Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 809 insertions, 0 deletions

diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
new file mode 100644
index 000000000..ade055556
--- /dev/null
+++ b/arch/arm/mm/init.c
@@ -0,0 +1,809 @@
+/*
+ *  linux/arch/arm/mm/init.c
+ *
+ *  Copyright (C) 1995-2005 Russell King
+ *
+ * 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.
+ */
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/swap.h>
+#include <linux/init.h>
+#include <linux/bootmem.h>
+#include <linux/mman.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/task.h>
+#include <linux/export.h>
+#include <linux/nodemask.h>
+#include <linux/initrd.h>
+#include <linux/of_fdt.h>
+#include <linux/highmem.h>
+#include <linux/gfp.h>
+#include <linux/memblock.h>
+#include <linux/dma-contiguous.h>
+#include <linux/sizes.h>
+#include <linux/stop_machine.h>
+
+#include <asm/cp15.h>
+#include <asm/mach-types.h>
+#include <asm/memblock.h>
+#include <asm/memory.h>
+#include <asm/prom.h>
+#include <asm/sections.h>
+#include <asm/setup.h>
+#include <asm/system_info.h>
+#include <asm/tlb.h>
+#include <asm/fixmap.h>
+#include <asm/ptdump.h>
+
+#include <asm/mach/arch.h>
+#include <asm/mach/map.h>
+
+#include "mm.h"
+
+#ifdef CONFIG_CPU_CP15_MMU
+unsigned long __init __clear_cr(unsigned long mask)
+{
+	cr_alignment = cr_alignment & ~mask;
+	return cr_alignment;
+}
+#endif
+
+static phys_addr_t phys_initrd_start __initdata = 0;
+static unsigned long phys_initrd_size __initdata = 0;
+
+static int __init early_initrd(char *p)
+{
+	phys_addr_t start;
+	unsigned long size;
+	char *endp;
+
+	start = memparse(p, &endp);
+	if (*endp == ',') {
+		size = memparse(endp + 1, NULL);
+
+		phys_initrd_start = start;
+		phys_initrd_size = size;
+	}
+	return 0;
+}
+early_param("initrd", early_initrd);
+
+static int __init parse_tag_initrd(const struct tag *tag)
+{
+	pr_warn("ATAG_INITRD is deprecated; "
+		"please update your bootloader.\n");
+	phys_initrd_start = __virt_to_phys(tag->u.initrd.start);
+	phys_initrd_size = tag->u.initrd.size;
+	return 0;
+}
+
+__tagtable(ATAG_INITRD, parse_tag_initrd);
+
+static int __init parse_tag_initrd2(const struct tag *tag)
+{
+	phys_initrd_start = tag->u.initrd.start;
+	phys_initrd_size = tag->u.initrd.size;
+	return 0;
+}
+
+__tagtable(ATAG_INITRD2, parse_tag_initrd2);
+
+static void __init find_limits(unsigned long *min, unsigned long *max_low,
+			       unsigned long *max_high)
+{
+	*max_low = PFN_DOWN(memblock_get_current_limit());
+	*min = PFN_UP(memblock_start_of_DRAM());
+	*max_high = PFN_DOWN(memblock_end_of_DRAM());
+}
+
+#ifdef CONFIG_ZONE_DMA
+
+phys_addr_t arm_dma_zone_size __read_mostly;
+EXPORT_SYMBOL(arm_dma_zone_size);
+
+/*
+ * The DMA mask corresponding to the maximum bus address allocatable
+ * using GFP_DMA.  The default here places no restriction on DMA
+ * allocations.  This must be the smallest DMA mask in the system,
+ * so a successful GFP_DMA allocation will always satisfy this.
