arch/arm/mm/nommu.c - LeafOS-Devices/android_kernel_samsung_gta4xl - Gitiles

 /*
  *  linux/arch/arm/mm/nommu.c
  *
  * ARM uCLinux supporting functions.
  */
 #include <linux/module.h>
 #include <linux/mm.h>
 #include <linux/pagemap.h>
 #include <linux/io.h>
 #include <linux/memblock.h>
 #include <linux/kernel.h>

 #include <asm/cacheflush.h>
 #include <asm/cp15.h>
 #include <asm/sections.h>
 #include <asm/page.h>
 #include <asm/setup.h>
 #include <asm/traps.h>
 #include <asm/mach/arch.h>
 #include <asm/cputype.h>
 #include <asm/mpu.h>
 #include <asm/procinfo.h>

 #include "mm.h"

 unsigned long vectors_base;

 /*
  * empty_zero_page is a special page that is used for
  * zero-initialized data and COW.
  */
 struct page *empty_zero_page;
 EXPORT_SYMBOL(empty_zero_page);

 #ifdef CONFIG_ARM_MPU
 struct mpu_rgn_info mpu_rgn_info;

 /* Region number */
 static void rgnr_write(u32 v)
 {
 	asm("mcr        p15, 0, %0, c6, c2, 0" : : "r" (v));
 }

 /* Data-side / unified region attributes */

 /* Region access control register */
 static void dracr_write(u32 v)
 {
 	asm("mcr        p15, 0, %0, c6, c1, 4" : : "r" (v));
 }

 /* Region size register */
 static void drsr_write(u32 v)
 {
 	asm("mcr        p15, 0, %0, c6, c1, 2" : : "r" (v));
 }

 /* Region base address register */
 static void drbar_write(u32 v)
 {
 	asm("mcr        p15, 0, %0, c6, c1, 0" : : "r" (v));
 }

 static u32 drbar_read(void)
 {
 	u32 v;
 	asm("mrc        p15, 0, %0, c6, c1, 0" : "=r" (v));
 	return v;
 }
 /* Optional instruction-side region attributes */

 /* I-side Region access control register */
 static void iracr_write(u32 v)
 {
 	asm("mcr        p15, 0, %0, c6, c1, 5" : : "r" (v));
 }

 /* I-side Region size register */
 static void irsr_write(u32 v)
 {
 	asm("mcr        p15, 0, %0, c6, c1, 3" : : "r" (v));
 }

 /* I-side Region base address register */
 static void irbar_write(u32 v)
 {
 	asm("mcr        p15, 0, %0, c6, c1, 1" : : "r" (v));
 }

 static unsigned long irbar_read(void)
 {
 	unsigned long v;
 	asm("mrc        p15, 0, %0, c6, c1, 1" : "=r" (v));
 	return v;
 }

 /* MPU initialisation functions */
 void __init adjust_lowmem_bounds_mpu(void)
 {
 	phys_addr_t phys_offset = PHYS_OFFSET;
 	phys_addr_t aligned_region_size, specified_mem_size, rounded_mem_size;
 	struct memblock_region *reg;
 	bool first = true;
 	phys_addr_t mem_start;
 	phys_addr_t mem_end;

 	for_each_memblock(memory, reg) {
 		if (first) {
 			/*
 			 * Initially only use memory continuous from
 			 * PHYS_OFFSET */
 			if (reg->base != phys_offset)
 				panic("First memory bank must be contiguous from PHYS_OFFSET");

 			mem_start = reg->base;
 			mem_end = reg->base + reg->size;
 			specified_mem_size = reg->size;
 			first = false;
 		} else {
 			/*
 			 * memblock auto merges contiguous blocks, remove
 			 * all blocks afterwards in one go (we can't remove
 			 * blocks separately while iterating)
 			 */
 			pr_notice("Ignoring RAM after %pa, memory at %pa ignored\n",
 				  &mem_end, &reg->base);
 			memblock_remove(reg->base, 0 - reg->base);
 			break;
 		}
 	}

 	/*
 	 * MPU has curious alignment requirements: Size must be power of 2, and
 	 * region start must be aligned to the region size
 	 */
 	if (phys_offset != 0)
 		pr_info("PHYS_OFFSET != 0 => MPU Region size constrained by alignment requirements\n");

