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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /arch/arm64/mm/mmu.c
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/arm64/mm/mmu.c')
-rw-r--r--arch/arm64/mm/mmu.c1489
1 files changed, 1489 insertions, 0 deletions
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
new file mode 100644
index 0000000000..47781bec61
--- /dev/null
+++ b/arch/arm64/mm/mmu.c
@@ -0,0 +1,1489 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Based on arch/arm/mm/mmu.c
+ *
+ * Copyright (C) 1995-2005 Russell King
+ * Copyright (C) 2012 ARM Ltd.
+ */
+
+#include <linux/cache.h>
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/ioport.h>
+#include <linux/kexec.h>
+#include <linux/libfdt.h>
+#include <linux/mman.h>
+#include <linux/nodemask.h>
+#include <linux/memblock.h>
+#include <linux/memremap.h>
+#include <linux/memory.h>
+#include <linux/fs.h>
+#include <linux/io.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <linux/set_memory.h>
+#include <linux/kfence.h>
+
+#include <asm/barrier.h>
+#include <asm/cputype.h>
+#include <asm/fixmap.h>
+#include <asm/kasan.h>
+#include <asm/kernel-pgtable.h>
+#include <asm/sections.h>
+#include <asm/setup.h>
+#include <linux/sizes.h>
+#include <asm/tlb.h>
+#include <asm/mmu_context.h>
+#include <asm/ptdump.h>
+#include <asm/tlbflush.h>
+#include <asm/pgalloc.h>
+#include <asm/kfence.h>
+
+#define NO_BLOCK_MAPPINGS BIT(0)
+#define NO_CONT_MAPPINGS BIT(1)
+#define NO_EXEC_MAPPINGS BIT(2) /* assumes FEAT_HPDS is not used */
+
+int idmap_t0sz __ro_after_init;
+
+#if VA_BITS > 48
+u64 vabits_actual __ro_after_init = VA_BITS_MIN;
+EXPORT_SYMBOL(vabits_actual);
+#endif
+
+u64 kimage_vaddr __ro_after_init = (u64)&_text;
+EXPORT_SYMBOL(kimage_vaddr);
+
+u64 kimage_voffset __ro_after_init;
+EXPORT_SYMBOL(kimage_voffset);
+
+u32 __boot_cpu_mode[] = { BOOT_CPU_MODE_EL2, BOOT_CPU_MODE_EL1 };
+
+/*
+ * The booting CPU updates the failed status @__early_cpu_boot_status,
+ * with MMU turned off.
+ */
+long __section(".mmuoff.data.write") __early_cpu_boot_status;
+
+/*
+ * Empty_zero_page is a special page that is used for zero-initialized data
+ * and COW.
+ */
+unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
+EXPORT_SYMBOL(empty_zero_page);
+
+static DEFINE_SPINLOCK(swapper_pgdir_lock);
+static DEFINE_MUTEX(fixmap_lock);
+
+void set_swapper_pgd(pgd_t *pgdp, pgd_t pgd)
+{
+ pgd_t *fixmap_pgdp;
+
+ spin_lock(&swapper_pgdir_lock);
+ fixmap_pgdp = pgd_set_fixmap(__pa_symbol(pgdp));
+ WRITE_ONCE(*fixmap_pgdp, pgd);
+ /*
+ * We need dsb(ishst) here to ensure the page-table-walker sees
+ * our new entry before set_p?d() returns. The fixmap's
+ * flush_tlb_kernel_range() via clear_fixmap() does this for us.
+ */
+ pgd_clear_fixmap();
+ spin_unlock(&swapper_pgdir_lock);
+}
+
+pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
+ unsigned long size, pgprot_t vma_prot)
+{
+ if (!pfn_is_map_memory(pfn))
+ return pgprot_noncached(vma_prot);
+ else if (file->f_flags & O_SYNC)
+ return pgprot_writecombine(vma_prot);
+ return vma_prot;
+}
+EXPORT_SYMBOL(phys_mem_access_prot);
+
+static phys_addr_t __init early_pgtable_alloc(int shift)
+{
+ phys_addr_t phys;
+ void *ptr;
+
+ phys = memblock_phys_alloc_range(PAGE_SIZE, PAGE_SIZE, 0,
+ MEMBLOCK_ALLOC_NOLEAKTRACE);
+ if (!phys)
+ panic("Failed to allocate page table page\n");
+
+ /*
+ * The FIX_{PGD,PUD,PMD} slots may be in active use, but the FIX_PTE
+ * slot will be free, so we can (ab)use the FIX_PTE slot to initialise
+ * any level of table.
+ */
+ ptr = pte_set_fixmap(phys);
+
+ memset(ptr, 0, PAGE_SIZE);
+
+ /*
+ * Implicit barriers also ensure the zeroed page is visible to the page
+ * table walker
+ */
+ pte_clear_fixmap();
+
+ return phys;
+}
+
+bool pgattr_change_is_safe(u64 old, u64 new)
+{
+ /*
+ * The following mapping attributes may be updated in live
+ * kernel mappings without the need for break-before-make.
+ */
+ pteval_t mask = PTE_PXN | PTE_RDONLY | PTE_WRITE | PTE_NG;
+
+ /* creating or taking down mappings is always safe */
+ if (!pte_valid(__pte(old)) || !pte_valid(__pte(new)))
+ return true;
+
+ /* A live entry's pfn should not change */
+ if (pte_pfn(__pte(old)) != pte_pfn(__pte(new)))
+ return false;
+
+ /* live contiguous mappings may not be manipulated at all */
+ if ((old | new) & PTE_CONT)
+ return false;
+
+ /* Transitioning from Non-Global to Global is unsafe */
+ if (old & ~new & PTE_NG)
+ return false;
+
+ /*
+ * Changing the memory type between Normal and Normal-Tagged is safe
+ * since Tagged is considered a permission attribute from the
+ * mismatched attribute aliases perspective.
+ */
+ if (((old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) ||
+ (old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED)) &&
+ ((new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) ||
+ (new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED)))
+ mask |= PTE_ATTRINDX_MASK;
+
+ return ((old ^ new) & ~mask) == 0;
+}
+
+static void init_pte(pmd_t *pmdp, unsigned long addr, unsigned long end,
+ phys_addr_t phys, pgprot_t prot)
+{
+ pte_t *ptep;
+
+ ptep = pte_set_fixmap_offset(pmdp, addr);
+ do {
+ pte_t old_pte = READ_ONCE(*ptep);
+
+ set_pte(ptep, pfn_pte(__phys_to_pfn(phys), prot));
+
+ /*
+ * After the PTE entry has been populated once, we
+ * only allow updates to the permission attributes.
