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Ard Biesheuvel bc310baf2b x86/boot/compressed: Relax sed symbol type regex for LLVM ld.lld
The final build stage of the x86 kernel captures some symbol
addresses from the decompressor binary and copies them into zoffset.h.
It uses sed with a regular expression that matches the address, symbol
type and symbol name, and mangles the captured addresses and the names
of symbols of interest into #define directives that are added to
zoffset.h

The symbol type is indicated by a single letter, which we match
strictly: only letters in the set 'ABCDGRSTVW' are matched, even
though the actual symbol type is relevant and therefore ignored.

Commit bc7c9d620 ("efi/libstub/x86: Force 'hidden' visibility for
extern declarations") made a change to the way external symbol
references are classified, resulting in 'startup_32' now being
emitted as a hidden symbol. This prevents the use of GOT entries to
refer to this symbol via its absolute address, which recent toolchains
(including Clang based ones) already avoid by default, making this
change a no-op in the majority of cases.

However, as it turns out, the LLVM linker classifies such hidden
symbols as symbols with static linkage in fully linked ELF binaries,
causing tools such as NM to output a lowercase 't' rather than an upper
case 'T' for the type of such symbols. Since our sed expression only
matches upper case letters for the symbol type, the line describing
startup_32 is disregarded, resulting in a build error like the following

  arch/x86/boot/header.S:568:18: error: symbol 'ZO_startup_32' can not be
                                        undefined in a subtraction expression
  init_size: .long (0x00000000008fd000 - ZO_startup_32 +
                    (((0x0000000001f6361c + ((0x0000000001f6361c >> 8) + 65536)
                     - 0x00000000008c32e5) + 4095) & ~4095)) # kernel initialization size

Given that we are only interested in the value of the symbol, let's match
any character in the set 'a-zA-Z' instead.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
History 2020-01-20 08:14:29 +01:00
arch x86/boot/compressed: Relax sed symbol type regex for LLVM ld.lld 2020-01-20 08:14:29 +01:00
block block: fix an integer overflow in logical block size 2020-01-15 21:43:09 -07:00
certs certs: Add wrapper function to check blacklisted binary hash 2019-11-12 12:25:50 +11:00
crypto tpmdd fixes for Linux v5.5-rc3 2019-12-18 17:17:36 -08:00
Documentation efi/x86: Limit EFI old memory map to SGI UV machines 2020-01-20 08:13:01 +01:00
drivers efi: Fix handling of multiple efi_fake_mem= entries 2020-01-20 08:14:29 +01:00
fs io_uring-5.5-2020-01-16 2020-01-17 11:25:45 -08:00
include efi: Fix handling of multiple efi_fake_mem= entries 2020-01-20 08:14:29 +01:00
init mm, debug_pagealloc: don't rely on static keys too early 2020-01-13 18:19:02 -08:00
ipc treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-01-19 12:03:53 -08:00
lib lib/vdso: Make __cvdso_clock_getres() static 2020-01-10 19:29:01 +01:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm Linux 5.5-rc7 2020-01-20 08:05:16 +01:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-01-19 12:03:53 -08:00
samples samples/seccomp: Zero out members based on seccomp_notif_sizes 2020-01-02 13:03:39 -08:00
scripts Kbuild fixes for v5.5 (2nd) 2020-01-03 11:21:25 -08:00
security + Bug fixes 2020-01-04 19:28:30 -08:00
sound sound fixes for 5.5-rc7 2020-01-17 08:38:35 -08:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-01-19 12:03:53 -08:00
usr gen_initramfs_list.sh: fix 'bad variable name' error 2020-01-04 00:00:48 +09:00
virt PPC KVM fix for 5.5 2019-12-22 13:18:15 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore modpost: dump missing namespaces into a single modules.nsdeps file 2019-11-11 20:10:01 +09:00
.mailmap MAINTAINERS: update my email address 2020-01-11 14:33:39 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS Linux 5.4-rc4 2019-10-29 04:43:29 -06:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-01-19 12:03:53 -08:00
Makefile Linux 5.5-rc7 2020-01-19 16:02:49 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

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.