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
14#include <mm/mmu_decl.h>
15
16#ifdef CONFIG_SPARSEMEM_VMEMMAP
17/*
18 * On Book3E CPUs, the vmemmap is currently mapped in the top half of
19 * the vmalloc space using normal page tables, though the size of
20 * pages encoded in the PTEs can be different
21 */
22int __meminit vmemmap_create_mapping(unsigned long start,
23				     unsigned long page_size,
24				     unsigned long phys)
25{
26	/* Create a PTE encoding without page size */
27	unsigned long i, flags = _PAGE_PRESENT | _PAGE_ACCESSED |
28		_PAGE_KERNEL_RW;
29
30	/* PTEs only contain page size encodings up to 32M */
31	BUG_ON(mmu_psize_defs[mmu_vmemmap_psize].enc > 0xf);
32
33	/* Encode the size in the PTE */
34	flags |= mmu_psize_defs[mmu_vmemmap_psize].enc << 8;
35
36	/* For each PTE for that area, map things. Note that we don't
37	 * increment phys because all PTEs are of the large size and
38	 * thus must have the low bits clear
39	 */
40	for (i = 0; i < page_size; i += PAGE_SIZE)
41		BUG_ON(map_kernel_page(start + i, phys, __pgprot(flags)));
42
43	return 0;
44}
45
46#ifdef CONFIG_MEMORY_HOTPLUG
47void vmemmap_remove_mapping(unsigned long start,
48			    unsigned long page_size)
49{
50}
51#endif
52#endif /* CONFIG_SPARSEMEM_VMEMMAP */
53
54static void __init *early_alloc_pgtable(unsigned long size)
55{
56	void *ptr;
57
58	ptr = memblock_alloc_try_nid(size, size, MEMBLOCK_LOW_LIMIT,
59				     __pa(MAX_DMA_ADDRESS), NUMA_NO_NODE);
60
61	if (!ptr)
62		panic("%s: Failed to allocate %lu bytes align=0x%lx max_addr=%lx\n",
63		      __func__, size, size, __pa(MAX_DMA_ADDRESS));
64
65	return ptr;
66}
67
68/*
69 * map_kernel_page currently only called by __ioremap
70 * map_kernel_page adds an entry to the ioremap page table
71 * and adds an entry to the HPT, possibly bolting it
72 */
73int __ref map_kernel_page(unsigned long ea, unsigned long pa, pgprot_t prot)
74{
75	pgd_t *pgdp;
76	p4d_t *p4dp;
77	pud_t *pudp;
78	pmd_t *pmdp;
79	pte_t *ptep;
80
81	BUILD_BUG_ON(TASK_SIZE_USER64 > PGTABLE_RANGE);
82	if (slab_is_available()) {
83		pgdp = pgd_offset_k(ea);
84		p4dp = p4d_offset(pgdp, ea);
85		pudp = pud_alloc(&init_mm, p4dp, ea);
86		if (!pudp)
87			return -ENOMEM;
88		pmdp = pmd_alloc(&init_mm, pudp, ea);
89		if (!pmdp)
90			return -ENOMEM;
91		ptep = pte_alloc_kernel(pmdp, ea);
92		if (!ptep)
93			return -ENOMEM;
94	} else {
95		pgdp = pgd_offset_k(ea);
96		p4dp = p4d_offset(pgdp, ea);
97		if (p4d_none(*p4dp)) {
98			pudp = early_alloc_pgtable(PUD_TABLE_SIZE);
99			p4d_populate(&init_mm, p4dp, pudp);
100		}
101		pudp = pud_offset(p4dp, ea);
102		if (pud_none(*pudp)) {
103			pmdp = early_alloc_pgtable(PMD_TABLE_SIZE);
104			pud_populate(&init_mm, pudp, pmdp);
105		}
106		pmdp = pmd_offset(pudp, ea);
107		if (!pmd_present(*pmdp)) {
108			ptep = early_alloc_pgtable(PTE_TABLE_SIZE);
109			pmd_populate_kernel(&init_mm, pmdp, ptep);
110		}
111		ptep = pte_offset_kernel(pmdp, ea);
112	}
113	set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT, prot));
114
115	smp_wmb();
116	return 0;
117}
118