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ARM support for syscall tracing

PATCH Superseded Wade Farnsworth 2 participants 22 messages Feb 22, 2012 – Mar 30, 2012

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Arm (32-bit) ptrace support
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Wade Farnsworth

author
#0 lore raw

cover ARM support for syscall tracing

This is a rework of Steven Walter's syscall tracing patches first posted here:

http://lists.infradead.org/pipermail/linux-arm-kernel/2011-November/074454.html

I've rebased the patches against the current mainline master branch, as well as implemented several changes based on feedback from Will Deacon and Russel King.

Wade Farnsworth (3):
ARM: add support for the generic syscall.h interface
ARM: add TRACEHOOK support
ARM: support syscall tracing

 arch/arm/Kconfig                   |    2 +
 arch/arm/include/asm/ptrace.h      |    5 ++
 arch/arm/include/asm/syscall.h     |   93 ++++++++++++++++++++++++++++++++++++
 arch/arm/include/asm/thread_info.h |    2 +
 arch/arm/include/asm/unistd.h      |   12 +++++
 arch/arm/kernel/entry-common.S     |   16 +++++-
 arch/arm/kernel/ptrace.c           |   34 +++++++------
 arch/arm/kernel/signal.c           |    2 +
 8 files changed, 149 insertions(+), 17 deletions(-)
 create mode 100644 arch/arm/include/asm/syscall.h
author
#1 lore raw

PATCH 1/3 ARM: add support for the generic syscall.h interface

Supplying the asm-generic/syscall.h interface is a pre-requisite for HAVE_ARCH_TRACEHOOK

Signed-off-by Steven Walter <[email protected]>
Signed-off-by Wade Farnsworth <[email protected]>
---
 arch/arm/include/asm/syscall.h |   93 ++++++++++++++++++++++++++++++++++++++++
 1 files changed, 93 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm/include/asm/syscall.h
arch/arm/include/asm/syscall.h new file +93 -0
new file mode 100644
index 0000000..d5e30ef
@@ -0,0 +1,93 @@
+/*
+ * Access to user system call parameters and results
+ *
+ * See asm-generic/syscall.h for descriptions of what we must do here.
+ */
+
+#ifndef _ASM_ARM_SYSCALL_H
+#define _ASM_ARM_SYSCALL_H
+
+#include <linux/err.h>
+
+extern const unsigned long sys_call_table[];
+
+static inline int syscall_get_nr(struct task_struct *task,
+				 struct pt_regs *regs)
+{
+	return task_thread_info(task)->syscall;
+}
+
+static inline void syscall_rollback(struct task_struct *task,
+				    struct pt_regs *regs)
+{
+	regs->ARM_r0 = regs->ARM_ORIG_r0;
+}
+
+static inline long syscall_get_error(struct task_struct *task,
+				     struct pt_regs *regs)
+{
+	unsigned long error = regs->ARM_r0;
+	return IS_ERR_VALUE(error) ? error : 0;
+}
+
+static inline long syscall_get_return_value(struct task_struct *task,
+					    struct pt_regs *regs)
+{
+	return regs->ARM_r0;
+}
+
+static inline void syscall_set_return_value(struct task_struct *task,
+					    struct pt_regs *regs,
+					    int error, long val)
+{
+	regs->ARM_r0 = (long) error ?: val;
+}
+
+#define SYSCALL_MAX_ARGS 7
+
+static inline void syscall_get_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 unsigned int i, unsigned int n,
+					 unsigned long *args)
+{
+	if (i + n > SYSCALL_MAX_ARGS) {
+		unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i;
+		unsigned int n_bad = n + i - SYSCALL_MAX_ARGS;
+		pr_warning("%s called with max args %d, handling only %d\n",
+			   __func__, i + n, SYSCALL_MAX_ARGS);
+		memset(args_bad, 0, n_bad * sizeof(args[0]));
+		n = SYSCALL_MAX_ARGS - i;
+	}
+
+	if (i == 0) {
+		args[0] = regs->ARM_ORIG_r0;
+		args++;
+		i++;
+		n--;
+	}
+
+	memcpy(args, &regs->ARM_r0 + i, n * sizeof(args[0]));
+}
+
+static inline void syscall_set_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 unsigned int i, unsigned int n,
+					 const unsigned long *args)
+{
+	if (i + n > SYSCALL_MAX_ARGS) {
+		pr_warning("%s called with max args %d, handling only %d\n",
+			   __func__, i + n, SYSCALL_MAX_ARGS);
+		n = SYSCALL_MAX_ARGS - i;
+	}
+
+	if (i == 0) {
+		regs->ARM_ORIG_r0 = args[0];
+		args++;
+		i++;
+		n--;
+	}
+
+	memcpy(&regs->ARM_r0 + i, args, n * sizeof(args[0]));
+}
+
+#endif /* _ASM_ARM_SYSCALL_H */
Signature · 1 line
1.7.0.4
#2 lore raw

PATCH v2 1/3 ARM: add support for the generic syscall.h interface

Hi Wade,

Quoted 9 lines · Wade Farnsworth

Supplying the asm-generic/syscall.h interface is a pre-requisite for HAVE_ARCH_TRACEHOOK

Signed-off-by Steven Walter <[email protected]>
Signed-off-by Wade Farnsworth <[email protected]>
---
 arch/arm/include/asm/syscall.h |   93 ++++++++++++++++++++++++++++++++++++++++
 1 files changed, 93 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm/include/asm/syscall.h

[...]

arch/arm/include/asm/syscall.h line 44

Quoted 7 lines
arch/arm/include/asm/syscall.h new file +7 -0
+
+static inline void syscall_set_return_value(struct task_struct *task,
+					    struct pt_regs *regs,
+					    int error, long val)
+{
+	regs->ARM_r0 = (long) error ?: val;
+}

This looks like far too much fun for kernel code, although I see that '?:' does appear elsewhere in the kernel. Usually in perl regexs though :)

Will

author
#3 lore raw

PATCH 1/3 ARM: add support for the generic syscall.h interface

Quoted 15 lines · Will Deacon

Hi Wade,

Quoted 9 lines · Wade Farnsworth

Supplying the asm-generic/syscall.h interface is a pre-requisite for HAVE_ARCH_TRACEHOOK

Signed-off-by Steven Walter<[email protected]>
Signed-off-by Wade Farnsworth<[email protected]>
---
  arch/arm/include/asm/syscall.h |   93 ++++++++++++++++++++++++++++++++++++++++
  1 files changed, 93 insertions(+), 0 deletions(-)

create mode 100644 arch/arm/include/asm/syscall.h

[...]