 	/*
 	 * Maximum aligned region might overflow phys_addr_t if phys_offset is
 	 * 0. Hence we keep everything below 4G until we take the smaller of
 	 * the aligned_region_size and rounded_mem_size, one of which is
 	 * guaranteed to be smaller than the maximum physical address.
 	 */
 	aligned_region_size = (phys_offset - 1) ^ (phys_offset);
 	/* Find the max power-of-two sized region that fits inside our bank */
 	rounded_mem_size = (1 <<  __fls(specified_mem_size)) - 1;

 	/* The actual region size is the smaller of the two */
 	aligned_region_size = aligned_region_size < rounded_mem_size
 				? aligned_region_size + 1
 				: rounded_mem_size + 1;

 	if (aligned_region_size != specified_mem_size) {
 		pr_warn("Truncating memory from %pa to %pa (MPU region constraints)",
 				&specified_mem_size, &aligned_region_size);
 		memblock_remove(mem_start + aligned_region_size,
 				specified_mem_size - aligned_region_size);

 		mem_end = mem_start + aligned_region_size;
 	}

 	pr_debug("MPU Region from %pa size %pa (end %pa))\n",
 		&phys_offset, &aligned_region_size, &mem_end);

 }

 static int mpu_present(void)
 {
 	return ((read_cpuid_ext(CPUID_EXT_MMFR0) & MMFR0_PMSA) == MMFR0_PMSAv7);
 }

 static int mpu_max_regions(void)
 {
 	/*
 	 * We don't support a different number of I/D side regions so if we
 	 * have separate instruction and data memory maps then return
 	 * whichever side has a smaller number of supported regions.
 	 */
 	u32 dregions, iregions, mpuir;
 	mpuir = read_cpuid(CPUID_MPUIR);

 	dregions = iregions = (mpuir & MPUIR_DREGION_SZMASK) >> MPUIR_DREGION;

 	/* Check for separate d-side and i-side memory maps */
 	if (mpuir & MPUIR_nU)
 		iregions = (mpuir & MPUIR_IREGION_SZMASK) >> MPUIR_IREGION;

 	/* Use the smallest of the two maxima */
 	return min(dregions, iregions);
 }

 static int mpu_iside_independent(void)
 {
 	/* MPUIR.nU specifies whether there is *not* a unified memory map */
 	return read_cpuid(CPUID_MPUIR) & MPUIR_nU;
 }

 static int mpu_min_region_order(void)
 {
 	u32 drbar_result, irbar_result;
 	/* We've kept a region free for this probing */
 	rgnr_write(MPU_PROBE_REGION);
 	isb();
 	/*
 	 * As per ARM ARM, write 0xFFFFFFFC to DRBAR to find the minimum
 	 * region order
 	*/
 	drbar_write(0xFFFFFFFC);
 	drbar_result = irbar_result = drbar_read();
 	drbar_write(0x0);
 	/* If the MPU is non-unified, we use the larger of the two minima*/
 	if (mpu_iside_independent()) {
 		irbar_write(0xFFFFFFFC);
 		irbar_result = irbar_read();
 		irbar_write(0x0);
 	}
 	isb(); /* Ensure that MPU region operations have completed */
 	/* Return whichever result is larger */
 	return __ffs(max(drbar_result, irbar_result));
 }

 static int mpu_setup_region(unsigned int number, phys_addr_t start,
 			unsigned int size_order, unsigned int properties)
 {
 	u32 size_data;

 	/* We kept a region free for probing resolution of MPU regions*/
 	if (number > mpu_max_regions() || number == MPU_PROBE_REGION)
 		return -ENOENT;

 	if (size_order > 32)
 		return -ENOMEM;

 	if (size_order < mpu_min_region_order())
 		return -ENOMEM;

 	/* Writing N to bits 5:1 (RSR_SZ)  specifies region size 2^N+1 */
 	size_data = ((size_order - 1) << MPU_RSR_SZ) | 1 << MPU_RSR_EN;

 	dsb(); /* Ensure all previous data accesses occur with old mappings */
 	rgnr_write(number);
 	isb();
 	drbar_write(start);
 	dracr_write(properties);
 	isb(); /* Propagate properties before enabling region */
 	drsr_write(size_data);

