cregit-Linux how code gets into the kernel

Release 4.15 arch/x86/include/asm/pgtable_64.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_PGTABLE_64_H

#define _ASM_X86_PGTABLE_64_H

#include <linux/const.h>
#include <asm/pgtable_64_types.h>

#ifndef __ASSEMBLY__

/*
 * This file contains the functions and defines necessary to modify and use
 * the x86-64 page table tree.
 */
#include <asm/processor.h>
#include <linux/bitops.h>
#include <linux/threads.h>

extern p4d_t level4_kernel_pgt[512];
extern p4d_t level4_ident_pgt[512];
extern pud_t level3_kernel_pgt[512];
extern pud_t level3_ident_pgt[512];
extern pmd_t level2_kernel_pgt[512];
extern pmd_t level2_fixmap_pgt[512];
extern pmd_t level2_ident_pgt[512];
extern pte_t level1_fixmap_pgt[512];
extern pgd_t init_top_pgt[];


#define swapper_pg_dir init_top_pgt

extern void paging_init(void);


#define pte_ERROR(e)					\
	pr_err("%s:%d: bad pte %p(%016lx)\n",           \
               __FILE__, __LINE__, &(e), pte_val(e))

#define pmd_ERROR(e)					\
	pr_err("%s:%d: bad pmd %p(%016lx)\n",           \
               __FILE__, __LINE__, &(e), pmd_val(e))

#define pud_ERROR(e)					\
	pr_err("%s:%d: bad pud %p(%016lx)\n",           \
               __FILE__, __LINE__, &(e), pud_val(e))

#if CONFIG_PGTABLE_LEVELS >= 5

#define p4d_ERROR(e)					\
	pr_err("%s:%d: bad p4d %p(%016lx)\n",           \
               __FILE__, __LINE__, &(e), p4d_val(e))
#endif


#define pgd_ERROR(e)					\
	pr_err("%s:%d: bad pgd %p(%016lx)\n",           \
               __FILE__, __LINE__, &(e), pgd_val(e))

struct mm_struct;

void set_pte_vaddr_p4d(p4d_t *p4d_page, unsigned long vaddr, pte_t new_pte);
void set_pte_vaddr_pud(pud_t *pud_page, unsigned long vaddr, pte_t new_pte);


static inline void native_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) { *ptep = native_make_pte(0); }

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Jeremy Fitzhardinge1553.57%150.00%
Andi Kleen1346.43%150.00%
Total28100.00%2100.00%


static inline void native_set_pte(pte_t *ptep, pte_t pte) { *ptep = pte; }

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Jeremy Fitzhardinge1578.95%150.00%
David S. Miller421.05%150.00%
Total19100.00%2100.00%


static inline void native_set_pte_atomic(pte_t *ptep, pte_t pte) { native_set_pte(ptep, pte); }

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Ingo Molnar21100.00%1100.00%
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static inline void native_set_pmd(pmd_t *pmdp, pmd_t pmd) { *pmdp = pmd; }

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Andrea Arcangeli19100.00%1100.00%
Total19100.00%1100.00%


static inline void native_pmd_clear(pmd_t *pmd) { native_set_pmd(pmd, native_make_pmd(0)); }

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Andrea Arcangeli21100.00%1100.00%
Total21100.00%1100.00%


static inline pte_t native_ptep_get_and_clear(pte_t *xp) { #ifdef CONFIG_SMP return native_make_pte(xchg(&xp->pte, 0)); #else /* native_local_ptep_get_and_clear, but duplicated because of cyclic dependency */ pte_t ret = *xp; native_pte_clear(NULL, 0, xp); return ret; #endif }

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Jeremy Fitzhardinge4180.39%133.33%
Andi Kleen917.65%133.33%
Joe Perches11.96%133.33%
Total51100.00%3100.00%


static inline pmd_t native_pmdp_get_and_clear(pmd_t *xp) { #ifdef CONFIG_SMP return native_make_pmd(xchg(&xp->pmd, 0)); #else /* native_local_pmdp_get_and_clear, but duplicated because of cyclic dependency */ pmd_t ret = *xp; native_pmd_clear(xp); return ret; #endif }

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Andrea Arcangeli3165.96%133.33%
Andi Kleen1327.66%133.33%
Jeremy Fitzhardinge36.38%133.33%
Total47100.00%3100.00%


static inline void native_set_pud(pud_t *pudp, pud_t pud) { *pudp = pud; }

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Andi Kleen1263.16%266.67%
Jeremy Fitzhardinge736.84%133.33%
Total19100.00%3100.00%


static inline void native_pud_clear(pud_t *pud) { native_set_pud(pud, native_make_pud(0)); }

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Andi Kleen1466.67%133.33%
Jeremy Fitzhardinge628.57%133.33%
Adrian Bunk14.76%133.33%
Total21100.00%3100.00%


static inline pud_t native_pudp_get_and_clear(pud_t *xp) { #ifdef CONFIG_SMP return native_make_pud(xchg(&xp->pud, 0)); #else /* native_local_pudp_get_and_clear, * but duplicated because of cyclic dependency */ pud_t ret = *xp; native_pud_clear(xp); return ret; #endif }

