arch/arm64/mm/init.c - kernel/msm-4.19 - Gitiles

 /*
  * 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 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 */
 	if (IS_ENABLED(CONFIG_ZONE_DMA)) {
 		max_dma = PFN_DOWN(arm64_dma_phys_limit);
 		zone_size[ZONE_DMA] = max_dma - min;
 	}
 	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;

 		if (IS_ENABLED(CONFIG_ZONE_DMA) && start < max_dma) {
 			unsigned long dma_end = min(end, max_dma);
 			zhole_size[ZONE_DMA] -= dma_end - start;
 		}

 		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_memory(pfn << PAGE_SHIFT);
 }
 EXPORT_SYMBOL(pfn_valid);
 #endif

 #ifndef CONFIG_SPARSEMEM
 static void arm64_memory_present(void)
 {
 }
 #else
 static void 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"
 		  "    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",
 		  MLG(VMALLOC_START, VMALLOC_END),
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 		  MLG((unsigned long)vmemmap,
 		      (unsigned long)vmemmap + 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);
 	free_alternatives_memory();
 }

 #ifdef CONFIG_BLK_DEV_INITRD

 static int keep_initrd;

 void 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
	/*
	* 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 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 */
	if (IS_ENABLED(CONFIG_ZONE_DMA)) {
	max_dma = PFN_DOWN(arm64_dma_phys_limit);
	zone_size[ZONE_DMA] = max_dma - min;
	}
	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;

	if (IS_ENABLED(CONFIG_ZONE_DMA) && start < max_dma) {
	unsigned long dma_end = min(end, max_dma);
	zhole_size[ZONE_DMA] -= dma_end - start;
	}

	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_memory(pfn << PAGE_SHIFT);
	}
	EXPORT_SYMBOL(pfn_valid);
	#endif

	#ifndef CONFIG_SPARSEMEM
	static void arm64_memory_present(void)
	{
	}
	#else
	static void 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"
	" 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",
	MLG(VMALLOC_START, VMALLOC_END),
	#ifdef CONFIG_SPARSEMEM_VMEMMAP
	MLG((unsigned long)vmemmap,
	(unsigned long)vmemmap + 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);
	free_alternatives_memory();
	}

	#ifdef CONFIG_BLK_DEV_INITRD

	static int keep_initrd;

	void 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