[RFC PATCH v2 1/6] powerpc: Syscall hooks for context tracking subsystem

Li Zhong
2013-03-29T10:01:05Z

This is the syscall slow path hooks for context tracking subsystem,
corresponding to
[PATCH] x86: Syscall hooks for userspace RCU extended QS
commit bf5a3c13b939813d28ce26c01425054c740d6731

TIF_MEMDIE is moved to the second 16-bits (with value 17), as it seems there
is no asm code using it. TIF_NOHZ is added to _TIF_SYCALL_T_OR_A, so it is
better for it to be in the same 16 bits with others in the group, so in the
asm code, andi. with this group could work.

Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
---
arch/powerpc/include/asm/thread_info.h | 7 +++++--
arch/powerpc/kernel/ptrace.c | 5 +++++
2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h
index 406b7b9..414a261 100644
--- a/arch/powerpc/include/asm/thread_info.h
+++ b/arch/powerpc/include/asm/thread_info.h
@@ -97,7 +97,7 @@ static inline struct thread_info *current_thread_info(void)
#define TIF_PERFMON_CTXSW 6 /* perfmon needs ctxsw calls */
#define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */
#define TIF_SINGLESTEP 8 /* singlestepping active */
-#define TIF_MEMDIE 9 /* is terminating due to OOM killer */
+#define TIF_NOHZ 9 /* in adaptive nohz mode */
#define TIF_SECCOMP 10 /* secure computing */
#define TIF_RESTOREALL 11 /* Restore all regs (implies NOERROR) */
#define TIF_NOERROR 12 /* Force successful syscall return */
@@ -106,6 +106,7 @@ static inline struct thread_info *current_thread_info(void)
#define TIF_SYSCALL_TRACEPOINT 15 /* syscall tracepoint instrumentation */
#define TIF_EMULATE_STACK_STORE 16 /* Is an instruction emulation
for stack store? */
+#define TIF_MEMDIE 17 /* is terminating due to OOM killer */

/* as above, but as bit values */
#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
@@ -124,8 +125,10 @@ static inline struct thread_info *current_thread_info(void)
#define _TIF_UPROBE (1<<TIF_UPROBE)
#define _TIF_SYSCALL_TRACEPOINT (1<<TIF_SYSCALL_TRACEPOINT)
#define _TIF_EMULATE_STACK_STORE (1<<TIF_EMULATE_STACK_STORE)
+#define _TIF_NOHZ (1<<TIF_NOHZ)
#define _TIF_SYSCALL_T_OR_A (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
- _TIF_SECCOMP | _TIF_SYSCALL_TRACEPOINT)
+ _TIF_SECCOMP | _TIF_SYSCALL_TRACEPOINT | \
+ _TIF_NOHZ)

#define _TIF_USER_WORK_MASK (_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
_TIF_NOTIFY_RESUME | _TIF_UPROBE)
diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index 245c1b6..0b7aad0 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
@@ -32,6 +32,7 @@
#include <trace/syscall.h>
#include <linux/hw_breakpoint.h>
#include <linux/perf_event.h>
+#include <linux/context_tracking.h>

#include <asm/uaccess.h>
#include <asm/page.h>
@@ -1778,6 +1779,8 @@ long do_syscall_trace_enter(struct pt_regs *regs)
{
long ret = 0;

+ user_exit();
+
secure_computing_strict(regs->gpr[0]);

if (test_thread_flag(TIF_SYSCALL_TRACE) &&
@@ -1822,4 +1825,6 @@ void do_syscall_trace_leave(struct pt_regs *regs)
step = test_thread_flag(TIF_SINGLESTEP);
if (step || test_thread_flag(TIF_SYSCALL_TRACE))
tracehook_report_syscall_exit(regs, step);
+
+ user_enter();
}
--
1.7.9.5