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) > 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. > 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 <[email protected]> > --- > 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. > } > > /* > 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. - 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)
