Commit 26dc1293 authored by Mark Rutland's avatar Mark Rutland
Browse files

irq: arm64: perform irqentry in entry code 



In preparation for removing HANDLE_DOMAIN_IRQ_IRQENTRY, have arch/arm64
perform all the irqentry accounting in its entry code.

As arch/arm64 already performs portions of the irqentry logic in
enter_from_kernel_mode() and exit_to_kernel_mode(), including
rcu_irq_{enter,exit}(), the only additional calls that need to be made
are to irq_{enter,exit}_rcu(). Removing the calls to
rcu_irq_{enter,exit}() from handle_domain_irq() ensures that we inform
RCU once per IRQ entry and will correctly identify quiescent periods.

Since we should not call irq_{enter,exit}_rcu() when entering a
pseudo-NMI, el1_interrupt() is reworked to have separate __el1_irq() and
__el1_pnmi() paths for regular IRQ and psuedo-NMI entry, with
irq_{enter,exit}_irq() only called for the former.

In preparation for removing HANDLE_DOMAIN_IRQ, the irq regs are managed
in do_interrupt_handler() for both regular IRQ and pseudo-NMI. This is
currently redundant, but not harmful.

For clarity the preemption logic is moved into __el1_irq(). We should
never preempt within a pseudo-NMI, and arm64_enter_nmi() already
enforces this by incrementing the preempt_count, but it's clearer if we
never invoke the preemption logic when entering a pseudo-NMI.

Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
Reviewed-by: default avatarPingfan Liu <kernelfans@gmail.com>
Reviewed-by: default avatarMarc Zyngier <maz@kernel.org>
Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
parent a7b0872e

arch/arm64/Kconfig

+0 −1
Original line number Diff line number Diff line
@@ -134,7 +134,6 @@ 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/arm64/kernel/entry-common.c

+31 −21
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <asm/daifflags.h>

#include <asm/esr.h>

#include <asm/exception.h>

#include <asm/irq_regs.h>

#include <asm/kprobes.h>

#include <asm/mmu.h>

#include <asm/processor.h>
@@ -219,22 +220,6 @@ static void noinstr arm64_exit_el1_dbg(struct pt_regs *regs) 
		lockdep_hardirqs_on(CALLER_ADDR0);

}



static void noinstr enter_el1_irq_or_nmi(struct pt_regs *regs)

{

	if (IS_ENABLED(CONFIG_ARM64_PSEUDO_NMI) && !interrupts_enabled(regs))

		arm64_enter_nmi(regs);

	else

		enter_from_kernel_mode(regs);

}



static void noinstr exit_el1_irq_or_nmi(struct pt_regs *regs)

{

	if (IS_ENABLED(CONFIG_ARM64_PSEUDO_NMI) && !interrupts_enabled(regs))

		arm64_exit_nmi(regs);

	else

		exit_to_kernel_mode(regs);

}



static void __sched arm64_preempt_schedule_irq(void)

{

	lockdep_assert_irqs_disabled();
@@ -263,10 +248,14 @@ static void __sched arm64_preempt_schedule_irq(void) 
static void do_interrupt_handler(struct pt_regs *regs,

				 void (*handler)(struct pt_regs *))

{

	struct pt_regs *old_regs = set_irq_regs(regs);



	if (on_thread_stack())

		call_on_irq_stack(regs, handler);

	else

		handler(regs);



	set_irq_regs(old_regs);

}



extern void (*handle_arch_irq)(struct pt_regs *);
@@ -432,13 +421,22 @@ asmlinkage void noinstr el1h_64_sync_handler(struct pt_regs *regs) 
	}

}



static void noinstr el1_interrupt(struct pt_regs *regs,

static __always_inline void __el1_pnmi(struct pt_regs *regs,

				       void (*handler)(struct pt_regs *))

{

	write_sysreg(DAIF_PROCCTX_NOIRQ, daif);

	arm64_enter_nmi(regs);

	do_interrupt_handler(regs, handler);

	arm64_exit_nmi(regs);

}



	enter_el1_irq_or_nmi(regs);

static __always_inline void __el1_irq(struct pt_regs *regs,

				      void (*handler)(struct pt_regs *))

{

	enter_from_kernel_mode(regs);



	irq_enter_rcu();

	do_interrupt_handler(regs, handler);

	irq_exit_rcu();



	/*

	 * Note: thread_info::preempt_count includes both thread_info::count
@@ -449,7 +447,17 @@ static void noinstr el1_interrupt(struct pt_regs *regs, 
	    READ_ONCE(current_thread_info()->preempt_count) == 0)

		arm64_preempt_schedule_irq();



	exit_el1_irq_or_nmi(regs);

	exit_to_kernel_mode(regs);

}

static void noinstr el1_interrupt(struct pt_regs *regs,

				  void (*handler)(struct pt_regs *))

{

	write_sysreg(DAIF_PROCCTX_NOIRQ, daif);



	if (IS_ENABLED(CONFIG_ARM64_PSEUDO_NMI) && !interrupts_enabled(regs))

		__el1_pnmi(regs, handler);

	else

		__el1_irq(regs, handler);

}



asmlinkage void noinstr el1h_64_irq_handler(struct pt_regs *regs)
@@ -667,7 +675,9 @@ static void noinstr el0_interrupt(struct pt_regs *regs, 
	if (regs->pc & BIT(55))

		arm64_apply_bp_hardening();



	irq_enter_rcu();

	do_interrupt_handler(regs, handler);

	irq_exit_rcu();



	exit_to_user_mode(regs);

}