Quoted 11 lines

arch/arm/include/asm/syscall.h line 44

Quoted 7 lines
arch/arm/include/asm/syscall.h new file +7 -0
+
+static inline void syscall_set_return_value(struct task_struct *task,
+					    struct pt_regs *regs,
+					    int error, long val)
+{
+	regs->ARM_r0 = (long) error ?: val;
+}

This looks like far too much fun for kernel code, although I see that '?:' does appear elsewhere in the kernel. Usually in perl regexs though :)

OK, I'll change this to

regs->ARM_r0 = (long) error ? error : val;

That better? :)

Thanks,

-Wade

author
#4 lore raw

PATCH 2/3 ARM: add TRACEHOOK support

In reply to Wade Farnsworth

Add calls to tracehook_report_syscall_{entry,exit} and tracehook_signal_handler

Signed-off-by Steven Walter <[email protected]>
Signed-off-by Wade Farnsworth <[email protected]>
---
 arch/arm/Kconfig              |    1 +
 arch/arm/include/asm/ptrace.h |    5 +++++
 arch/arm/kernel/ptrace.c      |   21 ++++++---------------
 arch/arm/kernel/signal.c      |    2 ++
 4 files changed, 14 insertions(+), 15 deletions(-)
arch/arm/Kconfig +1 -0
index a48aecc..0faad0c 100644
@@ -10,6 +10,7 @@ config ARM
 	select GENERIC_ATOMIC64 if (CPU_V6 || !CPU_32v6K || !AEABI)
 	select HAVE_OPROFILE if (HAVE_PERF_EVENTS)
 	select HAVE_ARCH_KGDB
+	select HAVE_ARCH_TRACEHOOK
 	select HAVE_KPROBES if !XIP_KERNEL
 	select HAVE_KRETPROBES if (HAVE_KPROBES)
 	select HAVE_FUNCTION_TRACER if (!XIP_KERNEL)
arch/arm/include/asm/ptrace.h +5 -0
index 451808b..355ece5 100644
@@ -249,6 +249,11 @@ static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
 	return regs->ARM_sp;
 }
 
+static inline unsigned long user_stack_pointer(struct pt_regs *regs)
+{
+	return regs->ARM_sp;
+}
+
 #endif /* __KERNEL__ */
 
 #endif /* __ASSEMBLY__ */
arch/arm/kernel/ptrace.c +6 -15
index e33870f..5cc5415 100644
@@ -23,6 +23,7 @@
 #include <linux/perf_event.h>
 #include <linux/hw_breakpoint.h>
 #include <linux/regset.h>
+#include <linux/tracehook.h>
 
 #include <asm/pgtable.h>
 #include <asm/system.h>

@@ -923,24 +924,14 @@ asmlinkage int syscall_trace(int why, struct pt_regs *regs, int scno)
 
 	if (!test_thread_flag(TIF_SYSCALL_TRACE))
 		return scno;
-	if (!(current->ptrace & PT_PTRACED))
-		return scno;
 
 	current_thread_info()->syscall = scno;
 
-	/* the 0x80 provides a way for the tracing parent to distinguish
-	   between a syscall stop and SIGTRAP delivery */
-	ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
-				 ? 0x80 : 0));
-	/*
-	 * this isn't the same as continuing with a signal, but it will do
-	 * for normal use.  strace only continues with a signal if the
-	 * stopping signal is not SIGTRAP.  -brl
-	 */
-	if (current->exit_code) {
-		send_sig(current->exit_code, current, 1);
-		current->exit_code = 0;
-	}
+	if (why)
+		tracehook_report_syscall_exit(regs, 0);
+	else if (tracehook_report_syscall_entry(regs))
+		current_thread_info()->syscall = -1;
+
 	regs->ARM_ip = ip;
 
 	return current_thread_info()->syscall;
arch/arm/kernel/signal.c +2 -0
index 9e617bd..6f084c1 100644
@@ -644,6 +644,8 @@ handle_signal(unsigned long sig, struct k_sigaction *ka,
 	recalc_sigpending();
 	spin_unlock_irq(&tsk->sighand->siglock);
 
+	tracehook_signal_handler(sig, info, ka, regs, 0);
+
 	return 0;
 }
Signature · 1 line
1.7.0.4
author
#5 lore raw

PATCH 3/3 ARM: support syscall tracing

In reply to Wade Farnsworth

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 <[email protected]>
Signed-off-by Wade Farnsworth <[email protected]>
---
 arch/arm/Kconfig                   |    1 +
 arch/arm/include/asm/thread_info.h |    2 ++
 arch/arm/include/asm/unistd.h      |   12 ++++++++++++
 arch/arm/kernel/entry-common.S     |   16 ++++++++++++++--
 arch/arm/kernel/ptrace.c           |   23 ++++++++++++++++++-----
 5 files changed, 47 insertions(+), 7 deletions(-)
arch/arm/Kconfig +1 -0
index 0faad0c..b1d9396 100644
@@ -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)
arch/arm/include/asm/thread_info.h +2 -0
index d4c24d4..f2ff2de 100644
@@ -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)
arch/arm/include/asm/unistd.h +12 -0
index 512cd14..e4a2e78 100644
@@ -405,6 +405,18 @@
 #define __NR_process_vm_readv		(__NR_SYSCALL_BASE+376)
 #define __NR_process_vm_writev		(__NR_SYSCALL_BASE+377)
 
+#ifdef __KERNEL__
+
+/* This may need to be greater than __NR_last_syscall+1 in order to
+ * account for the padding in the syscall table */
+#define __NR_syscalls  (380)
+
+#ifndef __ASSEMBLY__
+#define NR_syscalls (__NR_syscalls)
+#endif /* __ASSEMBLY__ */
+
+#endif /* __KERNEL__ */
+
 /*
  * The following SWIs are ARM private.
  */
arch/arm/kernel/entry-common.S +14 -2
index 9fd0ba9..9bed212 100644
@@ -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 +103,13 @@ 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 not larger than __NR_syscalls,
+ * which is the value the rest of the system sees */
+.ifgt NR_syscalls - __NR_syscalls
+.error "__NR_syscalls is less than the size of the syscall table"
+.endif
+
 #undef CALL
 #define CALL(x) .long x
 

