[PATCH v4 3/3] ARM: support syscall tracing
Wade Farnsworth
wade_farnsworth at mentor.com
Fri Mar 23 10:53:15 EDT 2012
As specified by ftrace-design.txt, TIF_SYSCALL_TRACEPOINT was
added, as well as NR_syscalls in asm/unistd.h. Additionally,
__sys_trace was modified to call trace_sys_enter and
trace_sys_exit when 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>
Reviewed-by: Will Deacon <will.deacon at arm.com>
---
arch/arm/Kconfig | 1 +
arch/arm/include/asm/syscall.h | 4 ++++
arch/arm/include/asm/thread_info.h | 2 ++
arch/arm/include/asm/unistd.h | 8 ++++++++
arch/arm/kernel/entry-common.S | 18 ++++++++++++++++--
arch/arm/kernel/ptrace.c | 23 ++++++++++++++++++-----
6 files changed, 49 insertions(+), 7 deletions(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index c87e23f..5603715 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -11,6 +11,7 @@ config ARM
select HAVE_OPROFILE if (HAVE_PERF_EVENTS)
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 d4c24d4..f2ff2de 100644
--- a/arch/arm/include/asm/thread_info.h
+++ b/arch/arm/include/asm/thread_info.h
@@ -146,6 +146,7 @@ extern void vfp_flush_hwstate(struct thread_info *);
#define TIF_MEMDIE 18 /* is terminating due to OOM killer */
#define TIF_RESTORE_SIGMASK 20
#define TIF_SECCOMP 21
+#define TIF_SYSCALL_TRACEPOINT 22
#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
@@ -156,6 +157,7 @@ extern void vfp_flush_hwstate(struct thread_info *);
#define _TIF_USING_IWMMXT (1 << TIF_USING_IWMMXT)
#define _TIF_RESTORE_SIGMASK (1 << TIF_RESTORE_SIGMASK)
#define _TIF_SECCOMP (1 << TIF_SECCOMP)
+#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
/* Checks for any syscall work in entry-common.S */
#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT)
diff --git a/arch/arm/include/asm/unistd.h b/arch/arm/include/asm/unistd.h
index 512cd14..d27d7d7 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 9fd0ba9..3df0ca3 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -79,6 +79,11 @@ no_work_pending:
ENDPROC(ret_to_user_from_irq)
ENDPROC(ret_to_user)
+.macro test_syscall_tracing reg
+ tst \reg, #_TIF_SYSCALL_WORK
+ tsteq \reg, #_TIF_SYSCALL_TRACEPOINT
+.endm
+
/*
* This is how we return from a fork.
*/
@@ -87,7 +92,7 @@ ENTRY(ret_from_fork)
get_thread_info tsk
ldr r1, [tsk, #TI_FLAGS] @ check for syscall tracing
mov why, #1
- tst r1, #_TIF_SYSCALL_WORK @ are we tracing syscalls?
+ test_syscall_tracing r1
beq ret_slow_syscall
mov r1, sp
mov r0, #1 @ trace exit [IP = 1]
@@ -98,6 +103,15 @@ 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
@@ -446,7 +460,7 @@ ENTRY(vector_swi)
1:
#endif
- tst r10, #_TIF_SYSCALL_WORK @ are we tracing syscalls?
+ test_syscall_tracing r10
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 46f4b41..dbbf4ce 100644
--- a/arch/arm/kernel/ptrace.c
+++ b/arch/arm/kernel/ptrace.c
@@ -30,6 +30,9 @@
#include <asm/system.h>
#include <asm/traps.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/syscalls.h>
+
#define REG_PC 15
#define REG_PSR 16
/*
@@ -929,15 +932,25 @@ asmlinkage int syscall_trace(int why, struct pt_regs *regs, int scno)
audit_syscall_entry(AUDIT_ARCH_NR, scno, regs->ARM_r0,
regs->ARM_r1, regs->ARM_r2, regs->ARM_r3);
- if (!test_thread_flag(TIF_SYSCALL_TRACE))
+ if (!test_thread_flag(TIF_SYSCALL_TRACE) &&
+ !test_thread_flag(TIF_SYSCALL_TRACEPOINT))
return scno;
current_thread_info()->syscall = scno;
- if (why)
- tracehook_report_syscall_exit(regs, 0);
- else if (tracehook_report_syscall_entry(regs))
- current_thread_info()->syscall = -1;
+ if (test_thread_flag(TIF_SYSCALL_TRACE)) {
+ if (why)
+ tracehook_report_syscall_exit(regs, 0);
+ else if (tracehook_report_syscall_entry(regs))
+ current_thread_info()->syscall = -1;
+ }
+
+ if (test_thread_flag(TIF_SYSCALL_TRACEPOINT)) {
+ if (why)
+ trace_sys_exit(regs, scno);
+ else
+ trace_sys_enter(regs, scno);
+ }
regs->ARM_ip = ip;
--
1.7.0.4
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