Merge remote-tracking branch 'arm64/for-next/fiq'

The FIQ support series, already merged into arm64, is a dependency
of the M1 bring-up series and was split off after the first few
versions.

Signed-off-by: Hector Martin <[e-mail]>

arch/arm64/Kconfig

···
 	select GENERIC_EARLY_IOREMAP
 	select GENERIC_IDLE_POLL_SETUP
 	select GENERIC_IRQ_IPI
-	select GENERIC_IRQ_MULTI_HANDLER
 	select GENERIC_IRQ_PROBE
 	select GENERIC_IRQ_SHOW
 	select GENERIC_IRQ_SHOW_LEVEL

arch/arm64/include/asm/arch_gicv3.h

···
 
 static inline void gic_arch_enable_irqs(void)
 {
-	asm volatile ("msr daifclr, #2" : : : "memory");
+	asm volatile ("msr daifclr, #3" : : : "memory");
 }
 
 #endif /* __ASSEMBLY__ */

arch/arm64/include/asm/assembler.h

···
 	msr	daif, \flags
 	.endm
 
-	/* IRQ is the lowest priority flag, unconditionally unmask the rest. */
-	.macro enable_da_f
-	msr	daifclr, #(8 | 4 | 1)
+	/* IRQ/FIQ are the lowest priority flags, unconditionally unmask the rest. */
+	.macro enable_da
+	msr	daifclr, #(8 | 4)
 	.endm
 
 /*
···
  */
 	.macro	save_and_disable_irq, flags
 	mrs	\flags, daif
-	msr	daifset, #2
+	msr	daifset, #3
 	.endm
 
 	.macro	restore_irq, flags

arch/arm64/include/asm/daifflags.h

···
 #include <asm/ptrace.h>
 
 #define DAIF_PROCCTX		0
-#define DAIF_PROCCTX_NOIRQ	PSR_I_BIT
-#define DAIF_ERRCTX		(PSR_I_BIT | PSR_A_BIT)
+#define DAIF_PROCCTX_NOIRQ	(PSR_I_BIT | PSR_F_BIT)
+#define DAIF_ERRCTX		(PSR_A_BIT | PSR_I_BIT | PSR_F_BIT)
 #define DAIF_MASK		(PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT)
 
 
···
 	if (system_uses_irq_prio_masking()) {
 		/* If IRQs are masked with PMR, reflect it in the flags */
 		if (read_sysreg_s(SYS_ICC_PMR_EL1) != GIC_PRIO_IRQON)
-			flags |= PSR_I_BIT;
+			flags |= PSR_I_BIT | PSR_F_BIT;
 	}
 
 	return flags;
···
 	bool irq_disabled = flags & PSR_I_BIT;
 
 	WARN_ON(system_has_prio_mask_debugging() &&
-		!(read_sysreg(daif) & PSR_I_BIT));
+		(read_sysreg(daif) & (PSR_I_BIT | PSR_F_BIT)) != (PSR_I_BIT | PSR_F_BIT));
 
 	if (!irq_disabled) {
 		trace_hardirqs_on();
···
 			 * If interrupts are disabled but we can take
 			 * asynchronous errors, we can take NMIs
 			 */
-			flags &= ~PSR_I_BIT;
+			flags &= ~(PSR_I_BIT | PSR_F_BIT);
 			pmr = GIC_PRIO_IRQOFF;
 		} else {
 			pmr = GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET;

arch/arm64/include/asm/irq.h

···
 
 struct pt_regs;
 
+int set_handle_irq(void (*handle_irq)(struct pt_regs *));
+#define set_handle_irq	set_handle_irq
+int set_handle_fiq(void (*handle_fiq)(struct pt_regs *));
+
 static inline int nr_legacy_irqs(void)
 {
 	return 0;

arch/arm64/include/asm/irqflags.h

···
 
 /*
  * Aarch64 has flags for masking: Debug, Asynchronous (serror), Interrupts and
- * FIQ exceptions, in the 'daif' register. We mask and unmask them in 'dai'
+ * FIQ exceptions, in the 'daif' register. We mask and unmask them in 'daif'
  * order:
  * Masking debug exceptions causes all other exceptions to be masked too/
- * Masking SError masks irq, but not debug exceptions. Masking irqs has no
- * side effects for other flags. Keeping to this order makes it easier for
- * entry.S to know which exceptions should be unmasked.
- *
- * FIQ is never expected, but we mask it when we disable debug exceptions, and
- * unmask it at all other times.
+ * Masking SError masks IRQ/FIQ, but not debug exceptions. IRQ and FIQ are
+ * always masked and unmasked together, and have no side effects for other
+ * flags. Keeping to this order makes it easier for entry.S to know which
+ * exceptions should be unmasked.
  */
 
