text: /*
   * Based on arch/arm/mm/init.c
   *
   * Copyright (C) 1995-2005 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/kernel.h>
  #include <linux/export.h>
  #include <linux/errno.h>
  #include <linux/swap.h>
  #include <linux/init.h>
  #include <linux/bootmem.h>
  #include <linux/mman.h>
  #include <linux/nodemask.h>
  #include <linux/initrd.h>
  #include <linux/gfp.h>
  #include <linux/memblock.h>
  #include <linux/sort.h>
  #include <linux/of_fdt.h>
  #include <linux/dma-mapping.h>
  #include <linux/dma-contiguous.h>
  #include <linux/efi.h>
  #include <linux/swiotlb.h>
  
  #include <asm/fixmap.h>
  #include <asm/memory.h>
  #include <asm/sections.h>
  #include <asm/setup.h>
  #include <asm/sizes.h>
  #include <asm/tlb.h>
  #include <asm/alternative.h>
  
  #include "mm.h"
  
  phys_addr_t memstart_addr __read_mostly = 0;
  phys_addr_t arm64_dma_phys_limit __read_mostly;
  
  #ifdef CONFIG_BLK_DEV_INITRD
  static int __init early_initrd(char *p)
  {
  	unsigned long start, size;
  	char *endp;
  
  	start = memparse(p, &endp);
  	if (*endp == ',') {
  		size = memparse(endp + 1, NULL);
  
  		initrd_start = (unsigned long)__va(start);
  		initrd_end = (unsigned long)__va(start + size);
  	}
  	return 0;
  }
  early_param("initrd", early_initrd);
  #endif
  
  /*
   * Return the maximum physical address for ZONE_DMA (DMA_BIT_MASK(32)). It
   * currently assumes that for memory starting above 4G, 32-bit devices will
   * use a DMA offset.
   */
  static phys_addr_t __init max_zone_dma_phys(void)
  {
  	phys_addr_t offset = memblock_start_of_DRAM() & GENMASK_ULL(63, 32);
  	return min(offset + (1ULL << 32), memblock_end_of_DRAM());
  }
  
  static void __init zone_sizes_init(unsigned long min, unsigned long max)
  {
  	struct memblock_region *reg;
  	unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
  	unsigned long max_dma = min;
  
  	memset(zone_size, 0, sizeof(zone_size));
  
  	/* 4GB maximum for 32-bit only capable devices */
  #ifdef CONFIG_ZONE_DMA
  	max_dma = PFN_DOWN(arm64_dma_phys_limit);
  	zone_size[ZONE_DMA] = max_dma - min;
  #endif
  	zone_size[ZONE_NORMAL] = max - max_dma;
  
  	memcpy(zhole_size, zone_size, sizeof(zhole_size));
  
  	for_each_memblock(memory, reg) {
  		unsigned long start = memblock_region_memory_base_pfn(reg);
  		unsigned long end = memblock_region_memory_end_pfn(reg);
  
  		if (start >= max)
  			continue;
  
  #ifdef CONFIG_ZONE_DMA
  		if (start < max_dma) {
  			unsigned long dma_end = min(end, max_dma);
  			zhole_size[ZONE_DMA] -= dma_end - start;
  		}
  #endif
  		if (end > max_dma) {
  			unsigned long normal_end = min(end, max);
  			unsigned long normal_start = max(start, max_dma);
  			zhole_size[ZONE_NORMAL] -= normal_end - normal_start;
  		}
  	}
  
  	free_area_init_node(0, zone_size, min, zhole_size);
  }
  
  #ifdef CONFIG_HAVE_ARCH_PFN_VALID
  int pfn_valid(unsigned long pfn)
  {
  	return memblock_is_map_memory(pfn << PAGE_SHIFT);
  }
  EXPORT_SYMBOL(pfn_valid);
  #endif
  
  #ifndef CONFIG_SPARSEMEM
  static void __init arm64_memory_present(void)
  {
  }
  #else
  static void __init arm64_memory_present(void)
  {
  	struct memblock_region *reg;
  
  	for_each_memblock(memory, reg)
  		memory_present(0, memblock_region_memory_base_pfn(reg),
  			       memblock_region_memory_end_pfn(reg));
  }
  #endif
  
  static phys_addr_t memory_limit = (phys_addr_t)ULLONG_MAX;
  
