* [PATCH 0/2] Remove some i386 system call optimizations
@ 2022-01-11 10:05 Florian Weimer
2022-01-11 10:06 ` [PATCH 1/2] i386: Always treat %ebx as an allocatable register Florian Weimer
` (2 more replies)
0 siblings, 3 replies; 14+ messages in thread
From: Florian Weimer @ 2022-01-11 10:05 UTC (permalink / raw)
To: libc-alpha; +Cc: Jakub Jelinek, H.J. Lu
The configure check for CAN_USE_REGISTER_ASM_EBP is unreliable. And we
used it to switch away from using %ebx in assembler constraints, but
this appears to be no longer necessary.
Tested on i686-linux-gnu. Built with build-many-glibcs.py.
Thanks,
Florian
Florian Weimer (2):
i386: Always treat %ebx as an allocatable register
i386: Always use __libc_do_syscall for 6-argument syscalls (bug 27997)
config.h.in | 4 -
sysdeps/unix/sysv/linux/i386/configure | 39 ----
sysdeps/unix/sysv/linux/i386/configure.ac | 17 --
sysdeps/unix/sysv/linux/i386/sysdep.h | 222 +++-------------------
4 files changed, 27 insertions(+), 255 deletions(-)
base-commit: e72ef23ee88187284b4b1ca9b2e314e618429d35
--
2.34.1
^ permalink raw reply [flat|nested] 14+ messages in thread* [PATCH 1/2] i386: Always treat %ebx as an allocatable register 2022-01-11 10:05 [PATCH 0/2] Remove some i386 system call optimizations Florian Weimer @ 2022-01-11 10:06 ` Florian Weimer 2022-01-11 10:06 ` [PATCH 2/2] i386: Always use __libc_do_syscall for 6-argument syscalls (bug 27997) Florian Weimer 2022-01-11 14:00 ` [PATCH 0/2] Remove some i386 system call optimizations H.J. Lu 2 siblings, 0 replies; 14+ messages in thread From: Florian Weimer @ 2022-01-11 10:06 UTC (permalink / raw) To: libc-alpha; +Cc: Jakub Jelinek, H.J. Lu !CAN_USE_REGISTER_ASM_EBP also disables the direct use of %ebx in system calls, but that is not actually needed anymore. --- sysdeps/unix/sysv/linux/i386/sysdep.h | 192 ++++---------------------- 1 file changed, 25 insertions(+), 167 deletions(-) diff --git a/sysdeps/unix/sysv/linux/i386/sysdep.h b/sysdeps/unix/sysv/linux/i386/sysdep.h index 66c2833a49..fcd78e3157 100644 --- a/sysdeps/unix/sysv/linux/i386/sysdep.h +++ b/sysdeps/unix/sysv/linux/i386/sysdep.h @@ -239,35 +239,6 @@ extern int __syscall_error (int) attribute_hidden __attribute__ ((__regparm__ (1))); #ifndef OPTIMIZE_FOR_GCC_5 -/* We need some help from the assembler to generate optimal code. We - define some macros here which later will be used. */ -asm (".L__X'%ebx = 1\n\t" - ".L__X'%ecx = 2\n\t" - ".L__X'%edx = 2\n\t" - ".L__X'%eax = 3\n\t" - ".L__X'%esi = 3\n\t" - ".L__X'%edi = 3\n\t" - ".L__X'%ebp = 3\n\t" - ".L__X'%esp = 3\n\t" - ".macro bpushl name reg\n\t" - ".if 1 - \\name\n\t" - ".if 2 - \\name\n\t" - "error\n\t" - ".else\n\t" - "xchgl \\reg, %ebx\n\t" - ".endif\n\t" - ".endif\n\t" - ".endm\n\t" - ".macro bpopl name reg\n\t" - ".if 1 - \\name\n\t" - ".if 2 - \\name\n\t" - "error\n\t" - ".else\n\t" - "xchgl \\reg, %ebx\n\t" - ".endif\n\t" - ".endif\n\t" - ".endm\n\t"); - /* Six-argument syscalls use an out-of-line helper, because an inline asm using all registers apart from %esp cannot work reliably and the assembler does not support describing an asm that saves and @@ -379,187 +350,74 @@ struct libc_do_syscall_args (int) resultvar; }) #if I386_USE_SYSENTER -# ifdef OPTIMIZE_FOR_GCC_5 -# ifdef PIC -# define INTERNAL_SYSCALL_MAIN_INLINE(name, nr, args...) \ +# ifdef PIC +# define INTERNAL_SYSCALL_MAIN_INLINE(name, nr, args...) \ LOADREGS_##nr(args) \ asm volatile ( \ "call *%%gs:%P2" \ : "=a" (resultvar) \ : "a" (__NR_##name), "i" (offsetof (tcbhead_t, sysinfo)) \ ASMARGS_##nr(args) : "memory", "cc") -# define INTERNAL_SYSCALL_MAIN_NCS(name, nr, args...) \ +# define INTERNAL_SYSCALL_MAIN_NCS(name, nr, args...) \ LOADREGS_##nr(args) \ asm volatile ( \ "call *%%gs:%P2" \ : "=a" (resultvar) \ : "a" (name), "i" (offsetof (tcbhead_t, sysinfo)) \ ASMARGS_##nr(args) : "memory", "cc") -# else -# define INTERNAL_SYSCALL_MAIN_INLINE(name, nr, args...) \ +# else /* I386_USE_SYSENTER && !PIC */ +# define INTERNAL_SYSCALL_MAIN_INLINE(name, nr, args...) \ LOADREGS_##nr(args) \ asm volatile ( \ "call *_dl_sysinfo" \ : "=a" (resultvar) \ : "a" (__NR_##name) ASMARGS_##nr(args) : "memory", "cc") -# define INTERNAL_SYSCALL_MAIN_NCS(name, nr, args...) \ +# define INTERNAL_SYSCALL_MAIN_NCS(name, nr, args...) \ LOADREGS_##nr(args) \ asm volatile ( \ "call *_dl_sysinfo" \ : "=a" (resultvar) \ : "a" (name) ASMARGS_##nr(args) : "memory", "cc") -# endif -# else /* GCC 5 */ -# ifdef PIC -# define INTERNAL_SYSCALL_MAIN_INLINE(name, nr, args...) \ - EXTRAVAR_##nr \ - asm volatile ( \ - LOADARGS_##nr \ - "movl %1, %%eax\n\t" \ - "call *%%gs:%P2\n\t" \ - RESTOREARGS_##nr \ - : "=a" (resultvar) \ - : "i" (__NR_##name), "i" (offsetof (tcbhead_t, sysinfo)) \ - ASMFMT_##nr(args) : "memory", "cc") -# define INTERNAL_SYSCALL_MAIN_NCS(name, nr, args...) \ - EXTRAVAR_##nr \ - asm volatile ( \ - LOADARGS_##nr \ - "call *%%gs:%P2\n\t" \ - RESTOREARGS_##nr \ - : "=a" (resultvar) \ - : "0" (name), "i" (offsetof (tcbhead_t, sysinfo)) \ - ASMFMT_##nr(args) : "memory", "cc") -# else -# define INTERNAL_SYSCALL_MAIN_INLINE(name, nr, args...) \ - EXTRAVAR_##nr \ - asm volatile ( \ - LOADARGS_##nr \ - "movl %1, %%eax\n\t" \ - "call *_dl_sysinfo\n\t" \ - RESTOREARGS_##nr \ - : "=a" (resultvar) \ - : "i" (__NR_##name) ASMFMT_##nr(args) : "memory", "cc") -# define INTERNAL_SYSCALL_MAIN_NCS(name, nr, args...) \ - EXTRAVAR_##nr \ - asm volatile ( \ - LOADARGS_##nr \ - "call *_dl_sysinfo\n\t" \ - RESTOREARGS_##nr \ - : "=a" (resultvar) \ - : "0" (name) ASMFMT_##nr(args) : "memory", "cc") -# endif -# endif /* GCC 5 */ -#else -# ifdef OPTIMIZE_FOR_GCC_5 -# define INTERNAL_SYSCALL_MAIN_INLINE(name, nr, args...) \ +# endif /* I386_USE_SYSENTER && !PIC */ +#else /* !I386_USE_SYSENTER */ +# define INTERNAL_SYSCALL_MAIN_INLINE(name, nr, args...) \ LOADREGS_##nr(args) \ asm volatile ( \ "int $0x80" \ : "=a" (resultvar) \ : "a" (__NR_##name) ASMARGS_##nr(args) : "memory", "cc") -# define INTERNAL_SYSCALL_MAIN_NCS(name, nr, args...) \ +# define INTERNAL_SYSCALL_MAIN_NCS(name, nr, args...) \ LOADREGS_##nr(args) \ asm volatile ( \ "int $0x80" \ : "=a" (resultvar) \ : "a" (name) ASMARGS_##nr(args) : "memory", "cc") -# else /* GCC 5 */ -# define INTERNAL_SYSCALL_MAIN_INLINE(name, nr, args...) \ - EXTRAVAR_##nr \ - asm volatile ( \ - LOADARGS_##nr \ - "movl %1, %%eax\n\t" \ - "int $0x80\n\t" \ - RESTOREARGS_##nr \ - : "=a" (resultvar) \ - : "i" (__NR_##name) ASMFMT_##nr(args) : "memory", "cc") -# define INTERNAL_SYSCALL_MAIN_NCS(name, nr, args...) \ - EXTRAVAR_##nr \ - asm volatile ( \ - LOADARGS_##nr \ - "int $0x80\n\t" \ - RESTOREARGS_##nr \ - : "=a" (resultvar) \ - : "0" (name) ASMFMT_##nr(args) : "memory", "cc") -# endif /* GCC 5 */ -#endif +#endif /* !I386_USE_SYSENTER */ -#define LOADARGS_0 -#ifdef __PIC__ -# if I386_USE_SYSENTER && defined PIC -# define LOADARGS_1 \ - "bpushl .L__X'%k3, %k3\n\t" -# define LOADARGS_5 \ - "movl %%ebx, %4\n\t" \ - "movl %3, %%ebx\n\t" -# else -# define LOADARGS_1 \ - "bpushl .L__X'%k2, %k2\n\t" -# define LOADARGS_5 \ - "movl %%ebx, %3\n\t" \ - "movl %2, %%ebx\n\t" -# endif -# define LOADARGS_2 LOADARGS_1 -# define LOADARGS_3 \ - "xchgl %%ebx, %%edi\n\t" -# define LOADARGS_4 LOADARGS_3 -#else -# define LOADARGS_1 -# define LOADARGS_2 -# define LOADARGS_3 -# define LOADARGS_4 -# define LOADARGS_5 -#endif - -#define RESTOREARGS_0 -#ifdef __PIC__ -# if I386_USE_SYSENTER && defined PIC -# define RESTOREARGS_1 \ - "bpopl .L__X'%k3, %k3\n\t" -# define RESTOREARGS_5 \ - "movl %4, %%ebx" -# else -# define RESTOREARGS_1 \ - "bpopl .L__X'%k2, %k2\n\t" -# define RESTOREARGS_5 \ - "movl %3, %%ebx" -# endif -# define RESTOREARGS_2 RESTOREARGS_1 -# define RESTOREARGS_3 \ - "xchgl %%edi, %%ebx\n\t" -# define RESTOREARGS_4 RESTOREARGS_3 -#else -# define RESTOREARGS_1 -# define RESTOREARGS_2 -# define RESTOREARGS_3 -# define RESTOREARGS_4 -# define RESTOREARGS_5 -#endif - -#ifdef OPTIMIZE_FOR_GCC_5 -# define LOADREGS_0() -# define ASMARGS_0() -# define LOADREGS_1(arg1) \ +#define LOADREGS_0() +#define ASMARGS_0() +#define LOADREGS_1(arg1) \ LOADREGS_0 () -# define ASMARGS_1(arg1) \ +#define ASMARGS_1(arg1) \ ASMARGS_0 (), "b" ((unsigned int) (arg1)) -# define LOADREGS_2(arg1, arg2) \ +#define LOADREGS_2(arg1, arg2) \ LOADREGS_1 (arg1) -# define ASMARGS_2(arg1, arg2) \ +#define ASMARGS_2(arg1, arg2) \ ASMARGS_1 (arg1), "c" ((unsigned int) (arg2)) -# define LOADREGS_3(arg1, arg2, arg3) \ +#define LOADREGS_3(arg1, arg2, arg3) \ LOADREGS_2 (arg1, arg2) -# define ASMARGS_3(arg1, arg2, arg3) \ +#define ASMARGS_3(arg1, arg2, arg3) \ ASMARGS_2 (arg1, arg2), "d" ((unsigned int) (arg3)) -# define LOADREGS_4(arg1, arg2, arg3, arg4) \ +#define LOADREGS_4(arg1, arg2, arg3, arg4) \ LOADREGS_3 (arg1, arg2, arg3) -# define ASMARGS_4(arg1, arg2, arg3, arg4) \ +#define ASMARGS_4(arg1, arg2, arg3, arg4) \ ASMARGS_3 (arg1, arg2, arg3), "S" ((unsigned int) (arg4)) -# define LOADREGS_5(arg1, arg2, arg3, arg4, arg5) \ +#define LOADREGS_5(arg1, arg2, arg3, arg4, arg5) \ LOADREGS_4 (arg1, arg2, arg3, arg4) -# define ASMARGS_5(arg1, arg2, arg3, arg4, arg5) \ +#define ASMARGS_5(arg1, arg2, arg3, arg4, arg5) \ ASMARGS_4 (arg1, arg2, arg3, arg4), "D" ((unsigned int) (arg5)) + +#ifdef OPTIMIZE_FOR_GCC_5 # define LOADREGS_6(arg1, arg2, arg3, arg4, arg5, arg6) \ register unsigned int _a6 asm ("ebp") = (unsigned int) (arg6); \ LOADREGS_5 (arg1, arg2, arg3, arg4, arg5) -- 2.34.1 ^ permalink raw reply [flat|nested] 14+ messages in thread
