[PATCH v3] ARM: support syscall tracing
Wade Farnsworth
wade_farnsworth at mentor.com
Mon Aug 20 10:38:37 EDT 2012
As specified by ftrace-design.txt, TIF_SYSCALL_TRACEPOINT was
added, as well as NR_syscalls in asm/unistd.h. Additionally,
syscall_trace_{enter,exit} were modified to call trace_sys_{enter,exit}
as appropriate.
Tests #2 - #4 of "perf test" now complete successfully.
Signed-off-by: Steven Walter <stevenrwalter at gmail.com>
Signed-off-by: Wade Farnsworth <wade_farnsworth at mentor.com>
---
This patch is an update of one I posted some months ago. It has been
rebased to Linus's current master branch.
- v2: Implemented changes suggested by Will:
- Folded _TIF_SYSCALL_TRACEPOINT into _TIF_SYSCALL_WORK to save an
instruction in entry-common.S.
- Moved calls to trace_sys_{enter,exit} to syscall_trace_{enter,exit}
- v3:
- Set current_thread_info()->syscall before checking TIF_SYSCALL_TRACE.
- Pass the original syscall number into trace_sys_{enter,exit}, not
the return value from ptrace_syscall_trace().
arch/arm/Kconfig | 1 +
arch/arm/include/asm/syscall.h | 4 ++++
arch/arm/include/asm/thread_info.h | 4 +++-
arch/arm/include/asm/unistd.h | 8 ++++++++
arch/arm/kernel/entry-common.S | 11 ++++++++++-
arch/arm/kernel/ptrace.c | 11 +++++++++--
6 files changed, 35 insertions(+), 4 deletions(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index e91c7cd..983e9eb 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -16,6 +16,7 @@ config ARM
select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL
select HAVE_ARCH_KGDB
select HAVE_ARCH_TRACEHOOK
+ select HAVE_SYSCALL_TRACEPOINTS
select HAVE_KPROBES if !XIP_KERNEL
select HAVE_KRETPROBES if (HAVE_KPROBES)
select HAVE_FUNCTION_TRACER if (!XIP_KERNEL)
diff --git a/arch/arm/include/asm/syscall.h b/arch/arm/include/asm/syscall.h
index c334a23..47486a4 100644
--- a/arch/arm/include/asm/syscall.h
+++ b/arch/arm/include/asm/syscall.h
@@ -9,6 +9,10 @@
#include <linux/err.h>
+#include <asm/unistd.h>
+
+#define NR_syscalls (__NR_syscalls)
+
extern const unsigned long sys_call_table[];
static inline int syscall_get_nr(struct task_struct *task,
diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h
index af7b0bd..5ded667 100644
--- a/arch/arm/include/asm/thread_info.h
+++ b/arch/arm/include/asm/thread_info.h
@@ -148,6 +148,7 @@ extern int vfp_restore_user_hwstate(struct user_vfp __user *,
#define TIF_NOTIFY_RESUME 2 /* callback before returning to user */
#define TIF_SYSCALL_TRACE 8
#define TIF_SYSCALL_AUDIT 9
+#define TIF_SYSCALL_TRACEPOINT 10
#define TIF_POLLING_NRFLAG 16
#define TIF_USING_IWMMXT 17
#define TIF_MEMDIE 18 /* is terminating due to OOM killer */
@@ -160,12 +161,13 @@ extern int vfp_restore_user_hwstate(struct user_vfp __user *,
#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
+#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
#define _TIF_USING_IWMMXT (1 << TIF_USING_IWMMXT)
#define _TIF_SECCOMP (1 << TIF_SECCOMP)
/* Checks for any syscall work in entry-common.S */
-#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT)
+#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SYSCALL_TRACEPOINT)
/*
* Change these and you break ASM code in entry-common.S
diff --git a/arch/arm/include/asm/unistd.h b/arch/arm/include/asm/unistd.h
index 0cab47d..a566ec2 100644
--- a/arch/arm/include/asm/unistd.h
+++ b/arch/arm/include/asm/unistd.h
@@ -406,6 +406,14 @@
#define __NR_process_vm_writev (__NR_SYSCALL_BASE+377)
/*
+ * This may need to be greater than __NR_last_syscall+1 in order to
+ * account for the padding in the syscall table
+ */
+#ifdef __KERNEL__
+#define __NR_syscalls (380)
+#endif /* __KERNEL__ */
+
+/*
* The following SWIs are ARM private.
*/
#define __ARM_NR_BASE (__NR_SYSCALL_BASE+0x0f0000)
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 978eac5..b032c94 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -94,6 +94,15 @@ ENDPROC(ret_from_fork)
.equ NR_syscalls,0
#define CALL(x) .equ NR_syscalls,NR_syscalls+1
#include "calls.S"
+
+/*
+ * Ensure that the system call table is equal to __NR_syscalls,
+ * which is the value the rest of the system sees
+ */
+.ifne NR_syscalls - __NR_syscalls
+.error "__NR_syscalls is not equal to the size of the syscall table"
+.endif
+
#undef CALL
#define CALL(x) .long x
@@ -415,7 +424,7 @@ local_restart:
1:
#endif
- tst r10, #_TIF_SYSCALL_WORK @ are we tracing syscalls?
+ tst r10, #_TIF_SYSCALL_WORK @ are we tracing syscalls?
bne __sys_trace
cmp scno, #NR_syscalls @ check upper syscall limit
diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c
index 3e0fc5f..4974cdf 100644
--- a/arch/arm/kernel/ptrace.c
+++ b/arch/arm/kernel/ptrace.c
@@ -30,6 +30,9 @@
#include <asm/pgtable.h>
#include <asm/traps.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/syscalls.h>
+
#define REG_PC 15
#define REG_PSR 16
/*
@@ -918,11 +921,11 @@ static int ptrace_syscall_trace(struct pt_regs *regs, int scno,
{
unsigned long ip;
+ current_thread_info()->syscall = scno;
+
if (!test_thread_flag(TIF_SYSCALL_TRACE))
return scno;
- current_thread_info()->syscall = scno;
-
/*
* IP is used to denote syscall entry/exit:
* IP = 0 -> entry, =1 -> exit
@@ -942,6 +945,8 @@ static int ptrace_syscall_trace(struct pt_regs *regs, int scno,
asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno)
{
int ret = ptrace_syscall_trace(regs, scno, PTRACE_SYSCALL_ENTER);
+ if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
+ trace_sys_enter(regs, scno);
audit_syscall_entry(AUDIT_ARCH_ARM, scno, regs->ARM_r0, regs->ARM_r1,
regs->ARM_r2, regs->ARM_r3);
return ret;
@@ -950,6 +955,8 @@ asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno)
asmlinkage int syscall_trace_exit(struct pt_regs *regs, int scno)
{
int ret = ptrace_syscall_trace(regs, scno, PTRACE_SYSCALL_EXIT);
+ if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
+ trace_sys_exit(regs, scno);
audit_syscall_exit(regs);
return ret;
}
--
1.7.0.4
More information about the linux-arm-kernel
mailing list