LoongArch: Add exception/interrupt handling

Add the exception and interrupt handling machanism for basic LoongArch
support.

Reviewed-by: WANG Xuerui <git@xen0n.name>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

arch/loongarch/include/asm/branch.h

@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef _ASM_BRANCH_H
+#define _ASM_BRANCH_H
+
+#include <asm/ptrace.h>
+
+static inline unsigned long exception_era(struct pt_regs *regs)
+{
+	return regs->csr_era;
+}
+
+static inline int compute_return_era(struct pt_regs *regs)
+{
+	regs->csr_era += 4;
+	return 0;
+}
+
+#endif /* _ASM_BRANCH_H */

arch/loongarch/include/asm/bug.h

@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_BUG_H
+#define __ASM_BUG_H
+
+#include <linux/compiler.h>
+
+#ifdef CONFIG_BUG
+
+#include <asm/break.h>
+
+static inline void __noreturn BUG(void)
+{
+	__asm__ __volatile__("break %0" : : "i" (BRK_BUG));
+	unreachable();
+}
+
+#define HAVE_ARCH_BUG
+
+#endif
+
+#include <asm-generic/bug.h>
+
+#endif /* __ASM_BUG_H */

arch/loongarch/include/asm/entry-common.h

@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef ARCH_LOONGARCH_ENTRY_COMMON_H
+#define ARCH_LOONGARCH_ENTRY_COMMON_H
+
+#include <linux/sched.h>
+#include <linux/processor.h>
+
+static inline bool on_thread_stack(void)
+{
+	return !(((unsigned long)(current->stack) ^ current_stack_pointer) & ~(THREAD_SIZE - 1));
+}
+
+#endif

arch/loongarch/include/asm/hardirq.h

@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef _ASM_HARDIRQ_H
+#define _ASM_HARDIRQ_H
+
+#include <linux/cache.h>
+#include <linux/threads.h>
+#include <linux/irq.h>
+
+extern void ack_bad_irq(unsigned int irq);
+#define ack_bad_irq ack_bad_irq
+
+#define NR_IPI	2
+
+typedef struct {
+	unsigned int ipi_irqs[NR_IPI];
+	unsigned int __softirq_pending;
+} ____cacheline_aligned irq_cpustat_t;
+
+DECLARE_PER_CPU_ALIGNED(irq_cpustat_t, irq_stat);
+
+#endif /* _ASM_HARDIRQ_H */

arch/loongarch/include/asm/hw_irq.h

@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef __ASM_HW_IRQ_H
+#define __ASM_HW_IRQ_H
+
+#include <linux/atomic.h>
+
+extern atomic_t irq_err_count;
+
+/*
+ * interrupt-retrigger: NOP for now. This may not be appropriate for all
+ * machines, we'll see ...
+ */
+
+#endif /* __ASM_HW_IRQ_H */

