// SPDX-License-Identifier: GPL-2.0-only /* * Based on arch/arm/mm/init.c * * Copyright (C) 1995-2005 Russell King * Copyright (C) 2012 ARM Ltd. */ #include <linux/kernel.h> #include <linux/export.h> #include <linux/errno.h> #include <linux/swap.h> #include <linux/init.h> #include <linux/cache.h> #include <linux/mman.h> #include <linux/nodemask.h> #include <linux/initrd.h> #include <linux/gfp.h> #include <linux/memblock.h> #include <linux/sort.h> #include <linux/of.h> #include <linux/of_fdt.h> #include <linux/dma-direct.h> #include <linux/dma-map-ops.h> #include <linux/efi.h> #include <linux/swiotlb.h> #include <linux/vmalloc.h> #include <linux/mm.h> #include <linux/kexec.h> #include <linux/crash_dump.h> #include <linux/hugetlb.h> #include <linux/acpi_iort.h> #include <linux/kmemleak.h> #include <asm/boot.h> #include <asm/fixmap.h> #include <asm/kasan.h> #include <asm/kernel-pgtable.h> #include <asm/kvm_host.h> #include <asm/memory.h> #include <asm/numa.h> #include <asm/sections.h> #include <asm/setup.h> #include <linux/sizes.h> #include <asm/tlb.h> #include <asm/alternative.h> #include <asm/xen/swiotlb-xen.h> /* * We need to be able to catch inadvertent references to memstart_addr * that occur (potentially in generic code) before arm64_memblock_init() * executes, which assigns it its actual value. So use a default value * that cannot be mistaken for a real physical address. */ s64 memstart_addr __ro_after_init = -1; EXPORT_SYMBOL(memstart_addr); /* * If the corresponding config options are enabled, we create both ZONE_DMA * and ZONE_DMA32. By default ZONE_DMA covers the 32-bit addressable memory * unless restricted on specific platforms (e.g. 30-bit on Raspberry Pi 4). * In such case, ZONE_DMA32 covers the rest of the 32-bit addressable memory, * otherwise it is empty. * * Memory reservation for crash kernel either done early or deferred * depending on DMA memory zones configs (ZONE_DMA) -- * * In absence of ZONE_DMA configs arm64_dma_phys_limit initialized * here instead of max_zone_phys(). This lets early reservation of * crash kernel memory which has a dependency on arm64_dma_phys_limit. * Reserving memory early for crash kernel allows linear creation of block * mappings (greater than page-granularity) for all the memory bank rangs. * In this scheme a comparatively quicker boot is observed. * * If ZONE_DMA configs are defined, crash kernel memory reservation * is delayed until DMA zone memory range size initialization performed in * zone_sizes_init(). The defer is necessary to steer clear of DMA zone * memory range to avoid overlap allocation. So crash kernel memory boundaries * are not known when mapping all bank memory ranges, which otherwise means * not possible to exclude crash kernel range from creating block mappings * so page-granularity mappings are created for the entire memory range. * Hence a slightly slower boot is observed. * * Note: Page-granularity mappings are necessary for crash kernel memory * range for shrinking its size via /sys/kernel/kexec_crash_size interface. */ #if IS_ENABLED(CONFIG_ZONE_DMA) || IS_ENABLED(CONFIG_ZONE_DMA32) phys_addr_t __ro_after_init arm64_dma_phys_limit; #else phys_addr_t __ro_after_init arm64_dma_phys_limit = PHYS_MASK + 1; #endif /* Current arm64 boot protocol requires 2MB alignment */ #define CRASH_ALIGN SZ_2M #define CRASH_ADDR_LOW_MAX arm64_dma_phys_limit #define CRASH_ADDR_HIGH_MAX (PHYS_MASK + 1) static int __init reserve_crashkernel_low(unsigned long long low_size) { unsigned long long low_base; low_base = memblock_phys_alloc_range(low_size, CRASH_ALIGN, 0, CRASH_ADDR_LOW_MAX); if (!low_base) { pr_err("cannot allocate crashkernel low memory (size:0x%llx).