Hi Michael, Continuing with the changes in this thread: https://lore.kernel.org/linux-man/747d56e0-c102-ab40-add4-530a48a43a4d@xxxxxx/T/#t I researched the architectures that have this syscall. I found some that clearly provide the syscall, and some that seem to have something, but I didn't find a definition in the kernel (i.e., ARM, MicroBlaze (glibc only)?) Research: $ grep -rn cacheflush glibc/ glibc/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist:324:GLIBC_2.0 cacheflush F glibc/sysdeps/unix/sysv/linux/m68k/Versions:13: cacheflush; glibc/sysdeps/unix/sysv/linux/m68k/arch-syscall.h:17:#define __NR_cacheflush 123 glibc/sysdeps/unix/sysv/linux/m68k/syscalls.list:18:cacheflush EXTRA cacheflush i:iiii __cacheflush cacheflush glibc/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist:744:GLIBC_2.4 cacheflush F glibc/sysdeps/unix/sysv/linux/arc/Versions:10: cacheflush; glibc/sysdeps/unix/sysv/linux/arc/sys/cachectl.h:1:/* cacheflush - flush contents of instruction and/or data cache. glibc/sysdeps/unix/sysv/linux/arc/sys/cachectl.h:30:extern int cacheflush (void *__addr, int __nbytes, int __op) __THROW; glibc/sysdeps/unix/sysv/linux/arc/arch-syscall.h:13:#define __NR_cacheflush 244 glibc/sysdeps/unix/sysv/linux/arc/syscalls.list:3:cacheflush - cacheflush i:pii _flush_cache cacheflush glibc/sysdeps/unix/sysv/linux/arc/Makefile:10:# MIPS/Tile-style cacheflush routine glibc/sysdeps/unix/sysv/linux/arc/Makefile:12:sysdep_routines += cacheflush glibc/sysdeps/unix/sysv/linux/arc/libc.abilist:574:GLIBC_2.32 cacheflush F glibc/sysdeps/unix/sysv/linux/csky/Versions:3: cacheflush; glibc/sysdeps/unix/sysv/linux/csky/sys/cachectl.h:30:extern int cacheflush (void *__addr, const int __nbytes, glibc/sysdeps/unix/sysv/linux/csky/arch-syscall.h:10:#define __NR_cacheflush 245 glibc/sysdeps/unix/sysv/linux/csky/syscalls.list:2:cacheflush - cacheflush i:pii _flush_cache cacheflush glibc/sysdeps/unix/sysv/linux/csky/Makefile:2:sysdep_routines += cacheflush glibc/sysdeps/unix/sysv/linux/csky/libc.abilist:594:GLIBC_2.29 cacheflush F glibc/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist:322:GLIBC_2.0 cacheflush F glibc/sysdeps/unix/sysv/linux/mips/mips32/arch-syscall.h:19:#define __NR_cacheflush 4147 glibc/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist:322:GLIBC_2.0 cacheflush F glibc/sysdeps/unix/sysv/linux/mips/Versions:19: cachectl; cacheflush; glibc/sysdeps/unix/sysv/linux/mips/sys/cachectl.h:35:extern int cacheflush (void *__addr, const int __nbytes, const int __op) __THROW; glibc/sysdeps/unix/sysv/linux/mips/mips64/n64/arch-syscall.h:16:#define __NR_cacheflush 5197 glibc/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist:320:GLIBC_2.0 cacheflush F glibc/sysdeps/unix/sysv/linux/mips/mips64/n32/arch-syscall.h:16:#define __NR_cacheflush 6197 glibc/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist:322:GLIBC_2.0 cacheflush F glibc/sysdeps/unix/sysv/linux/mips/syscalls.list:8:cacheflush - cacheflush i:pii _flush_cache cacheflush glibc/sysdeps/unix/sysv/linux/mips/Makefile:6:sysdep_routines += cachectl cacheflush sysmips _test_and_set glibc/sysdeps/unix/sysv/linux/sh/arch-syscall.h:16:#define __NR_cacheflush 123 glibc/sysdeps/unix/sysv/linux/nios2/Versions:4: cacheflush; glibc/sysdeps/unix/sysv/linux/nios2/sys/cachectl.h:1:/* cacheflush - flush contents of instruction and/or data cache. glibc/sysdeps/unix/sysv/linux/nios2/sys/cachectl.h:27:extern int cacheflush (void *__addr, const int __nbytes, const int __op) __THROW; glibc/sysdeps/unix/sysv/linux/nios2/arch-syscall.h:10:#define __NR_cacheflush 244 glibc/sysdeps/unix/sysv/linux/nios2/cacheflush.c:1:/* cacheflush system call for Nios II Linux. glibc/sysdeps/unix/sysv/linux/nios2/cacheflush.c:27: return INLINE_SYSCALL (cacheflush, 3, addr, nbytes, op); glibc/sysdeps/unix/sysv/linux/nios2/cacheflush.c:29:weak_alias (_flush_cache, cacheflush) glibc/sysdeps/unix/sysv/linux/nios2/Makefile:6:# MIPS-style cacheflush routine glibc/sysdeps/unix/sysv/linux/nios2/Makefile:8:sysdep_routines += cacheflush glibc/sysdeps/unix/sysv/linux/nios2/libc.abilist:663:GLIBC_2.21 cacheflush F