arch/loongarch/include/asm/irq.h

@@ -0,0 +1,130 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef _ASM_IRQ_H
+#define _ASM_IRQ_H
+
+#include <linux/irqdomain.h>
+#include <linux/irqreturn.h>
+
+#define IRQ_STACK_SIZE			THREAD_SIZE
+#define IRQ_STACK_START			(IRQ_STACK_SIZE - 16)
+
+DECLARE_PER_CPU(unsigned long, irq_stack);
+
+/*
+ * The highest address on the IRQ stack contains a dummy frame which is
+ * structured as follows:
+ *
+ *   top ------------
+ *       | task sp  | <- irq_stack[cpu] + IRQ_STACK_START
+ *       ------------
+ *       |          | <- First frame of IRQ context
+ *       ------------
+ *
+ * task sp holds a copy of the task stack pointer where the struct pt_regs
+ * from exception entry can be found.
+ */
+
+static inline bool on_irq_stack(int cpu, unsigned long sp)
+{
+	unsigned long low = per_cpu(irq_stack, cpu);
+	unsigned long high = low + IRQ_STACK_SIZE;
+
+	return (low <= sp && sp <= high);
+}
+
+int get_ipi_irq(void);
+int get_pmc_irq(void);
+int get_timer_irq(void);
+void spurious_interrupt(void);
+
+#define NR_IRQS_LEGACY 16
+
+#define arch_trigger_cpumask_backtrace arch_trigger_cpumask_backtrace
+void arch_trigger_cpumask_backtrace(const struct cpumask *mask, bool exclude_self);
+
+#define MAX_IO_PICS 2
+#define NR_IRQS	(64 + (256 * MAX_IO_PICS))
+
+#define CORES_PER_EIO_NODE	4
+
+#define LOONGSON_CPU_UART0_VEC		10 /* CPU UART0 */
+#define LOONGSON_CPU_THSENS_VEC		14 /* CPU Thsens */
+#define LOONGSON_CPU_HT0_VEC		16 /* CPU HT0 irq vector base number */
+#define LOONGSON_CPU_HT1_VEC		24 /* CPU HT1 irq vector base number */
+
+/* IRQ number definitions */
+#define LOONGSON_LPC_IRQ_BASE		0
+#define LOONGSON_LPC_LAST_IRQ		(LOONGSON_LPC_IRQ_BASE + 15)
+
+#define LOONGSON_CPU_IRQ_BASE		16
+#define LOONGSON_CPU_LAST_IRQ		(LOONGSON_CPU_IRQ_BASE + 14)
+
+#define LOONGSON_PCH_IRQ_BASE		64
+#define LOONGSON_PCH_ACPI_IRQ		(LOONGSON_PCH_IRQ_BASE + 47)
+#define LOONGSON_PCH_LAST_IRQ		(LOONGSON_PCH_IRQ_BASE + 64 - 1)
+
+#define LOONGSON_MSI_IRQ_BASE		(LOONGSON_PCH_IRQ_BASE + 64)
+#define LOONGSON_MSI_LAST_IRQ		(LOONGSON_PCH_IRQ_BASE + 256 - 1)
+
+#define GSI_MIN_LPC_IRQ		LOONGSON_LPC_IRQ_BASE
+#define GSI_MAX_LPC_IRQ		(LOONGSON_LPC_IRQ_BASE + 16 - 1)
+#define GSI_MIN_CPU_IRQ		LOONGSON_CPU_IRQ_BASE
+#define GSI_MAX_CPU_IRQ		(LOONGSON_CPU_IRQ_BASE + 48 - 1)
+#define GSI_MIN_PCH_IRQ		LOONGSON_PCH_IRQ_BASE
+#define GSI_MAX_PCH_IRQ		(LOONGSON_PCH_IRQ_BASE + 256 - 1)
+
+extern int find_pch_pic(u32 gsi);
+extern int eiointc_get_node(int id);
+
+static inline void eiointc_enable(void)
+{
+	uint64_t misc;
+
+	misc = iocsr_read64(LOONGARCH_IOCSR_MISC_FUNC);
+	misc |= IOCSR_MISC_FUNC_EXT_IOI_EN;
+	iocsr_write64(misc, LOONGARCH_IOCSR_MISC_FUNC);
+}
+
+struct acpi_madt_lio_pic;
+struct acpi_madt_eio_pic;
+struct acpi_madt_ht_pic;
+struct acpi_madt_bio_pic;
+struct acpi_madt_msi_pic;
+struct acpi_madt_lpc_pic;
+
+struct irq_domain *loongarch_cpu_irq_init(void);
+
+struct irq_domain *liointc_acpi_init(struct irq_domain *parent,
+					struct acpi_madt_lio_pic *acpi_liointc);
+struct irq_domain *eiointc_acpi_init(struct irq_domain *parent,
+					struct acpi_madt_eio_pic *acpi_eiointc);
+
+struct irq_domain *htvec_acpi_init(struct irq_domain *parent,
+					struct acpi_madt_ht_pic *acpi_htvec);
+struct irq_domain *pch_lpc_acpi_init(struct irq_domain *parent,
+					struct acpi_madt_lpc_pic *acpi_pchlpc);
+struct irq_domain *pch_msi_acpi_init(struct irq_domain *parent,
+					struct acpi_madt_msi_pic *acpi_pchmsi);
+struct irq_domain *pch_pic_acpi_init(struct irq_domain *parent,
+					struct acpi_madt_bio_pic *acpi_pchpic);
+
+extern struct acpi_madt_lio_pic *acpi_liointc;
+extern struct acpi_madt_eio_pic *acpi_eiointc[MAX_IO_PICS];
+
+extern struct acpi_madt_ht_pic *acpi_htintc;
+extern struct acpi_madt_lpc_pic *acpi_pchlpc;
+extern struct acpi_madt_msi_pic *acpi_pchmsi[MAX_IO_PICS];
+extern struct acpi_madt_bio_pic *acpi_pchpic[MAX_IO_PICS];
+
+extern struct irq_domain *cpu_domain;
+extern struct irq_domain *liointc_domain;
+extern struct irq_domain *pch_lpc_domain;
+extern struct irq_domain *pch_msi_domain[MAX_IO_PICS];
+extern struct irq_domain *pch_pic_domain[MAX_IO_PICS];
+
+#include <asm-generic/irq.h>
+
+#endif /* _ASM_IRQ_H */

