sched_ext: Maintain an online cid mask in the scheduler arenagrafted

Schedulers on the default cid mapping treat [0, nr_online_cids) as the
online set and restart on hotplug. Schedulers that install their own mapping
with scx_bpf_cid_override() have no way to learn which cids are online: the
count no longer identifies members and the CPU-form cpumask is unusable from
cid programs. This is an obvious hole in the cid API.

Add scx_bpf_online_cmask(), a kernel-maintained cmask in the scheduler's
arena, allocated alongside the per-CPU scratch masks and populated after the
cid mapping is finalized and before ops.init(), for child schedulers too.
The pointer stays valid through ops.exit() with no reference to take. It is
the arena offset as a void pointer, the same form struct_ops arena arguments
arrive in. The verifier types the void return as a scalar for the program's
arena cast.

The mask follows the SCX hotplug notifications: seeded from cpu_active_mask
and updated before ops.cid_online/offline() runs, so it lags cpu_online_mask
only inside a hotplug transition. Updates walk the scheduler list under the
lock that also serializes unlinking. Reads are live, not atomic snapshots.
Root initialization excludes hotplug.

v2: Reworded the getter kerneldoc (Andrea Righi).

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>

1 files changed, 774 insertions, 0 deletions

diff --git a/arch/mips/dec/setup.c b/arch/mips/dec/setup.c
new file mode 100644
index 000000000..78ad28ac1
--- /dev/null
+++ b/arch/mips/dec/setup.c
@@ -0,0 +1,774 @@
+/*
+ * System-specific setup, especially interrupts.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1998 Harald Koerfgen
+ * Copyright (C) 2000, 2001, 2002, 2003, 2005, 2020  Maciej W. Rozycki
+ */
+#include <linux/console.h>
+#include <linux/export.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/irq.h>
+#include <linux/irqnr.h>
+#include <linux/memblock.h>
+#include <linux/param.h>
+#include <linux/percpu-defs.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+#include <linux/pm.h>
+
+#include <asm/addrspace.h>
+#include <asm/bootinfo.h>
+#include <asm/cpu.h>
+#include <asm/cpu-features.h>
+#include <asm/cpu-type.h>
+#include <asm/irq.h>
+#include <asm/irq_cpu.h>
+#include <asm/mipsregs.h>
+#include <asm/page.h>
+#include <asm/reboot.h>
+#include <asm/sections.h>
+#include <asm/time.h>
+#include <asm/traps.h>
+#include <asm/wbflush.h>
+
+#include <asm/dec/interrupts.h>
+#include <asm/dec/ioasic.h>
+#include <asm/dec/ioasic_addrs.h>
+#include <asm/dec/ioasic_ints.h>
+#include <asm/dec/kn01.h>
+#include <asm/dec/kn02.h>
+#include <asm/dec/kn02ba.h>
+#include <asm/dec/kn02ca.h>
+#include <asm/dec/kn03.h>
+#include <asm/dec/kn230.h>
+#include <asm/dec/reset.h>
+#include <asm/dec/system.h>
+
+
+unsigned long dec_kn_slot_base, dec_kn_slot_size;
+
+EXPORT_SYMBOL(dec_kn_slot_base);
+EXPORT_SYMBOL(dec_kn_slot_size);
+
+int dec_tc_bus;
+
+DEFINE_SPINLOCK(ioasic_ssr_lock);
+EXPORT_SYMBOL(ioasic_ssr_lock);
+
+volatile u32 *ioasic_base;
+
+EXPORT_SYMBOL(ioasic_base);
+
+/*
+ * IRQ routing and priority tables.  Priorities are set as follows:
+ *
+ *		KN01	KN230	KN02	KN02-BA	KN02-CA	KN03
+ *
+ * MEMORY	CPU	CPU	CPU	ASIC	CPU	CPU
+ * RTC		CPU	CPU	CPU	ASIC	CPU	CPU
+ * DMA		-	-	-	ASIC	ASIC	ASIC
+ * SERIAL0	CPU	CPU	CSR	ASIC	ASIC	ASIC
+ * SERIAL1	-	-	-	ASIC	-	ASIC
+ * SCSI		CPU	CPU	CSR	ASIC	ASIC	ASIC
+ * ETHERNET	CPU	*	CSR	ASIC	ASIC	ASIC
+ * other	-	-	-	ASIC	-	-
+ * TC2		-	-	CSR	CPU	ASIC	ASIC
+ * TC1		-	-	CSR	CPU	ASIC	ASIC
+ * TC0		-	-	CSR	CPU	ASIC	ASIC
+ * other	-	CPU	-	CPU	ASIC	ASIC
+ * other	-	-	-	-	CPU	CPU
+ *
+ * * -- shared with SCSI
+ */
+
+int dec_interrupt[DEC_NR_INTS] = {
+	[0 ... DEC_NR_INTS - 1] = -1
+};
+
+EXPORT_SYMBOL(dec_interrupt);
+
+int_ptr cpu_mask_nr_tbl[DEC_MAX_CPU_INTS][2] = {
+	{ { .i = ~0 }, { .p = dec_intr_unimplemented } },
+};
+int_ptr asic_mask_nr_tbl[DEC_MAX_ASIC_INTS][2] = {
+	{ { .i = ~0 }, { .p = asic_intr_unimplemented } },
+};
+int cpu_fpu_mask = DEC_CPU_IRQ_MASK(DEC_CPU_INR_FPU);
+int *fpu_kstat_irq;
+
+static irq_handler_t busirq_handler;
+static unsigned int busirq_flags = IRQF_NO_THREAD;
+
+/*
+ * Bus error (DBE/IBE exceptions and bus interrupts) handling setup.
