gpiolib: cdev: fix null pointer dereference in linereq_free()
[linux-block.git] / arch / powerpc / mm / nohash / book3e_pgtable.c
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 }