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427 lines
12 KiB
427 lines
12 KiB
// SPDX-License-Identifier: GPL-2.0 |
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#include <linux/kasan.h> |
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#include <linux/sched/task.h> |
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#include <linux/memblock.h> |
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#include <linux/pgtable.h> |
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#include <asm/pgalloc.h> |
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#include <asm/kasan.h> |
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#include <asm/mem_detect.h> |
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#include <asm/processor.h> |
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#include <asm/sclp.h> |
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#include <asm/facility.h> |
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#include <asm/sections.h> |
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#include <asm/setup.h> |
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#include <asm/uv.h> |
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unsigned long kasan_vmax; |
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static unsigned long segment_pos __initdata; |
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static unsigned long segment_low __initdata; |
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static unsigned long pgalloc_pos __initdata; |
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static unsigned long pgalloc_low __initdata; |
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static unsigned long pgalloc_freeable __initdata; |
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static bool has_edat __initdata; |
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static bool has_nx __initdata; |
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#define __sha(x) ((unsigned long)kasan_mem_to_shadow((void *)x)) |
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static pgd_t early_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE); |
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static void __init kasan_early_panic(const char *reason) |
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{ |
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sclp_early_printk("The Linux kernel failed to boot with the KernelAddressSanitizer:\n"); |
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sclp_early_printk(reason); |
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disabled_wait(); |
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} |
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static void * __init kasan_early_alloc_segment(void) |
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{ |
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segment_pos -= _SEGMENT_SIZE; |
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if (segment_pos < segment_low) |
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kasan_early_panic("out of memory during initialisation\n"); |
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return (void *)segment_pos; |
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} |
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static void * __init kasan_early_alloc_pages(unsigned int order) |
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{ |
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pgalloc_pos -= (PAGE_SIZE << order); |
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if (pgalloc_pos < pgalloc_low) |
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kasan_early_panic("out of memory during initialisation\n"); |
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return (void *)pgalloc_pos; |
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} |
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static void * __init kasan_early_crst_alloc(unsigned long val) |
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{ |
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unsigned long *table; |
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table = kasan_early_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 * __init kasan_early_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 = kasan_early_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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enum populate_mode { |
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POPULATE_ONE2ONE, |
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POPULATE_MAP, |
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POPULATE_ZERO_SHADOW, |
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POPULATE_SHALLOW |
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}; |
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static void __init kasan_early_pgtable_populate(unsigned long address, |
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unsigned long end, |
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enum populate_mode mode) |
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{ |
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unsigned long pgt_prot_zero, pgt_prot, sgt_prot; |
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pgd_t *pg_dir; |
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p4d_t *p4_dir; |
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pud_t *pu_dir; |
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pmd_t *pm_dir; |
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pte_t *pt_dir; |
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pgt_prot_zero = pgprot_val(PAGE_KERNEL_RO); |
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if (!has_nx) |
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pgt_prot_zero &= ~_PAGE_NOEXEC; |
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pgt_prot = pgprot_val(PAGE_KERNEL); |
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sgt_prot = pgprot_val(SEGMENT_KERNEL); |
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if (!has_nx || mode == POPULATE_ONE2ONE) { |
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pgt_prot &= ~_PAGE_NOEXEC; |
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sgt_prot &= ~_SEGMENT_ENTRY_NOEXEC; |
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} |
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while (address < end) { |
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pg_dir = pgd_offset_k(address); |
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if (pgd_none(*pg_dir)) { |
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if (mode == POPULATE_ZERO_SHADOW && |
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IS_ALIGNED(address, PGDIR_SIZE) && |
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end - address >= PGDIR_SIZE) { |
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pgd_populate(&init_mm, pg_dir, |
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kasan_early_shadow_p4d); |
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address = (address + PGDIR_SIZE) & PGDIR_MASK; |
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continue; |
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} |
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p4_dir = kasan_early_crst_alloc(_REGION2_ENTRY_EMPTY); |
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pgd_populate(&init_mm, pg_dir, p4_dir); |
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} |
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if (mode == POPULATE_SHALLOW) { |
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address = (address + P4D_SIZE) & P4D_MASK; |
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continue; |