+ */
+static void __init dec_be_init(void)
+{
+	switch (mips_machtype) {
+	case MACH_DS23100:	/* DS2100/DS3100 Pmin/Pmax */
+		mips_set_be_handler(dec_kn01_be_handler);
+		busirq_handler = dec_kn01_be_interrupt;
+		busirq_flags |= IRQF_SHARED;
+		dec_kn01_be_init();
+		break;
+	case MACH_DS5000_1XX:	/* DS5000/1xx 3min */
+	case MACH_DS5000_XX:	/* DS5000/xx Maxine */
+		mips_set_be_handler(dec_kn02xa_be_handler);
+		busirq_handler = dec_kn02xa_be_interrupt;
+		dec_kn02xa_be_init();
+		break;
+	case MACH_DS5000_200:	/* DS5000/200 3max */
+	case MACH_DS5000_2X0:	/* DS5000/240 3max+ */
+	case MACH_DS5900:	/* DS5900 bigmax */
+		mips_set_be_handler(dec_ecc_be_handler);
+		busirq_handler = dec_ecc_be_interrupt;
+		dec_ecc_be_init();
+		break;
+	}
+}
+
+void __init plat_mem_setup(void)
+{
+	board_be_init = dec_be_init;
+
+	wbflush_setup();
+
+	_machine_restart = dec_machine_restart;
+	_machine_halt = dec_machine_halt;
+	pm_power_off = dec_machine_power_off;
+
+	ioport_resource.start = ~0UL;
+	ioport_resource.end = 0UL;
+
+	/* Stay away from the firmware working memory area for now. */
+	memblock_reserve(PHYS_OFFSET, __pa_symbol(&_text) - PHYS_OFFSET);
+}
+
+/*
+ * Machine-specific initialisation for KN01, aka DS2100 (aka Pmin)
+ * or DS3100 (aka Pmax).
+ */
+static int kn01_interrupt[DEC_NR_INTS] __initdata = {
+	[DEC_IRQ_CASCADE]	= -1,
+	[DEC_IRQ_AB_RECV]	= -1,
+	[DEC_IRQ_AB_XMIT]	= -1,
+	[DEC_IRQ_DZ11]		= DEC_CPU_IRQ_NR(KN01_CPU_INR_DZ11),
+	[DEC_IRQ_ASC]		= -1,
+	[DEC_IRQ_FLOPPY]	= -1,
+	[DEC_IRQ_FPU]		= DEC_CPU_IRQ_NR(DEC_CPU_INR_FPU),
+	[DEC_IRQ_HALT]		= -1,
+	[DEC_IRQ_ISDN]		= -1,
+	[DEC_IRQ_LANCE]		= DEC_CPU_IRQ_NR(KN01_CPU_INR_LANCE),
+	[DEC_IRQ_BUS]		= DEC_CPU_IRQ_NR(KN01_CPU_INR_BUS),
+	[DEC_IRQ_PSU]		= -1,
+	[DEC_IRQ_RTC]		= DEC_CPU_IRQ_NR(KN01_CPU_INR_RTC),
+	[DEC_IRQ_SCC0]		= -1,
+	[DEC_IRQ_SCC1]		= -1,
+	[DEC_IRQ_SII]		= DEC_CPU_IRQ_NR(KN01_CPU_INR_SII),
+	[DEC_IRQ_TC0]		= -1,
+	[DEC_IRQ_TC1]		= -1,
+	[DEC_IRQ_TC2]		= -1,
+	[DEC_IRQ_TIMER]		= -1,
+	[DEC_IRQ_VIDEO]		= DEC_CPU_IRQ_NR(KN01_CPU_INR_VIDEO),
+	[DEC_IRQ_ASC_MERR]	= -1,
+	[DEC_IRQ_ASC_ERR]	= -1,
+	[DEC_IRQ_ASC_DMA]	= -1,
+	[DEC_IRQ_FLOPPY_ERR]	= -1,
+	[DEC_IRQ_ISDN_ERR]	= -1,
+	[DEC_IRQ_ISDN_RXDMA]	= -1,
+	[DEC_IRQ_ISDN_TXDMA]	= -1,
+	[DEC_IRQ_LANCE_MERR]	= -1,
+	[DEC_IRQ_SCC0A_RXERR]	= -1,
+	[DEC_IRQ_SCC0A_RXDMA]	= -1,
+	[DEC_IRQ_SCC0A_TXERR]	= -1,
+	[DEC_IRQ_SCC0A_TXDMA]	= -1,
+	[DEC_IRQ_AB_RXERR]	= -1,
+	[DEC_IRQ_AB_RXDMA]	= -1,
+	[DEC_IRQ_AB_TXERR]	= -1,
+	[DEC_IRQ_AB_TXDMA]	= -1,
+	[DEC_IRQ_SCC1A_RXERR]	= -1,
+	[DEC_IRQ_SCC1A_RXDMA]	= -1,
+	[DEC_IRQ_SCC1A_TXERR]	= -1,
+	[DEC_IRQ_SCC1A_TXDMA]	= -1,
+};
+
+static int_ptr kn01_cpu_mask_nr_tbl[][2] __initdata = {
+	{ { .i = DEC_CPU_IRQ_MASK(KN01_CPU_INR_BUS) },
+		{ .i = DEC_CPU_IRQ_NR(KN01_CPU_INR_BUS) } },
+	{ { .i = DEC_CPU_IRQ_MASK(KN01_CPU_INR_RTC) },
+		{ .i = DEC_CPU_IRQ_NR(KN01_CPU_INR_RTC) } },
+	{ { .i = DEC_CPU_IRQ_MASK(KN01_CPU_INR_DZ11) },
+		{ .i = DEC_CPU_IRQ_NR(KN01_CPU_INR_DZ11) } },
+	{ { .i = DEC_CPU_IRQ_MASK(KN01_CPU_INR_SII) },
+		{ .i = DEC_CPU_IRQ_NR(KN01_CPU_INR_SII) } },
+	{ { .i = DEC_CPU_IRQ_MASK(KN01_CPU_INR_LANCE) },
+		{ .i = DEC_CPU_IRQ_NR(KN01_CPU_INR_LANCE) } },
+	{ { .i = DEC_CPU_IRQ_ALL },
+		{ .p = cpu_all_int } },
+};
+
+static void __init dec_init_kn01(void)
+{
+	/* IRQ routing. */
+	memcpy(&dec_interrupt, &kn01_interrupt,
+		sizeof(kn01_interrupt));
+
+	/* CPU IRQ priorities. */
+	memcpy(&cpu_mask_nr_tbl, &kn01_cpu_mask_nr_tbl,
+		sizeof(kn01_cpu_mask_nr_tbl));
+
+	mips_cpu_irq_init();
+
+}				/* dec_init_kn01 */
+
+
+/*
+ * Machine-specific initialisation for KN230, aka DS5100, aka MIPSmate.
