/* SPDX-License-Identifier: GPL-2.0 */#ifndef _ASM_PGALLOC_H#define _ASM_PGALLOC_H #include <linux/gfp.h>#include <linux/mm.h>#include <linux/threads.h>#include <asm/processor.h>#include <asm/fixmap.h> #include <asm/cache.h> #define __HAVE_ARCH_PMD_ALLOC_ONE#define __HAVE_ARCH_PMD_FREE#define __HAVE_ARCH_PGD_FREE#include <asm-generic/pgalloc.h> /* Allocate the top level pgd (page directory) * * Here (for 64 bit kernels) we implement a Hybrid L2/L3 scheme: we * allocate the first pmd adjacent to the pgd.  This means that we can * subtract a constant offset to get to it.  The pmd and pgd sizes are * arranged so that a single pmd covers 4GB (giving a full 64-bit * process access to 8TB) so our lookups are effectively L2 for the * first 4GB of the kernel (i.e. for all ILP32 processes and all the * kernel for machines with under 4GB of memory) */static inline pgd_t *pgd_alloc(struct mm_struct *mm){	pgd_t *pgd = (pgd_t *)__get_free_pages(GFP_KERNEL,					       PGD_ALLOC_ORDER);	pgd_t *actual_pgd = pgd; 	if (likely(pgd != NULL)) {		memset(pgd, 0, PAGE_SIZE<<PGD_ALLOC_ORDER);#if CONFIG_PGTABLE_LEVELS == 3		actual_pgd += PTRS_PER_PGD;		/* Populate first pmd with allocated memory.  We mark it		 * with PxD_FLAG_ATTACHED as a signal to the system that this		 * pmd entry may not be cleared. */		set_pgd(actual_pgd, __pgd((PxD_FLAG_PRESENT |				        PxD_FLAG_VALID |					PxD_FLAG_ATTACHED)			+ (__u32)(__pa((unsigned long)pgd) >> PxD_VALUE_SHIFT)));		/* The first pmd entry also is marked with PxD_FLAG_ATTACHED as		 * a signal that this pmd may not be freed */		set_pgd(pgd, __pgd(PxD_FLAG_ATTACHED));#endif	}	spin_lock_init(pgd_spinlock(actual_pgd));	return actual_pgd;} static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd){#if CONFIG_PGTABLE_LEVELS == 3	pgd -= PTRS_PER_PGD;#endif	free_pages((unsigned long)pgd, PGD_ALLOC_ORDER);} #if CONFIG_PGTABLE_LEVELS == 3 /* Three Level Page Table Support for pmd's */ static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd){	set_pud(pud, __pud((PxD_FLAG_PRESENT | PxD_FLAG_VALID) +			(__u32)(__pa((unsigned long)pmd) >> PxD_VALUE_SHIFT)));} static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address){	return (pmd_t *)__get_free_pages(GFP_PGTABLE_KERNEL, PMD_ORDER);} static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd){	if (pmd_flag(*pmd) & PxD_FLAG_ATTACHED) {		/*		 * This is the permanent pmd attached to the pgd;		 * cannot free it.		 * Increment the counter to compensate for the decrement		 * done by generic mm code.		 */		mm_inc_nr_pmds(mm);		return;	}	free_pages((unsigned long)pmd, PMD_ORDER);} #endif static inline voidpmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte){#if CONFIG_PGTABLE_LEVELS == 3	/* preserve the gateway marker if this is the beginning of	 * the permanent pmd */	if(pmd_flag(*pmd) & PxD_FLAG_ATTACHED)		set_pmd(pmd, __pmd((PxD_FLAG_PRESENT |				PxD_FLAG_VALID |				PxD_FLAG_ATTACHED)			+ (__u32)(__pa((unsigned long)pte) >> PxD_VALUE_SHIFT)));	else#endif		set_pmd(pmd, __pmd((PxD_FLAG_PRESENT | PxD_FLAG_VALID)			+ (__u32)(__pa((unsigned long)pte) >> PxD_VALUE_SHIFT)));} #define pmd_populate(mm, pmd, pte_page) \	pmd_populate_kernel(mm, pmd, page_address(pte_page))#define pmd_pgtable(pmd) pmd_page(pmd) #endif