292 lines
7.4 KiB
C
292 lines
7.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/sched/task.h>
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#include <linux/pgtable.h>
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#include <asm/pgalloc.h>
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#include <asm/facility.h>
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#include <asm/sections.h>
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#include <asm/mem_detect.h>
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#include <asm/maccess.h>
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#include <asm/abs_lowcore.h>
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#include "decompressor.h"
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#include "boot.h"
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#ifdef CONFIG_PROC_FS
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atomic_long_t __bootdata_preserved(direct_pages_count[PG_DIRECT_MAP_MAX]);
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#endif
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#define init_mm (*(struct mm_struct *)vmlinux.init_mm_off)
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#define swapper_pg_dir vmlinux.swapper_pg_dir_off
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#define invalid_pg_dir vmlinux.invalid_pg_dir_off
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/*
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* Mimic virt_to_kpte() in lack of init_mm symbol. Skip pmd NULL check though.
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*/
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static inline pte_t *__virt_to_kpte(unsigned long va)
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{
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return pte_offset_kernel(pmd_offset(pud_offset(p4d_offset(pgd_offset_k(va), va), va), va), va);
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}
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unsigned long __bootdata_preserved(s390_invalid_asce);
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unsigned long __bootdata(pgalloc_pos);
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unsigned long __bootdata(pgalloc_end);
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unsigned long __bootdata(pgalloc_low);
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enum populate_mode {
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POPULATE_NONE,
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POPULATE_DIRECT,
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POPULATE_ABS_LOWCORE,
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};
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static void boot_check_oom(void)
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{
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if (pgalloc_pos < pgalloc_low)
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error("out of memory on boot\n");
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}
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static void pgtable_populate_init(void)
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{
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unsigned long initrd_end;
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unsigned long kernel_end;
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kernel_end = vmlinux.default_lma + vmlinux.image_size + vmlinux.bss_size;
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pgalloc_low = round_up(kernel_end, PAGE_SIZE);
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if (IS_ENABLED(CONFIG_BLK_DEV_INITRD)) {
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initrd_end = round_up(initrd_data.start + initrd_data.size, _SEGMENT_SIZE);
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pgalloc_low = max(pgalloc_low, initrd_end);
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}
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pgalloc_end = round_down(get_mem_detect_end(), PAGE_SIZE);
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pgalloc_pos = pgalloc_end;
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boot_check_oom();
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}
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static void *boot_alloc_pages(unsigned int order)
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{
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unsigned long size = PAGE_SIZE << order;
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pgalloc_pos -= size;
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pgalloc_pos = round_down(pgalloc_pos, size);
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boot_check_oom();
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return (void *)pgalloc_pos;
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}
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static void *boot_crst_alloc(unsigned long val)
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{
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unsigned long *table;
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table = boot_alloc_pages(CRST_ALLOC_ORDER);
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if (table)
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crst_table_init(table, val);
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return table;
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}
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static pte_t *boot_pte_alloc(void)
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{
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static void *pte_leftover;
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pte_t *pte;
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BUILD_BUG_ON(_PAGE_TABLE_SIZE * 2 != PAGE_SIZE);
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if (!pte_leftover) {
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pte_leftover = boot_alloc_pages(0);
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pte = pte_leftover + _PAGE_TABLE_SIZE;
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} else {
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pte = pte_leftover;
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pte_leftover = NULL;
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}
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memset64((u64 *)pte, _PAGE_INVALID, PTRS_PER_PTE);
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return pte;
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}
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static unsigned long _pa(unsigned long addr, enum populate_mode mode)
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{
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switch (mode) {
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case POPULATE_NONE:
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return -1;
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case POPULATE_DIRECT:
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return addr;
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case POPULATE_ABS_LOWCORE:
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return __abs_lowcore_pa(addr);
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default:
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return -1;
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}
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}
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static bool can_large_pud(pud_t *pu_dir, unsigned long addr, unsigned long end)
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{
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return machine.has_edat2 &&
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IS_ALIGNED(addr, PUD_SIZE) && (end - addr) >= PUD_SIZE;
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}
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static bool can_large_pmd(pmd_t *pm_dir, unsigned long addr, unsigned long end)
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{
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return machine.has_edat1 &&
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IS_ALIGNED(addr, PMD_SIZE) && (end - addr) >= PMD_SIZE;
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}
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static void pgtable_pte_populate(pmd_t *pmd, unsigned long addr, unsigned long end,
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enum populate_mode mode)
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{
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unsigned long pages = 0;
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pte_t *pte, entry;
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pte = pte_offset_kernel(pmd, addr);
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for (; addr < end; addr += PAGE_SIZE, pte++) {
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if (pte_none(*pte)) {
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entry = __pte(_pa(addr, mode));
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entry = set_pte_bit(entry, PAGE_KERNEL_EXEC);
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set_pte(pte, entry);
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pages++;
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}
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}
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if (mode == POPULATE_DIRECT)
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update_page_count(PG_DIRECT_MAP_4K, pages);
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}
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static void pgtable_pmd_populate(pud_t *pud, unsigned long addr, unsigned long end,
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enum populate_mode mode)
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{
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unsigned long next, pages = 0;
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pmd_t *pmd, entry;