 	/* Check for independent I-side registers */
 	if (mpu_iside_independent()) {
 		irbar_write(start);
 		iracr_write(properties);
 		isb();
 		irsr_write(size_data);
 	}
 	isb();

 	/* Store region info (we treat i/d side the same, so only store d) */
 	mpu_rgn_info.rgns[number].dracr = properties;
 	mpu_rgn_info.rgns[number].drbar = start;
 	mpu_rgn_info.rgns[number].drsr = size_data;
 	return 0;
 }

 /*
 * Set up default MPU regions, doing nothing if there is no MPU
 */
 void __init mpu_setup(void)
 {
 	int region_err;
 	if (!mpu_present())
 		return;

 	region_err = mpu_setup_region(MPU_RAM_REGION, PHYS_OFFSET,
 					ilog2(memblock.memory.regions[0].size),
 					MPU_AP_PL1RW_PL0RW | MPU_RGN_NORMAL);
 	if (region_err) {
 		panic("MPU region initialization failure! %d", region_err);
 	} else {
 		pr_info("Using ARMv7 PMSA Compliant MPU. "
 			 "Region independence: %s, Max regions: %d\n",
 			mpu_iside_independent() ? "Yes" : "No",
 			mpu_max_regions());
 	}
 }
 #else
 static void adjust_lowmem_bounds_mpu(void) {}
 static void __init mpu_setup(void) {}
 #endif /* CONFIG_ARM_MPU */

 #ifdef CONFIG_CPU_CP15
 #ifdef CONFIG_CPU_HIGH_VECTOR
 static unsigned long __init setup_vectors_base(void)
 {
 	unsigned long reg = get_cr();

 	set_cr(reg | CR_V);
 	return 0xffff0000;
 }
 #else /* CONFIG_CPU_HIGH_VECTOR */
 /* Write exception base address to VBAR */
 static inline void set_vbar(unsigned long val)
 {
 	asm("mcr p15, 0, %0, c12, c0, 0" : : "r" (val) : "cc");
 }

 /*
  * Security extensions, bits[7:4], permitted values,
  * 0b0000 - not implemented, 0b0001/0b0010 - implemented
  */
 static inline bool security_extensions_enabled(void)
 {
 	/* Check CPUID Identification Scheme before ID_PFR1 read */
 	if ((read_cpuid_id() & 0x000f0000) == 0x000f0000)
 		return !!cpuid_feature_extract(CPUID_EXT_PFR1, 4);
 	return 0;
 }

 static unsigned long __init setup_vectors_base(void)
 {
 	unsigned long base = 0, reg = get_cr();

 	set_cr(reg & ~CR_V);
 	if (security_extensions_enabled()) {
 		if (IS_ENABLED(CONFIG_REMAP_VECTORS_TO_RAM))
 			base = CONFIG_DRAM_BASE;
 		set_vbar(base);
 	} else if (IS_ENABLED(CONFIG_REMAP_VECTORS_TO_RAM)) {
 		if (CONFIG_DRAM_BASE != 0)
 			pr_err("Security extensions not enabled, vectors cannot be remapped to RAM, vectors base will be 0x00000000\n");
 	}

 	return base;
 }
 #endif /* CONFIG_CPU_HIGH_VECTOR */
 #endif /* CONFIG_CPU_CP15 */

 void __init arm_mm_memblock_reserve(void)
 {
 #ifndef CONFIG_CPU_V7M
 	vectors_base = IS_ENABLED(CONFIG_CPU_CP15) ? setup_vectors_base() : 0;
 	/*
 	 * Register the exception vector page.
 	 * some architectures which the DRAM is the exception vector to trap,
 	 * alloc_page breaks with error, although it is not NULL, but "0."
 	 */
 	memblock_reserve(vectors_base, 2 * PAGE_SIZE);
 #else /* ifndef CONFIG_CPU_V7M */
 	/*
 	 * There is no dedicated vector page on V7-M. So nothing needs to be
 	 * reserved here.
 	 */
 #endif
 	/*
 	 * In any case, always ensure address 0 is never used as many things
 	 * get very confused if 0 is returned as a legitimate address.
 	 */
 	memblock_reserve(0, 1);
 }

 void __init adjust_lowmem_bounds(void)
 {
 	phys_addr_t end;
 	adjust_lowmem_bounds_mpu();
 	end = memblock_end_of_DRAM();
 	high_memory = __va(end - 1) + 1;
 	memblock_set_current_limit(end);
 }

