v4.19.13 snapshot.
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
new file mode 100644
index 0000000..faca978
--- /dev/null
+++ b/arch/x86/mm/init.c
@@ -0,0 +1,949 @@
+#include <linux/gfp.h>
+#include <linux/initrd.h>
+#include <linux/ioport.h>
+#include <linux/swap.h>
+#include <linux/memblock.h>
+#include <linux/bootmem.h> /* for max_low_pfn */
+#include <linux/swapfile.h>
+#include <linux/swapops.h>
+
+#include <asm/set_memory.h>
+#include <asm/e820/api.h>
+#include <asm/init.h>
+#include <asm/page.h>
+#include <asm/page_types.h>
+#include <asm/sections.h>
+#include <asm/setup.h>
+#include <asm/tlbflush.h>
+#include <asm/tlb.h>
+#include <asm/proto.h>
+#include <asm/dma.h> /* for MAX_DMA_PFN */
+#include <asm/microcode.h>
+#include <asm/kaslr.h>
+#include <asm/hypervisor.h>
+#include <asm/cpufeature.h>
+#include <asm/pti.h>
+
+/*
+ * We need to define the tracepoints somewhere, and tlb.c
+ * is only compied when SMP=y.
+ */
+#define CREATE_TRACE_POINTS
+#include <trace/events/tlb.h>
+
+#include "mm_internal.h"
+
+/*
+ * Tables translating between page_cache_type_t and pte encoding.
+ *
+ * The default values are defined statically as minimal supported mode;
+ * WC and WT fall back to UC-. pat_init() updates these values to support
+ * more cache modes, WC and WT, when it is safe to do so. See pat_init()
+ * for the details. Note, __early_ioremap() used during early boot-time
+ * takes pgprot_t (pte encoding) and does not use these tables.
+ *
+ * Index into __cachemode2pte_tbl[] is the cachemode.
+ *
+ * Index into __pte2cachemode_tbl[] are the caching attribute bits of the pte
+ * (_PAGE_PWT, _PAGE_PCD, _PAGE_PAT) at index bit positions 0, 1, 2.
+ */
+uint16_t __cachemode2pte_tbl[_PAGE_CACHE_MODE_NUM] = {
+ [_PAGE_CACHE_MODE_WB ] = 0 | 0 ,
+ [_PAGE_CACHE_MODE_WC ] = 0 | _PAGE_PCD,
+ [_PAGE_CACHE_MODE_UC_MINUS] = 0 | _PAGE_PCD,
+ [_PAGE_CACHE_MODE_UC ] = _PAGE_PWT | _PAGE_PCD,
+ [_PAGE_CACHE_MODE_WT ] = 0 | _PAGE_PCD,
+ [_PAGE_CACHE_MODE_WP ] = 0 | _PAGE_PCD,
+};
+EXPORT_SYMBOL(__cachemode2pte_tbl);
+
+uint8_t __pte2cachemode_tbl[8] = {
+ [__pte2cm_idx( 0 | 0 | 0 )] = _PAGE_CACHE_MODE_WB,
+ [__pte2cm_idx(_PAGE_PWT | 0 | 0 )] = _PAGE_CACHE_MODE_UC_MINUS,
+ [__pte2cm_idx( 0 | _PAGE_PCD | 0 )] = _PAGE_CACHE_MODE_UC_MINUS,
+ [__pte2cm_idx(_PAGE_PWT | _PAGE_PCD | 0 )] = _PAGE_CACHE_MODE_UC,
+ [__pte2cm_idx( 0 | 0 | _PAGE_PAT)] = _PAGE_CACHE_MODE_WB,
+ [__pte2cm_idx(_PAGE_PWT | 0 | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC_MINUS,
+ [__pte2cm_idx(0 | _PAGE_PCD | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC_MINUS,
+ [__pte2cm_idx(_PAGE_PWT | _PAGE_PCD | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC,
+};
+EXPORT_SYMBOL(__pte2cachemode_tbl);
+
+static unsigned long __initdata pgt_buf_start;
+static unsigned long __initdata pgt_buf_end;
+static unsigned long __initdata pgt_buf_top;
+
+static unsigned long min_pfn_mapped;
+
+static bool __initdata can_use_brk_pgt = true;
+
+/*
+ * Pages returned are already directly mapped.
+ *
+ * Changing that is likely to break Xen, see commit:
+ *
+ * 279b706 x86,xen: introduce x86_init.mapping.pagetable_reserve
+ *
+ * for detailed information.
