arch/x86/include/asm/pgtable-3level.h - linux - Git at Google

 /* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _ASM_X86_PGTABLE_3LEVEL_H
 #define _ASM_X86_PGTABLE_3LEVEL_H

 /*
  * Intel Physical Address Extension (PAE) Mode - three-level page
  * tables on PPro+ CPUs.
  *
  * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
  */

 #define pte_ERROR(e)							\
 	pr_err("%s:%d: bad pte %p(%08lx%08lx)\n",			\
 	       __FILE__, __LINE__, &(e), (e).pte_high, (e).pte_low)
 #define pmd_ERROR(e)							\
 	pr_err("%s:%d: bad pmd %p(%016Lx)\n",				\
 	       __FILE__, __LINE__, &(e), pmd_val(e))
 #define pgd_ERROR(e)							\
 	pr_err("%s:%d: bad pgd %p(%016Lx)\n",				\
 	       __FILE__, __LINE__, &(e), pgd_val(e))

 #define pxx_xchg64(_pxx, _ptr, _val) ({					\
 	_pxx##val_t *_p = (_pxx##val_t *)_ptr;				\
 	_pxx##val_t _o = *_p;						\
 	do { } while (!try_cmpxchg64(_p, &_o, (_val)));			\
 	native_make_##_pxx(_o);						\
 })

 /*
  * Rules for using set_pte: the pte being assigned *must* be
  * either not present or in a state where the hardware will
  * not attempt to update the pte.  In places where this is
  * not possible, use pte_get_and_clear to obtain the old pte
  * value and then use set_pte to update it.  -ben
  */
 static inline void native_set_pte(pte_t *ptep, pte_t pte)
 {
 	WRITE_ONCE(ptep->pte_high, pte.pte_high);
 	smp_wmb();
 	WRITE_ONCE(ptep->pte_low, pte.pte_low);
 }

 static inline void native_set_pte_atomic(pte_t *ptep, pte_t pte)
 {
 	pxx_xchg64(pte, ptep, native_pte_val(pte));
 }

 static inline void native_set_pmd(pmd_t *pmdp, pmd_t pmd)
 {
 	pxx_xchg64(pmd, pmdp, native_pmd_val(pmd));
 }

 static inline void native_set_pud(pud_t *pudp, pud_t pud)
 {
 #ifdef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION
 	pud.p4d.pgd = pti_set_user_pgtbl(&pudp->p4d.pgd, pud.p4d.pgd);
 #endif
 	pxx_xchg64(pud, pudp, native_pud_val(pud));
 }

 /*
  * For PTEs and PDEs, we must clear the P-bit first when clearing a page table
  * entry, so clear the bottom half first and enforce ordering with a compiler
  * barrier.
  */
 static inline void native_pte_clear(struct mm_struct *mm, unsigned long addr,
 				    pte_t *ptep)
 {
 	WRITE_ONCE(ptep->pte_low, 0);
 	smp_wmb();
 	WRITE_ONCE(ptep->pte_high, 0);
 }

 static inline void native_pmd_clear(pmd_t *pmdp)
 {
 	WRITE_ONCE(pmdp->pmd_low, 0);
 	smp_wmb();
 	WRITE_ONCE(pmdp->pmd_high, 0);
 }

 static inline void native_pud_clear(pud_t *pudp)
 {
 }

 static inline void pud_clear(pud_t *pudp)
 {
 	set_pud(pudp, __pud(0));

 	/*
 	 * According to Intel App note "TLBs, Paging-Structure Caches,
 	 * and Their Invalidation", April 2007, document 317080-001,
 	 * section 8.1: in PAE mode we explicitly have to flush the
 	 * TLB via cr3 if the top-level pgd is changed...
 	 *
 	 * Currently all places where pud_clear() is called either have
 	 * flush_tlb_mm() followed or don't need TLB flush (x86_64 code or
 	 * pud_clear_bad()), so we don't need TLB flush here.
 	 */
 }


 #ifdef CONFIG_SMP
 static inline pte_t native_ptep_get_and_clear(pte_t *ptep)
 {
 	return pxx_xchg64(pte, ptep, 0ULL);
 }

 static inline pmd_t native_pmdp_get_and_clear(pmd_t *pmdp)
 {
 	return pxx_xchg64(pmd, pmdp, 0ULL);
 }

 static inline pud_t native_pudp_get_and_clear(pud_t *pudp)
 {
 	return pxx_xchg64(pud, pudp, 0ULL);
 }
 #else
 #define native_ptep_get_and_clear(xp) native_local_ptep_get_and_clear(xp)
 #define native_pmdp_get_and_clear(xp) native_local_pmdp_get_and_clear(xp)
 #define native_pudp_get_and_clear(xp) native_local_pudp_get_and_clear(xp)
 #endif

