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 <[email protected]>

Author: Marc Zyngier

Documentation/core-api/irq/irq-domain.rst

@@ -67,9 +67,6 @@ variety of methods:
   deprecated
 - generic_handle_domain_irq() handles an interrupt described by a
   domain and a hwirq number
-- handle_domain_irq() does the same thing for root interrupt
-  controllers and deals with the set_irq_reg()/irq_enter() sequences
-  that most architecture requires
 
 Note that irq domain lookups must happen in contexts that are
 compatible with a RCU read-side critical section.

arch/arc/Kconfig

@@ -40,7 +40,6 @@ config ARC
 	select HAVE_KRETPROBES
 	select HAVE_MOD_ARCH_SPECIFIC
 	select HAVE_PERF_EVENTS
-	select HANDLE_DOMAIN_IRQ
 	select IRQ_DOMAIN
 	select MODULES_USE_ELF_RELA
 	select OF

arch/arc/kernel/irq.c

@@ -6,6 +6,8 @@
 #include <linux/interrupt.h>
 #include <linux/irqchip.h>
 #include <asm/mach_desc.h>
+
+#include <asm/irq_regs.h>
 #include <asm/smp.h>
 
 /*
@@ -39,5 +41,11 @@ void __init init_IRQ(void)
  */
 void arch_do_IRQ(unsigned int hwirq, struct pt_regs *regs)
 {
-	handle_domain_irq(NULL, hwirq, regs);
+	struct pt_regs *old_regs;
+
+	irq_enter();
+	old_regs = set_irq_regs(regs);
+	generic_handle_domain_irq(NULL, hwirq);
+	set_irq_regs(old_regs);
+	irq_exit();
 }

arch/arm/Kconfig

@@ -64,7 +64,6 @@ config ARM
 	select GENERIC_PCI_IOMAP
 	select GENERIC_SCHED_CLOCK
 	select GENERIC_SMP_IDLE_THREAD
-	select HANDLE_DOMAIN_IRQ
 	select HARDIRQS_SW_RESEND
 	select HAVE_ARCH_AUDITSYSCALL if AEABI && !OABI_COMPAT
 	select HAVE_ARCH_BITREVERSE if (CPU_32v7M || CPU_32v7) && !CPU_32v6

arch/arm/kernel/entry-armv.S

@@ -38,14 +38,11 @@
  */
 	.macro	irq_handler
 #ifdef CONFIG_GENERIC_IRQ_MULTI_HANDLER
-	ldr	r1, =handle_arch_irq
 	mov	r0, sp
-	badr	lr, 9997f
-	ldr	pc, [r1]
+	bl	generic_handle_arch_irq
 #else
 	arch_irq_handler_default
 #endif
-9997:
 	.endm
 
 	.macro	pabt_helper

arch/arm/kernel/irq.c

@@ -63,11 +63,8 @@ int arch_show_interrupts(struct seq_file *p, int prec)
  */
 void handle_IRQ(unsigned int irq, struct pt_regs *regs)
 {
-	struct pt_regs *old_regs = set_irq_regs(regs);
 	struct irq_desc *desc;
 
-	irq_enter();
-
 	/*
 	 * Some hardware gives randomly wrong interrupts.  Rather
 	 * than crashing, do something sensible.
@@ -81,9 +78,6 @@ void handle_IRQ(unsigned int irq, struct pt_regs *regs)
 		handle_irq_desc(desc);
 	else
 		ack_bad_irq(irq);
-
-	irq_exit();
-	set_irq_regs(old_regs);
 }
 
 /*
@@ -92,7 +86,15 @@ void handle_IRQ(unsigned int irq, struct pt_regs *regs)
 asmlinkage void __exception_irq_entry
 asm_do_IRQ(unsigned int irq, struct pt_regs *regs)
 {
+	struct pt_regs *old_regs;
+
+	irq_enter();
+	old_regs = set_irq_regs(regs);
+
 	handle_IRQ(irq, regs);
+
+	set_irq_regs(old_regs);
+	irq_exit();
 }
 
 void __init init_IRQ(void)

arch/arm/mach-imx/avic.c

@@ -154,7 +154,7 @@ static void __exception_irq_entry avic_handle_irq(struct pt_regs *regs)
 		if (nivector == 0xffff)
 			break;
 
-		handle_domain_irq(domain, nivector, regs);
+		generic_handle_domain_irq(domain, nivector);
 	} while (1);
 }
 

arch/arm/mach-imx/tzic.c

@@ -134,7 +134,7 @@ static void __exception_irq_entry tzic_handle_irq(struct pt_regs *regs)
 			while (stat) {
 				handled = 1;
 				irqofs = fls(stat) - 1;
-				handle_domain_irq(domain, irqofs + i * 32, regs);
+				generic_handle_domain_irq(domain, irqofs + i * 32);
 				stat &= ~(1 << irqofs);
 			}
 		}

arch/arm/mach-omap1/irq.c

@@ -165,7 +165,7 @@ asmlinkage void __exception_irq_entry omap1_handle_irq(struct pt_regs *regs)
 		}
 irq:
 		if (irqnr)
-			handle_domain_irq(domain, irqnr, regs);
+			generic_handle_domain_irq(domain, irqnr);
 		else
 			break;
 	} while (irqnr);

arch/arm/mach-s3c/irq-s3c24xx.c

@@ -354,7 +354,7 @@ static inline int s3c24xx_handle_intc(struct s3c_irq_intc *intc,
 	if (!(pnd & (1 << offset)))
 		offset =  __ffs(pnd);
 
-	handle_domain_irq(intc->domain, intc_offset + offset, regs);
+	generic_handle_domain_irq(intc->domain, intc_offset + offset);
 	return true;
 }