diff options
Diffstat (limited to 'arch/arm64/mm/mmu.c')
| -rw-r--r-- | arch/arm64/mm/mmu.c | 1595 |
1 files changed, 1595 insertions, 0 deletions
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c new file mode 100644 index 000000000..78f9fb638 --- /dev/null +++ b/arch/arm64/mm/mmu.c @@ -0,0 +1,1595 @@ +// 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/memory.h> +#include <linux/fs.h> +#include <linux/io.h> +#include <linux/mm.h> +#include <linux/vmalloc.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> + +#define NO_BLOCK_MAPPINGS BIT(0) +#define NO_CONT_MAPPINGS BIT(1) + +u64 idmap_t0sz = TCR_T0SZ(VA_BITS_MIN); +u64 idmap_ptrs_per_pgd = PTRS_PER_PGD; + +u64 __section(".mmuoff.data.write") vabits_actual; +EXPORT_SYMBOL(vabits_actual); + +u64 kimage_voffset __ro_after_init; +EXPORT_SYMBOL(kimage_voffset); + +/* + * 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 pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss; +static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused; +static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused; + +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_valid(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(PAGE_SIZE, PAGE_SIZE); + 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; +} + +static 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 (old == 0 || new == 0) + return true; + + /* 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)) { + phys_addr_t pte_phys; + BUG_ON(!pgtable_alloc); + pte_phys = pgtable_alloc(PAGE_SHIFT); + __pmd_populate(pmdp, pte_phys, PMD_TYPE_TABLE); + 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) & ~SECTION_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)) { + phys_addr_t pmd_phys; + BUG_ON(!pgtable_alloc); + pmd_phys = pgtable_alloc(PMD_SHIFT); + __pud_populate(pudp, pmd_phys, PUD_TYPE_TABLE); + 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 inline bool use_1G_block(unsigned long addr, unsigned long next, + unsigned long phys) +{ + if (PAGE_SHIFT != 12) + return false; + + if (((addr | next | phys) & ~PUD_MASK) != 0) + return false; + + return true; +} + +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)) { + phys_addr_t pud_phys; + BUG_ON(!pgtable_alloc); + pud_phys = pgtable_alloc(PUD_SHIFT); + __p4d_populate(p4dp, pud_phys, PUD_TYPE_TABLE); + p4d = READ_ONCE(*p4dp); + } + BUG_ON(p4d_bad(p4d)); + + /* + * No need for locking during early boot. And it doesn't work as + * expected with KASLR enabled. + */ + if (system_state != SYSTEM_BOOTING) + mutex_lock(&fixmap_lock); + 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 (use_1G_block(addr, next, phys) && + (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(); + if (system_state != SYSTEM_BOOTING) + mutex_unlock(&fixmap_lock); +} + +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) +{ + 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 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); + + /* + * 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 pgtable_pmd_page_ctor() becomes nop. + */ + if (shift == PAGE_SHIFT) + BUG_ON(!pgtable_pte_page_ctor(phys_to_page(pa))); + else if (shift == PMD_SHIFT) + BUG_ON(!pgtable_pmd_page_ctor(phys_to_page(pa))); + + 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. + */ +static 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(_text), (unsigned long)lm_alias(_text), + (unsigned long)__init_begin - (unsigned long)_text, + PAGE_KERNEL_RO); +} + +static bool crash_mem_map __initdata; + +static int __init enable_crash_mem_map(char *arg) +{ + /* + * Proper parameter parsing is done by reserve_crashkernel(). We only + * need to know if the linear map has to avoid block mappings so that + * the crashkernel reservations can be unmapped later. + */ + crash_mem_map = true; + + return 0; +} +early_param("crashkernel", enable_crash_mem_map); + +static void __init map_mem(pgd_t *pgdp) +{ + phys_addr_t kernel_start = __pa_symbol(_text); + phys_addr_t kernel_end = __pa_symbol(__init_begin); + phys_addr_t start, end; + int flags = 0; + u64 i; + + if (rodata_full || debug_pagealloc_enabled()) + 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); + +#ifdef