 /*
  * paging_init() sets up the page tables, initialises the zone memory
  * maps, and sets up the zero page, bad page and bad page tables.
  */
 void __init paging_init(const struct machine_desc *mdesc)
 {
 	void *zero_page;

 	early_trap_init((void *)vectors_base);
 	mpu_setup();

 	/* allocate the zero page. */
 	zero_page = (void *)memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 	if (!zero_page)
 		panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
 		      __func__, PAGE_SIZE, PAGE_SIZE);

 	bootmem_init();

 	empty_zero_page = virt_to_page(zero_page);
 	flush_dcache_page(empty_zero_page);
 }

 /*
  * We don't need to do anything here for nommu machines.
  */
 void setup_mm_for_reboot(void)
 {
 }

 void flush_dcache_page(struct page *page)
 {
 	__cpuc_flush_dcache_area(page_address(page), PAGE_SIZE);
 }
 EXPORT_SYMBOL(flush_dcache_page);

 void flush_kernel_dcache_page(struct page *page)
 {
 	__cpuc_flush_dcache_area(page_address(page), PAGE_SIZE);
 }
 EXPORT_SYMBOL(flush_kernel_dcache_page);

 void copy_to_user_page(struct vm_area_struct *vma, struct page *page,
 		       unsigned long uaddr, void *dst, const void *src,
 		       unsigned long len)
 {
 	memcpy(dst, src, len);
 	if (vma->vm_flags & VM_EXEC)
 		__cpuc_coherent_user_range(uaddr, uaddr + len);
 }

 void __iomem *__arm_ioremap_pfn(unsigned long pfn, unsigned long offset,
 				size_t size, unsigned int mtype)
 {
 	if (pfn >= (0x100000000ULL >> PAGE_SHIFT))
 		return NULL;
 	return (void __iomem *) (offset + (pfn << PAGE_SHIFT));
 }
 EXPORT_SYMBOL(__arm_ioremap_pfn);

 void __iomem *__arm_ioremap_caller(phys_addr_t phys_addr, size_t size,
 				   unsigned int mtype, void *caller)
 {
 	return (void __iomem *)phys_addr;
 }

 void __iomem * (*arch_ioremap_caller)(phys_addr_t, size_t, unsigned int, void *);

 void __iomem *ioremap(resource_size_t res_cookie, size_t size)
 {
 	return __arm_ioremap_caller(res_cookie, size, MT_DEVICE,
 				    __builtin_return_address(0));
 }
 EXPORT_SYMBOL(ioremap);

 void __iomem *ioremap_cache(resource_size_t res_cookie, size_t size)
 	__alias(ioremap_cached);

 void __iomem *ioremap_cached(resource_size_t res_cookie, size_t size)
 {
 	return __arm_ioremap_caller(res_cookie, size, MT_DEVICE_CACHED,
 				    __builtin_return_address(0));
 }
 EXPORT_SYMBOL(ioremap_cache);
 EXPORT_SYMBOL(ioremap_cached);

 void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size)
 {
 	return __arm_ioremap_caller(res_cookie, size, MT_DEVICE_WC,
 				    __builtin_return_address(0));
 }
 EXPORT_SYMBOL(ioremap_wc);