+ */
+static int kn230_interrupt[DEC_NR_INTS] __initdata = {
+	[DEC_IRQ_CASCADE]	= -1,
+	[DEC_IRQ_AB_RECV]	= -1,
+	[DEC_IRQ_AB_XMIT]	= -1,
+	[DEC_IRQ_DZ11]		= DEC_CPU_IRQ_NR(KN230_CPU_INR_DZ11),
+	[DEC_IRQ_ASC]		= -1,
+	[DEC_IRQ_FLOPPY]	= -1,
+	[DEC_IRQ_FPU]		= DEC_CPU_IRQ_NR(DEC_CPU_INR_FPU),
+	[DEC_IRQ_HALT]		= DEC_CPU_IRQ_NR(KN230_CPU_INR_HALT),
+	[DEC_IRQ_ISDN]		= -1,
+	[DEC_IRQ_LANCE]		= DEC_CPU_IRQ_NR(KN230_CPU_INR_LANCE),
+	[DEC_IRQ_BUS]		= DEC_CPU_IRQ_NR(KN230_CPU_INR_BUS),
+	[DEC_IRQ_PSU]		= -1,
+	[DEC_IRQ_RTC]		= DEC_CPU_IRQ_NR(KN230_CPU_INR_RTC),
+	[DEC_IRQ_SCC0]		= -1,
+	[DEC_IRQ_SCC1]		= -1,
+	[DEC_IRQ_SII]		= DEC_CPU_IRQ_NR(KN230_CPU_INR_SII),
+	[DEC_IRQ_TC0]		= -1,
+	[DEC_IRQ_TC1]		= -1,
+	[DEC_IRQ_TC2]		= -1,
+	[DEC_IRQ_TIMER]		= -1,
+	[DEC_IRQ_VIDEO]		= -1,
+	[DEC_IRQ_ASC_MERR]	= -1,
+	[DEC_IRQ_ASC_ERR]	= -1,
+	[DEC_IRQ_ASC_DMA]	= -1,
+	[DEC_IRQ_FLOPPY_ERR]	= -1,
+	[DEC_IRQ_ISDN_ERR]	= -1,
+	[DEC_IRQ_ISDN_RXDMA]	= -1,
+	[DEC_IRQ_ISDN_TXDMA]	= -1,
+	[DEC_IRQ_LANCE_MERR]	= -1,
+	[DEC_IRQ_SCC0A_RXERR]	= -1,
+	[DEC_IRQ_SCC0A_RXDMA]	= -1,
+	[DEC_IRQ_SCC0A_TXERR]	= -1,
+	[DEC_IRQ_SCC0A_TXDMA]	= -1,
+	[DEC_IRQ_AB_RXERR]	= -1,
+	[DEC_IRQ_AB_RXDMA]	= -1,
+	[DEC_IRQ_AB_TXERR]	= -1,
+	[DEC_IRQ_AB_TXDMA]	= -1,
+	[DEC_IRQ_SCC1A_RXERR]	= -1,
+	[DEC_IRQ_SCC1A_RXDMA]	= -1,
+	[DEC_IRQ_SCC1A_TXERR]	= -1,
+	[DEC_IRQ_SCC1A_TXDMA]	= -1,
+};
+
+static int_ptr kn230_cpu_mask_nr_tbl[][2] __initdata = {
+	{ { .i = DEC_CPU_IRQ_MASK(KN230_CPU_INR_BUS) },
+		{ .i = DEC_CPU_IRQ_NR(KN230_CPU_INR_BUS) } },
+	{ { .i = DEC_CPU_IRQ_MASK(KN230_CPU_INR_RTC) },
+		{ .i = DEC_CPU_IRQ_NR(KN230_CPU_INR_RTC) } },
+	{ { .i = DEC_CPU_IRQ_MASK(KN230_CPU_INR_DZ11) },
+		{ .i = DEC_CPU_IRQ_NR(KN230_CPU_INR_DZ11) } },
+	{ { .i = DEC_CPU_IRQ_MASK(KN230_CPU_INR_SII) },
+		{ .i = DEC_CPU_IRQ_NR(KN230_CPU_INR_SII) } },
+	{ { .i = DEC_CPU_IRQ_ALL },
+		{ .p = cpu_all_int } },
+};
+
+static void __init dec_init_kn230(void)
+{
+	/* IRQ routing. */
+	memcpy(&dec_interrupt, &kn230_interrupt,
+		sizeof(kn230_interrupt));
+
+	/* CPU IRQ priorities. */
+	memcpy(&cpu_mask_nr_tbl, &kn230_cpu_mask_nr_tbl,
+		sizeof(kn230_cpu_mask_nr_tbl));
+
+	mips_cpu_irq_init();
+
+}				/* dec_init_kn230 */
+
+
+/*
+ * Machine-specific initialisation for KN02, aka DS5000/200, aka 3max.