+ */
+__ref void *alloc_low_pages(unsigned int num)
+{
+ unsigned long pfn;
+ int i;
+
+ if (after_bootmem) {
+ unsigned int order;
+
+ order = get_order((unsigned long)num << PAGE_SHIFT);
+ return (void *)__get_free_pages(GFP_ATOMIC | __GFP_ZERO, order);
+ }
+
+ if ((pgt_buf_end + num) > pgt_buf_top || !can_use_brk_pgt) {
+ unsigned long ret = 0;
+
+ if (min_pfn_mapped < max_pfn_mapped) {
+ ret = memblock_find_in_range(
+ min_pfn_mapped << PAGE_SHIFT,
+ max_pfn_mapped << PAGE_SHIFT,
+ PAGE_SIZE * num , PAGE_SIZE);
+ }
+ if (ret)
+ memblock_reserve(ret, PAGE_SIZE * num);
+ else if (can_use_brk_pgt)
+ ret = __pa(extend_brk(PAGE_SIZE * num, PAGE_SIZE));
+
+ if (!ret)
+ panic("alloc_low_pages: can not alloc memory");
+
+ pfn = ret >> PAGE_SHIFT;
+ } else {
+ pfn = pgt_buf_end;
+ pgt_buf_end += num;
+ printk(KERN_DEBUG "BRK [%#010lx, %#010lx] PGTABLE\n",
+ pfn << PAGE_SHIFT, (pgt_buf_end << PAGE_SHIFT) - 1);
+ }
+
+ for (i = 0; i < num; i++) {
+ void *adr;
+
+ adr = __va((pfn + i) << PAGE_SHIFT);
+ clear_page(adr);
+ }
+
+ return __va(pfn << PAGE_SHIFT);
+}
+
+/*
+ * By default need 3 4k for initial PMD_SIZE, 3 4k for 0-ISA_END_ADDRESS.
+ * With KASLR memory randomization, depending on the machine e820 memory
+ * and the PUD alignment. We may need twice more pages when KASLR memory
+ * randomization is enabled.
+ */
+#ifndef CONFIG_RANDOMIZE_MEMORY
+#define INIT_PGD_PAGE_COUNT 6
+#else
+#define INIT_PGD_PAGE_COUNT 12
+#endif
+#define INIT_PGT_BUF_SIZE (INIT_PGD_PAGE_COUNT * PAGE_SIZE)
+RESERVE_BRK(early_pgt_alloc, INIT_PGT_BUF_SIZE);
+void __init early_alloc_pgt_buf(void)
+{
+ unsigned long tables = INIT_PGT_BUF_SIZE;
+ phys_addr_t base;
+
+ base = __pa(extend_brk(tables, PAGE_SIZE));
+
+ pgt_buf_start = base >> PAGE_SHIFT;
+ pgt_buf_end = pgt_buf_start;
+ pgt_buf_top = pgt_buf_start + (tables >> PAGE_SHIFT);
+}
+
+int after_bootmem;
+
+early_param_on_off("gbpages", "nogbpages", direct_gbpages, CONFIG_X86_DIRECT_GBPAGES);
+
+struct map_range {
+ unsigned long start;
+ unsigned long end;
+ unsigned page_size_mask;
+};
+
+static int page_size_mask;
+
+static void __init probe_page_size_mask(void)
+{
+ /*
+ * For pagealloc debugging, identity mapping will use small pages.
+ * This will simplify cpa(), which otherwise needs to support splitting
+ * large pages into small in interrupt context, etc.
+ */
+ if (boot_cpu_has(X86_FEATURE_PSE) && !debug_pagealloc_enabled())
+ page_size_mask |= 1 << PG_LEVEL_2M;
+ else
+ direct_gbpages = 0;
+
+ /* Enable PSE if available */
+ if (boot_cpu_has(X86_FEATURE_PSE))
+ cr4_set_bits_and_update_boot(X86_CR4_PSE);
+
+ /* Enable PGE if available */
+ __supported_pte_mask &= ~_PAGE_GLOBAL;
+ if (boot_cpu_has(X86_FEATURE_PGE)) {
+ cr4_set_bits_and_update_boot(X86_CR4_PGE);
+ __supported_pte_mask |= _PAGE_GLOBAL;
+ }
+
+ /* By the default is everything supported: */
+ __default_kernel_pte_mask = __supported_pte_mask;
+ /* Except when with PTI where the kernel is mostly non-Global: */
+ if (cpu_feature_enabled(X86_FEATURE_PTI))
+ __default_kernel_pte_mask &= ~_PAGE_GLOBAL;
+
+ /* Enable 1 GB linear kernel mappings if available: */
+ if (direct_gbpages && boot_cpu_has(X86_FEATURE_GBPAGES)) {
+ printk(KERN_INFO "Using GB pages for direct mapping\n");
+ page_size_mask |= 1 << PG_LEVEL_1G;
+ } else {
+ direct_gbpages = 0;
+ }
+}
+
+static void setup_pcid(void)
+{
+ if (!IS_ENABLED(CONFIG_X86_64))
+ return;
+
+ if (!boot_cpu_has(X86_FEATURE_PCID))
+ return;
+
+ if (boot_cpu_has(X86_FEATURE_PGE)) {
+ /*
+ * This can't be cr4_set_bits_and_update_boot() -- the
+ * trampoline code can't handle CR4.PCIDE and it wouldn't
+ * do any good anyway. Despite the name,
+ * cr4_set_bits_and_update_boot() doesn't actually cause
+ * the bits in question to remain set all the way through
+ * the secondary boot asm.
