// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright IBM Corp. 2011
 * Author(s): Jan Glauber <jang@linux.vnet.ibm.com>
 */
#include <linux/cpufeature.h>
#include <linux/hugetlb.h>
#include <linux/proc_fs.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <asm/cacheflush.h>
#include <asm/facility.h>
#include <asm/pgalloc.h>
#include <asm/kfence.h>
#include <asm/page.h>
#include <asm/asm.h>
#include <asm/set_memory.h>

void __storage_key_init_range(unsigned long start, unsigned long end)
{
        unsigned long boundary, size;

        while (start < end) {
                if (cpu_has_edat1()) {
                        /* set storage keys for a 1MB frame */
                        size = 1UL << 20;
                        boundary = (start + size) & ~(size - 1);
                        if (boundary <= end) {
                                do {
                                        start = sske_frame(start, PAGE_DEFAULT_KEY);
                                } while (start < boundary);
                                continue;
                        }
                }
                page_set_storage_key(start, PAGE_DEFAULT_KEY, 1);
                start += PAGE_SIZE;
        }
}

#ifdef CONFIG_PROC_FS
atomic_long_t __bootdata_preserved(direct_pages_count[PG_DIRECT_MAP_MAX]);

void arch_report_meminfo(struct seq_file *m)
{
        seq_printf(m, "DirectMap4k:    %8lu kB\n",
                   atomic_long_read(&direct_pages_count[PG_DIRECT_MAP_4K]) << 2);
        seq_printf(m, "DirectMap1M:    %8lu kB\n",
                   atomic_long_read(&direct_pages_count[PG_DIRECT_MAP_1M]) << 10);
        seq_printf(m, "DirectMap2G:    %8lu kB\n",
                   atomic_long_read(&direct_pages_count[PG_DIRECT_MAP_2G]) << 21);
}
#endif /* CONFIG_PROC_FS */

static void pgt_set(unsigned long *old, unsigned long new, unsigned long addr,
                    unsigned long dtt)
{
        unsigned long *table, mask;

        mask = 0;
        if (cpu_has_edat2()) {
                switch (dtt) {
                case CRDTE_DTT_REGION3:
                        mask = ~(PTRS_PER_PUD * sizeof(pud_t) - 1);
                        break;
                case CRDTE_DTT_SEGMENT:
                        mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
                        break;
                case CRDTE_DTT_PAGE:
                        mask = ~(PTRS_PER_PTE * sizeof(pte_t) - 1);
                        break;
                }
                table = (unsigned long *)((unsigned long)old & mask);
                crdte(*old, new, table, dtt, addr, get_lowcore()->kernel_asce.val);
        } else {
                cspg(old, *old, new);
        }
}

static int walk_pte_level(pmd_t *pmdp, unsigned long addr, unsigned long end,
                          unsigned long flags)
{
        pte_t *ptep, new;

        if (flags == SET_MEMORY_4K)
                return 0;
        ptep = pte_offset_kernel(pmdp, addr);
        do {
                new = *ptep;
                if (pte_none(new))
                        return -EINVAL;
                if (flags & SET_MEMORY_RO)
                        new = pte_wrprotect(new);
                else if (flags & SET_MEMORY_RW)
                        new = pte_mkwrite_novma(pte_mkdirty(new));
                if (flags & SET_MEMORY_NX)
                        new = set_pte_bit(new, __pgprot(_PAGE_NOEXEC));
                else if (flags & SET_MEMORY_X)
                        new = clear_pte_bit(new, __pgprot(_PAGE_NOEXEC));
                if (flags & SET_MEMORY_INV) {
                        new = set_pte_bit(new, __pgprot(_PAGE_INVALID));
                } else if (flags & SET_MEMORY_DEF) {
                        new = __pte(pte_val(new) & PAGE_MASK);
                        new = set_pte_bit(new, PAGE_KERNEL);
                }
                pgt_set((unsigned long *)ptep, pte_val(new), addr, CRDTE_DTT_PAGE);
                ptep++;
                addr += PAGE_SIZE;
                cond_resched();
        } while (addr < end);
        return 0;
}

