From 2fe35f8ee726466f0898ba60c5868c6f9a1ac566 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Tue, 19 Oct 2021 11:12:31 +0100 Subject: 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 Reviewed-by: Marc Zyngier Cc: Thomas Gleixner --- arch/arm64/Kconfig | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/arm64/Kconfig') diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 5c7ae4c3954b..553239a5a5f7 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -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 -- cgit v1.2.3