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 */
23int __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
48void vmemmap_remove_mapping(unsigned long start,
49			    unsigned long page_size)
50{
51}
52#endif
53#endif /* CONFIG_SPARSEMEM_VMEMMAP */
54
55static 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 */
74int __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			pudp = early_alloc_pgtable(PUD_TABLE_SIZE);
100			p4d_populate(&init_mm, p4dp, pudp);
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(PTE_TABLE_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
120void __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