| Message ID | 20201109201826.120534-8-adhemerval.zanella@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Simplify internal Linux syscall | expand |
* Adhemerval Zanella via Libc-alpha: > The auto-generated syscalls calls the __syscall_error, and for i686 > it results in much less compat code: > > --- sizes-i686-linux-gnu.outline > +++ sizes-i686-linux-gnu.inline > text data bss dec hex filename > -1933727 11324 10172 1955223 1dd597 libc.so > - 175366 4768 184 180318 2c05e elf/ld.so > - 109851 832 8408 119091 1d133 nptl/libpthread.so > - 27983 628 184 28795 707b rt/librt.so > +1937875 11324 10172 1959371 1de5cb libc.so > + 175790 4768 184 180742 2c206 elf/ld.so > + 110179 832 8408 119419 1d27b nptl/libpthread.so > + 28139 628 184 28951 7117 rt/librt.so > > This patch enabled SYSCALL_ERROR_FUNC with the expected abi by also > defining SYSCALL_ERROR_FUNC_ATTR. Sorry, what do you mean with “compat code”? And does the code size go up or down with this change? Thanks, Florian
On 10/11/2020 09:49, Florian Weimer wrote: > * Adhemerval Zanella via Libc-alpha: > >> The auto-generated syscalls calls the __syscall_error, and for i686 >> it results in much less compat code: >> >> --- sizes-i686-linux-gnu.outline >> +++ sizes-i686-linux-gnu.inline >> text data bss dec hex filename >> -1933727 11324 10172 1955223 1dd597 libc.so >> - 175366 4768 184 180318 2c05e elf/ld.so >> - 109851 832 8408 119091 1d133 nptl/libpthread.so >> - 27983 628 184 28795 707b rt/librt.so >> +1937875 11324 10172 1959371 1de5cb libc.so >> + 175790 4768 184 180742 2c206 elf/ld.so >> + 110179 832 8408 119419 1d27b nptl/libpthread.so >> + 28139 628 184 28951 7117 rt/librt.so >> >> This patch enabled SYSCALL_ERROR_FUNC with the expected abi by also >> defining SYSCALL_ERROR_FUNC_ATTR. > > Sorry, what do you mean with “compat code”? And does the code size go > up or down with this change? I think I should have made it more clear in the patch description. This comparison only shows the code size difference between enabling or not SYSCALL_ERROR_FUNC for the architecture. It only affects the C implementations and by 'compat code' I meant code size. The code size difference for this *whole* patchset is show below, where 'before' is the code size output (in bytes) from 'size' binutils tools with prior the first patch of the set and 'after' with all patch applied. In general I see a small improvement in total code size. I think we might get some smalls improvement by changing the auto-generated assembly syscall to C implementations, it would allow to move from outline call to inline errno setting or vice-versa more easily. Architecture : before -> after : diff aarch64-linux-gnu ld.so : 138457 -> 138597 +0.10 libc.so : 1381655 -> 1381143 -0.04 libpthread.so : 99675 -> 98987 -0.69 librt.so : 24027 -> 23939 -0.37 alpha-linux-gnu ld.so : 171608 -> 171420 -0.11 libc.so : 1826396 -> 1825820 -0.03 libpthread.so : 127926 -> 126998 -0.73 librt.so : 32881 -> 32625 -0.78 arc-linux-gnuhf ld.so : 110037 -> 109617 -0.38 libc.so : 962368 -> 961226 -0.12 libpthread.so : 75403 -> 75463 +0.08 librt.so : 18794 -> 18704 -0.48 arm-linux-gnueabihf ld.so : 143219 -> 142755 -0.32 libc.so : 1266033 -> 1260285 -0.45 libpthread.so : 98075 -> 97335 -0.75 librt.so : 22756 -> 22516 -1.05 csky-linux-gnuabiv2 ld.so : 121194 -> 121410 +0.18 libc.so : 1202783 -> 1203475 +0.06 libpthread.so : 93140 -> 92756 -0.41 librt.so : 24727 -> 24935 +0.84 hppa-linux-gnu ld.so : 172095 -> 171887 -0.12 libc.so : 1567942 -> 1563690 -0.27 libpthread.so : 134371 -> 133235 -0.85 librt.so : 31613 -> 31221 -1.24 i686-linux-gnu ld.so : 175790 -> 175262 -0.30 libc.so : 1939247 -> 1933823 -0.28 libpthread.so : 110635 -> 109851 -0.71 librt.so : 28239 -> 27983 -0.91 ia64-linux-gnu ld.so : 293693 -> 293757 +0.02 libc.so : 2905590 -> 2905334 -0.01 libpthread.so : 206654 -> 205726 -0.45 librt.so : 47126 -> 46742 -0.81 m68k-linux-gnu ld.so : 118461 -> 118413 -0.04 libc.so : 1280292 -> 1274264 -0.47 libpthread.so : 87926 -> 86610 -1.50 librt.so : 24054 -> 23782 -1.13 microblaze-linux-gnu ld.so : 187304 -> 187480 +0.09 libc.so : 1835193 -> 1828161 -0.38 libpthread.so : 124416 -> 124048 -0.30 librt.so : 31028 -> 31032 +0.01 mips64-linux-gnu ld.so : 164336 -> 164208 -0.08 libc.so : 1707476 -> 1706700 -0.05 libpthread.so : 127189 -> 126341 -0.67 librt.so : 30543 -> 30252 -0.95 mips64-n32-linux-gnu ld.so : 158416 -> 158244 -0.11 libc.so : 1618530 -> 1616922 -0.10 libpthread.so : 119753 -> 118157 -1.33 librt.so : 29943 -> 29708 -0.78 mips-linux-gnu ld.so : 173488 -> 173316 -0.10 libc.so : 1645227 -> 1644619 -0.04 libpthread.so : 121321 -> 120945 -0.31 librt.so : 30837 -> 30822 -0.05 nios2-linux-gnu ld.so : 142874 -> 142974 +0.07 libc.so : 1417868 -> 1418012 +0.01 libpthread.so : 103026 -> 103026 +0.00 librt.so : 26472 -> 26412 -0.23 powerpc64le-linux-gnu ld.so : 204310 -> 204878 +0.28 libc.so : 2013898 -> 2016558 +0.13 libpthread.so : 139425 -> 138769 -0.47 librt.so : 31407 -> 31643 +0.75 powerpc64-linux-gnu ld.so : 204077 -> 204677 +0.29 libc.so : 2011449 -> 2014389 +0.15 libpthread.so : 154833 -> 154117 -0.46 librt.so : 36571 -> 36763 +0.53 powerpc-linux-gnu ld.so : 175973 -> 175117 -0.49 libc.so : 1780644 -> 1771572 -0.51 libpthread.so : 135547 -> 134231 -0.97 librt.so : 32271 -> 32115 -0.48 riscv32-linux-gnu-rv32imafdc-ilp32d ld.so : 98229 -> 98065 -0.17 libc.so : 974660 -> 973224 -0.15 libpthread.so : 70861 -> 71063 +0.29 librt.so : 17053 -> 17011 -0.25 riscv64-linux-gnu-rv64imafdc-lp64d ld.so : 98274 -> 98168 -0.11 libc.so : 1031904 -> 1030870 -0.10 libpthread.so : 76828 -> 76588 -0.31 librt.so : 18150 -> 18016 -0.74 s390-linux-gnu ld.so : 139947 -> 139835 -0.08 libc.so : 1581950 -> 1581034 -0.06 libpthread.so : 105734 -> 105194 -0.51 librt.so : 26981 -> 27065 +0.31 s390x-linux-gnu ld.so : 168697 -> 168561 -0.08 libc.so : 1757244 -> 1756108 -0.06 libpthread.so : 119026 -> 117906 -0.94 librt.so : 29735 -> 29527 -0.70 sh4-linux-gnu ld.so : 122532 -> 122500 -0.03 libc.so : 1244034 -> 1240914 -0.25 libpthread.so : 93172 -> 92808 -0.39 librt.so : 24042 -> 23746 -1.23 sparc64-linux-gnu ld.so : 152025 -> 151577 -0.29 libc.so : 1477340 -> 1472988 -0.29 libpthread.so : 103018 -> 101706 -1.27 librt.so : 27279 -> 27023 -0.94 sparcv9-linux-gnu ld.so : 151207 -> 150951 -0.17 libc.so : 1569967 -> 1563567 -0.41 libpthread.so : 102674 -> 101362 -1.28 librt.so : 26815 -> 26623 -0.72 x86_64-linux-gnu ld.so : 167435 -> 167451 +0.01 libc.so : 1774908 -> 1774348 -0.03 libpthread.so : 100013 -> 99261 -0.75 librt.so : 24935 -> 24751 -0.74 x86_64-linux-gnu-x32 ld.so : 163591 -> 163531 -0.04 libc.so : 1730210 -> 1729522 -0.04 libpthread.so : 93950 -> 93398 -0.59 librt.so : 21951 -> 21851 -0.46
