WSL2-Linux-Kernel/arch/arm64/kernel/setup.c

/*
 * Based on arch/arm/kernel/setup.c
 *
 * Copyright (C) 1995-2001 Russell King
 * Copyright (C) 2012 ARM Ltd.
 *
 * 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/export.h>
#include <linux/kernel.h>
#include <linux/stddef.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/utsname.h>
#include <linux/initrd.h>
#include <linux/console.h>
#include <linux/bootmem.h>
#include <linux/seq_file.h>
#include <linux/screen_info.h>
#include <linux/init.h>
#include <linux/kexec.h>
#include <linux/crash_dump.h>
#include <linux/root_dev.h>
#include <linux/cpu.h>
#include <linux/interrupt.h>
#include <linux/smp.h>
#include <linux/fs.h>
#include <linux/proc_fs.h>
#include <linux/memblock.h>
#include <linux/of_fdt.h>

#include <asm/cputype.h>
#include <asm/elf.h>
#include <asm/cputable.h>
#include <asm/sections.h>
#include <asm/setup.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/traps.h>
#include <asm/memblock.h>

unsigned int processor_id;
EXPORT_SYMBOL(processor_id);

unsigned int elf_hwcap __read_mostly;
EXPORT_SYMBOL_GPL(elf_hwcap);

static const char *cpu_name;
static const char *machine_name;
phys_addr_t __fdt_pointer __initdata;

/*
 * Standard memory resources
 */
static struct resource mem_res[] = {
	{
		.name = "Kernel code",
		.start = 0,
		.end = 0,
		.flags = IORESOURCE_MEM
	},
	{
		.name = "Kernel data",
		.start = 0,
		.end = 0,
		.flags = IORESOURCE_MEM
	}
};

#define kernel_code mem_res[0]
#define kernel_data mem_res[1]

void __init early_print(const char *str, ...)
{
	char buf[256];
	va_list ap;

	va_start(ap, str);
	vsnprintf(buf, sizeof(buf), str, ap);
	va_end(ap);

	printk("%s", buf);
}

static void __init setup_processor(void)
{
	struct cpu_info *cpu_info;

	/*
	 * locate processor in the list of supported processor
	 * types.  The linker builds this table for us from the
	 * entries in arch/arm/mm/proc.S
	 */
	cpu_info = lookup_processor_type(read_cpuid_id());
	if (!cpu_info) {
		printk("CPU configuration botched (ID %08x), unable to continue.\n",
		       read_cpuid_id());
		while (1);
	}

	cpu_name = cpu_info->cpu_name;

	printk("CPU: %s [%08x] revision %d\n",
	       cpu_name, read_cpuid_id(), read_cpuid_id() & 15);

	sprintf(init_utsname()->machine, "aarch64");
	elf_hwcap = 0;
}

static void __init setup_machine_fdt(phys_addr_t dt_phys)
{
	struct boot_param_header *devtree;
	unsigned long dt_root;

	/* Check we have a non-NULL DT pointer */
	if (!dt_phys) {
		early_print("\n"
			"Error: NULL or invalid device tree blob\n"
			"The dtb must be 8-byte aligned and passed in the first 512MB of memory\n"
			"\nPlease check your bootloader.\n");

		while (true)
			cpu_relax();

	}

	devtree = phys_to_virt(dt_phys);

	/* Check device tree validity */
	if (be32_to_cpu(devtree->magic) != OF_DT_HEADER) {
		early_print("\n"
			"Error: invalid device tree blob at physical address 0x%p (virtual address 0x%p)\n"
			"Expected 0x%x, found 0x%x\n"
			"\nPlease check your bootloader.\n",
			dt_phys, devtree, OF_DT_HEADER,
			be32_to_cpu(devtree->magic));

		while (true)
			cpu_relax();
	}

	initial_boot_params = devtree;
	dt_root = of_get_flat_dt_root();

	machine_name = of_get_flat_dt_prop(dt_root, "model", NULL);
	if (!machine_name)
		machine_name = of_get_flat_dt_prop(dt_root, "compatible", NULL);
	if (!machine_name)
		machine_name = "<unknown>";
	pr_info("Machine: %s\n", machine_name);

	/* Retrieve various information from the /chosen node */
	of_scan_flat_dt(early_init_dt_scan_chosen, boot_command_line);
	/* Initialize {size,address}-cells info */
	of_scan_flat_dt(early_init_dt_scan_root, NULL);
	/* Setup memory, calling early_init_dt_add_memory_arch */
	of_scan_flat_dt(early_init_dt_scan_memory, NULL);
}

void __init early_init_dt_add_memory_arch(u64 base, u64 size)
{
	base &= PAGE_MASK;
	size &= PAGE_MASK;
	if (base + size < PHYS_OFFSET) {
		pr_warning("Ignoring memory block 0x%llx - 0x%llx\n",
			   base, base + size);
		return;
	}
	if (base < PHYS_OFFSET) {
		pr_warning("Ignoring memory range 0x%llx - 0x%llx\n",
			   base, PHYS_OFFSET);
		size -= PHYS_OFFSET - base;
		base = PHYS_OFFSET;
	}
	memblock_add(base, size);
}

void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
{
	return __va(memblock_alloc(size, align));
}