+ */
+ BUG_ON(!pgattr_change_is_safe(pte_val(old_pte),
+ READ_ONCE(pte_val(*ptep))));
+
+ phys += PAGE_SIZE;
+ } while (ptep++, addr += PAGE_SIZE, addr != end);
+
+ pte_clear_fixmap();
+}
+
+static void alloc_init_cont_pte(pmd_t *pmdp, unsigned long addr,
+ unsigned long end, phys_addr_t phys,
+ pgprot_t prot,
+ phys_addr_t (*pgtable_alloc)(int),
+ int flags)
+{
+ unsigned long next;
+ pmd_t pmd = READ_ONCE(*pmdp);
+
+ BUG_ON(pmd_sect(pmd));
+ if (pmd_none(pmd)) {
+ pmdval_t pmdval = PMD_TYPE_TABLE | PMD_TABLE_UXN;
+ phys_addr_t pte_phys;
+
+ if (flags & NO_EXEC_MAPPINGS)
+ pmdval |= PMD_TABLE_PXN;
+ BUG_ON(!pgtable_alloc);
+ pte_phys = pgtable_alloc(PAGE_SHIFT);
+ __pmd_populate(pmdp, pte_phys, pmdval);
+ pmd = READ_ONCE(*pmdp);
+ }
+ BUG_ON(pmd_bad(pmd));
+
+ do {
+ pgprot_t __prot = prot;
+
+ next = pte_cont_addr_end(addr, end);
+
+ /* use a contiguous mapping if the range is suitably aligned */
+ if ((((addr | next | phys) & ~CONT_PTE_MASK) == 0) &&
+ (flags & NO_CONT_MAPPINGS) == 0)
+ __prot = __pgprot(pgprot_val(prot) | PTE_CONT);
+
+ init_pte(pmdp, addr, next, phys, __prot);
+
+ phys += next - addr;
+ } while (addr = next, addr != end);
+}
+
+static void init_pmd(pud_t *pudp, unsigned long addr, unsigned long end,
+ phys_addr_t phys, pgprot_t prot,
+ phys_addr_t (*pgtable_alloc)(int), int flags)
+{
+ unsigned long next;
+ pmd_t *pmdp;
+
+ pmdp = pmd_set_fixmap_offset(pudp, addr);
+ do {
+ pmd_t old_pmd = READ_ONCE(*pmdp);
+
+ next = pmd_addr_end(addr, end);
+
+ /* try section mapping first */
+ if (((addr | next | phys) & ~PMD_MASK) == 0 &&
+ (flags & NO_BLOCK_MAPPINGS) == 0) {
+ pmd_set_huge(pmdp, phys, prot);
+
+ /*
+ * After the PMD entry has been populated once, we
+ * only allow updates to the permission attributes.
+ */
+ BUG_ON(!pgattr_change_is_safe(pmd_val(old_pmd),
+ READ_ONCE(pmd_val(*pmdp))));
+ } else {
+ alloc_init_cont_pte(pmdp, addr, next, phys, prot,
+ pgtable_alloc, flags);
+
+ BUG_ON(pmd_val(old_pmd) != 0 &&
+ pmd_val(old_pmd) != READ_ONCE(pmd_val(*pmdp)));
+ }
+ phys += next - addr;
+ } while (pmdp++, addr = next, addr != end);
+
+ pmd_clear_fixmap();
+}
+
+static void alloc_init_cont_pmd(pud_t *pudp, unsigned long addr,
+ unsigned long end, phys_addr_t phys,
+ pgprot_t prot,
+ phys_addr_t (*pgtable_alloc)(int), int flags)
+{
+ unsigned long next;
+ pud_t pud = READ_ONCE(*pudp);
+
+ /*
+ * Check for initial section mappings in the pgd/pud.
+ */
+ BUG_ON(pud_sect(pud));
+ if (pud_none(pud)) {
+ pudval_t pudval = PUD_TYPE_TABLE | PUD_TABLE_UXN;
+ phys_addr_t pmd_phys;
+
+ if (flags & NO_EXEC_MAPPINGS)
+ pudval |= PUD_TABLE_PXN;
+ BUG_ON(!pgtable_alloc);
+ pmd_phys = pgtable_alloc(PMD_SHIFT);
+ __pud_populate(pudp, pmd_phys, pudval);
+ pud = READ_ONCE(*pudp);
+ }
+ BUG_ON(pud_bad(pud));
+
+ do {
+ pgprot_t __prot = prot;
+
+ next = pmd_cont_addr_end(addr, end);
+
+ /* use a contiguous mapping if the range is suitably aligned */
+ if ((((addr | next | phys) & ~CONT_PMD_MASK) == 0) &&
+ (flags & NO_CONT_MAPPINGS) == 0)
+ __prot = __pgprot(pgprot_val(prot) | PTE_CONT);
+
+ init_pmd(pudp, addr, next, phys, __prot, pgtable_alloc, flags);
+
+ phys += next - addr;
+ } while (addr = next, addr != end);
+}
+
+static void alloc_init_pud(pgd_t *pgdp, unsigned long addr, unsigned long end,
+ phys_addr_t phys, pgprot_t prot,
+ phys_addr_t (*pgtable_alloc)(int),
+ int flags)
+{
+ unsigned long next;
+ pud_t *pudp;
+ p4d_t *p4dp = p4d_offset(pgdp, addr);
+ p4d_t p4d = READ_ONCE(*p4dp);
+
+ if (p4d_none(p4d)) {
+ p4dval_t p4dval = P4D_TYPE_TABLE | P4D_TABLE_UXN;
+ phys_addr_t pud_phys;
+
+ if (flags & NO_EXEC_MAPPINGS)
+ p4dval |= P4D_TABLE_PXN;
+ BUG_ON(!pgtable_alloc);
+ pud_phys = pgtable_alloc(PUD_SHIFT);
+ __p4d_populate(p4dp, pud_phys, p4dval);
+ p4d = READ_ONCE(*p4dp);
+ }
+ BUG_ON(p4d_bad(p4d));
+
+ pudp = pud_set_fixmap_offset(p4dp, addr);
+ do {
+ pud_t old_pud = READ_ONCE(*pudp);
+
+ next = pud_addr_end(addr, end);
+
+ /*
+ * For 4K granule only, attempt to put down a 1GB block
+ */
+ if (pud_sect_supported() &&
+ ((addr | next | phys) & ~PUD_MASK) == 0 &&
+ (flags & NO_BLOCK_MAPPINGS) == 0) {
+ pud_set_huge(pudp, phys, prot);
+
+ /*
+ * After the PUD entry has been populated once, we
+ * only allow updates to the permission attributes.