+ *
+ * Instead, we brute-force it and set CR4.PCIDE manually in
+ * start_secondary().
+ */
+ cr4_set_bits(X86_CR4_PCIDE);
+
+ /*
+ * INVPCID's single-context modes (2/3) only work if we set
+ * X86_CR4_PCIDE, *and* we INVPCID support. It's unusable
+ * on systems that have X86_CR4_PCIDE clear, or that have
+ * no INVPCID support at all.
+ */
+ if (boot_cpu_has(X86_FEATURE_INVPCID))
+ setup_force_cpu_cap(X86_FEATURE_INVPCID_SINGLE);
+ } else {
+ /*
+ * flush_tlb_all(), as currently implemented, won't work if
+ * PCID is on but PGE is not. Since that combination
+ * doesn't exist on real hardware, there's no reason to try
+ * to fully support it, but it's polite to avoid corrupting
+ * data if we're on an improperly configured VM.
+ */
+ setup_clear_cpu_cap(X86_FEATURE_PCID);
+ }
+}
+
+#ifdef CONFIG_X86_32
+#define NR_RANGE_MR 3
+#else /* CONFIG_X86_64 */
+#define NR_RANGE_MR 5
+#endif
+
+static int __meminit save_mr(struct map_range *mr, int nr_range,
+ unsigned long start_pfn, unsigned long end_pfn,
+ unsigned long page_size_mask)
+{
+ if (start_pfn < end_pfn) {
+ if (nr_range >= NR_RANGE_MR)
+ panic("run out of range for init_memory_mapping\n");
+ mr[nr_range].start = start_pfn<<PAGE_SHIFT;
+ mr[nr_range].end = end_pfn<<PAGE_SHIFT;
+ mr[nr_range].page_size_mask = page_size_mask;
+ nr_range++;
+ }
+
+ return nr_range;
+}
+
+/*
+ * adjust the page_size_mask for small range to go with
+ * big page size instead small one if nearby are ram too.
+ */
+static void __ref adjust_range_page_size_mask(struct map_range *mr,
+ int nr_range)
+{
+ int i;
+
+ for (i = 0; i < nr_range; i++) {
+ if ((page_size_mask & (1<<PG_LEVEL_2M)) &&
+ !(mr[i].page_size_mask & (1<<PG_LEVEL_2M))) {
+ unsigned long start = round_down(mr[i].start, PMD_SIZE);
+ unsigned long end = round_up(mr[i].end, PMD_SIZE);
+
+#ifdef CONFIG_X86_32
+ if ((end >> PAGE_SHIFT) > max_low_pfn)
+ continue;
+#endif
+
+ if (memblock_is_region_memory(start, end - start))
+ mr[i].page_size_mask |= 1<<PG_LEVEL_2M;
+ }
+ if ((page_size_mask & (1<<PG_LEVEL_1G)) &&
+ !(mr[i].page_size_mask & (1<<PG_LEVEL_1G))) {
+ unsigned long start = round_down(mr[i].start, PUD_SIZE);
+ unsigned long end = round_up(mr[i].end, PUD_SIZE);
+
+ if (memblock_is_region_memory(start, end - start))
+ mr[i].page_size_mask |= 1<<PG_LEVEL_1G;
+ }
+ }
+}
+
+static const char *page_size_string(struct map_range *mr)
+{
+ static const char str_1g[] = "1G";
+ static const char str_2m[] = "2M";
+ static const char str_4m[] = "4M";
+ static const char str_4k[] = "4k";
+
+ if (mr->page_size_mask & (1<<PG_LEVEL_1G))
+ return str_1g;
+ /*
+ * 32-bit without PAE has a 4M large page size.
+ * PG_LEVEL_2M is misnamed, but we can at least
+ * print out the right size in the string.