glibc/sysdeps/unix/sysv/linux/arm/dl-machine.h:23: INTERNAL_SYSCALL_CALL (cacheflush, (BEG), (END), 0) glibc/sysdeps/unix/sysv/linux/arm/arch-syscall.h:17:#define __NR_cacheflush 983042 glibc/sysdeps/unix/sysv/linux/arm/fixup-asm-unistd.h:19:#ifndef __NR_cacheflush glibc/sysdeps/unix/sysv/linux/arm/fixup-asm-unistd.h:20:# define __NR_cacheflush __ARM_NR_cacheflush glibc/sysdeps/unix/sysv/linux/microblaze/syscalls.list:3:cacheflush EXTRA cacheflush i:iiii __cacheflush cacheflush glibc/sysdeps/unix/sysv/linux/syscall-names.list:60:cacheflush glibc/benchtests/strcoll-inputs/filelist#en_US.UTF-8:1417:cacheflush.c glibc/benchtests/strcoll-inputs/filelist#en_US.UTF-8:1744:cacheflush.c glibc/ChangeLog.old/ChangeLog.7:7489: * sysdeps/mach/mips/cacheflush.c: Likewise. glibc/ChangeLog.old/ChangeLog.7:9422: * sysdeps/unix/sysv/linux/m68k/syscalls.list: Add cacheflush. glibc/ChangeLog.old/ChangeLog.4:205: * sysdeps/mach/mips/cacheflush.c: New file. glibc/ChangeLog.old/ChangeLog.18:40858: * sysdeps/unix/sysv/linux/nios2/cacheflush.c: New file. glibc/ChangeLog.old/ChangeLog.ports-tile:700: * sysdeps/unix/sysv/linux/tile/cacheflush.c: New file. grep: glibc/.git/index: binary file matches $ grep -rn -e 'sys_cacheflush' -e 'SYSCALL_DEFINE.(cacheflush,' linux/ | grep -v -e '/arc/' -e '/csky/' -e '/mips/' -e '/nios2/' tools/testing/selftests/futex/functional/usr/include/linux/capability.h:251:/* Allow flushing all cache on m68k (sys_cacheflush) */ include/uapi/linux/capability.h:253:/* Allow flushing all cache on m68k (sys_cacheflush) */ arch/m68k/kernel/sys_m68k.c:376:/* sys_cacheflush -- flush (part of) the processor cache. */ arch/m68k/kernel/sys_m68k.c:378:sys_cacheflush (unsigned long addr, int scope, int cache, unsigned long len) arch/m68k/kernel/sys_m68k.c:531:/* sys_cacheflush -- flush (part of) the processor cache. */ arch/m68k/kernel/sys_m68k.c:533:sys_cacheflush (unsigned long addr, int scope, int cache, unsigned long len) arch/m68k/kernel/syscalls/syscall.tbl:133:123 common cacheflush sys_cacheflush arch/sh/kernel/sys_sh.c:57:/* sys_cacheflush -- flush (part of) the processor cache. */ arch/sh/kernel/sys_sh.c:58:asmlinkage int sys_cacheflush(unsigned long addr, unsigned long len, int op) arch/sh/kernel/syscalls/syscall.tbl:133:123 common cacheflush sys_cacheflush arch/arm/include/asm/cacheflush.h:263: * This is used for the ARM private sys_cacheflush system call. arch/nds32/include/uapi/asm/unistd.h:15:__SYSCALL(__NR_cacheflush, sys_cacheflush) arch/nds32/include/asm/syscalls.h:7:asmlinkage long sys_cacheflush(unsigned long addr, unsigned long len, unsigned int op); arch/nds32/kernel/sys_nds32.c:29:SYSCALL_DEFINE3(cacheflush, unsigned int, start, unsigned int, end, int, cache) Rendered page (NOTES only): [ NOTES Architecture-specific variants Glibc provides a wrapper for this system call, with the pro‐ totype shown in SYNOPSIS, for the following architectures: ARC, CSKY, MIPS, and NIOS2. // lowercase? On some other architectures, Linux provides this system call with different arguments: M68K: int cacheflush(unsigned long addr, int scope, int cache, unsigned long len); SH: int cacheflush(unsigned long addr, unsigned long len, int op); NDS32: int cacheflush(unsigned int start, unsigned int end, int cache); // ARM?? GCC alternative Unless you need the finer grained control that this system call provides, you probably want to use the GCC built-in function __builtin___clear_cache(), which provides a portable interface across platforms supported by GCC and compatible compilers: void __builtin___clear_cache(void *begin, void *end); On platforms that don't require instruction cache flushes, __builtin___clear_cache() has no effect. Note: On some GCC-compatible compilers, such as clang, the prototype for this function uses char * instead of void * for the parameters. ] 'GCC alternative' is the name I gave to the NOTES from the other thread, which aren't yet merged (I'll send the patches after the weekend, probably). Subsections based on: fadvise64(2) Can you review this? Thanks, Alex -- Alejandro Colomar Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/ http://www.alejandro-colomar.es
