// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  PowerPC version
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *
 *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
 *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
 *    Copyright (C) 1996 Paul Mackerras
 *  PPC44x/36-bit changes by Matt Porter (mporter@mvista.com)
 *
 *  Derived from "arch/i386/mm/init.c"
 *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
 */

#include <linux/export.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/gfp.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/stddef.h>
#include <linux/init.h>
#include <linux/memblock.h>
#include <linux/highmem.h>
#include <linux/initrd.h>
#include <linux/pagemap.h>
#include <linux/suspend.h>
#include <linux/hugetlb.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/memremap.h>

#include <asm/pgalloc.h>
#include <asm/prom.h>
#include <asm/io.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/mmu.h>
#include <asm/smp.h>
#include <asm/machdep.h>
#include <asm/btext.h>
#include <asm/tlb.h>
#include <asm/sections.h>
#include <asm/sparsemem.h>
#include <asm/vdso.h>
#include <asm/fixmap.h>
#include <asm/swiotlb.h>
#include <asm/rtas.h>

#include <mm/mmu_decl.h>

#ifndef CPU_FTR_COHERENT_ICACHE
#define CPU_FTR_COHERENT_ICACHE 0       /* XXX for now */
#define CPU_FTR_NOEXECUTE       0
#endif

unsigned long long memory_limit;
bool init_mem_is_free;

#ifdef CONFIG_HIGHMEM
pte_t *kmap_pte;
EXPORT_SYMBOL(kmap_pte);
pgprot_t kmap_prot;
EXPORT_SYMBOL(kmap_prot);

static inline pte_t *virt_to_kpte(unsigned long vaddr)
{
        return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
                        vaddr), vaddr), vaddr);
}
#endif

pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
                              unsigned long size, pgprot_t vma_prot)
{
        if (ppc_md.phys_mem_access_prot)
                return ppc_md.phys_mem_access_prot(file, pfn, size, vma_prot);

        if (!page_is_ram(pfn))
                vma_prot = pgprot_noncached(vma_prot);

        return vma_prot;
}
EXPORT_SYMBOL(phys_mem_access_prot);

#ifdef CONFIG_MEMORY_HOTPLUG

#ifdef CONFIG_NUMA
int memory_add_physaddr_to_nid(u64 start)
{
        return hot_add_scn_to_nid(start);
}
#endif

int __weak create_section_mapping(unsigned long start, unsigned long end, int nid)
{
        return -ENODEV;
}

int __weak remove_section_mapping(unsigned long start, unsigned long end)
{
        return -ENODEV;
}

int __ref arch_add_memory(int nid, u64 start, u64 size,
                        struct mhp_restrictions *restrictions)
{
        unsigned long start_pfn = start >> PAGE_SHIFT;
        unsigned long nr_pages = size >> PAGE_SHIFT;
        int rc;

        resize_hpt_for_hotplug(memblock_phys_mem_size());

        start = (unsigned long)__va(start);
        rc = create_section_mapping(start, start + size, nid);
        if (rc) {
                pr_warn("Unable to create mapping for hot added memory 0x%llx..0x%llx: %d\n",
                        start, start + size, rc);
                return -EFAULT;
        }
        flush_dcache_range(start, start + size);

        return __add_pages(nid, start_pfn, nr_pages, restrictions);
}

void __ref arch_remove_memory(int nid, u64 start, u64 size,
                             struct vmem_altmap *altmap)
{
        unsigned long start_pfn = start >> PAGE_SHIFT;
        unsigned long nr_pages = size >> PAGE_SHIFT;
        struct page *page = pfn_to_page(start_pfn) + vmem_altmap_offset(altmap);
        int ret;

        __remove_pages(page_zone(page), start_pfn, nr_pages, altmap);

        /* Remove htab bolted mappings for this section of memory */
        start = (unsigned long)__va(start);
        flush_dcache_range(start, start + size);
        ret = remove_section_mapping(start, start + size);
        WARN_ON_ONCE(ret);

        /* Ensure all vmalloc mappings are flushed in case they also
         * hit that section of memory
         */
        vm_unmap_aliases();

        if (resize_hpt_for_hotplug(memblock_phys_mem_size()) == -ENOSPC)
                pr_warn("Hash collision while resizing HPT\n");
}
#endif