 #ifdef CONFIG_PCI

 #include <asm/mach/map.h>

 void __iomem *pci_remap_cfgspace(resource_size_t res_cookie, size_t size)
 {
 	return arch_ioremap_caller(res_cookie, size, MT_UNCACHED,
 				   __builtin_return_address(0));
 }
 EXPORT_SYMBOL_GPL(pci_remap_cfgspace);
 #endif

 void *arch_memremap_wb(phys_addr_t phys_addr, size_t size)
 {
 	return (void *)phys_addr;
 }

 void __iounmap(volatile void __iomem *addr)
 {
 }
 EXPORT_SYMBOL(__iounmap);

 void (*arch_iounmap)(volatile void __iomem *);

 void iounmap(volatile void __iomem *addr)
 {
 }
 EXPORT_SYMBOL(iounmap);
	/*
	* linux/arch/arm/mm/nommu.c
	*
	* ARM uCLinux supporting functions.
	*/
	#include <linux/module.h>
	#include <linux/mm.h>
	#include <linux/pagemap.h>
	#include <linux/io.h>
	#include <linux/memblock.h>
	#include <linux/kernel.h>

	#include <asm/cacheflush.h>
	#include <asm/cp15.h>
	#include <asm/sections.h>
	#include <asm/page.h>
	#include <asm/setup.h>
	#include <asm/traps.h>
	#include <asm/mach/arch.h>
	#include <asm/cputype.h>
	#include <asm/mpu.h>
	#include <asm/procinfo.h>

	#include "mm.h"

	unsigned long vectors_base;

	/*
	* empty_zero_page is a special page that is used for
	* zero-initialized data and COW.
	*/
	struct page *empty_zero_page;
	EXPORT_SYMBOL(empty_zero_page);

	#ifdef CONFIG_ARM_MPU
	struct mpu_rgn_info mpu_rgn_info;

	/* Region number */
	static void rgnr_write(u32 v)
	{
	asm("mcr p15, 0, %0, c6, c2, 0" : : "r" (v));
	}

	/* Data-side / unified region attributes */

	/* Region access control register */
	static void dracr_write(u32 v)
	{
	asm("mcr p15, 0, %0, c6, c1, 4" : : "r" (v));
	}

	/* Region size register */
	static void drsr_write(u32 v)
	{
	asm("mcr p15, 0, %0, c6, c1, 2" : : "r" (v));
	}

	/* Region base address register */
	static void drbar_write(u32 v)
	{
	asm("mcr p15, 0, %0, c6, c1, 0" : : "r" (v));
	}

	static u32 drbar_read(void)
	{
	u32 v;
	asm("mrc p15, 0, %0, c6, c1, 0" : "=r" (v));
	return v;
	}
	/* Optional instruction-side region attributes */

	/* I-side Region access control register */
	static void iracr_write(u32 v)
	{
	asm("mcr p15, 0, %0, c6, c1, 5" : : "r" (v));
	}

	/* I-side Region size register */
	static void irsr_write(u32 v)
	{
	asm("mcr p15, 0, %0, c6, c1, 3" : : "r" (v));
	}

	/* I-side Region base address register */
	static void irbar_write(u32 v)
	{
	asm("mcr p15, 0, %0, c6, c1, 1" : : "r" (v));
	}

	static unsigned long irbar_read(void)
	{
	unsigned long v;
	asm("mrc p15, 0, %0, c6, c1, 1" : "=r" (v));
	return v;
	}

	/* MPU initialisation functions */
	void __init adjust_lowmem_bounds_mpu(void)
	{
	phys_addr_t phys_offset = PHYS_OFFSET;
	phys_addr_t aligned_region_size, specified_mem_size, rounded_mem_size;
	struct memblock_region *reg;
	bool first = true;
	phys_addr_t mem_start;
	phys_addr_t mem_end;

	for_each_memblock(memory, reg) {
	if (first) {
	/*
	* Initially only use memory continuous from
	* PHYS_OFFSET */
	if (reg->base != phys_offset)
	panic("First memory bank must be contiguous from PHYS_OFFSET");

	mem_start = reg->base;
	mem_end = reg->base + reg->size;
	specified_mem_size = reg->size;
	first = false;
	} else {
	/*
	* memblock auto merges contiguous blocks, remove
	* all blocks afterwards in one go (we can't remove
	* blocks separately while iterating)
	*/
	pr_notice("Ignoring RAM after %pa, memory at %pa ignored\n",
	&mem_end, &reg->base);
	memblock_remove(reg->base, 0 - reg->base);
	break;
	}
	}