+ */
+phys_addr_t arm_dma_limit;
+unsigned long arm_dma_pfn_limit;
+
+static void __init arm_adjust_dma_zone(unsigned long *size, unsigned long *hole,
+	unsigned long dma_size)
+{
+	if (size[0] <= dma_size)
+		return;
+
+	size[ZONE_NORMAL] = size[0] - dma_size;
+	size[ZONE_DMA] = dma_size;
+	hole[ZONE_NORMAL] = hole[0];
+	hole[ZONE_DMA] = 0;
+}
+#endif
+
+void __init setup_dma_zone(const struct machine_desc *mdesc)
+{
+#ifdef CONFIG_ZONE_DMA
+	if (mdesc->dma_zone_size) {
+		arm_dma_zone_size = mdesc->dma_zone_size;
+		arm_dma_limit = PHYS_OFFSET + arm_dma_zone_size - 1;
+	} else
+		arm_dma_limit = 0xffffffff;
+	arm_dma_pfn_limit = arm_dma_limit >> PAGE_SHIFT;
+#endif
+}
+
+static void __init zone_sizes_init(unsigned long min, unsigned long max_low,
+	unsigned long max_high)
+{
+	unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
+	struct memblock_region *reg;
+
+	/*
+	 * initialise the zones.
+	 */
+	memset(zone_size, 0, sizeof(zone_size));
+
+	/*
+	 * The memory size has already been determined.  If we need
+	 * to do anything fancy with the allocation of this memory
+	 * to the zones, now is the time to do it.
+	 */
+	zone_size[0] = max_low - min;
+#ifdef CONFIG_HIGHMEM
+	zone_size[ZONE_HIGHMEM] = max_high - max_low;
+#endif
+
+	/*
+	 * Calculate the size of the holes.
+	 *  holes = node_size - sum(bank_sizes)
+	 */
+	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_low) {
+			unsigned long low_end = min(end, max_low);
+			zhole_size[0] -= low_end - start;
+		}
+#ifdef CONFIG_HIGHMEM
+		if (end > max_low) {
+			unsigned long high_start = max(start, max_low);
+			zhole_size[ZONE_HIGHMEM] -= end - high_start;
+		}
+#endif
+	}
+
+#ifdef CONFIG_ZONE_DMA
+	/*
+	 * Adjust the sizes according to any special requirements for
+	 * this machine type.
+	 */
+	if (arm_dma_zone_size)
+		arm_adjust_dma_zone(zone_size, zhole_size,
+			arm_dma_zone_size >> PAGE_SHIFT);
+#endif
+
+	free_area_init_node(0, zone_size, min, zhole_size);
+}
+
+#ifdef CONFIG_HAVE_ARCH_PFN_VALID
+int pfn_valid(unsigned long pfn)
+{
+	phys_addr_t addr = __pfn_to_phys(pfn);
+
+	if (__phys_to_pfn(addr) != pfn)
+		return 0;
+
+	return memblock_is_map_memory(__pfn_to_phys(pfn));
+}
+EXPORT_SYMBOL(pfn_valid);
+#endif
+
+#ifndef CONFIG_SPARSEMEM
+static void __init arm_memory_present(void)
+{
+}
+#else
+static void __init arm_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 bool arm_memblock_steal_permitted = true;
+
+phys_addr_t __init arm_memblock_steal(phys_addr_t size, phys_addr_t align)
+{
+	phys_addr_t phys;
+
+	BUG_ON(!arm_memblock_steal_permitted);
+
+	phys = memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ANYWHERE);
+	memblock_free(phys, size);
+	memblock_remove(phys, size);
+
+	return phys;
+}
+
+static void __init arm_initrd_init(void)
+{
+#ifdef CONFIG_BLK_DEV_INITRD
+	phys_addr_t start;
+	unsigned long size;
+
+	/* FDT scan will populate initrd_start */
+	if (initrd_start && !phys_initrd_size) {
+		phys_initrd_start = __virt_to_phys(initrd_start);
+		phys_initrd_size = initrd_end - initrd_start;
+	}
+
+	initrd_start = initrd_end = 0;
+
+	if (!phys_initrd_size)
+		return;
+
+	/*
+	 * Round the memory region to page boundaries as per free_initrd_mem()
+	 * This allows us to detect whether the pages overlapping the initrd
+	 * are in use, but more importantly, reserves the entire set of pages
+	 * as we don't want these pages allocated for other purposes.
