RISC-V: Init and Halt Code

This contains the various __init C functions, the initial assembly
kernel entry point, and the code to reset the system.  When a file was
init-related this patch contains the entire file.

Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>

15 files changed, 1524 insertions, 0 deletions

diff --git a/arch/riscv/include/asm/bug.h b/arch/riscv/include/asm/bug.h
new file mode 100644
index 000000000000..c3e13764a943
--- /dev/null
+++ b/arch/riscv/include/asm/bug.h
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2012 Regents of the University of California
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ */
+
+#ifndef _ASM_RISCV_BUG_H
+#define _ASM_RISCV_BUG_H
+
+#include <linux/compiler.h>
+#include <linux/const.h>
+#include <linux/types.h>
+
+#include <asm/asm.h>
+
+#ifdef CONFIG_GENERIC_BUG
+#define __BUG_INSN	_AC(0x00100073, UL) /* ebreak */
+
+#ifndef __ASSEMBLY__
+typedef u32 bug_insn_t;
+
+#ifdef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
+#define __BUG_ENTRY_ADDR	INT " 1b - 2b"
+#define __BUG_ENTRY_FILE	INT " %0 - 2b"
+#else
+#define __BUG_ENTRY_ADDR	RISCV_PTR " 1b"
+#define __BUG_ENTRY_FILE	RISCV_PTR " %0"
+#endif
+
+#ifdef CONFIG_DEBUG_BUGVERBOSE
+#define __BUG_ENTRY			\
+	__BUG_ENTRY_ADDR "\n\t"		\
+	__BUG_ENTRY_FILE "\n\t"		\
+	SHORT " %1"
+#else
+#define __BUG_ENTRY			\
+	__BUG_ENTRY_ADDR
+#endif
+
+#define BUG()							\
+do {								\
+	__asm__ __volatile__ (					\
+		"1:\n\t"					\
+			"ebreak\n"				\
+			".pushsection __bug_table,\"a\"\n\t"	\
+		"2:\n\t"					\
+			__BUG_ENTRY "\n\t"			\
+			".org 2b + %2\n\t"			\
+			".popsection"				\
+		:						\
+		: "i" (__FILE__), "i" (__LINE__),		\
+		  "i" (sizeof(struct bug_entry)));		\
+	unreachable();						\
+} while (0)
+#endif /* !__ASSEMBLY__ */
+#else /* CONFIG_GENERIC_BUG */
+#ifndef __ASSEMBLY__
+#define BUG()							\
+do {								\
+	__asm__ __volatile__ ("ebreak\n");			\
+	unreachable();						\
+} while (0)
+#endif /* !__ASSEMBLY__ */
+#endif /* CONFIG_GENERIC_BUG */
+
+#define HAVE_ARCH_BUG
+
+#include <asm-generic/bug.h>
+
+#ifndef __ASSEMBLY__
+
+struct pt_regs;
+struct task_struct;
+
+extern void die(struct pt_regs *regs, const char *str);
+extern void do_trap(struct pt_regs *regs, int signo, int code,
+	unsigned long addr, struct task_struct *tsk);
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* _ASM_RISCV_BUG_H */
diff --git a/arch/riscv/include/asm/cache.h b/arch/riscv/include/asm/cache.h
new file mode 100644
index 000000000000..e8f0d1110d74
--- /dev/null
+++ b/arch/riscv/include/asm/cache.h
@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2017 Chen Liqin <liqin.chen@sunplusct.com>
+ * Copyright (C) 2012 Regents of the University of California
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ */
+
+#ifndef _ASM_RISCV_CACHE_H
+#define _ASM_RISCV_CACHE_H
+
+#define L1_CACHE_SHIFT		6
+
+#define L1_CACHE_BYTES		(1 << L1_CACHE_SHIFT)
+
+#endif /* _ASM_RISCV_CACHE_H */
diff --git a/arch/riscv/include/asm/smp.h b/arch/riscv/include/asm/smp.h
new file mode 100644
index 000000000000..85e4220839b0
--- /dev/null
+++ b/arch/riscv/include/asm/smp.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2012 Regents of the University of California
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ */
+
+#ifndef _ASM_RISCV_SMP_H
+#define _ASM_RISCV_SMP_H
+
+/* This both needs asm-offsets.h and is used when generating it. */
+#ifndef GENERATING_ASM_OFFSETS
+#include <asm/asm-offsets.h>
+#endif
+
+#include <linux/cpumask.h>
+#include <linux/irqreturn.h>
+
+#ifdef CONFIG_SMP
+
+/* SMP initialization hook for setup_arch */
+void __init init_clockevent(void);
+
+/* SMP initialization hook for setup_arch */
+void __init setup_smp(void);
+
+/* Hook for the generic smp_call_function_many() routine. */
+void arch_send_call_function_ipi_mask(struct cpumask *mask);
+
+/* Hook for the generic smp_call_function_single() routine. */
+void arch_send_call_function_single_ipi(int cpu);
+
+/*
+ * This is particularly ugly: it appears we can't actually get the definition
+ * of task_struct here, but we need access to the CPU this task is running on.