+ */
+ if (IS_ENABLED(CONFIG_X86_32) &&
+ !IS_ENABLED(CONFIG_X86_PAE) &&
+ mr->page_size_mask & (1<<PG_LEVEL_2M))
+ return str_4m;
+
+ if (mr->page_size_mask & (1<<PG_LEVEL_2M))
+ return str_2m;
+
+ return str_4k;
+}
+
+static int __meminit split_mem_range(struct map_range *mr, int nr_range,
+ unsigned long start,
+ unsigned long end)
+{
+ unsigned long start_pfn, end_pfn, limit_pfn;
+ unsigned long pfn;
+ int i;
+
+ limit_pfn = PFN_DOWN(end);
+
+ /* head if not big page alignment ? */
+ pfn = start_pfn = PFN_DOWN(start);
+#ifdef CONFIG_X86_32
+ /*
+ * Don't use a large page for the first 2/4MB of memory
+ * because there are often fixed size MTRRs in there
+ * and overlapping MTRRs into large pages can cause
+ * slowdowns.
+ */
+ if (pfn == 0)
+ end_pfn = PFN_DOWN(PMD_SIZE);
+ else
+ end_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
+#else /* CONFIG_X86_64 */
+ end_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
+#endif
+ if (end_pfn > limit_pfn)
+ end_pfn = limit_pfn;
+ if (start_pfn < end_pfn) {
+ nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
+ pfn = end_pfn;
+ }
+
+ /* big page (2M) range */
+ start_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
+#ifdef CONFIG_X86_32
+ end_pfn = round_down(limit_pfn, PFN_DOWN(PMD_SIZE));
+#else /* CONFIG_X86_64 */
+ end_pfn = round_up(pfn, PFN_DOWN(PUD_SIZE));
+ if (end_pfn > round_down(limit_pfn, PFN_DOWN(PMD_SIZE)))
+ end_pfn = round_down(limit_pfn, PFN_DOWN(PMD_SIZE));
+#endif
+
+ if (start_pfn < end_pfn) {
+ nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
+ page_size_mask & (1<<PG_LEVEL_2M));
+ pfn = end_pfn;
+ }
+
+#ifdef CONFIG_X86_64
+ /* big page (1G) range */
+ start_pfn = round_up(pfn, PFN_DOWN(PUD_SIZE));
+ end_pfn = round_down(limit_pfn, PFN_DOWN(PUD_SIZE));
+ if (start_pfn < end_pfn) {
+ nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
+ page_size_mask &
+ ((1<<PG_LEVEL_2M)|(1<<PG_LEVEL_1G)));
+ pfn = end_pfn;
+ }
+
+ /* tail is not big page (1G) alignment */
+ start_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
+ end_pfn = round_down(limit_pfn, PFN_DOWN(PMD_SIZE));
+ if (start_pfn < end_pfn) {
+ nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
+ page_size_mask & (1<<PG_LEVEL_2M));
+ pfn = end_pfn;
+ }
+#endif
+
+ /* tail is not big page (2M) alignment */
+ start_pfn = pfn;
+ end_pfn = limit_pfn;
+ nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
+
+ if (!after_bootmem)
+ adjust_range_page_size_mask(mr, nr_range);
+
+ /* try to merge same page size and continuous */
+ for (i = 0; nr_range > 1 && i < nr_range - 1; i++) {
+ unsigned long old_start;
+ if (mr[i].end != mr[i+1].start ||
+ mr[i].page_size_mask != mr[i+1].page_size_mask)
+ continue;
+ /* move it */
+ old_start = mr[i].start;
+ memmove(&mr[i], &mr[i+1],
+ (nr_range - 1 - i) * sizeof(struct map_range));
+ mr[i--].start = old_start;
+ nr_range--;
+ }
+
+ for (i = 0; i < nr_range; i++)
+ pr_debug(" [mem %#010lx-%#010lx] page %s\n",
+ mr[i].start, mr[i].end - 1,
+ page_size_string(&mr[i]));
+
+ return nr_range;
+}
+
+struct range pfn_mapped[E820_MAX_ENTRIES];
+int nr_pfn_mapped;
+
+static void add_pfn_range_mapped(unsigned long start_pfn, unsigned long end_pfn)
+{
+ nr_pfn_mapped = add_range_with_merge(pfn_mapped, E820_MAX_ENTRIES,
+ nr_pfn_mapped, start_pfn, end_pfn);
+ nr_pfn_mapped = clean_sort_range(pfn_mapped, E820_MAX_ENTRIES);
+
+ max_pfn_mapped = max(max_pfn_mapped, end_pfn);
+
+ if (start_pfn < (1UL<<(32-PAGE_SHIFT)))
+ max_low_pfn_mapped = max(max_low_pfn_mapped,
+ min(end_pfn, 1UL<<(32-PAGE_SHIFT)));
+}
+
+bool pfn_range_is_mapped(unsigned long start_pfn, unsigned long end_pfn)
+{
+ int i;
+
+ for (i = 0; i < nr_pfn_mapped; i++)
+ if ((start_pfn >= pfn_mapped[i].start) &&
+ (end_pfn <= pfn_mapped[i].end))
+ return true;
+
+ return false;
+}
+
+/*
+ * Setup the direct mapping of the physical memory at PAGE_OFFSET.