+	 */
+	start = round_down(phys_initrd_start, PAGE_SIZE);
+	size = phys_initrd_size + (phys_initrd_start - start);
+	size = round_up(size, PAGE_SIZE);
+
+	if (!memblock_is_region_memory(start, size)) {
+		pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region - disabling initrd\n",
+		       (u64)start, size);
+		return;
+	}
+
+	if (memblock_is_region_reserved(start, size)) {
+		pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region - disabling initrd\n",
+		       (u64)start, size);
+		return;
+	}
+
+	memblock_reserve(start, size);
+
+	/* Now convert initrd to virtual addresses */
+	initrd_start = __phys_to_virt(phys_initrd_start);
+	initrd_end = initrd_start + phys_initrd_size;
+#endif
+}
+
+void __init arm_memblock_init(const struct machine_desc *mdesc)
+{
+	/* Register the kernel text, kernel data and initrd with memblock. */
+	memblock_reserve(__pa(KERNEL_START), KERNEL_END - KERNEL_START);
+
+	arm_initrd_init();
+
+	arm_mm_memblock_reserve();
+
+	/* reserve any platform specific memblock areas */
+	if (mdesc->reserve)
+		mdesc->reserve();
+
+	early_init_fdt_reserve_self();
+	early_init_fdt_scan_reserved_mem();
+
+	/* reserve memory for DMA contiguous allocations */
+	dma_contiguous_reserve(arm_dma_limit);
+
+	arm_memblock_steal_permitted = false;
+	memblock_dump_all();
+}
+
+void __init bootmem_init(void)
+{
+	unsigned long min, max_low, max_high;
+
+	memblock_allow_resize();
+	max_low = max_high = 0;
+
+	find_limits(&min, &max_low, &max_high);
+
+	early_memtest((phys_addr_t)min << PAGE_SHIFT,
+		      (phys_addr_t)max_low << PAGE_SHIFT);
+
+	/*
+	 * Sparsemem tries to allocate bootmem in memory_present(),
+	 * so must be done after the fixed reservations
+	 */
+	arm_memory_present();
+
+	/*
+	 * sparse_init() needs the bootmem allocator up and running.
+	 */
+	sparse_init();
+
+	/*
+	 * Now free the memory - free_area_init_node needs
+	 * the sparse mem_map arrays initialized by sparse_init()
+	 * for memmap_init_zone(), otherwise all PFNs are invalid.
+	 */
+	zone_sizes_init(min, max_low, max_high);
+
+	/*
+	 * This doesn't seem to be used by the Linux memory manager any
+	 * more, but is used by ll_rw_block.  If we can get rid of it, we
+	 * also get rid of some of the stuff above as well.
+	 */
+	min_low_pfn = min;
+	max_low_pfn = max_low;
+	max_pfn = max_high;
+}
+
+/*
+ * Poison init memory with an undefined instruction (ARM) or a branch to an
+ * undefined instruction (Thumb).
+ */
+static inline void poison_init_mem(void *s, size_t count)
+{
+	u32 *p = (u32 *)s;
+	for (; count != 0; count -= 4)
+		*p++ = 0xe7fddef0;
+}
+
+static inline void __init
+free_memmap(unsigned long start_pfn, unsigned long end_pfn)
+{
+	struct page *start_pg, *end_pg;
+	phys_addr_t 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 = PAGE_ALIGN(__pa(start_pg));
+	pgend = __pa(end_pg) & PAGE_MASK;
+
+	/*
+	 * If there are free pages between these,
+	 * free the section of the memmap array.
+	 */
+	if (pg < pgend)
+		memblock_free_early(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;
+
+	/*
+	 * This relies on each bank being in address order.
+	 * The banks are sorted previously in bootmem_init().
+	 */
+	for_each_memblock(memory, reg) {
+		start = memblock_region_memory_base_pfn(reg);
+
+#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));
+#else
+		/*
+		 * Align down here since the VM subsystem insists that the
+		 * memmap entries are valid from the bank start aligned to
+		 * MAX_ORDER_NR_PAGES.
