[lttng-dev] [PATCH lttng-modules] RFC: fix: Remove start and number from syscall_get_arguments() args (v5.1)
Michael Jeanson
mjeanson at efficios.com
Tue Apr 9 14:12:41 EDT 2019
commit b35f549df1d7520d37ba1e6d4a8d4df6bd52d136
Author: Steven Rostedt (Red Hat) <rostedt at goodmis.org>
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 <mjeanson at efficios.com>
---
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 bcc06b5..ebd9246 100644
--- a/lttng-syscalls.c
+++ b/lttng-syscalls.c
@@ -25,6 +25,7 @@
#include <wrapper/tracepoint.h>
#include <wrapper/file.h>
#include <wrapper/rcu.h>
+#include <wrapper/syscall.h>
#include <lttng-events.h>
#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 0000000..8715f0c
--- /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 <mjeanson at efficios.com>
+ */
+
+#ifndef _LTTNG_WRAPPER_SYSCALL_H
+#define _LTTNG_WRAPPER_SYSCALL_H
+
+#include <asm/syscall.h>
+#include <lttng-kernel-version.h>
+
+#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 */
--
2.17.1
More information about the lttng-dev
mailing list