+ * This runs before bootmem is initialized and gets pages directly from
+ * the physical memory. To access them they are temporarily mapped.
+ */
+unsigned long __ref init_memory_mapping(unsigned long start,
+ unsigned long end)
+{
+ struct map_range mr[NR_RANGE_MR];
+ unsigned long ret = 0;
+ int nr_range, i;
+
+ pr_debug("init_memory_mapping: [mem %#010lx-%#010lx]\n",
+ start, end - 1);
+
+ memset(mr, 0, sizeof(mr));
+ nr_range = split_mem_range(mr, 0, start, end);
+
+ for (i = 0; i < nr_range; i++)
+ ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,
+ mr[i].page_size_mask);
+
+ add_pfn_range_mapped(start >> PAGE_SHIFT, ret >> PAGE_SHIFT);
+
+ return ret >> PAGE_SHIFT;
+}
+
+/*
+ * We need to iterate through the E820 memory map and create direct mappings
+ * for only E820_TYPE_RAM and E820_KERN_RESERVED regions. We cannot simply
+ * create direct mappings for all pfns from [0 to max_low_pfn) and
+ * [4GB to max_pfn) because of possible memory holes in high addresses
+ * that cannot be marked as UC by fixed/variable range MTRRs.
+ * Depending on the alignment of E820 ranges, this may possibly result
+ * in using smaller size (i.e. 4K instead of 2M or 1G) page tables.
+ *
+ * init_mem_mapping() calls init_range_memory_mapping() with big range.
+ * That range would have hole in the middle or ends, and only ram parts
+ * will be mapped in init_range_memory_mapping().
+ */
+static unsigned long __init init_range_memory_mapping(
+ unsigned long r_start,
+ unsigned long r_end)
+{
+ unsigned long start_pfn, end_pfn;
+ unsigned long mapped_ram_size = 0;
+ int i;
+
+ for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) {
+ u64 start = clamp_val(PFN_PHYS(start_pfn), r_start, r_end);
+ u64 end = clamp_val(PFN_PHYS(end_pfn), r_start, r_end);
+ if (start >= end)
+ continue;
+
+ /*
+ * if it is overlapping with brk pgt, we need to
+ * alloc pgt buf from memblock instead.
+ */
+ can_use_brk_pgt = max(start, (u64)pgt_buf_end<<PAGE_SHIFT) >=
+ min(end, (u64)pgt_buf_top<<PAGE_SHIFT);
+ init_memory_mapping(start, end);
+ mapped_ram_size += end - start;
+ can_use_brk_pgt = true;
+ }
+
+ return mapped_ram_size;
+}
+
+static unsigned long __init get_new_step_size(unsigned long step_size)
+{
+ /*
+ * Initial mapped size is PMD_SIZE (2M).
+ * We can not set step_size to be PUD_SIZE (1G) yet.
+ * In worse case, when we cross the 1G boundary, and
+ * PG_LEVEL_2M is not set, we will need 1+1+512 pages (2M + 8k)
+ * to map 1G range with PTE. Hence we use one less than the
+ * difference of page table level shifts.
+ *
+ * Don't need to worry about overflow in the top-down case, on 32bit,
+ * when step_size is 0, round_down() returns 0 for start, and that
+ * turns it into 0x100000000ULL.
+ * In the bottom-up case, round_up(x, 0) returns 0 though too, which
+ * needs to be taken into consideration by the code below.
+ */
+ return step_size << (PMD_SHIFT - PAGE_SHIFT - 1);
+}
+
+/**
+ * memory_map_top_down - Map [map_start, map_end) top down
+ * @map_start: start address of the target memory range
+ * @map_end: end address of the target memory range
+ *
+ * This function will setup direct mapping for memory range
+ * [map_start, map_end) in top-down. That said, the page tables
+ * will be allocated at the end of the memory, and we map the
+ * memory in top-down.