+ */
+ BUG_ON(!pgattr_change_is_safe(pud_val(old_pud),
+ READ_ONCE(pud_val(*pudp))));
+ } else {
+ alloc_init_cont_pmd(pudp, addr, next, phys, prot,
+ pgtable_alloc, flags);
+
+ BUG_ON(pud_val(old_pud) != 0 &&
+ pud_val(old_pud) != READ_ONCE(pud_val(*pudp)));
+ }
+ phys += next - addr;
+ } while (pudp++, addr = next, addr != end);
+
+ pud_clear_fixmap();
+}
+
+static void __create_pgd_mapping_locked(pgd_t *pgdir, phys_addr_t phys,
+ unsigned long virt, phys_addr_t size,
+ pgprot_t prot,
+ phys_addr_t (*pgtable_alloc)(int),
+ int flags)
+{
+ unsigned long addr, end, next;
+ pgd_t *pgdp = pgd_offset_pgd(pgdir, virt);
+
+ /*
+ * If the virtual and physical address don't have the same offset
+ * within a page, we cannot map the region as the caller expects.
+ */
+ if (WARN_ON((phys ^ virt) & ~PAGE_MASK))
+ return;
+
+ phys &= PAGE_MASK;
+ addr = virt & PAGE_MASK;
+ end = PAGE_ALIGN(virt + size);
+
+ do {
+ next = pgd_addr_end(addr, end);
+ alloc_init_pud(pgdp, addr, next, phys, prot, pgtable_alloc,
+ flags);
+ phys += next - addr;
+ } while (pgdp++, addr = next, addr != end);
+}
+
+static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
+ unsigned long virt, phys_addr_t size,
+ pgprot_t prot,
+ phys_addr_t (*pgtable_alloc)(int),
+ int flags)
+{
+ mutex_lock(&fixmap_lock);
+ __create_pgd_mapping_locked(pgdir, phys, virt, size, prot,
+ pgtable_alloc, flags);
+ mutex_unlock(&fixmap_lock);
+}
+
+#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
+extern __alias(__create_pgd_mapping_locked)
+void create_kpti_ng_temp_pgd(pgd_t *pgdir, phys_addr_t phys, unsigned long virt,
+ phys_addr_t size, pgprot_t prot,
+ phys_addr_t (*pgtable_alloc)(int), int flags);
+#endif
+
+static phys_addr_t __pgd_pgtable_alloc(int shift)
+{
+ void *ptr = (void *)__get_free_page(GFP_PGTABLE_KERNEL);
+ BUG_ON(!ptr);
+
+ /* Ensure the zeroed page is visible to the page table walker */
+ dsb(ishst);
+ return __pa(ptr);
+}
+
+static phys_addr_t pgd_pgtable_alloc(int shift)
+{
+ phys_addr_t pa = __pgd_pgtable_alloc(shift);
+ struct ptdesc *ptdesc = page_ptdesc(phys_to_page(pa));
+
+ /*
+ * Call proper page table ctor in case later we need to
+ * call core mm functions like apply_to_page_range() on
+ * this pre-allocated page table.
+ *
+ * We don't select ARCH_ENABLE_SPLIT_PMD_PTLOCK if pmd is
+ * folded, and if so pagetable_pte_ctor() becomes nop.
+ */
+ if (shift == PAGE_SHIFT)
+ BUG_ON(!pagetable_pte_ctor(ptdesc));
+ else if (shift == PMD_SHIFT)
+ BUG_ON(!pagetable_pmd_ctor(ptdesc));
+
+ return pa;
+}
+
+/*
+ * This function can only be used to modify existing table entries,
+ * without allocating new levels of table. Note that this permits the
+ * creation of new section or page entries.
+ */
+void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt,
+ phys_addr_t size, pgprot_t prot)
+{
+ if (virt < PAGE_OFFSET) {
+ pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
+ &phys, virt);
+ return;
+ }
+ __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL,
+ NO_CONT_MAPPINGS);
+}
+
+void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
+ unsigned long virt, phys_addr_t size,
+ pgprot_t prot, bool page_mappings_only)
+{
+ int flags = 0;
+
+ BUG_ON(mm == &init_mm);
+
+ if (page_mappings_only)
+ flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
+
+ __create_pgd_mapping(mm->pgd, phys, virt, size, prot,
+ pgd_pgtable_alloc, flags);
+}
+
+static void update_mapping_prot(phys_addr_t phys, unsigned long virt,
+ phys_addr_t size, pgprot_t prot)
+{
+ if (virt < PAGE_OFFSET) {
+ pr_warn("BUG: not updating mapping for %pa at 0x%016lx - outside kernel range\n",
+ &phys, virt);
+ return;
+ }
+
+ __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL,
+ NO_CONT_MAPPINGS);
+
+ /* flush the TLBs after updating live kernel mappings */
+ flush_tlb_kernel_range(virt, virt + size);
+}
+
+static void __init __map_memblock(pgd_t *pgdp, phys_addr_t start,
+ phys_addr_t end, pgprot_t prot, int flags)
+{
+ __create_pgd_mapping(pgdp, start, __phys_to_virt(start), end - start,
+ prot, early_pgtable_alloc, flags);
+}
+
+void __init mark_linear_text_alias_ro(void)
+{
+ /*
+ * Remove the write permissions from the linear alias of .text/.rodata
+ */
+ update_mapping_prot(__pa_symbol(_stext), (unsigned long)lm_alias(_stext),
+ (unsigned long)__init_begin - (unsigned long)_stext,
+ PAGE_KERNEL_RO);
+}
+
+#ifdef CONFIG_KFENCE
+
+bool __ro_after_init kfence_early_init = !!CONFIG_KFENCE_SAMPLE_INTERVAL;
+
+/* early_param() will be parsed before map_mem() below. */
+static int __init parse_kfence_early_init(char *arg)
+{
+ int val;
+
+ if (get_option(&arg, &val))
+ kfence_early_init = !!val;
+ return 0;
+}
+early_param("kfence.sample_interval", parse_kfence_early_init);
+
+static phys_addr_t __init arm64_kfence_alloc_pool(void)
+{
+ phys_addr_t kfence_pool;
+
+ if (!kfence_early_init)
+ return 0;
+
+ kfence_pool = memblock_phys_alloc(KFENCE_POOL_SIZE, PAGE_SIZE);
+ if (!kfence_pool) {
+ pr_err("failed to allocate kfence pool\n");
+ kfence_early_init = false;
+ return 0;
+ }
+
+ /* Temporarily mark as NOMAP. */
+ memblock_mark_nomap(kfence_pool, KFENCE_POOL_SIZE);
+
+ return kfence_pool;
+}
+
+static void __init arm64_kfence_map_pool(phys_addr_t kfence_pool, pgd_t *pgdp)
+{
+ if (!kfence_pool)
+ return;
+
+ /* KFENCE pool needs page-level mapping. */
+ __map_memblock(pgdp, kfence_pool, kfence_pool + KFENCE_POOL_SIZE,
+ pgprot_tagged(PAGE_KERNEL),
+ NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS);
+ memblock_clear_nomap(kfence_pool, KFENCE_POOL_SIZE);
+ __kfence_pool = phys_to_virt(kfence_pool);
+}
+#else /* CONFIG_KFENCE */
+
+static inline phys_addr_t arm64_kfence_alloc_pool(void) { return 0; }
+static inline void arm64_kfence_map_pool(phys_addr_t kfence_pool, pgd_t *pgdp) { }
+
+#endif /* CONFIG_KFENCE */
+
+static void __init map_mem(pgd_t *pgdp)
+{
+ static const u64 direct_map_end = _PAGE_END(VA_BITS_MIN);
+ phys_addr_t kernel_start = __pa_symbol(_stext);
+ phys_addr_t kernel_end = __pa_symbol(__init_begin);
+ phys_addr_t start, end;
+ phys_addr_t early_kfence_pool;
+ int flags = NO_EXEC_MAPPINGS;
+ u64 i;
+
+ /*
+ * Setting hierarchical PXNTable attributes on table entries covering
+ * the linear region is only possible if it is guaranteed that no table
+ * entries at any level are being shared between the linear region and
+ * the vmalloc region. Check whether this is true for the PGD level, in
+ * which case it is guaranteed to be true for all other levels as well.