+ * Instead of using C we're using asm-offsets.h to get the current processor
+ * ID.
+ */
+#define raw_smp_processor_id() (*((int*)((char*)get_current() + TASK_TI_CPU)))
+
+/* Interprocessor interrupt handler */
+irqreturn_t handle_ipi(void);
+
+#endif /* CONFIG_SMP */
+
+#endif /* _ASM_RISCV_SMP_H */
diff --git a/arch/riscv/kernel/cacheinfo.c b/arch/riscv/kernel/cacheinfo.c
new file mode 100644
index 000000000000..10ed2749e246
--- /dev/null
+++ b/arch/riscv/kernel/cacheinfo.c
@@ -0,0 +1,105 @@
+/*
+ * Copyright (C) 2017 SiFive
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ */
+
+#include <linux/cacheinfo.h>
+#include <linux/cpu.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+
+static void ci_leaf_init(struct cacheinfo *this_leaf,
+			 struct device_node *node,
+			 enum cache_type type, unsigned int level)
+{
+	this_leaf->of_node = node;
+	this_leaf->level = level;
+	this_leaf->type = type;
+	/* not a sector cache */
+	this_leaf->physical_line_partition = 1;
+	/* TODO: Add to DTS */
+	this_leaf->attributes =
+		CACHE_WRITE_BACK
+		| CACHE_READ_ALLOCATE
+		| CACHE_WRITE_ALLOCATE;
+}
+
+static int __init_cache_level(unsigned int cpu)
+{
+	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
+	struct device_node *np = of_cpu_device_node_get(cpu);
+	int levels = 0, leaves = 0, level;
+
+	if (of_property_read_bool(np, "cache-size"))
+		++leaves;
+	if (of_property_read_bool(np, "i-cache-size"))
+		++leaves;
+	if (of_property_read_bool(np, "d-cache-size"))
+		++leaves;
+	if (leaves > 0)
+		levels = 1;
+
+	while ((np = of_find_next_cache_node(np))) {
+		if (!of_device_is_compatible(np, "cache"))
+			break;
+		if (of_property_read_u32(np, "cache-level", &level))
+			break;
+		if (level <= levels)
+			break;
+		if (of_property_read_bool(np, "cache-size"))
+			++leaves;
+		if (of_property_read_bool(np, "i-cache-size"))
+			++leaves;
+		if (of_property_read_bool(np, "d-cache-size"))
+			++leaves;
+		levels = level;
+	}
+
+	this_cpu_ci->num_levels = levels;
+	this_cpu_ci->num_leaves = leaves;
+	return 0;
+}
+
+static int __populate_cache_leaves(unsigned int cpu)
+{
+	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
+	struct cacheinfo *this_leaf = this_cpu_ci->info_list;
+	struct device_node *np = of_cpu_device_node_get(cpu);
+	int levels = 1, level = 1;
+
+	if (of_property_read_bool(np, "cache-size"))
+		ci_leaf_init(this_leaf++, np, CACHE_TYPE_UNIFIED, level);
+	if (of_property_read_bool(np, "i-cache-size"))
+		ci_leaf_init(this_leaf++, np, CACHE_TYPE_INST, level);
+	if (of_property_read_bool(np, "d-cache-size"))
+		ci_leaf_init(this_leaf++, np, CACHE_TYPE_DATA, level);
+
+	while ((np = of_find_next_cache_node(np))) {
+		if (!of_device_is_compatible(np, "cache"))
+			break;
+		if (of_property_read_u32(np, "cache-level", &level))
+			break;
+		if (level <= levels)
+			break;
+		if (of_property_read_bool(np, "cache-size"))
+			ci_leaf_init(this_leaf++, np, CACHE_TYPE_UNIFIED, level);