	/*
	* MPU has curious alignment requirements: Size must be power of 2, and
	* region start must be aligned to the region size
	*/
	if (phys_offset != 0)
	pr_info("PHYS_OFFSET != 0 => MPU Region size constrained by alignment requirements\n");

	/*
	* Maximum aligned region might overflow phys_addr_t if phys_offset is
	* 0. Hence we keep everything below 4G until we take the smaller of
	* the aligned_region_size and rounded_mem_size, one of which is
	* guaranteed to be smaller than the maximum physical address.
	*/
	aligned_region_size = (phys_offset - 1) ^ (phys_offset);
	/* Find the max power-of-two sized region that fits inside our bank */
	rounded_mem_size = (1 << __fls(specified_mem_size)) - 1;

	/* The actual region size is the smaller of the two */
	aligned_region_size = aligned_region_size < rounded_mem_size
	? aligned_region_size + 1
	: rounded_mem_size + 1;

	if (aligned_region_size != specified_mem_size) {
	pr_warn("Truncating memory from %pa to %pa (MPU region constraints)",
	&specified_mem_size, &aligned_region_size);
	memblock_remove(mem_start + aligned_region_size,
	specified_mem_size - aligned_region_size);

	mem_end = mem_start + aligned_region_size;
	}

	pr_debug("MPU Region from %pa size %pa (end %pa))\n",
	&phys_offset, &aligned_region_size, &mem_end);

	}

	static int mpu_present(void)
	{
	return ((read_cpuid_ext(CPUID_EXT_MMFR0) & MMFR0_PMSA) == MMFR0_PMSAv7);
	}

	static int mpu_max_regions(void)
	{
	/*
	* We don't support a different number of I/D side regions so if we
	* have separate instruction and data memory maps then return
	* whichever side has a smaller number of supported regions.
	*/
	u32 dregions, iregions, mpuir;
	mpuir = read_cpuid(CPUID_MPUIR);

	dregions = iregions = (mpuir & MPUIR_DREGION_SZMASK) >> MPUIR_DREGION;

	/* Check for separate d-side and i-side memory maps */
	if (mpuir & MPUIR_nU)
	iregions = (mpuir & MPUIR_IREGION_SZMASK) >> MPUIR_IREGION;

	/* Use the smallest of the two maxima */
	return min(dregions, iregions);
	}

	static int mpu_iside_independent(void)
	{
	/* MPUIR.nU specifies whether there is not a unified memory map */
	return read_cpuid(CPUID_MPUIR) & MPUIR_nU;
	}

	static int mpu_min_region_order(void)
	{
	u32 drbar_result, irbar_result;
	/* We've kept a region free for this probing */
	rgnr_write(MPU_PROBE_REGION);
	isb();
	/*
	* As per ARM ARM, write 0xFFFFFFFC to DRBAR to find the minimum
	* region order
	*/
	drbar_write(0xFFFFFFFC);
	drbar_result = irbar_result = drbar_read();
	drbar_write(0x0);
	/* If the MPU is non-unified, we use the larger of the two minima*/
	if (mpu_iside_independent()) {
	irbar_write(0xFFFFFFFC);
	irbar_result = irbar_read();
	irbar_write(0x0);
	}
	isb(); /* Ensure that MPU region operations have completed */
	/* Return whichever result is larger */
	return __ffs(max(drbar_result, irbar_result));
	}

	static int mpu_setup_region(unsigned int number, phys_addr_t start,
	unsigned int size_order, unsigned int properties)
	{
	u32 size_data;

	/* We kept a region free for probing resolution of MPU regions*/
	if (number > mpu_max_regions() \|\| number == MPU_PROBE_REGION)
	return -ENOENT;

	if (size_order > 32)
	return -ENOMEM;

	if (size_order < mpu_min_region_order())
	return -ENOMEM;

	/* Writing N to bits 5:1 (RSR_SZ) specifies region size 2^N+1 */
	size_data = ((size_order - 1) << MPU_RSR_SZ) \| 1 << MPU_RSR_EN;

	dsb(); /* Ensure all previous data accesses occur with old mappings */
	rgnr_write(number);
	isb();
	drbar_write(start);
	dracr_write(properties);
	isb(); /* Propagate properties before enabling region */
	drsr_write(size_data);