+ */
+ BUILD_BUG_ON(pgd_index(direct_map_end - 1) == pgd_index(direct_map_end));
+
+ early_kfence_pool = arm64_kfence_alloc_pool();
+
+ if (can_set_direct_map())
+ flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
+
+ /*
+ * Take care not to create a writable alias for the
+ * read-only text and rodata sections of the kernel image.
+ * So temporarily mark them as NOMAP to skip mappings in
+ * the following for-loop
+ */
+ memblock_mark_nomap(kernel_start, kernel_end - kernel_start);
+
+ /* map all the memory banks */
+ for_each_mem_range(i, &start, &end) {
+ if (start >= end)
+ break;
+ /*
+ * The linear map must allow allocation tags reading/writing
+ * if MTE is present. Otherwise, it has the same attributes as
+ * PAGE_KERNEL.
+ */
+ __map_memblock(pgdp, start, end, pgprot_tagged(PAGE_KERNEL),
+ flags);
+ }
+
+ /*
+ * Map the linear alias of the [_stext, __init_begin) interval
+ * as non-executable now, and remove the write permission in
+ * mark_linear_text_alias_ro() below (which will be called after
+ * alternative patching has completed). This makes the contents
+ * of the region accessible to subsystems such as hibernate,
+ * but protects it from inadvertent modification or execution.
+ * Note that contiguous mappings cannot be remapped in this way,
+ * so we should avoid them here.
+ */
+ __map_memblock(pgdp, kernel_start, kernel_end,
+ PAGE_KERNEL, NO_CONT_MAPPINGS);
+ memblock_clear_nomap(kernel_start, kernel_end - kernel_start);
+ arm64_kfence_map_pool(early_kfence_pool, pgdp);
+}
+
+void mark_rodata_ro(void)
+{
+ unsigned long section_size;
+
+ /*
+ * mark .rodata as read only. Use __init_begin rather than __end_rodata
+ * to cover NOTES and EXCEPTION_TABLE.
+ */
+ section_size = (unsigned long)__init_begin - (unsigned long)__start_rodata;
+ update_mapping_prot(__pa_symbol(__start_rodata), (unsigned long)__start_rodata,
+ section_size, PAGE_KERNEL_RO);
+
+ debug_checkwx();
+}
+
+static void __init map_kernel_segment(pgd_t *pgdp, void *va_start, void *va_end,
+ pgprot_t prot, struct vm_struct *vma,
+ int flags, unsigned long vm_flags)
+{
+ phys_addr_t pa_start = __pa_symbol(va_start);
+ unsigned long size = va_end - va_start;
+
+ BUG_ON(!PAGE_ALIGNED(pa_start));
+ BUG_ON(!PAGE_ALIGNED(size));
+
+ __create_pgd_mapping(pgdp, pa_start, (unsigned long)va_start, size, prot,
+ early_pgtable_alloc, flags);
+
+ if (!(vm_flags & VM_NO_GUARD))
+ size += PAGE_SIZE;
+
+ vma->addr = va_start;
+ vma->phys_addr = pa_start;
+ vma->size = size;
+ vma->flags = VM_MAP | vm_flags;
+ vma->caller = __builtin_return_address(0);
+
+ vm_area_add_early(vma);
+}
+
+static pgprot_t kernel_exec_prot(void)
+{
+ return rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;
+}
+
+#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
+static int __init map_entry_trampoline(void)
+{
+ int i;
+
+ pgprot_t prot = kernel_exec_prot();
+ phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start);
+
+ /* The trampoline is always mapped and can therefore be global */
+ pgprot_val(prot) &= ~PTE_NG;
+
+ /* Map only the text into the trampoline page table */
+ memset(tramp_pg_dir, 0, PGD_SIZE);
+ __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS,
+ entry_tramp_text_size(), prot,
+ __pgd_pgtable_alloc, NO_BLOCK_MAPPINGS);
+
+ /* Map both the text and data into the kernel page table */
+ for (i = 0; i < DIV_ROUND_UP(entry_tramp_text_size(), PAGE_SIZE); i++)
+ __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i,
+ pa_start + i * PAGE_SIZE, prot);
+
+ if (IS_ENABLED(CONFIG_RELOCATABLE))
+ __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i,
+ pa_start + i * PAGE_SIZE, PAGE_KERNEL_RO);
+
+ return 0;
+}
+core_initcall(map_entry_trampoline);
+#endif
+
+/*
+ * Open coded check for BTI, only for use to determine configuration
+ * for early mappings for before the cpufeature code has run.
+ */
+static bool arm64_early_this_cpu_has_bti(void)
+{
+ u64 pfr1;
+
+ if (!IS_ENABLED(CONFIG_ARM64_BTI_KERNEL))
+ return false;
+
+ pfr1 = __read_sysreg_by_encoding(SYS_ID_AA64PFR1_EL1);
+ return cpuid_feature_extract_unsigned_field(pfr1,
+ ID_AA64PFR1_EL1_BT_SHIFT);
+}
+
+/*
+ * Create fine-grained mappings for the kernel.