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pte_t *pte;
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pmd = pmd_offset(pud, addr);
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for (; addr < end; addr = next, pmd++) {
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next = pmd_addr_end(addr, end);
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if (pmd_none(*pmd)) {
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if (can_large_pmd(pmd, addr, next)) {
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entry = __pmd(_pa(addr, mode));
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entry = set_pmd_bit(entry, SEGMENT_KERNEL_EXEC);
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set_pmd(pmd, entry);
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pages++;
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continue;
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}
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pte = boot_pte_alloc();
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pmd_populate(&init_mm, pmd, pte);
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} else if (pmd_large(*pmd)) {
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continue;
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}
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pgtable_pte_populate(pmd, addr, next, mode);
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}
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if (mode == POPULATE_DIRECT)
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update_page_count(PG_DIRECT_MAP_1M, pages);
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}
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static void pgtable_pud_populate(p4d_t *p4d, unsigned long addr, unsigned long end,
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enum populate_mode mode)
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{
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unsigned long next, pages = 0;
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pud_t *pud, entry;
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pmd_t *pmd;
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pud = pud_offset(p4d, addr);
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for (; addr < end; addr = next, pud++) {
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next = pud_addr_end(addr, end);
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if (pud_none(*pud)) {
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if (can_large_pud(pud, addr, next)) {
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entry = __pud(_pa(addr, mode));
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entry = set_pud_bit(entry, REGION3_KERNEL_EXEC);
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set_pud(pud, entry);
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pages++;
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continue;
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}
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pmd = boot_crst_alloc(_SEGMENT_ENTRY_EMPTY);
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pud_populate(&init_mm, pud, pmd);
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} else if (pud_large(*pud)) {
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continue;
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}
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pgtable_pmd_populate(pud, addr, next, mode);
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}
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if (mode == POPULATE_DIRECT)
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update_page_count(PG_DIRECT_MAP_2G, pages);
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}
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static void pgtable_p4d_populate(pgd_t *pgd, unsigned long addr, unsigned long end,
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enum populate_mode mode)
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{
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unsigned long next;
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p4d_t *p4d;
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pud_t *pud;
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p4d = p4d_offset(pgd, addr);
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for (; addr < end; addr = next, p4d++) {
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next = p4d_addr_end(addr, end);
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if (p4d_none(*p4d)) {
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pud = boot_crst_alloc(_REGION3_ENTRY_EMPTY);
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p4d_populate(&init_mm, p4d, pud);
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}
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pgtable_pud_populate(p4d, addr, next, mode);
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}
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}
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static void pgtable_populate(unsigned long addr, unsigned long end, enum populate_mode mode)
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{
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unsigned long next;
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pgd_t *pgd;
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p4d_t *p4d;
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pgd = pgd_offset(&init_mm, addr);
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for (; addr < end; addr = next, pgd++) {
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next = pgd_addr_end(addr, end);
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if (pgd_none(*pgd)) {
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p4d = boot_crst_alloc(_REGION2_ENTRY_EMPTY);
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pgd_populate(&init_mm, pgd, p4d);
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}
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pgtable_p4d_populate(pgd, addr, next, mode);
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}
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}
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void setup_vmem(unsigned long asce_limit)
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{
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unsigned long start, end;
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unsigned long asce_type;
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unsigned long asce_bits;
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int i;
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if (asce_limit == _REGION1_SIZE) {
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asce_type = _REGION2_ENTRY_EMPTY;
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asce_bits = _ASCE_TYPE_REGION2 | _ASCE_TABLE_LENGTH;
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} else {
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asce_type = _REGION3_ENTRY_EMPTY;
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asce_bits = _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH;
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}
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s390_invalid_asce = invalid_pg_dir | _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH;
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crst_table_init((unsigned long *)swapper_pg_dir, asce_type);
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crst_table_init((unsigned long *)invalid_pg_dir, _REGION3_ENTRY_EMPTY);
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/*
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* To allow prefixing the lowcore must be mapped with 4KB pages.
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* To prevent creation of a large page at address 0 first map
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* the lowcore and create the identity mapping only afterwards.
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*/
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pgtable_populate_init();
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pgtable_populate(0, sizeof(struct lowcore), POPULATE_DIRECT);
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for_each_mem_detect_usable_block(i, &start, &end)
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pgtable_populate(start, end, POPULATE_DIRECT);
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pgtable_populate(__abs_lowcore, __abs_lowcore + sizeof(struct lowcore),
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POPULATE_ABS_LOWCORE);
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pgtable_populate(__memcpy_real_area, __memcpy_real_area + PAGE_SIZE,
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POPULATE_NONE);
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memcpy_real_ptep = __virt_to_kpte(__memcpy_real_area);
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S390_lowcore.kernel_asce = swapper_pg_dir | asce_bits;
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S390_lowcore.user_asce = s390_invalid_asce;
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__ctl_load(S390_lowcore.kernel_asce, 1, 1);
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__ctl_load(S390_lowcore.user_asce, 7, 7);
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__ctl_load(S390_lowcore.kernel_asce, 13, 13);
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init_mm.context.asce = S390_lowcore.kernel_asce;
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}
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unsigned long vmem_estimate_memory_needs(unsigned long online_mem_total)
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{
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unsigned long pages = DIV_ROUND_UP(online_mem_total, PAGE_SIZE);
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return DIV_ROUND_UP(pages, _PAGE_ENTRIES) * _PAGE_TABLE_SIZE * 2;
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}
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