+		if (of_property_read_bool(np, "i-cache-size"))
+			ci_leaf_init(this_leaf++, np, CACHE_TYPE_INST, level);
+		if (of_property_read_bool(np, "d-cache-size"))
+			ci_leaf_init(this_leaf++, np, CACHE_TYPE_DATA, level);
+		levels = level;
+	}
+
+	return 0;
+}
+
+DEFINE_SMP_CALL_CACHE_FUNCTION(init_cache_level)
+DEFINE_SMP_CALL_CACHE_FUNCTION(populate_cache_leaves)
diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
new file mode 100644
index 000000000000..ca6c81e54e37
--- /dev/null
+++ b/arch/riscv/kernel/cpu.c
@@ -0,0 +1,108 @@
+/*
+ * Copyright (C) 2012 Regents of the University of California
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ */
+
+#include <linux/init.h>
+#include <linux/seq_file.h>
+#include <linux/of.h>
+
+/* Return -1 if not a valid hart */
+int riscv_of_processor_hart(struct device_node *node)
+{
+	const char *isa, *status;
+	u32 hart;
+
+	if (!of_device_is_compatible(node, "riscv")) {
+		pr_warn("Found incompatible CPU\n");
+		return -(ENODEV);
+	}
+
+	if (of_property_read_u32(node, "reg", &hart)) {
+		pr_warn("Found CPU without hart ID\n");
+		return -(ENODEV);
+	}
+	if (hart >= NR_CPUS) {
+		pr_info("Found hart ID %d, which is above NR_CPUs.  Disabling this hart\n", hart);
+		return -(ENODEV);
+	}
+
+	if (of_property_read_string(node, "status", &status)) {
+		pr_warn("CPU with hartid=%d has no \"status\" property\n", hart);
+		return -(ENODEV);
+	}
+	if (strcmp(status, "okay")) {
+		pr_info("CPU with hartid=%d has a non-okay status of \"%s\"\n", hart, status);
+		return -(ENODEV);
+	}
+
+	if (of_property_read_string(node, "riscv,isa", &isa)) {
+		pr_warn("CPU with hartid=%d has no \"riscv,isa\" property\n", hart);
+		return -(ENODEV);
+	}
+	if (isa[0] != 'r' || isa[1] != 'v') {
+		pr_warn("CPU with hartid=%d has an invalid ISA of \"%s\"\n", hart, isa);
+		return -(ENODEV);
+	}
+
+	return hart;
+}
+
+#ifdef CONFIG_PROC_FS
+
+static void *c_start(struct seq_file *m, loff_t *pos)
+{
+	*pos = cpumask_next(*pos - 1, cpu_online_mask);
+	if ((*pos) < nr_cpu_ids)
+		return (void *)(uintptr_t)(1 + *pos);
+	return NULL;
+}
+
+static void *c_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	(*pos)++;
+	return c_start(m, pos);
+}
+
+static void c_stop(struct seq_file *m, void *v)
+{
+}
+
+static int c_show(struct seq_file *m, void *v)
+{
+	unsigned long hart_id = (unsigned long)v - 1;
+	struct device_node *node = of_get_cpu_node(hart_id, NULL);
+	const char *compat, *isa, *mmu;
+
+	seq_printf(m, "hart\t: %lu\n", hart_id);
+	if (!of_property_read_string(node, "riscv,isa", &isa)
+	    && isa[0] == 'r'
+	    && isa[1] == 'v')
+		seq_printf(m, "isa\t: %s\n", isa);
+	if (!of_property_read_string(node, "mmu-type", &mmu)
+	    && !strncmp(mmu, "riscv,", 6))
+		seq_printf(m, "mmu\t: %s\n", mmu+6);
+	if (!of_property_read_string(node, "compatible", &compat)
+	    && strcmp(compat, "riscv"))
+		seq_printf(m, "uarch\t: %s\n", compat);
+	seq_puts(m, "\n");
