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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>
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‎arch/riscv/include/asm/bug.h‎

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/*
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* Copyright (C) 2012 Regents of the University of California
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#ifndef _ASM_RISCV_BUG_H
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#define _ASM_RISCV_BUG_H
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#include <linux/compiler.h>
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#include <linux/const.h>
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#include <linux/types.h>
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#include <asm/asm.h>
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#ifdef CONFIG_GENERIC_BUG
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#define __BUG_INSN _AC(0x00100073, UL) /* ebreak */
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#ifndef __ASSEMBLY__
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typedef u32 bug_insn_t;
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#ifdef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
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#define __BUG_ENTRY_ADDR INT " 1b - 2b"
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#define __BUG_ENTRY_FILE INT " %0 - 2b"
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#else
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#define __BUG_ENTRY_ADDR RISCV_PTR " 1b"
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#define __BUG_ENTRY_FILE RISCV_PTR " %0"
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#endif
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#ifdef CONFIG_DEBUG_BUGVERBOSE
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#define __BUG_ENTRY \
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__BUG_ENTRY_ADDR "\n\t" \
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__BUG_ENTRY_FILE "\n\t" \
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SHORT " %1"
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#else
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#define __BUG_ENTRY \
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__BUG_ENTRY_ADDR
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#endif
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#define BUG() \
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do { \
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__asm__ __volatile__ ( \
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"1:\n\t" \
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"ebreak\n" \
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".pushsection __bug_table,\"a\"\n\t" \
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"2:\n\t" \
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__BUG_ENTRY "\n\t" \
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".org 2b + %2\n\t" \
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".popsection" \
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: \
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: "i" (__FILE__), "i" (__LINE__), \
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"i" (sizeof(struct bug_entry))); \
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unreachable(); \
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} while (0)
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#endif /* !__ASSEMBLY__ */
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#else /* CONFIG_GENERIC_BUG */
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#ifndef __ASSEMBLY__
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#define BUG() \
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do { \
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__asm__ __volatile__ ("ebreak\n"); \
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unreachable(); \
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} while (0)
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#endif /* !__ASSEMBLY__ */
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#endif /* CONFIG_GENERIC_BUG */
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#define HAVE_ARCH_BUG
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#include <asm-generic/bug.h>
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#ifndef __ASSEMBLY__
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struct pt_regs;
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struct task_struct;
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extern void die(struct pt_regs *regs, const char *str);
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extern void do_trap(struct pt_regs *regs, int signo, int code,
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unsigned long addr, struct task_struct *tsk);
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#endif /* !__ASSEMBLY__ */
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#endif /* _ASM_RISCV_BUG_H */

‎arch/riscv/include/asm/cache.h‎

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/*
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* Copyright (C) 2017 Chen Liqin <liqin.chen@sunplusct.com>
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* Copyright (C) 2012 Regents of the University of California
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#ifndef _ASM_RISCV_CACHE_H
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#define _ASM_RISCV_CACHE_H
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#define L1_CACHE_SHIFT 6
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#define L1_CACHE_BYTES (1 << L1_CACHE_SHIFT)
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#endif /* _ASM_RISCV_CACHE_H */

‎arch/riscv/include/asm/smp.h‎

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/*
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* Copyright (C) 2012 Regents of the University of California
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#ifndef _ASM_RISCV_SMP_H
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#define _ASM_RISCV_SMP_H
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/* This both needs asm-offsets.h and is used when generating it. */
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#ifndef GENERATING_ASM_OFFSETS
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#include <asm/asm-offsets.h>
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#endif
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#include <linux/cpumask.h>
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#include <linux/irqreturn.h>
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#ifdef CONFIG_SMP
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/* SMP initialization hook for setup_arch */
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void __init init_clockevent(void);
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/* SMP initialization hook for setup_arch */
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void __init setup_smp(void);
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/* Hook for the generic smp_call_function_many() routine. */
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void arch_send_call_function_ipi_mask(struct cpumask *mask);
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/* Hook for the generic smp_call_function_single() routine. */
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void arch_send_call_function_single_ipi(int cpu);
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/*
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* This is particularly ugly: it appears we can't actually get the definition
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* of task_struct here, but we need access to the CPU this task is running on.
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* Instead of using C we're using asm-offsets.h to get the current processor
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* ID.
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*/
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#define raw_smp_processor_id() (*((int*)((char*)get_current() + TASK_TI_CPU)))
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/* Interprocessor interrupt handler */
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irqreturn_t handle_ipi(void);
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#endif /* CONFIG_SMP */
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#endif /* _ASM_RISCV_SMP_H */