arch/loongarch/include/asm/irq_regs.h

@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef __ASM_IRQ_REGS_H
+#define __ASM_IRQ_REGS_H
+
+#define ARCH_HAS_OWN_IRQ_REGS
+
+#include <linux/thread_info.h>
+
+static inline struct pt_regs *get_irq_regs(void)
+{
+	return current_thread_info()->regs;
+}
+
+static inline struct pt_regs *set_irq_regs(struct pt_regs *new_regs)
+{
+	struct pt_regs *old_regs;
+
+	old_regs = get_irq_regs();
+	current_thread_info()->regs = new_regs;
+
+	return old_regs;
+}
+
+#endif /* __ASM_IRQ_REGS_H */

arch/loongarch/include/asm/irqflags.h

@@ -0,0 +1,78 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef _ASM_IRQFLAGS_H
+#define _ASM_IRQFLAGS_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/compiler.h>
+#include <linux/stringify.h>
+#include <asm/compiler.h>
+#include <asm/loongarch.h>
+
+static inline void arch_local_irq_enable(void)
+{
+	u32 flags = CSR_CRMD_IE;
+	__asm__ __volatile__(
+		"csrxchg %[val], %[mask], %[reg]\n\t"
+		: [val] "+r" (flags)
+		: [mask] "r" (CSR_CRMD_IE), [reg] "i" (LOONGARCH_CSR_CRMD)
+		: "memory");
+}
+
+static inline void arch_local_irq_disable(void)
+{
+	u32 flags = 0;
+	__asm__ __volatile__(
+		"csrxchg %[val], %[mask], %[reg]\n\t"
+		: [val] "+r" (flags)
+		: [mask] "r" (CSR_CRMD_IE), [reg] "i" (LOONGARCH_CSR_CRMD)
+		: "memory");
+}
+
+static inline unsigned long arch_local_irq_save(void)
+{
+	u32 flags = 0;
+	__asm__ __volatile__(
+		"csrxchg %[val], %[mask], %[reg]\n\t"
+		: [val] "+r" (flags)
+		: [mask] "r" (CSR_CRMD_IE), [reg] "i" (LOONGARCH_CSR_CRMD)
+		: "memory");
+	return flags;
+}
+
+static inline void arch_local_irq_restore(unsigned long flags)
+{
+	__asm__ __volatile__(
+		"csrxchg %[val], %[mask], %[reg]\n\t"
+		: [val] "+r" (flags)
+		: [mask] "r" (CSR_CRMD_IE), [reg] "i" (LOONGARCH_CSR_CRMD)
+		: "memory");
+}
+
+static inline unsigned long arch_local_save_flags(void)
+{
+	u32 flags;
+	__asm__ __volatile__(
+		"csrrd %[val], %[reg]\n\t"
+		: [val] "=r" (flags)
+		: [reg] "i" (LOONGARCH_CSR_CRMD)
+		: "memory");
+	return flags;
+}
+
+static inline int arch_irqs_disabled_flags(unsigned long flags)
+{
+	return !(flags & CSR_CRMD_IE);
+}
+
+static inline int arch_irqs_disabled(void)
+{
+	return arch_irqs_disabled_flags(arch_local_save_flags());
+}
+
+#endif /* #ifndef __ASSEMBLY__ */
+
+#endif /* _ASM_IRQFLAGS_H */