+ */
+static void __init map_kernel(pgd_t *pgdp)
+{
+ static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_inittext,
+ vmlinux_initdata, vmlinux_data;
+
+ /*
+ * External debuggers may need to write directly to the text
+ * mapping to install SW breakpoints. Allow this (only) when
+ * explicitly requested with rodata=off.
+ */
+ pgprot_t text_prot = kernel_exec_prot();
+
+ /*
+ * If we have a CPU that supports BTI and a kernel built for
+ * BTI then mark the kernel executable text as guarded pages
+ * now so we don't have to rewrite the page tables later.
+ */
+ if (arm64_early_this_cpu_has_bti())
+ text_prot = __pgprot_modify(text_prot, PTE_GP, PTE_GP);
+
+ /*
+ * Only rodata will be remapped with different permissions later on,
+ * all other segments are allowed to use contiguous mappings.
+ */
+ map_kernel_segment(pgdp, _stext, _etext, text_prot, &vmlinux_text, 0,
+ VM_NO_GUARD);
+ map_kernel_segment(pgdp, __start_rodata, __inittext_begin, PAGE_KERNEL,
+ &vmlinux_rodata, NO_CONT_MAPPINGS, VM_NO_GUARD);
+ map_kernel_segment(pgdp, __inittext_begin, __inittext_end, text_prot,
+ &vmlinux_inittext, 0, VM_NO_GUARD);
+ map_kernel_segment(pgdp, __initdata_begin, __initdata_end, PAGE_KERNEL,
+ &vmlinux_initdata, 0, VM_NO_GUARD);
+ map_kernel_segment(pgdp, _data, _end, PAGE_KERNEL, &vmlinux_data, 0, 0);
+
+ fixmap_copy(pgdp);
+ kasan_copy_shadow(pgdp);
+}
+
+static void __init create_idmap(void)
+{
+ u64 start = __pa_symbol(__idmap_text_start);
+ u64 size = __pa_symbol(__idmap_text_end) - start;
+ pgd_t *pgd = idmap_pg_dir;
+ u64 pgd_phys;
+
+ /* check if we need an additional level of translation */
+ if (VA_BITS < 48 && idmap_t0sz < (64 - VA_BITS_MIN)) {
+ pgd_phys = early_pgtable_alloc(PAGE_SHIFT);
+ set_pgd(&idmap_pg_dir[start >> VA_BITS],
+ __pgd(pgd_phys | P4D_TYPE_TABLE));
+ pgd = __va(pgd_phys);
+ }
+ __create_pgd_mapping(pgd, start, start, size, PAGE_KERNEL_ROX,
+ early_pgtable_alloc, 0);
+
+ if (IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0)) {
+ extern u32 __idmap_kpti_flag;
+ u64 pa = __pa_symbol(&__idmap_kpti_flag);
+
+ /*
+ * The KPTI G-to-nG conversion code needs a read-write mapping
+ * of its synchronization flag in the ID map.
+ */
+ __create_pgd_mapping(pgd, pa, pa, sizeof(u32), PAGE_KERNEL,
+ early_pgtable_alloc, 0);
+ }
+}
+
+void __init paging_init(void)
+{
+ pgd_t *pgdp = pgd_set_fixmap(__pa_symbol(swapper_pg_dir));
+ extern pgd_t init_idmap_pg_dir[];
+
+ idmap_t0sz = 63UL - __fls(__pa_symbol(_end) | GENMASK(VA_BITS_MIN - 1, 0));
+
+ map_kernel(pgdp);
+ map_mem(pgdp);
+
+ pgd_clear_fixmap();
+
+ cpu_replace_ttbr1(lm_alias(swapper_pg_dir), init_idmap_pg_dir);
+ init_mm.pgd = swapper_pg_dir;
+
+ memblock_phys_free(__pa_symbol(init_pg_dir),
+ __pa_symbol(init_pg_end) - __pa_symbol(init_pg_dir));
+
+ memblock_allow_resize();
+
+ create_idmap();
+}
+
+#ifdef CONFIG_MEMORY_HOTPLUG
+static void free_hotplug_page_range(struct page *page, size_t size,
+ struct vmem_altmap *altmap)
+{
+ if (altmap) {
+ vmem_altmap_free(altmap, size >> PAGE_SHIFT);
+ } else {
+ WARN_ON(PageReserved(page));
+ free_pages((unsigned long)page_address(page), get_order(size));
+ }
+}
+
+static void free_hotplug_pgtable_page(struct page *page)
+{
+ free_hotplug_page_range(page, PAGE_SIZE, NULL);
+}
+
+static bool pgtable_range_aligned(unsigned long start, unsigned long end,
+ unsigned long floor, unsigned long ceiling,
+ unsigned long mask)
+{
+ start &= mask;
+ if (start < floor)
+ return false;
+
+ if (ceiling) {
+ ceiling &= mask;
+ if (!ceiling)
+ return false;
+ }
+
+ if (end - 1 > ceiling - 1)
+ return false;
+ return true;
+}
+
+static void unmap_hotplug_pte_range(pmd_t *pmdp, unsigned long addr,
+ unsigned long end, bool free_mapped,
+ struct vmem_altmap *altmap)
+{
+ pte_t *ptep, pte;
+
+ do {
+ ptep = pte_offset_kernel(pmdp, addr);
+ pte = READ_ONCE(*ptep);
+ if (pte_none(pte))
+ continue;
+
+ WARN_ON(!pte_present(pte));
+ pte_clear(&init_mm, addr, ptep);
+ flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
+ if (free_mapped)
+ free_hotplug_page_range(pte_page(pte),
+ PAGE_SIZE, altmap);
+ } while (addr += PAGE_SIZE, addr < end);
+}
+
+static void unmap_hotplug_pmd_range(pud_t *pudp, unsigned long addr,
+ unsigned long end, bool free_mapped,
+ struct vmem_altmap *altmap)
+{
+ unsigned long next;
+ pmd_t *pmdp, pmd;
+
+ do {
+ next = pmd_addr_end(addr, end);
+ pmdp = pmd_offset(pudp, addr);
+ pmd = READ_ONCE(*pmdp);
+ if (pmd_none(pmd))
+ continue;
+
+ WARN_ON(!pmd_present(pmd));
+ if (pmd_sect(pmd)) {
+ pmd_clear(pmdp);
+
+ /*
+ * One TLBI should be sufficient here as the PMD_SIZE
+ * range is mapped with a single block entry.
