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: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Pingfan Liu <kernelfans@gmail.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 553239a..5c7ae4c 100644 (file)
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -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

diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c
index 32f9796..f7408ed 100644 (file)
--- a/arch/arm64/kernel/entry-common.c
+++ b/arch/arm64/kernel/entry-common.c
@@ -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,
-                                 void (*handler)(struct pt_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);
+}
+
+static __always_inline void __el1_irq(struct pt_regs *regs,
+                                     void (*handler)(struct pt_regs *))
+{
+       enter_from_kernel_mode(regs);
 
-       enter_el1_irq_or_nmi(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);
 }