@@ -446,7 +458,7 @@ 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
arch/arm/kernel/ptrace.c +18 -5
index 5cc5415..5e15e67 100644
@@ -29,6 +29,9 @@
 #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
 /*

@@ -922,15 +925,25 @@ asmlinkage int syscall_trace(int why, struct pt_regs *regs, int scno)
 		audit_syscall_entry(AUDIT_ARCH_ARMEB, 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;
Signature · 1 line
1.7.0.4
#6 lore raw

PATCH v2 3/3 ARM: support syscall tracing

Quoted 10 lines · Wade Farnsworth

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 <[email protected]>
Signed-off-by Wade Farnsworth <[email protected]>

---

[...]

arch/arm/include/asm/unistd.h line 412

Quoted 13 lines
arch/arm/include/asm/unistd.h +5 -0
index 512cd14..e4a2e78 100644
@@ -405,6 +405,18 @@
 #define __NR_process_vm_readv		(__NR_SYSCALL_BASE+376)
 #define __NR_process_vm_writev		(__NR_SYSCALL_BASE+377)
 
+#ifdef __KERNEL__
+
+/* This may need to be greater than __NR_last_syscall+1 in order to
+ * account for the padding in the syscall table */
+#define __NR_syscalls  (380)

Do we actually have padding in the syscall table? It looks like a list of .long to me. I'd rather put the correct number in if possible.

arch/arm/include/asm/unistd.h line 416

Quoted 3 lines
arch/arm/include/asm/unistd.h +3 -0
+#ifndef __ASSEMBLY__
+#define NR_syscalls (__NR_syscalls)
+#endif /* __ASSEMBLY__ */

Hmm, these guards feel like a hack. Would moving the define into syscall.h help?

Quoted 26 lines
arch/arm/kernel/entry-common.S +6 -1
index 9fd0ba9..9bed212 100644
@@ -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]

arch/arm/kernel/entry-common.S ENDPROC(ret_from_fork) · line 111

Quoted 9 lines
arch/arm/kernel/entry-common.S +6 -0
@@ -98,6 +103,13 @@ 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 not larger than __NR_syscalls,
+ * which is the value the rest of the system sees */
+.ifgt NR_syscalls - __NR_syscalls
+.error "__NR_syscalls is less than the size of the syscall table"
+.endif

I think it would also be nice to check for equality here if we can.

Rest of the code looks alright, but it should be tested with OABI if it hasn't been already.

Will

author
#7 lore raw

PATCH 3/3 ARM: support syscall tracing

Quoted 22 lines · Will Deacon
Quoted 10 lines · Wade Farnsworth

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<[email protected]>
Signed-off-by Wade Farnsworth<[email protected]>

---

[...]

Quoted 8 lines
arch/arm/include/asm/unistd.h +0 -0
index 512cd14..e4a2e78 100644
@@ -405,6 +405,18 @@
  #define __NR_process_vm_readv		(__NR_SYSCALL_BASE+376)
  #define __NR_process_vm_writev		(__NR_SYSCALL_BASE+377)
Quoted 8 lines

arch/arm/include/asm/unistd.h line 412

Quoted 5 lines
arch/arm/include/asm/unistd.h +5 -0
+#ifdef __KERNEL__
+
+/* This may need to be greater than __NR_last_syscall+1 in order to
+ * account for the padding in the syscall table */
+#define __NR_syscalls  (380)

Do we actually have padding in the syscall table? It looks like a list of .long to me. I'd rather put the correct number in if possible.

This patch will calculate NR_syscalls by counting the number of entries in calls.S. calls.S may add up to three entries of padding at the end of that file that __NR_syscalls needs to account for.

Quoted 7 lines

arch/arm/include/asm/unistd.h line 416

Quoted 4 lines
arch/arm/include/asm/unistd.h +3 -0
+#ifndef __ASSEMBLY__
+#define NR_syscalls (__NR_syscalls)
+#endif /* __ASSEMBLY__ */

Hmm, these guards feel like a hack. Would moving the define into syscall.h help?

I'll give this a shot, though I'll also note that adding the guards on !__ASSEMBLY__ was suggested by Russel:

http://lists.infradead.org/pipermail/linux-arm-kernel/2011-November/074506.html

Quoted 30 lines
Quoted 30 lines
arch/arm/kernel/entry-common.S +6 -1
index 9fd0ba9..9bed212 100644
@@ -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 +103,13 @@ ENDPROC(ret_from_fork)
  	.equ NR_syscalls,0
  #define CALL(x) .equ NR_syscalls,NR_syscalls+1
  #include "calls.S"
Quoted 8 lines

arch/arm/kernel/entry-common.S ENDPROC(ret_from_fork) · line 111

Quoted 6 lines
arch/arm/kernel/entry-common.S +6 -0
+
+/* Ensure that the system call table is not larger than __NR_syscalls,
+ * which is the value the rest of the system sees */
+.ifgt NR_syscalls - __NR_syscalls
+.error "__NR_syscalls is less than the size of the syscall table"
+.endif

I think it would also be nice to check for equality here if we can.

Should be doable.

Quoted 4 lines

Rest of the code looks alright, but it should be tested with OABI if it hasn't been already.

I might be able to build my userspace against OABI. I'll see what I can dig up.

Thanks for the review!