arch/loongarch/include/asm/kdebug.h

@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef _ASM_LOONGARCH_KDEBUG_H
+#define _ASM_LOONGARCH_KDEBUG_H
+
+#include <linux/notifier.h>
+
+enum die_val {
+	DIE_OOPS = 1,
+	DIE_RI,
+	DIE_FP,
+	DIE_SIMD,
+	DIE_TRAP,
+	DIE_PAGE_FAULT,
+	DIE_BREAK,
+	DIE_SSTEPBP,
+	DIE_UPROBE,
+	DIE_UPROBE_XOL,
+};
+
+#endif /* _ASM_LOONGARCH_KDEBUG_H */

arch/loongarch/include/asm/stackframe.h

@@ -0,0 +1,212 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef _ASM_STACKFRAME_H
+#define _ASM_STACKFRAME_H
+
+#include <linux/threads.h>
+
+#include <asm/asm.h>
+#include <asm/asmmacro.h>
+#include <asm/asm-offsets.h>
+#include <asm/loongarch.h>
+#include <asm/thread_info.h>
+
+/* Make the addition of cfi info a little easier. */
+	.macro cfi_rel_offset reg offset=0 docfi=0
+	.if \docfi
+	.cfi_rel_offset \reg, \offset
+	.endif
+	.endm
+
+	.macro cfi_st reg offset=0 docfi=0
+	cfi_rel_offset \reg, \offset, \docfi
+	LONG_S	\reg, sp, \offset
+	.endm
+
+	.macro cfi_restore reg offset=0 docfi=0
+	.if \docfi
+	.cfi_restore \reg
+	.endif
+	.endm
+
+	.macro cfi_ld reg offset=0 docfi=0
+	LONG_L	\reg, sp, \offset
+	cfi_restore \reg \offset \docfi
+	.endm
+
+	.macro BACKUP_T0T1
+	csrwr	t0, EXCEPTION_KS0
+	csrwr	t1, EXCEPTION_KS1
+	.endm
+
+	.macro RELOAD_T0T1
+	csrrd   t0, EXCEPTION_KS0
+	csrrd   t1, EXCEPTION_KS1
+	.endm
+
+	.macro	SAVE_TEMP docfi=0
+	RELOAD_T0T1
+	cfi_st	t0, PT_R12, \docfi
+	cfi_st	t1, PT_R13, \docfi
+	cfi_st	t2, PT_R14, \docfi
+	cfi_st	t3, PT_R15, \docfi
+	cfi_st	t4, PT_R16, \docfi
+	cfi_st	t5, PT_R17, \docfi
+	cfi_st	t6, PT_R18, \docfi
+	cfi_st	t7, PT_R19, \docfi
+	cfi_st	t8, PT_R20, \docfi
+	.endm
+
+	.macro	SAVE_STATIC docfi=0
+	cfi_st	s0, PT_R23, \docfi
+	cfi_st	s1, PT_R24, \docfi
+	cfi_st	s2, PT_R25, \docfi
+	cfi_st	s3, PT_R26, \docfi
+	cfi_st	s4, PT_R27, \docfi
+	cfi_st	s5, PT_R28, \docfi
+	cfi_st	s6, PT_R29, \docfi
+	cfi_st	s7, PT_R30, \docfi
+	cfi_st	s8, PT_R31, \docfi
+	.endm
+
+/*
+ * get_saved_sp returns the SP for the current CPU by looking in the
+ * kernelsp array for it. It stores the current sp in t0 and loads the
+ * new value in sp.
+ */
+	.macro	get_saved_sp docfi=0
+	la.abs	t1, kernelsp
+	move	t0, sp
+	.if \docfi
+	.cfi_register sp, t0
+	.endif
+	LONG_L	sp, t1, 0
+	.endm
+
+	.macro	set_saved_sp stackp temp temp2
+	la.abs	\temp, kernelsp
+	LONG_S	\stackp, \temp, 0
+	.endm
+
+	.macro	SAVE_SOME docfi=0
+	csrrd	t1, LOONGARCH_CSR_PRMD
+	andi	t1, t1, 0x3	/* extract pplv bit */
+	move	t0, sp
+	beqz	t1, 8f
+	/* Called from user mode, new stack. */
+	get_saved_sp docfi=\docfi
+8:
+	PTR_ADDI sp, sp, -PT_SIZE