+ */
+static void __init memory_map_top_down(unsigned long map_start,
+ unsigned long map_end)
+{
+ unsigned long real_end, start, last_start;
+ unsigned long step_size;
+ unsigned long addr;
+ unsigned long mapped_ram_size = 0;
+
+ /* xen has big range in reserved near end of ram, skip it at first.*/
+ addr = memblock_find_in_range(map_start, map_end, PMD_SIZE, PMD_SIZE);
+ real_end = addr + PMD_SIZE;
+
+ /* step_size need to be small so pgt_buf from BRK could cover it */
+ step_size = PMD_SIZE;
+ max_pfn_mapped = 0; /* will get exact value next */
+ min_pfn_mapped = real_end >> PAGE_SHIFT;
+ last_start = start = real_end;
+
+ /*
+ * We start from the top (end of memory) and go to the bottom.
+ * The memblock_find_in_range() gets us a block of RAM from the
+ * end of RAM in [min_pfn_mapped, max_pfn_mapped) used as new pages
+ * for page table.
+ */
+ while (last_start > map_start) {
+ if (last_start > step_size) {
+ start = round_down(last_start - 1, step_size);
+ if (start < map_start)
+ start = map_start;
+ } else
+ start = map_start;
+ mapped_ram_size += init_range_memory_mapping(start,
+ last_start);
+ last_start = start;
+ min_pfn_mapped = last_start >> PAGE_SHIFT;
+ if (mapped_ram_size >= step_size)
+ step_size = get_new_step_size(step_size);
+ }
+
+ if (real_end < map_end)
+ init_range_memory_mapping(real_end, map_end);
+}
+
+/**
+ * memory_map_bottom_up - Map [map_start, map_end) bottom up
+ * @map_start: start address of the target memory range
+ * @map_end: end address of the target memory range
+ *
+ * This function will setup direct mapping for memory range
+ * [map_start, map_end) in bottom-up. Since we have limited the
+ * bottom-up allocation above the kernel, the page tables will
+ * be allocated just above the kernel and we map the memory
+ * in [map_start, map_end) in bottom-up.
+ */
+static void __init memory_map_bottom_up(unsigned long map_start,
+ unsigned long map_end)
+{
+ unsigned long next, start;
+ unsigned long mapped_ram_size = 0;
+ /* step_size need to be small so pgt_buf from BRK could cover it */
+ unsigned long step_size = PMD_SIZE;
+
+ start = map_start;
+ min_pfn_mapped = start >> PAGE_SHIFT;
+
+ /*
+ * We start from the bottom (@map_start) and go to the top (@map_end).
+ * The memblock_find_in_range() gets us a block of RAM from the
+ * end of RAM in [min_pfn_mapped, max_pfn_mapped) used as new pages
+ * for page table.
+ */
+ while (start < map_end) {
+ if (step_size && map_end - start > step_size) {
+ next = round_up(start + 1, step_size);
+ if (next > map_end)
+ next = map_end;
+ } else {
+ next = map_end;
+ }
+
+ mapped_ram_size += init_range_memory_mapping(start, next);
+ start = next;
+
+ if (mapped_ram_size >= step_size)
+ step_size = get_new_step_size(step_size);
+ }
+}
+
+void __init init_mem_mapping(void)
+{
+ unsigned long end;
+
+ pti_check_boottime_disable();
+ probe_page_size_mask();
+ setup_pcid();
+
+#ifdef CONFIG_X86_64
+ end = max_pfn << PAGE_SHIFT;
+#else
+ end = max_low_pfn << PAGE_SHIFT;
+#endif
+
+ /* the ISA range is always mapped regardless of memory holes */
+ init_memory_mapping(0, ISA_END_ADDRESS);
+
+ /* Init the trampoline, possibly with KASLR memory offset */
+ init_trampoline();
+
+ /*
+ * If the allocation is in bottom-up direction, we setup direct mapping
+ * in bottom-up, otherwise we setup direct mapping in top-down.
+ */
+ if (memblock_bottom_up()) {
+ unsigned long kernel_end = __pa_symbol(_end);
+
+ /*
+ * we need two separate calls here. This is because we want to
+ * allocate page tables above the kernel. So we first map
+ * [kernel_end, end) to make memory above the kernel be mapped
+ * as soon as possible. And then use page tables allocated above
+ * the kernel to map [ISA_END_ADDRESS, kernel_end).
+ */
+ memory_map_bottom_up(kernel_end, end);
+ memory_map_bottom_up(ISA_END_ADDRESS, kernel_end);
+ } else {
+ memory_map_top_down(ISA_END_ADDRESS, end);
+ }
+
+#ifdef CONFIG_X86_64
+ if (max_pfn > max_low_pfn) {
+ /* can we preseve max_low_pfn ?*/
+ max_low_pfn = max_pfn;
+ }
+#else
+ early_ioremap_page_table_range_init();
+#endif
+
+ load_cr3(swapper_pg_dir);
+ __flush_tlb_all();
+
+ x86_init.hyper.init_mem_mapping();
+
+ early_memtest(0, max_pfn_mapped << PAGE_SHIFT);
+}
+
+/*
+ * devmem_is_allowed() checks to see if /dev/mem access to a certain address
+ * is valid. The argument is a physical page number.