-Wade

author
#8 lore raw

v2 cover ARM support for syscall tracing

In reply to Wade Farnsworth

This is a rework of Steven Walter's syscall tracing patches first posted here:

http://lists.infradead.org/pipermail/linux-arm-kernel/2011-November/074454.html

I've rebased the patches against the current mainline master branch, as well as implemented several changes based on feedback from Will Deacon and Russel King.

v2: - Tested on EABI and OABI.
- Removed an instance of the ?: operator in syscall_set_return_value()
- Moved #define of NR_syscalls to syscall.h
- Changed the test of NR_syscalls vs __NR_syscalls in entry-common.S to .ifne

Wade Farnsworth (3):
ARM: add support for the generic syscall.h interface
ARM: add TRACEHOOK support
ARM: support syscall tracing

 arch/arm/Kconfig                   |    2 +
 arch/arm/include/asm/ptrace.h      |    5 ++
 arch/arm/include/asm/syscall.h     |   97 ++++++++++++++++++++++++++++++++++++
 arch/arm/include/asm/thread_info.h |    2 +
 arch/arm/include/asm/unistd.h      |    8 +++
 arch/arm/kernel/entry-common.S     |   16 +++++-
 arch/arm/kernel/ptrace.c           |   34 +++++++------
 arch/arm/kernel/signal.c           |    2 +
 8 files changed, 149 insertions(+), 17 deletions(-)
 create mode 100644 arch/arm/include/asm/syscall.h
author
#9 lore raw

PATCH v2 1/3 ARM: add support for the generic syscall.h interface

Supplying the asm-generic/syscall.h interface is a pre-requisite for HAVE_ARCH_TRACEHOOK

Signed-off-by Steven Walter <[email protected]>
Signed-off-by Wade Farnsworth <[email protected]>
---
 arch/arm/include/asm/syscall.h |   93 ++++++++++++++++++++++++++++++++++++++++
 1 files changed, 93 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm/include/asm/syscall.h
arch/arm/include/asm/syscall.h new file +93 -0
new file mode 100644
index 0000000..c334a23
@@ -0,0 +1,93 @@
+/*
+ * Access to user system call parameters and results
+ *
+ * See asm-generic/syscall.h for descriptions of what we must do here.
+ */
+
+#ifndef _ASM_ARM_SYSCALL_H
+#define _ASM_ARM_SYSCALL_H
+
+#include <linux/err.h>
+
+extern const unsigned long sys_call_table[];
+
+static inline int syscall_get_nr(struct task_struct *task,
+				 struct pt_regs *regs)
+{
+	return task_thread_info(task)->syscall;
+}
+
+static inline void syscall_rollback(struct task_struct *task,
+				    struct pt_regs *regs)
+{
+	regs->ARM_r0 = regs->ARM_ORIG_r0;
+}
+
+static inline long syscall_get_error(struct task_struct *task,
+				     struct pt_regs *regs)
+{
+	unsigned long error = regs->ARM_r0;
+	return IS_ERR_VALUE(error) ? error : 0;
+}
+
+static inline long syscall_get_return_value(struct task_struct *task,
+					    struct pt_regs *regs)
+{
+	return regs->ARM_r0;
+}
+
+static inline void syscall_set_return_value(struct task_struct *task,
+					    struct pt_regs *regs,
+					    int error, long val)
+{
+	regs->ARM_r0 = (long) error ? error : val;
+}
+
+#define SYSCALL_MAX_ARGS 7
+
+static inline void syscall_get_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 unsigned int i, unsigned int n,
+					 unsigned long *args)
+{
+	if (i + n > SYSCALL_MAX_ARGS) {
+		unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i;
+		unsigned int n_bad = n + i - SYSCALL_MAX_ARGS;
+		pr_warning("%s called with max args %d, handling only %d\n",
+			   __func__, i + n, SYSCALL_MAX_ARGS);
+		memset(args_bad, 0, n_bad * sizeof(args[0]));
+		n = SYSCALL_MAX_ARGS - i;
+	}
+
+	if (i == 0) {
+		args[0] = regs->ARM_ORIG_r0;
+		args++;
+		i++;
+		n--;
+	}
+
+	memcpy(args, &regs->ARM_r0 + i, n * sizeof(args[0]));
+}
+
+static inline void syscall_set_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 unsigned int i, unsigned int n,
+					 const unsigned long *args)
+{
+	if (i + n > SYSCALL_MAX_ARGS) {
+		pr_warning("%s called with max args %d, handling only %d\n",
+			   __func__, i + n, SYSCALL_MAX_ARGS);
+		n = SYSCALL_MAX_ARGS - i;
+	}
+
+	if (i == 0) {
+		regs->ARM_ORIG_r0 = args[0];
+		args++;
+		i++;
+		n--;
+	}
+
+	memcpy(&regs->ARM_r0 + i, args, n * sizeof(args[0]));
+}
+
+#endif /* _ASM_ARM_SYSCALL_H */
Signature · 1 line
1.7.0.4
author
#10 lore raw

PATCH v2 2/3 ARM: add TRACEHOOK support

In reply to Wade Farnsworth

Add calls to tracehook_report_syscall_{entry,exit} and tracehook_signal_handler

Signed-off-by Steven Walter <[email protected]>
Signed-off-by Wade Farnsworth <[email protected]>
---
 arch/arm/Kconfig              |    1 +
 arch/arm/include/asm/ptrace.h |    5 +++++
 arch/arm/kernel/ptrace.c      |   21 ++++++---------------
 arch/arm/kernel/signal.c      |    2 ++
 4 files changed, 14 insertions(+), 15 deletions(-)
arch/arm/Kconfig +1 -0
index a48aecc..0faad0c 100644
@@ -10,6 +10,7 @@ config ARM
 	select GENERIC_ATOMIC64 if (CPU_V6 || !CPU_32v6K || !AEABI)
 	select HAVE_OPROFILE if (HAVE_PERF_EVENTS)
 	select HAVE_ARCH_KGDB
+	select HAVE_ARCH_TRACEHOOK
 	select HAVE_KPROBES if !XIP_KERNEL
 	select HAVE_KRETPROBES if (HAVE_KPROBES)
 	select HAVE_FUNCTION_TRACER if (!XIP_KERNEL)
arch/arm/include/asm/ptrace.h +5 -0
index 451808b..355ece5 100644
@@ -249,6 +249,11 @@ static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
 	return regs->ARM_sp;
 }
 
+static inline unsigned long user_stack_pointer(struct pt_regs *regs)
+{
+	return regs->ARM_sp;
+}
+
 #endif /* __KERNEL__ */
 
