commit acd26bcf362708594ea081ef55140e37d0854ed2 upstream.
Backport summary: for 5.4 kernel ICX PCIe Gen4 support.
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
(cherry picked from commit acd26bcf362708594ea081ef55140e37d0854ed2)
Signed-off-by: Ethan Zhao <haifeng.zhao@intel.com>
commit 1f85b1f5e1f5541272abedc19ba7b6c5b564c228 upstream.
Backport summary: for 5.4 kernel ICX PCIe Gen4 support.
In preparation for an interrupt injection interface which can be used
safely by error injection mechanisms. e.g. PCI-E/ AER, add a return value
to check_irq_resend() so errors can be propagated to the caller.
Split out the software resend code so the ugly #ifdef in check_irq_resend()
goes away and the whole thing becomes readable.
Fix up the caller in debugfs. The caller in irq_startup() does not care
about the return value as this is unconditionally invoked for all
interrupts and the resend is best effort anyway.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lkml.kernel.org/r/20200306130623.775200917@linutronix.de
(cherry picked from commit 1f85b1f5e1f5541272abedc19ba7b6c5b564c228)
Signed-off-by: Ethan Zhao <haifeng.zhao@intel.com>
Thomas Gleixner