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>

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 */

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 */

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 */

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)

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 */