+	.if \docfi
+	.cfi_def_cfa sp, 0
+	.endif
+	cfi_st	t0, PT_R3, \docfi
+	cfi_rel_offset  sp, PT_R3, \docfi
+	LONG_S	zero, sp, PT_R0
+	csrrd	t0, LOONGARCH_CSR_PRMD
+	LONG_S	t0, sp, PT_PRMD
+	csrrd	t0, LOONGARCH_CSR_CRMD
+	LONG_S	t0, sp, PT_CRMD
+	csrrd	t0, LOONGARCH_CSR_EUEN
+	LONG_S  t0, sp, PT_EUEN
+	csrrd	t0, LOONGARCH_CSR_ECFG
+	LONG_S	t0, sp, PT_ECFG
+	csrrd	t0, LOONGARCH_CSR_ESTAT
+	PTR_S	t0, sp, PT_ESTAT
+	cfi_st	ra, PT_R1, \docfi
+	cfi_st	a0, PT_R4, \docfi
+	cfi_st	a1, PT_R5, \docfi
+	cfi_st	a2, PT_R6, \docfi
+	cfi_st	a3, PT_R7, \docfi
+	cfi_st	a4, PT_R8, \docfi
+	cfi_st	a5, PT_R9, \docfi
+	cfi_st	a6, PT_R10, \docfi
+	cfi_st	a7, PT_R11, \docfi
+	csrrd	ra, LOONGARCH_CSR_ERA
+	LONG_S	ra, sp, PT_ERA
+	.if \docfi
+	.cfi_rel_offset ra, PT_ERA
+	.endif
+	cfi_st	tp, PT_R2, \docfi
+	cfi_st	fp, PT_R22, \docfi
+
+	/* Set thread_info if we're coming from user mode */
+	csrrd	t0, LOONGARCH_CSR_PRMD
+	andi	t0, t0, 0x3	/* extract pplv bit */
+	beqz	t0, 9f
+
+	li.d	tp, ~_THREAD_MASK
+	and	tp, tp, sp
+	cfi_st  u0, PT_R21, \docfi
+	csrrd	u0, PERCPU_BASE_KS
+9:
+	.endm
+
+	.macro	SAVE_ALL docfi=0
+	SAVE_SOME \docfi
+	SAVE_TEMP \docfi
+	SAVE_STATIC \docfi
+	.endm
+
+	.macro	RESTORE_TEMP docfi=0
+	cfi_ld	t0, PT_R12, \docfi
+	cfi_ld	t1, PT_R13, \docfi
+	cfi_ld	t2, PT_R14, \docfi
+	cfi_ld	t3, PT_R15, \docfi
+	cfi_ld	t4, PT_R16, \docfi
+	cfi_ld	t5, PT_R17, \docfi
+	cfi_ld	t6, PT_R18, \docfi
+	cfi_ld	t7, PT_R19, \docfi
+	cfi_ld	t8, PT_R20, \docfi
+	.endm
+
+	.macro	RESTORE_STATIC docfi=0
+	cfi_ld	s0, PT_R23, \docfi
+	cfi_ld	s1, PT_R24, \docfi
+	cfi_ld	s2, PT_R25, \docfi
+	cfi_ld	s3, PT_R26, \docfi
+	cfi_ld	s4, PT_R27, \docfi
+	cfi_ld	s5, PT_R28, \docfi
+	cfi_ld	s6, PT_R29, \docfi
+	cfi_ld	s7, PT_R30, \docfi
+	cfi_ld	s8, PT_R31, \docfi
+	.endm
+
+	.macro	RESTORE_SOME docfi=0
+	LONG_L	a0, sp, PT_PRMD
+	andi    a0, a0, 0x3	/* extract pplv bit */
+	beqz    a0, 8f
+	cfi_ld  u0, PT_R21, \docfi
+8:
+	LONG_L	a0, sp, PT_ERA
+	csrwr	a0, LOONGARCH_CSR_ERA
+	LONG_L	a0, sp, PT_PRMD
+	csrwr	a0, LOONGARCH_CSR_PRMD
+	cfi_ld	ra, PT_R1, \docfi
+	cfi_ld	a0, PT_R4, \docfi
+	cfi_ld	a1, PT_R5, \docfi
+	cfi_ld	a2, PT_R6, \docfi
+	cfi_ld	a3, PT_R7, \docfi
+	cfi_ld	a4, PT_R8, \docfi
+	cfi_ld	a5, PT_R9, \docfi
+	cfi_ld	a6, PT_R10, \docfi
+	cfi_ld	a7, PT_R11, \docfi
+	cfi_ld	tp, PT_R2, \docfi
+	cfi_ld	fp, PT_R22, \docfi
+	.endm
+
+	.macro	RESTORE_SP_AND_RET docfi=0
+	cfi_ld	sp, PT_R3, \docfi
+	ertn
+	.endm
+
+	.macro	RESTORE_ALL_AND_RET docfi=0
+	RESTORE_STATIC \docfi
+	RESTORE_TEMP \docfi
+	RESTORE_SOME \docfi
+	RESTORE_SP_AND_RET \docfi
+	.endm
+
+#endif /* _ASM_STACKFRAME_H */