+ *
+ * On x86, access has to be given to the first megabyte of RAM because that
+ * area traditionally contains BIOS code and data regions used by X, dosemu,
+ * and similar apps. Since they map the entire memory range, the whole range
+ * must be allowed (for mapping), but any areas that would otherwise be
+ * disallowed are flagged as being "zero filled" instead of rejected.
+ * Access has to be given to non-kernel-ram areas as well, these contain the
+ * PCI mmio resources as well as potential bios/acpi data regions.
+ */
+int devmem_is_allowed(unsigned long pagenr)
+{
+ if (region_intersects(PFN_PHYS(pagenr), PAGE_SIZE,
+ IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE)
+ != REGION_DISJOINT) {
+ /*
+ * For disallowed memory regions in the low 1MB range,
+ * request that the page be shown as all zeros.
+ */
+ if (pagenr < 256)
+ return 2;
+
+ return 0;
+ }
+
+ /*
+ * This must follow RAM test, since System RAM is considered a
+ * restricted resource under CONFIG_STRICT_IOMEM.
+ */
+ if (iomem_is_exclusive(pagenr << PAGE_SHIFT)) {
+ /* Low 1MB bypasses iomem restrictions. */
+ if (pagenr < 256)
+ return 1;
+
+ return 0;
+ }
+
+ return 1;
+}
+
+void free_init_pages(char *what, unsigned long begin, unsigned long end)
+{
+ unsigned long begin_aligned, end_aligned;
+
+ /* Make sure boundaries are page aligned */
+ begin_aligned = PAGE_ALIGN(begin);
+ end_aligned = end & PAGE_MASK;
+
+ if (WARN_ON(begin_aligned != begin || end_aligned != end)) {
+ begin = begin_aligned;
+ end = end_aligned;
+ }
+
+ if (begin >= end)
+ return;
+
+ /*
+ * If debugging page accesses then do not free this memory but
+ * mark them not present - any buggy init-section access will
+ * create a kernel page fault:
+ */
+ if (debug_pagealloc_enabled()) {
+ pr_info("debug: unmapping init [mem %#010lx-%#010lx]\n",
+ begin, end - 1);
+ set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
+ } else {
+ /*
+ * We just marked the kernel text read only above, now that
+ * we are going to free part of that, we need to make that
+ * writeable and non-executable first.
+ */
+ set_memory_nx(begin, (end - begin) >> PAGE_SHIFT);
+ set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
+
+ free_reserved_area((void *)begin, (void *)end,
+ POISON_FREE_INITMEM, what);
+ }
+}
+
+/*
+ * begin/end can be in the direct map or the "high kernel mapping"
+ * used for the kernel image only. free_init_pages() will do the
+ * right thing for either kind of address.
+ */
+void free_kernel_image_pages(void *begin, void *end)
+{
+ unsigned long begin_ul = (unsigned long)begin;
+ unsigned long end_ul = (unsigned long)end;
+ unsigned long len_pages = (end_ul - begin_ul) >> PAGE_SHIFT;
+
+
+ free_init_pages("unused kernel image", begin_ul, end_ul);
+
+ /*
+ * PTI maps some of the kernel into userspace. For performance,
+ * this includes some kernel areas that do not contain secrets.
+ * Those areas might be adjacent to the parts of the kernel image
+ * being freed, which may contain secrets. Remove the "high kernel
+ * image mapping" for these freed areas, ensuring they are not even
+ * potentially vulnerable to Meltdown regardless of the specific
+ * optimizations PTI is currently using.
+ *
+ * The "noalias" prevents unmapping the direct map alias which is
+ * needed to access the freed pages.
+ *
+ * This is only valid for 64bit kernels. 32bit has only one mapping
+ * which can't be treated in this way for obvious reasons.