 /*
···
 	}
 
 	asm volatile(ALTERNATIVE(
-		"msr	daifclr, #2		// arch_local_irq_enable",
+		"msr	daifclr, #3		// arch_local_irq_enable",
 		__msr_s(SYS_ICC_PMR_EL1, "%0"),
 		ARM64_HAS_IRQ_PRIO_MASKING)
 		:
···
 	}
 
 	asm volatile(ALTERNATIVE(
-		"msr	daifset, #2		// arch_local_irq_disable",
+		"msr	daifset, #3		// arch_local_irq_disable",
 		__msr_s(SYS_ICC_PMR_EL1, "%0"),
 		ARM64_HAS_IRQ_PRIO_MASKING)
 		:

arch/arm64/kernel/entry.S

···
 /*
  * Interrupt handling.
  */
-	.macro	irq_handler
-	ldr_l	x1, handle_arch_irq
+	.macro	irq_handler, handler:req
+	ldr_l	x1, \handler
 	mov	x0, sp
 	irq_stack_entry
 	blr	x1
···
 #endif
 	.endm
 
+	.macro el1_interrupt_handler, handler:req
+	gic_prio_irq_setup pmr=x20, tmp=x1
+	enable_da
+
+	mov	x0, sp
+	bl	enter_el1_irq_or_nmi
+
+	irq_handler	\handler
+
+#ifdef CONFIG_PREEMPTION
+	ldr	x24, [tsk, #TSK_TI_PREEMPT]	// get preempt count
+alternative_if ARM64_HAS_IRQ_PRIO_MASKING
+	/*
+	 * DA were cleared at start of handling, and IF are cleared by
+	 * the GIC irqchip driver using gic_arch_enable_irqs() for
+	 * normal IRQs. If anything is set, it means we come back from
+	 * an NMI instead of a normal IRQ, so skip preemption
+	 */
+	mrs	x0, daif
+	orr	x24, x24, x0
+alternative_else_nop_endif
+	cbnz	x24, 1f				// preempt count != 0 || NMI return path
+	bl	arm64_preempt_schedule_irq	// irq en/disable is done inside
+1:
+#endif
+
+	mov	x0, sp
+	bl	exit_el1_irq_or_nmi
+	.endm
+
+	.macro el0_interrupt_handler, handler:req
+	gic_prio_irq_setup pmr=x20, tmp=x0
+	user_exit_irqoff
+	enable_da
+
+	tbz	x22, #55, 1f
+	bl	do_el0_irq_bp_hardening
+1:
+	irq_handler	\handler
+	.endm
+
 	.text
 
 /*
···
 
 	kernel_ventry	1, sync				// Synchronous EL1h
 	kernel_ventry	1, irq				// IRQ EL1h
-	kernel_ventry	1, fiq_invalid			// FIQ EL1h
+	kernel_ventry	1, fiq				// FIQ EL1h
 	kernel_ventry	1, error			// Error EL1h
 
 	kernel_ventry	0, sync				// Synchronous 64-bit EL0
 	kernel_ventry	0, irq				// IRQ 64-bit EL0
-	kernel_ventry	0, fiq_invalid			// FIQ 64-bit EL0
+	kernel_ventry	0, fiq				// FIQ 64-bit EL0
 	kernel_ventry	0, error			// Error 64-bit EL0
 
 #ifdef CONFIG_COMPAT
 	kernel_ventry	0, sync_compat, 32		// Synchronous 32-bit EL0
 	kernel_ventry	0, irq_compat, 32		// IRQ 32-bit EL0
-	kernel_ventry	0, fiq_invalid_compat, 32	// FIQ 32-bit EL0
+	kernel_ventry	0, fiq_compat, 32		// FIQ 32-bit EL0
 	kernel_ventry	0, error_compat, 32		// Error 32-bit EL0
 #else
 	kernel_ventry	0, sync_invalid, 32		// Synchronous 32-bit EL0
···
 	inv_entry 0, BAD_ERROR
 SYM_CODE_END(el0_error_invalid)
 
-#ifdef CONFIG_COMPAT
-SYM_CODE_START_LOCAL(el0_fiq_invalid_compat)
-	inv_entry 0, BAD_FIQ, 32
-SYM_CODE_END(el0_fiq_invalid_compat)
-#endif
-
 SYM_CODE_START_LOCAL(el1_sync_invalid)
 	inv_entry 1, BAD_SYNC
 SYM_CODE_END(el1_sync_invalid)
···
 	.align	6
 SYM_CODE_START_LOCAL_NOALIGN(el1_irq)
 	kernel_entry 1
-	gic_prio_irq_setup pmr=x20, tmp=x1
-	enable_da_f
-
-	mov	x0, sp
-	bl	enter_el1_irq_or_nmi
-
-	irq_handler
-
-#ifdef CONFIG_PREEMPTION
-	ldr	x24, [tsk, #TSK_TI_PREEMPT]	// get preempt count
-alternative_if ARM64_HAS_IRQ_PRIO_MASKING
-	/*
-	 * DA_F were cleared at start of handling. If anything is set in DAIF,
-	 * we come back from an NMI, so skip preemption
-	 */
-	mrs	x0, daif
-	orr	x24, x24, x0
-alternative_else_nop_endif
-	cbnz	x24, 1f				// preempt count != 0 || NMI return path
-	bl	arm64_preempt_schedule_irq	// irq en/disable is done inside
-1:
-#endif
-
-	mov	x0, sp
-	bl	exit_el1_irq_or_nmi
-
+	el1_interrupt_handler handle_arch_irq
 	kernel_exit 1
 SYM_CODE_END(el1_irq)
+
+SYM_CODE_START_LOCAL_NOALIGN(el1_fiq)
+	kernel_entry 1
+	el1_interrupt_handler handle_arch_fiq
+	kernel_exit 1
+SYM_CODE_END(el1_fiq)
 