CONFIG_KEXEC_CORE + if (crash_mem_map) { + if (IS_ENABLED(CONFIG_ZONE_DMA) || + IS_ENABLED(CONFIG_ZONE_DMA32)) + flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; + else if (crashk_res.end) + memblock_mark_nomap(crashk_res.start, + resource_size(&crashk_res)); + } +#endif + + /* 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 [_text, __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); + + /* + * Use page-level mappings here so that we can shrink the region + * in page granularity and put back unused memory to buddy system + * through /sys/kernel/kexec_crash_size interface. + */ +#ifdef CONFIG_KEXEC_CORE + if (crash_mem_map && + !IS_ENABLED(CONFIG_ZONE_DMA) && !IS_ENABLED(CONFIG_ZONE_DMA32)) { + if (crashk_res.end) { + __map_memblock(pgdp, crashk_res.start, + crashk_res.end + 1, + PAGE_KERNEL, + NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS); + memblock_clear_nomap(crashk_res.start, + resource_size(&crashk_res)); + } + } +#endif +} + +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 int __init parse_rodata(char *arg) +{ + int ret = strtobool(arg, &rodata_enabled); + if (!ret) { + rodata_full = false; + return 0; + } + + /* permit 'full' in addition to boolean options */ + if (strcmp(arg, "full")) + return -EINVAL; + + rodata_enabled = true; + rodata_full = true; + return 0; +} +early_param("rodata", parse_rodata); + +#ifdef CONFIG_UNMAP_KERNEL_AT_EL0 +static int __init map_entry_trampoline(void) +{ + int i; + + pgprot_t prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; + 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_RANDOMIZE_BASE)) { + extern char __entry_tramp_data_start[]; + + __set_fixmap(FIX_ENTRY_TRAMP_DATA, + __pa_symbol(__entry_tramp_data_start), + 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_s(SYS_ID_AA64PFR1_EL1); + return cpuid_feature_extract_unsigned_field(pfr1, + ID_AA64PFR1_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 = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; + + /* + * 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, _text, _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); + + if (!READ_ONCE(pgd_val(*pgd_offset_pgd(pgdp, FIXADDR_START)))) { + /* + * The fixmap falls in a separate pgd to the kernel, and doesn't + * live in the carveout for the swapper_pg_dir. We can simply + * re-use the existing dir for the fixmap. + */ + set_pgd(pgd_offset_pgd(pgdp, FIXADDR_START), + READ_ONCE(*pgd_offset_k(FIXADDR_START))); + } else if (CONFIG_PGTABLE_LEVELS > 3) { + pgd_t *bm_pgdp; + p4d_t *bm_p4dp; + pud_t *bm_pudp; + /* + * The fixmap shares its top level pgd entry with the kernel + * mapping. This can really only occur when we are running + * with 16k/4 levels, so we can simply reuse the pud level + * entry instead. + */ + BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); + bm_pgdp = pgd_offset_pgd(pgdp, FIXADDR_START); + bm_p4dp = p4d_offset(bm_pgdp, FIXADDR_START); + bm_pudp = pud_set_fixmap_offset(bm_p4dp, FIXADDR_START); + pud_populate(&init_mm, bm_pudp, lm_alias(bm_pmd)); + pud_clear_fixmap(); + } else { + BUG(); + } + + kasan_copy_shadow(pgdp); +} + +void __init paging_init(void) +{ + pgd_t *pgdp = pgd_set_fixmap(__pa_symbol(swapper_pg_dir)); + + map_kernel(pgdp); + map_mem(pgdp); + + pgd_clear_fixmap(); + + cpu_replace_ttbr1(lm_alias(swapper_pg_dir)); + init_mm.pgd = swapper_pg_dir; + + memblock_free(__pa_symbol(init_pg_dir), + __pa_symbol(init_pg_end) - __pa_symbol(init_pg_dir)); + + memblock_allow_resize(); +} + +/* + * Check whether a kernel address is valid (derived from arch/x86/). + */ +int kern_addr_valid(unsigned long addr) +{ + pgd_t *pgdp; + p4d_t *p4dp; + pud_t *pudp, pud; + pmd_t *pmdp, pmd; + pte_t *ptep, pte; + + addr = arch_kasan_reset_tag(addr); + if ((((long)addr) >> VA_BITS) != -1UL) + return 0; + + pgdp = pgd_offset_k(addr); + if (pgd_none(READ_ONCE(*pgdp))) + return 0; + + p4dp = p4d_offset(pgdp, addr); + if (p4d_none(READ_ONCE(*p4dp))) + return 0; + + pudp = pud_offset(p4dp, addr); + pud = READ_ONCE(*pudp); + if (pud_none(pud)) + return 0; + + if (pud_sect(pud)) + return pfn_valid(pud_pfn(pud)); + + pmdp = pmd_offset(pudp, addr); + pmd = READ_ONCE(*pmdp); + if (pmd_none(pmd)) + return 