arch/loongarch/include/asm/stacktrace.h

@@ -0,0 +1,74 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef _ASM_STACKTRACE_H
+#define _ASM_STACKTRACE_H
+
+#include <asm/asm.h>
+#include <asm/ptrace.h>
+#include <asm/loongarch.h>
+#include <linux/stringify.h>
+
+#define STR_LONG_L    __stringify(LONG_L)
+#define STR_LONG_S    __stringify(LONG_S)
+#define STR_LONGSIZE  __stringify(LONGSIZE)
+
+#define STORE_ONE_REG(r) \
+    STR_LONG_S   " $r" __stringify(r)", %1, "STR_LONGSIZE"*"__stringify(r)"\n\t"
+
+#define CSRRD_ONE_REG(reg) \
+    __stringify(csrrd) " %0, "__stringify(reg)"\n\t"
+
+static __always_inline void prepare_frametrace(struct pt_regs *regs)
+{
+	__asm__ __volatile__(
+		/* Save $r1 */
+		STORE_ONE_REG(1)
+		/* Use $r1 to save PC */
+		"pcaddi	$r1, 0\n\t"
+		STR_LONG_S " $r1, %0\n\t"
+		/* Restore $r1 */
+		STR_LONG_L " $r1, %1, "STR_LONGSIZE"\n\t"
+		STORE_ONE_REG(2)
+		STORE_ONE_REG(3)
+		STORE_ONE_REG(4)
+		STORE_ONE_REG(5)
+		STORE_ONE_REG(6)
+		STORE_ONE_REG(7)
+		STORE_ONE_REG(8)
+		STORE_ONE_REG(9)
+		STORE_ONE_REG(10)
+		STORE_ONE_REG(11)
+		STORE_ONE_REG(12)
+		STORE_ONE_REG(13)
+		STORE_ONE_REG(14)
+		STORE_ONE_REG(15)
+		STORE_ONE_REG(16)
+		STORE_ONE_REG(17)
+		STORE_ONE_REG(18)
+		STORE_ONE_REG(19)
+		STORE_ONE_REG(20)
+		STORE_ONE_REG(21)
+		STORE_ONE_REG(22)
+		STORE_ONE_REG(23)
+		STORE_ONE_REG(24)
+		STORE_ONE_REG(25)
+		STORE_ONE_REG(26)
+		STORE_ONE_REG(27)
+		STORE_ONE_REG(28)
+		STORE_ONE_REG(29)
+		STORE_ONE_REG(30)
+		STORE_ONE_REG(31)
+		: "=m" (regs->csr_era)
+		: "r" (regs->regs)
+		: "memory");
+	__asm__ __volatile__(CSRRD_ONE_REG(LOONGARCH_CSR_BADV) : "=r" (regs->csr_badvaddr));
+	__asm__ __volatile__(CSRRD_ONE_REG(LOONGARCH_CSR_CRMD) : "=r" (regs->csr_crmd));
+	__asm__ __volatile__(CSRRD_ONE_REG(LOONGARCH_CSR_PRMD) : "=r" (regs->csr_prmd));
+	__asm__ __volatile__(CSRRD_ONE_REG(LOONGARCH_CSR_EUEN) : "=r" (regs->csr_euen));
+	__asm__ __volatile__(CSRRD_ONE_REG(LOONGARCH_CSR_ECFG) : "=r" (regs->csr_ecfg));
+	__asm__ __volatile__(CSRRD_ONE_REG(LOONGARCH_CSR_ESTAT) : "=r" (regs->csr_estat));
+}
+
+#endif /* _ASM_STACKTRACE_H */

