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authorMark Rutland <mark.rutland@arm.com>2021-10-19 11:12:31 +0100
committerMark Rutland <mark.rutland@arm.com>2021-10-25 10:05:30 +0100
commit2fe35f8ee726466f0898ba60c5868c6f9a1ac566 (patch)
tree9c2a1738cb5573a33d7c7b37b8432426e14262f4 /arch/riscv
parent6f877e13c24d8b7b96a2f4e78f13a2bdfd401c8b (diff)
downloadlinux-2fe35f8ee726466f0898ba60c5868c6f9a1ac566.tar.bz2
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: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Marc Zyngier <maz@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/riscv')
-rw-r--r--arch/riscv/Kconfig1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 301a54233c7e..740653063a56 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -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