static int split_pmd_page(pmd_t *pmdp, unsigned long addr)
{
        unsigned long pte_addr, prot;
        pte_t *pt_dir, *ptep;
        pmd_t new;
        int i, ro, nx;

        pt_dir = vmem_pte_alloc();
        if (!pt_dir)
                return -ENOMEM;
        pte_addr = pmd_pfn(*pmdp) << PAGE_SHIFT;
        ro = !!(pmd_val(*pmdp) & _SEGMENT_ENTRY_PROTECT);
        nx = !!(pmd_val(*pmdp) & _SEGMENT_ENTRY_NOEXEC);
        prot = pgprot_val(ro ? PAGE_KERNEL_RO : PAGE_KERNEL);
        if (!nx)
                prot &= ~_PAGE_NOEXEC;
        ptep = pt_dir;
        for (i = 0; i < PTRS_PER_PTE; i++) {
                set_pte(ptep, __pte(pte_addr | prot));
                pte_addr += PAGE_SIZE;
                ptep++;
        }
        new = __pmd(__pa(pt_dir) | _SEGMENT_ENTRY);
        pgt_set((unsigned long *)pmdp, pmd_val(new), addr, CRDTE_DTT_SEGMENT);
        update_page_count(PG_DIRECT_MAP_4K, PTRS_PER_PTE);
        update_page_count(PG_DIRECT_MAP_1M, -1);
        return 0;
}

static void modify_pmd_page(pmd_t *pmdp, unsigned long addr,
                            unsigned long flags)
{
        pmd_t new = *pmdp;

        if (flags & SET_MEMORY_RO)
                new = pmd_wrprotect(new);
        else if (flags & SET_MEMORY_RW)
                new = pmd_mkwrite_novma(pmd_mkdirty(new));
        if (flags & SET_MEMORY_NX)
                new = set_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_NOEXEC));
        else if (flags & SET_MEMORY_X)
                new = clear_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_NOEXEC));
        if (flags & SET_MEMORY_INV) {
                new = set_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_INVALID));
        } else if (flags & SET_MEMORY_DEF) {
                new = __pmd(pmd_val(new) & PMD_MASK);
                new = set_pmd_bit(new, SEGMENT_KERNEL);
        }
        pgt_set((unsigned long *)pmdp, pmd_val(new), addr, CRDTE_DTT_SEGMENT);
}

static int walk_pmd_level(pud_t *pudp, unsigned long addr, unsigned long end,
                          unsigned long flags)
{
        unsigned long next;
        int need_split;
        pmd_t *pmdp;
        int rc = 0;

        pmdp = pmd_offset(pudp, addr);
        do {
                if (pmd_none(*pmdp))
                        return -EINVAL;
                next = pmd_addr_end(addr, end);
                if (pmd_leaf(*pmdp)) {
                        need_split  = !!(flags & SET_MEMORY_4K);
                        need_split |= !!(addr & ~PMD_MASK);
                        need_split |= !!(addr + PMD_SIZE > next);
                        if (need_split) {
                                rc = split_pmd_page(pmdp, addr);
                                if (rc)
                                        return rc;
                                continue;
                        }
                        modify_pmd_page(pmdp, addr, flags);
                } else {
                        rc = walk_pte_level(pmdp, addr, next, flags);
                        if (rc)
                                return rc;
                }
                pmdp++;
                addr = next;
                cond_resched();
        } while (addr < end);
        return rc;
}

int split_pud_page(pud_t *pudp, unsigned long addr)
{
        unsigned long pmd_addr, prot;
        pmd_t *pm_dir, *pmdp;
        pud_t new;
        int i, ro, nx;