0; + + if (pmd_sect(pmd)) + return pfn_valid(pmd_pfn(pmd)); + + ptep = pte_offset_kernel(pmdp, addr); + pte = READ_ONCE(*ptep); + if (pte_none(pte)) + return 0; + + return pfn_valid(pte_pfn(pte)); +} + +#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 + +#ifdef CONFIG_SPARSEMEM_VMEMMAP +#if !ARM64_SWAPPER_USES_SECTION_MAPS +int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, + struct vmem_altmap *altmap) +{ + return vmemmap_populate_basepages(start, end, node, altmap); +} +#else /* !ARM64_SWAPPER_USES_SECTION_MAPS */ +int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, + struct vmem_altmap *altmap) +{ + unsigned long addr = start; + unsigned long next; + pgd_t *pgdp; + p4d_t *p4dp; + pud_t *pudp; + pmd_t *pmdp; + + do { + next = pmd_addr_end(addr, end); + + pgdp = vmemmap_pgd_populate(addr, node); + if (!pgdp) + return -ENOMEM; + + p4dp = vmemmap_p4d_populate(pgdp, addr, node); + if (!p4dp) + return -ENOMEM; + + pudp = vmemmap_pud_populate(p4dp, addr, node); + if (!pudp) + return -ENOMEM; + + pmdp = pmd_offset(pudp, addr); + if (pmd_none(READ_ONCE(*pmdp))) { + void *p = NULL; + + p = vmemmap_alloc_block_buf(PMD_SIZE, node, altmap); + if (!p) + return -ENOMEM; + + pmd_set_huge(pmdp, __pa(p), __pgprot(PROT_SECT_NORMAL)); + } else + vmemmap_verify((pte_t *)pmdp, node, addr, next); + } while (addr = next, addr != end); + + return 0; +} +#endif /* !ARM64_SWAPPER_USES_SECTION_MAPS */ +void vmemmap_free(unsigned long start, unsigned long end, + struct vmem_altmap *altmap) +{ +#ifdef CONFIG_MEMORY_HOTPLUG + 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 +} +#endif /* CONFIG_SPARSEMEM_VMEMMAP */ + +static inline pud_t * fixmap_pud(unsigned long addr) +{ + pgd_t *pgdp = pgd_offset_k(addr); + p4d_t *p4dp = p4d_offset(pgdp, addr); + p4d_t p4d = READ_ONCE(*p4dp); + + BUG_ON(p4d_none(p4d) || p4d_bad(p4d)); + + return pud_offset_kimg(p4dp, addr); +} + +static inline pmd_t * fixmap_pmd(unsigned long addr) +{ + pud_t *pudp = fixmap_pud(addr); + pud_t pud = READ_ONCE(*pudp); + + BUG_ON(pud_none(pud) || pud_bad(pud)); + + return pmd_offset_kimg(pudp, addr); +} + +static inline pte_t * fixmap_pte(unsigned long addr) +{ + return &bm_pte[pte_index(addr)]; +} + +/* + * The p*d_populate functions call virt_to_phys implicitly so they can't be used + * directly on kernel symbols (bm_p*d). This function is called too early to use + * lm_alias so __p*d_populate functions must be used to populate with the + * physical address from __pa_symbol. + */ +void __init early_fixmap_init(void) +{ + pgd_t *pgdp; + p4d_t *p4dp, p4d; + pud_t *pudp; + pmd_t *pmdp; + unsigned long addr = FIXADDR_START; + + pgdp = pgd_offset_k(addr); + p4dp = p4d_offset(pgdp, addr); + p4d = READ_ONCE(*p4dp); + if (CONFIG_PGTABLE_LEVELS > 3 && + !(p4d_none(p4d) || p4d_page_paddr(p4d) == __pa_symbol(bm_pud))) { + /* + * We only end up here if the kernel mapping and the fixmap + * share the top level pgd entry, which should only happen on + * 16k/4 levels configurations. + */ + BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); + pudp = pud_offset_kimg(p4dp, addr); + } else { + if (p4d_none(p4d)) + __p4d_populate(p4dp, __pa_symbol(bm_pud), PUD_TYPE_TABLE); + pudp = fixmap_pud(addr); + } + if (pud_none(READ_ONCE(*pudp))) + __pud_populate(pudp, __pa_symbol(bm_pmd), PMD_TYPE_TABLE); + pmdp = fixmap_pmd(addr); + __pmd_populate(pmdp, __pa_symbol(bm_pte), PMD_TYPE_TABLE); + + /* + * The boot-ioremap range spans multiple pmds, for which + * we are not prepared: + */ + BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT) + != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT)); + + if ((pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN))) + || pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) { + WARN_ON(1); + pr_warn("pmdp %p != %p, %p\n", + pmdp, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)), + fixmap_pmd(fix_to_virt(FIX_BTMAP_END))); + pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n", + fix_to_virt(FIX_BTMAP_BEGIN)); + pr_warn("fix_to_virt(FIX_BTMAP_END): %08lx\n", + fix_to_virt(FIX_BTMAP_END)); + + pr_warn("FIX_BTMAP_END: %d\n", FIX_BTMAP_END); + pr_warn("FIX_BTMAP_BEGIN: %d\n", FIX_BTMAP_BEGIN); + } +} + +/* + * Unusually, this