+		 */
+		start = round_down(start, MAX_ORDER_NR_PAGES);
+#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(memblock_region_memory_end_pfn(reg),
+				 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
+}
+
+#ifdef CONFIG_HIGHMEM
+static inline void free_area_high(unsigned long pfn, unsigned long end)
+{
+	for (; pfn < end; pfn++)
+		free_highmem_page(pfn_to_page(pfn));
+}
+#endif
+
+static void __init free_highpages(void)
+{
+#ifdef CONFIG_HIGHMEM
+	unsigned long max_low = max_low_pfn;
+	struct memblock_region *mem, *res;
+
+	/* set highmem page free */
+	for_each_memblock(memory, mem) {
+		unsigned long start = memblock_region_memory_base_pfn(mem);
+		unsigned long end = memblock_region_memory_end_pfn(mem);
+
+		/* Ignore complete lowmem entries */
+		if (end <= max_low)
+			continue;
+
+		if (memblock_is_nomap(mem))
+			continue;
+
+		/* Truncate partial highmem entries */
+		if (start < max_low)
+			start = max_low;
+
+		/* Find and exclude any reserved regions */
+		for_each_memblock(reserved, res) {
+			unsigned long res_start, res_end;
+
+			res_start = memblock_region_reserved_base_pfn(res);
+			res_end = memblock_region_reserved_end_pfn(res);
+
+			if (res_end < start)
+				continue;
+			if (res_start < start)
+				res_start = start;
+			if (res_start > end)
+				res_start = end;
+			if (res_end > end)
+				res_end = end;
+			if (res_start != start)
+				free_area_high(start, res_start);
+			start = res_end;
+			if (start == end)
+				break;
+		}
+
+		/* And now free anything which remains */
+		if (start < end)
+			free_area_high(start, end);
+	}
+#endif
+}
+
+/*
+ * 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)
+{
+#ifdef CONFIG_HAVE_TCM
+	/* These pointers are filled in on TCM detection */
+	extern u32 dtcm_end;
+	extern u32 itcm_end;
+#endif
+
+	set_max_mapnr(pfn_to_page(max_pfn) - mem_map);
+
+	/* this will put all unused low memory onto the freelists */
+	free_unused_memmap();
+	free_all_bootmem();
+
+#ifdef CONFIG_SA1111
+	/* now that our DMA memory is actually so designated, we can free it */
+	free_reserved_area(__va(PHYS_OFFSET), swapper_pg_dir, -1, NULL);
+#endif
+
+	free_highpages();
+
+	mem_init_print_info(NULL);
+
+#define MLK(b, t) b, t, ((t) - (b)) >> 10
+#define MLM(b, t) b, t, ((t) - (b)) >> 20
+#define MLK_ROUNDUP(b, t) b, t, DIV_ROUND_UP(((t) - (b)), SZ_1K)
+
+	pr_notice("Virtual kernel memory layout:\n"
+			"    vector  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
+#ifdef CONFIG_HAVE_TCM
+			"    DTCM    : 0x%08lx - 0x%08lx   (%4ld kB)\n"
+			"    ITCM    : 0x%08lx - 0x%08lx   (%4ld kB)\n"
+#endif
+			"    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
+			"    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
+			"    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
+#ifdef CONFIG_HIGHMEM
+			"    pkmap   : 0x%08lx - 0x%08lx   (%4ld MB)\n"
+#endif
+#ifdef CONFIG_MODULES
+			"    modules : 0x%08lx - 0x%08lx   (%4ld MB)\n"
+#endif
+			"      .text : 0x%p" " - 0x%p" "   (%4td kB)\n"
+			"      .init : 0x%p" " - 0x%p" "   (%4td kB)\n"
+			"      .data : 0x%p" " - 0x%p" "   (%4td kB)\n"
+			"       .bss : 0x%p" " - 0x%p" "   (%4td kB)\n",
+
+			MLK(VECTORS_BASE, VECTORS_BASE + PAGE_SIZE),
+#ifdef CONFIG_HAVE_TCM
+			MLK(DTCM_OFFSET, (unsigned long) dtcm_end),
+			MLK(ITCM_OFFSET, (unsigned long) itcm_end),
+#endif
+			MLK(FIXADDR_START, FIXADDR_END),
+			MLM(VMALLOC_START, VMALLOC_END),
+			MLM(PAGE_OFFSET, (unsigned long)high_memory),
+#ifdef CONFIG_HIGHMEM
+			MLM(PKMAP_BASE, (PKMAP_BASE) + (LAST_PKMAP) *
+				(PAGE_SIZE)),
+#endif
+#ifdef CONFIG_MODULES
+			MLM(MODULES_VADDR, MODULES_END),
+#endif
+
+			MLK_ROUNDUP(_text, _etext),
+			MLK_ROUNDUP(__init_begin, __init_end),
+			MLK_ROUNDUP(_sdata, _edata),
+			MLK_ROUNDUP(__bss_start, __bss_stop));
+
+#undef MLK
+#undef MLM
+#undef MLK_ROUNDUP
+
+	/*
+	 * Check boundaries twice: Some fundamental inconsistencies can
+	 * be detected at build time already.