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Matthew Wilcox47100.00%1100.00%
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#ifdef CONFIG_PAGE_TABLE_ISOLATION /* * All top-level PAGE_TABLE_ISOLATION page tables are order-1 pages * (8k-aligned and 8k in size). The kernel one is at the beginning 4k and * the user one is in the last 4k. To switch between them, you * just need to flip the 12th bit in their addresses. */ #define PTI_PGTABLE_SWITCH_BIT PAGE_SHIFT /* * This generates better code than the inline assembly in * __set_bit(). */
static inline void *ptr_set_bit(void *ptr, int bit) { unsigned long __ptr = (unsigned long)ptr; __ptr |= BIT(bit); return (void *)__ptr; }

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static inline void *ptr_clear_bit(void *ptr, int bit) { unsigned long __ptr = (unsigned long)ptr; __ptr &= ~BIT(bit); return (void *)__ptr; }

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Dave Hansen40100.00%1100.00%
Total40100.00%1100.00%


static inline pgd_t *kernel_to_user_pgdp(pgd_t *pgdp) { return ptr_set_bit(pgdp, PTI_PGTABLE_SWITCH_BIT); }

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Dave Hansen20100.00%1100.00%
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static inline pgd_t *user_to_kernel_pgdp(pgd_t *pgdp) { return ptr_clear_bit(pgdp, PTI_PGTABLE_SWITCH_BIT); }

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Dave Hansen20100.00%1100.00%
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static inline p4d_t *kernel_to_user_p4dp(p4d_t *p4dp) { return ptr_set_bit(p4dp, PTI_PGTABLE_SWITCH_BIT); }

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Dave Hansen20100.00%1100.00%
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static inline p4d_t *user_to_kernel_p4dp(p4d_t *p4dp) { return ptr_clear_bit(p4dp, PTI_PGTABLE_SWITCH_BIT); }

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Dave Hansen20100.00%1100.00%
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#endif /* CONFIG_PAGE_TABLE_ISOLATION */ /* * Page table pages are page-aligned. The lower half of the top * level is used for userspace and the top half for the kernel. * * Returns true for parts of the PGD that map userspace and * false for the parts that map the kernel. */
static inline bool pgdp_maps_userspace(void *__ptr) { unsigned long ptr = (unsigned long)__ptr; return (ptr & ~PAGE_MASK) < (PAGE_SIZE / 2); }

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Dave Hansen35100.00%1100.00%
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#ifdef CONFIG_PAGE_TABLE_ISOLATION pgd_t __pti_set_user_pgd(pgd_t *pgdp, pgd_t pgd); /* * Take a PGD location (pgdp) and a pgd value that needs to be set there. * Populates the user and returns the resulting PGD that must be set in * the kernel copy of the page tables. */
static inline pgd_t pti_set_user_pgd(pgd_t *pgdp, pgd_t pgd) { if (!static_cpu_has(X86_FEATURE_PTI)) return pgd; return __pti_set_user_pgd(pgdp, pgd); }

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Dave Hansen33100.00%1100.00%
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#else
static inline pgd_t pti_set_user_pgd(pgd_t *pgdp, pgd_t pgd) { return pgd; }

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Dave Hansen17100.00%1100.00%
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#endif
static inline void native_set_p4d(p4d_t *p4dp, p4d_t p4d) { #if defined(CONFIG_PAGE_TABLE_ISOLATION) && !defined(CONFIG_X86_5LEVEL) p4dp->pgd = pti_set_user_pgd(&p4dp->pgd, p4d.pgd); #else *p4dp = p4d; #endif }

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Dave Hansen3262.75%150.00%
Kirill A. Shutemov1937.25%150.00%
Total51100.00%2100.00%


static inline void native_p4d_clear(p4d_t *p4d) { #ifdef CONFIG_X86_5LEVEL native_set_p4d(p4d, native_make_p4d(0)); #else native_set_p4d(p4d, (p4d_t) { .pgd = native_make_pgd(0)}); #endif }

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Kirill A. Shutemov46100.00%2100.00%
Total46100.00%2100.00%


static inline void native_set_pgd(pgd_t *pgdp, pgd_t pgd) { #ifdef CONFIG_PAGE_TABLE_ISOLATION *pgdp = pti_set_user_pgd(pgdp, pgd); #else *pgdp = pgd; #endif }

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Dave Hansen1747.22%133.33%
Zachary Amsden1130.56%133.33%
Jeremy Fitzhardinge822.22%133.33%
Total36100.00%3100.00%


static inline void native_pgd_clear(pgd_t *pgd) { native_set_pgd(pgd, native_make_pgd(0)); }

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Jeremy Fitzhardinge1676.19%150.00%
Zachary Amsden523.81%150.00%
Total21100.00%2100.00%

extern void sync_global_pgds(unsigned long start, unsigned long end); /* * Conversion functions: convert a page and protection to a page entry, * and a page entry and page directory to the page they refer to. */ /* * Level 4 access. */
static inline int pgd_large(pgd_t pgd) { return 0; }