	/* Check for independent I-side registers */
	if (mpu_iside_independent()) {
	irbar_write(start);
	iracr_write(properties);
	isb();
	irsr_write(size_data);
	}
	isb();

	/* Store region info (we treat i/d side the same, so only store d) */
	mpu_rgn_info.rgns[number].dracr = properties;
	mpu_rgn_info.rgns[number].drbar = start;
	mpu_rgn_info.rgns[number].drsr = size_data;
	return 0;
	}

	/*
	* Set up default MPU regions, doing nothing if there is no MPU
	*/
	void __init mpu_setup(void)
	{
	int region_err;
	if (!mpu_present())
	return;

	region_err = mpu_setup_region(MPU_RAM_REGION, PHYS_OFFSET,
	ilog2(memblock.memory.regions[0].size),
	MPU_AP_PL1RW_PL0RW \| MPU_RGN_NORMAL);
	if (region_err) {
	panic("MPU region initialization failure! %d", region_err);
	} else {
	pr_info("Using ARMv7 PMSA Compliant MPU. "
	"Region independence: %s, Max regions: %d\n",
	mpu_iside_independent() ? "Yes" : "No",
	mpu_max_regions());
	}
	}
	#else
	static void adjust_lowmem_bounds_mpu(void) {}
	static void __init mpu_setup(void) {}
	#endif /* CONFIG_ARM_MPU */

	#ifdef CONFIG_CPU_CP15
	#ifdef CONFIG_CPU_HIGH_VECTOR
	static unsigned long __init setup_vectors_base(void)
	{
	unsigned long reg = get_cr();

	set_cr(reg \| CR_V);
	return 0xffff0000;
	}
	#else /* CONFIG_CPU_HIGH_VECTOR */
	/* Write exception base address to VBAR */
	static inline void set_vbar(unsigned long val)
	{
	asm("mcr p15, 0, %0, c12, c0, 0" : : "r" (val) : "cc");
	}

	/*
	* Security extensions, bits[7:4], permitted values,
	* 0b0000 - not implemented, 0b0001/0b0010 - implemented
	*/
	static inline bool security_extensions_enabled(void)
	{
	/* Check CPUID Identification Scheme before ID_PFR1 read */
	if ((read_cpuid_id() & 0x000f0000) == 0x000f0000)
	return !!cpuid_feature_extract(CPUID_EXT_PFR1, 4);
	return 0;
	}

	static unsigned long __init setup_vectors_base(void)
	{
	unsigned long base = 0, reg = get_cr();

	set_cr(reg & ~CR_V);
	if (security_extensions_enabled()) {
	if (IS_ENABLED(CONFIG_REMAP_VECTORS_TO_RAM))
	base = CONFIG_DRAM_BASE;
	set_vbar(base);
	} else if (IS_ENABLED(CONFIG_REMAP_VECTORS_TO_RAM)) {
	if (CONFIG_DRAM_BASE != 0)
	pr_err("Security extensions not enabled, vectors cannot be remapped to RAM, vectors base will be 0x00000000\n");
	}

	return base;
	}
	#endif /* CONFIG_CPU_HIGH_VECTOR */
	#endif /* CONFIG_CPU_CP15 */

	void __init arm_mm_memblock_reserve(void)
	{
	#ifndef CONFIG_CPU_V7M
	vectors_base = IS_ENABLED(CONFIG_CPU_CP15) ? setup_vectors_base() : 0;
	/*
	* Register the exception vector page.
	* some architectures which the DRAM is the exception vector to trap,
	* alloc_page breaks with error, although it is not NULL, but "0."
	*/
	memblock_reserve(vectors_base, 2 * PAGE_SIZE);
	#else /* ifndef CONFIG_CPU_V7M */
	/*
	* There is no dedicated vector page on V7-M. So nothing needs to be
	* reserved here.
	*/
	#endif
	/*
	* In any case, always ensure address 0 is never used as many things
	* get very confused if 0 is returned as a legitimate address.
	*/
	memblock_reserve(0, 1);
	}

	void __init adjust_lowmem_bounds(void)
	{
	phys_addr_t end;
	adjust_lowmem_bounds_mpu();
	end = memblock_end_of_DRAM();
	high_memory = __va(end - 1) + 1;
	memblock_set_current_limit(end);
	}