* [PATCH 2/2] i386: Always use __libc_do_syscall for 6-argument syscalls (bug 27997) 2022-01-11 10:05 [PATCH 0/2] Remove some i386 system call optimizations Florian Weimer 2022-01-11 10:06 ` [PATCH 1/2] i386: Always treat %ebx as an allocatable register Florian Weimer @ 2022-01-11 10:06 ` Florian Weimer 2022-01-11 14:00 ` [PATCH 0/2] Remove some i386 system call optimizations H.J. Lu 2 siblings, 0 replies; 14+ messages in thread From: Florian Weimer @ 2022-01-11 10:06 UTC (permalink / raw) To: libc-alpha; +Cc: Jakub Jelinek, H.J. Lu The CAN_USE_REGISTER_ASM_EBP optimization was unreliable because the configure-time check did not match how %ebp was used during the build. With GCC 12, autovectorization at -O2, and the need for -mstackrealign for compatibility with legacy binaries, the check is increasingly problematic: CAN_USE_REGISTER_ASM_EBP is set to 1, but glibc cannot be built with this optimization. --- config.h.in | 4 --- sysdeps/unix/sysv/linux/i386/configure | 39 ----------------------- sysdeps/unix/sysv/linux/i386/configure.ac | 17 ---------- sysdeps/unix/sysv/linux/i386/sysdep.h | 34 +++----------------- 4 files changed, 4 insertions(+), 90 deletions(-) diff --git a/config.h.in b/config.h.in index 82ade1cec4..ff8597413d 100644 --- a/config.h.in +++ b/config.h.in @@ -277,10 +277,6 @@ /* Define if static PIE is enabled. */ #define ENABLE_STATIC_PIE 0 -/* Some compiler options may now allow to use ebp in __asm__ (used mainly - in i386 6 argument syscall issue). */ -#define CAN_USE_REGISTER_ASM_EBP 0 - /* The default value of x86 CET control. */ #define DEFAULT_DL_X86_CET_CONTROL cet_elf_property diff --git a/sysdeps/unix/sysv/linux/i386/configure b/sysdeps/unix/sysv/linux/i386/configure index 0327590486..f119e62fc3 100644 --- a/sysdeps/unix/sysv/linux/i386/configure +++ b/sysdeps/unix/sysv/linux/i386/configure @@ -1,44 +1,5 @@ # This file is generated from configure.ac by Autoconf. DO NOT EDIT! # Local configure fragment for sysdeps/unix/sysv/linux/i386. -# Check if CFLAGS allows compiler to use ebp register in inline assembly. - -{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if compiler flags allows ebp in inline assembly" >&5 -$as_echo_n "checking if compiler flags allows ebp in inline assembly... " >&6; } -if ${libc_cv_can_use_register_asm_ebp+:} false; then : - $as_echo_n "(cached) " >&6 -else - -cat confdefs.h - <<_ACEOF >conftest.$ac_ext -/* end confdefs.h. */ - - void foo (int i) - { - register int reg asm ("ebp") = i; - asm ("# %0" : : "r" (reg)); - } -int -main () -{ - - ; - return 0; -} -_ACEOF -if ac_fn_c_try_compile "$LINENO"; then : - libc_cv_can_use_register_asm_ebp=yes -else - libc_cv_can_use_register_asm_ebp=no -fi -rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext - -fi -{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_can_use_register_asm_ebp" >&5 -$as_echo "$libc_cv_can_use_register_asm_ebp" >&6; } -if test $libc_cv_can_use_register_asm_ebp = yes; then - $as_echo "#define CAN_USE_REGISTER_ASM_EBP 1" >>confdefs.h - -fi - libc_cv_gcc_unwind_find_fde=yes ldd_rewrite_script=sysdeps/unix/sysv/linux/ldd-rewrite.sed diff --git a/sysdeps/unix/sysv/linux/i386/configure.ac b/sysdeps/unix/sysv/linux/i386/configure.ac index 9e980784bb..64ab2cc2c8 100644 --- a/sysdeps/unix/sysv/linux/i386/configure.ac +++ b/sysdeps/unix/sysv/linux/i386/configure.ac @@ -1,22 +1,5 @@ GLIBC_PROVIDES dnl See aclocal.m4 in the top level source directory. # Local configure fragment for sysdeps/unix/sysv/linux/i386. -# Check if CFLAGS allows compiler to use ebp register in inline assembly. -AC_CACHE_CHECK([if compiler flags allows ebp in inline assembly], - libc_cv_can_use_register_asm_ebp, [ -AC_COMPILE_IFELSE( - [AC_LANG_PROGRAM([ - void foo (int i) - { - register int reg asm ("ebp") = i; - asm ("# %0" : : "r" (reg)); - }])], - [libc_cv_can_use_register_asm_ebp=yes], - [libc_cv_can_use_register_asm_ebp=no]) -]) -if test $libc_cv_can_use_register_asm_ebp = yes; then - AC_DEFINE(CAN_USE_REGISTER_ASM_EBP) -fi - libc_cv_gcc_unwind_find_fde=yes ldd_rewrite_script=sysdeps/unix/sysv/linux/ldd-rewrite.sed diff --git a/sysdeps/unix/sysv/linux/i386/sysdep.h b/sysdeps/unix/sysv/linux/i386/sysdep.h index fcd78e3157..4558ab66cb 100644 --- a/sysdeps/unix/sysv/linux/i386/sysdep.h +++ b/sysdeps/unix/sysv/linux/i386/sysdep.h @@ -42,15 +42,6 @@ # endif #endif -/* Since GCC 5 and above can properly spill %ebx with PIC when needed, - we can inline syscalls with 6 arguments if GCC 5 or above is used - to compile glibc. Disable GCC 5 optimization when compiling for - profiling or when -fno-omit-frame-pointer is used since asm ("ebp") - can't be used to put the 6th argument in %ebp for syscall. */ -#if !defined PROF && CAN_USE_REGISTER_ASM_EBP -# define OPTIMIZE_FOR_GCC_5 -#endif - #ifdef __ASSEMBLER__ /* Linux uses a negative return value to indicate syscall errors, @@ -238,7 +229,6 @@ extern int __syscall_error (int) attribute_hidden __attribute__ ((__regparm__ (1))); -#ifndef OPTIMIZE_FOR_GCC_5 /* Six-argument syscalls use an out-of-line helper, because an inline asm using all registers apart from %esp cannot work reliably and the assembler does not support describing an asm that saves and @@ -249,7 +239,6 @@ struct libc_do_syscall_args { int ebx, edi, ebp; }; -#endif # define VDSO_NAME "LINUX_2.6" # define VDSO_HASH 61765110 @@ -302,14 +291,8 @@ struct libc_do_syscall_args /* Each object using 6-argument inline syscalls must