WSL2-Linux-Kernel/Documentation
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
..
ABI Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2019-09-27 19:37:27 -07:00
EDID
PCI
RCU
accounting
admin-guide Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
arm
arm64
block
bpf
cdrom
core-api kernel-doc: core-api: include string.h into core-api 2019-09-25 17:51:39 -07:00
cpu-freq
crypto
dev-tools
devicetree Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-09-28 17:47:33 -07:00
doc-guide
driver-api
fault-injection
fb
features
filesystems add virtio-fs 2019-09-27 15:54:24 -07:00
firmware-guide
firmware_class
fpga
gpu
hid
hwmon
i2c
ia64
ide
iio
infiniband
input
ioctl
isdn
kbuild Modules updates for v5.4 2019-09-22 10:34:46 -07:00
kernel-hacking
leds
livepatch
locking
m68k
maintainer
media
mic
mips Main MIPS changes for v5.4: 2019-09-22 09:30:30 -07:00
misc-devices
netlabel
networking Documentation: Clarify trap's description 2019-09-27 20:33:19 +02:00
nios2
openrisc
parisc
pcmcia
power
powerpc
process Documentation/process update for 5.4-rc1 2019-09-29 19:52:52 -07:00
riscv
s390
scheduler
scsi
security Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2019-09-27 19:37:27 -07:00
sh
sound
sparc
sphinx
sphinx-static
spi
target
timers
trace
translations
usb
userspace-api
virt KVM/Hyper-V: Add new KVM capability KVM_CAP_HYPERV_DIRECT_TLBFLUSH 2019-09-24 13:37:13 +02:00
virtual
vm mm: treewide: clarify pgtable_page_{ctor,dtor}() naming 2019-09-26 10:10:44 -07:00
w1
watchdog linux-watchdog 5.4-rc1 tag 2019-09-27 11:17:38 -07:00
x86
xtensa
.gitignore
COPYING-logo
Changes
CodingStyle
DMA-API-HOWTO.txt
DMA-API.txt
DMA-ISA-LPC.txt
DMA-attributes.txt
IPMI.txt
IRQ-affinity.txt
IRQ-domain.txt
IRQ.txt
Kconfig
Makefile
SubmittingPatches
asm-annotations.rst linkage: Introduce new macros for assembler symbols 2019-10-18 09:48:11 +02:00
atomic_bitops.txt
atomic_t.txt
bus-virt-phys-mapping.txt
conf.py
crc32.txt
debugging-modules.txt
debugging-via-ohci1394.txt
digsig.txt
docutils.conf
dontdiff
futex-requeue-pi.txt
hwspinlock.txt
index.rst linkage: Introduce new macros for assembler symbols 2019-10-18 09:48:11 +02:00
io-mapping.txt
io_ordering.txt
irqflags-tracing.txt
kobject.txt
kprobes.txt
kref.txt
logo.gif
lzo.txt
mailbox.txt
memory-barriers.txt
nommu-mmap.txt
padata.txt
percpu-rw-semaphore.txt
pi-futex.txt
preempt-locking.txt
rbtree.txt
remoteproc.txt
robust-futex-ABI.txt
robust-futexes.txt
rpmsg.txt
speculation.txt
static-keys.txt
tee.txt
this_cpu_ops.txt
unaligned-memory-access.txt
xz.txt