linux/kernel/irq/Kconfig
Thomas Gleixner acd26bcf36 genirq: Provide interrupt injection mechanism
Error injection mechanisms need a half ways safe way to inject interrupts as
invoking generic_handle_irq() or the actual device interrupt handler
directly from e.g. a debugfs write is not guaranteed to be safe.

On x86 generic_handle_irq() is unsafe due to the hardware trainwreck which
is the base of x86 interrupt delivery and affinity management.

Move the irq debugfs injection code into a separate function which can be
used by error injection code as well.

The implementation prevents at least that state is corrupted, but it cannot
close a very tiny race window on x86 which might result in a stale and not
serviced device interrupt under very unlikely circumstances.

This is explicitly for debugging and testing and not for production use or
abuse in random driver code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lkml.kernel.org/r/20200306130623.990928309@linutronix.de
2020-03-08 11:06:42 +01:00

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# SPDX-License-Identifier: GPL-2.0-only
menu "IRQ subsystem"
# Options selectable by the architecture code
# Make sparse irq Kconfig switch below available
config MAY_HAVE_SPARSE_IRQ
bool
# Legacy support, required for itanic
config GENERIC_IRQ_LEGACY
bool
# Enable the generic irq autoprobe mechanism
config GENERIC_IRQ_PROBE
bool
# Use the generic /proc/interrupts implementation
config GENERIC_IRQ_SHOW
bool
# Print level/edge extra information
config GENERIC_IRQ_SHOW_LEVEL
bool
# Supports effective affinity mask
config GENERIC_IRQ_EFFECTIVE_AFF_MASK
bool
# Facility to allocate a hardware interrupt. This is legacy support
# and should not be used in new code. Use irq domains instead.
config GENERIC_IRQ_LEGACY_ALLOC_HWIRQ
bool
# Support for delayed migration from interrupt context
config GENERIC_PENDING_IRQ
bool
# Support for generic irq migrating off cpu before the cpu is offline.
config GENERIC_IRQ_MIGRATION
bool
# Alpha specific irq affinity mechanism
config AUTO_IRQ_AFFINITY
bool
# Interrupt injection mechanism
config GENERIC_IRQ_INJECTION
bool
# Tasklet based software resend for pending interrupts on enable_irq()
config HARDIRQS_SW_RESEND
bool
# Preflow handler support for fasteoi (sparc64)
config IRQ_PREFLOW_FASTEOI
bool
# Edge style eoi based handler (cell)
config IRQ_EDGE_EOI_HANDLER
bool
# Generic configurable interrupt chip implementation
config GENERIC_IRQ_CHIP
bool
select IRQ_DOMAIN
# Generic irq_domain hw <--> linux irq number translation
config IRQ_DOMAIN
bool
# Support for simulated interrupts
config IRQ_SIM
bool
select IRQ_WORK
# Support for hierarchical irq domains
config IRQ_DOMAIN_HIERARCHY
bool
select IRQ_DOMAIN
# Support for hierarchical fasteoi+edge and fasteoi+level handlers
config IRQ_FASTEOI_HIERARCHY_HANDLERS
bool
# Generic IRQ IPI support
config GENERIC_IRQ_IPI
bool
# Generic MSI interrupt support
config GENERIC_MSI_IRQ
bool
# Generic MSI hierarchical interrupt domain support
config GENERIC_MSI_IRQ_DOMAIN
bool
select IRQ_DOMAIN_HIERARCHY
select GENERIC_MSI_IRQ
config IRQ_MSI_IOMMU
bool
config HANDLE_DOMAIN_IRQ
bool
config IRQ_TIMINGS
bool
config GENERIC_IRQ_MATRIX_ALLOCATOR
bool
config GENERIC_IRQ_RESERVATION_MODE
bool
# Support forced irq threading
config IRQ_FORCED_THREADING
bool
config SPARSE_IRQ
bool "Support sparse irq numbering" if MAY_HAVE_SPARSE_IRQ
---help---
Sparse irq numbering is useful for distro kernels that want
to define a high CONFIG_NR_CPUS value but still want to have
low kernel memory footprint on smaller machines.
( Sparse irqs can also be beneficial on NUMA boxes, as they spread
out the interrupt descriptors in a more NUMA-friendly way. )
If you don't know what to do here, say N.
config GENERIC_IRQ_DEBUGFS
bool "Expose irq internals in debugfs"
depends on DEBUG_FS
select GENERIC_IRQ_INJECTION
default n
---help---
Exposes internal state information through debugfs. Mostly for
developers and debugging of hard to diagnose interrupt problems.
If you don't know what to do here, say N.
endmenu
config GENERIC_IRQ_MULTI_HANDLER
bool
help
Allow to specify the low level IRQ handler at run time.