diff options
Diffstat (limited to 'arch/um/kernel/mem.c')
| -rw-r--r-- | arch/um/kernel/mem.c | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c new file mode 100644 index 000000000..9242dc91d --- /dev/null +++ b/arch/um/kernel/mem.c @@ -0,0 +1,202 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) + */ + +#include <linux/stddef.h> +#include <linux/module.h> +#include <linux/memblock.h> +#include <linux/highmem.h> +#include <linux/mm.h> +#include <linux/swap.h> +#include <linux/slab.h> +#include <asm/fixmap.h> +#include <asm/page.h> +#include <as-layout.h> +#include <init.h> +#include <kern.h> +#include <kern_util.h> +#include <mem_user.h> +#include <os.h> + +/* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */ +unsigned long *empty_zero_page = NULL; +EXPORT_SYMBOL(empty_zero_page); + +/* + * Initialized during boot, and readonly for initializing page tables + * afterwards + */ +pgd_t swapper_pg_dir[PTRS_PER_PGD]; + +/* Initialized at boot time, and readonly after that */ +unsigned long long highmem; +EXPORT_SYMBOL(highmem); +int kmalloc_ok = 0; + +/* Used during early boot */ +static unsigned long brk_end; + +void __init mem_init(void) +{ + /* clear the zero-page */ + memset(empty_zero_page, 0, PAGE_SIZE); + + /* Map in the area just after the brk now that kmalloc is about + * to be turned on. + */ + brk_end = (unsigned long) UML_ROUND_UP(sbrk(0)); + map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0); + memblock_free(__pa(brk_end), uml_reserved - brk_end); + uml_reserved = brk_end; + + /* this will put all low memory onto the freelists */ + memblock_free_all(); + max_low_pfn = totalram_pages(); + max_pfn = max_low_pfn; + mem_init_print_info(NULL); + kmalloc_ok = 1; +} + +/* + * Create a page table and place a pointer to it in a middle page + * directory entry. + */ +static void __init one_page_table_init(pmd_t *pmd) +{ + if (pmd_none(*pmd)) { + pte_t *pte = (pte_t *) memblock_alloc_low(PAGE_SIZE, + PAGE_SIZE); + if (!pte) + panic("%s: Failed to allocate %lu bytes align=%lx\n", + __func__, PAGE_SIZE, PAGE_SIZE); + + set_pmd(pmd, __pmd(_KERNPG_TABLE + + (unsigned long) __pa(pte))); + if (pte != pte_offset_kernel(pmd, 0)) + BUG(); + } +} + +static void __init one_md_table_init(pud_t *pud) +{ +#ifdef CONFIG_3_LEVEL_PGTABLES + pmd_t *pmd_table = (pmd_t *) memblock_alloc_low(PAGE_SIZE, PAGE_SIZE); + if (!pmd_table) + panic("%s: Failed to allocate %lu bytes align=%lx\n", + __func__, PAGE_SIZE, PAGE_SIZE); + + set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table))); + if (pmd_table != pmd_offset(pud, 0)) + BUG(); +#endif +} + +static void __init fixrange_init(unsigned long start, unsigned long end, + pgd_t *pgd_base) +{ + pgd_t *pgd; + p4d_t *p4d; + pud_t *pud; + pmd_t *pmd; + int i, j; + unsigned long vaddr; + + vaddr = start; + i = pgd_index(vaddr); + j = pmd_index(vaddr); + pgd = pgd_base + i; + + for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) { + p4d = p4d_offset(pgd, vaddr); + pud = pud_offset(p4d, vaddr); + if (pud_none(*pud)) + one_md_table_init(pud); + pmd = pmd_offset(pud, vaddr); + for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) { + one_page_table_init(pmd); + vaddr += PMD_SIZE; + } + j = 0; + } +} + +static void __init fixaddr_user_init( void) +{ +#ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA + long size = FIXADDR_USER_END - FIXADDR_USER_START; + pte_t *pte; + phys_t p; + unsigned long v, vaddr = FIXADDR_USER_START; + + if (!size) + return; + + fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir); + v = (unsigned long) memblock_alloc_low(size, PAGE_SIZE); + if (!v) + panic("%s: Failed to allocate %lu bytes align=%lx\n", + __func__, size, PAGE_SIZE); + + memcpy((void *) v , (void *) FIXADDR_USER_START, size); + p = __pa(v); + for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE, + p += PAGE_SIZE) { + pte = virt_to_kpte(vaddr); + pte_set_val(*pte, p, PAGE_READONLY); + } +#endif +} + +void __init paging_init(void) +{ + unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 }; + unsigned long vaddr; + + empty_zero_page = (unsigned long *) memblock_alloc_low(PAGE_SIZE, + PAGE_SIZE); + if (!empty_zero_page) + panic("%s: Failed to allocate %lu bytes align=%lx\n", + __func__, PAGE_SIZE, PAGE_SIZE); + + max_zone_pfn[ZONE_NORMAL] = end_iomem >> PAGE_SHIFT; + free_area_init(max_zone_pfn); + + /* + * Fixed mappings, only the page table structure has to be + * created - mappings will be set by set_fixmap(): + */ + vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK; + fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir); + + fixaddr_user_init(); +} + +/* + * This can't do anything because nothing in the kernel image can be freed + * since it's not in kernel physical memory. + */ + +void free_initmem(void) +{ +} + +/* Allocate and free page tables. */ + +pgd_t *pgd_alloc(struct mm_struct *mm) +{ + pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL); + + if (pgd) { + memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t)); + memcpy(pgd + USER_PTRS_PER_PGD, + swapper_pg_dir + USER_PTRS_PER_PGD, + (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t)); + } + return pgd; +} + +void *uml_kmalloc(int size, int flags) +{ + return kmalloc(size, flags); +} |