is also called in IRQ context (ghes_iounmap_irq) so if we + * ever need to use IPIs for TLB broadcasting, then we're in trouble here. + */ +void __set_fixmap(enum fixed_addresses idx, + phys_addr_t phys, pgprot_t flags) +{ + unsigned long addr = __fix_to_virt(idx); + pte_t *ptep; + + BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses); + + ptep = fixmap_pte(addr); + + if (pgprot_val(flags)) { + set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, flags)); + } else { + pte_clear(&init_mm, addr, ptep); + flush_tlb_kernel_range(addr, addr+PAGE_SIZE); + } +} + +void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot) +{ + const u64 dt_virt_base = __fix_to_virt(FIX_FDT); + int offset; + void *dt_virt; + + /* + * Check whether the physical FDT address is set and meets the minimum + * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be + * at least 8 bytes so that we can always access the magic and size + * fields of the FDT header after mapping the first chunk, double check + * here if that is indeed the case. + */ + BUILD_BUG_ON(MIN_FDT_ALIGN < 8); + if (!dt_phys || dt_phys % MIN_FDT_ALIGN) + return NULL; + + /* + * Make sure that the FDT region can be mapped without the need to + * allocate additional translation table pages, so that it is safe + * to call create_mapping_noalloc() this early. + * + * On 64k pages, the FDT will be mapped using PTEs, so we need to + * be in the same PMD as the rest of the fixmap. + * On 4k pages, we'll use section mappings for the FDT so we only + * have to be in the same PUD. + */ + BUILD_BUG_ON(dt_virt_base % SZ_2M); + + BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT != + __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT); + + offset = dt_phys % SWAPPER_BLOCK_SIZE; + dt_virt = (void *)dt_virt_base + offset; + + /* map the first chunk so we can read the size from the header */ + create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), + dt_virt_base, SWAPPER_BLOCK_SIZE, prot); + + if (fdt_magic(dt_virt) != FDT_MAGIC) + return NULL; + + *size = fdt_totalsize(dt_virt); + if (*size > MAX_FDT_SIZE) + return NULL; + + if (offset + *size > SWAPPER_BLOCK_SIZE) + create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base, + round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot); + + return dt_virt; +} + +int __init arch_ioremap_p4d_supported(void) +{ + return 0; +} + +int __init arch_ioremap_pud_supported(void) +{ + /* + * Only 4k granule supports level 1 block mappings. + * SW table walks can't handle removal of intermediate entries. + */ + return IS_ENABLED(CONFIG_ARM64_4K_PAGES) && + !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS); +} + +int __init arch_ioremap_pmd_supported(void) +{ + /* See arch_ioremap_pud_supported() */ + return !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS); +} + +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; +} + +int p4d_free_pud_page(p4d_t *p4d, unsigned long addr) +{ + return 0; /* Don't attempt a block mapping */ +} + +#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); +} + +static bool inside_linear_region(u64 start, u64 size) +{ + 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. + */ + return start >= start_linear_pa && (start + size - 1) <= end_linear_pa; +} + +int arch_add_memory(int nid, u64 start, u64 size, + struct mhp_params *params) +{ + int ret, flags = 0; + + if (!inside_linear_region(start, size)) { + pr_err("[%llx %llx] is outside linear mapping region\n", start, start + size); + return -EINVAL; + } + + if (rodata_full || debug_pagealloc_enabled()) + 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(int nid, 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) + return NOTIFY_OK; + + for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) { + ms = __pfn_to_section(pfn); + if (early_section(ms)) + return NOTIFY_BAD; + } + return NOTIFY_OK; +} + +static struct notifier_block prevent_bootmem_remove_nb = { + .notifier_call = prevent_bootmem_remove_notifier, +}; + +static int __init prevent_bootmem_remove_init(void) +{ + return register_memory_notifier(&prevent_bootmem_remove_nb); +} +device_initcall(prevent_bootmem_remove_init); +#endif |