\n", low_size); return -ENOMEM; } pr_info("crashkernel low memory reserved: 0x%08llx - 0x%08llx (%lld MB)\n", low_base, low_base + low_size, low_size >> 20); crashk_low_res.start = low_base; crashk_low_res.end = low_base + low_size - 1; insert_resource(&iomem_resource, &crashk_low_res); return 0; } /* * reserve_crashkernel() - reserves memory for crash kernel * * This function reserves memory area given in "crashkernel=" kernel command * line parameter. The memory reserved is used by dump capture kernel when * primary kernel is crashing. */ static void __init reserve_crashkernel(void) { unsigned long long crash_base, crash_size; unsigned long long crash_low_size = 0; unsigned long long crash_max = CRASH_ADDR_LOW_MAX; char *cmdline = boot_command_line; int ret; if (!IS_ENABLED(CONFIG_KEXEC_CORE)) return; /* crashkernel=X[@offset] */ ret = parse_crashkernel(cmdline, memblock_phys_mem_size(), &crash_size, &crash_base); if (ret == -ENOENT) { ret = parse_crashkernel_high(cmdline, 0, &crash_size, &crash_base); if (ret || !crash_size) return; /* * crashkernel=Y,low can be specified or not, but invalid value * is not allowed. */ ret = parse_crashkernel_low(cmdline, 0, &crash_low_size, &crash_base); if (ret && (ret != -ENOENT)) return; crash_max = CRASH_ADDR_HIGH_MAX; } else if (ret || !crash_size) { /* The specified value is invalid */ return; } crash_size = PAGE_ALIGN(crash_size); /* User specifies base address explicitly. */ if (crash_base) crash_max = crash_base + crash_size; crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base, crash_max); if (!crash_base) { pr_warn("cannot allocate crashkernel (size:0x%llx)\n", crash_size); return; } if ((crash_base >= CRASH_ADDR_LOW_MAX) && crash_low_size && reserve_crashkernel_low(crash_low_size)) { memblock_phys_free(crash_base, crash_size); return; } pr_info("crashkernel reserved: 0x%016llx - 0x%016llx (%lld MB)\n", crash_base, crash_base + crash_size, crash_size >> 20); /* * The crashkernel memory will be removed from the kernel linear * map. Inform kmemleak so that it won't try to access it. */ kmemleak_ignore_phys(crash_base); if (crashk_low_res.end) kmemleak_ignore_phys(crashk_low_res.start); crashk_res.start = crash_base; crashk_res.end = crash_base + crash_size - 1; insert_resource(&iomem_resource, &crashk_res); } /* * Return the maximum physical address for a zone accessible by the given bits * limit. If DRAM starts above 32-bit, expand the zone to the maximum * available memory, otherwise cap it at 32-bit. */ static phys_addr_t __init max_zone_phys(unsigned int zone_bits) { phys_addr_t zone_mask = DMA_BIT_MASK(zone_bits); phys_addr_t phys_start = memblock_start_of_DRAM(); if (phys_start > U32_MAX) zone_mask = PHYS_ADDR_MAX; else if (phys_start > zone_mask) zone_mask = U32_MAX; return min(zone_mask, memblock_end_of_DRAM() - 1) + 1; } static void __init zone_sizes_init(void) { unsigned long max_zone_pfns[MAX_NR_ZONES] = {0}; unsigned int __maybe_unused acpi_zone_dma_bits; unsigned int __maybe_unused dt_zone_dma_bits; phys_addr_t __maybe_unused dma32_phys_limit = max_zone_phys(32); #ifdef CONFIG_ZONE_DMA acpi_zone_dma_bits = fls64(acpi_iort_dma_get_max_cpu_address()); dt_zone_dma_bits = fls64(of_dma_get_max_cpu_address(NULL)); zone_dma_bits = min3(32U, dt_zone_dma_bits, acpi_zone_dma_bits); arm64_dma_phys_limit = max_zone_phys(zone_dma_bits); max_zone_pfns[ZONE_DMA] = PFN_DOWN(arm64_dma_phys_limit); #endif #ifdef CONFIG_ZONE_DMA32 max_zone_pfns[ZONE_DMA32] = PFN_DOWN(dma32_phys_limit); if (!arm64_dma_phys_limit) arm64_dma_phys_limit = dma32_phys_limit; #endif max_zone_pfns[ZONE_NORMAL] = max_pfn; free_area_init(max_zone_pfns); } int pfn_is_map_memory(unsigned long pfn) { phys_addr_t addr = PFN_PHYS(pfn); /* avoid false positives for bogus PFNs, see comment in pfn_valid() */ if (PHYS_PFN(addr) != pfn) return 0; return