+ */
+ flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
+ if (free_mapped)
+ free_hotplug_page_range(pmd_page(pmd),
+ PMD_SIZE, altmap);
+ continue;
+ }
+ WARN_ON(!pmd_table(pmd));
+ unmap_hotplug_pte_range(pmdp, addr, next, free_mapped, altmap);
+ } while (addr = next, addr < end);
+}
+
+static void unmap_hotplug_pud_range(p4d_t *p4dp, unsigned long addr,
+ unsigned long end, bool free_mapped,
+ struct vmem_altmap *altmap)
+{
+ unsigned long next;
+ pud_t *pudp, pud;
+
+ do {
+ next = pud_addr_end(addr, end);
+ pudp = pud_offset(p4dp, addr);
+ pud = READ_ONCE(*pudp);
+ if (pud_none(pud))
+ continue;
+
+ WARN_ON(!pud_present(pud));
+ if (pud_sect(pud)) {
+ pud_clear(pudp);
+
+ /*
+ * One TLBI should be sufficient here as the PUD_SIZE
+ * range is mapped with a single block entry.
+ */
+ flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
+ if (free_mapped)
+ free_hotplug_page_range(pud_page(pud),
+ PUD_SIZE, altmap);
+ continue;
+ }
+ WARN_ON(!pud_table(pud));
+ unmap_hotplug_pmd_range(pudp, addr, next, free_mapped, altmap);
+ } while (addr = next, addr < end);
+}
+
+static void unmap_hotplug_p4d_range(pgd_t *pgdp, unsigned long addr,
+ unsigned long end, bool free_mapped,
+ struct vmem_altmap *altmap)
+{
+ unsigned long next;
+ p4d_t *p4dp, p4d;
+
+ do {
+ next = p4d_addr_end(addr, end);
+ p4dp = p4d_offset(pgdp, addr);
+ p4d = READ_ONCE(*p4dp);
+ if (p4d_none(p4d))
+ continue;
+
+ WARN_ON(!p4d_present(p4d));
+ unmap_hotplug_pud_range(p4dp, addr, next, free_mapped, altmap);
+ } while (addr = next, addr < end);
+}
+
+static void unmap_hotplug_range(unsigned long addr, unsigned long end,
+ bool free_mapped, struct vmem_altmap *altmap)
+{
+ unsigned long next;
+ pgd_t *pgdp, pgd;
+
+ /*
+ * altmap can only be used as vmemmap mapping backing memory.
+ * In case the backing memory itself is not being freed, then
+ * altmap is irrelevant. Warn about this inconsistency when
+ * encountered.
+ */
+ WARN_ON(!free_mapped && altmap);
+
+ do {
+ next = pgd_addr_end(addr, end);
+ pgdp = pgd_offset_k(addr);
+ pgd = READ_ONCE(*pgdp);
+ if (pgd_none(pgd))
+ continue;
+
+ WARN_ON(!pgd_present(pgd));
+ unmap_hotplug_p4d_range(pgdp, addr, next, free_mapped, altmap);
+ } while (addr = next, addr < end);
+}
+
+static void free_empty_pte_table(pmd_t *pmdp, unsigned long addr,
+ unsigned long end, unsigned long floor,
+ unsigned long ceiling)
+{
+ pte_t *ptep, pte;
+ unsigned long i, start = addr;
+
+ do {
+ ptep = pte_offset_kernel(pmdp, addr);
+ pte = READ_ONCE(*ptep);
+
+ /*
+ * This is just a sanity check here which verifies that
+ * pte clearing has been done by earlier unmap loops.
+ */
+ WARN_ON(!pte_none(pte));
+ } while (addr += PAGE_SIZE, addr < end);
+
+ if (!pgtable_range_aligned(start, end, floor, ceiling, PMD_MASK))
+ return;
+
+ /*
+ * Check whether we can free the pte page if the rest of the
+ * entries are empty. Overlap with other regions have been
+ * handled by the floor/ceiling check.
+ */
+ ptep = pte_offset_kernel(pmdp, 0UL);
+ for (i = 0; i < PTRS_PER_PTE; i++) {
+ if (!pte_none(READ_ONCE(ptep[i])))
+ return;
+ }
+
+ pmd_clear(pmdp);
+ __flush_tlb_kernel_pgtable(start);
+ free_hotplug_pgtable_page(virt_to_page(ptep));
+}
+
+static void free_empty_pmd_table(pud_t *pudp, unsigned long addr,
+ unsigned long end, unsigned long floor,
+ unsigned long ceiling)
+{
+ pmd_t *pmdp, pmd;
+ unsigned long i, next, start = addr;
+
+ do {
+ next = pmd_addr_end(addr, end);
+ pmdp = pmd_offset(pudp, addr);
+ pmd = READ_ONCE(*pmdp);
+ if (pmd_none(pmd))
+ continue;
+
+ WARN_ON(!pmd_present(pmd) || !pmd_table(pmd) || pmd_sect(pmd));
+ free_empty_pte_table(pmdp, addr, next, floor, ceiling);
+ } while (addr = next, addr < end);
+
+ if (CONFIG_PGTABLE_LEVELS <= 2)
+ return;
+
+ if (!pgtable_range_aligned(start, end, floor, ceiling, PUD_MASK))
+ return;
+
+ /*
+ * Check whether we can free the pmd page if the rest of the
+ * entries are empty. Overlap with other regions have been
+ * handled by the floor/ceiling check.
+ */
+ pmdp = pmd_offset(pudp, 0UL);
+ for (i = 0; i < PTRS_PER_PMD; i++) {
+ if (!pmd_none(READ_ONCE(pmdp[i])))
+ return;
+ }
+
+ pud_clear(pudp);
+ __flush_tlb_kernel_pgtable(start);
+ free_hotplug_pgtable_page(virt_to_page(pmdp));
+}
+
+static void free_empty_pud_table(p4d_t *p4dp, unsigned long addr,
+ unsigned long end, unsigned long floor,
+ unsigned long ceiling)
+{
+ pud_t *pudp, pud;
+ unsigned long i, next, start = addr;
+
+ do {
+ next = pud_addr_end(addr, end);
+ pudp = pud_offset(p4dp, addr);
+ pud = READ_ONCE(*pudp);
+ if (pud_none(pud))
+ continue;
+
+ WARN_ON(!pud_present(pud) || !pud_table(pud) || pud_sect(pud));
+ free_empty_pmd_table(pudp, addr, next, floor, ceiling);
+ } while (addr = next, addr < end);
+
+ if (CONFIG_PGTABLE_LEVELS <= 3)
+ return;
+
+ if (!pgtable_range_aligned(start, end, floor, ceiling, PGDIR_MASK))
+ return;
+
+ /*
+ * Check whether we can free the pud page if the rest of the
+ * entries are empty. Overlap with other regions have been
+ * handled by the floor/ceiling check.
