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Fangrui Song 1876e0e654 arm64: Delete the space separator in __emit_inst
[ Upstream commit c9a4ef66450145a356a626c833d3d7b1668b3ded ]

In assembly, many instances of __emit_inst(x) expand to a directive. In
a few places __emit_inst(x) is used as an assembler macro argument. For
example, in arch/arm64/kvm/hyp/entry.S

  ALTERNATIVE(nop, SET_PSTATE_PAN(1), ARM64_HAS_PAN, CONFIG_ARM64_PAN)

expands to the following by the C preprocessor:

  alternative_insn nop, .inst (0xd500401f | ((0) << 16 | (4) << 5) | ((!!1) << 8)), 4, 1

Both comma and space are separators, with an exception that content
inside a pair of parentheses/quotes is not split, so the clang
integrated assembler splits the arguments to:

   nop, .inst, (0xd500401f | ((0) << 16 | (4) << 5) | ((!!1) << 8)), 4, 1

GNU as preprocesses the input with do_scrub_chars(). Its arm64 backend
(along with many other non-x86 backends) sees:

  alternative_insn nop,.inst(0xd500401f|((0)<<16|(4)<<5)|((!!1)<<8)),4,1
  # .inst(...) is parsed as one argument

while its x86 backend sees:

  alternative_insn nop,.inst (0xd500401f|((0)<<16|(4)<<5)|((!!1)<<8)),4,1
  # The extra space before '(' makes the whole .inst (...) parsed as two arguments

The non-x86 backend's behavior is considered unintentional
(https://sourceware.org/bugzilla/show_bug.cgi?id=25750).
So drop the space separator inside `.inst (...)` to make the clang
integrated assembler work.

Suggested-by: Ilie Halip <ilie.halip@gmail.com>
Signed-off-by: Fangrui Song <maskray@google.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/939
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-05-02 08:48:58 +02:00
arch arm64: Delete the space separator in __emit_inst 2020-05-02 08:48:58 +02:00
block blk-iocost: Fix error on iocost_ioc_vrate_adj 2020-05-02 08:48:53 +02:00
certs
crypto crypto: rng - Fix a refcounting bug in crypto_rng_reset() 2020-04-17 10:50:16 +02:00
Documentation USB: hub: Revert commit bd0e6c9614 ("usb: hub: try old enumeration scheme first for high speed devices") 2020-04-29 16:33:14 +02:00
drivers net: stmmac: socfpga: Allow all RGMII modes 2020-05-02 08:48:57 +02:00
fs xfs: fix partially uninitialized structure in xfs_reflink_remap_extent 2020-05-02 08:48:56 +02:00
include blk-iocost: Fix error on iocost_ioc_vrate_adj 2020-05-02 08:48:53 +02:00
init printk: queue wake_up_klogd irq_work only if per-CPU areas are ready 2020-05-02 08:48:42 +02:00
ipc ipc/util.c: sysvipc_find_ipc() should increase position index 2020-04-29 16:33:00 +02:00
kernel signal: check sig before setting info in kill_pid_usb_asyncio 2020-05-02 08:48:55 +02:00
lib lib/raid6/test: fix build on distros whose /bin/sh is not bash 2020-04-29 16:33:00 +02:00
LICENSES
mm mm: shmem: disable interrupt when acquiring info->lock in userfaultfd_copy path 2020-05-02 08:48:54 +02:00
net mac80211: fix channel switch trigger from unknown mesh peer 2020-05-02 08:48:58 +02:00
samples vmalloc: fix remap_vmalloc_range() bounds checks 2020-04-29 16:33:14 +02:00
scripts kbuild: fix DT binding schema rule again to avoid needless rebuilds 2020-05-02 08:48:42 +02:00
security KEYS: Avoid false positive ENOMEM error on key read 2020-04-29 16:33:11 +02:00
sound ALSA: hda: call runtime_allow() for all hda controllers 2020-05-02 08:48:57 +02:00
tools objtool: Support Clang non-section symbols in ORC dump 2020-05-02 08:48:57 +02:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
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Makefile Linux 5.4.36 2020-04-29 16:33:25 +02:00
README

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.