+
+	return 0;
+}
+
+const struct seq_operations cpuinfo_op = {
+	.start	= c_start,
+	.next	= c_next,
+	.stop	= c_stop,
+	.show	= c_show
+};
+
+#endif /* CONFIG_PROC_FS */
diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
new file mode 100644
index 000000000000..76af908f87c1
--- /dev/null
+++ b/arch/riscv/kernel/head.S
@@ -0,0 +1,157 @@
+/*
+ * Copyright (C) 2012 Regents of the University of California
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ */
+
+#include <asm/thread_info.h>
+#include <asm/asm-offsets.h>
+#include <asm/asm.h>
+#include <linux/init.h>
+#include <linux/linkage.h>
+#include <asm/thread_info.h>
+#include <asm/page.h>
+#include <asm/csr.h>
+
+__INIT
+ENTRY(_start)
+	/* Mask all interrupts */
+	csrw sie, zero
+
+	/* Load the global pointer */
+.option push
+.option norelax
+	la gp, __global_pointer$
+.option pop
+
+	/*
+	 * Disable FPU to detect illegal usage of
+	 * floating point in kernel space
+	 */
+	li t0, SR_FS
+	csrc sstatus, t0
+
+	/* Pick one hart to run the main boot sequence */
+	la a3, hart_lottery
+	li a2, 1
+	amoadd.w a3, a2, (a3)
+	bnez a3, .Lsecondary_start
+
+	/* Save hart ID and DTB physical address */
+	mv s0, a0
+	mv s1, a1
+
+	/* Initialize page tables and relocate to virtual addresses */
+	la sp, init_thread_union + THREAD_SIZE
+	call setup_vm
+	call relocate
+
+	/* Restore C environment */
+	la tp, init_task
+	sw s0, TASK_TI_CPU(tp)
+
+	la sp, init_thread_union
+	li a0, ASM_THREAD_SIZE
+	add sp, sp, a0
+
+	/* Start the kernel */
+	mv a0, s0
+	mv a1, s1
+	call sbi_save
+	tail start_kernel
+
+relocate:
+	/* Relocate return address */
+	li a1, PAGE_OFFSET
+	la a0, _start
+	sub a1, a1, a0
+	add ra, ra, a1
+
+	/* Point stvec to virtual address of intruction after sptbr write */
+	la a0, 1f
+	add a0, a0, a1
+	csrw stvec, a0
+
+	/* Compute sptbr for kernel page tables, but don't load it yet */
+	la a2, swapper_pg_dir
+	srl a2, a2, PAGE_SHIFT
+	li a1, SPTBR_MODE
+	or a2, a2, a1
+
+	/*
+	 * Load trampoline page directory, which will cause us to trap to
+	 * stvec if VA != PA, or simply fall through if VA == PA
+	 */
+	la a0, trampoline_pg_dir
+	srl a0, a0, PAGE_SHIFT
+	or a0, a0, a1
+	sfence.vma
+	csrw sptbr, a0
+1:
+	/* Set trap vector to spin forever to help debug */
+	la a0, .Lsecondary_park
+	csrw stvec, a0
+
+	/* Reload the global pointer */
+.option push
+.option norelax
+	la gp, __global_pointer$
+.option pop
+
+	/* Switch to kernel page tables */
+	csrw sptbr, a2
+
+	ret
+
+.Lsecondary_start:
+#ifdef CONFIG_SMP
+	li a1, CONFIG_NR_CPUS
+	bgeu a0, a1, .Lsecondary_park
+
+	/* Set trap vector to spin forever to help debug */
+	la a3, .Lsecondary_park
+	csrw stvec, a3
+
+	slli a3, a0, LGREG
+	la a1, __cpu_up_stack_pointer
+	la a2, __cpu_up_task_pointer
+	add a1, a3, a1
+	add a2, a3, a2
+
+	/*
+	 * This hart didn't win the lottery, so we wait for the winning hart to
+	 * get far enough along the boot process that it should continue.