+ */
+static int kn02_interrupt[DEC_NR_INTS] __initdata = {
+	[DEC_IRQ_CASCADE]	= DEC_CPU_IRQ_NR(KN02_CPU_INR_CASCADE),
+	[DEC_IRQ_AB_RECV]	= -1,
+	[DEC_IRQ_AB_XMIT]	= -1,
+	[DEC_IRQ_DZ11]		= KN02_IRQ_NR(KN02_CSR_INR_DZ11),
+	[DEC_IRQ_ASC]		= KN02_IRQ_NR(KN02_CSR_INR_ASC),
+	[DEC_IRQ_FLOPPY]	= -1,
+	[DEC_IRQ_FPU]		= DEC_CPU_IRQ_NR(DEC_CPU_INR_FPU),
+	[DEC_IRQ_HALT]		= -1,
+	[DEC_IRQ_ISDN]		= -1,
+	[DEC_IRQ_LANCE]		= KN02_IRQ_NR(KN02_CSR_INR_LANCE),
+	[DEC_IRQ_BUS]		= DEC_CPU_IRQ_NR(KN02_CPU_INR_BUS),
+	[DEC_IRQ_PSU]		= -1,
+	[DEC_IRQ_RTC]		= DEC_CPU_IRQ_NR(KN02_CPU_INR_RTC),
+	[DEC_IRQ_SCC0]		= -1,
+	[DEC_IRQ_SCC1]		= -1,
+	[DEC_IRQ_SII]		= -1,
+	[DEC_IRQ_TC0]		= KN02_IRQ_NR(KN02_CSR_INR_TC0),
+	[DEC_IRQ_TC1]		= KN02_IRQ_NR(KN02_CSR_INR_TC1),
+	[DEC_IRQ_TC2]		= KN02_IRQ_NR(KN02_CSR_INR_TC2),
+	[DEC_IRQ_TIMER]		= -1,
+	[DEC_IRQ_VIDEO]		= -1,
+	[DEC_IRQ_ASC_MERR]	= -1,
+	[DEC_IRQ_ASC_ERR]	= -1,
+	[DEC_IRQ_ASC_DMA]	= -1,
+	[DEC_IRQ_FLOPPY_ERR]	= -1,
+	[DEC_IRQ_ISDN_ERR]	= -1,
+	[DEC_IRQ_ISDN_RXDMA]	= -1,
+	[DEC_IRQ_ISDN_TXDMA]	= -1,
+	[DEC_IRQ_LANCE_MERR]	= -1,
+	[DEC_IRQ_SCC0A_RXERR]	= -1,
+	[DEC_IRQ_SCC0A_RXDMA]	= -1,
+	[DEC_IRQ_SCC0A_TXERR]	= -1,
+	[DEC_IRQ_SCC0A_TXDMA]	= -1,
+	[DEC_IRQ_AB_RXERR]	= -1,
+	[DEC_IRQ_AB_RXDMA]	= -1,
+	[DEC_IRQ_AB_TXERR]	= -1,
+	[DEC_IRQ_AB_TXDMA]	= -1,
+	[DEC_IRQ_SCC1A_RXERR]	= -1,
+	[DEC_IRQ_SCC1A_RXDMA]	= -1,
+	[DEC_IRQ_SCC1A_TXERR]	= -1,
+	[DEC_IRQ_SCC1A_TXDMA]	= -1,
+};
+
+static int_ptr kn02_cpu_mask_nr_tbl[][2] __initdata = {
+	{ { .i = DEC_CPU_IRQ_MASK(KN02_CPU_INR_BUS) },
+		{ .i = DEC_CPU_IRQ_NR(KN02_CPU_INR_BUS) } },
+	{ { .i = DEC_CPU_IRQ_MASK(KN02_CPU_INR_RTC) },
+		{ .i = DEC_CPU_IRQ_NR(KN02_CPU_INR_RTC) } },
+	{ { .i = DEC_CPU_IRQ_MASK(KN02_CPU_INR_CASCADE) },
+		{ .p = kn02_io_int } },
+	{ { .i = DEC_CPU_IRQ_ALL },
+		{ .p = cpu_all_int } },
+};
+
+static int_ptr kn02_asic_mask_nr_tbl[][2] __initdata = {
+	{ { .i = KN02_IRQ_MASK(KN02_CSR_INR_DZ11) },
+		{ .i = KN02_IRQ_NR(KN02_CSR_INR_DZ11) } },
+	{ { .i = KN02_IRQ_MASK(KN02_CSR_INR_ASC) },
+		{ .i = KN02_IRQ_NR(KN02_CSR_INR_ASC) } },
+	{ { .i = KN02_IRQ_MASK(KN02_CSR_INR_LANCE) },
+		{ .i = KN02_IRQ_NR(KN02_CSR_INR_LANCE) } },
+	{ { .i = KN02_IRQ_MASK(KN02_CSR_INR_TC2) },
+		{ .i = KN02_IRQ_NR(KN02_CSR_INR_TC2) } },
+	{ { .i = KN02_IRQ_MASK(KN02_CSR_INR_TC1) },
+		{ .i = KN02_IRQ_NR(KN02_CSR_INR_TC1) } },
+	{ { .i = KN02_IRQ_MASK(KN02_CSR_INR_TC0) },
+		{ .i = KN02_IRQ_NR(KN02_CSR_INR_TC0) } },
+	{ { .i = KN02_IRQ_ALL },
+		{ .p = kn02_all_int } },
+};
+
+static void __init dec_init_kn02(void)
+{
+	/* IRQ routing. */
+	memcpy(&dec_interrupt, &kn02_interrupt,
+		sizeof(kn02_interrupt));
+
+	/* CPU IRQ priorities. */
+	memcpy(&cpu_mask_nr_tbl, &kn02_cpu_mask_nr_tbl,
+		sizeof(kn02_cpu_mask_nr_tbl));
+
+	/* KN02 CSR IRQ priorities. */
+	memcpy(&asic_mask_nr_tbl, &kn02_asic_mask_nr_tbl,
+		sizeof(kn02_asic_mask_nr_tbl));
+
+	mips_cpu_irq_init();
+	init_kn02_irqs(KN02_IRQ_BASE);
+
+}				/* dec_init_kn02 */
+
+
+/*
+ * Machine-specific initialisation for KN02-BA, aka DS5000/1xx
+ * (xx = 20, 25, 33), aka 3min.  Also applies to KN04(-BA), aka
+ * DS5000/150, aka 4min.