 #endif /* __ASSEMBLY__ */
arch/arm/kernel/ptrace.c +6 -15
index ede6443..46f4b41 100644
@@ -24,6 +24,7 @@
 #include <linux/hw_breakpoint.h>
 #include <linux/regset.h>
 #include <linux/audit.h>
+#include <linux/tracehook.h>
 
 #include <asm/pgtable.h>
 #include <asm/system.h>

@@ -930,24 +931,14 @@ asmlinkage int syscall_trace(int why, struct pt_regs *regs, int scno)
 
 	if (!test_thread_flag(TIF_SYSCALL_TRACE))
 		return scno;
-	if (!(current->ptrace & PT_PTRACED))
-		return scno;
 
 	current_thread_info()->syscall = scno;
 
-	/* the 0x80 provides a way for the tracing parent to distinguish
-	   between a syscall stop and SIGTRAP delivery */
-	ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
-				 ? 0x80 : 0));
-	/*
-	 * this isn't the same as continuing with a signal, but it will do
-	 * for normal use.  strace only continues with a signal if the
-	 * stopping signal is not SIGTRAP.  -brl
-	 */
-	if (current->exit_code) {
-		send_sig(current->exit_code, current, 1);
-		current->exit_code = 0;
-	}
+	if (why)
+		tracehook_report_syscall_exit(regs, 0);
+	else if (tracehook_report_syscall_entry(regs))
+		current_thread_info()->syscall = -1;
+
 	regs->ARM_ip = ip;
 
 	return current_thread_info()->syscall;
arch/arm/kernel/signal.c +2 -0
index 9e617bd..6f084c1 100644
@@ -644,6 +644,8 @@ handle_signal(unsigned long sig, struct k_sigaction *ka,
 	recalc_sigpending();
 	spin_unlock_irq(&tsk->sighand->siglock);
 
+	tracehook_signal_handler(sig, info, ka, regs, 0);
+
 	return 0;
 }
Signature · 1 line
1.7.0.4
author
#11 lore raw

PATCH v2 3/3 ARM: support syscall tracing

In reply to Wade Farnsworth

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 <[email protected]>
Signed-off-by Wade Farnsworth <[email protected]>
---
 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     |   16 ++++++++++++++--
 arch/arm/kernel/ptrace.c           |   23 ++++++++++++++++++-----
 6 files changed, 47 insertions(+), 7 deletions(-)
arch/arm/Kconfig +1 -0
index 0faad0c..b1d9396 100644
@@ -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)
arch/arm/include/asm/syscall.h +4 -0
index c334a23..47486a4 100644
@@ -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,
arch/arm/include/asm/thread_info.h +2 -0
index d4c24d4..f2ff2de 100644
@@ -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)
arch/arm/include/asm/unistd.h +8 -0
index 512cd14..d27d7d7 100644
@@ -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)
arch/arm/kernel/entry-common.S +14 -2
index 9fd0ba9..01686b2 100644
@@ -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 +103,13 @@ 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 not larger than __NR_syscalls,
+ * which is the value the rest of the system sees */
+.ifne NR_syscalls - __NR_syscalls
+.error "__NR_syscalls is less than the size of the syscall table"
+.endif
+
 #undef CALL
 #define CALL(x) .long x
 

@@ -446,7 +458,7 @@ 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
arch/arm/kernel/ptrace.c +18 -5
index 46f4b41..dbbf4ce 100644
@@ -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;
Signature · 1 line
1.7.0.4
#12 lore raw

v2 cover ARM support for syscall tracing

In reply to Wade Farnsworth

Hi Wade,

Quoted 15 lines · Wade Farnsworth

This is a rework of Steven Walter's syscall tracing patches first posted here:

http://lists.infradead.org/pipermail/linux-arm-kernel/2011-November/074454.html

I've rebased the patches against the current mainline master branch, as well as implemented several changes based on feedback from Will Deacon and Russel King.

v2: - Tested on EABI and OABI.
- Removed an instance of the ?: operator in syscall_set_return_value()
- Moved #define of NR_syscalls to syscall.h
- Changed the test of NR_syscalls vs __NR_syscalls in entry-common.S to .ifne

Quoted 4 lines

Wade Farnsworth (3):
ARM: add support for the generic syscall.h interface
ARM: add TRACEHOOK support
ARM: support syscall tracing

I'm pretty happy with these three patches now, so feel free to add:

Reviewed-by Will Deacon <[email protected]>

Once Russell is ok with them you can put them in the patch system.

Cheers,

Will

author
#13 lore raw

v3 cover ARM support for syscall tracing

In reply to Wade Farnsworth

This is a rework of Steven Walter's syscall tracing patches first posted here:

http://lists.infradead.org/pipermail/linux-arm-kernel/2011-November/074454.html

I've rebased the patches against the current mainline master branch, as well as implemented several changes based on feedback from Will Deacon and Russell King.

v2: - Tested on EABI and OABI.
- Removed an instance of the ?: operator in syscall_set_return_value()
- Moved #define of NR_syscalls to syscall.h
- Changed the test of NR_syscalls vs __NR_syscalls in entry-common.S to .ifne
v3: - Added Will Deacon's Reviewed-by line. Code is identical to v2.

Wade Farnsworth (3):
ARM: add support for the generic syscall.h interface
ARM: add TRACEHOOK support
ARM: support syscall tracing

 arch/arm/Kconfig                   |    2 +
 arch/arm/include/asm/ptrace.h      |    5 ++
 arch/arm/include/asm/syscall.h     |   97 ++++++++++++++++++++++++++++++++++++
 arch/arm/include/asm/thread_info.h |    2 +
 arch/arm/include/asm/unistd.h      |    8 +++
 arch/arm/kernel/entry-common.S     |   16 +++++-
 arch/arm/kernel/ptrace.c           |   34 +++++++------
 arch/arm/kernel/signal.c           |    2 +
 8 files changed, 149 insertions(+), 17 deletions(-)
 create mode 100644 arch/arm/include/asm/syscall.h
author
#14 lore raw

PATCH v3 1/3 ARM: add support for the generic syscall.h interface

Supplying the asm-generic/syscall.h interface is a pre-requisite for HAVE_ARCH_TRACEHOOK