+ */
+ pudp = pud_offset(p4dp, 0UL);
+ for (i = 0; i < PTRS_PER_PUD; i++) {
+ if (!pud_none(READ_ONCE(pudp[i])))
+ return;
+ }
+
+ p4d_clear(p4dp);
+ __flush_tlb_kernel_pgtable(start);
+ free_hotplug_pgtable_page(virt_to_page(pudp));
+}
+
+static void free_empty_p4d_table(pgd_t *pgdp, unsigned long addr,
+ unsigned long end, unsigned long floor,
+ unsigned long ceiling)
+{
+ unsigned long next;
+ p4d_t *p4dp, p4d;
+
+ do {
+ next = p4d_addr_end(addr, end);
+ p4dp = p4d_offset(pgdp, addr);
+ p4d = READ_ONCE(*p4dp);
+ if (p4d_none(p4d))
+ continue;
+
+ WARN_ON(!p4d_present(p4d));
+ free_empty_pud_table(p4dp, addr, next, floor, ceiling);
+ } while (addr = next, addr < end);
+}
+
+static void free_empty_tables(unsigned long addr, unsigned long end,
+ unsigned long floor, unsigned long ceiling)
+{
+ unsigned long next;
+ pgd_t *pgdp, pgd;
+
+ do {
+ next = pgd_addr_end(addr, end);
+ pgdp = pgd_offset_k(addr);
+ pgd = READ_ONCE(*pgdp);
+ if (pgd_none(pgd))
+ continue;
+
+ WARN_ON(!pgd_present(pgd));
+ free_empty_p4d_table(pgdp, addr, next, floor, ceiling);
+ } while (addr = next, addr < end);
+}
+#endif
+
+void __meminit vmemmap_set_pmd(pmd_t *pmdp, void *p, int node,
+ unsigned long addr, unsigned long next)
+{
+ pmd_set_huge(pmdp, __pa(p), __pgprot(PROT_SECT_NORMAL));
+}
+
+int __meminit vmemmap_check_pmd(pmd_t *pmdp, int node,
+ unsigned long addr, unsigned long next)
+{
+ vmemmap_verify((pte_t *)pmdp, node, addr, next);
+ return 1;
+}
+
+int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
+ struct vmem_altmap *altmap)
+{
+ WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END));
+
+ if (!IS_ENABLED(CONFIG_ARM64_4K_PAGES))
+ return vmemmap_populate_basepages(start, end, node, altmap);
+ else
+ return vmemmap_populate_hugepages(start, end, node, altmap);
+}
+
+#ifdef CONFIG_MEMORY_HOTPLUG
+void vmemmap_free(unsigned long start, unsigned long end,
+ struct vmem_altmap *altmap)
+{
+ WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END));
+
+ unmap_hotplug_range(start, end, true, altmap);
+ free_empty_tables(start, end, VMEMMAP_START, VMEMMAP_END);
+}
+#endif /* CONFIG_MEMORY_HOTPLUG */
+
+int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot)
+{
+ pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot));
+
+ /* Only allow permission changes for now */
+ if (!pgattr_change_is_safe(READ_ONCE(pud_val(*pudp)),
+ pud_val(new_pud)))
+ return 0;
+
+ VM_BUG_ON(phys & ~PUD_MASK);
+ set_pud(pudp, new_pud);
+ return 1;
+}
+
+int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot)
+{
+ pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), mk_pmd_sect_prot(prot));
+
+ /* Only allow permission changes for now */
+ if (!pgattr_change_is_safe(READ_ONCE(pmd_val(*pmdp)),
+ pmd_val(new_pmd)))
+ return 0;
+
+ VM_BUG_ON(phys & ~PMD_MASK);
+ set_pmd(pmdp, new_pmd);
+ return 1;
+}
+
+int pud_clear_huge(pud_t *pudp)
+{
+ if (!pud_sect(READ_ONCE(*pudp)))
+ return 0;
+ pud_clear(pudp);
+ return 1;
+}
+
+int pmd_clear_huge(pmd_t *pmdp)
+{
+ if (!pmd_sect(READ_ONCE(*pmdp)))
+ return 0;
+ pmd_clear(pmdp);
+ return 1;
+}
+
+int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr)
+{
+ pte_t *table;
+ pmd_t pmd;
+
+ pmd = READ_ONCE(*pmdp);
+
+ if (!pmd_table(pmd)) {
+ VM_WARN_ON(1);
+ return 1;
+ }
+
+ table = pte_offset_kernel(pmdp, addr);
+ pmd_clear(pmdp);
+ __flush_tlb_kernel_pgtable(addr);
+ pte_free_kernel(NULL, table);
+ return 1;
+}
+
+int pud_free_pmd_page(pud_t *pudp, unsigned long addr)
+{
+ pmd_t *table;
+ pmd_t *pmdp;
+ pud_t pud;
+ unsigned long next, end;
+
+ pud = READ_ONCE(*pudp);
+
+ if (!pud_table(pud)) {
+ VM_WARN_ON(1);
+ return 1;
+ }
+
+ table = pmd_offset(pudp, addr);
+ pmdp = table;
+ next = addr;
+ end = addr + PUD_SIZE;
+ do {
+ pmd_free_pte_page(pmdp, next);
+ } while (pmdp++, next += PMD_SIZE, next != end);
+
+ pud_clear(pudp);
+ __flush_tlb_kernel_pgtable(addr);
+ pmd_free(NULL, table);
+ return 1;
+}
+
+#ifdef CONFIG_MEMORY_HOTPLUG
+static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size)
+{
+ unsigned long end = start + size;
+
+ WARN_ON(pgdir != init_mm.pgd);
+ WARN_ON((start < PAGE_OFFSET) || (end > PAGE_END));
+
+ unmap_hotplug_range(start, end, false, NULL);
+ free_empty_tables(start, end, PAGE_OFFSET, PAGE_END);
+}
+
+struct range arch_get_mappable_range(void)
+{
+ struct range mhp_range;
+ u64 start_linear_pa = __pa(_PAGE_OFFSET(vabits_actual));
+ u64 end_linear_pa = __pa(PAGE_END - 1);
+
+ if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
+ /*
+ * Check for a wrap, it is possible because of randomized linear
+ * mapping the start physical address is actually bigger than
+ * the end physical address. In this case set start to zero
+ * because [0, end_linear_pa] range must still be able to cover
+ * all addressable physical addresses.
