Commit 2fe35f8e authored by Mark Rutland's avatar Mark Rutland
Browse files

irq: add a (temporary) CONFIG_HANDLE_DOMAIN_IRQ_IRQENTRY 



Going forward we want architecture/entry code to perform all the
necessary work to enter/exit IRQ context, with irqchip code merely
handling the mapping of the interrupt to any handler(s). Among other
reasons, this is necessary to consistently fix some longstanding issues
with the ordering of lockdep/RCU/tracing instrumentation which many
architectures get wrong today in their entry code.

Importantly, rcu_irq_{enter,exit}() must be called precisely once per
IRQ exception, so that rcu_is_cpu_rrupt_from_idle() can correctly
identify when an interrupt was taken from an idle context which must be
explicitly preempted. Currently handle_domain_irq() calls
rcu_irq_{enter,exit}() via irq_{enter,exit}(), but entry code needs to
be able to call rcu_irq_{enter,exit}() earlier for correct ordering
across lockdep/RCU/tracing updates for sequences such as:

  lockdep_hardirqs_off(CALLER_ADDR0);
  rcu_irq_enter();
  trace_hardirqs_off_finish();

To permit each architecture to be converted to the new style in turn,
this patch adds a new CONFIG_HANDLE_DOMAIN_IRQ_IRQENTRY selected by all
current users of HANDLE_DOMAIN_IRQ, which gates the existing behaviour.
When CONFIG_HANDLE_DOMAIN_IRQ_IRQENTRY is not selected,
handle_domain_irq() requires entry code to perform the
irq_{enter,exit}() work, with an explicit check for this matching the
style of handle_domain_nmi().

Subsequent patches will:

1) Add the necessary IRQ entry accounting to each architecture in turn,
   dropping CONFIG_HANDLE_DOMAIN_IRQ_IRQENTRY from that architecture's
   Kconfig.

2) Remove CONFIG_HANDLE_DOMAIN_IRQ_IRQENTRY once it is no longer
   selected.

3) Convert irqchip drivers to consistently use
   generic_handle_domain_irq() rather than handle_domain_irq().

4) Remove handle_domain_irq() and CONFIG_HANDLE_DOMAIN_IRQ.

... which should leave us with a clear split of responsiblity across the
entry and irqchip code, making it possible to perform additional
cleanups and fixes for the aforementioned longstanding issues with entry
code.

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

Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
Reviewed-by: default avatarMarc Zyngier <maz@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
parent 6f877e13

arch/arm/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -65,6 +65,7 @@ config ARM 
	select GENERIC_SCHED_CLOCK

	select GENERIC_SMP_IDLE_THREAD

	select HANDLE_DOMAIN_IRQ

	select HANDLE_DOMAIN_IRQ_IRQENTRY

	select HARDIRQS_SW_RESEND

	select HAVE_ARCH_AUDITSYSCALL if AEABI && !OABI_COMPAT

	select HAVE_ARCH_BITREVERSE if (CPU_32v7M || CPU_32v7) && !CPU_32v6

arch/arm64/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -134,6 +134,7 @@ config ARM64 
	select GENERIC_GETTIMEOFDAY

	select GENERIC_VDSO_TIME_NS

	select HANDLE_DOMAIN_IRQ

	select HANDLE_DOMAIN_IRQ_IRQENTRY

	select HARDIRQS_SW_RESEND

	select HAVE_MOVE_PMD

	select HAVE_MOVE_PUD

arch/csky/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ config CSKY 
	select DMA_DIRECT_REMAP

	select IRQ_DOMAIN

	select HANDLE_DOMAIN_IRQ

	select HANDLE_DOMAIN_IRQ_IRQENTRY

	select DW_APB_TIMER_OF

	select GENERIC_IOREMAP

	select GENERIC_LIB_ASHLDI3

arch/openrisc/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ config OPENRISC 
	select OF_EARLY_FLATTREE

	select IRQ_DOMAIN

	select HANDLE_DOMAIN_IRQ

	select HANDLE_DOMAIN_IRQ_IRQENTRY

	select GPIOLIB

	select HAVE_ARCH_TRACEHOOK

	select SPARSE_IRQ

arch/riscv/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -63,6 +63,7 @@ config RISCV 
	select GENERIC_SMP_IDLE_THREAD

	select GENERIC_TIME_VSYSCALL if MMU && 64BIT

	select HANDLE_DOMAIN_IRQ

	select HANDLE_DOMAIN_IRQ_IRQENTRY

	select HAVE_ARCH_AUDITSYSCALL

	select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL

	select HAVE_ARCH_JUMP_LABEL_RELATIVE if !XIP_KERNEL