L4Re Operating System Framework
Interface and Usage Documentation
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Interface for sending an unmask message to an object. More...
#include <irq>
Public Member Functions | |
l4_msgtag_t | unmask (unsigned irqnum, l4_umword_t *label=0, l4_timeout_t to=L4_IPC_NEVER, l4_utcb_t *utcb=l4_utcb()) noexcept |
Unmask the given interrupt line. | |
Interface for sending an unmask message to an object.
The object is usually an ICU or an IRQ.
When the kernel receives an IRQ, it masks the interrupt line at the interrupt controller and immediately acknowledges the interrupt. This interface is used to let the kernel know that userspace has dealt with the IRQ. The kernel will unmask the interrupt line and further IRQs can then be delivered.
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inlinenoexcept |
Unmask the given interrupt line.
When the object is an IRQ, the given interrupt line is ignored and instead the line which the IRQ is bound to (if any) is unmasked.
Its counterpart for explicitly masking an interrupt line is L4::Icu::mask().
irqnum | The interrupt line that shall be unmasked. Ignored if the object is an IRQ. | |
[out] | label | If NULL, this is a send-only unmask. If not NULL, this operation enters an open wait and the protected label shall be received here. |
to | The timeout-pair (send and receive) that shall be used for this operation. The receive timeout is used with a non-NULL label only. | |
utcb | UTCB to be used for this operation, shall be the UTCB of the calling thread. See l4_utcb. |
label
is NULL, this function performs an IPC send-only operation and there is no return value except L4_MSGTAG_ERROR indicating success or failure of the send operation. In this case use l4_ipc_error() to check for errors and do not use l4_error().