+ */
+static int kn02ba_interrupt[DEC_NR_INTS] __initdata = {
+	[DEC_IRQ_CASCADE]	= DEC_CPU_IRQ_NR(KN02BA_CPU_INR_CASCADE),
+	[DEC_IRQ_AB_RECV]	= -1,
+	[DEC_IRQ_AB_XMIT]	= -1,
+	[DEC_IRQ_DZ11]		= -1,
+	[DEC_IRQ_ASC]		= IO_IRQ_NR(KN02BA_IO_INR_ASC),
+	[DEC_IRQ_FLOPPY]	= -1,
+	[DEC_IRQ_FPU]		= DEC_CPU_IRQ_NR(DEC_CPU_INR_FPU),
+	[DEC_IRQ_HALT]		= DEC_CPU_IRQ_NR(KN02BA_CPU_INR_HALT),
+	[DEC_IRQ_ISDN]		= -1,
+	[DEC_IRQ_LANCE]		= IO_IRQ_NR(KN02BA_IO_INR_LANCE),
+	[DEC_IRQ_BUS]		= IO_IRQ_NR(KN02BA_IO_INR_BUS),
+	[DEC_IRQ_PSU]		= IO_IRQ_NR(KN02BA_IO_INR_PSU),
+	[DEC_IRQ_RTC]		= IO_IRQ_NR(KN02BA_IO_INR_RTC),
+	[DEC_IRQ_SCC0]		= IO_IRQ_NR(KN02BA_IO_INR_SCC0),
+	[DEC_IRQ_SCC1]		= IO_IRQ_NR(KN02BA_IO_INR_SCC1),
+	[DEC_IRQ_SII]		= -1,
+	[DEC_IRQ_TC0]		= DEC_CPU_IRQ_NR(KN02BA_CPU_INR_TC0),
+	[DEC_IRQ_TC1]		= DEC_CPU_IRQ_NR(KN02BA_CPU_INR_TC1),
+	[DEC_IRQ_TC2]		= DEC_CPU_IRQ_NR(KN02BA_CPU_INR_TC2),
+	[DEC_IRQ_TIMER]		= -1,
+	[DEC_IRQ_VIDEO]		= -1,
+	[DEC_IRQ_ASC_MERR]	= IO_IRQ_NR(IO_INR_ASC_MERR),
+	[DEC_IRQ_ASC_ERR]	= IO_IRQ_NR(IO_INR_ASC_ERR),
+	[DEC_IRQ_ASC_DMA]	= IO_IRQ_NR(IO_INR_ASC_DMA),
+	[DEC_IRQ_FLOPPY_ERR]	= -1,
+	[DEC_IRQ_ISDN_ERR]	= -1,
+	[DEC_IRQ_ISDN_RXDMA]	= -1,
+	[DEC_IRQ_ISDN_TXDMA]	= -1,
+	[DEC_IRQ_LANCE_MERR]	= IO_IRQ_NR(IO_INR_LANCE_MERR),
+	[DEC_IRQ_SCC0A_RXERR]	= IO_IRQ_NR(IO_INR_SCC0A_RXERR),
+	[DEC_IRQ_SCC0A_RXDMA]	= IO_IRQ_NR(IO_INR_SCC0A_RXDMA),
+	[DEC_IRQ_SCC0A_TXERR]	= IO_IRQ_NR(IO_INR_SCC0A_TXERR),
+	[DEC_IRQ_SCC0A_TXDMA]	= IO_IRQ_NR(IO_INR_SCC0A_TXDMA),
+	[DEC_IRQ_AB_RXERR]	= -1,
+	[DEC_IRQ_AB_RXDMA]	= -1,
+	[DEC_IRQ_AB_TXERR]	= -1,
+	[DEC_IRQ_AB_TXDMA]	= -1,
+	[DEC_IRQ_SCC1A_RXERR]	= IO_IRQ_NR(IO_INR_SCC1A_RXERR),
+	[DEC_IRQ_SCC1A_RXDMA]	= IO_IRQ_NR(IO_INR_SCC1A_RXDMA),
+	[DEC_IRQ_SCC1A_TXERR]	= IO_IRQ_NR(IO_INR_SCC1A_TXERR),
+	[DEC_IRQ_SCC1A_TXDMA]	= IO_IRQ_NR(IO_INR_SCC1A_TXDMA),
+};
+
+static int_ptr kn02ba_cpu_mask_nr_tbl[][2] __initdata = {
+	{ { .i = DEC_CPU_IRQ_MASK(KN02BA_CPU_INR_CASCADE) },
+		{ .p = kn02xa_io_int } },
+	{ { .i = DEC_CPU_IRQ_MASK(KN02BA_CPU_INR_TC2) },
+		{ .i = DEC_CPU_IRQ_NR(KN02BA_CPU_INR_TC2) } },
+	{ { .i = DEC_CPU_IRQ_MASK(KN02BA_CPU_INR_TC1) },
+		{ .i = DEC_CPU_IRQ_NR(KN02BA_CPU_INR_TC1) } },
+	{ { .i = DEC_CPU_IRQ_MASK(KN02BA_CPU_INR_TC0) },
+		{ .i = DEC_CPU_IRQ_NR(KN02BA_CPU_INR_TC0) } },
+	{ { .i = DEC_CPU_IRQ_ALL },
+		{ .p = cpu_all_int } },
+};
+
+static int_ptr kn02ba_asic_mask_nr_tbl[][2] __initdata = {
+	{ { .i = IO_IRQ_MASK(KN02BA_IO_INR_BUS) },
+		{ .i = IO_IRQ_NR(KN02BA_IO_INR_BUS) } },
+	{ { .i = IO_IRQ_MASK(KN02BA_IO_INR_RTC) },
+		{ .i = IO_IRQ_NR(KN02BA_IO_INR_RTC) } },
+	{ { .i = IO_IRQ_DMA },
+		{ .p = asic_dma_int } },
+	{ { .i = IO_IRQ_MASK(KN02BA_IO_INR_SCC0) },
+		{ .i = IO_IRQ_NR(KN02BA_IO_INR_SCC0) } },
+	{ { .i = IO_IRQ_MASK(KN02BA_IO_INR_SCC1) },
+		{ .i = IO_IRQ_NR(KN02BA_IO_INR_SCC1) } },
+	{ { .i = IO_IRQ_MASK(KN02BA_IO_INR_ASC) },
+		{ .i = IO_IRQ_NR(KN02BA_IO_INR_ASC) } },
+	{ { .i = IO_IRQ_MASK(KN02BA_IO_INR_LANCE) },
+		{ .i = IO_IRQ_NR(KN02BA_IO_INR_LANCE) } },
+	{ { .i = IO_IRQ_ALL },
+		{ .p = asic_all_int } },
+};
+
+static void __init dec_init_kn02ba(void)
+{
+	/* IRQ routing. */
+	memcpy(&dec_interrupt, &kn02ba_interrupt,
+		sizeof(kn02ba_interrupt));
+
+	/* CPU IRQ priorities. */
+	memcpy(&cpu_mask_nr_tbl, &kn02ba_cpu_mask_nr_tbl,
+		sizeof(kn02ba_cpu_mask_nr_tbl));
+
+	/* I/O ASIC IRQ priorities. */
+	memcpy(&asic_mask_nr_tbl, &kn02ba_asic_mask_nr_tbl,
+		sizeof(kn02ba_asic_mask_nr_tbl));
+
+	mips_cpu_irq_init();
+	init_ioasic_irqs(IO_IRQ_BASE);
+
+}				/* dec_init_kn02ba */
+
+
+/*
+ * Machine-specific initialisation for KN02-CA, aka DS5000/xx,
+ * (xx = 20, 25, 33), aka MAXine.  Also applies to KN04(-CA), aka
+ * DS5000/50, aka 4MAXine.