        pm_dir = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
        if (!pm_dir)
                return -ENOMEM;
        pmd_addr = pud_pfn(*pudp) << PAGE_SHIFT;
        ro = !!(pud_val(*pudp) & _REGION_ENTRY_PROTECT);
        nx = !!(pud_val(*pudp) & _REGION_ENTRY_NOEXEC);
        prot = pgprot_val(ro ? SEGMENT_KERNEL_RO : SEGMENT_KERNEL);
        if (!nx)
                prot &= ~_SEGMENT_ENTRY_NOEXEC;
        pmdp = pm_dir;
        for (i = 0; i < PTRS_PER_PMD; i++) {
                set_pmd(pmdp, __pmd(pmd_addr | prot));
                pmd_addr += PMD_SIZE;
                pmdp++;
        }
        new = __pud(__pa(pm_dir) | _REGION3_ENTRY);
        pgt_set((unsigned long *)pudp, pud_val(new), addr, CRDTE_DTT_REGION3);
        update_page_count(PG_DIRECT_MAP_1M, PTRS_PER_PMD);
        update_page_count(PG_DIRECT_MAP_2G, -1);
        return 0;
}

static void modify_pud_page(pud_t *pudp, unsigned long addr,
                            unsigned long flags)
{
        pud_t new = *pudp;

        if (flags & SET_MEMORY_RO)
                new = pud_wrprotect(new);
        else if (flags & SET_MEMORY_RW)
                new = pud_mkwrite(pud_mkdirty(new));
        if (flags & SET_MEMORY_NX)
                new = set_pud_bit(new, __pgprot(_REGION_ENTRY_NOEXEC));
        else if (flags & SET_MEMORY_X)
                new = clear_pud_bit(new, __pgprot(_REGION_ENTRY_NOEXEC));
        if (flags & SET_MEMORY_INV) {
                new = set_pud_bit(new, __pgprot(_REGION_ENTRY_INVALID));
        } else if (flags & SET_MEMORY_DEF) {
                new = __pud(pud_val(new) & PUD_MASK);
                new = set_pud_bit(new, REGION3_KERNEL);
        }
        pgt_set((unsigned long *)pudp, pud_val(new), addr, CRDTE_DTT_REGION3);
}

static int walk_pud_level(p4d_t *p4d, unsigned long addr, unsigned long end,
                          unsigned long flags)
{
        unsigned long next;
        int need_split;
        pud_t *pudp;
        int rc = 0;

        pudp = pud_offset(p4d, addr);
        do {
                if (pud_none(*pudp))
                        return -EINVAL;
                next = pud_addr_end(addr, end);
                if (pud_leaf(*pudp)) {
                        need_split  = !!(flags & SET_MEMORY_4K);
                        need_split |= !!(addr & ~PUD_MASK);
                        need_split |= !!(addr + PUD_SIZE > next);
                        if (need_split) {
                                rc = split_pud_page(pudp, addr);
                                if (rc)
                                        break;
                                continue;
                        }
                        modify_pud_page(pudp, addr, flags);
                } else {
                        rc = walk_pmd_level(pudp, addr, next, flags);
                }
                pudp++;
                addr = next;
                cond_resched();
        } while (addr < end && !rc);
        return rc;
}

static int walk_p4d_level(pgd_t *pgd, unsigned long addr, unsigned long end,
                          unsigned long flags)
{
        unsigned long next;
        p4d_t *p4dp;
        int rc = 0;

        p4dp = p4d_offset(pgd, addr);
        do {
                if (p4d_none(*p4dp))
                        return -EINVAL;
                next = p4d_addr_end(addr, end);
                rc = walk_pud_level(p4dp, addr, next, flags);
                p4dp++;
                addr = next;
                cond_resched();
        } while (addr < end && !rc);
        return rc;
}

DEFINE_MUTEX(cpa_mutex);

static int change_page_attr(unsigned long addr, unsigned long end,
                            unsigned long flags)
{
        unsigned long next;
        int rc = -EINVAL;
        pgd_t *pgdp;

        pgdp = pgd_offset_k(addr);
        do {
                if (pgd_none(*pgdp))
                        break;
                next = pgd_addr_end(addr, end);
                rc = walk_p4d_level(pgdp, addr, next, flags);
                if (rc)
                        break;
                cond_resched();
        } while (pgdp++, addr = next, addr < end && !rc);
        return rc;
}

static int change_page_attr_alias(unsigned long addr, unsigned long end,
                                  unsigned long flags)
{
        unsigned long alias, offset, va_start, va_end;
        struct vm_struct *area;
        int rc = 0;

