1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright 2005, Paul Mackerras, IBM Corporation. 4 * Copyright 2009, Benjamin Herrenschmidt, IBM Corporation. 5 * Copyright 2015-2016, Aneesh Kumar K.V, IBM Corporation. 6 */ 7 8 #include <linux/sched.h> 9 #include <linux/memblock.h> 10 #include <asm/pgalloc.h> 11 #include <asm/tlb.h> 12 #include <asm/dma.h> 13 #include <asm/code-patching.h> 14 15 #include <mm/mmu_decl.h> 16 17 #ifdef CONFIG_SPARSEMEM_VMEMMAP 18 /* 19 * On Book3E CPUs, the vmemmap is currently mapped in the top half of 20 * the vmalloc space using normal page tables, though the size of 21 * pages encoded in the PTEs can be different 22 */ 23 int __meminit vmemmap_create_mapping(unsigned long start, 24 unsigned long page_size, 25 unsigned long phys) 26 { 27 /* Create a PTE encoding without page size */ 28 unsigned long i, flags = _PAGE_PRESENT | _PAGE_ACCESSED | 29 _PAGE_KERNEL_RW; 30 31 /* PTEs only contain page size encodings up to 32M */ 32 BUG_ON(mmu_psize_defs[mmu_vmemmap_psize].enc > 0xf); 33 34 /* Encode the size in the PTE */ 35 flags |= mmu_psize_defs[mmu_vmemmap_psize].enc << 8; 36 37 /* For each PTE for that area, map things. Note that we don't 38 * increment phys because all PTEs are of the large size and 39 * thus must have the low bits clear 40 */ 41 for (i = 0; i < page_size; i += PAGE_SIZE) 42 BUG_ON(map_kernel_page(start + i, phys, __pgprot(flags))); 43 44 return 0; 45 } 46 47 #ifdef CONFIG_MEMORY_HOTPLUG 48 void vmemmap_remove_mapping(unsigned long start, 49 unsigned long page_size) 50 { 51 } 52 #endif 53 #endif /* CONFIG_SPARSEMEM_VMEMMAP */ 54 55 static void __init *early_alloc_pgtable(unsigned long size) 56 { 57 void *ptr; 58 59 ptr = memblock_alloc_try_nid(size, size, MEMBLOCK_LOW_LIMIT, 60 __pa(MAX_DMA_ADDRESS), NUMA_NO_NODE); 61 62 if (!ptr) 63 panic("%s: Failed to allocate %lu bytes align=0x%lx max_addr=%lx\n", 64 __func__, size, size, __pa(MAX_DMA_ADDRESS)); 65 66 return ptr; 67 } 68 69 /* 70 * map_kernel_page currently only called by __ioremap 71 * map_kernel_page adds an entry to the ioremap page table 72 * and adds an entry to the HPT, possibly bolting it 73 */ 74 int __ref map_kernel_page(unsigned long ea, unsigned long pa, pgprot_t prot) 75 { 76 pgd_t *pgdp; 77 p4d_t *p4dp; 78 pud_t *pudp; 79 pmd_t *pmdp; 80 pte_t *ptep; 81 82 BUILD_BUG_ON(TASK_SIZE_USER64 > PGTABLE_RANGE); 83 if (slab_is_available()) { 84 pgdp = pgd_offset_k(ea); 85 p4dp = p4d_offset(pgdp, ea); 86 pudp = pud_alloc(&init_mm, p4dp, ea); 87 if (!pudp) 88 return -ENOMEM; 89 pmdp = pmd_alloc(&init_mm, pudp, ea); 90 if (!pmdp) 91 return -ENOMEM; 92 ptep = pte_alloc_kernel(pmdp, ea); 93 if (!ptep) 94 return -ENOMEM; 95 } else { 96 pgdp = pgd_offset_k(ea); 97 p4dp = p4d_offset(pgdp, ea); 98 if (p4d_none(*p4dp)) { 99 pmdp = early_alloc_pgtable(PMD_TABLE_SIZE); 100 p4d_populate(&init_mm, p4dp, pmdp); 101 } 102 pudp = pud_offset(p4dp, ea); 103 if (pud_none(*pudp)) { 104 pmdp = early_alloc_pgtable(PMD_TABLE_SIZE); 105 pud_populate(&init_mm, pudp, pmdp); 106 } 107 pmdp = pmd_offset(pudp, ea); 108 if (!pmd_present(*pmdp)) { 109 ptep = early_alloc_pgtable(PAGE_SIZE); 110 pmd_populate_kernel(&init_mm, pmdp, ptep); 111 } 112 ptep = pte_offset_kernel(pmdp, ea); 113 } 114 set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT, prot)); 115 116 smp_wmb(); 117 return 0; 118 } 119 120 void __patch_exception(int exc, unsigned long addr) 121 { 122 unsigned int *ibase = &interrupt_base_book3e; 123 124 /* 125 * Our exceptions vectors start with a NOP and -then- a branch 126 * to deal with single stepping from userspace which stops on 127 * the second instruction. Thus we need to patch the second 128 * instruction of the exception, not the first one. 129 */ 130 131 patch_branch(ibase + (exc / 4) + 1, addr, 0); 132 } 133