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} |
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p4_dir = p4d_offset(pg_dir, address); |
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if (p4d_none(*p4_dir)) { |
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if (mode == POPULATE_ZERO_SHADOW && |
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IS_ALIGNED(address, P4D_SIZE) && |
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end - address >= P4D_SIZE) { |
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p4d_populate(&init_mm, p4_dir, |
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kasan_early_shadow_pud); |
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address = (address + P4D_SIZE) & P4D_MASK; |
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continue; |
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} |
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pu_dir = kasan_early_crst_alloc(_REGION3_ENTRY_EMPTY); |
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p4d_populate(&init_mm, p4_dir, pu_dir); |
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} |
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pu_dir = pud_offset(p4_dir, address); |
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if (pud_none(*pu_dir)) { |
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if (mode == POPULATE_ZERO_SHADOW && |
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IS_ALIGNED(address, PUD_SIZE) && |
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end - address >= PUD_SIZE) { |
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pud_populate(&init_mm, pu_dir, |
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kasan_early_shadow_pmd); |
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address = (address + PUD_SIZE) & PUD_MASK; |
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continue; |
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} |
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pm_dir = kasan_early_crst_alloc(_SEGMENT_ENTRY_EMPTY); |
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pud_populate(&init_mm, pu_dir, pm_dir); |
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} |
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pm_dir = pmd_offset(pu_dir, address); |
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if (pmd_none(*pm_dir)) { |
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if (mode == POPULATE_ZERO_SHADOW && |
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IS_ALIGNED(address, PMD_SIZE) && |
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end - address >= PMD_SIZE) { |
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pmd_populate(&init_mm, pm_dir, |
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kasan_early_shadow_pte); |
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address = (address + PMD_SIZE) & PMD_MASK; |
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continue; |
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} |
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/* the first megabyte of 1:1 is mapped with 4k pages */ |
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if (has_edat && address && end - address >= PMD_SIZE && |
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mode != POPULATE_ZERO_SHADOW) { |
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void *page; |
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if (mode == POPULATE_ONE2ONE) { |
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page = (void *)address; |
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} else { |
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page = kasan_early_alloc_segment(); |
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memset(page, 0, _SEGMENT_SIZE); |
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} |
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pmd_val(*pm_dir) = __pa(page) | sgt_prot; |
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address = (address + PMD_SIZE) & PMD_MASK; |
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continue; |
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} |
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pt_dir = kasan_early_pte_alloc(); |
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pmd_populate(&init_mm, pm_dir, pt_dir); |
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} else if (pmd_large(*pm_dir)) { |
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address = (address + PMD_SIZE) & PMD_MASK; |
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continue; |
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} |
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pt_dir = pte_offset_kernel(pm_dir, address); |
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if (pte_none(*pt_dir)) { |
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void *page; |
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switch (mode) { |
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case POPULATE_ONE2ONE: |
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page = (void *)address; |
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pte_val(*pt_dir) = __pa(page) | pgt_prot; |
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break; |
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case POPULATE_MAP: |
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page = kasan_early_alloc_pages(0); |
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memset(page, 0, PAGE_SIZE); |
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pte_val(*pt_dir) = __pa(page) | pgt_prot; |
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break; |
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case POPULATE_ZERO_SHADOW: |
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page = kasan_early_shadow_page; |
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pte_val(*pt_dir) = __pa(page) | pgt_prot_zero; |
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break; |
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case POPULATE_SHALLOW: |
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/* should never happen */ |
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break; |
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} |
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} |
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address += PAGE_SIZE; |
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} |
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} |
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static void __init kasan_set_pgd(pgd_t *pgd, unsigned long asce_type) |
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{ |
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unsigned long asce_bits; |
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asce_bits = asce_type | _ASCE_TABLE_LENGTH; |
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S390_lowcore.kernel_asce = (__pa(pgd) & PAGE_MASK) | asce_bits; |
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S390_lowcore.user_asce = S390_lowcore.kernel_asce; |
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__ctl_load(S390_lowcore.kernel_asce, 1, 1); |
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__ctl_load(S390_lowcore.kernel_asce, 7, 7); |
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__ctl_load(S390_lowcore.kernel_asce, 13, 13); |
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} |
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static void __init kasan_enable_dat(void) |
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{ |
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psw_t psw; |
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psw.mask = __extract_psw(); |