diff --git a/sysdeps/unix/sysv/linux/i386/Makefile b/sysdeps/unix/sysv/linux/i386/Makefile index da716e2c1b..983b02e081 100644 --- a/sysdeps/unix/sysv/linux/i386/Makefile +++ b/sysdeps/unix/sysv/linux/i386/Makefile @@ -28,22 +28,9 @@ gen-as-const-headers += ucontext_i.sym endif ifeq ($(subdir),csu) -sysdep-dl-routines += sysdep ifeq (yes,$(build-shared)) sysdep_routines += divdi3 shared-only-routines += divdi3 CPPFLAGS-divdi3.c = -Din_divdi3_c endif endif - -ifeq ($(subdir),nptl) -# pull in __syscall_error routine -libpthread-routines += sysdep -libpthread-shared-only-routines += sysdep -endif - -ifeq ($(subdir),rt) -# pull in __syscall_error routine -librt-routines += sysdep -librt-shared-only-routines += sysdep -endif diff --git a/sysdeps/unix/sysv/linux/i386/sysdep.c b/sysdeps/unix/sysv/linux/i386/sysdep.c deleted file mode 100644 index e6228406dd..0000000000 --- a/sysdeps/unix/sysv/linux/i386/sysdep.c +++ /dev/null @@ -1,29 +0,0 @@ -/* Copyright (C) 2015-2020 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - <https://www.gnu.org/licenses/>. */ - -#include <errno.h> - -/* This routine is jumped to by all the syscall handlers, to stash - an error number into errno. ERROR is the negative error number - returned from the x86 kernel. */ -int -__attribute__ ((__regparm__ (1))) -__syscall_error (int error) -{ - __set_errno (-error); - return -1; -} diff --git a/sysdeps/unix/sysv/linux/i386/sysdep.h b/sysdeps/unix/sysv/linux/i386/sysdep.h index 4680013de4..977dc1ab42 100644 --- a/sysdeps/unix/sysv/linux/i386/sysdep.h +++ b/sysdeps/unix/sysv/linux/i386/sysdep.h @@ -19,6 +19,9 @@ #ifndef _LINUX_I386_SYSDEP_H #define _LINUX_I386_SYSDEP_H 1 +#define SYSCALL_ERROR_FUNC +#define SYSCALL_ERROR_FUNC_ATTR __attribute__ ((__regparm__ (1))) + /* There is some commonality. */ #include <sysdeps/unix/sysv/linux/sysdep.h> #include <sysdeps/unix/i386/sysdep.h>
The auto-generated syscalls calls the __syscall_error, and for i686 it results in much less compat code: --- sizes-i686-linux-gnu.outline +++ sizes-i686-linux-gnu.inline text data bss dec hex filename -1933727 11324 10172 1955223 1dd597 libc.so - 175366 4768 184 180318 2c05e elf/ld.so - 109851 832 8408 119091 1d133 nptl/libpthread.so - 27983 628 184 28795 707b rt/librt.so +1937875 11324 10172 1959371 1de5cb libc.so + 175790 4768 184 180742 2c206 elf/ld.so + 110179 832 8408 119419 1d27b nptl/libpthread.so + 28139 628 184 28951 7117 rt/librt.so This patch enabled SYSCALL_ERROR_FUNC with the expected abi by also defining SYSCALL_ERROR_FUNC_ATTR. Checked on i686-linux-gnu. --- sysdeps/unix/sysv/linux/i386/Makefile | 13 ------------ sysdeps/unix/sysv/linux/i386/sysdep.c | 29 --------------------------- sysdeps/unix/sysv/linux/i386/sysdep.h | 3 +++ 3 files changed, 3 insertions(+), 42 deletions(-) delete mode 100644 sysdeps/unix/sysv/linux/i386/sysdep.c