+ */
+static int kn02ca_interrupt[DEC_NR_INTS] __initdata = {
+	[DEC_IRQ_CASCADE]	= DEC_CPU_IRQ_NR(KN02CA_CPU_INR_CASCADE),
+	[DEC_IRQ_AB_RECV]	= IO_IRQ_NR(KN02CA_IO_INR_AB_RECV),
+	[DEC_IRQ_AB_XMIT]	= IO_IRQ_NR(KN02CA_IO_INR_AB_XMIT),
+	[DEC_IRQ_DZ11]		= -1,
+	[DEC_IRQ_ASC]		= IO_IRQ_NR(KN02CA_IO_INR_ASC),
+	[DEC_IRQ_FLOPPY]	= IO_IRQ_NR(KN02CA_IO_INR_FLOPPY),
+	[DEC_IRQ_FPU]		= DEC_CPU_IRQ_NR(DEC_CPU_INR_FPU),
+	[DEC_IRQ_HALT]		= DEC_CPU_IRQ_NR(KN02CA_CPU_INR_HALT),
+	[DEC_IRQ_ISDN]		= IO_IRQ_NR(KN02CA_IO_INR_ISDN),
+	[DEC_IRQ_LANCE]		= IO_IRQ_NR(KN02CA_IO_INR_LANCE),
+	[DEC_IRQ_BUS]		= DEC_CPU_IRQ_NR(KN02CA_CPU_INR_BUS),
+	[DEC_IRQ_PSU]		= -1,
+	[DEC_IRQ_RTC]		= DEC_CPU_IRQ_NR(KN02CA_CPU_INR_RTC),
+	[DEC_IRQ_SCC0]		= IO_IRQ_NR(KN02CA_IO_INR_SCC0),
+	[DEC_IRQ_SCC1]		= -1,
+	[DEC_IRQ_SII]		= -1,
+	[DEC_IRQ_TC0]		= IO_IRQ_NR(KN02CA_IO_INR_TC0),
+	[DEC_IRQ_TC1]		= IO_IRQ_NR(KN02CA_IO_INR_TC1),
+	[DEC_IRQ_TC2]		= -1,
+	[DEC_IRQ_TIMER]		= DEC_CPU_IRQ_NR(KN02CA_CPU_INR_TIMER),
+	[DEC_IRQ_VIDEO]		= IO_IRQ_NR(KN02CA_IO_INR_VIDEO),
+	[DEC_IRQ_ASC_MERR]	= IO_IRQ_NR(IO_INR_ASC_MERR),
+	[DEC_IRQ_ASC_ERR]	= IO_IRQ_NR(IO_INR_ASC_ERR),
+	[DEC_IRQ_ASC_DMA]	= IO_IRQ_NR(IO_INR_ASC_DMA),
+	[DEC_IRQ_FLOPPY_ERR]	= IO_IRQ_NR(IO_INR_FLOPPY_ERR),
+	[DEC_IRQ_ISDN_ERR]	= IO_IRQ_NR(IO_INR_ISDN_ERR),
+	[DEC_IRQ_ISDN_RXDMA]	= IO_IRQ_NR(IO_INR_ISDN_RXDMA),
+	[DEC_IRQ_ISDN_TXDMA]	= IO_IRQ_NR(IO_INR_ISDN_TXDMA),
+	[DEC_IRQ_LANCE_MERR]	= IO_IRQ_NR(IO_INR_LANCE_MERR),
+	[DEC_IRQ_SCC0A_RXERR]	= IO_IRQ_NR(IO_INR_SCC0A_RXERR),
+	[DEC_IRQ_SCC0A_RXDMA]	= IO_IRQ_NR(IO_INR_SCC0A_RXDMA),
+	[DEC_IRQ_SCC0A_TXERR]	= IO_IRQ_NR(IO_INR_SCC0A_TXERR),
+	[DEC_IRQ_SCC0A_TXDMA]	= IO_IRQ_NR(IO_INR_SCC0A_TXDMA),
+	[DEC_IRQ_AB_RXERR]	= IO_IRQ_NR(IO_INR_AB_RXERR),
+	[DEC_IRQ_AB_RXDMA]	= IO_IRQ_NR(IO_INR_AB_RXDMA),
+	[DEC_IRQ_AB_TXERR]	= IO_IRQ_NR(IO_INR_AB_TXERR),
+	[DEC_IRQ_AB_TXDMA]	= IO_IRQ_NR(IO_INR_AB_TXDMA),
+	[DEC_IRQ_SCC1A_RXERR]	= -1,
+	[DEC_IRQ_SCC1A_RXDMA]	= -1,
+	[DEC_IRQ_SCC1A_TXERR]	= -1,
+	[DEC_IRQ_SCC1A_TXDMA]	= -1,
+};
+
+static int_ptr kn02ca_cpu_mask_nr_tbl[][2] __initdata = {
+	{ { .i = DEC_CPU_IRQ_MASK(KN02CA_CPU_INR_BUS) },
+		{ .i = DEC_CPU_IRQ_NR(KN02CA_CPU_INR_BUS) } },
+	{ { .i = DEC_CPU_IRQ_MASK(KN02CA_CPU_INR_RTC) },
+		{ .i = DEC_CPU_IRQ_NR(KN02CA_CPU_INR_RTC) } },
+	{ { .i = DEC_CPU_IRQ_MASK(KN02CA_CPU_INR_CASCADE) },
+		{ .p = kn02xa_io_int } },
+	{ { .i = DEC_CPU_IRQ_ALL },
+		{ .p = cpu_all_int } },
+};
+
+static int_ptr kn02ca_asic_mask_nr_tbl[][2] __initdata = {
+	{ { .i = IO_IRQ_DMA },
+		{ .p = asic_dma_int } },
+	{ { .i = IO_IRQ_MASK(KN02CA_IO_INR_SCC0) },
+		{ .i = IO_IRQ_NR(KN02CA_IO_INR_SCC0) } },
+	{ { .i = IO_IRQ_MASK(KN02CA_IO_INR_ASC) },
+		{ .i = IO_IRQ_NR(KN02CA_IO_INR_ASC) } },
+	{ { .i = IO_IRQ_MASK(KN02CA_IO_INR_LANCE) },
+		{ .i = IO_IRQ_NR(KN02CA_IO_INR_LANCE) } },
+	{ { .i = IO_IRQ_MASK(KN02CA_IO_INR_TC1) },
+		{ .i = IO_IRQ_NR(KN02CA_IO_INR_TC1) } },
+	{ { .i = IO_IRQ_MASK(KN02CA_IO_INR_TC0) },
+		{ .i = IO_IRQ_NR(KN02CA_IO_INR_TC0) } },
+	{ { .i = IO_IRQ_ALL },
+		{ .p = asic_all_int } },
+};
+
+static void __init dec_init_kn02ca(void)
+{
+	/* IRQ routing. */
+	memcpy(&dec_interrupt, &kn02ca_interrupt,
+		sizeof(kn02ca_interrupt));
+
+	/* CPU IRQ priorities. */
+	memcpy(&cpu_mask_nr_tbl, &kn02ca_cpu_mask_nr_tbl,
+		sizeof(kn02ca_cpu_mask_nr_tbl));
+
+	/* I/O ASIC IRQ priorities. */
+	memcpy(&asic_mask_nr_tbl, &kn02ca_asic_mask_nr_tbl,
+		sizeof(kn02ca_asic_mask_nr_tbl));
+
+	mips_cpu_irq_init();
+	init_ioasic_irqs(IO_IRQ_BASE);
+
+}				/* dec_init_kn02ca */
+
+
+/*
+ * Machine-specific initialisation for KN03, aka DS5000/240,
+ * aka 3max+ and DS5900, aka BIGmax.  Also applies to KN05, aka
+ * DS5000/260, aka 4max+ and DS5900/260.
