From 1b7b9c650ebb94358365512199559b0ece3e657c Mon Sep 17 00:00:00 2001 From: Michael Jeanson Date: Tue, 9 Apr 2019 14:12:41 -0400 Subject: [PATCH] Fix: Remove start and number from syscall_get_arguments() args (v5.1) commit b35f549df1d7520d37ba1e6d4a8d4df6bd52d136 Author: Steven Rostedt (Red Hat) Date: Mon Nov 7 16:26:37 2016 -0500 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 Signed-off-by: Michael Jeanson Signed-off-by: Mathieu Desnoyers --- lttng-syscalls.c | 57 ++++++++++++++++++++++++----------------------- wrapper/syscall.h | 34 ++++++++++++++++++++++++++++ 2 files changed, 63 insertions(+), 28 deletions(-) create mode 100644 wrapper/syscall.h diff --git a/lttng-syscalls.c b/lttng-syscalls.c index bcc06b5c..ebd9246c 100644 --- a/lttng-syscalls.c +++ b/lttng-syscalls.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #ifndef CONFIG_COMPAT @@ -361,9 +362,9 @@ struct lttng_syscall_filter { static void syscall_entry_unknown(struct lttng_event *event, struct pt_regs *regs, unsigned int id) { - unsigned long args[UNKNOWN_SYSCALL_NRARGS]; + unsigned long args[LTTNG_SYSCALL_NR_ARGS]; - syscall_get_arguments(current, regs, 0, UNKNOWN_SYSCALL_NRARGS, args); + lttng_syscall_get_arguments(current, regs, args); if (unlikely(in_compat_syscall())) __event_probe__compat_syscall_entry_unknown(event, id, args); else @@ -432,9 +433,9 @@ void syscall_entry_probe(void *__data, struct pt_regs *regs, long id) case 1: { void (*fptr)(void *__data, unsigned long arg0) = entry->func; - unsigned long args[1]; + unsigned long args[LTTNG_SYSCALL_NR_ARGS]; - syscall_get_arguments(current, regs, 0, entry->nrargs, args); + lttng_syscall_get_arguments(current, regs, args); fptr(event, args[0]); break; } @@ -443,9 +444,9 @@ void syscall_entry_probe(void *__data, struct pt_regs *regs, long id) void (*fptr)(void *__data, unsigned long arg0, unsigned long arg1) = entry->func; - unsigned long args[2]; + unsigned long args[LTTNG_SYSCALL_NR_ARGS]; - syscall_get_arguments(current, regs, 0, entry->nrargs, args); + lttng_syscall_get_arguments(current, regs, args); fptr(event, args[0], args[1]); break; } @@ -455,9 +456,9 @@ void syscall_entry_probe(void *__data, struct pt_regs *regs, long id) unsigned long arg0, unsigned long arg1, unsigned long arg2) = entry->func; - unsigned long args[3]; + unsigned long args[LTTNG_SYSCALL_NR_ARGS]; - syscall_get_arguments(current, regs, 0, entry->nrargs, args); + lttng_syscall_get_arguments(current, regs, args); fptr(event, args[0], args[1], args[2]); break; } @@ -468,9 +469,9 @@ void syscall_entry_probe(void *__data, struct pt_regs *regs, long id) unsigned long arg1, unsigned long arg2, unsigned long arg3) = entry->func; - unsigned long args[4]; + unsigned long args[LTTNG_SYSCALL_NR_ARGS]; - syscall_get_arguments(current, regs, 0, entry->nrargs, args); + lttng_syscall_get_arguments(current, regs, args); fptr(event, args[0], args[1], args[2], args[3]); break; } @@ -482,9 +483,9 @@ void syscall_entry_probe(void *__data, struct pt_regs *regs, long id) unsigned long arg2, unsigned long arg3, unsigned long arg4) = entry->func; - unsigned long args[5]; + unsigned long args[LTTNG_SYSCALL_NR_ARGS]; - syscall_get_arguments(current, regs, 0, entry->nrargs, args); + lttng_syscall_get_arguments(current, regs, args); fptr(event, args[0], args[1], args[2], args[3], args[4]); break; } @@ -497,9 +498,9 @@ void syscall_entry_probe(void *__data, struct pt_regs *regs, long id) unsigned long arg3, unsigned long arg4, unsigned long arg5) = entry->func; - unsigned long args[6]; + unsigned long args[LTTNG_SYSCALL_NR_ARGS]; - syscall_get_arguments(current, regs, 0, entry->nrargs, args); + lttng_syscall_get_arguments(current, regs, args); fptr(event, args[0], args[1], args[2], args[3], args[4], args[5]); break; @@ -512,9 +513,9 @@ void syscall_entry_probe(void *__data, struct pt_regs *regs, long id) static void syscall_exit_unknown(struct lttng_event *event, struct pt_regs *regs, int id, long ret) { - unsigned long args[UNKNOWN_SYSCALL_NRARGS]; + unsigned long args[LTTNG_SYSCALL_NR_ARGS]; - syscall_get_arguments(current, regs, 0, UNKNOWN_SYSCALL_NRARGS, args); + lttng_syscall_get_arguments(current, regs, args); if (unlikely(in_compat_syscall())) __event_probe__compat_syscall_exit_unknown(event, id, ret, args); @@ -588,9 +589,9 @@ void syscall_exit_probe(void *__data, struct pt_regs *regs, long ret) void (*fptr)(void *__data, long ret, unsigned long arg0) = entry->func; - unsigned long args[1]; + unsigned long args[LTTNG_SYSCALL_NR_ARGS]; - syscall_get_arguments(current, regs, 0, entry->nrargs, args); + lttng_syscall_get_arguments(current, regs, args); fptr(event, ret, args[0]); break; } @@ -600,9 +601,9 @@ void syscall_exit_probe(void *__data, struct pt_regs *regs, long ret) long ret, unsigned long arg0, unsigned long arg1) = entry->func; - unsigned long args[2]; + unsigned long args[LTTNG_SYSCALL_NR_ARGS]; - syscall_get_arguments(current, regs, 0, entry->nrargs, args); + lttng_syscall_get_arguments(current, regs, args); fptr(event, ret, args[0], args[1]); break; } @@ -613,9 +614,9 @@ void syscall_exit_probe(void *__data, struct pt_regs *regs, long ret) unsigned long arg0, unsigned long arg1, unsigned long arg2) = entry->func; - unsigned long args[3]; + unsigned long args[LTTNG_SYSCALL_NR_ARGS]; - syscall_get_arguments(current, regs, 0, entry->nrargs, args); + lttng_syscall_get_arguments(current, regs, args); fptr(event, ret, args[0], args[1], args[2]); break; } @@ -627,9 +628,9 @@ void syscall_exit_probe(void *__data, struct pt_regs *regs, long ret) unsigned long arg1, unsigned long arg2, unsigned long arg3) = entry->func; - unsigned long args[4]; + unsigned long args[LTTNG_SYSCALL_NR_ARGS]; - syscall_get_arguments(current, regs, 0, entry->nrargs, args); + lttng_syscall_get_arguments(current, regs, args); fptr(event, ret, args[0], args[1], args[2], args[3]); break; } @@ -642,9 +643,9 @@ void syscall_exit_probe(void *__data, struct pt_regs *regs, long ret) unsigned long arg2, unsigned long arg3, unsigned long arg4) = entry->func; - unsigned long args[5]; + unsigned long args[LTTNG_SYSCALL_NR_ARGS]; - syscall_get_arguments(current, regs, 0, entry->nrargs, args); + lttng_syscall_get_arguments(current, regs, args); fptr(event, ret, args[0], args[1], args[2], args[3], args[4]); break; } @@ -658,9 +659,9 @@ void syscall_exit_probe(void *__data, struct pt_regs *regs, long ret) unsigned long arg3, unsigned long arg4, unsigned long arg5) = entry->func; - unsigned long args[6]; + unsigned long args[LTTNG_SYSCALL_NR_ARGS]; - syscall_get_arguments(current, regs, 0, entry->nrargs, args); + lttng_syscall_get_arguments(current, regs, args); fptr(event, ret, args[0], args[1], args[2], args[3], args[4], args[5]); break; diff --git a/wrapper/syscall.h b/wrapper/syscall.h new file mode 100644 index 00000000..8715f0c5 --- /dev/null +++ b/wrapper/syscall.h @@ -0,0 +1,34 @@ +/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1) + * + * wrapper/syscall.h + * + * wrapper around asm/syscall.h. + * + * Copyright (C) 2019 Michael Jeanson + */ + +#ifndef _LTTNG_WRAPPER_SYSCALL_H +#define _LTTNG_WRAPPER_SYSCALL_H + +#include +#include + +#define LTTNG_SYSCALL_NR_ARGS 6 + +#if (LINUX_VERSION_CODE >= KERNEL_VERSION(5,1,0)) + +#define lttng_syscall_get_arguments(task, regs, args) \ + syscall_get_arguments(task, regs, args) + +#else /* LINUX_VERSION_CODE >= KERNEL_VERSION(5,1,0) */ + +static inline +void lttng_syscall_get_arguments(struct task_struct *task, + struct pt_regs *regs, unsigned long *args) +{ + syscall_get_arguments(task, regs, 0, LTTNG_SYSCALL_NR_ARGS, args); +} + +#endif /* LINUX_VERSION_CODE >= KERNEL_VERSION(5,1,0) */ + +#endif /* _LTTNG_WRAPPER_SYSCALL_H */ -- 2.34.1