‎arch/riscv/kernel/cacheinfo.c‎

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/*
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* Copyright (C) 2017 SiFive
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/cacheinfo.h>
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#include <linux/cpu.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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static void ci_leaf_init(struct cacheinfo *this_leaf,
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struct device_node *node,
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enum cache_type type, unsigned int level)
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{
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this_leaf->of_node = node;
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this_leaf->level = level;
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this_leaf->type = type;
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/* not a sector cache */
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this_leaf->physical_line_partition = 1;
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/* TODO: Add to DTS */
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this_leaf->attributes =
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CACHE_WRITE_BACK
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| CACHE_READ_ALLOCATE
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| CACHE_WRITE_ALLOCATE;
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}
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static int __init_cache_level(unsigned int cpu)
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{
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struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
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struct device_node *np = of_cpu_device_node_get(cpu);
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int levels = 0, leaves = 0, level;
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if (of_property_read_bool(np, "cache-size"))
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++leaves;
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if (of_property_read_bool(np, "i-cache-size"))
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++leaves;
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if (of_property_read_bool(np, "d-cache-size"))
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++leaves;
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if (leaves > 0)
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levels = 1;
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while ((np = of_find_next_cache_node(np))) {
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if (!of_device_is_compatible(np, "cache"))
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break;
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if (of_property_read_u32(np, "cache-level", &level))
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break;
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if (level <= levels)
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break;
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if (of_property_read_bool(np, "cache-size"))
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++leaves;
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if (of_property_read_bool(np, "i-cache-size"))
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++leaves;
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if (of_property_read_bool(np, "d-cache-size"))
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++leaves;
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levels = level;
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}
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this_cpu_ci->num_levels = levels;
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this_cpu_ci->num_leaves = leaves;
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return 0;
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}
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static int __populate_cache_leaves(unsigned int cpu)
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{
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struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
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struct cacheinfo *this_leaf = this_cpu_ci->info_list;
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struct device_node *np = of_cpu_device_node_get(cpu);
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int levels = 1, level = 1;
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if (of_property_read_bool(np, "cache-size"))
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ci_leaf_init(this_leaf++, np, CACHE_TYPE_UNIFIED, level);
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if (of_property_read_bool(np, "i-cache-size"))
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ci_leaf_init(this_leaf++, np, CACHE_TYPE_INST, level);
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if (of_property_read_bool(np, "d-cache-size"))
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ci_leaf_init(this_leaf++, np, CACHE_TYPE_DATA, level);
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while ((np = of_find_next_cache_node(np))) {
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if (!of_device_is_compatible(np, "cache"))
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break;
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if (of_property_read_u32(np, "cache-level", &level))
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break;
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if (level <= levels)
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break;
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if (of_property_read_bool(np, "cache-size"))
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ci_leaf_init(this_leaf++, np, CACHE_TYPE_UNIFIED, level);
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if (of_property_read_bool(np, "i-cache-size"))
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ci_leaf_init(this_leaf++, np, CACHE_TYPE_INST, level);
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if (of_property_read_bool(np, "d-cache-size"))
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ci_leaf_init(this_leaf++, np, CACHE_TYPE_DATA, level);
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levels = level;
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}
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return 0;
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}
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DEFINE_SMP_CALL_CACHE_FUNCTION(init_cache_level)
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DEFINE_SMP_CALL_CACHE_FUNCTION(populate_cache_leaves)

‎arch/riscv/kernel/cpu.c‎

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/*
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* Copyright (C) 2012 Regents of the University of California
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/init.h>
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#include <linux/seq_file.h>
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#include <linux/of.h>
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/* Return -1 if not a valid hart */
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int riscv_of_processor_hart(struct device_node *node)
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{
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const char *isa, *status;
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u32 hart;
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if (!of_device_is_compatible(node, "riscv")) {
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pr_warn("Found incompatible CPU\n");
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return -(ENODEV);
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}
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if (of_property_read_u32(node, "reg", &hart)) {
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pr_warn("Found CPU without hart ID\n");
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return -(ENODEV);
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}
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if (hart >= NR_CPUS) {
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pr_info("Found hart ID %d, which is above NR_CPUs. Disabling this hart\n", hart);
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return -(ENODEV);
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}
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if (of_property_read_string(node, "status", &status)) {
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pr_warn("CPU with hartid=%d has no \"status\" property\n", hart);
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return -(ENODEV);
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}
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if (strcmp(status, "okay")) {
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pr_info("CPU with hartid=%d has a non-okay status of \"%s\"\n", hart, status);
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return -(ENODEV);
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}
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if (of_property_read_string(node, "riscv,isa", &isa)) {
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pr_warn("CPU with hartid=%d has no \"riscv,isa\" property\n", hart);
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return -(ENODEV);
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}
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if (isa[0] != 'r' || isa[1] != 'v') {
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pr_warn("CPU with hartid=%d has an invalid ISA of \"%s\"\n", hart, isa);
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return -(ENODEV);
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}
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return hart;
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}
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#ifdef CONFIG_PROC_FS
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static void *c_start(struct seq_file *m, loff_t *pos)
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{
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*pos = cpumask_next(*pos - 1, cpu_online_mask);
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if ((*pos) < nr_cpu_ids)
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return (void *)(uintptr_t)(1 + *pos);
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return NULL;
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}
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static void *c_next(struct seq_file *m, void *v, loff_t *pos)
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{
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(*pos)++;
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return c_start(m, pos);
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}
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static void c_stop(struct seq_file *m, void *v)
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{
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}
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static int c_show(struct seq_file *m, void *v)
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{
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unsigned long hart_id = (unsigned long)v - 1;
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struct device_node *node = of_get_cpu_node(hart_id, NULL);
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const char *compat, *isa, *mmu;
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seq_printf(m, "hart\t: %lu\n", hart_id);
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if (!of_property_read_string(node, "riscv,isa", &isa)
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&& isa[0] == 'r'
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&& isa[1] == 'v')
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seq_printf(m, "isa\t: %s\n", isa);
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if (!of_property_read_string(node, "mmu-type", &mmu)
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&& !strncmp(mmu, "riscv,", 6))
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seq_printf(m, "mmu\t: %s\n", mmu+6);
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if (!of_property_read_string(node, "compatible", &compat)
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&& strcmp(compat, "riscv"))
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seq_printf(m, "uarch\t: %s\n", compat);
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seq_puts(m, "\n");
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return 0;
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}
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const struct seq_operations cpuinfo_op = {
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.start = c_start,
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.next = c_next,
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.stop = c_stop,
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.show = c_show
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};
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#endif /* CONFIG_PROC_FS */

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