 /*
  * EL0 mode handlers.
···
 	b	el0_irq_naked
 SYM_CODE_END(el0_irq_compat)
 
+SYM_CODE_START_LOCAL_NOALIGN(el0_fiq_compat)
+	kernel_entry 0, 32
+	b	el0_fiq_naked
+SYM_CODE_END(el0_fiq_compat)
+
 SYM_CODE_START_LOCAL_NOALIGN(el0_error_compat)
 	kernel_entry 0, 32
 	b	el0_error_naked
···
 SYM_CODE_START_LOCAL_NOALIGN(el0_irq)
 	kernel_entry 0
 el0_irq_naked:
-	gic_prio_irq_setup pmr=x20, tmp=x0
-	user_exit_irqoff
-	enable_da_f
-
-	tbz	x22, #55, 1f
-	bl	do_el0_irq_bp_hardening
-1:
-	irq_handler
-
+	el0_interrupt_handler handle_arch_irq
 	b	ret_to_user
 SYM_CODE_END(el0_irq)
+
+SYM_CODE_START_LOCAL_NOALIGN(el0_fiq)
+	kernel_entry 0
+el0_fiq_naked:
+	el0_interrupt_handler handle_arch_fiq
+	b	ret_to_user
+SYM_CODE_END(el0_fiq)
 
 SYM_CODE_START_LOCAL(el1_error)
 	kernel_entry 1
···
 	mov	x0, sp
 	mov	x1, x25
 	bl	do_serror
-	enable_da_f
+	enable_da
 	b	ret_to_user
 SYM_CODE_END(el0_error)
 

arch/arm64/kernel/irq.c

···
 }
 #endif
 
+static void default_handle_irq(struct pt_regs *regs)
+{
+	panic("IRQ taken without a root IRQ handler\n");
+}
+
+static void default_handle_fiq(struct pt_regs *regs)
+{
+	panic("FIQ taken without a root FIQ handler\n");
+}
+
+void (*handle_arch_irq)(struct pt_regs *) __ro_after_init = default_handle_irq;
+void (*handle_arch_fiq)(struct pt_regs *) __ro_after_init = default_handle_fiq;
+
+int __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
+{
+	if (handle_arch_irq != default_handle_irq)
+		return -EBUSY;
+
+	handle_arch_irq = handle_irq;
+	pr_info("Root IRQ handler: %ps\n", handle_irq);
+	return 0;
+}
+
+int __init set_handle_fiq(void (*handle_fiq)(struct pt_regs *))
+{
+	if (handle_arch_fiq != default_handle_fiq)
+		return -EBUSY;
+
+	handle_arch_fiq = handle_fiq;
+	pr_info("Root FIQ handler: %ps\n", handle_fiq);
+	return 0;
+}
+
 void __init init_IRQ(void)
 {
 	init_irq_stacks();
 	init_irq_scs();
 	irqchip_init();
-	if (!handle_arch_irq)
-		panic("No interrupt controller found.");
 
 	if (system_uses_irq_prio_masking()) {
 		/*

arch/arm64/kernel/process.c

···
 	unsigned long daif_bits;
 
 	daif_bits = read_sysreg(daif);
-	write_sysreg(daif_bits | PSR_I_BIT, daif);
+	write_sysreg(daif_bits | PSR_I_BIT | PSR_F_BIT, daif);
 
 	/*
 	 * Unmask PMR before going idle to make sure interrupts can

arch/arm64/kernel/smp.c

···
 	cpuflags = read_sysreg(daif);
 
 	WARN_ON(!(cpuflags & PSR_I_BIT));
+	WARN_ON(!(cpuflags & PSR_F_BIT));
 
 	gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET);
 }

include/linux/irq.h

···
  */
 extern void (*handle_arch_irq)(struct pt_regs *) __ro_after_init;
 #else
+#ifndef set_handle_irq
 #define set_handle_irq(handle_irq)		\
 	do {					\
 		(void)handle_irq;		\
 		WARN_ON(1);			\
 	} while (0)
+#endif
 #endif
 
 #endif /* _LINUX_IRQ_H */