  /*
   * Limit the memory size that was specified via FDT.
   */
  static int __init early_mem(char *p)
  {
  	if (!p)
  		return 1;
  
  	memory_limit = memparse(p, &p) & PAGE_MASK;
  	pr_notice("Memory limited to %lldMB\n", memory_limit >> 20);
  
  	return 0;
  }
  early_param("mem", early_mem);
  
  void __init arm64_memblock_init(void)
  {
  	memblock_enforce_memory_limit(memory_limit);
  
  	/*
  	 * Register the kernel text, kernel data, initrd, and initial
  	 * pagetables with memblock.
  	 */
  	memblock_reserve(__pa(_text), _end - _text);
  #ifdef CONFIG_BLK_DEV_INITRD
  	if (initrd_start)
  		memblock_reserve(__virt_to_phys(initrd_start), initrd_end - initrd_start);
  #endif
  
  	early_init_fdt_scan_reserved_mem();
  
  	/* 4GB maximum for 32-bit only capable devices */
  	if (IS_ENABLED(CONFIG_ZONE_DMA))
  		arm64_dma_phys_limit = max_zone_dma_phys();
  	else
  		arm64_dma_phys_limit = PHYS_MASK + 1;
  	dma_contiguous_reserve(arm64_dma_phys_limit);
  
  	memblock_allow_resize();
  	memblock_dump_all();
  }
  
  void __init bootmem_init(void)
  {
  	unsigned long min, max;
  
  	min = PFN_UP(memblock_start_of_DRAM());
  	max = PFN_DOWN(memblock_end_of_DRAM());
  
  	early_memtest(min << PAGE_SHIFT, max << PAGE_SHIFT);
  
  	/*
  	 * Sparsemem tries to allocate bootmem in memory_present(), so must be
  	 * done after the fixed reservations.
  	 */
  	arm64_memory_present();
  
  	sparse_init();
  	zone_sizes_init(min, max);
  
  	high_memory = __va((max << PAGE_SHIFT) - 1) + 1;
  	max_pfn = max_low_pfn = max;
  }
  
  #ifndef CONFIG_SPARSEMEM_VMEMMAP
  static inline void free_memmap(unsigned long start_pfn, unsigned long end_pfn)
  {
  	struct page *start_pg, *end_pg;
  	unsigned long pg, pgend;
  
  	/*
  	 * Convert start_pfn/end_pfn to a struct page pointer.
  	 */
  	start_pg = pfn_to_page(start_pfn - 1) + 1;
  	end_pg = pfn_to_page(end_pfn - 1) + 1;
  
  	/*
  	 * Convert to physical addresses, and round start upwards and end
  	 * downwards.
  	 */
  	pg = (unsigned long)PAGE_ALIGN(__pa(start_pg));
  	pgend = (unsigned long)__pa(end_pg) & PAGE_MASK;
  
  	/*
  	 * If there are free pages between these, free the section of the
  	 * memmap array.
  	 */
  	if (pg < pgend)
  		free_bootmem(pg, pgend - pg);
  }
  
  /*
   * The mem_map array can get very big. Free the unused area of the memory map.
   */
  static void __init free_unused_memmap(void)
  {
  	unsigned long start, prev_end = 0;
  	struct memblock_region *reg;
  
  	for_each_memblock(memory, reg) {
  		start = __phys_to_pfn(reg->base);
  
  #ifdef CONFIG_SPARSEMEM
  		/*
  		 * Take care not to free memmap entries that don't exist due
  		 * to SPARSEMEM sections which aren't present.
  		 */
  		start = min(start, ALIGN(prev_end, PAGES_PER_SECTION));
  #endif
  		/*
  		 * If we had a previous bank, and there is a space between the
  		 * current bank and the previous, free it.
  		 */
  		if (prev_end && prev_end < start)
  			free_memmap(prev_end, start);
  
  		/*
  		 * Align up here since the VM subsystem insists that the
  		 * memmap entries are valid from the bank end aligned to
  		 * MAX_ORDER_NR_PAGES.
  		 */
  		prev_end = ALIGN(__phys_to_pfn(reg->base + reg->size),
  				 MAX_ORDER_NR_PAGES);
  	}
  
  #ifdef CONFIG_SPARSEMEM
  	if (!IS_ALIGNED(prev_end, PAGES_PER_SECTION))
  		free_memmap(prev_end, ALIGN(prev_end, PAGES_PER_SECTION));
  #endif
  }
  #endif	/* !CONFIG_SPARSEMEM_VMEMMAP */
  
  /*
   * mem_init() marks the free areas in the mem_map and tells us how much memory
   * is free.  This is done after various parts of the system have claimed their
   * memory after the kernel image.
   */
  void __init mem_init(void)
  {
  	swiotlb_init(1);
  
  	set_max_mapnr(pfn_to_page(max_pfn) - mem_map);
  