memblock_is_map_memory(addr); } EXPORT_SYMBOL(pfn_is_map_memory); static phys_addr_t memory_limit __ro_after_init = PHYS_ADDR_MAX; /* * Limit the memory size that was specified via FDT. */ static int __init early_mem(char *p) { if (!p) return 1; memory_limit = memparse(p, &p) & PAGE_MASK; pr_notice("Memory limited to %lldMB\n", memory_limit >> 20); return 0; } early_param("mem", early_mem); void __init arm64_memblock_init(void) { s64 linear_region_size = PAGE_END - _PAGE_OFFSET(vabits_actual); /* * Corner case: 52-bit VA capable systems running KVM in nVHE mode may * be limited in their ability to support a linear map that exceeds 51 * bits of VA space, depending on the placement of the ID map. Given * that the placement of the ID map may be randomized, let's simply * limit the kernel's linear map to 51 bits as well if we detect this * configuration. */ if (IS_ENABLED(CONFIG_KVM) && vabits_actual == 52 && is_hyp_mode_available() && !is_kernel_in_hyp_mode()) { pr_info("Capping linear region to 51 bits for KVM in nVHE mode on LVA capable hardware.\n"); linear_region_size = min_t(u64, linear_region_size, BIT(51)); } /* Remove memory above our supported physical address size */ memblock_remove(1ULL << PHYS_MASK_SHIFT, ULLONG_MAX); /* * Select a suitable value for the base of physical memory. */ memstart_addr = round_down(memblock_start_of_DRAM(), ARM64_MEMSTART_ALIGN); if ((memblock_end_of_DRAM() - memstart_addr) > linear_region_size) pr_warn("Memory doesn't fit in the linear mapping, VA_BITS too small\n"); /* * Remove the memory that we will not be able to cover with the * linear mapping. Take care not to clip the kernel which may be * high in memory. */ memblock_remove(max_t(u64, memstart_addr + linear_region_size, __pa_symbol(_end)), ULLONG_MAX); if (memstart_addr + linear_region_size < memblock_end_of_DRAM()) { /* ensure that memstart_addr remains sufficiently aligned */ memstart_addr = round_up(memblock_end_of_DRAM() - linear_region_size, ARM64_MEMSTART_ALIGN); memblock_remove(0, memstart_addr); } /* * If we are running with a 52-bit kernel VA config on a system that * does not support it, we have to place the available physical * memory in the 48-bit addressable part of the linear region, i.e., * we have to move it upward. Since memstart_addr represents the * physical address of PAGE_OFFSET, we have to *subtract* from it. */ if (IS_ENABLED(CONFIG_ARM64_VA_BITS_52) && (vabits_actual != 52)) memstart_addr -= _PAGE_OFFSET(48) - _PAGE_OFFSET(52); /* * Apply the memory limit if it was set. Since the kernel may be loaded * high up in memory, add back the kernel region that must be accessible * via the linear mapping. */ if (memory_limit != PHYS_ADDR_MAX) { memblock_mem_limit_remove_map(memory_limit); memblock_add(__pa_symbol(_text), (u64)(_end - _text)); } if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && phys_initrd_size) { /* * Add back the memory we just removed if it results in the * initrd to become inaccessible via the linear mapping. * Otherwise, this is a no-op */ u64 base = phys_initrd_start & PAGE_MASK; u64 size = PAGE_ALIGN(phys_initrd_start + phys_initrd_size) - base; /* * We can only add back the initrd memory if we don't end up * with more memory than we can address via the linear mapping. * It is up to the bootloader to position the kernel and the * initrd reasonably close to each other (i.e., within 32 GB of * each other) so that all granule/#levels combinations can * always access both. */ if (WARN(base < memblock_start_of_DRAM() || base + size > memblock_start_of_DRAM() + linear_region_size, "initrd not fully accessible via the linear mapping -- please check your bootloader ...