// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
 */
#include <linux/init.h>
#include <linux/export.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/pagemap.h>
#include <linux/memblock.h>
#include <linux/memremap.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/highmem.h>
#include <linux/swap.h>
#include <linux/proc_fs.h>
#include <linux/pfn.h>
#include <linux/hardirq.h>
#include <linux/gfp.h>
#include <linux/hugetlb.h>
#include <linux/mmzone.h>
#include <linux/execmem.h>

#include <asm/asm-offsets.h>
#include <asm/bootinfo.h>
#include <asm/cpu.h>
#include <asm/dma.h>
#include <asm/mmu_context.h>
#include <asm/sections.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/tlb.h>

int __ref page_is_ram(unsigned long pfn)
{
	unsigned long addr = PFN_PHYS(pfn);

	return memblock_is_memory(addr) && !memblock_is_reserved(addr);
}

void __init arch_zone_limits_init(unsigned long *max_zone_pfns)
{
#ifdef CONFIG_ZONE_DMA32
	max_zone_pfns[ZONE_DMA32] = MAX_DMA32_PFN;
#endif
	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
#ifdef CONFIG_HIGHMEM
	max_zone_pfns[ZONE_HIGHMEM] = max_pfn;
#endif
}

void __ref free_initmem(void)
{
	free_initmem_default(POISON_FREE_INITMEM);
}

#ifdef CONFIG_HIGHMEM

void __init fixrange_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
{
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte;
	int i, j, k;
	int ptrs_per_pgd;
	unsigned long vaddr;

	vaddr = start;
	i = pgd_index(vaddr);
	j = pud_index(vaddr);
	k = pmd_index(vaddr);
	pgd = pgd_base + i;
	ptrs_per_pgd = min((1 << (BITS_PER_LONG - PGDIR_SHIFT)), PTRS_PER_PGD);

	for ( ; (i < ptrs_per_pgd) && (vaddr < end); pgd++, i++) {
		pud = (pud_t *)pgd;
		for ( ; (j < PTRS_PER_PUD) && (vaddr < end); pud++, j++) {
			pmd = (pmd_t *)pud;
			for (; (k < PTRS_PER_PMD) && (vaddr < end); pmd++, k++) {
				if (pmd_none(*pmd)) {
					pte = (pte_t *) memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
					if (!pte)
						panic("%s: Failed to allocate %lu bytes align=%lx\n",
						      __func__, PAGE_SIZE, PAGE_SIZE);

					kernel_pte_init(pte);
					set_pmd(pmd, __pmd((unsigned long)pte));
					BUG_ON(pte != pte_offset_kernel(pmd, 0));
				}
				vaddr += PMD_SIZE;
			}
			k = 0;
		}
		j = 0;
	}
}

#endif

#ifdef CONFIG_MEMORY_HOTPLUG
int arch_add_memory(int nid, u64 start, u64 size, struct mhp_params *params)
{
	unsigned long start_pfn = start >> PAGE_SHIFT;
	unsigned long nr_pages = size >> PAGE_SHIFT;
	int ret;

	ret = __add_pages(nid, start_pfn, nr_pages, params);

	if (ret)
		pr_warn("%s: Problem encountered in __add_pages() as ret=%d\n",
				__func__,  ret);

	return ret;
}

void arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap)
{
	unsigned long start_pfn = start >> PAGE_SHIFT;
	unsigned long nr_pages = size >> PAGE_SHIFT;

	__remove_pages(start_pfn, nr_pages, altmap);
}
#endif

#ifdef CONFIG_SPARSEMEM_VMEMMAP
void __meminit vmemmap_set_pmd(pmd_t *pmd, void *p, int node,
			       unsigned long addr, unsigned long next)
{
	pmd_t entry;

	entry = pfn_pmd(virt_to_pfn(p), PAGE_KERNEL);
	pmd_val(entry) |= _PAGE_HUGE | _PAGE_HGLOBAL;
	set_pmd_at(&init_mm, addr, pmd, entry);
}

int __meminit vmemmap_check_pmd(pmd_t *pmd, int node,
				unsigned long addr, unsigned long next)
{
	int huge = pmd_val(pmdp_get(pmd)) & _PAGE_HUGE;

	if (huge)
		vmemmap_verify((pte_t *)pmd, node, addr, next);

	return huge;
}

int __meminit vmemmap_populate(unsigned long start, unsigned long end,
			       int node, struct vmem_altmap *altmap)
{
#if CONFIG_PGTABLE_LEVELS == 2
	return vmemmap_populate_basepages(start, end, node, NULL);
#else
	return vmemmap_populate_hugepages(start, end, node, NULL);
#endif
}

