On Wed, 2021-07-07 at 22:16 +0200, Jan Kiszka via Xenomai wrote:
> From: Jan Kiszka <[email protected]>
>
> Setting XNDBGCTRL for a thread will prevent its migration to secondary
> if only the debugging signals SIGINT or SIGSTOP are pending. Such
> threads will still be able to trigger migration on other signals, such
> as SIGDEBUG (watchdog), SIGCANCEL (SIGRTMIN) or synchronous SIGTRAP.
>
> This is a building block for the debug helper feature.
>
> Signed-off-by: Jan Kiszka <[email protected]>
> ---
> include/cobalt/uapi/kernel/thread.h | 1 +
> kernel/cobalt/posix/syscall.c | 12 +++++++++++-
> 2 files changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/include/cobalt/uapi/kernel/thread.h
> b/include/cobalt/uapi/kernel/thread.h
> index 664def08ef..74007ac0d6 100644
> --- a/include/cobalt/uapi/kernel/thread.h
> +++ b/include/cobalt/uapi/kernel/thread.h
> @@ -51,6 +51,7 @@
> #define XNTRAPLB 0x00100000 /**< Trap lock break (i.e. may not sleep with
> sched lock) */
> #define XNDEBUG 0x00200000 /**< User-level debugging enabled */
> #define XNDBGSTOP 0x00400000 /**< Stopped for synchronous debugging */
> +#define XNDBGCTRL 0x00800000 /**< Thread is protected against SIGSTOP/SIGINT
> */
>
>
>
>
> /** @} */
>
>
>
>
> diff --git a/kernel/cobalt/posix/syscall.c b/kernel/cobalt/posix/syscall.c
> index cd72b22d14..618f965c2a 100644
> --- a/kernel/cobalt/posix/syscall.c
> +++ b/kernel/cobalt/posix/syscall.c
> @@ -86,6 +86,8 @@ static void prepare_for_signal(struct task_struct *p,
> struct pt_regs *regs,
> int sysflags)
> {
> + sigset_t pending;
> + int ignore = 0;
Why not bool?
> int notify = 0;
> spl_t s;
>
>
>
>
> @@ -100,13 +102,21 @@ static void prepare_for_signal(struct task_struct *p,
> xnthread_clear_info(thread, XNBREAK);
> }
> xnthread_clear_info(thread, XNKICKED);
> + } else if (xnthread_test_state(thread, XNDBGCTRL)) {
> + /* only ignore thread-specific SIGSTOP/SIGINT */
> + pending = p->pending.signal;
> + sigdelset(&pending, SIGSTOP);
> + sigdelset(&pending, SIGINT);
> + if (sigisemptyset(&pending))
> + ignore = 1;
> }
>
>
>
>
> xnlock_put_irqrestore(&nklock, s);
>
>
>
>
> xnthread_test_cancel();
>
>
>
>
> - xnthread_relax(notify, SIGDEBUG_MIGRATE_SIGNAL);
> + if (!ignore)
> + xnthread_relax(notify, SIGDEBUG_MIGRATE_SIGNAL);
> }
>
>
>
>
> static COBALT_SYSCALL(migrate, current, (int domain))