Signed-off-by Steven Walter <[email protected]>
Signed-off-by Wade Farnsworth <[email protected]>
Reviewed-by Will Deacon <[email protected]>
---
 arch/arm/include/asm/syscall.h |   93 ++++++++++++++++++++++++++++++++++++++++
 1 files changed, 93 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm/include/asm/syscall.h
arch/arm/include/asm/syscall.h new file +93 -0
new file mode 100644
index 0000000..c334a23
@@ -0,0 +1,93 @@
+/*
+ * Access to user system call parameters and results
+ *
+ * See asm-generic/syscall.h for descriptions of what we must do here.
+ */
+
+#ifndef _ASM_ARM_SYSCALL_H
+#define _ASM_ARM_SYSCALL_H
+
+#include <linux/err.h>
+
+extern const unsigned long sys_call_table[];
+
+static inline int syscall_get_nr(struct task_struct *task,
+				 struct pt_regs *regs)
+{
+	return task_thread_info(task)->syscall;
+}
+
+static inline void syscall_rollback(struct task_struct *task,
+				    struct pt_regs *regs)
+{
+	regs->ARM_r0 = regs->ARM_ORIG_r0;
+}
+
+static inline long syscall_get_error(struct task_struct *task,
+				     struct pt_regs *regs)
+{
+	unsigned long error = regs->ARM_r0;
+	return IS_ERR_VALUE(error) ? error : 0;
+}
+
+static inline long syscall_get_return_value(struct task_struct *task,
+					    struct pt_regs *regs)
+{
+	return regs->ARM_r0;
+}
+
+static inline void syscall_set_return_value(struct task_struct *task,
+					    struct pt_regs *regs,
+					    int error, long val)
+{
+	regs->ARM_r0 = (long) error ? error : val;
+}
+
+#define SYSCALL_MAX_ARGS 7
+
+static inline void syscall_get_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 unsigned int i, unsigned int n,
+					 unsigned long *args)
+{
+	if (i + n > SYSCALL_MAX_ARGS) {
+		unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i;
+		unsigned int n_bad = n + i - SYSCALL_MAX_ARGS;
+		pr_warning("%s called with max args %d, handling only %d\n",
+			   __func__, i + n, SYSCALL_MAX_ARGS);
+		memset(args_bad, 0, n_bad * sizeof(args[0]));
+		n = SYSCALL_MAX_ARGS - i;
+	}
+
+	if (i == 0) {
+		args[0] = regs->ARM_ORIG_r0;
+		args++;
+		i++;
+		n--;
+	}
+
+	memcpy(args, &regs->ARM_r0 + i, n * sizeof(args[0]));
+}
+
+static inline void syscall_set_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 unsigned int i, unsigned int n,
+					 const unsigned long *args)
+{
+	if (i + n > SYSCALL_MAX_ARGS) {
+		pr_warning("%s called with max args %d, handling only %d\n",
+			   __func__, i + n, SYSCALL_MAX_ARGS);
+		n = SYSCALL_MAX_ARGS - i;
+	}
+
+	if (i == 0) {
+		regs->ARM_ORIG_r0 = args[0];
+		args++;
+		i++;
+		n--;
+	}
+
+	memcpy(&regs->ARM_r0 + i, args, n * sizeof(args[0]));
+}
+
+#endif /* _ASM_ARM_SYSCALL_H */
Signature · 1 line
1.7.0.4
author
#15 lore raw

PATCH v3 2/3 ARM: add TRACEHOOK support

In reply to Wade Farnsworth

Add calls to tracehook_report_syscall_{entry,exit} and tracehook_signal_handler

Signed-off-by Steven Walter <[email protected]>
Signed-off-by Wade Farnsworth <[email protected]>
Reviewed-by Will Deacon <[email protected]>
---
 arch/arm/Kconfig              |    1 +
 arch/arm/include/asm/ptrace.h |    5 +++++
 arch/arm/kernel/ptrace.c      |   21 ++++++---------------
 arch/arm/kernel/signal.c      |    2 ++
 4 files changed, 14 insertions(+), 15 deletions(-)
arch/arm/Kconfig +1 -0
index a48aecc..0faad0c 100644
@@ -10,6 +10,7 @@ config ARM
 	select GENERIC_ATOMIC64 if (CPU_V6 || !CPU_32v6K || !AEABI)
 	select HAVE_OPROFILE if (HAVE_PERF_EVENTS)
 	select HAVE_ARCH_KGDB
+	select HAVE_ARCH_TRACEHOOK
 	select HAVE_KPROBES if !XIP_KERNEL
 	select HAVE_KRETPROBES if (HAVE_KPROBES)
 	select HAVE_FUNCTION_TRACER if (!XIP_KERNEL)
arch/arm/include/asm/ptrace.h +5 -0
index 451808b..355ece5 100644
@@ -249,6 +249,11 @@ static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
 	return regs->ARM_sp;
 }
 
+static inline unsigned long user_stack_pointer(struct pt_regs *regs)
+{
+	return regs->ARM_sp;
+}
+
 #endif /* __KERNEL__ */
 
 #endif /* __ASSEMBLY__ */
arch/arm/kernel/ptrace.c +6 -15
index ede6443..46f4b41 100644
@@ -24,6 +24,7 @@
 #include <linux/hw_breakpoint.h>
 #include <linux/regset.h>
 #include <linux/audit.h>
+#include <linux/tracehook.h>
 
 #include <asm/pgtable.h>
 #include <asm/system.h>

@@ -930,24 +931,14 @@ asmlinkage int syscall_trace(int why, struct pt_regs *regs, int scno)
 
 	if (!test_thread_flag(TIF_SYSCALL_TRACE))
 		return scno;
-	if (!(current->ptrace & PT_PTRACED))
-		return scno;
 
 	current_thread_info()->syscall = scno;
 
-	/* the 0x80 provides a way for the tracing parent to distinguish
-	   between a syscall stop and SIGTRAP delivery */
-	ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
-				 ? 0x80 : 0));
-	/*
-	 * this isn't the same as continuing with a signal, but it will do
-	 * for normal use.  strace only continues with a signal if the
-	 * stopping signal is not SIGTRAP.  -brl
-	 */
-	if (current->exit_code) {
-		send_sig(current->exit_code, current, 1);
-		current->exit_code = 0;
-	}
+	if (why)
+		tracehook_report_syscall_exit(regs, 0);
+	else if (tracehook_report_syscall_entry(regs))
+		current_thread_info()->syscall = -1;
+
 	regs->ARM_ip = ip;
 
 	return current_thread_info()->syscall;
arch/arm/kernel/signal.c +2 -0
index 9e617bd..6f084c1 100644
@@ -644,6 +644,8 @@ handle_signal(unsigned long sig, struct k_sigaction *ka,
 	recalc_sigpending();
 	spin_unlock_irq(&tsk->sighand->siglock);
 