+	 */
+.Lwait_for_cpu_up:
+	/* FIXME: We should WFI to save some energy here. */
+	REG_L sp, (a1)
+	REG_L tp, (a2)
+	beqz sp, .Lwait_for_cpu_up
+	beqz tp, .Lwait_for_cpu_up
+	fence
+
+	/* Enable virtual memory and relocate to virtual address */
+	call relocate
+
+	tail smp_callin
+#endif
+
+.Lsecondary_park:
+	/* We lack SMP support or have too many harts, so park this hart */
+	wfi
+	j .Lsecondary_park
+END(_start)
+
+__PAGE_ALIGNED_BSS
+	/* Empty zero page */
+	.balign PAGE_SIZE
+ENTRY(empty_zero_page)
+	.fill (empty_zero_page + PAGE_SIZE) - ., 1, 0x00
+END(empty_zero_page)
diff --git a/arch/riscv/kernel/irq.c b/arch/riscv/kernel/irq.c
new file mode 100644
index 000000000000..328718e8026e
--- /dev/null
+++ b/arch/riscv/kernel/irq.c
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2012 Regents of the University of California
+ * Copyright (C) 2017 SiFive
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/irqchip.h>
+#include <linux/irqdomain.h>
+
+#ifdef CONFIG_RISCV_INTC
+#include <linux/irqchip/irq-riscv-intc.h>
+#endif
+
+void __init init_IRQ(void)
+{
+	irqchip_init();
+}
+
+asmlinkage void __irq_entry do_IRQ(unsigned int cause, struct pt_regs *regs)
+{
+#ifdef CONFIG_RISCV_INTC
+	/*
+	 * FIXME: We don't want a direct call to riscv_intc_irq here.  The plan
+	 * is to put an IRQ domain here and let the interrupt controller
+	 * register with that, but I poked around the arm64 code a bit and
+	 * there might be a better way to do it (ie, something fully generic).