+ */
+ if (IS_ENABLED(CONFIG_X86_64) && cpu_feature_enabled(X86_FEATURE_PTI))
+ set_memory_np_noalias(begin_ul, len_pages);
+}
+
+void __weak mem_encrypt_free_decrypted_mem(void) { }
+
+void __ref free_initmem(void)
+{
+ e820__reallocate_tables();
+
+ mem_encrypt_free_decrypted_mem();
+
+ free_kernel_image_pages(&__init_begin, &__init_end);
+}
+
+#ifdef CONFIG_BLK_DEV_INITRD
+void __init free_initrd_mem(unsigned long start, unsigned long end)
+{
+ /*
+ * end could be not aligned, and We can not align that,
+ * decompresser could be confused by aligned initrd_end
+ * We already reserve the end partial page before in
+ * - i386_start_kernel()
+ * - x86_64_start_kernel()
+ * - relocate_initrd()
+ * So here We can do PAGE_ALIGN() safely to get partial page to be freed
+ */
+ free_init_pages("initrd", start, PAGE_ALIGN(end));
+}
+#endif
+
+/*
+ * Calculate the precise size of the DMA zone (first 16 MB of RAM),
+ * and pass it to the MM layer - to help it set zone watermarks more
+ * accurately.
+ *
+ * Done on 64-bit systems only for the time being, although 32-bit systems
+ * might benefit from this as well.
+ */
+void __init memblock_find_dma_reserve(void)
+{
+#ifdef CONFIG_X86_64
+ u64 nr_pages = 0, nr_free_pages = 0;
+ unsigned long start_pfn, end_pfn;
+ phys_addr_t start_addr, end_addr;
+ int i;
+ u64 u;
+
+ /*
+ * Iterate over all memory ranges (free and reserved ones alike),
+ * to calculate the total number of pages in the first 16 MB of RAM:
+ */
+ nr_pages = 0;
+ for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) {
+ start_pfn = min(start_pfn, MAX_DMA_PFN);
+ end_pfn = min(end_pfn, MAX_DMA_PFN);
+
+ nr_pages += end_pfn - start_pfn;
+ }
+
+ /*
+ * Iterate over free memory ranges to calculate the number of free
+ * pages in the DMA zone, while not counting potential partial
+ * pages at the beginning or the end of the range:
+ */
+ nr_free_pages = 0;
+ for_each_free_mem_range(u, NUMA_NO_NODE, MEMBLOCK_NONE, &start_addr, &end_addr, NULL) {
+ start_pfn = min_t(unsigned long, PFN_UP(start_addr), MAX_DMA_PFN);
+ end_pfn = min_t(unsigned long, PFN_DOWN(end_addr), MAX_DMA_PFN);
+
+ if (start_pfn < end_pfn)
+ nr_free_pages += end_pfn - start_pfn;
+ }
+
+ set_dma_reserve(nr_pages - nr_free_pages);
+#endif
+}
+
+void __init zone_sizes_init(void)
+{
+ unsigned long max_zone_pfns[MAX_NR_ZONES];
+
+ memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
+
+#ifdef CONFIG_ZONE_DMA
+ max_zone_pfns[ZONE_DMA] = min(MAX_DMA_PFN, max_low_pfn);
+#endif
+#ifdef CONFIG_ZONE_DMA32
+ max_zone_pfns[ZONE_DMA32] = min(MAX_DMA32_PFN, max_low_pfn);
+#endif
+ max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
+#ifdef CONFIG_HIGHMEM
+ max_zone_pfns[ZONE_HIGHMEM] = max_pfn;
+#endif
+
+ free_area_init_nodes(max_zone_pfns);
+}
+
+__visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate) = {
+ .loaded_mm = &init_mm,
+ .next_asid = 1,
+ .cr4 = ~0UL, /* fail hard if we screw up cr4 shadow initialization */
+};
+EXPORT_PER_CPU_SYMBOL(cpu_tlbstate);
+
+void update_cache_mode_entry(unsigned entry, enum page_cache_mode cache)
+{
+ /* entry 0 MUST be WB (hardwired to speed up translations) */
+ BUG_ON(!entry && cache != _PAGE_CACHE_MODE_WB);
+
+ __cachemode2pte_tbl[cache] = __cm_idx2pte(entry);
+ __pte2cachemode_tbl[entry] = cache;
+}
+
+#ifdef CONFIG_SWAP
+unsigned long max_swapfile_size(void)
+{
+ unsigned long pages;
+
+ pages = generic_max_swapfile_size();
+
+ if (boot_cpu_has_bug(X86_BUG_L1TF)) {
+ /* Limit the swap file size to MAX_PA/2 for L1TF workaround */
+ unsigned long long l1tf_limit = l1tf_pfn_limit();
+ /*
+ * We encode swap offsets also with 3 bits below those for pfn
+ * which makes the usable limit higher.
+ */
+#if CONFIG_PGTABLE_LEVELS > 2
+ l1tf_limit <<= PAGE_SHIFT - SWP_OFFSET_FIRST_BIT;
+#endif
+ pages = min_t(unsigned long long, l1tf_limit, pages);
+ }
+ return pages;
+}
+#endif