linux/Documentation/index.rst
Jiri Slaby ffedeeb780 linkage: Introduce new macros for assembler symbols
Introduce new C macros for annotations of functions and data in
assembly. There is a long-standing mess in macros like ENTRY, END,
ENDPROC and similar. They are used in different manners and sometimes
incorrectly.

So introduce macros with clear use to annotate assembly as follows:

a) Support macros for the ones below
   SYM_T_FUNC -- type used by assembler to mark functions
   SYM_T_OBJECT -- type used by assembler to mark data
   SYM_T_NONE -- type used by assembler to mark entries of unknown type

   They are defined as STT_FUNC, STT_OBJECT, and STT_NOTYPE
   respectively. According to the gas manual, this is the most portable
   way. I am not sure about other assemblers, so this can be switched
   back to %function and %object if this turns into a problem.
   Architectures can also override them by something like ", @function"
   if they need.

   SYM_A_ALIGN, SYM_A_NONE -- align the symbol?
   SYM_L_GLOBAL, SYM_L_WEAK, SYM_L_LOCAL -- linkage of symbols

b) Mostly internal annotations, used by the ones below
   SYM_ENTRY -- use only if you have to (for non-paired symbols)
   SYM_START -- use only if you have to (for paired symbols)
   SYM_END -- use only if you have to (for paired symbols)

c) Annotations for code
   SYM_INNER_LABEL_ALIGN -- only for labels in the middle of code
   SYM_INNER_LABEL -- only for labels in the middle of code

   SYM_FUNC_START_LOCAL_ALIAS -- use where there are two local names for
	one function
   SYM_FUNC_START_ALIAS -- use where there are two global names for one
	function
   SYM_FUNC_END_ALIAS -- the end of LOCAL_ALIASed or ALIASed function

   SYM_FUNC_START -- use for global functions
   SYM_FUNC_START_NOALIGN -- use for global functions, w/o alignment
   SYM_FUNC_START_LOCAL -- use for local functions
   SYM_FUNC_START_LOCAL_NOALIGN -- use for local functions, w/o
	alignment
   SYM_FUNC_START_WEAK -- use for weak functions
   SYM_FUNC_START_WEAK_NOALIGN -- use for weak functions, w/o alignment
   SYM_FUNC_END -- the end of SYM_FUNC_START_LOCAL, SYM_FUNC_START,
	SYM_FUNC_START_WEAK, ...

   For functions with special (non-C) calling conventions:
   SYM_CODE_START -- use for non-C (special) functions
   SYM_CODE_START_NOALIGN -- use for non-C (special) functions, w/o
	alignment
   SYM_CODE_START_LOCAL -- use for local non-C (special) functions
   SYM_CODE_START_LOCAL_NOALIGN -- use for local non-C (special)
	functions, w/o alignment
   SYM_CODE_END -- the end of SYM_CODE_START_LOCAL or SYM_CODE_START

d) For data
   SYM_DATA_START -- global data symbol
   SYM_DATA_START_LOCAL -- local data symbol
   SYM_DATA_END -- the end of the SYM_DATA_START symbol
   SYM_DATA_END_LABEL -- the labeled end of SYM_DATA_START symbol
   SYM_DATA -- start+end wrapper around simple global data
   SYM_DATA_LOCAL -- start+end wrapper around simple local data

==========

The macros allow to pair starts and ends of functions and mark functions
correctly in the output ELF objects.

All users of the old macros in x86 are converted to use these in further
patches.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-arch@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: x86-ml <x86@kernel.org>
Cc: xen-devel@lists.xenproject.org
Link: https://lkml.kernel.org/r/20191011115108.12392-2-jslaby@suse.cz
2019-10-18 09:48:11 +02:00

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.. The Linux Kernel documentation master file, created by
sphinx-quickstart on Fri Feb 12 13:51:46 2016.
You can adapt this file completely to your liking, but it should at least
contain the root `toctree` directive.
.. _linux_doc:
The Linux Kernel documentation
==============================
This is the top level of the kernel's documentation tree. Kernel
documentation, like the kernel itself, is very much a work in progress;
that is especially true as we work to integrate our many scattered
documents into a coherent whole. Please note that improvements to the
documentation are welcome; join the linux-doc list at vger.kernel.org if
you want to help out.
Licensing documentation
-----------------------
The following describes the license of the Linux kernel source code
(GPLv2), how to properly mark the license of individual files in the source
tree, as well as links to the full license text.
* :ref:`kernel_licensing`
User-oriented documentation
---------------------------
The following manuals are written for *users* of the kernel — those who are
trying to get it to work optimally on a given system.
.. toctree::
:maxdepth: 2
admin-guide/index
kbuild/index
Firmware-related documentation
------------------------------
The following holds information on the kernel's expectations regarding the
platform firmwares.
.. toctree::
:maxdepth: 2
firmware-guide/index
Application-developer documentation
-----------------------------------
The user-space API manual gathers together documents describing aspects of
the kernel interface as seen by application developers.
.. toctree::
:maxdepth: 2
userspace-api/index
ioctl/index
Introduction to kernel development
----------------------------------
These manuals contain overall information about how to develop the kernel.
The kernel community is quite large, with thousands of developers
contributing over the course of a year. As with any large community,
knowing how things are done will make the process of getting your changes
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.. toctree::
:maxdepth: 2
process/index
dev-tools/index
doc-guide/index
kernel-hacking/index
trace/index
maintainer/index
fault-injection/index
livepatch/index
Kernel API documentation
------------------------
These books get into the details of how specific kernel subsystems work
from the point of view of a kernel developer. Much of the information here
is taken directly from the kernel source, with supplemental material added
as needed (or at least as we managed to add it — probably *not* all that is
needed).
.. toctree::
:maxdepth: 2
driver-api/index
core-api/index
locking/index
accounting/index
block/index
cdrom/index
ide/index
fb/index
fpga/index
hid/index
i2c/index
iio/index
isdn/index
infiniband/index
leds/index
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sound/index
crypto/index
filesystems/index
vm/index
bpf/index
usb/index
PCI/index
misc-devices/index
mic/index
scheduler/index
Architecture-agnostic documentation
-----------------------------------
.. toctree::
:maxdepth: 2
asm-annotations
Architecture-specific documentation
-----------------------------------
These books provide programming details about architecture-specific
implementation.
.. toctree::
:maxdepth: 2
arm/index
arm64/index
ia64/index
m68k/index
mips/index
nios2/nios2
openrisc/index
parisc/index
powerpc/index
riscv/index
s390/index
sh/index
sparc/index
x86/index
xtensa/index
Filesystem Documentation
------------------------
The documentation in this section are provided by specific filesystem
subprojects.
.. toctree::
:maxdepth: 2
filesystems/ext4/index
Translations
------------
.. toctree::
:maxdepth: 2
translations/index
Indices and tables
==================
* :ref:`genindex`