arch/loongarch/include/uapi/asm/break.h

@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef __UAPI_ASM_BREAK_H
+#define __UAPI_ASM_BREAK_H
+
+#define BRK_DEFAULT		0	/* Used as default */
+#define BRK_BUG			1	/* Used by BUG() */
+#define BRK_KDB			2	/* Used in KDB_ENTER() */
+#define BRK_MATHEMU		3	/* Used by FPU emulator */
+#define BRK_USERBP		4	/* User bp (used by debuggers) */
+#define BRK_SSTEPBP		5	/* User bp (used by debuggers) */
+#define BRK_OVERFLOW		6	/* Overflow check */
+#define BRK_DIVZERO		7	/* Divide by zero check */
+#define BRK_RANGE		8	/* Range error check */
+#define BRK_MULOVFL		9	/* Multiply overflow */
+#define BRK_KPROBE_BP		10	/* Kprobe break */
+#define BRK_KPROBE_SSTEPBP	11	/* Kprobe single step break */
+#define BRK_UPROBE_BP		12	/* See <asm/uprobes.h> */
+#define BRK_UPROBE_XOLBP	13	/* See <asm/uprobes.h> */
+
+#endif /* __UAPI_ASM_BREAK_H */

arch/loongarch/kernel/access-helper.h

@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/uaccess.h>
+
+static inline int __get_inst(u32 *i, u32 *p, bool user)
+{
+	return user ? get_user(*i, (u32 __user *)p) : get_kernel_nofault(*i, p);
+}
+
+static inline int __get_addr(unsigned long *a, unsigned long *p, bool user)
+{
+	return user ? get_user(*a, (unsigned long __user *)p) : get_kernel_nofault(*a, p);
+}