#ifndef CONFIG_NEED_MULTIPLE_NODES
void __init mem_topology_setup(void)
{
        max_low_pfn = max_pfn = memblock_end_of_DRAM() >> PAGE_SHIFT;
        min_low_pfn = MEMORY_START >> PAGE_SHIFT;
#ifdef CONFIG_HIGHMEM
        max_low_pfn = lowmem_end_addr >> PAGE_SHIFT;
#endif

        /* Place all memblock_regions in the same node and merge contiguous
         * memblock_regions
         */
        memblock_set_node(0, PHYS_ADDR_MAX, &memblock.memory, 0);
}

void __init initmem_init(void)
{
        /* XXX need to clip this if using highmem? */
        sparse_memory_present_with_active_regions(0);
        sparse_init();
}

/* mark pages that don't exist as nosave */
static int __init mark_nonram_nosave(void)
{
        struct memblock_region *reg, *prev = NULL;

        for_each_memblock(memory, reg) {
                if (prev &&
                    memblock_region_memory_end_pfn(prev) < memblock_region_memory_base_pfn(reg))
                        register_nosave_region(memblock_region_memory_end_pfn(prev),
                                               memblock_region_memory_base_pfn(reg));
                prev = reg;
        }
        return 0;
}
#else /* CONFIG_NEED_MULTIPLE_NODES */
static int __init mark_nonram_nosave(void)
{
        return 0;
}
#endif

/*
 * Zones usage:
 *
 * We setup ZONE_DMA to be 31-bits on all platforms and ZONE_NORMAL to be
 * everything else. GFP_DMA32 page allocations automatically fall back to
 * ZONE_DMA.
 *
 * By using 31-bit unconditionally, we can exploit ARCH_ZONE_DMA_BITS to
 * inform the generic DMA mapping code.  32-bit only devices (if not handled
 * by an IOMMU anyway) will take a first dip into ZONE_NORMAL and get
 * otherwise served by ZONE_DMA.
 */
static unsigned long max_zone_pfns[MAX_NR_ZONES];

/*
 * paging_init() sets up the page tables - in fact we've already done this.
 */
void __init paging_init(void)
{
        unsigned long long total_ram = memblock_phys_mem_size();
        phys_addr_t top_of_ram = memblock_end_of_DRAM();

#ifdef CONFIG_PPC32
        unsigned long v = __fix_to_virt(__end_of_fixed_addresses - 1);
        unsigned long end = __fix_to_virt(FIX_HOLE);

        for (; v < end; v += PAGE_SIZE)
                map_kernel_page(v, 0, __pgprot(0)); /* XXX gross */
#endif

#ifdef CONFIG_HIGHMEM
        map_kernel_page(PKMAP_BASE, 0, __pgprot(0));    /* XXX gross */
        pkmap_page_table = virt_to_kpte(PKMAP_BASE);

        kmap_pte = virt_to_kpte(__fix_to_virt(FIX_KMAP_BEGIN));
        kmap_prot = PAGE_KERNEL;
#endif /* CONFIG_HIGHMEM */

        printk(KERN_DEBUG "Top of RAM: 0x%llx, Total RAM: 0x%llx\n",
               (unsigned long long)top_of_ram, total_ram);
        printk(KERN_DEBUG "Memory hole size: %ldMB\n",
               (long int)((top_of_ram - total_ram) >> 20));

#ifdef CONFIG_ZONE_DMA
        max_zone_pfns[ZONE_DMA] = min(max_low_pfn,
                                      1UL << (ARCH_ZONE_DMA_BITS - PAGE_SHIFT));
#endif
        max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
#ifdef CONFIG_HIGHMEM
        max_zone_pfns[ZONE_HIGHMEM] = max_pfn;
#endif

        free_area_init_nodes(max_zone_pfns);

        mark_nonram_nosave();
}

void __init mem_init(void)
{
        /*
         * book3s is limited to 16 page sizes due to encoding this in
         * a 4-bit field for slices.
         */
        BUILD_BUG_ON(MMU_PAGE_COUNT > 16);

#ifdef CONFIG_SWIOTLB
        swiotlb_init(0);
#endif

        high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
        set_max_mapnr(max_pfn);
        memblock_free_all();