#ifdef CONFIG_MEMORY_HOTPLUG
void vmemmap_free(unsigned long start, unsigned long end, struct vmem_altmap *altmap)
{
}
#endif
#endif

pte_t * __init populate_kernel_pte(unsigned long addr)
{
	pgd_t *pgd = pgd_offset_k(addr);
	p4d_t *p4d = p4d_offset(pgd, addr);
	pud_t *pud;
	pmd_t *pmd;

	if (p4d_none(p4dp_get(p4d))) {
		pud = memblock_alloc_or_panic(PAGE_SIZE, PAGE_SIZE);
		p4d_populate(&init_mm, p4d, pud);
#ifndef __PAGETABLE_PUD_FOLDED
		pud_init(pud);
#endif
	}

	pud = pud_offset(p4d, addr);
	if (pud_none(pudp_get(pud))) {
		pmd = memblock_alloc_or_panic(PAGE_SIZE, PAGE_SIZE);
		pud_populate(&init_mm, pud, pmd);
#ifndef __PAGETABLE_PMD_FOLDED
		pmd_init(pmd);
#endif
	}

	pmd = pmd_offset(pud, addr);
	if (!pmd_present(pmdp_get(pmd))) {
		pte_t *pte;

		pte = memblock_alloc_or_panic(PAGE_SIZE, PAGE_SIZE);
		pmd_populate_kernel(&init_mm, pmd, pte);
		kernel_pte_init(pte);
	}

	return pte_offset_kernel(pmd, addr);
}

void __init __set_fixmap(enum fixed_addresses idx,
			       phys_addr_t phys, pgprot_t flags)
{
	unsigned long addr = __fix_to_virt(idx);
	pte_t *ptep;

	BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);

	ptep = populate_kernel_pte(addr);
	if (!pte_none(ptep_get(ptep))) {
		pte_ERROR(*ptep);
		return;
	}

	if (pgprot_val(flags))
		set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, flags));
	else {
		pte_clear(&init_mm, addr, ptep);
		flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
	}
}

/*
 * Align swapper_pg_dir in to 64K, allows its address to be loaded
 * with a single LUI instruction in the TLB handlers.  If we used
 * __aligned(64K), its size would get rounded up to the alignment
 * size, and waste space.  So we place it in its own section and align
 * it in the linker script.
 */
pgd_t swapper_pg_dir[_PTRS_PER_PGD] __section(".bss..swapper_pg_dir");

pgd_t invalid_pg_dir[_PTRS_PER_PGD] __page_aligned_bss;
#ifndef __PAGETABLE_PUD_FOLDED
pud_t invalid_pud_table[PTRS_PER_PUD] __page_aligned_bss;
EXPORT_SYMBOL(invalid_pud_table);
#endif
#ifndef __PAGETABLE_PMD_FOLDED
pmd_t invalid_pmd_table[PTRS_PER_PMD] __page_aligned_bss;
EXPORT_SYMBOL(invalid_pmd_table);
#endif
pte_t invalid_pte_table[PTRS_PER_PTE] __page_aligned_bss;
EXPORT_SYMBOL(invalid_pte_table);

#if defined(CONFIG_EXECMEM) && defined(MODULES_VADDR)
static struct execmem_info execmem_info __ro_after_init;

struct execmem_info __init *execmem_arch_setup(void)
{
	execmem_info = (struct execmem_info){
		.ranges = {
			[EXECMEM_DEFAULT] = {
				.start	= MODULES_VADDR,
				.end	= MODULES_END,
				.pgprot	= PAGE_KERNEL,
				.alignment = 1,
			},
		},
	};

	return &execmem_info;
}
#endif /* CONFIG_EXECMEM && MODULES_VADDR */