syscalls: Remove start and number from syscall_get_arguments() args
authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>
Mon, 7 Nov 2016 21:26:37 +0000 (16:26 -0500)
committerSteven Rostedt (VMware) <rostedt@goodmis.org>
Fri, 5 Apr 2019 13:26:43 +0000 (09:26 -0400)
commitb35f549df1d7520d37ba1e6d4a8d4df6bd52d136
treeb7e544da953806a2f4d9b2d0aeb167d0baad3955
parented3bb007021b9bddb90afae28a19f08ed8890add
syscalls: Remove start and number from syscall_get_arguments() args

At Linux Plumbers, Andy Lutomirski approached me and pointed out that the
function call syscall_get_arguments() implemented in x86 was horribly
written and not optimized for the standard case of passing in 0 and 6 for
the starting index and the number of system calls to get. When looking at
all the users of this function, I discovered that all instances pass in only
0 and 6 for these arguments. Instead of having this function handle
different cases that are never used, simply rewrite it to return the first 6
arguments of a system call.

This should help out the performance of tracing system calls by ptrace,
ftrace and perf.

Link: http://lkml.kernel.org/r/20161107213233.754809394@goodmis.org
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Dave Martin <dave.martin@arm.com>
Cc: "Dmitry V. Levin" <ldv@altlinux.org>
Cc: x86@kernel.org
Cc: linux-snps-arc@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-c6x-dev@linux-c6x.org
Cc: uclinux-h8-devel@lists.sourceforge.jp
Cc: linux-hexagon@vger.kernel.org
Cc: linux-ia64@vger.kernel.org
Cc: linux-mips@vger.kernel.org
Cc: nios2-dev@lists.rocketboards.org
Cc: openrisc@lists.librecores.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-riscv@lists.infradead.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: sparclinux@vger.kernel.org
Cc: linux-um@lists.infradead.org
Cc: linux-xtensa@linux-xtensa.org
Cc: linux-arch@vger.kernel.org
Acked-by: Paul Burton <paul.burton@mips.com> # MIPS parts
Acked-by: Max Filippov <jcmvbkbc@gmail.com> # For xtensa changes
Acked-by: Will Deacon <will.deacon@arm.com> # For the arm64 bits
Reviewed-by: Thomas Gleixner <tglx@linutronix.de> # for x86
Reviewed-by: Dmitry V. Levin <ldv@altlinux.org>
Reported-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
29 files changed:
arch/arc/include/asm/syscall.h
arch/arm/include/asm/syscall.h
arch/arm64/include/asm/syscall.h
arch/c6x/include/asm/syscall.h
arch/csky/include/asm/syscall.h
arch/h8300/include/asm/syscall.h
arch/hexagon/include/asm/syscall.h
arch/ia64/include/asm/syscall.h
arch/microblaze/include/asm/syscall.h
arch/mips/include/asm/syscall.h
arch/mips/kernel/ptrace.c
arch/nds32/include/asm/syscall.h
arch/nios2/include/asm/syscall.h
arch/openrisc/include/asm/syscall.h
arch/parisc/include/asm/syscall.h
arch/powerpc/include/asm/syscall.h
arch/riscv/include/asm/syscall.h
arch/s390/include/asm/syscall.h
arch/sh/include/asm/syscall_32.h
arch/sh/include/asm/syscall_64.h
arch/sparc/include/asm/syscall.h
arch/um/include/asm/syscall-generic.h
arch/x86/include/asm/syscall.h
arch/xtensa/include/asm/syscall.h
include/asm-generic/syscall.h
include/trace/events/syscalls.h
kernel/seccomp.c
kernel/trace/trace_syscalls.c
lib/syscall.c