+ */
+ if (start_linear_pa > end_linear_pa)
+ start_linear_pa = 0;
+ }
+
+ WARN_ON(start_linear_pa > end_linear_pa);
+
+ /*
+ * Linear mapping region is the range [PAGE_OFFSET..(PAGE_END - 1)]
+ * accommodating both its ends but excluding PAGE_END. Max physical
+ * range which can be mapped inside this linear mapping range, must
+ * also be derived from its end points.
+ */
+ mhp_range.start = start_linear_pa;
+ mhp_range.end = end_linear_pa;
+
+ return mhp_range;
+}
+
+int arch_add_memory(int nid, u64 start, u64 size,
+ struct mhp_params *params)
+{
+ int ret, flags = NO_EXEC_MAPPINGS;
+
+ VM_BUG_ON(!mhp_range_allowed(start, size, true));
+
+ if (can_set_direct_map())
+ flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
+
+ __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start),
+ size, params->pgprot, __pgd_pgtable_alloc,
+ flags);
+
+ memblock_clear_nomap(start, size);
+
+ ret = __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT,
+ params);
+ if (ret)
+ __remove_pgd_mapping(swapper_pg_dir,
+ __phys_to_virt(start), size);
+ else {
+ max_pfn = PFN_UP(start + size);
+ max_low_pfn = max_pfn;
+ }
+
+ return ret;
+}
+
+void arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap)
+{
+ unsigned long start_pfn = start >> PAGE_SHIFT;
+ unsigned long nr_pages = size >> PAGE_SHIFT;
+
+ __remove_pages(start_pfn, nr_pages, altmap);
+ __remove_pgd_mapping(swapper_pg_dir, __phys_to_virt(start), size);
+}
+
+/*
+ * This memory hotplug notifier helps prevent boot memory from being
+ * inadvertently removed as it blocks pfn range offlining process in
+ * __offline_pages(). Hence this prevents both offlining as well as
+ * removal process for boot memory which is initially always online.
+ * In future if and when boot memory could be removed, this notifier
+ * should be dropped and free_hotplug_page_range() should handle any
+ * reserved pages allocated during boot.
+ */
+static int prevent_bootmem_remove_notifier(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ struct mem_section *ms;
+ struct memory_notify *arg = data;
+ unsigned long end_pfn = arg->start_pfn + arg->nr_pages;
+ unsigned long pfn = arg->start_pfn;
+
+ if ((action != MEM_GOING_OFFLINE) && (action != MEM_OFFLINE))
+ return NOTIFY_OK;
+
+ for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
+ unsigned long start = PFN_PHYS(pfn);
+ unsigned long end = start + (1UL << PA_SECTION_SHIFT);
+
+ ms = __pfn_to_section(pfn);
+ if (!early_section(ms))
+ continue;
+
+ if (action == MEM_GOING_OFFLINE) {
+ /*
+ * Boot memory removal is not supported. Prevent
+ * it via blocking any attempted offline request
+ * for the boot memory and just report it.
+ */
+ pr_warn("Boot memory [%lx %lx] offlining attempted\n", start, end);
+ return NOTIFY_BAD;
+ } else if (action == MEM_OFFLINE) {
+ /*
+ * This should have never happened. Boot memory
+ * offlining should have been prevented by this
+ * very notifier. Probably some memory removal
+ * procedure might have changed which would then
+ * require further debug.
+ */
+ pr_err("Boot memory [%lx %lx] offlined\n", start, end);
+
+ /*
+ * Core memory hotplug does not process a return
+ * code from the notifier for MEM_OFFLINE events.
+ * The error condition has been reported. Return
+ * from here as if ignored.
+ */
+ return NOTIFY_DONE;
+ }
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block prevent_bootmem_remove_nb = {
+ .notifier_call = prevent_bootmem_remove_notifier,
+};
+
+/*
+ * This ensures that boot memory sections on the platform are online
+ * from early boot. Memory sections could not be prevented from being
+ * offlined, unless for some reason they are not online to begin with.
+ * This helps validate the basic assumption on which the above memory
+ * event notifier works to prevent boot memory section offlining and
+ * its possible removal.
+ */
+static void validate_bootmem_online(void)
+{
+ phys_addr_t start, end, addr;
+ struct mem_section *ms;
+ u64 i;
+
+ /*
+ * Scanning across all memblock might be expensive
+ * on some big memory systems. Hence enable this
+ * validation only with DEBUG_VM.
+ */
+ if (!IS_ENABLED(CONFIG_DEBUG_VM))
+ return;
+
+ for_each_mem_range(i, &start, &end) {
+ for (addr = start; addr < end; addr += (1UL << PA_SECTION_SHIFT)) {
+ ms = __pfn_to_section(PHYS_PFN(addr));
+
+ /*
+ * All memory ranges in the system at this point
+ * should have been marked as early sections.
+ */
+ WARN_ON(!early_section(ms));
+
+ /*
+ * Memory notifier mechanism here to prevent boot
+ * memory offlining depends on the fact that each
+ * early section memory on the system is initially
+ * online. Otherwise a given memory section which
+ * is already offline will be overlooked and can
+ * be removed completely. Call out such sections.
+ */
+ if (!online_section(ms))
+ pr_err("Boot memory [%llx %llx] is offline, can be removed\n",
+ addr, addr + (1UL << PA_SECTION_SHIFT));
+ }
+ }
+}
+
+static int __init prevent_bootmem_remove_init(void)
+{
+ int ret = 0;
+
+ if (!IS_ENABLED(CONFIG_MEMORY_HOTREMOVE))
+ return ret;
+
+ validate_bootmem_online();
+ ret = register_memory_notifier(&prevent_bootmem_remove_nb);
+ if (ret)
+ pr_err("%s: Notifier registration failed %d\n", __func__, ret);
+
+ return ret;
+}
+early_initcall(prevent_bootmem_remove_init);
+#endif
+
+pte_t ptep_modify_prot_start(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep)
+{
+ if (IS_ENABLED(CONFIG_ARM64_ERRATUM_2645198) &&
+ cpus_have_const_cap(ARM64_WORKAROUND_2645198)) {
+ /*
+ * Break-before-make (BBM) is required for all user space mappings
+ * when the permission changes from executable to non-executable
+ * in cases where cpu is affected with errata #2645198.
+ */
+ if (pte_user_exec(READ_ONCE(*ptep)))
+ return ptep_clear_flush(vma, addr, ptep);
+ }
+ return ptep_get_and_clear(vma->vm_mm, addr, ptep);
+}
+
+void ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep,
+ pte_t old_pte, pte_t pte)
+{
+ set_pte_at(vma->vm_mm, addr, ptep, pte);
+}