+	 */
+#ifdef CONFIG_MMU
+	BUILD_BUG_ON(TASK_SIZE				> MODULES_VADDR);
+	BUG_ON(TASK_SIZE 				> MODULES_VADDR);
+#endif
+
+#ifdef CONFIG_HIGHMEM
+	BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
+	BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE	> PAGE_OFFSET);
+#endif
+}
+
+#ifdef CONFIG_STRICT_KERNEL_RWX
+struct section_perm {
+	const char *name;
+	unsigned long start;
+	unsigned long end;
+	pmdval_t mask;
+	pmdval_t prot;
+	pmdval_t clear;
+};
+
+/* First section-aligned location at or after __start_rodata. */
+extern char __start_rodata_section_aligned[];
+
+static struct section_perm nx_perms[] = {
+	/* Make pages tables, etc before _stext RW (set NX). */
+	{
+		.name	= "pre-text NX",
+		.start	= PAGE_OFFSET,
+		.end	= (unsigned long)_stext,
+		.mask	= ~PMD_SECT_XN,
+		.prot	= PMD_SECT_XN,
+	},
+	/* Make init RW (set NX). */
+	{
+		.name	= "init NX",
+		.start	= (unsigned long)__init_begin,
+		.end	= (unsigned long)_sdata,
+		.mask	= ~PMD_SECT_XN,
+		.prot	= PMD_SECT_XN,
+	},
+	/* Make rodata NX (set RO in ro_perms below). */
+	{
+		.name	= "rodata NX",
+		.start  = (unsigned long)__start_rodata_section_aligned,
+		.end    = (unsigned long)__init_begin,
+		.mask   = ~PMD_SECT_XN,
+		.prot   = PMD_SECT_XN,
+	},
+};
+
+static struct section_perm ro_perms[] = {
+	/* Make kernel code and rodata RX (set RO). */
+	{
+		.name	= "text/rodata RO",
+		.start  = (unsigned long)_stext,
+		.end    = (unsigned long)__init_begin,
+#ifdef CONFIG_ARM_LPAE
+		.mask   = ~(L_PMD_SECT_RDONLY | PMD_SECT_AP2),
+		.prot   = L_PMD_SECT_RDONLY | PMD_SECT_AP2,
+#else
+		.mask   = ~(PMD_SECT_APX | PMD_SECT_AP_WRITE),
+		.prot   = PMD_SECT_APX | PMD_SECT_AP_WRITE,
+		.clear  = PMD_SECT_AP_WRITE,
+#endif
+	},
+};
+
+/*
+ * Updates section permissions only for the current mm (sections are
+ * copied into each mm). During startup, this is the init_mm. Is only
+ * safe to be called with preemption disabled, as under stop_machine().
