Add PTRACE_SYSEMU and PTRACE_SYSEMU_SINGLESTEP support on arm64.
We don't need any special handling for PTRACE_SYSEMU_SINGLESTEP.
It's quite difficult to generalize handling PTRACE_SYSEMU cross
architectures and avoid calls to tracehook_report_syscall_entry twice.
Different architecture have different mechanism to indicate NO_SYSCALL
and trying to generalise adds more code for no gain.
Cc: Catalin Marinas <catalin.mari...@arm.com>
Cc: Will Deacon <will.dea...@arm.com>
Signed-off-by: Sudeep Holla <sudeep.ho...@arm.com>
---
arch/arm64/include/asm/thread_info.h | 5 ++++-
arch/arm64/kernel/ptrace.c | 6 +++++-
2 files changed, 9 insertions(+), 2 deletions(-)
Hi Will,
While I agree with your idea of consolidation of PTRACE_SYSEMU handling
to core, it's quite a lot of change to do that, though it may be simple
and confusing with indirection from arch code to core.
Regards,
Sudeep
diff --git a/arch/arm64/include/asm/thread_info.h
b/arch/arm64/include/asm/thread_info.h
index eb3ef73e07cf..c285d1ce7186 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -75,6 +75,7 @@ void arch_release_task_struct(struct task_struct *tsk);
* TIF_SYSCALL_TRACE - syscall trace active
* TIF_SYSCALL_TRACEPOINT - syscall tracepoint for ftrace
* TIF_SYSCALL_AUDIT - syscall auditing
+ * TIF_SYSCALL_EMU - syscall emulation active
* TIF_SECOMP - syscall secure computing
* TIF_SIGPENDING - signal pending
* TIF_NEED_RESCHED - rescheduling necessary
@@ -91,6 +92,7 @@ void arch_release_task_struct(struct task_struct *tsk);
#define TIF_SYSCALL_AUDIT 9
#define TIF_SYSCALL_TRACEPOINT 10
#define TIF_SECCOMP 11
+#define TIF_SYSCALL_EMU 12
#define TIF_MEMDIE 18 /* is terminating due to OOM killer */
#define TIF_FREEZE 19
#define TIF_RESTORE_SIGMASK 20
@@ -109,6 +111,7 @@ void arch_release_task_struct(struct task_struct *tsk);
#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
#define _TIF_SECCOMP (1 << TIF_SECCOMP)
+#define _TIF_SYSCALL_EMU (1 << TIF_SYSCALL_EMU)
#define _TIF_UPROBE (1 << TIF_UPROBE)
#define _TIF_FSCHECK (1 << TIF_FSCHECK)
#define _TIF_32BIT (1 << TIF_32BIT)
@@ -120,7 +123,7 @@ void arch_release_task_struct(struct task_struct *tsk);
#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
_TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP | \
- _TIF_NOHZ)
+ _TIF_NOHZ | _TIF_SYSCALL_EMU)
#define INIT_THREAD_INFO(tsk) \
{ \
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index b82e0a9b3da3..9353355cb91a 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -1819,8 +1819,12 @@ static void tracehook_report_syscall(struct pt_regs
*regs,
int syscall_trace_enter(struct pt_regs *regs)
{
- if (test_thread_flag(TIF_SYSCALL_TRACE))
+ if (test_thread_flag(TIF_SYSCALL_TRACE) ||
+ test_thread_flag(TIF_SYSCALL_EMU)) {
tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
+ if (!in_syscall(regs) || test_thread_flag(TIF_SYSCALL_EMU))
+ return -1;
+ }
/* Do the secure computing after ptrace; failures should be fast. */
if (secure_computing(NULL) == -1)
--
2.17.1