#ifdef CONFIG_HIGHMEM
        {
                unsigned long pfn, highmem_mapnr;

                highmem_mapnr = lowmem_end_addr >> PAGE_SHIFT;
                for (pfn = highmem_mapnr; pfn < max_mapnr; ++pfn) {
                        phys_addr_t paddr = (phys_addr_t)pfn << PAGE_SHIFT;
                        struct page *page = pfn_to_page(pfn);
                        if (!memblock_is_reserved(paddr))
                                free_highmem_page(page);
                }
        }
#endif /* CONFIG_HIGHMEM */

#if defined(CONFIG_PPC_FSL_BOOK3E) && !defined(CONFIG_SMP)
        /*
         * If smp is enabled, next_tlbcam_idx is initialized in the cpu up
         * functions.... do it here for the non-smp case.
         */
        per_cpu(next_tlbcam_idx, smp_processor_id()) =
                (mfspr(SPRN_TLB1CFG) & TLBnCFG_N_ENTRY) - 1;
#endif

        mem_init_print_info(NULL);
#ifdef CONFIG_PPC32
        pr_info("Kernel virtual memory layout:\n");
#ifdef CONFIG_KASAN
        pr_info("  * 0x%08lx..0x%08lx  : kasan shadow mem\n",
                KASAN_SHADOW_START, KASAN_SHADOW_END);
#endif
        pr_info("  * 0x%08lx..0x%08lx  : fixmap\n", FIXADDR_START, FIXADDR_TOP);
#ifdef CONFIG_HIGHMEM
        pr_info("  * 0x%08lx..0x%08lx  : highmem PTEs\n",
                PKMAP_BASE, PKMAP_ADDR(LAST_PKMAP));
#endif /* CONFIG_HIGHMEM */
#ifdef CONFIG_NOT_COHERENT_CACHE
        pr_info("  * 0x%08lx..0x%08lx  : consistent mem\n",
                IOREMAP_TOP, IOREMAP_TOP + CONFIG_CONSISTENT_SIZE);
#endif /* CONFIG_NOT_COHERENT_CACHE */
        pr_info("  * 0x%08lx..0x%08lx  : early ioremap\n",
                ioremap_bot, IOREMAP_TOP);
        pr_info("  * 0x%08lx..0x%08lx  : vmalloc & ioremap\n",
                VMALLOC_START, VMALLOC_END);
#endif /* CONFIG_PPC32 */
}

void free_initmem(void)
{
        ppc_md.progress = ppc_printk_progress;
        mark_initmem_nx();
        init_mem_is_free = true;
        free_initmem_default(POISON_FREE_INITMEM);
}

/*
 * This is called when a page has been modified by the kernel.
 * It just marks the page as not i-cache clean.  We do the i-cache
 * flush later when the page is given to a user process, if necessary.
 */
void flush_dcache_page(struct page *page)
{
        if (cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
                return;
        /* avoid an atomic op if possible */
        if (test_bit(PG_arch_1, &page->flags))
                clear_bit(PG_arch_1, &page->flags);
}
EXPORT_SYMBOL(flush_dcache_page);

void flush_dcache_icache_page(struct page *page)
{
#ifdef CONFIG_HUGETLB_PAGE
        if (PageCompound(page)) {
                flush_dcache_icache_hugepage(page);
                return;
        }
#endif
#if defined(CONFIG_PPC_8xx) || defined(CONFIG_PPC64)
        /* On 8xx there is no need to kmap since highmem is not supported */
        __flush_dcache_icache(page_address(page));
#else
        if (IS_ENABLED(CONFIG_BOOKE) || sizeof(phys_addr_t) > sizeof(void *)) {
                void *start = kmap_atomic(page);
                __flush_dcache_icache(start);
                kunmap_atomic(start);
        } else {
                __flush_dcache_icache_phys(page_to_pfn(page) << PAGE_SHIFT);
        }
#endif
}
EXPORT_SYMBOL(flush_dcache_icache_page);

void clear_user_page(void *page, unsigned long vaddr, struct page *pg)
{
        clear_page(page);

        /*
         * We shouldn't have to do this, but some versions of glibc
         * require it (ld.so assumes zero filled pages are icache clean)
         * - Anton
         */
        flush_dcache_page(pg);
}
EXPORT_SYMBOL(clear_user_page);

void copy_user_page(void *vto, void *vfrom, unsigned long vaddr,
                    struct page *pg)
{
        copy_page(vto, vfrom);

