments the
version number in the .version file and takes the timestamp at that
time to really fix UTS_VERSION.
However, updating the same file twice is a footgun. To avoid nasty
timestamp issues, all build artifacts that depend on init/built-in.a
are atomically generated in link-vmlinux.sh, where some of them do not
need rebuilding.
To fix this issue, this commit changes as follows:
[1] Split UTS_VERSION out to include/generated/utsversion.h from
include/generated/compile.h
include/generated/utsversion.h is generated just before the
vmlinux link. It is generated under include/generated/ because
some decompressors (s390, x86) use UTS_VERSION.
[2] Split init_uts_ns and linux_banner out to init/version-timestamp.c
from init/version.c
init_uts_ns and linux_banner contain UTS_VERSION. During the ordinary
directory descending, they are compiled with __weak and used to
determine if vmlinux needs relinking. Just before the vmlinux link,
they are compiled without __weak to embed the real version and
timestamp.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
31 lines
789 B
C
31 lines
789 B
C
// SPDX-License-Identifier: GPL-2.0-only
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#include <generated/compile.h>
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#include <generated/utsrelease.h>
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#include <linux/version.h>
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#include <linux/proc_ns.h>
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#include <linux/refcount.h>
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#include <linux/uts.h>
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#include <linux/utsname.h>
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struct uts_namespace init_uts_ns = {
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.ns.count = REFCOUNT_INIT(2),
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.name = {
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.sysname = UTS_SYSNAME,
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.nodename = UTS_NODENAME,
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.release = UTS_RELEASE,
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.version = UTS_VERSION,
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.machine = UTS_MACHINE,
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.domainname = UTS_DOMAINNAME,
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},
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.user_ns = &init_user_ns,
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.ns.inum = PROC_UTS_INIT_INO,
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#ifdef CONFIG_UTS_NS
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.ns.ops = &utsns_operations,
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#endif
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};
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/* FIXED STRINGS! Don't touch! */
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const char linux_banner[] =
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"Linux version " UTS_RELEASE " (" LINUX_COMPILE_BY "@"
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LINUX_COMPILE_HOST ") (" LINUX_COMPILER ") " UTS_VERSION "\n";
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