  #ifndef CONFIG_SPARSEMEM_VMEMMAP
  	free_unused_memmap();
  #endif
  	/* this will put all unused low memory onto the freelists */
  	free_all_bootmem();
  
  	mem_init_print_info(NULL);
  
  #define MLK(b, t) b, t, ((t) - (b)) >> 10
  #define MLM(b, t) b, t, ((t) - (b)) >> 20
  #define MLG(b, t) b, t, ((t) - (b)) >> 30
  #define MLK_ROUNDUP(b, t) b, t, DIV_ROUND_UP(((t) - (b)), SZ_1K)
  
  	pr_notice("Virtual kernel memory layout:\n"
  #ifdef CONFIG_KASAN
  		  "    kasan   : 0x%16lx - 0x%16lx   (%6ld GB)\n"
  #endif
  		  "    vmalloc : 0x%16lx - 0x%16lx   (%6ld GB)\n"
  #ifdef CONFIG_SPARSEMEM_VMEMMAP
  		  "    vmemmap : 0x%16lx - 0x%16lx   (%6ld GB maximum)\n"
  		  "              0x%16lx - 0x%16lx   (%6ld MB actual)\n"
  #endif
  		  "    fixed   : 0x%16lx - 0x%16lx   (%6ld KB)\n"
  		  "    PCI I/O : 0x%16lx - 0x%16lx   (%6ld MB)\n"
  		  "    modules : 0x%16lx - 0x%16lx   (%6ld MB)\n"
  		  "    memory  : 0x%16lx - 0x%16lx   (%6ld MB)\n"
  		  "      .init : 0x%p" " - 0x%p" "   (%6ld KB)\n"
  		  "      .text : 0x%p" " - 0x%p" "   (%6ld KB)\n"
  		  "      .data : 0x%p" " - 0x%p" "   (%6ld KB)\n",
  #ifdef CONFIG_KASAN
  		  MLG(KASAN_SHADOW_START, KASAN_SHADOW_END),
  #endif
  		  MLG(VMALLOC_START, VMALLOC_END),
  #ifdef CONFIG_SPARSEMEM_VMEMMAP
  		  MLG(VMEMMAP_START,
  		      VMEMMAP_START + VMEMMAP_SIZE),
  		  MLM((unsigned long)virt_to_page(PAGE_OFFSET),
  		      (unsigned long)virt_to_page(high_memory)),
  #endif
  		  MLK(FIXADDR_START, FIXADDR_TOP),
  		  MLM(PCI_IO_START, PCI_IO_END),
  		  MLM(MODULES_VADDR, MODULES_END),
  		  MLM(PAGE_OFFSET, (unsigned long)high_memory),
  		  MLK_ROUNDUP(__init_begin, __init_end),
  		  MLK_ROUNDUP(_text, _etext),
  		  MLK_ROUNDUP(_sdata, _edata));
  
  #undef MLK
  #undef MLM
  #undef MLK_ROUNDUP
  
  	/*
  	 * Check boundaries twice: Some fundamental inconsistencies can be
  	 * detected at build time already.
  	 */
  #ifdef CONFIG_COMPAT
  	BUILD_BUG_ON(TASK_SIZE_32			> TASK_SIZE_64);
  #endif
  	BUILD_BUG_ON(TASK_SIZE_64			> MODULES_VADDR);
  	BUG_ON(TASK_SIZE_64				> MODULES_VADDR);
  
  	if (PAGE_SIZE >= 16384 && get_num_physpages() <= 128) {
  		extern int sysctl_overcommit_memory;
  		/*
  		 * On a machine this small we won't get anywhere without
  		 * overcommit, so turn it on by default.
  		 */
  		sysctl_overcommit_memory = OVERCOMMIT_ALWAYS;
  	}
  }
  
  void free_initmem(void)
  {
  	fixup_init();
  	free_initmem_default(0);
  }
  
  #ifdef CONFIG_BLK_DEV_INITRD
  
  static int keep_initrd __initdata;
  
  void __init free_initrd_mem(unsigned long start, unsigned long end)
  {
  	if (!keep_initrd)
  		free_reserved_area((void *)start, (void *)end, 0, "initrd");
  }
  
  static int __init keepinitrd_setup(char *__unused)
  {
  	keep_initrd = 1;
  	return 1;
  }
  
  __setup("keepinitrd", keepinitrd_setup);
  #endif
  