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| author | Alejandro Colomar <alx.manpages@gmail.com> | 2022-09-05 23:03:38 +0200 |
|---|---|---|
| committer | Alejandro Colomar <alx.manpages@gmail.com> | 2022-09-05 23:03:47 +0200 |
| commit | 70ac1c4785fc1e158ab2349a962dba2526bf4fbc (patch) | |
| tree | bff270e2496dd284bccfc1271b43946f5d225224 /man/man2/cacheflush.2 | |
| parent | 5423a6f86b2b920a5f3e8cf8d759b513050f2d33 (diff) | |
| download | man-pages-70ac1c4785fc1e158ab2349a962dba2526bf4fbc.tar.gz | |
src.mk, All pages: Move man* to man/
The root of the repository is becoming a bit overpopulated and
unorganized, due to the recent addition of more mandirs, and more
informative and configuration files too. Let's create a specific
mandir <man/> that contains the mandirs <man[1-8]*>.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Diffstat (limited to 'man/man2/cacheflush.2')
| -rw-r--r-- | man/man2/cacheflush.2 | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/man/man2/cacheflush.2 b/man/man2/cacheflush.2 new file mode 100644 index 0000000000..1f081caa44 --- /dev/null +++ b/man/man2/cacheflush.2 @@ -0,0 +1,144 @@ +.\" Written by Ralf Baechle (ralf@waldorf-gmbh.de), +.\" Copyright (c) 1994, 1995 Waldorf GMBH +.\" +.\" SPDX-License-Identifier: GPL-2.0-or-later +.\" +.TH CACHEFLUSH 2 2021-03-22 "Linux man-pages (unreleased)" +.SH NAME +cacheflush \- flush contents of instruction and/or data cache +.SH LIBRARY +Standard C library +.RI ( libc ", " \-lc ) +.SH SYNOPSIS +.nf +.B #include <sys/cachectl.h> +.PP +.BI "int cacheflush(void *" addr ", int "nbytes ", int "cache ); +.fi +.PP +.IR Note : +On some architectures, +there is no glibc wrapper for this system call; see NOTES. +.SH DESCRIPTION +.BR cacheflush () +flushes the contents of the indicated cache(s) for the +user addresses in the range +.I addr +to +.IR (addr+nbytes\-1) . +.I cache +may be one of: +.TP +.B ICACHE +Flush the instruction cache. +.TP +.B DCACHE +Write back to memory and invalidate the affected valid cache lines. +.TP +.B BCACHE +Same as +.BR (ICACHE|DCACHE) . +.SH RETURN VALUE +.BR cacheflush () +returns 0 on success. +On error, it returns \-1 and sets +.I errno +to indicate the error. +.SH ERRORS +.TP +.B EFAULT +Some or all of the address range +.I addr +to +.I (addr+nbytes\-1) +is not accessible. +.TP +.B EINVAL +.I cache +is not one of +.BR ICACHE , +.BR DCACHE , +or +.B BCACHE +(but see BUGS). +.SH STANDARDS +Historically, this system call was available on all MIPS UNIX variants +including RISC/os, IRIX, Ultrix, NetBSD, OpenBSD, and FreeBSD +(and also on some non-UNIX MIPS operating systems), so that +the existence of this call in MIPS operating systems is a de-facto +standard. +.SS Caveat +.BR cacheflush () +should not be used in programs intended to be portable. +On Linux, this call first appeared on the MIPS architecture, +but nowadays, Linux provides a +.BR cacheflush () +system call on some other architectures, but with different arguments. +.SH NOTES +.SS Architecture-specific variants +Glibc provides a wrapper for this system call, +with the prototype shown in SYNOPSIS, +for the following architectures: +ARC, CSKY, MIPS, and NIOS2. +.PP +On some other architectures, +Linux provides this system call, with different arguments: +.TP +M68K: +.nf +.BI "int cacheflush(unsigned long " addr ", int " scope ", int " cache , +.BI " unsigned long " len ); +.fi +.TP +SH: +.nf +.BI "int cacheflush(unsigned long " addr ", unsigned long " len ", int " op ); +.fi +.TP +NDS32: +.nf +.BI "int cacheflush(unsigned int " start ", unsigned int " end ", int " cache ); +.fi +.PP +On the above architectures, +glibc does not provide a wrapper for this system call; call it using +.BR syscall (2). +.SS GCC alternative +Unless you need the finer grained control that this system call provides, +you probably want to use the GCC built-in function +.BR __builtin___clear_cache (), +which provides a portable interface +across platforms supported by GCC and compatible compilers: +.PP +.in +4n +.EX +.BI "void __builtin___clear_cache(void *" begin ", void *" end ); +.EE +.in +.PP +On platforms that don't require instruction cache flushes, +.BR __builtin___clear_cache () +has no effect. +.PP +.IR Note : +On some GCC-compatible compilers, +the prototype for this built-in function uses +.I char * +instead of +.I void * +for the parameters. +.SH BUGS +Linux kernels older than version 2.6.11 ignore the +.I addr +and +.I nbytes +arguments, making this function fairly expensive. +Therefore, the whole cache is always flushed. +.PP +This function always behaves as if +.B BCACHE +has been passed for the +.I cache +argument and does not do any error checking on the +.I cache +argument. |