+	tracehook_signal_handler(sig, info, ka, regs, 0);
+
 	return 0;
 }
Signature · 1 line
1.7.0.4
author
#16 lore raw

PATCH v3 3/3 ARM: support syscall tracing

In reply to Wade Farnsworth

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 <[email protected]>
Signed-off-by Wade Farnsworth <[email protected]>
Reviewed-by Will Deacon <[email protected]>
---
 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     |   16 ++++++++++++++--
 arch/arm/kernel/ptrace.c           |   23 ++++++++++++++++++-----
 6 files changed, 47 insertions(+), 7 deletions(-)
arch/arm/Kconfig +1 -0
index 0faad0c..b1d9396 100644
@@ -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)
arch/arm/include/asm/syscall.h +4 -0
index c334a23..47486a4 100644
@@ -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,
arch/arm/include/asm/thread_info.h +2 -0
index d4c24d4..f2ff2de 100644
@@ -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)
arch/arm/include/asm/unistd.h +8 -0
index 512cd14..d27d7d7 100644
@@ -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)
arch/arm/kernel/entry-common.S +14 -2
index 9fd0ba9..01686b2 100644
@@ -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 +103,13 @@ 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 not larger than __NR_syscalls,
+ * which is the value the rest of the system sees */
+.ifne NR_syscalls - __NR_syscalls
+.error "__NR_syscalls is less than the size of the syscall table"
+.endif
+
 #undef CALL
 #define CALL(x) .long x
 

@@ -446,7 +458,7 @@ 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
arch/arm/kernel/ptrace.c +18 -5
index 46f4b41..dbbf4ce 100644
@@ -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;
Signature · 1 line
1.7.0.4
author
#17 lore raw

v4 cover ARM support for syscall tracing

In reply to Wade Farnsworth

This is a rework of Steven Walter's syscall tracing patches first posted here:

http://lists.infradead.org/pipermail/linux-arm-kernel/2011-November/074454.html

I've rebased the patches against the current mainline master branch, as well as implemented several changes based on feedback from Will Deacon and Russel King.

v2: - Tested on EABI and OABI.
- Removed an instance of the ?: operator in syscall_set_return_value()
- Moved #define of NR_syscalls to syscall.h
- Changed the test of NR_syscalls vs __NR_syscalls in entry-common.S to .ifne
v3: - Added Will Deacon's Reviewed-by line. Code is identical to v2.
v4: - Updated comment and error string for the NR_syscalls test to
reflect that it's now testing for inequality.

Russell, now that this has been reviewed by Will and tested with both ABIs, is this okay to submit to your patch tracker?

Wade Farnsworth (3):
ARM: add support for the generic syscall.h interface
ARM: add TRACEHOOK support
ARM: support syscall tracing

 arch/arm/Kconfig                   |    2 +
 arch/arm/include/asm/ptrace.h      |    5 ++
 arch/arm/include/asm/syscall.h     |   97 ++++++++++++++++++++++++++++++++++++
 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           |   34 +++++++------
 arch/arm/kernel/signal.c           |    2 +
 8 files changed, 151 insertions(+), 17 deletions(-)
 create mode 100644 arch/arm/include/asm/syscall.h
author
#18 lore raw

PATCH v4 1/3 ARM: add support for the generic syscall.h interface

Supplying the asm-generic/syscall.h interface is a pre-requisite for HAVE_ARCH_TRACEHOOK

Signed-off-by Steven Walter <[email protected]>
Signed-off-by Wade Farnsworth <[email protected]>
Reviewed-by Will Deacon <[email protected]>
---
 arch/arm/include/asm/syscall.h |   93 ++++++++++++++++++++++++++++++++++++++++
 1 files changed, 93 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm/include/asm/syscall.h
arch/arm/include/asm/syscall.h new file +93 -0
new file mode 100644
index 0000000..c334a23
@@ -0,0 +1,93 @@
+/*
+ * Access to user system call parameters and results
+ *
+ * See asm-generic/syscall.h for descriptions of what we must do here.
+ */
+
+#ifndef _ASM_ARM_SYSCALL_H
+#define _ASM_ARM_SYSCALL_H
+
+#include <linux/err.h>
+
+extern const unsigned long sys_call_table[];
+
+static inline int syscall_get_nr(struct task_struct *task,
+				 struct pt_regs *regs)
+{
+	return task_thread_info(task)->syscall;
+}
+
+static inline void syscall_rollback(struct task_struct *task,
+				    struct pt_regs *regs)
+{
+	regs->ARM_r0 = regs->ARM_ORIG_r0;
+}
+
+static inline long syscall_get_error(struct task_struct *task,
+				     struct pt_regs *regs)
+{
+	unsigned long error = regs->ARM_r0;
+	return IS_ERR_VALUE(error) ? error : 0;
+}
+
+static inline long syscall_get_return_value(struct task_struct *task,
+					    struct pt_regs *regs)
+{
+	return regs->ARM_r0;
+}
+
+static inline void syscall_set_return_value(struct task_struct *task,
+					    struct pt_regs *regs,
+					    int error, long val)
+{
+	regs->ARM_r0 = (long) error ? error : val;
+}
+
+#define SYSCALL_MAX_ARGS 7
+
+static inline void syscall_get_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 unsigned int i, unsigned int n,
+					 unsigned long *args)
+{
+	if (i + n > SYSCALL_MAX_ARGS) {
+		unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i;
+		unsigned int n_bad = n + i - SYSCALL_MAX_ARGS;
+		pr_warning("%s called with max args %d, handling only %d\n",
+			   __func__, i + n, SYSCALL_MAX_ARGS);
+		memset(args_bad, 0, n_bad * sizeof(args[0]));
+		n = SYSCALL_MAX_ARGS - i;
+	}
+
+	if (i == 0) {
+		args[0] = regs->ARM_ORIG_r0;
+		args++;
+		i++;
+		n--;
+	}
+
+	memcpy(args, &regs->ARM_r0 + i, n * sizeof(args[0]));
+}
+
+static inline void syscall_set_arguments(struct task_struct *task,
+					 struct pt_regs *regs,
+					 unsigned int i, unsigned int n,
+					 const unsigned long *args)
+{
+	if (i + n > SYSCALL_MAX_ARGS) {
+		pr_warning("%s called with max args %d, handling only %d\n",
+			   __func__, i + n, SYSCALL_MAX_ARGS);
+		n = SYSCALL_MAX_ARGS - i;
+	}
+
+	if (i == 0) {
+		regs->ARM_ORIG_r0 = args[0];
+		args++;
+		i++;
+		n--;
+	}
+
+	memcpy(&regs->ARM_r0 + i, args, n * sizeof(args[0]));
+}
+
+#endif /* _ASM_ARM_SYSCALL_H */
Signature · 1 line
1.7.0.4
author
#19 lore raw

