Merge branch irq/remove-handle-domain-irq-20211026 into irq/irqchip-next

* irq/remove-handle-domain-irq-20211026:
  : Large rework of the architecture entry code from Mark Rutland.
  : From the cover letter:
  :
  : <quote>
  : The handle_domain_{irq,nmi}() functions were oringally intended as a
  : convenience, but recent rework to entry code across the kernel tree has
  : demonstrated that they cause more pain than they're worth and prevent
  : architectures from being able to write robust entry code.
  :
  : This series reworks the irq code to remove them, handling the necessary
  : entry work consistently in entry code (be it architectural or generic).
  : </quote>
  MIPS: irq: Avoid an unused-variable error
  irq: remove handle_domain_{irq,nmi}()
  irq: remove CONFIG_HANDLE_DOMAIN_IRQ_IRQENTRY
  irq: riscv: perform irqentry in entry code
  irq: openrisc: perform irqentry in entry code
  irq: csky: perform irqentry in entry code
  irq: arm64: perform irqentry in entry code
  irq: arm: perform irqentry in entry code
  irq: add a (temporary) CONFIG_HANDLE_DOMAIN_IRQ_IRQENTRY
  irq: nds32: avoid CONFIG_HANDLE_DOMAIN_IRQ
  irq: arc: avoid CONFIG_HANDLE_DOMAIN_IRQ
  irq: add generic_handle_arch_irq()
  irq: unexport handle_irq_desc()
  irq: simplify handle_domain_{irq,nmi}()
  irq: mips: simplify do_domain_IRQ()
  irq: mips: stop (ab)using handle_domain_irq()
  irq: mips: simplify bcm6345_l1_irq_handle()
  irq: mips: avoid nested irq_enter()

Signed-off-by: Marc Zyngier <maz@kernel.org>

2 files changed, 31 insertions, 22 deletions

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 5c7ae4c3954b..e6593a03ea27 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -133,7 +133,6 @@ config ARM64
 	select GENERIC_TIME_VSYSCALL
 	select GENERIC_GETTIMEOFDAY
 	select GENERIC_VDSO_TIME_NS
-	select HANDLE_DOMAIN_IRQ
 	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 32f9796c4ffe..f7408edf8571 100644
--- 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);
 }