linux-stable.git/arch/mips/kernel/irq.c, branch linux-rolling-stable

MIPS: irq: Avoid an unused-variable error

2021-10-28T12:28:52+00:00

When CONFIG_IRQ_DOMAIN is set, there is a warning:
arch/mips/kernel/irq.c:114:19: error: unused variable 'desc' [-Werror=unused-variable]
  114 |  struct irq_desc *desc;
      |                   ^~~~

This variable is unused, let's remove it.

Signed-off-by: Yanteng Si 
Signed-off-by: Marc Zyngier 
Link: https://lore.kernel.org/r/20211028095652.3503790-1-siyanteng@loongson.cn

irq: mips: simplify do_domain_IRQ()

2021-10-25T09:05:08+00:00

There's no need fpr arch/mips's do_domain_IRQ() to open-code the NULL
check performed by handle_irq_desc(), nor the resolution of the desc
performed by generic_handle_domain_irq().

Use generic_handle_domain_irq() directly, as this is functioanlly
equivalent and clearer.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland 
Reviewed-by: Marc Zyngier 
Acked-by: Thomas Bogendoerfer 
Cc: Thomas Gleixner

irqchip/mips: Fix RCU violation when using irqdomain lookup on interrupt entry

2021-07-09T09:18:58+00:00

Since d4a45c68dc81 ("irqdomain: Protect the linear revmap with RCU"),
any irqdomain lookup requires the RCU read lock to be held.

This assumes that the architecture code will be structured such as
irq_enter() will be called *before* the interrupt is looked up
in the irq domain. However, this isn't the case for MIPS, and a number
of drivers are structured to do it the other way around when handling
an interrupt in their root irqchip (secondary irqchips are OK by
construction).

This results in a RCU splat on a lockdep-enabled kernel when the kernel
takes an interrupt from idle, as reported by Guenter Roeck.

Note that this could have fired previously if any driver had used
tree-based irqdomain, which always had the RCU requirement.

To solve this, provide a MIPS-specific helper (do_domain_IRQ())
as the pendent of do_IRQ() that will do thing in the right order
(and maybe save some cycles in the process).

Ideally, MIPS would be moved over to using handle_domain_irq(),
but that's much more ambitious.

Reported-by: Guenter Roeck 
Tested-by: Guenter Roeck 
[maz: add dependency on CONFIG_IRQ_DOMAIN after report from the kernelci bot]
Signed-off-by: Marc Zyngier 
Cc: Thomas Bogendoerfer 
Cc: Serge Semin 
Link: https://lore.kernel.org/r/20210705172352.GA56304@roeck-us.net
Link: https://lore.kernel.org/r/20210706110647.3979002-1-maz@kernel.org

MIPS: irq: Allocate accurate order pages for irq stack

2019-02-19T20:45:01+00:00

The irq_pages is the number of pages for irq stack, but not the
order which is needed by __get_free_pages().
We can use get_order() to calculate the accurate order.

Signed-off-by: Liu Xiang 
Signed-off-by: Paul Burton 
Fixes: fe8bd18ffea5 ("MIPS: Introduce irq_stack")
Cc: linux-mips@vger.kernel.org
Cc: stable@vger.kernel.org # v4.11+

MIPS: Introduce irq_stack

2017-01-03T15:34:34+00:00

Allocate a per-cpu irq stack for use within interrupt handlers.

Also add a utility function on_irq_stack to determine if a given stack
pointer is within the irq stack for that cpu.

Signed-off-by: Matt Redfearn 
Acked-by: Jason A. Donenfeld 
Cc: Thomas Gleixner 
Cc: Paolo Bonzini 
Cc: Chris Metcalf 
Cc: Petr Mladek 
Cc: James Hogan 
Cc: Paul Burton 
Cc: Aaron Tomlin 
Cc: Andrew Morton 
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14740/
Signed-off-by: Ralf Baechle

Replace with globally

2016-12-24T19:46:01+00:00

This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*'
  sed -i -e "s!$PATT!#include !" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro 
Signed-off-by: Linus Torvalds

MIPS: Clear Status IPL field when using EIC

2016-05-28T10:35:02+00:00

When using an external interrupt controller (EIC) the interrupt mask
bits in the cop0 Status register are reused for the Interrupt Priority
Level, and any interrupts with a priority lower than the field will be
ignored. Clear the field to 0 by default such that all interrupts are
serviced. Without doing so we default to arbitrarily ignoring all or
some subset of interrupts.

Signed-off-by: Paul Burton 
Reviewed-by: Matt Redfearn 
Tested-by: Matt Redfearn 
Cc: Guenter Roeck 
Cc: Sergei Shtylyov 
Cc: Joe Perches 
Cc: James Hogan 
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13272/
Signed-off-by: Ralf Baechle

MIPS: IRQ/IP27: Move IRQ allocation API to platform code.

2015-06-21T19:54:31+00:00

allocate_irqno, free_irqno and alloc_legacy_irqno are a simple allocator
for interrupt numbers from the days when the numer of interrupts was still
fixed to NR_IRQS.  This was necessary for the SGI IP27 architecture which
with its flexible architecture and possibly large number of interrupts
doesn't easily fit into the old pattern.  These days there are better
alternatives.

Move the allocation code from the arch generic code to the only platform
using it, the SGI IP27 aka Origin 200/2000, Onyx 2.

Signed-off-by: Ralf Baechle

MIPS: Get rid of 'kgdb_early_setup' cruft.

2015-06-21T19:54:10+00:00

Commit 854700115ecf ([MIPS] kgdb: add arch support for the kernel's kgdb core)
added the 'kgdb_early_setup' flag to avoid  calling trap_init() and init_IRQ()
the second time, however the code that called these functions earlier,  from
kgdb_arch_init(), had been already removed by that  time,  so the flag never
served any useful purpose. Remove the related code along with ugly #ifdef'ery
at last.

[ralf@linux-mips.org: Folded in Guenter Roeck's fix.]

Signed-off-by: Sergei Shtylyov 
Patchwork: https://patchwork.linux-mips.org/patch/10501/
Signed-off-by: Guenter Roeck 
Patchwork: https://patchwork.linux-mips.org/patch/10533/
Signed-off-by: Ralf Baechle

MIPS: Fix enabling of DEBUG_STACKOVERFLOW

2015-06-06T08:21:09+00:00

Commit 334c86c494b9 ("MIPS: IRQ: Add stackoverflow detection") added
kernel stack overflow detection, however it only enabled it conditional
upon the preprocessor definition DEBUG_STACKOVERFLOW, which is never
actually defined. The Kconfig option is called DEBUG_STACKOVERFLOW,
which manifests to the preprocessor as CONFIG_DEBUG_STACKOVERFLOW, so
switch it to using that definition instead.

Fixes: 334c86c494b9 ("MIPS: IRQ: Add stackoverflow detection")
Signed-off-by: James Hogan 
Cc: Ralf Baechle 
Cc: Adam Jiang 
Cc: linux-mips@linux-mips.org
Cc:  # 2.6.37+
Patchwork: http://patchwork.linux-mips.org/patch/10531/
Signed-off-by: Ralf Baechle