arch/loongarch/kernel/genex.S

@@ -0,0 +1,95 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ *
+ * Derived from MIPS:
+ * Copyright (C) 1994 - 2000, 2001, 2003 Ralf Baechle
+ * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
+ * Copyright (C) 2002, 2007  Maciej W. Rozycki
+ * Copyright (C) 2001, 2012 MIPS Technologies, Inc.  All rights reserved.
+ */
+#include <asm/asm.h>
+#include <asm/asmmacro.h>
+#include <asm/loongarch.h>
+#include <asm/regdef.h>
+#include <asm/fpregdef.h>
+#include <asm/stackframe.h>
+#include <asm/thread_info.h>
+
+	.align	5
+SYM_FUNC_START(__arch_cpu_idle)
+	/* start of rollback region */
+	LONG_L	t0, tp, TI_FLAGS
+	nop
+	andi	t0, t0, _TIF_NEED_RESCHED
+	bnez	t0, 1f
+	nop
+	nop
+	nop
+	idle	0
+	/* end of rollback region */
+1:	jirl	zero, ra, 0
+SYM_FUNC_END(__arch_cpu_idle)
+
+SYM_FUNC_START(handle_vint)
+	BACKUP_T0T1
+	SAVE_ALL
+	la.abs	t1, __arch_cpu_idle
+	LONG_L  t0, sp, PT_ERA
+	/* 32 byte rollback region */
+	ori	t0, t0, 0x1f
+	xori	t0, t0, 0x1f
+	bne	t0, t1, 1f
+	LONG_S  t0, sp, PT_ERA
+1:	move	a0, sp
+	move	a1, sp
+	la.abs	t0, do_vint
+	jirl    ra, t0, 0
+	RESTORE_ALL_AND_RET
+SYM_FUNC_END(handle_vint)
+
+SYM_FUNC_START(except_vec_cex)
+	b	cache_parity_error
+SYM_FUNC_END(except_vec_cex)
+
+	.macro	build_prep_badv
+	csrrd	t0, LOONGARCH_CSR_BADV
+	PTR_S	t0, sp, PT_BVADDR
+	.endm
+
+	.macro	build_prep_fcsr
+	movfcsr2gr	a1, fcsr0
+	.endm
+
+	.macro	build_prep_none
+	.endm
+
+	.macro	BUILD_HANDLER exception handler prep
+	.align	5
+	SYM_FUNC_START(handle_\exception)
+	BACKUP_T0T1
+	SAVE_ALL
+	build_prep_\prep
+	move	a0, sp
+	la.abs	t0, do_\handler
+	jirl    ra, t0, 0
+	RESTORE_ALL_AND_RET
+	SYM_FUNC_END(handle_\exception)
+	.endm
+
+	BUILD_HANDLER ade ade badv
+	BUILD_HANDLER ale ale badv
+	BUILD_HANDLER bp bp none
+	BUILD_HANDLER fpe fpe fcsr
+	BUILD_HANDLER fpu fpu none
+	BUILD_HANDLER lsx lsx none
+	BUILD_HANDLER lasx lasx none
+	BUILD_HANDLER lbt lbt none
+	BUILD_HANDLER ri ri none
+	BUILD_HANDLER watch watch none
+	BUILD_HANDLER reserved reserved none	/* others */
+
+SYM_FUNC_START(handle_sys)
+	la.abs	t0, handle_syscall
+	jirl    zero, t0, 0
+SYM_FUNC_END(handle_sys)

arch/loongarch/kernel/irq.c

@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#include <linux/kernel.h>
+#include <linux/acpi.h>
+#include <linux/atomic.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/irqchip.h>
+#include <linux/kernel_stat.h>
+#include <linux/proc_fs.h>
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/seq_file.h>
+#include <linux/kallsyms.h>
+#include <linux/uaccess.h>
+
+#include <asm/irq.h>
+#include <asm/loongson.h>
+#include <asm/setup.h>
+
+DEFINE_PER_CPU(unsigned long, irq_stack);
+
+struct irq_domain *cpu_domain;
+struct irq_domain *liointc_domain;
+struct irq_domain *pch_lpc_domain;
+struct irq_domain *pch_msi_domain[MAX_IO_PICS];
+struct irq_domain *pch_pic_domain[MAX_IO_PICS];
+
+/*
+ * 'what should we do if we get a hw irq event on an illegal vector'.
+ * each architecture has to answer this themselves.
+ */
+void ack_bad_irq(unsigned int irq)
+{
+	pr_warn("Unexpected IRQ # %d\n", irq);
+}
+
+atomic_t irq_err_count;
+
+asmlinkage void spurious_interrupt(void)
+{
+	atomic_inc(&irq_err_count);
+}
+
+int arch_show_interrupts(struct seq_file *p, int prec)
+{
+	seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
+	return 0;
+}
+
+void __init init_IRQ(void)
+{
+	int i;
+	unsigned int order = get_order(IRQ_STACK_SIZE);
+	struct page *page;
+
+	clear_csr_ecfg(ECFG0_IM);
+	clear_csr_estat(ESTATF_IP);
+
+	irqchip_init();
+
+	for (i = 0; i < NR_IRQS; i++)
+		irq_set_noprobe(i);
+
+	for_each_possible_cpu(i) {
+		page = alloc_pages_node(cpu_to_node(i), GFP_KERNEL, order);
+
+		per_cpu(irq_stack, i) = (unsigned long)page_address(page);
+		pr_debug("CPU%d IRQ stack at 0x%lx - 0x%lx\n", i,
+			per_cpu(irq_stack, i), per_cpu(irq_stack, i) + IRQ_STACK_SIZE);
+	}
+
+	set_csr_ecfg(ECFGF_IP0 | ECFGF_IP1 | ECFGF_IP2 | ECFGF_IPI | ECFGF_PMC);
+}