 #ifndef pmdp_establish
 #define pmdp_establish pmdp_establish
 static inline pmd_t pmdp_establish(struct vm_area_struct *vma,
 		unsigned long address, pmd_t *pmdp, pmd_t pmd)
 {
 	pmd_t old;

 	/*
 	 * If pmd has present bit cleared we can get away without expensive
 	 * cmpxchg64: we can update pmdp half-by-half without racing with
 	 * anybody.
 	 */
 	if (!(pmd_val(pmd) & _PAGE_PRESENT)) {
 		/* xchg acts as a barrier before setting of the high bits */
 		old.pmd_low = xchg(&pmdp->pmd_low, pmd.pmd_low);
 		old.pmd_high = READ_ONCE(pmdp->pmd_high);
 		WRITE_ONCE(pmdp->pmd_high, pmd.pmd_high);

 		return old;
 	}

 	return pxx_xchg64(pmd, pmdp, pmd.pmd);
 }
 #endif

 /*
  * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that
  * are !pte_none() && !pte_present().
  *
  * Format of swap PTEs:
  *
  *   6 6 6 6 5 5 5 5 5 5 5 5 5 5 4 4 4 4 4 4 4 4 4 4 3 3 3 3 3 3 3 3
  *   3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2
  *   < type -> <---------------------- offset ----------------------
  *
  *   3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
  *   1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
  *   --------------------------------------------> 0 E 0 0 0 0 0 0 0
  *
  *   E is the exclusive marker that is not stored in swap entries.
  */
 #define SWP_TYPE_BITS		5
 #define _SWP_TYPE_MASK ((1U << SWP_TYPE_BITS) - 1)

 #define SWP_OFFSET_FIRST_BIT	(_PAGE_BIT_PROTNONE + 1)

 /* We always extract/encode the offset by shifting it all the way up, and then down again */
 #define SWP_OFFSET_SHIFT	(SWP_OFFSET_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_MASK)
 #define __swp_offset(x)			((x).val >> SWP_TYPE_BITS)
 #define __swp_entry(type, offset)	((swp_entry_t){((type) & _SWP_TYPE_MASK) \
 					| (offset) << SWP_TYPE_BITS})

 /*
  * Normally, __swp_entry() converts from arch-independent swp_entry_t to
  * arch-dependent swp_entry_t, and __swp_entry_to_pte() just stores the result
  * to pte. But here we have 32bit swp_entry_t and 64bit pte, and need to use the
  * whole 64 bits. Thus, we shift the "real" arch-dependent conversion to
  * __swp_entry_to_pte() through the following helper macro based on 64bit
  * __swp_entry().
  */
 #define __swp_pteval_entry(type, offset) ((pteval_t) { \
 	(~(pteval_t)(offset) << SWP_OFFSET_SHIFT >> SWP_TYPE_BITS) \
 	| ((pteval_t)(type) << (64 - SWP_TYPE_BITS)) })

 #define __swp_entry_to_pte(x)	((pte_t){ .pte = \
 		__swp_pteval_entry(__swp_type(x), __swp_offset(x)) })
 /*
  * Analogically, __pte_to_swp_entry() doesn't just extract the arch-dependent
  * swp_entry_t, but also has to convert it from 64bit to the 32bit
  * intermediate representation, using the following macros based on 64bit
  * __swp_type() and __swp_offset().
  */
 #define __pteval_swp_type(x) ((unsigned long)((x).pte >> (64 - SWP_TYPE_BITS)))
 #define __pteval_swp_offset(x) ((unsigned long)(~((x).pte) << SWP_TYPE_BITS >> SWP_OFFSET_SHIFT))

 #define __pte_to_swp_entry(pte)	(__swp_entry(__pteval_swp_type(pte), \
 					     __pteval_swp_offset(pte)))

 /* We borrow bit 7 to store the exclusive marker in swap PTEs. */
 #define _PAGE_SWP_EXCLUSIVE	_PAGE_PSE