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H. Peter Anvin13100.00%1100.00%
Total13100.00%1100.00%

#define mk_kernel_pgd(address) __pgd((address) | _KERNPG_TABLE) /* PUD - Level3 access */ /* PMD - Level 2 access */ /* PTE - Level 1 access. */ /* x86-64 always has all page tables mapped. */ #define pte_offset_map(dir, address) pte_offset_kernel((dir), (address)) #define pte_unmap(pte) ((void)(pte)) /* NOP */ /* * Encode and de-code a swap entry * * | ... | 11| 10| 9|8|7|6|5| 4| 3|2| 1|0| <- bit number * | ... |SW3|SW2|SW1|G|L|D|A|CD|WT|U| W|P| <- bit names * | OFFSET (14->63) | TYPE (9-13) |0|0|X|X| X| X|X|SD|0| <- swp entry * * G (8) is aliased and used as a PROT_NONE indicator for * !present ptes. We need to start storing swap entries above * there. We also need to avoid using A and D because of an * erratum where they can be incorrectly set by hardware on * non-present PTEs. * * SD (1) in swp entry is used to store soft dirty bit, which helps us * remember soft dirty over page migration * * Bit 7 in swp entry should be 0 because pmd_present checks not only P, * but also L and G. */ #define SWP_TYPE_FIRST_BIT (_PAGE_BIT_PROTNONE + 1) #define SWP_TYPE_BITS 5 /* Place the offset above the type: */ #define SWP_OFFSET_FIRST_BIT (SWP_TYPE_FIRST_BIT + SWP_TYPE_BITS) #define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > SWP_TYPE_BITS) #define __swp_type(x) (((x).val >> (SWP_TYPE_FIRST_BIT)) \ & ((1U << SWP_TYPE_BITS) - 1)) #define __swp_offset(x) ((x).val >> SWP_OFFSET_FIRST_BIT) #define __swp_entry(type, offset) ((swp_entry_t) { \ ((type) << (SWP_TYPE_FIRST_BIT)) \ | ((offset) << SWP_OFFSET_FIRST_BIT) }) #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val((pte)) }) #define __pmd_to_swp_entry(pmd) ((swp_entry_t) { pmd_val((pmd)) }) #define __swp_entry_to_pte(x) ((pte_t) { .pte = (x).val }) #define __swp_entry_to_pmd(x) ((pmd_t) { .pmd = (x).val }) extern int kern_addr_valid(unsigned long addr); extern void cleanup_highmap(void); #define HAVE_ARCH_UNMAPPED_AREA #define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN #define pgtable_cache_init() do { } while (0) #define check_pgt_cache() do { } while (0) #define PAGE_AGP PAGE_KERNEL_NOCACHE #define HAVE_PAGE_AGP 1 /* fs/proc/kcore.c */ #define kc_vaddr_to_offset(v) ((v) & __VIRTUAL_MASK) #define kc_offset_to_vaddr(o) ((o) | ~__VIRTUAL_MASK) #define __HAVE_ARCH_PTE_SAME #define vmemmap ((struct page *)VMEMMAP_START) extern void init_extra_mapping_uc(unsigned long phys, unsigned long size); extern void init_extra_mapping_wb(unsigned long phys, unsigned long size); #define gup_fast_permitted gup_fast_permitted
static inline bool gup_fast_permitted(unsigned long start, int nr_pages, int write) { unsigned long len, end; len = (unsigned long)nr_pages << PAGE_SHIFT; end = start + len; if (end < start) return false; if (end >> __VIRTUAL_MASK_SHIFT) return false; return true; }

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Kirill A. Shutemov60100.00%1100.00%
Total60100.00%1100.00%

#endif /* !__ASSEMBLY__ */ #endif /* _ASM_X86_PGTABLE_64_H */

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Dave Hansen33528.27%36.12%
Andi Kleen23219.58%714.29%
Kirill A. Shutemov17614.85%612.24%
Jeremy Fitzhardinge13211.14%48.16%
Andrea Arcangeli715.99%12.04%
Matthew Wilcox473.97%12.04%
Alexander Duyck302.53%12.04%
Ingo Molnar211.77%12.04%
Eduardo Pereira Habkost161.35%24.08%
H. Peter Anvin161.35%24.08%
Zachary Amsden161.35%12.04%
Zi Yan141.18%12.04%
Haicheng Li131.10%12.04%
Jan Beulich100.84%12.04%
Vivek Goyal80.68%12.04%
Andrew Morton80.68%24.08%
Joe Perches70.59%24.08%
Stefan Bader70.59%12.04%
Thomas Gleixner70.59%12.04%
Linus Torvalds60.51%24.08%
David S. Miller40.34%12.04%
Jiri Kosina30.25%12.04%
Naoya Horiguchi10.08%12.04%
Greg Kroah-Hartman10.08%12.04%
Zwane Mwaikambo10.08%12.04%
Randy Dunlap10.08%12.04%
Jiri Slaby10.08%12.04%
Adrian Bunk10.08%12.04%
Total1185100.00%49100.00%
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