+ */
+static int kn03_interrupt[DEC_NR_INTS] __initdata = {
+	[DEC_IRQ_CASCADE]	= DEC_CPU_IRQ_NR(KN03_CPU_INR_CASCADE),
+	[DEC_IRQ_AB_RECV]	= -1,
+	[DEC_IRQ_AB_XMIT]	= -1,
+	[DEC_IRQ_DZ11]		= -1,
+	[DEC_IRQ_ASC]		= IO_IRQ_NR(KN03_IO_INR_ASC),
+	[DEC_IRQ_FLOPPY]	= -1,
+	[DEC_IRQ_FPU]		= DEC_CPU_IRQ_NR(DEC_CPU_INR_FPU),
+	[DEC_IRQ_HALT]		= DEC_CPU_IRQ_NR(KN03_CPU_INR_HALT),
+	[DEC_IRQ_ISDN]		= -1,
+	[DEC_IRQ_LANCE]		= IO_IRQ_NR(KN03_IO_INR_LANCE),
+	[DEC_IRQ_BUS]		= DEC_CPU_IRQ_NR(KN03_CPU_INR_BUS),
+	[DEC_IRQ_PSU]		= IO_IRQ_NR(KN03_IO_INR_PSU),
+	[DEC_IRQ_RTC]		= DEC_CPU_IRQ_NR(KN03_CPU_INR_RTC),
+	[DEC_IRQ_SCC0]		= IO_IRQ_NR(KN03_IO_INR_SCC0),
+	[DEC_IRQ_SCC1]		= IO_IRQ_NR(KN03_IO_INR_SCC1),
+	[DEC_IRQ_SII]		= -1,
+	[DEC_IRQ_TC0]		= IO_IRQ_NR(KN03_IO_INR_TC0),
+	[DEC_IRQ_TC1]		= IO_IRQ_NR(KN03_IO_INR_TC1),
+	[DEC_IRQ_TC2]		= IO_IRQ_NR(KN03_IO_INR_TC2),
+	[DEC_IRQ_TIMER]		= -1,
+	[DEC_IRQ_VIDEO]		= -1,
+	[DEC_IRQ_ASC_MERR]	= IO_IRQ_NR(IO_INR_ASC_MERR),
+	[DEC_IRQ_ASC_ERR]	= IO_IRQ_NR(IO_INR_ASC_ERR),
+	[DEC_IRQ_ASC_DMA]	= IO_IRQ_NR(IO_INR_ASC_DMA),
+	[DEC_IRQ_FLOPPY_ERR]	= -1,
+	[DEC_IRQ_ISDN_ERR]	= -1,
+	[DEC_IRQ_ISDN_RXDMA]	= -1,
+	[DEC_IRQ_ISDN_TXDMA]	= -1,
+	[DEC_IRQ_LANCE_MERR]	= IO_IRQ_NR(IO_INR_LANCE_MERR),
+	[DEC_IRQ_SCC0A_RXERR]	= IO_IRQ_NR(IO_INR_SCC0A_RXERR),
+	[DEC_IRQ_SCC0A_RXDMA]	= IO_IRQ_NR(IO_INR_SCC0A_RXDMA),
+	[DEC_IRQ_SCC0A_TXERR]	= IO_IRQ_NR(IO_INR_SCC0A_TXERR),
+	[DEC_IRQ_SCC0A_TXDMA]	= IO_IRQ_NR(IO_INR_SCC0A_TXDMA),
+	[DEC_IRQ_AB_RXERR]	= -1,
+	[DEC_IRQ_AB_RXDMA]	= -1,
+	[DEC_IRQ_AB_TXERR]	= -1,
+	[DEC_IRQ_AB_TXDMA]	= -1,
+	[DEC_IRQ_SCC1A_RXERR]	= IO_IRQ_NR(IO_INR_SCC1A_RXERR),
+	[DEC_IRQ_SCC1A_RXDMA]	= IO_IRQ_NR(IO_INR_SCC1A_RXDMA),
+	[DEC_IRQ_SCC1A_TXERR]	= IO_IRQ_NR(IO_INR_SCC1A_TXERR),
+	[DEC_IRQ_SCC1A_TXDMA]	= IO_IRQ_NR(IO_INR_SCC1A_TXDMA),
+};
+
+static int_ptr kn03_cpu_mask_nr_tbl[][2] __initdata = {
+	{ { .i = DEC_CPU_IRQ_MASK(KN03_CPU_INR_BUS) },
+		{ .i = DEC_CPU_IRQ_NR(KN03_CPU_INR_BUS) } },
+	{ { .i = DEC_CPU_IRQ_MASK(KN03_CPU_INR_RTC) },
+		{ .i = DEC_CPU_IRQ_NR(KN03_CPU_INR_RTC) } },
+	{ { .i = DEC_CPU_IRQ_MASK(KN03_CPU_INR_CASCADE) },
+		{ .p = kn03_io_int } },
+	{ { .i = DEC_CPU_IRQ_ALL },
+		{ .p = cpu_all_int } },
+};
+
+static int_ptr kn03_asic_mask_nr_tbl[][2] __initdata = {
+	{ { .i = IO_IRQ_DMA },
+		{ .p = asic_dma_int } },
+	{ { .i = IO_IRQ_MASK(KN03_IO_INR_SCC0) },
+		{ .i = IO_IRQ_NR(KN03_IO_INR_SCC0) } },
+	{ { .i = IO_IRQ_MASK(KN03_IO_INR_SCC1) },
+		{ .i = IO_IRQ_NR(KN03_IO_INR_SCC1) } },
+	{ { .i = IO_IRQ_MASK(KN03_IO_INR_ASC) },
+		{ .i = IO_IRQ_NR(KN03_IO_INR_ASC) } },
+	{ { .i = IO_IRQ_MASK(KN03_IO_INR_LANCE) },
+		{ .i = IO_IRQ_NR(KN03_IO_INR_LANCE) } },
+	{ { .i = IO_IRQ_MASK(KN03_IO_INR_TC2) },
+		{ .i = IO_IRQ_NR(KN03_IO_INR_TC2) } },
+	{ { .i = IO_IRQ_MASK(KN03_IO_INR_TC1) },
+		{ .i = IO_IRQ_NR(KN03_IO_INR_TC1) } },
+	{ { .i = IO_IRQ_MASK(KN03_IO_INR_TC0) },
+		{ .i = IO_IRQ_NR(KN03_IO_INR_TC0) } },