	/*
	* paging_init() sets up the page tables, initialises the zone memory
	* maps, and sets up the zero page, bad page and bad page tables.
	*/
	void __init paging_init(const struct machine_desc *mdesc)
	{
	void *zero_page;

	early_trap_init((void *)vectors_base);
	mpu_setup();

	/* allocate the zero page. */
	zero_page = (void *)memblock_alloc(PAGE_SIZE, PAGE_SIZE);
	if (!zero_page)
	panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
	__func__, PAGE_SIZE, PAGE_SIZE);

	bootmem_init();

	empty_zero_page = virt_to_page(zero_page);
	flush_dcache_page(empty_zero_page);
	}

	/*
	* We don't need to do anything here for nommu machines.
	*/
	void setup_mm_for_reboot(void)
	{
	}

	void flush_dcache_page(struct page *page)
	{
	__cpuc_flush_dcache_area(page_address(page), PAGE_SIZE);
	}
	EXPORT_SYMBOL(flush_dcache_page);

	void flush_kernel_dcache_page(struct page *page)
	{
	__cpuc_flush_dcache_area(page_address(page), PAGE_SIZE);
	}
	EXPORT_SYMBOL(flush_kernel_dcache_page);

	void copy_to_user_page(struct vm_area_struct vma, struct page page,
	unsigned long uaddr, void dst, const void src,
	unsigned long len)
	{
	memcpy(dst, src, len);
	if (vma->vm_flags & VM_EXEC)
	__cpuc_coherent_user_range(uaddr, uaddr + len);
	}

	void __iomem *__arm_ioremap_pfn(unsigned long pfn, unsigned long offset,
	size_t size, unsigned int mtype)
	{
	if (pfn >= (0x100000000ULL >> PAGE_SHIFT))
	return NULL;
	return (void __iomem *) (offset + (pfn << PAGE_SHIFT));
	}
	EXPORT_SYMBOL(__arm_ioremap_pfn);

	void __iomem *__arm_ioremap_caller(phys_addr_t phys_addr, size_t size,
	unsigned int mtype, void *caller)
	{
	return (void __iomem *)phys_addr;
	}

	void __iomem * (arch_ioremap_caller)(phys_addr_t, size_t, unsigned int, void );

	void __iomem *ioremap(resource_size_t res_cookie, size_t size)
	{
	return __arm_ioremap_caller(res_cookie, size, MT_DEVICE,
	__builtin_return_address(0));
	}
	EXPORT_SYMBOL(ioremap);

	void __iomem *ioremap_cache(resource_size_t res_cookie, size_t size)
	__alias(ioremap_cached);

	void __iomem *ioremap_cached(resource_size_t res_cookie, size_t size)
	{
	return __arm_ioremap_caller(res_cookie, size, MT_DEVICE_CACHED,
	__builtin_return_address(0));
	}
	EXPORT_SYMBOL(ioremap_cache);
	EXPORT_SYMBOL(ioremap_cached);

	void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size)
	{
	return __arm_ioremap_caller(res_cookie, size, MT_DEVICE_WC,
	__builtin_return_address(0));
	}
	EXPORT_SYMBOL(ioremap_wc);

	#ifdef CONFIG_PCI

	#include <asm/mach/map.h>

	void __iomem *pci_remap_cfgspace(resource_size_t res_cookie, size_t size)
	{
	return arch_ioremap_caller(res_cookie, size, MT_UNCACHED,
	__builtin_return_address(0));
	}
	EXPORT_SYMBOL_GPL(pci_remap_cfgspace);
	#endif

	void *arch_memremap_wb(phys_addr_t phys_addr, size_t size)
	{
	return (void *)phys_addr;
	}

	void __iounmap(volatile void __iomem *addr)
	{
	}
	EXPORT_SYMBOL(__iounmap);

	void (arch_iounmap)(volatile void __iomem );

	void iounmap(volatile void __iomem *addr)
	{
	}
	EXPORT_SYMBOL(iounmap);