/*
 * Limit the memory size that was specified via FDT.
 */
static int __init early_mem(char *p)
{
	phys_addr_t limit;

	if (!p)
		return 1;

	limit = memparse(p, &p) & PAGE_MASK;
	pr_notice("Memory limited to %lldMB\n", limit >> 20);

	memblock_enforce_memory_limit(limit);

	return 0;
}
early_param("mem", early_mem);

static void __init request_standard_resources(void)
{
	struct memblock_region *region;
	struct resource *res;

	kernel_code.start   = virt_to_phys(_text);
	kernel_code.end     = virt_to_phys(_etext - 1);
	kernel_data.start   = virt_to_phys(_sdata);
	kernel_data.end     = virt_to_phys(_end - 1);

	for_each_memblock(memory, region) {
		res = alloc_bootmem_low(sizeof(*res));
		res->name  = "System RAM";
		res->start = __pfn_to_phys(memblock_region_memory_base_pfn(region));
		res->end = __pfn_to_phys(memblock_region_memory_end_pfn(region)) - 1;
		res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;

		request_resource(&iomem_resource, res);

		if (kernel_code.start >= res->start &&
		    kernel_code.end <= res->end)
			request_resource(res, &kernel_code);
		if (kernel_data.start >= res->start &&
		    kernel_data.end <= res->end)
			request_resource(res, &kernel_data);
	}
}

void __init setup_arch(char **cmdline_p)
{
	setup_processor();

	setup_machine_fdt(__fdt_pointer);

	init_mm.start_code = (unsigned long) _text;
	init_mm.end_code   = (unsigned long) _etext;
	init_mm.end_data   = (unsigned long) _edata;
	init_mm.brk	   = (unsigned long) _end;

	*cmdline_p = boot_command_line;

	parse_early_param();

	arm64_memblock_init();

	paging_init();
	request_standard_resources();

	unflatten_device_tree();

#ifdef CONFIG_SMP
	smp_init_cpus();
#endif

#ifdef CONFIG_VT
#if defined(CONFIG_VGA_CONSOLE)
	conswitchp = &vga_con;
#elif defined(CONFIG_DUMMY_CONSOLE)
	conswitchp = &dummy_con;
#endif
#endif
}

static DEFINE_PER_CPU(struct cpu, cpu_data);

static int __init topology_init(void)
{
	int i;

	for_each_possible_cpu(i) {
		struct cpu *cpu = &per_cpu(cpu_data, i);
		cpu->hotpluggable = 1;
		register_cpu(cpu, i);
	}

	return 0;
}
subsys_initcall(topology_init);

static const char *hwcap_str[] = {
	"fp",
	"asimd",
	NULL
};

static int c_show(struct seq_file *m, void *v)
{
	int i;

	seq_printf(m, "Processor\t: %s rev %d (%s)\n",
		   cpu_name, read_cpuid_id() & 15, ELF_PLATFORM);

	for_each_online_cpu(i) {
		/*
		 * glibc reads /proc/cpuinfo to determine the number of
		 * online processors, looking for lines beginning with
		 * "processor".  Give glibc what it expects.
		 */
#ifdef CONFIG_SMP
		seq_printf(m, "processor\t: %d\n", i);
#endif
		seq_printf(m, "BogoMIPS\t: %lu.%02lu\n\n",
			   loops_per_jiffy / (500000UL/HZ),
			   loops_per_jiffy / (5000UL/HZ) % 100);
	}

	/* dump out the processor features */
	seq_puts(m, "Features\t: ");

	for (i = 0; hwcap_str[i]; i++)
		if (elf_hwcap & (1 << i))
			seq_printf(m, "%s ", hwcap_str[i]);

	seq_printf(m, "\nCPU implementer\t: 0x%02x\n", read_cpuid_id() >> 24);
	seq_printf(m, "CPU architecture: AArch64\n");
	seq_printf(m, "CPU variant\t: 0x%x\n", (read_cpuid_id() >> 20) & 15);
	seq_printf(m, "CPU part\t: 0x%03x\n", (read_cpuid_id() >> 4) & 0xfff);
	seq_printf(m, "CPU revision\t: %d\n", read_cpuid_id() & 15);

	seq_puts(m, "\n");

	seq_printf(m, "Hardware\t: %s\n", machine_name);

	return 0;
}

static void *c_start(struct seq_file *m, loff_t *pos)
{
	return *pos < 1 ? (void *)1 : NULL;
}

static void *c_next(struct seq_file *m, void *v, loff_t *pos)
{
	++*pos;
	return NULL;
}

static void c_stop(struct seq_file *m, void *v)
{
}

const struct seq_operations cpuinfo_op = {
	.start	= c_start,
	.next	= c_next,
	.stop	= c_stop,
	.show	= c_show
};