+ */
+static inline void section_update(unsigned long addr, pmdval_t mask,
+				  pmdval_t prot, struct mm_struct *mm)
+{
+	pmd_t *pmd;
+
+	pmd = pmd_offset(pud_offset(pgd_offset(mm, addr), addr), addr);
+
+#ifdef CONFIG_ARM_LPAE
+	pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
+#else
+	if (addr & SECTION_SIZE)
+		pmd[1] = __pmd((pmd_val(pmd[1]) & mask) | prot);
+	else
+		pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
+#endif
+	flush_pmd_entry(pmd);
+	local_flush_tlb_kernel_range(addr, addr + SECTION_SIZE);
+}
+
+/* Make sure extended page tables are in use. */
+static inline bool arch_has_strict_perms(void)
+{
+	if (cpu_architecture() < CPU_ARCH_ARMv6)
+		return false;
+
+	return !!(get_cr() & CR_XP);
+}
+
+void set_section_perms(struct section_perm *perms, int n, bool set,
+			struct mm_struct *mm)
+{
+	size_t i;
+	unsigned long addr;
+
+	if (!arch_has_strict_perms())
+		return;
+
+	for (i = 0; i < n; i++) {
+		if (!IS_ALIGNED(perms[i].start, SECTION_SIZE) ||
+		    !IS_ALIGNED(perms[i].end, SECTION_SIZE)) {
+			pr_err("BUG: %s section %lx-%lx not aligned to %lx\n",
+				perms[i].name, perms[i].start, perms[i].end,
+				SECTION_SIZE);
+			continue;
+		}
+
+		for (addr = perms[i].start;
+		     addr < perms[i].end;
+		     addr += SECTION_SIZE)
+			section_update(addr, perms[i].mask,
+				set ? perms[i].prot : perms[i].clear, mm);
+	}
+
+}
+
+/**
+ * update_sections_early intended to be called only through stop_machine
+ * framework and executed by only one CPU while all other CPUs will spin and
+ * wait, so no locking is required in this function.
+ */
+static void update_sections_early(struct section_perm perms[], int n)
+{
+	struct task_struct *t, *s;
+
+	for_each_process(t) {
+		if (t->flags & PF_KTHREAD)
+			continue;
+		for_each_thread(t, s)
+			if (s->mm)
+				set_section_perms(perms, n, true, s->mm);
+	}
+	set_section_perms(perms, n, true, current->active_mm);
+	set_section_perms(perms, n, true, &init_mm);
+}
+
+static int __fix_kernmem_perms(void *unused)
+{
+	update_sections_early(nx_perms, ARRAY_SIZE(nx_perms));
+	return 0;
+}
+
+static void fix_kernmem_perms(void)
+{
+	stop_machine(__fix_kernmem_perms, NULL, NULL);
+}
+
+static int __mark_rodata_ro(void *unused)
+{
+	update_sections_early(ro_perms, ARRAY_SIZE(ro_perms));
+	return 0;
+}
+
+static int kernel_set_to_readonly __read_mostly;
+
+void mark_rodata_ro(void)
+{
+	kernel_set_to_readonly = 1;
+	stop_machine(__mark_rodata_ro, NULL, NULL);
+	debug_checkwx();
+}
+
+void set_kernel_text_rw(void)
+{
+	if (!kernel_set_to_readonly)
+		return;
+
+	set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), false,
+				current->active_mm);
+}
+
+void set_kernel_text_ro(void)
+{
+	if (!kernel_set_to_readonly)
+		return;
+
+	set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), true,
+				current->active_mm);
+}
+
+#else
+static inline void fix_kernmem_perms(void) { }
+#endif /* CONFIG_STRICT_KERNEL_RWX */
+
+void free_initmem(void)
+{
+	fix_kernmem_perms();
+
+	poison_init_mem(__init_begin, __init_end - __init_begin);
+	if (!machine_is_integrator() && !machine_is_cintegrator())
+		free_initmem_default(-1);
+}
+
+#ifdef CONFIG_BLK_DEV_INITRD
+
+static int keep_initrd;
+
+void free_initrd_mem(unsigned long start, unsigned long end)
+{
+	if (!keep_initrd) {
+		if (start == initrd_start)
+			start = round_down(start, PAGE_SIZE);
+		if (end == initrd_end)
+			end = round_up(end, PAGE_SIZE);
+
+		poison_init_mem((void *)start, PAGE_ALIGN(end) - start);
+		free_reserved_area((void *)start, (void *)end, -1, "initrd");
+	}
+}
+
+static int __init keepinitrd_setup(char *__unused)
+{
+	keep_initrd = 1;
+	return 1;
+}
+
+__setup("keepinitrd", keepinitrd_setup);
+#endif