+	 */
+	riscv_intc_irq(cause, regs);
+#endif
+}
diff --git a/arch/riscv/kernel/reset.c b/arch/riscv/kernel/reset.c
new file mode 100644
index 000000000000..2a53d26ffdd6
--- /dev/null
+++ b/arch/riscv/kernel/reset.c
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2012 Regents of the University of California
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ */
+
+#include <linux/reboot.h>
+#include <linux/export.h>
+#include <asm/sbi.h>
+
+void (*pm_power_off)(void) = machine_power_off;
+EXPORT_SYMBOL(pm_power_off);
+
+void machine_restart(char *cmd)
+{
+	do_kernel_restart(cmd);
+	while (1);
+}
+
+void machine_halt(void)
+{
+	machine_power_off();
+}
+
+void machine_power_off(void)
+{
+	sbi_shutdown();
+	while (1);
+}
diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
new file mode 100644
index 000000000000..de7db114c315
--- /dev/null
+++ b/arch/riscv/kernel/setup.c
@@ -0,0 +1,257 @@
+/*
+ * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
+ *  Chen Liqin <liqin.chen@sunplusct.com>
+ *  Lennox Wu <lennox.wu@sunplusct.com>
+ * Copyright (C) 2012 Regents of the University of California
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see the file COPYING, or write
+ * to the Free Software Foundation, Inc.,
+ */
+
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/memblock.h>
+#include <linux/sched.h>
+#include <linux/initrd.h>
+#include <linux/console.h>
+#include <linux/screen_info.h>
+#include <linux/of_fdt.h>
+#include <linux/of_platform.h>
+#include <linux/sched/task.h>
+
+#include <asm/setup.h>
+#include <asm/sections.h>
+#include <asm/pgtable.h>
+#include <asm/smp.h>
+#include <asm/sbi.h>
+#include <asm/tlbflush.h>
+#include <asm/thread_info.h>
+
+#ifdef CONFIG_HVC_RISCV_SBI
+#include <asm/hvc_riscv_sbi.h>
+#endif
+
+#ifdef CONFIG_DUMMY_CONSOLE
+struct screen_info screen_info = {
+	.orig_video_lines	= 30,
+	.orig_video_cols	= 80,
+	.orig_video_mode	= 0,
+	.orig_video_ega_bx	= 0,
+	.orig_video_isVGA	= 1,
+	.orig_video_points	= 8
+};
+#endif
+
+#ifdef CONFIG_CMDLINE_BOOL
+static char __initdata builtin_cmdline[COMMAND_LINE_SIZE] = CONFIG_CMDLINE;
+#endif /* CONFIG_CMDLINE_BOOL */
+
+unsigned long va_pa_offset;
+unsigned long pfn_base;
+
+/* The lucky hart to first increment this variable will boot the other cores */
+atomic_t hart_lottery;
+
+#ifdef CONFIG_BLK_DEV_INITRD
+static void __init setup_initrd(void)
+{
+	extern char __initramfs_start[];
+	extern unsigned long __initramfs_size;
+	unsigned long size;
+
+	if (__initramfs_size > 0) {
+		initrd_start = (unsigned long)(&__initramfs_start);
+		initrd_end = initrd_start + __initramfs_size;
+	}
+
+	if (initrd_start >= initrd_end) {
+		printk(KERN_INFO "initrd not found or empty");
+		goto disable;
+	}
+	if (__pa(initrd_end) > PFN_PHYS(max_low_pfn)) {
+		printk(KERN_ERR "initrd extends beyond end of memory");
+		goto disable;
+	}
+
+	size =  initrd_end - initrd_start;
+	memblock_reserve(__pa(initrd_start), size);
+	initrd_below_start_ok = 1;
+
+	printk(KERN_INFO "Initial ramdisk at: 0x%p (%lu bytes)\n",
+		(void *)(initrd_start), size);
+	return;
+disable:
+	pr_cont(" - disabling initrd\n");
+	initrd_start = 0;
+	initrd_end = 0;
+}
+#endif /* CONFIG_BLK_DEV_INITRD */
+
+pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
