On 2025/11/19 1:10, Kevin Brodsky wrote:
In subject: s/refator/refactor/
Also nit: this is less about ptrace than about syscall entry, so maybe "arm64/syscall:"?
On 17/11/2025 14:30, Jinjie Ruan wrote:
Compared to the generic entry code, arm64 terminate the process
s/terminate/terminates/ (similar observation for other commit messages)
Will update it.
after report_syscall_exit() if the syscall is issued within a restartable sequence.
Presumably this implies that forcing SIGSEGV before or after calling the tracing handlers makes no difference, if so it should be clarified.
It seems that it need a separate patch to clarify.
In preparation for moving arm64 over to the generic entry code, refactor el0_svc_common() as below:
Extract syscall_exit_to_user_mode_prepare() to replace the the combination of read_thread_flags() and syscall_trace_exit(), also move the syscall exit check logic into it.
Move rseq_syscall() ahead, so the CONFIG_DEBUG_RSEQ check is not needed.
Move has_syscall_work() helper into asm/syscall.h, which will be reused by ptrace.c.
Signed-off-by: Jinjie Ruan ruanjinjie@huawei.com
arch/arm64/include/asm/syscall.h | 7 ++++++- arch/arm64/kernel/ptrace.c | 10 +++++++++- arch/arm64/kernel/syscall.c | 26 +++++--------------------- 3 files changed, 20 insertions(+), 23 deletions(-)
diff --git a/arch/arm64/include/asm/syscall.h b/arch/arm64/include/asm/syscall.h index d69f590a989b..6225981fbbdb 100644 --- a/arch/arm64/include/asm/syscall.h +++ b/arch/arm64/include/asm/syscall.h @@ -114,7 +114,12 @@ static inline int syscall_get_arch(struct task_struct *task) return AUDIT_ARCH_AARCH64; } +static inline bool has_syscall_work(unsigned long flags) +{
- return unlikely(flags & _TIF_SYSCALL_WORK);
+}
int syscall_trace_enter(struct pt_regs *regs, long syscall, unsigned long flags); -void syscall_trace_exit(struct pt_regs *regs, unsigned long flags); +void syscall_exit_to_user_mode_prepare(struct pt_regs *regs); #endif /* __ASM_SYSCALL_H */ diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index bbb868f6b292..95984bbf53db 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -2403,7 +2403,7 @@ int syscall_trace_enter(struct pt_regs *regs, long syscall, unsigned long flags) return regs->syscallno; } -void syscall_trace_exit(struct pt_regs *regs, unsigned long flags) +static void syscall_trace_exit(struct pt_regs *regs, unsigned long flags) { audit_syscall_exit(regs); @@ -2412,8 +2412,16 @@ void syscall_trace_exit(struct pt_regs *regs, unsigned long flags) if (flags & (_TIF_SYSCALL_TRACE | _TIF_SINGLESTEP)) report_syscall_exit(regs); +}
+void syscall_exit_to_user_mode_prepare(struct pt_regs *regs) +{
- unsigned long flags = read_thread_flags();
rseq_syscall(regs);
- if (has_syscall_work(flags) || flags & _TIF_SINGLESTEP)
syscall_trace_exit(regs, flags);Since we're trying to align as much with the generic code as possible, we might as well rename this function to syscall_exit_work() as well.
Yes, syscall_trace_exit() is very similar to syscall_exit_work().
} /* diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c index 6e3fe760e0bb..9713b038d750 100644 --- a/arch/arm64/kernel/syscall.c +++ b/arch/arm64/kernel/syscall.c @@ -65,11 +65,6 @@ static void invoke_syscall(struct pt_regs *regs, unsigned int scno, choose_random_kstack_offset(get_random_u16()); } -static inline bool has_syscall_work(unsigned long flags) -{
- return unlikely(flags & _TIF_SYSCALL_WORK);
-}
static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr, const syscall_fn_t syscall_table[]) { @@ -125,26 +120,15 @@ static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr, if (scno == NO_SYSCALL) syscall_set_return_value(current, regs, -ENOSYS, 0); scno = syscall_trace_enter(regs, regs->syscallno, flags);
if (scno == NO_SYSCALL)goto trace_exit;Why not keep the goto instead of duplicating the call? It could be renamed if necessary.
That is good.
- Kevin
if (scno == NO_SYSCALL) {syscall_exit_to_user_mode_prepare(regs);return;}invoke_syscall(regs, scno, sc_nr, syscall_table);
- /*
* The tracing status may have changed under our feet, so we have to* check again. However, if we were tracing entry, then we always trace* exit regardless, as the old entry assembly did.*/- if (!has_syscall_work(flags) && !IS_ENABLED(CONFIG_DEBUG_RSEQ)) {
flags = read_thread_flags();if (!has_syscall_work(flags) && !(flags & _TIF_SINGLESTEP))return;- }
-trace_exit:
- flags = read_thread_flags();
- syscall_trace_exit(regs, flags);
- syscall_exit_to_user_mode_prepare(regs);
} void do_el0_svc(struct pt_regs *regs)