ARM: remove old-style irq entry

The last user of arch_irq_handler_default is gone now, so the
entry-macro-multi.S file and all references to mach/entry-macro.S can
be removed, as well as the asm_do_IRQ() entrypoint into the interrupt
handling routines implemented in C.

Note: The ARMv7-M entry still uses its own top-level IRQ entry, calling
nvic_handle_irq() from assembly. This could be changed to go through
generic_handle_arch_irq() as well, but it's unclear to me if there are
any benefits.

Signed-off-by: Arnd Bergmann <[e-mail]>
[ardb: keep irq_handler macro as it carries all the IRQ stack handling]
Signed-off-by: Ard Biesheuvel <[e-mail]>
Tested-by: Marc Zyngier <[e-mail]>
Tested-by: Vladimir Murzin <[e-mail]> # ARMv7M
Reviewed-by: Linus Walleij <[e-mail]>

arch/arm/Kconfig

···
 	select GENERIC_CPU_AUTOPROBE
 	select GENERIC_EARLY_IOREMAP
 	select GENERIC_IDLE_POLL_SETUP
+	select GENERIC_IRQ_MULTI_HANDLER if MMU
 	select GENERIC_IRQ_PROBE
 	select GENERIC_IRQ_SHOW
 	select GENERIC_IRQ_SHOW_LEVEL
···
 	select AUTO_ZRELADDR
 	select TIMER_OF
 	select COMMON_CLK
-	select GENERIC_IRQ_MULTI_HANDLER
 	select HAVE_PCI
 	select PCI_DOMAINS_GENERIC if PCI
 	select SPARSE_IRQ
···
 	select ARM_AMBA
 	imply ARM_PATCH_PHYS_VIRT
 	select ARM_VIC
-	select GENERIC_IRQ_MULTI_HANDLER
 	select AUTO_ZRELADDR
 	select CLKSRC_MMIO
 	select CPU_ARM920T
···
 	select FOOTBRIDGE
 	select NEED_MACH_IO_H if !MMU
 	select NEED_MACH_MEMORY_H
-	select GENERIC_IRQ_MULTI_HANDLER
 	help
 	  Support for systems based on the DC21285 companion chip
 	  ("FootBridge"), such as the Simtec CATS and the Rebel NetWinder.
···
 	bool "IOP32x-based"
 	depends on MMU
 	select CPU_XSCALE
-	select GENERIC_IRQ_MULTI_HANDLER
 	select GPIO_IOP
 	select GPIOLIB
 	select FORCE_PCI
···
 	select ARCH_SUPPORTS_BIG_ENDIAN
 	select CPU_XSCALE
 	select DMABOUNCE if PCI
-	select GENERIC_IRQ_MULTI_HANDLER
 	select GPIO_IXP4XX
 	select GPIOLIB
 	select HAVE_PCI
···
 config ARCH_DOVE
 	bool "Marvell Dove"
 	select CPU_PJ4
-	select GENERIC_IRQ_MULTI_HANDLER
 	select GPIOLIB
 	select HAVE_PCI
 	select MVEBU_MBUS
···
 	select CLKSRC_MMIO
 	select TIMER_OF
 	select CPU_XSCALE if !CPU_XSC3
-	select GENERIC_IRQ_MULTI_HANDLER
 	select GPIO_PXA
 	select GPIOLIB
 	select IRQ_DOMAIN
···
 	select ARM_HAS_SG_CHAIN
 	select CPU_SA110
 	select FIQ
-	select GENERIC_IRQ_MULTI_HANDLER
 	select HAVE_PATA_PLATFORM
 	select ISA_DMA_API
 	select LEGACY_TIMER_TICK
···
 	select COMMON_CLK
 	select CPU_FREQ
 	select CPU_SA1100
-	select GENERIC_IRQ_MULTI_HANDLER
 	select GPIOLIB
 	select IRQ_DOMAIN
 	select ISA
···
 	select CLKSRC_SAMSUNG_PWM
 	select GPIO_SAMSUNG
 	select GPIOLIB
-	select GENERIC_IRQ_MULTI_HANDLER
 	select HAVE_S3C2410_I2C if I2C
 	select NEED_MACH_IO_H
 	select S3C2410_WATCHDOG
···
 	select ARCH_OMAP
 	select CLKSRC_MMIO
 	select GENERIC_IRQ_CHIP
-	select GENERIC_IRQ_MULTI_HANDLER
 	select GPIOLIB
 	select HAVE_LEGACY_CLK
 	select IRQ_DOMAIN
···
 
 config IRQSTACKS
 	def_bool y
-	depends on GENERIC_IRQ_MULTI_HANDLER && THREAD_INFO_IN_TASK
+	depends on THREAD_INFO_IN_TASK
 	select HAVE_IRQ_EXIT_ON_IRQ_STACK
 	select HAVE_SOFTIRQ_ON_OWN_STACK
 

arch/arm/include/asm/entry-macro-multi.S

···
-/* SPDX-License-Identifier: GPL-2.0 */
-#include <asm/assembler.h>
-
-/*
- * Interrupt handling.  Preserves r7, r8, r9
- */
-	.macro	arch_irq_handler_default
-	get_irqnr_preamble r6, lr
-1:	get_irqnr_and_base r0, r2, r6, lr
-	movne	r1, sp
-	@
-	@ routine called with r0 = irq number, r1 = struct pt_regs *
-	@
-	badrne	lr, 1b
-	bne	asm_do_IRQ
-	.endm

arch/arm/include/asm/irq.h

···
 struct irqaction;
 struct pt_regs;
 
-extern void asm_do_IRQ(unsigned int, struct pt_regs *);
 void handle_IRQ(unsigned int, struct pt_regs *);
 void init_IRQ(void);
 

arch/arm/include/asm/mach/arch.h

···
 	void			(*init_time)(void);
 	void			(*init_machine)(void);
 	void			(*init_late)(void);
-#ifdef CONFIG_GENERIC_IRQ_MULTI_HANDLER
 	void			(*handle_irq)(struct pt_regs *);
-#endif
 	void			(*restart)(enum reboot_mode, const char *);
 };
 

arch/arm/kernel/entry-armv.S

···
 #include <asm/glue-df.h>
 #include <asm/glue-pf.h>
 #include <asm/vfpmacros.h>
-#ifndef CONFIG_GENERIC_IRQ_MULTI_HANDLER
-#include <mach/entry-macro.S>
-#endif
 #include <asm/thread_notify.h>
 #include <asm/unwind.h>
 #include <asm/unistd.h>
···
 #include <asm/uaccess-asm.h>
 
 #include "entry-header.S"
-#include <asm/entry-macro-multi.S>
 #include <asm/probes.h>
 
 /*
  * Interrupt handling.
  */
 	.macro	irq_handler, from_user:req
-#ifdef CONFIG_GENERIC_IRQ_MULTI_HANDLER
 	mov	r0, sp
 #ifdef CONFIG_IRQSTACKS
 	mov_l	r2, irq_stack_ptr	@ Take base address
···
 	mov	sp, r9			@ Restore original SP
 #endif // CONFIG_UNWINDER_ARM
 #endif // CONFIG_IRQSTACKS
-#else
-	arch_irq_handler_default
-#endif
 	.endm
 
 	.macro	pabt_helper

arch/arm/kernel/irq.c

···
 		ack_bad_irq(irq);
 }
 
-/*
- * asm_do_IRQ is the interface to be used from assembly code.
- */
-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)
 {
 	int ret;