+	{ { .i = IO_IRQ_ALL },
+		{ .p = asic_all_int } },
+};
+
+static void __init dec_init_kn03(void)
+{
+	/* IRQ routing. */
+	memcpy(&dec_interrupt, &kn03_interrupt,
+		sizeof(kn03_interrupt));
+
+	/* CPU IRQ priorities. */
+	memcpy(&cpu_mask_nr_tbl, &kn03_cpu_mask_nr_tbl,
+		sizeof(kn03_cpu_mask_nr_tbl));
+
+	/* I/O ASIC IRQ priorities. */
+	memcpy(&asic_mask_nr_tbl, &kn03_asic_mask_nr_tbl,
+		sizeof(kn03_asic_mask_nr_tbl));
+
+	mips_cpu_irq_init();
+	init_ioasic_irqs(IO_IRQ_BASE);
+
+}				/* dec_init_kn03 */
+
+
+void __init arch_init_irq(void)
+{
+	switch (mips_machtype) {
+	case MACH_DS23100:	/* DS2100/DS3100 Pmin/Pmax */
+		dec_init_kn01();
+		break;
+	case MACH_DS5100:	/* DS5100 MIPSmate */
+		dec_init_kn230();
+		break;
+	case MACH_DS5000_200:	/* DS5000/200 3max */
+		dec_init_kn02();
+		break;
+	case MACH_DS5000_1XX:	/* DS5000/1xx 3min */
+		dec_init_kn02ba();
+		break;
+	case MACH_DS5000_2X0:	/* DS5000/240 3max+ */
+	case MACH_DS5900:	/* DS5900 bigmax */
+		dec_init_kn03();
+		break;
+	case MACH_DS5000_XX:	/* Personal DS5000/xx */
+		dec_init_kn02ca();
+		break;
+	case MACH_DS5800:	/* DS5800 Isis */
+		panic("Don't know how to set this up!");
+		break;
+	case MACH_DS5400:	/* DS5400 MIPSfair */
+		panic("Don't know how to set this up!");
+		break;
+	case MACH_DS5500:	/* DS5500 MIPSfair-2 */
+		panic("Don't know how to set this up!");
+		break;
+	}
+
+	/* Free the FPU interrupt if the exception is present. */
+	if (!cpu_has_nofpuex) {
+		cpu_fpu_mask = 0;
+		dec_interrupt[DEC_IRQ_FPU] = -1;
+	}
+	/* Free the halt interrupt unused on R4k systems.  */
+	if (current_cpu_type() == CPU_R4000SC ||
+	    current_cpu_type() == CPU_R4400SC)
+		dec_interrupt[DEC_IRQ_HALT] = -1;
+
+	/* Register board interrupts: FPU and cascade. */
+	if (IS_ENABLED(CONFIG_MIPS_FP_SUPPORT) &&
+	    dec_interrupt[DEC_IRQ_FPU] >= 0 && cpu_has_fpu) {
+		struct irq_desc *desc_fpu;
+		int irq_fpu;
+
+		irq_fpu = dec_interrupt[DEC_IRQ_FPU];
+		if (request_irq(irq_fpu, no_action, IRQF_NO_THREAD, "fpu",
+				NULL))
+			pr_err("Failed to register fpu interrupt\n");
+		desc_fpu = irq_to_desc(irq_fpu);
+		fpu_kstat_irq = this_cpu_ptr(&desc_fpu->kstat_irqs->cnt);
+	}
+	if (dec_interrupt[DEC_IRQ_CASCADE] >= 0) {
+		if (request_irq(dec_interrupt[DEC_IRQ_CASCADE], no_action,
+				IRQF_NO_THREAD, "cascade", NULL))
+			pr_err("Failed to register cascade interrupt\n");
+	}
+	/* Register the bus error interrupt. */
+	if (dec_interrupt[DEC_IRQ_BUS] >= 0 && busirq_handler) {
+		if (request_irq(dec_interrupt[DEC_IRQ_BUS], busirq_handler,
+				busirq_flags, "bus error", busirq_handler))
+			pr_err("Failed to register bus error interrupt\n");
+	}
+	/* Register the HALT interrupt. */
+	if (dec_interrupt[DEC_IRQ_HALT] >= 0) {
+		if (request_irq(dec_interrupt[DEC_IRQ_HALT], dec_intr_halt,
+				IRQF_NO_THREAD, "halt", NULL))
+			pr_err("Failed to register halt interrupt\n");
+	}
+}