 #include <asm/pgtable-invert.h>

 #endif /* _ASM_X86_PGTABLE_3LEVEL_H */
	/* SPDX-License-Identifier: GPL-2.0 */
	#ifndef _ASM_X86_PGTABLE_3LEVEL_H
	#define _ASM_X86_PGTABLE_3LEVEL_H

	/*
	* Intel Physical Address Extension (PAE) Mode - three-level page
	* tables on PPro+ CPUs.
	*
	* Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
	*/

	#define pte_ERROR(e) \
	pr_err("%s:%d: bad pte %p(%08lx%08lx)\n", \
	__FILE__, __LINE__, &(e), (e).pte_high, (e).pte_low)
	#define pmd_ERROR(e) \
	pr_err("%s:%d: bad pmd %p(%016Lx)\n", \
	__FILE__, __LINE__, &(e), pmd_val(e))
	#define pgd_ERROR(e) \
	pr_err("%s:%d: bad pgd %p(%016Lx)\n", \
	__FILE__, __LINE__, &(e), pgd_val(e))

	#define pxx_xchg64(_pxx, _ptr, _val) ({ \
	_pxx##val_t _p = (_pxx##val_t )_ptr; \
	_pxx##val_t _o = *_p; \
	do { } while (!try_cmpxchg64(_p, &_o, (_val))); \
	native_make_##_pxx(_o); \
	})

	/*
	* Rules for using set_pte: the pte being assigned must be
	* either not present or in a state where the hardware will
	* not attempt to update the pte. In places where this is
	* not possible, use pte_get_and_clear to obtain the old pte
	* value and then use set_pte to update it. -ben
	*/
	static inline void native_set_pte(pte_t *ptep, pte_t pte)
	{
	WRITE_ONCE(ptep->pte_high, pte.pte_high);
	smp_wmb();
	WRITE_ONCE(ptep->pte_low, pte.pte_low);
	}

	static inline void native_set_pte_atomic(pte_t *ptep, pte_t pte)
	{
	pxx_xchg64(pte, ptep, native_pte_val(pte));
	}

	static inline void native_set_pmd(pmd_t *pmdp, pmd_t pmd)
	{
	pxx_xchg64(pmd, pmdp, native_pmd_val(pmd));
	}

	static inline void native_set_pud(pud_t *pudp, pud_t pud)
	{
	#ifdef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION
	pud.p4d.pgd = pti_set_user_pgtbl(&pudp->p4d.pgd, pud.p4d.pgd);
	#endif
	pxx_xchg64(pud, pudp, native_pud_val(pud));
	}

	/*
	* For PTEs and PDEs, we must clear the P-bit first when clearing a page table
	* entry, so clear the bottom half first and enforce ordering with a compiler
	* barrier.
	*/
	static inline void native_pte_clear(struct mm_struct *mm, unsigned long addr,
	pte_t *ptep)
	{
	WRITE_ONCE(ptep->pte_low, 0);
	smp_wmb();
	WRITE_ONCE(ptep->pte_high, 0);
	}

	static inline void native_pmd_clear(pmd_t *pmdp)
	{
	WRITE_ONCE(pmdp->pmd_low, 0);
	smp_wmb();
	WRITE_ONCE(pmdp->pmd_high, 0);
	}

	static inline void native_pud_clear(pud_t *pudp)
	{
	}

	static inline void pud_clear(pud_t *pudp)
	{
	set_pud(pudp, __pud(0));

	/*
	* According to Intel App note "TLBs, Paging-Structure Caches,
	* and Their Invalidation", April 2007, document 317080-001,
	* section 8.1: in PAE mode we explicitly have to flush the
	* TLB via cr3 if the top-level pgd is changed...
	*
	* Currently all places where pud_clear() is called either have
	* flush_tlb_mm() followed or don't need TLB flush (x86_64 code or
	* pud_clear_bad()), so we don't need TLB flush here.
	*/
	}


	#ifdef CONFIG_SMP
	static inline pte_t native_ptep_get_and_clear(pte_t *ptep)
	{
	return pxx_xchg64(pte, ptep, 0ULL);
	}

	static inline pmd_t native_pmdp_get_and_clear(pmd_t *pmdp)
	{
	return pxx_xchg64(pmd, pmdp, 0ULL);
	}

	static inline pud_t native_pudp_get_and_clear(pud_t *pudp)
	{
	return pxx_xchg64(pud, pudp, 0ULL);
	}
	#else
	#define native_ptep_get_and_clear(xp) native_local_ptep_get_and_clear(xp)
	#define native_pmdp_get_and_clear(xp) native_local_pmdp_get_and_clear(xp)
	#define native_pudp_get_and_clear(xp) native_local_pudp_get_and_clear(xp)
	#endif

