On 17/11/2025 14:30, Jinjie Ruan wrote:
> The generic syscall entry code has the form:
>
> | syscall_trace_enter()
> | {
> | ptrace_report_syscall_entry()
> | }
> |
> | syscall_exit_work()
> | {
> | ptrace_report_syscall_exit()
> | }
>
> In preparation for moving arm64 over to the generic entry code, split
> report_syscall() to two separate enter and exit functions to align
> the structure of the arm64 code with syscall_trace_enter() and
> syscall_exit_work() from the generic entry code.
>
> No functional changes.
>
> Suggested-by: Mark Rutland <[email protected]>
> Signed-off-by: Jinjie Ruan <[email protected]>
> ---
> arch/arm64/kernel/ptrace.c | 29 ++++++++++++++++++++---------
> 1 file changed, 20 insertions(+), 9 deletions(-)
>
> diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
> index 4b001121c72d..5534c175ceb7 100644
> --- a/arch/arm64/kernel/ptrace.c
> +++ b/arch/arm64/kernel/ptrace.c
> @@ -2317,7 +2317,7 @@ enum ptrace_syscall_dir {
> PTRACE_SYSCALL_EXIT,
> };
This is now unused so it should be removed.
>
> -static void report_syscall(struct pt_regs *regs, enum ptrace_syscall_dir dir)
> +static void report_syscall_enter(struct pt_regs *regs)
Nit: better to call it "report_syscall_entry" to match its final name.
> {
> int regno;
> unsigned long saved_reg;
> @@ -2340,13 +2340,24 @@ static void report_syscall(struct pt_regs *regs, enum
> ptrace_syscall_dir dir)
> */
> regno = (is_compat_task() ? 12 : 7);
> saved_reg = regs->regs[regno];
> - regs->regs[regno] = dir;
> + regs->regs[regno] = PTRACE_SYSCALL_ENTER;
>
> - if (dir == PTRACE_SYSCALL_ENTER) {
> - if (ptrace_report_syscall_entry(regs))
> - forget_syscall(regs);
> - regs->regs[regno] = saved_reg;
> - } else if (!test_thread_flag(TIF_SINGLESTEP)) {
> + if (ptrace_report_syscall_entry(regs))
> + forget_syscall(regs);
> + regs->regs[regno] = saved_reg;
> +}
> +
> +static void report_syscall_exit(struct pt_regs *regs)
> +{
> + int regno;
> + unsigned long saved_reg;
> +
> + /* See comment for report_syscall_enter() above */
> + regno = (is_compat_task() ? 12 : 7);
Probably best not to duplicate such magic numbers, moving this line to a
helper would be good.
- Kevin
> + saved_reg = regs->regs[regno];
> + regs->regs[regno] = PTRACE_SYSCALL_EXIT;
> +
> + if (!test_thread_flag(TIF_SINGLESTEP)) {
> ptrace_report_syscall_exit(regs, 0);
> regs->regs[regno] = saved_reg;
> } else {
> @@ -2366,7 +2377,7 @@ int syscall_trace_enter(struct pt_regs *regs)
> unsigned long flags = read_thread_flags();
>
> if (flags & (_TIF_SYSCALL_EMU | _TIF_SYSCALL_TRACE)) {
> - report_syscall(regs, PTRACE_SYSCALL_ENTER);
> + report_syscall_enter(regs);
> if (flags & _TIF_SYSCALL_EMU)
> return NO_SYSCALL;
> }
> @@ -2394,7 +2405,7 @@ void syscall_trace_exit(struct pt_regs *regs)
> trace_sys_exit(regs, syscall_get_return_value(current, regs));
>
> if (flags & (_TIF_SYSCALL_TRACE | _TIF_SINGLESTEP))
> - report_syscall(regs, PTRACE_SYSCALL_EXIT);
> + report_syscall_exit(regs);
>
> rseq_syscall(regs);
> }