+pgd_t trampoline_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
+
+#ifndef __PAGETABLE_PMD_FOLDED
+#define NUM_SWAPPER_PMDS ((uintptr_t)-PAGE_OFFSET >> PGDIR_SHIFT)
+pmd_t swapper_pmd[PTRS_PER_PMD*((-PAGE_OFFSET)/PGDIR_SIZE)] __page_aligned_bss;
+pmd_t trampoline_pmd[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
+#endif
+
+asmlinkage void __init setup_vm(void)
+{
+	extern char _start;
+	uintptr_t i;
+	uintptr_t pa = (uintptr_t) &_start;
+	pgprot_t prot = __pgprot(pgprot_val(PAGE_KERNEL) | _PAGE_EXEC);
+
+	va_pa_offset = PAGE_OFFSET - pa;
+	pfn_base = PFN_DOWN(pa);
+
+	/* Sanity check alignment and size */
+	BUG_ON((PAGE_OFFSET % PGDIR_SIZE) != 0);
+	BUG_ON((pa % (PAGE_SIZE * PTRS_PER_PTE)) != 0);
+
+#ifndef __PAGETABLE_PMD_FOLDED
+	trampoline_pg_dir[(PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD] =
+		pfn_pgd(PFN_DOWN((uintptr_t)trampoline_pmd),
+			__pgprot(_PAGE_TABLE));
+	trampoline_pmd[0] = pfn_pmd(PFN_DOWN(pa), prot);
+
+	for (i = 0; i < (-PAGE_OFFSET)/PGDIR_SIZE; ++i) {
+		size_t o = (PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD + i;
+		swapper_pg_dir[o] =
+			pfn_pgd(PFN_DOWN((uintptr_t)swapper_pmd) + i,
+				__pgprot(_PAGE_TABLE));
+	}
+	for (i = 0; i < ARRAY_SIZE(swapper_pmd); i++)
+		swapper_pmd[i] = pfn_pmd(PFN_DOWN(pa + i * PMD_SIZE), prot);
+#else
+	trampoline_pg_dir[(PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD] =
+		pfn_pgd(PFN_DOWN(pa), prot);
+
+	for (i = 0; i < (-PAGE_OFFSET)/PGDIR_SIZE; ++i) {
+		size_t o = (PAGE_OFFSET >> PGDIR_SHIFT) % PTRS_PER_PGD + i;
+		swapper_pg_dir[o] =
+			pfn_pgd(PFN_DOWN(pa + i * PGDIR_SIZE), prot);
+	}
+#endif
+}
+
+void __init sbi_save(unsigned int hartid, void *dtb)
+{
+	early_init_dt_scan(__va(dtb));
+}
+
+/*
+ * Allow the user to manually add a memory region (in case DTS is broken);
+ * "mem_end=nn[KkMmGg]"
+ */
+static int __init mem_end_override(char *p)
+{
+	resource_size_t base, end;
+
+	if (!p)
+		return -EINVAL;
+	base = (uintptr_t) __pa(PAGE_OFFSET);
+	end = memparse(p, &p) & PMD_MASK;
+	if (end == 0)
+		return -EINVAL;
+	memblock_add(base, end - base);
+	return 0;
+}
+early_param("mem_end", mem_end_override);
+
+static void __init setup_bootmem(void)
+{
+	struct memblock_region *reg;
+	phys_addr_t mem_size = 0;
+
+	/* Find the memory region containing the kernel */
+	for_each_memblock(memory, reg) {
+		phys_addr_t vmlinux_end = __pa(_end);
+		phys_addr_t end = reg->base + reg->size;
+
+		if (reg->base <= vmlinux_end && vmlinux_end <= end) {
+			/*
+			 * Reserve from the start of the region to the end of
+			 * the kernel
+			 */
+			memblock_reserve(reg->base, vmlinux_end - reg->base);
+			mem_size = min(reg->size, (phys_addr_t)-PAGE_OFFSET);
+		}
+	}
+	BUG_ON(mem_size == 0);
+
+	set_max_mapnr(PFN_DOWN(mem_size));
+	max_low_pfn = pfn_base + PFN_DOWN(mem_size);
+
+#ifdef CONFIG_BLK_DEV_INITRD
+	setup_initrd();
+#endif /* CONFIG_BLK_DEV_INITRD */
+
+	early_init_fdt_reserve_self();
+	early_init_fdt_scan_reserved_mem();
+	memblock_allow_resize();
+	memblock_dump_all();
+}
+
+void __init setup_arch(char **cmdline_p)
+{
+#if defined(CONFIG_HVC_RISCV_SBI)
+	if (likely(early_console == NULL)) {
+		early_console = &riscv_sbi_early_console_dev;
+		register_console(early_console);
+	}
+#endif
+
+#ifdef CONFIG_CMDLINE_BOOL