PATCH v4 2/3 ARM: add TRACEHOOK support

In reply to Wade Farnsworth

Add calls to tracehook_report_syscall_{entry,exit} and tracehook_signal_handler

Signed-off-by Steven Walter <[email protected]>
Signed-off-by Wade Farnsworth <[email protected]>
Reviewed-by Will Deacon <[email protected]>
---
 arch/arm/Kconfig              |    1 +
 arch/arm/include/asm/ptrace.h |    5 +++++
 arch/arm/kernel/ptrace.c      |   21 ++++++---------------
 arch/arm/kernel/signal.c      |    2 ++
 4 files changed, 14 insertions(+), 15 deletions(-)
arch/arm/Kconfig +1 -0
index dfb0312..c87e23f 100644
@@ -10,6 +10,7 @@ config ARM
 	select GENERIC_ATOMIC64 if (CPU_V6 || !CPU_32v6K || !AEABI)
 	select HAVE_OPROFILE if (HAVE_PERF_EVENTS)
 	select HAVE_ARCH_KGDB
+	select HAVE_ARCH_TRACEHOOK
 	select HAVE_KPROBES if !XIP_KERNEL
 	select HAVE_KRETPROBES if (HAVE_KPROBES)
 	select HAVE_FUNCTION_TRACER if (!XIP_KERNEL)
arch/arm/include/asm/ptrace.h +5 -0
index 451808b..355ece5 100644
@@ -249,6 +249,11 @@ static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
 	return regs->ARM_sp;
 }
 
+static inline unsigned long user_stack_pointer(struct pt_regs *regs)
+{
+	return regs->ARM_sp;
+}
+
 #endif /* __KERNEL__ */
 
 #endif /* __ASSEMBLY__ */
arch/arm/kernel/ptrace.c +6 -15
index ede6443..46f4b41 100644
@@ -24,6 +24,7 @@
 #include <linux/hw_breakpoint.h>
 #include <linux/regset.h>
 #include <linux/audit.h>
+#include <linux/tracehook.h>
 
 #include <asm/pgtable.h>
 #include <asm/system.h>

@@ -930,24 +931,14 @@ asmlinkage int syscall_trace(int why, struct pt_regs *regs, int scno)
 
 	if (!test_thread_flag(TIF_SYSCALL_TRACE))
 		return scno;
-	if (!(current->ptrace & PT_PTRACED))
-		return scno;
 
 	current_thread_info()->syscall = scno;
 
-	/* the 0x80 provides a way for the tracing parent to distinguish
-	   between a syscall stop and SIGTRAP delivery */
-	ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
-				 ? 0x80 : 0));
-	/*
-	 * this isn't the same as continuing with a signal, but it will do
-	 * for normal use.  strace only continues with a signal if the
-	 * stopping signal is not SIGTRAP.  -brl
-	 */
-	if (current->exit_code) {
-		send_sig(current->exit_code, current, 1);
-		current->exit_code = 0;
-	}
+	if (why)
+		tracehook_report_syscall_exit(regs, 0);
+	else if (tracehook_report_syscall_entry(regs))
+		current_thread_info()->syscall = -1;
+
 	regs->ARM_ip = ip;
 
 	return current_thread_info()->syscall;
arch/arm/kernel/signal.c +2 -0
index 9e617bd..6f084c1 100644
@@ -644,6 +644,8 @@ handle_signal(unsigned long sig, struct k_sigaction *ka,
 	recalc_sigpending();
 	spin_unlock_irq(&tsk->sighand->siglock);
 
+	tracehook_signal_handler(sig, info, ka, regs, 0);
+
 	return 0;
 }
Signature · 1 line
1.7.0.4
author
#20 lore raw

PATCH v4 3/3 ARM: support syscall tracing

In reply to Wade Farnsworth

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 <[email protected]>
Signed-off-by Wade Farnsworth <[email protected]>
Reviewed-by Will Deacon <[email protected]>
---
 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(-)
arch/arm/Kconfig +1 -0
index c87e23f..5603715 100644
@@ -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)
arch/arm/include/asm/syscall.h +4 -0
index c334a23..47486a4 100644
@@ -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,
arch/arm/include/asm/thread_info.h +2 -0
index d4c24d4..f2ff2de 100644
@@ -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)
arch/arm/include/asm/unistd.h +8 -0
index 512cd14..d27d7d7 100644
@@ -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)
arch/arm/kernel/entry-common.S +16 -2
index 9fd0ba9..3df0ca3 100644
@@ -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
arch/arm/kernel/ptrace.c +18 -5
index 46f4b41..dbbf4ce 100644
@@ -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;
Signature · 1 line
1.7.0.4
#21 lore raw

v4 cover ARM support for syscall tracing

In reply to Wade Farnsworth

Hi Wade,

Quoted 2 lines · Wade Farnsworth

Russell, now that this has been reviewed by Will and tested with both ABIs, is this okay to submit to your patch tracker?

I'd recommend putting this into the patch system once -rc1 has landed. Any conflicts after that are fairly unlikely and Russell can decide what to do with the patches then.

Cheers,

Will