include a definition of __libc_do_syscall. */ -#ifdef OPTIMIZE_FOR_GCC_5 -# define INTERNAL_SYSCALL_MAIN_6(name, args...) \ - INTERNAL_SYSCALL_MAIN_INLINE(name, 6, args) -# define INTERNAL_SYSCALL_MAIN_NCS_6(name, args...) \ - INTERNAL_SYSCALL_MAIN_NCS(name, 6, args) -#else /* GCC 5 */ -# define INTERNAL_SYSCALL_MAIN_6(name, arg1, arg2, arg3, \ - arg4, arg5, arg6) \ +#define INTERNAL_SYSCALL_MAIN_6(name, arg1, arg2, arg3, \ + arg4, arg5, arg6) \ struct libc_do_syscall_args _xv = \ { \ (int) (arg1), \ @@ -322,8 +305,8 @@ struct libc_do_syscall_args : "=a" (resultvar) \ : "i" (__NR_##name), "c" (arg2), "d" (arg3), "S" (arg4), "D" (&_xv) \ : "memory", "cc") -# define INTERNAL_SYSCALL_MAIN_NCS_6(name, arg1, arg2, arg3, \ - arg4, arg5, arg6) \ +#define INTERNAL_SYSCALL_MAIN_NCS_6(name, arg1, arg2, arg3, \ + arg4, arg5, arg6) \ struct libc_do_syscall_args _xv = \ { \ (int) (arg1), \ @@ -336,7 +319,6 @@ struct libc_do_syscall_args : "=a" (resultvar) \ : "a" (name), "c" (arg2), "d" (arg3), "S" (arg4), "D" (&_xv) \ : "memory", "cc") -#endif /* GCC 5 */ #define INTERNAL_SYSCALL(name, nr, args...) \ ({ \ @@ -417,14 +399,6 @@ struct libc_do_syscall_args #define ASMARGS_5(arg1, arg2, arg3, arg4, arg5) \ ASMARGS_4 (arg1, arg2, arg3, arg4), "D" ((unsigned int) (arg5)) -#ifdef OPTIMIZE_FOR_GCC_5 -# define LOADREGS_6(arg1, arg2, arg3, arg4, arg5, arg6) \ - register unsigned int _a6 asm ("ebp") = (unsigned int) (arg6); \ - LOADREGS_5 (arg1, arg2, arg3, arg4, arg5) -# define ASMARGS_6(arg1, arg2, arg3, arg4, arg5, arg6) \ - ASMARGS_5 (arg1, arg2, arg3, arg4, arg5), "r" (_a6) -#endif /* GCC 5 */ - #define ASMFMT_0() #ifdef __PIC__ # define ASMFMT_1(arg1) \ -- 2.34.1 ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 0/2] Remove some i386 system call optimizations 2022-01-11 10:05 [PATCH 0/2] Remove some i386 system call optimizations Florian Weimer 2022-01-11 10:06 ` [PATCH 1/2] i386: Always treat %ebx as an allocatable register Florian Weimer 2022-01-11 10:06 ` [PATCH 2/2] i386: Always use __libc_do_syscall for 6-argument syscalls (bug 27997) Florian Weimer @ 2022-01-11 14:00 ` H.J. Lu 2022-01-11 20:30 ` H.J. Lu 2 siblings, 1 reply; 14+ messages in thread From: H.J. Lu @ 2022-01-11 14:00 UTC (permalink / raw) To: Florian Weimer; +Cc: GNU C Library, Jakub Jelinek On Tue, Jan 11, 2022 at 2:05 AM Florian Weimer <fweimer@redhat.com> wrote: > > The configure check for CAN_USE_REGISTER_ASM_EBP is unreliable. And we > used it to switch away from using %ebx in assembler constraints, but > this appears to be no longer necessary. This GCC bug has been fixed in GCC 5 as seen in commit 021478683cc091de9902d297a7b161f8343ffb6a Author: Uros Bizjak <uros@gcc.gnu.org> Date: Fri Oct 17 08:00:58 2014 +0200 cpuid.h (__cpuid): Remove definitions that handle %ebx register in a special way. * config/i386/cpuid.h (__cpuid): Remove definitions that handle %ebx register in a special way. (__cpuid_count): Ditto. * config/i386/driver-i386.h: Protect with "#if defined(__GNUC__) && (__GNUC__ >= 5 || !defined(__PIC__))". (host_detect_local_cpu): Mention that GCC with non-fixed %ebx is required to compile the function. From-SVN: r216362 Since GCC 6.2 or above is required to build glibc, please remove the !OPTIMIZE_FOR_GCC_5 path and this issue will be resolved automatically. > Tested on i686-linux-gnu. Built with build-many-glibcs.py. > > Thanks, > Florian > > Florian Weimer (2): > i386: Always treat %ebx as an allocatable register > i386: Always use __libc_do_syscall for 6-argument syscalls (bug 27997) > > config.h.in | 4 - > sysdeps/unix/sysv/linux/i386/configure | 39 ---- > sysdeps/unix/sysv/linux/i386/configure.ac | 17 -- > sysdeps/unix/sysv/linux/i386/sysdep.h | 222 +++------------------- > 4 files changed, 27 insertions(+), 255 deletions(-) > > > base-commit: e72ef23ee88187284b4b1ca9b2e314e618429d35 > -- > 2.34.1 > -- H.J. ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 0/2] Remove some i386 system call optimizations 2022-01-11 14:00 ` [PATCH 0/2] Remove some i386 system call optimizations H.J. Lu @ 2022-01-11 20:30 ` H.J. Lu 2022-01-11 20:37 ` Florian Weimer 0 siblings, 1 reply; 14+ messages in thread From: H.J. Lu @ 2022-01-11 20:30 UTC (permalink / raw) To: Florian Weimer; +Cc: GNU C Library, Jakub Jelinek On Tue, Jan 11, 2022 at 6:00 AM H.J. Lu <hjl.tools@gmail.com> wrote: > > On Tue, Jan 11, 2022 at 2:05 AM Florian Weimer <fweimer@redhat.com> wrote: > > > > The configure check for CAN_USE_REGISTER_ASM_EBP is unreliable. And we > > used it to switch away from using %ebx in assembler constraints, but > > this appears to be no longer necessary. > > This GCC bug has been fixed in GCC 5 as seen in > > commit 021478683cc091de9902d297a7b161f8343ffb6a > Author: Uros Bizjak <uros@gcc.gnu.org> > Date: Fri Oct 17 08:00:58 2014 +0200 > > cpuid.h (__cpuid): Remove definitions that handle %ebx register in > a special way. > > * config/i386/cpuid.h (__cpuid): Remove definitions that handle %ebx > register in a special way. > (__cpuid_count): Ditto. > * config/i386/driver-i386.h: Protect with > "#if defined(__GNUC__) && (__GNUC__ >= 5 || !defined(__PIC__))". > (host_detect_local_cpu): Mention that GCC with non-fixed %ebx > is required to compile the function. > > From-SVN: r216362 > > Since GCC 6.2 or above is required to build glibc, please > remove the !OPTIMIZE_FOR_GCC_5 path and this issue > will be resolved automatically. There are /* Since GCC 5 and above can properly spill %ebx with PIC when needed, we can inline syscalls with 6 arguments if GCC 5 or above is used to compile glibc. Disable GCC 5 optimization when compiling for profiling or when -fno-omit-frame-pointer is used since asm ("ebp") can't be used to put the 6th argument in %ebp for syscall. */ #if !defined PROF && CAN_USE_REGISTER_ASM_EBP # define OPTIMIZE_FOR_GCC_5 #endif If we want to support profiling or -fno-omit-frame-pointer, we need to keep these codes. > > Tested on i686-linux-gnu. Built with build-many-glibcs.py. > > > > Thanks, > > Florian > > > > Florian Weimer (2): > > i386: Always treat %ebx as an allocatable register > > i386: Always use __libc_do_syscall for 6-argument syscalls (bug 27997) > > > > config.h.in | 4 - > > sysdeps/unix/sysv/linux/i386/configure | 39 ---- > > sysdeps/unix/sysv/linux/i386/configure.ac | 17 -- > > sysdeps/unix/sysv/linux/i386/sysdep.h | 222 +++------------------- > > 4 files changed, 27 insertions(+), 255 deletions(-) > > > > > > base-commit: e72ef23ee88187284b4b1ca9b2e314e618429d35 > > -- > > 2.34.1 > > > > > -- > H.J. -- H.J. ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 0/2] Remove some i386 system call optimizations 2022-01-11 20:30 ` H.J. Lu @ 2022-01-11 20:37 ` Florian Weimer 2022-01-11 22:20 ` H.J. Lu 0 siblings, 1 reply; 14+ messages in thread From: Florian Weimer @ 2022-01-11 20:37 UTC (permalink / raw) To: H.J. Lu; +Cc: GNU C Library, Jakub Jelinek * H. J. Lu: > On Tue, Jan 11, 2022 at 6:00 AM H.J. Lu <hjl.tools@gmail.com> wrote: >> >> On Tue, Jan 11, 2022 at 2:05 AM Florian Weimer <fweimer@redhat.com> wrote: >> > >> > The configure check for CAN_USE_REGISTER_ASM_EBP is unreliable. And we >> > used it to switch away from using %ebx in assembler constraints, but >> > this appears to be no longer necessary. >> >> This GCC bug has been fixed in GCC 5 as seen in >> >> commit 021478683cc091de9902d297a7b161f8343ffb6a >> Author: Uros Bizjak <uros@gcc.gnu.org> >> Date: Fri Oct 17 08:00:58 2014 +0200 >> >> cpuid.h (__cpuid): Remove definitions that handle %ebx register in >> a special way. >> >> * config/i386/cpuid.h (__cpuid): Remove definitions that handle %ebx >> register in a special way. >> (__cpuid_count): Ditto. >> * config/i386/driver-i386.h: Protect with >> "#if defined(__GNUC__) && (__GNUC__ >= 5 || !defined(__PIC__))". >> (host_detect_local_cpu): Mention that GCC with non-fixed %ebx >> is required to compile the function. >> >> From-SVN: r216362 >> >> Since GCC 6.2 or above is required to build glibc, please >> remove the !OPTIMIZE_FOR_GCC_5 path and this issue >> will be resolved automatically. > > There are > > /* Since GCC 5 and above can properly spill %ebx with PIC when needed, > we can inline syscalls with 6 arguments if GCC 5 or above is used > to compile glibc. Disable GCC 5 optimization when compiling for > profiling or when -fno-omit-frame-pointer is used since asm ("ebp") > can't be used to put the 6th argument in %ebp for syscall. */ > #if !defined PROF && CAN_USE_REGISTER_ASM_EBP > # define OPTIMIZE_FOR_GCC_5 > #endif > > If we want to support profiling or -fno-omit-frame-pointer, > we need to keep these codes. This is strictly for %ebp, I think, as indicated by the comment. %ebx does not need to be special-cased for profiling. I assume that building glibc (with profiling) is proof enough that this works? Thanks, Florian ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 0/2] Remove some i386 system call optimizations 2022-01-11 20:37 ` Florian Weimer @ 2022-01-11 22:20 ` H.J. Lu 2022-01-11 22:52 ` Florian Weimer 0 siblings, 1 reply; 14+ messages in thread From: H.J. Lu @ 2022-01-11 22:20 UTC (permalink / raw) To: Florian Weimer; +Cc: GNU C Library, Jakub Jelinek On Tue, Jan 11, 2022 at 12:37 PM Florian Weimer <fweimer@redhat.com> wrote: > > * H. J. Lu: > > > On Tue, Jan 11, 2022 at 6:00 AM H.J. Lu <hjl.tools@gmail.com> wrote: > >> > >> On Tue, Jan 11, 2022 at 2:05 AM Florian Weimer <fweimer@redhat.com> wrote: > >> > > >> > The configure check for CAN_USE_REGISTER_ASM_EBP is unreliable. And we > >> > used it to switch away from using %ebx in assembler constraints, but > >> > this appears to be no longer necessary. > >> > >> This GCC bug has been fixed in GCC 5 as seen in > >> > >> commit 021478683cc091de9902d297a7b161f8343ffb6a > >> Author: Uros Bizjak <uros@gcc.gnu.org> > >> Date: Fri Oct 17 08:00:58 2014 +0200 > >> > >> cpuid.h (__cpuid): Remove definitions that handle %ebx register in > >> a special