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authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>2016-11-07 16:26:37 -0500
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2019-04-05 09:26:43 -0400
commitb35f549df1d7520d37ba1e6d4a8d4df6bd52d136 (patch)
treeb7e544da953806a2f4d9b2d0aeb167d0baad3955 /lib
parented3bb007021b9bddb90afae28a19f08ed8890add (diff)
downloadlinux-stericsson-b35f549df1d7520d37ba1e6d4a8d4df6bd52d136.tar.gz
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>
Diffstat (limited to 'lib')
-rw-r--r--lib/syscall.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/syscall.c b/lib/syscall.c
index e8467e17b9a2..fb328e7ccb08 100644
--- a/lib/syscall.c
+++ b/lib/syscall.c
@@ -27,7 +27,7 @@ static int collect_syscall(struct task_struct *target, struct syscall_info *info
info->data.nr = syscall_get_nr(target, regs);
if (info->data.nr != -1L)
- syscall_get_arguments(target, regs, 0, 6,
+ syscall_get_arguments(target, regs,
(unsigned long *)&info->data.args[0]);
put_task_stack(target);