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Subject[PATCH 3/4] tile: Add support for TIF_SYSCALL_TRACEPOINT
Date
This patch adds support for the TIF_SYSCALL_TRACEPOINT on the tile
architecture. Basically, it calls the appropriate tracepoints on syscall
entry and exit.

Signed-off-by: Simon Marchi <simon.marchi@polymtl.ca>
---
arch/tile/include/asm/thread_info.h | 8 ++++++++
arch/tile/kernel/intvec_64.S | 14 ++++++++++----
arch/tile/kernel/ptrace.c | 17 ++++++++++++++---
3 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/arch/tile/include/asm/thread_info.h b/arch/tile/include/asm/thread_info.h
index e9c670d..c96331e 100644
--- a/arch/tile/include/asm/thread_info.h
+++ b/arch/tile/include/asm/thread_info.h
@@ -124,6 +124,7 @@ extern void _cpu_idle(void);
#define TIF_SECCOMP 6 /* secure computing */
#define TIF_MEMDIE 7 /* OOM killer at work */
#define TIF_NOTIFY_RESUME 8 /* callback before returning to user */
+#define TIF_SYSCALL_TRACEPOINT 9 /* syscall tracepoint instrumentation */

#define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
@@ -134,12 +135,19 @@ extern void _cpu_idle(void);
#define _TIF_SECCOMP (1<<TIF_SECCOMP)
#define _TIF_MEMDIE (1<<TIF_MEMDIE)
#define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
+#define _TIF_SYSCALL_TRACEPOINT (1<<TIF_SYSCALL_TRACEPOINT)

/* Work to do on any return to user space. */
#define _TIF_ALLWORK_MASK \
(_TIF_SIGPENDING|_TIF_NEED_RESCHED|_TIF_SINGLESTEP|\
_TIF_ASYNC_TLB|_TIF_NOTIFY_RESUME)

+/* Work to do at syscall entry. */
+#define _TIF_SYSCALL_ENTRY_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT)
+
+/* Work to do at syscall exit. */
+#define _TIF_SYSCALL_EXIT_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT)
+
/*
* Thread-synchronous status.
*
diff --git a/arch/tile/kernel/intvec_64.S b/arch/tile/kernel/intvec_64.S
index fd78cd4..505e6d4 100644
--- a/arch/tile/kernel/intvec_64.S
+++ b/arch/tile/kernel/intvec_64.S
@@ -1000,8 +1000,11 @@ handle_syscall:

/* Trace syscalls, if requested. */
addi r31, r31, THREAD_INFO_FLAGS_OFFSET
- ld r30, r31
- andi r30, r30, _TIF_SYSCALL_TRACE
+ {
+ ld r30, r31
+ moveli r32, _TIF_SYSCALL_ENTRY_WORK
+ }
+ and r30, r30, r32
{
addi r30, r31, THREAD_INFO_STATUS_OFFSET - THREAD_INFO_FLAGS_OFFSET
beqzt r30, .Lrestore_syscall_regs
@@ -1070,8 +1073,11 @@ handle_syscall:
FEEDBACK_REENTER(handle_syscall)

/* Do syscall trace again, if requested. */
- ld r30, r31
- andi r0, r30, _TIF_SYSCALL_TRACE
+ {
+ ld r30, r31
+ moveli r32, _TIF_SYSCALL_EXIT_WORK
+ }
+ and r0, r30, r32
{
andi r0, r30, _TIF_SINGLESTEP
beqzt r0, 1f
diff --git a/arch/tile/kernel/ptrace.c b/arch/tile/kernel/ptrace.c
index 0ab8b76..363b2dd 100644
--- a/arch/tile/kernel/ptrace.c
+++ b/arch/tile/kernel/ptrace.c
@@ -25,6 +25,9 @@
#include <asm/traps.h>
#include <arch/chip.h>

+#define CREATE_TRACE_POINTS
+#include <trace/events/syscalls.h>
+
void user_enable_single_step(struct task_struct *child)
{
set_tsk_thread_flag(child, TIF_SINGLESTEP);
@@ -249,16 +252,24 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,

int do_syscall_trace_enter(struct pt_regs *regs)
{
- if (tracehook_report_syscall_entry(regs)) {
- regs->regs[TREG_SYSCALL_NR] = -1;
+ if (test_thread_flag(TIF_SYSCALL_TRACE)) {
+ if (tracehook_report_syscall_entry(regs))
+ regs->regs[TREG_SYSCALL_NR] = -1;
}

+ if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
+ trace_sys_enter(regs, regs->regs[TREG_SYSCALL_NR]);
+
return regs->regs[TREG_SYSCALL_NR];
}

void do_syscall_trace_exit(struct pt_regs *regs)
{
- tracehook_report_syscall_exit(regs, 0);
+ if (test_thread_flag(TIF_SYSCALL_TRACE))
+ tracehook_report_syscall_exit(regs, 0);
+
+ if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
+ trace_sys_exit(regs, regs->regs[TREG_SYSCALL_NR]);
}

void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code)
--
1.7.1


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