        /*
         * We should be able to use the following optimisation, however
         * there are two problems.
         * Firstly a bug in some versions of binutils meant PLT sections
         * were not marked executable.
         * Secondly the first word in the GOT section is blrl, used
         * to establish the GOT address. Until recently the GOT was
         * not marked executable.
         * - Anton
         */
#if 0
        if (!vma->vm_file && ((vma->vm_flags & VM_EXEC) == 0))
                return;
#endif

        flush_dcache_page(pg);
}

void flush_icache_user_range(struct vm_area_struct *vma, struct page *page,
                             unsigned long addr, int len)
{
        unsigned long maddr;

        maddr = (unsigned long) kmap(page) + (addr & ~PAGE_MASK);
        flush_icache_range(maddr, maddr + len);
        kunmap(page);
}
EXPORT_SYMBOL(flush_icache_user_range);

/*
 * This is called at the end of handling a user page fault, when the
 * fault has been handled by updating a PTE in the linux page tables.
 * We use it to preload an HPTE into the hash table corresponding to
 * the updated linux PTE.
 * 
 * This must always be called with the pte lock held.
 */
void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
                      pte_t *ptep)
{
#ifdef CONFIG_PPC_BOOK3S
        /*
         * We don't need to worry about _PAGE_PRESENT here because we are
         * called with either mm->page_table_lock held or ptl lock held
         */
        unsigned long trap;
        bool is_exec;

        if (radix_enabled()) {
                prefetch((void *)address);
                return;
        }

        /* We only want HPTEs for linux PTEs that have _PAGE_ACCESSED set */
        if (!pte_young(*ptep) || address >= TASK_SIZE)
                return;

        /* We try to figure out if we are coming from an instruction
         * access fault and pass that down to __hash_page so we avoid
         * double-faulting on execution of fresh text. We have to test
         * for regs NULL since init will get here first thing at boot
         *
         * We also avoid filling the hash if not coming from a fault
         */

        trap = current->thread.regs ? TRAP(current->thread.regs) : 0UL;
        switch (trap) {
        case 0x300:
                is_exec = false;
                break;
        case 0x400:
                is_exec = true;
                break;
        default:
                return;
        }

        hash_preload(vma->vm_mm, address, is_exec, trap);
#endif /* CONFIG_PPC_BOOK3S */
#if (defined(CONFIG_PPC_BOOK3E_64) || defined(CONFIG_PPC_FSL_BOOK3E)) \
        && defined(CONFIG_HUGETLB_PAGE)
        if (is_vm_hugetlb_page(vma))
                book3e_hugetlb_preload(vma, address, *ptep);
#endif
}

/*
 * System memory should not be in /proc/iomem but various tools expect it
 * (eg kdump).
 */
static int __init add_system_ram_resources(void)
{
        struct memblock_region *reg;

        for_each_memblock(memory, reg) {
                struct resource *res;
                unsigned long base = reg->base;
                unsigned long size = reg->size;

                res = kzalloc(sizeof(struct resource), GFP_KERNEL);
                WARN_ON(!res);

                if (res) {
                        res->name = "System RAM";
                        res->start = base;
                        res->end = base + size - 1;
                        res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
                        WARN_ON(request_resource(&iomem_resource, res) < 0);
                }
        }

        return 0;
}
subsys_initcall(add_system_ram_resources);

#ifdef CONFIG_STRICT_DEVMEM
/*
 * devmem_is_allowed(): check to see if /dev/mem access to a certain address
 * is valid. The argument is a physical page number.
 *
 * Access has to be given to non-kernel-ram areas as well, these contain the
 * PCI mmio resources as well as potential bios/acpi data regions.
 */
int devmem_is_allowed(unsigned long pfn)
{
        if (page_is_rtas_user_buf(pfn))
                return 1;
        if (iomem_is_exclusive(PFN_PHYS(pfn)))
                return 0;
        if (!page_is_ram(pfn))
                return 1;
        return 0;
}
#endif /* CONFIG_STRICT_DEVMEM */

/*
 * This is defined in kernel/resource.c but only powerpc needs to export it, for
 * the EHEA driver. Drop this when drivers/net/ethernet/ibm/ehea is removed.
 */
EXPORT_SYMBOL_GPL(walk_system_ram_range);