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psw_bits(psw).dat = 1; |
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psw_bits(psw).as = PSW_BITS_AS_HOME; |
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__load_psw_mask(psw.mask); |
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} |
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static void __init kasan_early_detect_facilities(void) |
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{ |
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if (test_facility(8)) { |
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has_edat = true; |
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__ctl_set_bit(0, 23); |
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} |
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if (!noexec_disabled && test_facility(130)) { |
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has_nx = true; |
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__ctl_set_bit(0, 20); |
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} |
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} |
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static bool __init has_uv_sec_stor_limit(void) |
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{ |
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/* |
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* keep these conditions in line with setup_uv() |
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*/ |
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if (!is_prot_virt_host()) |
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return false; |
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if (is_prot_virt_guest()) |
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return false; |
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if (!test_facility(158)) |
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return false; |
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return !!uv_info.max_sec_stor_addr; |
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} |
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void __init kasan_early_init(void) |
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{ |
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unsigned long untracked_mem_end; |
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unsigned long shadow_alloc_size; |
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unsigned long vmax_unlimited; |
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unsigned long initrd_end; |
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unsigned long memsize; |
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unsigned long pgt_prot = pgprot_val(PAGE_KERNEL_RO); |
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pte_t pte_z; |
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pmd_t pmd_z = __pmd(__pa(kasan_early_shadow_pte) | _SEGMENT_ENTRY); |
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pud_t pud_z = __pud(__pa(kasan_early_shadow_pmd) | _REGION3_ENTRY); |
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p4d_t p4d_z = __p4d(__pa(kasan_early_shadow_pud) | _REGION2_ENTRY); |
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kasan_early_detect_facilities(); |
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if (!has_nx) |
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pgt_prot &= ~_PAGE_NOEXEC; |
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pte_z = __pte(__pa(kasan_early_shadow_page) | pgt_prot); |
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memsize = get_mem_detect_end(); |
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if (!memsize) |
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kasan_early_panic("cannot detect physical memory size\n"); |
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/* |
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* Kasan currently supports standby memory but only if it follows |
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* online memory (default allocation), i.e. no memory holes. |
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* - memsize represents end of online memory |
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* - ident_map_size represents online + standby and memory limits |
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* accounted. |
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* Kasan maps "memsize" right away. |
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* [0, memsize] - as identity mapping |
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* [__sha(0), __sha(memsize)] - shadow memory for identity mapping |
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* The rest [memsize, ident_map_size] if memsize < ident_map_size |
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* could be mapped/unmapped dynamically later during memory hotplug. |
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*/ |
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memsize = min(memsize, ident_map_size); |
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BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, P4D_SIZE)); |
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BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, P4D_SIZE)); |
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crst_table_init((unsigned long *)early_pg_dir, _REGION2_ENTRY_EMPTY); |
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untracked_mem_end = kasan_vmax = vmax_unlimited = _REGION1_SIZE; |
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if (has_uv_sec_stor_limit()) |
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kasan_vmax = min(vmax_unlimited, uv_info.max_sec_stor_addr); |
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/* init kasan zero shadow */ |
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crst_table_init((unsigned long *)kasan_early_shadow_p4d, |
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p4d_val(p4d_z)); |
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crst_table_init((unsigned long *)kasan_early_shadow_pud, |
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pud_val(pud_z)); |
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crst_table_init((unsigned long *)kasan_early_shadow_pmd, |
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pmd_val(pmd_z)); |
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memset64((u64 *)kasan_early_shadow_pte, pte_val(pte_z), PTRS_PER_PTE); |
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shadow_alloc_size = memsize >> KASAN_SHADOW_SCALE_SHIFT; |
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pgalloc_low = round_up((unsigned long)_end, _SEGMENT_SIZE); |
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if (IS_ENABLED(CONFIG_BLK_DEV_INITRD)) { |
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initrd_end = |
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round_up(INITRD_START + INITRD_SIZE, _SEGMENT_SIZE); |
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pgalloc_low = max(pgalloc_low, initrd_end); |
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} |
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if (pgalloc_low + shadow_alloc_size > memsize) |
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kasan_early_panic("out of memory during initialisation\n"); |
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if (has_edat) { |
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segment_pos = round_down(memsize, _SEGMENT_SIZE); |
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segment_low = segment_pos - shadow_alloc_size; |
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pgalloc_pos = segment_low; |
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} else { |