+#ifdef CONFIG_CMDLINE_OVERRIDE
+	strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
+#else
+	if (builtin_cmdline[0] != '\0') {
+		/* Append bootloader command line to built-in */
+		strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE);
+		strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE);
+		strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
+	}
+#endif /* CONFIG_CMDLINE_OVERRIDE */
+#endif /* CONFIG_CMDLINE_BOOL */
+	*cmdline_p = boot_command_line;
+
+	parse_early_param();
+
+	init_mm.start_code = (unsigned long) _stext;
+	init_mm.end_code   = (unsigned long) _etext;
+	init_mm.end_data   = (unsigned long) _edata;
+	init_mm.brk        = (unsigned long) _end;
+
+	setup_bootmem();
+	paging_init();
+	unflatten_device_tree();
+
+#ifdef CONFIG_SMP
+	setup_smp();
+#endif
+
+#ifdef CONFIG_DUMMY_CONSOLE
+	conswitchp = &dummy_con;
+#endif
+
+	riscv_fill_hwcap();
+}
+
+static int __init riscv_device_init(void)
+{
+	return of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
+}
+subsys_initcall_sync(riscv_device_init);
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
new file mode 100644
index 000000000000..b4a71ec5906f
--- /dev/null
+++ b/arch/riscv/kernel/smp.c
@@ -0,0 +1,110 @@
+/*
+ * SMP initialisation and IPI support
+ * Based on arch/arm64/kernel/smp.c
+ *
+ * Copyright (C) 2012 ARM Ltd.
+ * Copyright (C) 2015 Regents of the University of California
+ * Copyright (C) 2017 SiFive
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/smp.h>
+#include <linux/sched.h>
+
+#include <asm/sbi.h>
+#include <asm/tlbflush.h>
+#include <asm/cacheflush.h>
+
+/* A collection of single bit ipi messages.  */
+static struct {
+	unsigned long bits ____cacheline_aligned;
+} ipi_data[NR_CPUS] __cacheline_aligned;
+
+enum ipi_message_type {
+	IPI_RESCHEDULE,
+	IPI_CALL_FUNC,
+	IPI_MAX
+};
+
+irqreturn_t handle_ipi(void)
+{
+	unsigned long *pending_ipis = &ipi_data[smp_processor_id()].bits;
+
+	/* Clear pending IPI */
+	csr_clear(sip, SIE_SSIE);
+
+	while (true) {
+		unsigned long ops;
+
+		/* Order bit clearing and data access. */
+		mb();
+
+		ops = xchg(pending_ipis, 0);
+		if (ops == 0)
+			return IRQ_HANDLED;
+
+		if (ops & (1 << IPI_RESCHEDULE))
+			scheduler_ipi();
+
+		if (ops & (1 << IPI_CALL_FUNC))
+			generic_smp_call_function_interrupt();
+
+		BUG_ON((ops >> IPI_MAX) != 0);
+
+		/* Order data access and bit testing. */
+		mb();
+	}
+
+	return IRQ_HANDLED;
+}
+
+static void
+send_ipi_message(const struct cpumask *to_whom, enum ipi_message_type operation)
+{
+	int i;
+
+	mb();
+	for_each_cpu(i, to_whom)
+		set_bit(operation, &ipi_data[i].bits);
+
+	mb();
+	sbi_send_ipi(cpumask_bits(to_whom));
+}
+
+void arch_send_call_function_ipi_mask(struct cpumask *mask)
+{
+	send_ipi_message(mask, IPI_CALL_FUNC);
+}
+
+void arch_send_call_function_single_ipi(int cpu)
+{
+	send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC);
+}
+
+static void ipi_stop(void *unused)
+{
+	while (1)
+		wait_for_interrupt();
+}
+
+void smp_send_stop(void)
+{
+	on_each_cpu(ipi_stop, NULL, 1);
+}
+
+void smp_send_reschedule(int cpu)
+{
+	send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
+}
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
new file mode 100644
index 000000000000..f741458c5a3f
--- /dev/null
+++ b/