way. > >> > >> * config/i386/cpuid.h (__cpuid): Remove definitions that handle %ebx > >> register in a special way. > >> (__cpuid_count): Ditto. > >> * config/i386/driver-i386.h: Protect with > >> "#if defined(__GNUC__) && (__GNUC__ >= 5 || !defined(__PIC__))". > >> (host_detect_local_cpu): Mention that GCC with non-fixed %ebx > >> is required to compile the function. > >> > >> From-SVN: r216362 > >> > >> Since GCC 6.2 or above is required to build glibc, please > >> remove the !OPTIMIZE_FOR_GCC_5 path and this issue > >> will be resolved automatically. > > > > There are > > > > /* Since GCC 5 and above can properly spill %ebx with PIC when needed, > > we can inline syscalls with 6 arguments if GCC 5 or above is used > > to compile glibc. Disable GCC 5 optimization when compiling for > > profiling or when -fno-omit-frame-pointer is used since asm ("ebp") > > can't be used to put the 6th argument in %ebp for syscall. */ > > #if !defined PROF && CAN_USE_REGISTER_ASM_EBP > > # define OPTIMIZE_FOR_GCC_5 > > #endif > > > > If we want to support profiling or -fno-omit-frame-pointer, > > we need to keep these codes. > > This is strictly for %ebp, I think, as indicated by the comment. %ebx > does not need to be special-cased for profiling. > > I assume that building glibc (with profiling) is proof enough that this > works? You need to test glibc build with -fno-omit-frame-pointer. -- H.J. ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 0/2] Remove some i386 system call optimizations 2022-01-11 22:20 ` H.J. Lu @ 2022-01-11 22:52 ` Florian Weimer 2022-01-12 18:49 ` H.J. Lu 0 siblings, 1 reply; 14+ messages in thread From: Florian Weimer @ 2022-01-11 22:52 UTC (permalink / raw) To: H.J. Lu; +Cc: GNU C Library, Jakub Jelinek * H. J. Lu: >> > There are >> > >> > /* Since GCC 5 and above can properly spill %ebx with PIC when needed, >> > we can inline syscalls with 6 arguments if GCC 5 or above is used >> > to compile glibc. Disable GCC 5 optimization when compiling for >> > profiling or when -fno-omit-frame-pointer is used since asm ("ebp") >> > can't be used to put the 6th argument in %ebp for syscall. */ >> > #if !defined PROF && CAN_USE_REGISTER_ASM_EBP >> > # define OPTIMIZE_FOR_GCC_5 >> > #endif >> > >> > If we want to support profiling or -fno-omit-frame-pointer, >> > we need to keep these codes. >> >> This is strictly for %ebp, I think, as indicated by the comment. %ebx >> does not need to be special-cased for profiling. >> >> I assume that building glibc (with profiling) is proof enough that this >> works? > > You need to test glibc build with -fno-omit-frame-pointer. I tried it, it works (with both patches applied). -fno-omit-frame-pointer is about %ebp, not %ebx. Thanks, Florian ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 0/2] Remove some i386 system call optimizations 2022-01-11 22:52 ` Florian Weimer @ 2022-01-12 18:49 ` H.J. Lu 2022-01-12 19:37 ` Florian Weimer 0 siblings, 1 reply; 14+ messages in thread From: H.J. Lu @ 2022-01-12 18:49 UTC (permalink / raw) To: Florian Weimer; +Cc: GNU C Library, Jakub Jelinek On Tue, Jan 11, 2022 at 2:52 PM Florian Weimer <fweimer@redhat.com> wrote: > > * H. J. Lu: > > >> > There are > >> > > >> > /* Since GCC 5 and above can properly spill %ebx with PIC when needed, > >> > we can inline syscalls with 6 arguments if GCC 5 or above is used > >> > to compile glibc. Disable GCC 5 optimization when compiling for > >> > profiling or when -fno-omit-frame-pointer is used since asm ("ebp") > >> > can't be used to put the 6th argument in %ebp for syscall. */ > >> > #if !defined PROF && CAN_USE_REGISTER_ASM_EBP > >> > # define OPTIMIZE_FOR_GCC_5 > >> > #endif > >> > > >> > If we want to support profiling or -fno-omit-frame-pointer, > >> > we need to keep these codes. > >> > >> This is strictly for %ebp, I think, as indicated by the comment. %ebx > >> does not need to be special-cased for profiling. > >> > >> I assume that building glibc (with profiling) is proof enough that this > >> works? > > > > You need to test glibc build with -fno-omit-frame-pointer. > > I tried it, it works (with both patches applied). > -fno-omit-frame-pointer is about %ebp, not %ebx. > > Thanks, > Florian > Do they have to be in glibc 2.35? If not, I prefer to do it after 2.35 is branched. Thanks. -- H.J. ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 0/2] Remove some i386 system call optimizations 2022-01-12 18:49 ` H.J. Lu @ 2022-01-12 19:37 ` Florian Weimer 2022-01-12 19:56 ` H.J. Lu 0 siblings, 1 reply; 14+ messages in thread From: Florian Weimer @ 2022-01-12 19:37 UTC (permalink / raw) To: H.J. Lu; +Cc: GNU C Library, Jakub Jelinek * H. J. Lu: > On Tue, Jan 11, 2022 at 2:52 PM Florian Weimer <fweimer@redhat.com> wrote: >> >> * H. J. Lu: >> >> >> > There are >> >> > >> >> > /* Since GCC 5 and above can properly spill %ebx with PIC when needed, >> >> > we can inline syscalls with 6 arguments if GCC 5 or above is used >> >> > to compile glibc. Disable GCC 5 optimization when compiling for >> >> > profiling or when -fno-omit-frame-pointer is used since asm ("ebp") >> >> > can't be used to put the 6th argument in %ebp for syscall. */ >> >> > #if !defined PROF && CAN_USE_REGISTER_ASM_EBP >> >> > # define OPTIMIZE_FOR_GCC_5 >> >> > #endif >> >> > >> >> > If we want to support profiling or -fno-omit-frame-pointer, >> >> > we need to keep these codes. >> >> >> >> This is strictly for %ebp, I think, as indicated by the comment. %ebx >> >> does not need to be special-cased for profiling. >> >> >> >> I assume that building glibc (with profiling) is proof enough that this >> >> works? >> > >> > You need to test glibc build with -fno-omit-frame-pointer. >> >> I tried it, it works (with both patches applied). >> -fno-omit-frame-pointer is about %ebp, not %ebx. >> >> Thanks, >> Florian >> > > Do they have to be in glibc 2.35? If not, I prefer to do it after > 2.35 is branched. We can't build glibc 2.35 with GCC 12 in Fedora without these changes. The %ebp avoidance I can activate with a configure argument, but the macros for optimized %ebx usage are incompatible with .altmacro, as used by the current Systemtap probes. Thanks, Florian ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 0/2] Remove some i386 system call optimizations 2022-01-12 19:37 ` Florian Weimer @ 2022-01-12 19:56 ` H.J. Lu 2022-01-12 20:12 ` Florian Weimer 0 siblings, 1 reply; 14+ messages in thread From: H.J. Lu @ 2022-01-12 19:56 UTC (permalink / raw) To: Florian Weimer; +Cc: GNU C Library, Jakub Jelinek On Wed, Jan 12, 2022 at 11:37 AM Florian Weimer <fweimer@redhat.com> wrote: > > * H. J. Lu: > > > On Tue, Jan 11, 2022 at 2:52 PM Florian Weimer <fweimer@redhat.com> wrote: > >> > >> * H. J. Lu: > >> > >> >> > There are > >> >> > > >> >> > /* Since GCC 5 and above can properly spill %ebx with PIC when needed, > >> >> > we can inline syscalls with 6 arguments if GCC 5 or above is used > >> >> > to compile glibc. Disable GCC 5 optimization when compiling for > >> >> > profiling or when -fno-omit-frame-pointer is used since asm ("ebp") > >> >> > can't be used to put the 6th argument in %ebp for syscall. */ > >> >> > #if !defined PROF && CAN_USE_REGISTER_ASM_EBP > >> >> > # define OPTIMIZE_FOR_GCC_5 > >> >> > #endif > >> >> > > >> >> > If we want to support profiling or -fno-omit-frame-pointer, > >> >> > we need to keep these codes. > >> >> > >> >> This is strictly for %ebp, I think, as indicated by the comment. %ebx > >> >> does not need to be special-cased for profiling. > >> >> > >> >> I assume that building glibc (with profiling) is proof enough that this > >> >> works? > >> > > >> > You need to test glibc build with -fno-omit-frame-pointer. > >> > >> I tried it, it works (with both patches applied). > >> -fno-omit-frame-pointer is about %ebp, not %ebx. > >> > >> Thanks, > >> Florian > >> > > > > Do they have to be in glibc 2.35? If not, I prefer to do it after > > 2.35 is branched. > > We can't build glibc 2.35 with GCC 12 in Fedora without these changes. > > The %ebp avoidance I can activate with a configure argument, but the > macros for optimized %ebx usage are incompatible with .altmacro, as used > by the current Systemtap probes. Please open a glibc bug with a reproducer and CC me. Thanks. -- H.J. ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 0/2] Remove some i386 system call optimizations 2022-01-12 19:56 ` H.J. Lu @ 2022-01-12 20:12 ` Florian Weimer 2022-01-12 21:59 ` H.J. Lu 0 siblings, 1 reply; 14+ messages in thread From: Florian Weimer @ 2022-01-12 20:12 UTC (permalink / raw) To: H.J. Lu; +Cc: GNU C Library, Jakub Jelinek * H. J. Lu: > On Wed, Jan 12, 2022 at 11:37 AM Florian Weimer <fweimer@redhat.com> wrote: >> >> * H. J. Lu: >> >> > On Tue, Jan 11, 2022 at 2:52 PM Florian Weimer <fweimer@redhat.com> wrote: >> >> >> >> * H. J. Lu: >> >> >> >> >> > There are >> >> >> > >> >> >> > /* Since GCC 5 and above can properly spill %ebx with PIC when needed, >> >> >> > we can inline syscalls with 6 arguments if GCC 5 or above is used >> >> >> > to compile glibc. Disable GCC 5 optimization when compiling for >> >> >> > profiling or when -fno-omit-frame-pointer is used since asm ("ebp") >> >> >> > can't be used to put the 6th argument in %ebp for syscall. */ >> >> >> > #if !defined PROF && CAN_USE_REGISTER_ASM_EBP >> >> >> > # define OPTIMIZE_FOR_GCC_5 >> >> >> > #endif >> >> >> > >> >> >> > If we want to support profiling or -fno-omit-frame-pointer, >> >> >> > we need to keep these codes. >> >> >> >> >> >> This is strictly for %ebp, I think, as indicated by the comment. %ebx >> >> >> does not need to be special-cased for profiling. >> >> >> >> >> >> I assume that building glibc (with profiling) is proof enough that this >> >> >> works? >> >> > >> >> > You need to test glibc build with -fno-omit-frame-pointer. >> >> >> >> I tried it, it works (with both patches applied). >> >> -fno-omit-frame-pointer is about %ebp, not %ebx. >> >> >> >> Thanks, >> >> Florian >> >> >> > >> > Do they have to be in glibc 2.35? If not, I prefer to do it after >> > 2.35 is branched. >> >> We can't build glibc 2.35 with GCC 12 in Fedora without these changes. >> >> The %ebp avoidance I can activate with a configure argument, but the >> macros for optimized %ebx usage are incompatible with .altmacro, as used >> by the current Systemtap probes. > > Please open a glibc bug with a reproducer and CC me. Done: <https://sourceware.org/bugzilla/show_bug.cgi?id=28771> Thanks, Florian ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 0/2] Remove some i386 system call optimizations 2022-01-12 20:12 ` Florian Weimer @ 2022-01-12 21:59 ` H.J. Lu 2022-01-12 22:33 ` Florian Weimer 0 siblings, 1 reply; 14+ messages in thread From: H.J. Lu @ 2022-01-12 21:59 UTC (permalink / raw) To: Florian Weimer; +Cc: GNU C Library, Jakub Jelinek On Wed, Jan 12, 2022 at 12:12 PM Florian Weimer <fweimer@redhat.com> wrote: > > * H. J. Lu: > > > On Wed, Jan 12, 2022 at 11:37 AM Florian Weimer <fweimer@redhat.com> wrote: > >> > >> * H. J. Lu: > >> > >> > On Tue, Jan 11, 2022 at 2:52 PM Florian Weimer <fweimer@redhat.com> wrote: > >> >> > >> >> * H. J. Lu: > >> >> > >> >> >> > There are > >> >> >> > > >> >> >> > /* Since GCC 5 and above can properly spill %ebx with PIC when needed, > >> >> >> > we can inline syscalls with 6 arguments if GCC 5 or above is used > >> >> >> > to compile glibc. Disable GCC 5 optimization when compiling for > >> >> >> > profiling or when -fno-omit-frame-pointer is used since asm ("ebp") > >> >> >> > can't be used to put the 6th argument in %ebp for syscall. */ > >> >> >> > #if !defined PROF && CAN_USE_REGISTER_ASM_EBP > >> >> >> > # define OPTIMIZE_FOR_GCC_5 > >> >> >> > #endif > >> >> >> > > >> >> >> > If we want to support profiling or -fno-omit-frame-pointer, > >> >> >> > we need to keep these codes. > >> >> >> > >> >> >> This is strictly for %ebp, I think, as indicated by the comment. %ebx > >> >> >> does not need to be special-cased for profiling. > >> >> >> > >> >> >> I assume that building glibc (with profiling) is proof enough that this > >> >> >> works? > >> >> > > >> >> > You need to test glibc build with -fno-omit-frame-pointer. > >> >> > >> >> I tried it, it works (with both patches applied). > >> >> -fno-omit-frame-pointer is about %ebp, not %ebx. > >> >> > >> >> Thanks, > >> >> Florian > >> >> > >> > > >> > Do they have to be in glibc 2.35? If not, I prefer to do it after > >> > 2.35 is branched. > >> > >> We can't build glibc 2.35 with GCC 12 in Fedora without these changes. > >> > >> The %ebp avoidance I can activate with a configure argument, but the > >> macros for optimized %ebx usage are incompatible with .altmacro, as used > >> by the current Systemtap probes. > > > > Please open a glibc bug with a reproducer and CC me. > > Done: <https://sourceware.org/bugzilla/show_bug.cgi?id=28771> > OPTIMIZE_FOR_GCC_5 enables 2 things: one is let GCC handle -fPIC and the other is use register int reg asm ("ebp") which is unreliable. You want to let GCC handle -fPIC and remove CAN_USE_REGISTER_ASM_EBP. If this is correct, please combine 2 patches into one and reference BZ #28771 in the commit log. Thanks. -- H.J. ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH 0/2] Remove some i386 system call optimizations 2022-01-12 21:59 ` H.J. Lu @ 2022-01-12 22:33 ` Florian Weimer 0 siblings, 0 replies; 14+ messages in thread From: Florian Weimer @ 2022-01-12 22:33 UTC (permalink / raw) To: H.J. Lu; +Cc: GNU C Library, Jakub Jelinek * H. J. Lu: > OPTIMIZE_FOR_GCC_5 enables 2 things: one is let GCC handle > -fPIC and the other is use > > register int reg asm ("ebp") > > which is unreliable. You want to let GCC handle -fPIC and > remove CAN_USE_REGISTER_ASM_EBP. If this is correct, > please combine 2 patches into one and reference BZ #28771 > in the commit log. Yes, that is an accurate summary. I will send a patch according to your suggestions tomorrow. Thanks, Florian ^ permalink raw reply [flat|nested] 14+ messages in thread
end of thread, other threads:[~2022-01-12 22:38 UTC | newest] Thread overview: 14+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2022-01-11 10:05 [PATCH 0/2] Remove some i386 system call optimizations Florian Weimer 2022-01-11 10:06 ` [PATCH 1/2] i386: Always treat %ebx as an allocatable register Florian Weimer 2022-01-11 10:06 ` [PATCH 2/2] i386: Always use __libc_do_syscall for 6-argument syscalls (bug 27997) Florian Weimer 2022-01-11 14:00 ` [PATCH 0/2] Remove some i386 system call optimizations H.J. Lu 2022-01-11 20:30 ` H.J. Lu 2022-01-11 20:37 ` Florian Weimer 2022-01-11 22:20 ` H.J. Lu 2022-01-11 22:52 ` Florian Weimer 2022-01-12 18:49 ` H.J. Lu 2022-01-12 19:37 ` Florian Weimer 2022-01-12 19:56 ` H.J. Lu 2022-01-12 20:12 ` Florian Weimer 2022-01-12 21:59 ` H.J. Lu 2022-01-12 22:33 ` Florian Weimer
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