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pgalloc_pos = memsize; |
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} |
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init_mm.pgd = early_pg_dir; |
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/* |
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* Current memory layout: |
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* +- 0 -------------+ +- shadow start -+ |
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* | 1:1 ram mapping | /| 1/8 ram | |
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* | | / | | |
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* +- end of ram ----+ / +----------------+ |
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* | ... gap ... | / | | |
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* | |/ | kasan | |
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* +- shadow start --+ | zero | |
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* | 1/8 addr space | | page | |
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* +- shadow end -+ | mapping | |
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* | ... gap ... |\ | (untracked) | |
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* +- vmalloc area -+ \ | | |
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* | vmalloc_size | \ | | |
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* +- modules vaddr -+ \ +----------------+ |
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* | 2Gb | \| unmapped | allocated per module |
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* +-----------------+ +- shadow end ---+ |
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* |
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* Current memory layout (KASAN_VMALLOC): |
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* +- 0 -------------+ +- shadow start -+ |
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* | 1:1 ram mapping | /| 1/8 ram | |
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* | | / | | |
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* +- end of ram ----+ / +----------------+ |
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* | ... gap ... | / | kasan | |
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* | |/ | zero | |
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* +- shadow start --+ | page | |
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* | 1/8 addr space | | mapping | |
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* +- shadow end -+ | (untracked) | |
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* | ... gap ... |\ | | |
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* +- vmalloc area -+ \ +- vmalloc area -+ |
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* | vmalloc_size | \ |shallow populate| |
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* +- modules vaddr -+ \ +- modules area -+ |
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* | 2Gb | \|shallow populate| |
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* +-----------------+ +- shadow end ---+ |
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*/ |
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/* populate kasan shadow (for identity mapping and zero page mapping) */ |
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kasan_early_pgtable_populate(__sha(0), __sha(memsize), POPULATE_MAP); |
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if (IS_ENABLED(CONFIG_MODULES)) |
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untracked_mem_end = kasan_vmax - MODULES_LEN; |
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if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) { |
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untracked_mem_end = kasan_vmax - vmalloc_size - MODULES_LEN; |
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/* shallowly populate kasan shadow for vmalloc and modules */ |
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kasan_early_pgtable_populate(__sha(untracked_mem_end), __sha(kasan_vmax), |
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POPULATE_SHALLOW); |
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} |
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/* populate kasan shadow for untracked memory */ |
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kasan_early_pgtable_populate(__sha(ident_map_size), __sha(untracked_mem_end), |
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POPULATE_ZERO_SHADOW); |
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kasan_early_pgtable_populate(__sha(kasan_vmax), __sha(vmax_unlimited), |
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POPULATE_ZERO_SHADOW); |
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/* memory allocated for identity mapping structs will be freed later */ |
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pgalloc_freeable = pgalloc_pos; |
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/* populate identity mapping */ |
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kasan_early_pgtable_populate(0, memsize, POPULATE_ONE2ONE); |
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kasan_set_pgd(early_pg_dir, _ASCE_TYPE_REGION2); |
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kasan_enable_dat(); |
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/* enable kasan */ |
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init_task.kasan_depth = 0; |
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memblock_reserve(pgalloc_pos, memsize - pgalloc_pos); |
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sclp_early_printk("KernelAddressSanitizer initialized\n"); |
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} |
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void __init kasan_copy_shadow_mapping(void) |
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{ |
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/* |
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* At this point we are still running on early pages setup early_pg_dir, |
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* while swapper_pg_dir has just been initialized with identity mapping. |
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* Carry over shadow memory region from early_pg_dir to swapper_pg_dir. |
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*/ |
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pgd_t *pg_dir_src; |
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pgd_t *pg_dir_dst; |
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p4d_t *p4_dir_src; |
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p4d_t *p4_dir_dst; |
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pg_dir_src = pgd_offset_raw(early_pg_dir, KASAN_SHADOW_START); |
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pg_dir_dst = pgd_offset_raw(init_mm.pgd, KASAN_SHADOW_START); |
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p4_dir_src = p4d_offset(pg_dir_src, KASAN_SHADOW_START); |
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p4_dir_dst = p4d_offset(pg_dir_dst, KASAN_SHADOW_START); |
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memcpy(p4_dir_dst, p4_dir_src, |
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(KASAN_SHADOW_SIZE >> P4D_SHIFT) * sizeof(p4d_t)); |
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} |
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void __init kasan_free_early_identity(void) |
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{ |
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memblock_free(pgalloc_pos, pgalloc_freeable - pgalloc_pos); |
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}
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