Orange Pi5 kernel

/* 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 void
pmd_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