powerpc/mm/pgtable_32.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * This file contains the routines setting up the linux page tables.
0004  *  -- paulus
0005  *
0006  *  Derived from arch/ppc/mm/init.c:
0007  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
0008  *
0009  *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
0010  *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
0011  *    Copyright (C) 1996 Paul Mackerras
0012  *
0013  *  Derived from "arch/i386/mm/init.c"
0014  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
0015  */
0016
0017 #include <linux/kernel.h>
0018 #include <linux/module.h>
0019 #include <linux/types.h>
0020 #include <linux/mm.h>
0021 #include <linux/vmalloc.h>
0022 #include <linux/init.h>
0023 #include <linux/highmem.h>
0024 #include <linux/memblock.h>
0025 #include <linux/slab.h>
0026 #include <linux/set_memory.h>
0027
0028 #include <asm/pgalloc.h>
0029 #include <asm/fixmap.h>
0030 #include <asm/setup.h>
0031 #include <asm/sections.h>
0032 #include <asm/early_ioremap.h>
0033
0034 #include <mm/mmu_decl.h>
0035
0036 static u8 early_fixmap_pagetable[FIXMAP_PTE_SIZE] __page_aligned_data;
0037
0038 notrace void __init early_ioremap_init(void)
0039 {
0040     unsigned long addr = ALIGN_DOWN(FIXADDR_START, PGDIR_SIZE);
0041     pte_t *ptep = (pte_t *)early_fixmap_pagetable;
0042     pmd_t *pmdp = pmd_off_k(addr);
0043
0044     for (; (s32)(FIXADDR_TOP - addr) > 0;
0045          addr += PGDIR_SIZE, ptep += PTRS_PER_PTE, pmdp++)
0046         pmd_populate_kernel(&init_mm, pmdp, ptep);
0047
0048     early_ioremap_setup();
0049 }
0050
0051 static void __init *early_alloc_pgtable(unsigned long size)
0052 {
0053     void *ptr = memblock_alloc(size, size);
0054
0055     if (!ptr)
0056         panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
0057               __func__, size, size);
0058
0059     return ptr;
0060 }
0061
0062 pte_t __init *early_pte_alloc_kernel(pmd_t *pmdp, unsigned long va)
0063 {
0064     if (pmd_none(*pmdp)) {
0065         pte_t *ptep = early_alloc_pgtable(PTE_FRAG_SIZE);
0066
0067         pmd_populate_kernel(&init_mm, pmdp, ptep);
0068     }
0069     return pte_offset_kernel(pmdp, va);
0070 }
0071
0072
0073 int __ref map_kernel_page(unsigned long va, phys_addr_t pa, pgprot_t prot)
0074 {
0075     pmd_t *pd;
0076     pte_t *pg;
0077     int err = -ENOMEM;
0078
0079     /* Use upper 10 bits of VA to index the first level map */
0080     pd = pmd_off_k(va);
0081     /* Use middle 10 bits of VA to index the second-level map */
0082     if (likely(slab_is_available()))
0083         pg = pte_alloc_kernel(pd, va);
0084     else
0085         pg = early_pte_alloc_kernel(pd, va);
0086     if (pg) {
0087         err = 0;
0088         /* The PTE should never be already set nor present in the
0089          * hash table
0090          */
0091         BUG_ON((pte_present(*pg) | pte_hashpte(*pg)) && pgprot_val(prot));
0092         set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, prot));
0093     }
0094     smp_wmb();
0095     return err;
0096 }
0097
0098 /*
0099  * Map in a chunk of physical memory starting at start.
0100  */
0101 static void __init __mapin_ram_chunk(unsigned long offset, unsigned long top)
0102 {
0103     unsigned long v, s;
0104     phys_addr_t p;
0105     bool ktext;
0106
0107     s = offset;
0108     v = PAGE_OFFSET + s;
0109     p = memstart_addr + s;
0110     for (; s < top; s += PAGE_SIZE) {
0111         ktext = core_kernel_text(v);
0112         map_kernel_page(v, p, ktext ? PAGE_KERNEL_TEXT : PAGE_KERNEL);
0113         v += PAGE_SIZE;
0114         p += PAGE_SIZE;
0115     }
0116 }
0117
0118 void __init mapin_ram(void)
0119 {
0120     phys_addr_t base, end;
0121     u64 i;
0122
0123     for_each_mem_range(i, &base, &end) {
0124         phys_addr_t top = min(end, total_lowmem);
0125
0126         if (base >= top)
0127             continue;
0128         base = mmu_mapin_ram(base, top);
0129         __mapin_ram_chunk(base, top);
0130     }
0131 }
0132
0133 void mark_initmem_nx(void)
0134 {
0135     unsigned long numpages = PFN_UP((unsigned long)_einittext) -
0136                  PFN_DOWN((unsigned long)_sinittext);
0137
0138     mmu_mark_initmem_nx();
0139
0140     if (!v_block_mapped((unsigned long)_sinittext)) {
0141         set_memory_nx((unsigned long)_sinittext, numpages);
0142         set_memory_rw((unsigned long)_sinittext, numpages);
0143     }
0144 }
0145
0146 #ifdef CONFIG_STRICT_KERNEL_RWX
0147 void mark_rodata_ro(void)
0148 {
0149     unsigned long numpages;
0150
0151     if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX) && mmu_has_feature(MMU_FTR_HPTE_TABLE))
0152         pr_warn("This platform has HASH MMU, STRICT_MODULE_RWX won't work\n");
0153
0154     if (v_block_mapped((unsigned long)_stext + 1)) {
0155         mmu_mark_rodata_ro();
0156         ptdump_check_wx();
0157         return;
0158     }
0159
0160     /*
0161      * mark .text and .rodata as read only. Use __init_begin rather than
0162      * __end_rodata to cover NOTES and EXCEPTION_TABLE.
0163      */
0164     numpages = PFN_UP((unsigned long)__init_begin) -
0165            PFN_DOWN((unsigned long)_stext);
0166
0167     set_memory_ro((unsigned long)_stext, numpages);
0168
0169     // mark_initmem_nx() should have already run by now
0170     ptdump_check_wx();
0171 }
0172 #endif
0173
0174 #if defined(CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC) && defined(CONFIG_DEBUG_PAGEALLOC)
0175 void __kernel_map_pages(struct page *page, int numpages, int enable)
0176 {
0177     unsigned long addr = (unsigned long)page_address(page);
0178
0179     if (PageHighMem(page))
0180         return;
0181
0182     if (enable)
0183         set_memory_p(addr, numpages);
0184     else
0185         set_memory_np(addr, numpages);
0186 }
0187 #endif /* CONFIG_DEBUG_PAGEALLOC */