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| author | Johannes Berg <johannes.berg@intel.com> | 2021-03-05 15:19:56 +0300 |
|---|---|---|
| committer | Richard Weinberger <richard@nod.at> | 2021-06-17 22:44:52 +0300 |
| commit | d6b399a0e02a9063a5812af6cb8b657a4a1ecf68 (patch) | |
| tree | 88ffd20ce7a78849df5f2a542942d62e757558e0 /arch/um/include | |
| parent | 33c7d0616a0482def19d7f981d4eaa429086c771 (diff) | |
| download | linux-d6b399a0e02a9063a5812af6cb8b657a4a1ecf68.tar.xz | |
um: time-travel/signals: fix ndelay() in interrupt
We should be able to ndelay() from any context, even from an
interrupt context! However, this is broken (not functionally,
but locking-wise) in time-travel because we'll get into the
time-travel code and enable interrupts to handle messages on
other time-travel aware subsystems (only virtio for now).
Luckily, I've already reworked the time-travel aware signal
(interrupt) delivery for suspend/resume to have a time travel
handler, which runs directly in the context of the signal and
not from the Linux interrupt.
In order to fix this time-travel issue then, we need to do a
few things:
1) rework the signal handling code to call time-travel handlers
(only) if interrupts are disabled but signals aren't blocked,
instead of marking it only pending there. This is needed to
not deadlock other communication.
2) rework time-travel to not enable interrupts while it's
waiting for a message;
3) rework time-travel to not (just) disable interrupts but
rather block signals at a lower level while it needs them
disabled for communicating with the controller.
Finally, since now we can actually spend even virtual time
in interrupts-disabled sections, the delay warning when we
deliver a time-travel delayed interrupt is no longer valid,
things can (and should) now get delayed.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Diffstat (limited to 'arch/um/include')
| -rw-r--r-- | arch/um/include/shared/irq_user.h | 1 | ||||
| -rw-r--r-- | arch/um/include/shared/os.h | 3 |
2 files changed, 4 insertions, 0 deletions
diff --git a/arch/um/include/shared/irq_user.h b/arch/um/include/shared/irq_user.h index 07239e801a5b..065829f443ae 100644 --- a/arch/um/include/shared/irq_user.h +++ b/arch/um/include/shared/irq_user.h @@ -17,6 +17,7 @@ enum um_irq_type { struct siginfo; extern void sigio_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs); +void sigio_run_timetravel_handlers(void); extern void free_irq_by_fd(int fd); extern void deactivate_fd(int fd, int irqnum); extern int deactivate_all_fds(void); diff --git a/arch/um/include/shared/os.h b/arch/um/include/shared/os.h index f9fbbddc38bb..453b13369533 100644 --- a/arch/um/include/shared/os.h +++ b/arch/um/include/shared/os.h @@ -242,6 +242,9 @@ extern int set_signals_trace(int enable); extern int os_is_signal_stack(void); extern void deliver_alarm(void); extern void register_pm_wake_signal(void); +extern void block_signals_hard(void); +extern void unblock_signals_hard(void); +extern void mark_sigio_pending(void); /* util.c */ extern void stack_protections(unsigned long address); |