        /*
         * Changes to read-only permissions on kernel VA mappings are also
         * applied to the kernel direct mapping. Execute permissions are
         * intentionally not transferred to keep all allocated pages within
         * the direct mapping non-executable.
         */
        flags &= SET_MEMORY_RO | SET_MEMORY_RW;
        if (!flags)
                return 0;
        area = NULL;
        while (addr < end) {
                if (!area)
                        area = find_vm_area((void *)addr);
                if (!area || !(area->flags & VM_ALLOC))
                        return 0;
                va_start = (unsigned long)area->addr;
                va_end = va_start + area->nr_pages * PAGE_SIZE;
                offset = (addr - va_start) >> PAGE_SHIFT;
                alias = (unsigned long)page_address(area->pages[offset]);
                rc = change_page_attr(alias, alias + PAGE_SIZE, flags);
                if (rc)
                        break;
                addr += PAGE_SIZE;
                if (addr >= va_end)
                        area = NULL;
        }
        return rc;
}

int __set_memory(unsigned long addr, unsigned long numpages, unsigned long flags)
{
        unsigned long end;
        int rc;

        if (!cpu_has_nx())
                flags &= ~(SET_MEMORY_NX | SET_MEMORY_X);
        if (!flags)
                return 0;
        if (!numpages)
                return 0;
        addr &= PAGE_MASK;
        end = addr + numpages * PAGE_SIZE;
        mutex_lock(&cpa_mutex);
        rc = change_page_attr(addr, end, flags);
        if (rc)
                goto out;
        rc = change_page_attr_alias(addr, end, flags);
out:
        mutex_unlock(&cpa_mutex);
        return rc;
}

int set_direct_map_invalid_noflush(struct page *page)
{
        return __set_memory((unsigned long)page_to_virt(page), 1, SET_MEMORY_INV);
}

int set_direct_map_default_noflush(struct page *page)
{
        return __set_memory((unsigned long)page_to_virt(page), 1, SET_MEMORY_DEF);
}

int set_direct_map_valid_noflush(struct page *page, unsigned nr, bool valid)
{
        unsigned long flags;

        if (valid)
                flags = SET_MEMORY_DEF;
        else
                flags = SET_MEMORY_INV;

        return __set_memory((unsigned long)page_to_virt(page), nr, flags);
}

bool kernel_page_present(struct page *page)
{
        unsigned long addr;
        unsigned int cc;

        addr = (unsigned long)page_address(page);
        asm volatile(
                "       lra     %[addr],0(%[addr])\n"
                CC_IPM(cc)
                : CC_OUT(cc, cc), [addr] "+a" (addr)
                :
                : CC_CLOBBER);
        return CC_TRANSFORM(cc) == 0;
}

#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE)

static void ipte_range(pte_t *pte, unsigned long address, int nr)
{
        int i;

        if (test_facility(13)) {
                __ptep_ipte_range(address, nr - 1, pte, IPTE_GLOBAL);
                return;
        }
        for (i = 0; i < nr; i++) {
                __ptep_ipte(address, pte, 0, 0, IPTE_GLOBAL);
                address += PAGE_SIZE;
                pte++;
        }
}

void __kernel_map_pages(struct page *page, int numpages, int enable)
{
        unsigned long address;
        pte_t *ptep, pte;
        int nr, i, j;

        for (i = 0; i < numpages;) {
                address = (unsigned long)page_to_virt(page + i);
                ptep = virt_to_kpte(address);
                nr = (unsigned long)ptep >> ilog2(sizeof(long));
                nr = PTRS_PER_PTE - (nr & (PTRS_PER_PTE - 1));
                nr = min(numpages - i, nr);
                if (enable) {
                        for (j = 0; j < nr; j++) {
                                pte = clear_pte_bit(*ptep, __pgprot(_PAGE_INVALID));
                                set_pte(ptep, pte);
                                address += PAGE_SIZE;
                                ptep++;
                        }
                } else {
                        ipte_range(ptep, address, nr);
                }
                i += nr;
        }
}

#endif /* CONFIG_DEBUG_PAGEALLOC */