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Linux kernel for uConsole
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Fangrui Song 54530dd3be arm64: Delete the space separator in __emit_inst 
[ Upstream commit c9a4ef6645 ]

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 17:25:58 +02:00
arch arm64: Delete the space separator in __emit_inst 2020-05-02 17:25:58 +02:00
block block, bfq: fix use-after-free in bfq_idle_slice_timer_body 2020-04-17 10:48:42 +02:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto crypto: api - Fix race condition in crypto_spawn_alg 2020-02-11 04:34:05 -08:00
Documentation arm64: errata: Hide CTR_EL0.DIC on systems affected by Neoverse-N1 #1542419 2020-04-29 16:31:08 +02:00
drivers xen/xenbus: ensure xenbus_map_ring_valloc() returns proper grant status 2020-05-02 17:25:58 +02:00
firmware Fix built-in early-load Intel microcode alignment 2020-01-23 08:21:29 +01:00
fs xfs: fix partially uninitialized structure in xfs_reflink_remap_extent 2020-05-02 17:25:55 +02:00
include svcrdma: Fix leak of svc_rdma_recv_ctxt objects 2020-05-02 17:25:52 +02:00
init fork: fix some -Wmissing-prototypes warnings 2019-12-05 09:21:04 +01:00
ipc ipc/util.c: sysvipc_find_ipc() should increase position index 2020-04-29 16:31:13 +02:00
kernel perf/core: fix parent pid/tid in task exit events 2020-05-02 17:25:53 +02:00
lib lib/raid6: use vdupq_n_u8 to avoid endianness warnings 2020-04-23 10:30:15 +02:00
LICENSES LICENSES: Remove CC-BY-SA-4.0 license text 2018-10-18 11:28:50 +02:00
mm mm: shmem: disable interrupt when acquiring info->lock in userfaultfd_copy path 2020-05-02 17:25:54 +02:00
net svcrdma: Fix leak of svc_rdma_recv_ctxt objects 2020-05-02 17:25:52 +02:00
samples vmalloc: fix remap_vmalloc_range() bounds checks 2020-04-29 16:31:27 +02:00
scripts kconfig: qconf: Fix a few alignment issues 2020-04-29 16:31:13 +02:00
security KEYS: Avoid false positive ENOMEM error on key read 2020-04-29 16:31:23 +02:00
sound ALSA: hda: call runtime_allow() for all hda controllers 2020-05-02 17:25:58 +02:00
tools objtool: Support Clang non-section symbols in ORC dump 2020-05-02 17:25:57 +02:00
usr initramfs: restore default compression behavior 2020-04-13 10:44:59 +02:00
virt x86/kvm: Cache gfn to pfn translation 2020-04-29 16:31:19 +02:00
.clang-format clang-format: Set IndentWrappedFunctionNames false 2018-08-01 18:38:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap libnvdimm-for-4.19_misc 2018-08-25 18:13:10 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS 9p: remove Ron Minnich from MAINTAINERS 2018-08-17 16:20:26 -07:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS MAINTAINERS: Update drm/i915 bug filing URL 2020-02-28 16:38:49 +01:00
Makefile Linux 4.19.119 2020-04-29 16:31:35 +02:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -06:00

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.
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.