\n")) { phys_initrd_size = 0; } else { memblock_add(base, size); memblock_clear_nomap(base, size); memblock_reserve(base, size); } } if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { extern u16 memstart_offset_seed; u64 mmfr0 = read_cpuid(ID_AA64MMFR0_EL1); int parange = cpuid_feature_extract_unsigned_field( mmfr0, ID_AA64MMFR0_PARANGE_SHIFT); s64 range = linear_region_size - BIT(id_aa64mmfr0_parange_to_phys_shift(parange)); /* * If the size of the linear region exceeds, by a sufficient * margin, the size of the region that the physical memory can * span, randomize the linear region as well. */ if (memstart_offset_seed > 0 && range >= (s64)ARM64_MEMSTART_ALIGN) { range /= ARM64_MEMSTART_ALIGN; memstart_addr -= ARM64_MEMSTART_ALIGN * ((range * memstart_offset_seed) >> 16); } } /* * Register the kernel text, kernel data, initrd, and initial * pagetables with memblock. */ memblock_reserve(__pa_symbol(_stext), _end - _stext); if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && phys_initrd_size) { /* the generic initrd code expects virtual addresses */ initrd_start = __phys_to_virt(phys_initrd_start); initrd_end = initrd_start + phys_initrd_size; } early_init_fdt_scan_reserved_mem(); if (!defer_reserve_crashkernel()) reserve_crashkernel(); high_memory = __va(memblock_end_of_DRAM() - 1) + 1; } void __init bootmem_init(void) { unsigned long min, max; min = PFN_UP(memblock_start_of_DRAM()); max = PFN_DOWN(memblock_end_of_DRAM()); early_memtest(min << PAGE_SHIFT, max << PAGE_SHIFT); max_pfn = max_low_pfn = max; min_low_pfn = min; arch_numa_init(); /* * must be done after arch_numa_init() which calls numa_init() to * initialize node_online_map that gets used in hugetlb_cma_reserve() * while allocating required CMA size across online nodes. */ #if defined(CONFIG_HUGETLB_PAGE) && defined(CONFIG_CMA) arm64_hugetlb_cma_reserve(); #endif dma_pernuma_cma_reserve(); kvm_hyp_reserve(); /* * sparse_init() tries to allocate memory from memblock, so must be * done after the fixed reservations */ sparse_init(); zone_sizes_init(); /* * Reserve the CMA area after arm64_dma_phys_limit was initialised. */ dma_contiguous_reserve(arm64_dma_phys_limit); /* * request_standard_resources() depends on crashkernel's memory being * reserved, so do it here. */ if (defer_reserve_crashkernel()) reserve_crashkernel(); memblock_dump_all(); } /* * mem_init() marks the free areas in the mem_map and tells us how much memory * is free. This is done after various parts of the system have claimed their * memory after the kernel image. */ void __init mem_init(void) { swiotlb_init(max_pfn > PFN_DOWN(arm64_dma_phys_limit), SWIOTLB_VERBOSE); /* this will put all unused low memory onto the freelists */ memblock_free_all(); /* * Check boundaries twice: Some fundamental inconsistencies can be * detected at build time already. */ #ifdef CONFIG_COMPAT BUILD_BUG_ON(TASK_SIZE_32 > DEFAULT_MAP_WINDOW_64); #endif /* * Selected page table levels should match when derived from * scratch using the virtual address range and page size. */ BUILD_BUG_ON(ARM64_HW_PGTABLE_LEVELS(CONFIG_ARM64_VA_BITS) != CONFIG_PGTABLE_LEVELS); if (PAGE_SIZE >= 16384 && get_num_physpages() <= 128) { extern int sysctl_overcommit_memory; /* * On a machine this small we won't get anywhere without * overcommit, so turn it on by default. */ sysctl_overcommit_memory = OVERCOMMIT_ALWAYS; } } void free_initmem(void) { free_reserved_area(lm_alias(__init_begin), lm_alias(__init_end), POISON_FREE_INITMEM, "unused kernel"); /* * Unmap the __init region but leave the VM area in place. This * prevents the region from being reused for kernel modules, which * is not supported by kallsyms. */ vunmap_range((u64)__init_begin, (u64)__init_end); } void dump_mem_limit(void) { if (memory_limit != PHYS_ADDR_MAX) { pr_emerg("Memory Limit: %llu MB\n", memory_limit >> 20); } else { pr_emerg("Memory Limit: none\n"); } }