	#ifndef pmdp_establish
	#define pmdp_establish pmdp_establish
	static inline pmd_t pmdp_establish(struct vm_area_struct *vma,
	unsigned long address, pmd_t *pmdp, pmd_t pmd)
	{
	pmd_t old;

	/*
	* If pmd has present bit cleared we can get away without expensive
	* cmpxchg64: we can update pmdp half-by-half without racing with
	* anybody.
	*/
	if (!(pmd_val(pmd) & _PAGE_PRESENT)) {
	/* xchg acts as a barrier before setting of the high bits */
	old.pmd_low = xchg(&pmdp->pmd_low, pmd.pmd_low);
	old.pmd_high = READ_ONCE(pmdp->pmd_high);
	WRITE_ONCE(pmdp->pmd_high, pmd.pmd_high);

	return old;
	}

	return pxx_xchg64(pmd, pmdp, pmd.pmd);
	}
	#endif

	/*
	* Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that
	* are !pte_none() && !pte_present().
	*
	* Format of swap PTEs:
	*
	* 6 6 6 6 5 5 5 5 5 5 5 5 5 5 4 4 4 4 4 4 4 4 4 4 3 3 3 3 3 3 3 3
	* 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2
	* < type -> <---------------------- offset ----------------------
	*
	* 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
	* 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
	* --------------------------------------------> 0 E 0 0 0 0 0 0 0
	*
	* E is the exclusive marker that is not stored in swap entries.
	*/
	#define SWP_TYPE_BITS 5
	#define _SWP_TYPE_MASK ((1U << SWP_TYPE_BITS) - 1)

	#define SWP_OFFSET_FIRST_BIT (_PAGE_BIT_PROTNONE + 1)

	/* We always extract/encode the offset by shifting it all the way up, and then down again */
	#define SWP_OFFSET_SHIFT (SWP_OFFSET_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_MASK)
	#define __swp_offset(x) ((x).val >> SWP_TYPE_BITS)
	#define __swp_entry(type, offset) ((swp_entry_t){((type) & _SWP_TYPE_MASK) \
	\| (offset) << SWP_TYPE_BITS})

	/*
	* Normally, __swp_entry() converts from arch-independent swp_entry_t to
	* arch-dependent swp_entry_t, and __swp_entry_to_pte() just stores the result
	* to pte. But here we have 32bit swp_entry_t and 64bit pte, and need to use the
	* whole 64 bits. Thus, we shift the "real" arch-dependent conversion to
	* __swp_entry_to_pte() through the following helper macro based on 64bit
	* __swp_entry().
	*/
	#define __swp_pteval_entry(type, offset) ((pteval_t) { \
	(~(pteval_t)(offset) << SWP_OFFSET_SHIFT >> SWP_TYPE_BITS) \
	\| ((pteval_t)(type) << (64 - SWP_TYPE_BITS)) })

	#define __swp_entry_to_pte(x) ((pte_t){ .pte = \
	__swp_pteval_entry(__swp_type(x), __swp_offset(x)) })
	/*
	* Analogically, __pte_to_swp_entry() doesn't just extract the arch-dependent
	* swp_entry_t, but also has to convert it from 64bit to the 32bit
	* intermediate representation, using the following macros based on 64bit
	* __swp_type() and __swp_offset().
	*/
	#define __pteval_swp_type(x) ((unsigned long)((x).pte >> (64 - SWP_TYPE_BITS)))
	#define __pteval_swp_offset(x) ((unsigned long)(~((x).pte) << SWP_TYPE_BITS >> SWP_OFFSET_SHIFT))

	#define __pte_to_swp_entry(pte) (__swp_entry(__pteval_swp_type(pte), \
	__pteval_swp_offset(pte)))

	/* We borrow bit 7 to store the exclusive marker in swap PTEs. */
	#define _PAGE_SWP_EXCLUSIVE _PAGE_PSE

	#include <asm/pgtable-invert.h>

	#endif /* _ASM_X86_PGTABLE_3LEVEL_H */