xref: /openbmc/linux/arch/powerpc/mm/copro_fault.c (revision 20e8ef5c)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * CoProcessor (SPU/AFU) mm fault handler
4  *
5  * (C) Copyright IBM Deutschland Entwicklung GmbH 2007
6  *
7  * Author: Arnd Bergmann <arndb@de.ibm.com>
8  * Author: Jeremy Kerr <jk@ozlabs.org>
9  */
10 #include <linux/sched.h>
11 #include <linux/mm.h>
12 #include <linux/export.h>
13 #include <asm/reg.h>
14 #include <asm/copro.h>
15 #include <asm/spu.h>
16 #include <misc/cxl-base.h>
17 
18 /*
19  * This ought to be kept in sync with the powerpc specific do_page_fault
20  * function. Currently, there are a few corner cases that we haven't had
21  * to handle fortunately.
22  */
23 int copro_handle_mm_fault(struct mm_struct *mm, unsigned long ea,
24 		unsigned long dsisr, vm_fault_t *flt)
25 {
26 	struct vm_area_struct *vma;
27 	unsigned long is_write;
28 	int ret;
29 
30 	if (mm == NULL)
31 		return -EFAULT;
32 
33 	if (mm->pgd == NULL)
34 		return -EFAULT;
35 
36 	mmap_read_lock(mm);
37 	ret = -EFAULT;
38 	vma = find_vma(mm, ea);
39 	if (!vma)
40 		goto out_unlock;
41 
42 	if (ea < vma->vm_start) {
43 		if (!(vma->vm_flags & VM_GROWSDOWN))
44 			goto out_unlock;
45 		if (expand_stack(vma, ea))
46 			goto out_unlock;
47 	}
48 
49 	is_write = dsisr & DSISR_ISSTORE;
50 	if (is_write) {
51 		if (!(vma->vm_flags & VM_WRITE))
52 			goto out_unlock;
53 	} else {
54 		if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
55 			goto out_unlock;
56 		/*
57 		 * PROT_NONE is covered by the VMA check above.
58 		 * and hash should get a NOHPTE fault instead of
59 		 * a PROTFAULT in case fixup is needed for things
60 		 * like autonuma.
61 		 */
62 		if (!radix_enabled())
63 			WARN_ON_ONCE(dsisr & DSISR_PROTFAULT);
64 	}
65 
66 	ret = 0;
67 	*flt = handle_mm_fault(vma, ea, is_write ? FAULT_FLAG_WRITE : 0, NULL);
68 	if (unlikely(*flt & VM_FAULT_ERROR)) {
69 		if (*flt & VM_FAULT_OOM) {
70 			ret = -ENOMEM;
71 			goto out_unlock;
72 		} else if (*flt & (VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV)) {
73 			ret = -EFAULT;
74 			goto out_unlock;
75 		}
76 		BUG();
77 	}
78 
79 out_unlock:
80 	mmap_read_unlock(mm);
81 	return ret;
82 }
83 EXPORT_SYMBOL_GPL(copro_handle_mm_fault);
84 
85 #ifdef CONFIG_PPC_64S_HASH_MMU
86 int copro_calculate_slb(struct mm_struct *mm, u64 ea, struct copro_slb *slb)
87 {
88 	u64 vsid, vsidkey;
89 	int psize, ssize;
90 
91 	switch (get_region_id(ea)) {
92 	case USER_REGION_ID:
93 		pr_devel("%s: 0x%llx -- USER_REGION_ID\n", __func__, ea);
94 		if (mm == NULL)
95 			return 1;
96 		psize = get_slice_psize(mm, ea);
97 		ssize = user_segment_size(ea);
98 		vsid = get_user_vsid(&mm->context, ea, ssize);
99 		vsidkey = SLB_VSID_USER;
100 		break;
101 	case VMALLOC_REGION_ID:
102 		pr_devel("%s: 0x%llx -- VMALLOC_REGION_ID\n", __func__, ea);
103 		psize = mmu_vmalloc_psize;
104 		ssize = mmu_kernel_ssize;
105 		vsid = get_kernel_vsid(ea, mmu_kernel_ssize);
106 		vsidkey = SLB_VSID_KERNEL;
107 		break;
108 	case IO_REGION_ID:
109 		pr_devel("%s: 0x%llx -- IO_REGION_ID\n", __func__, ea);
110 		psize = mmu_io_psize;
111 		ssize = mmu_kernel_ssize;
112 		vsid = get_kernel_vsid(ea, mmu_kernel_ssize);
113 		vsidkey = SLB_VSID_KERNEL;
114 		break;
115 	case LINEAR_MAP_REGION_ID:
116 		pr_devel("%s: 0x%llx -- LINEAR_MAP_REGION_ID\n", __func__, ea);
117 		psize = mmu_linear_psize;
118 		ssize = mmu_kernel_ssize;
119 		vsid = get_kernel_vsid(ea, mmu_kernel_ssize);
120 		vsidkey = SLB_VSID_KERNEL;
121 		break;
122 	default:
123 		pr_debug("%s: invalid region access at %016llx\n", __func__, ea);
124 		return 1;
125 	}
126 	/* Bad address */
127 	if (!vsid)
128 		return 1;
129 
130 	vsid = (vsid << slb_vsid_shift(ssize)) | vsidkey;
131 
132 	vsid |= mmu_psize_defs[psize].sllp |
133 		((ssize == MMU_SEGSIZE_1T) ? SLB_VSID_B_1T : 0);
134 
135 	slb->esid = (ea & (ssize == MMU_SEGSIZE_1T ? ESID_MASK_1T : ESID_MASK)) | SLB_ESID_V;
136 	slb->vsid = vsid;
137 
138 	return 0;
139 }
140 EXPORT_SYMBOL_GPL(copro_calculate_slb);
141 
142 void copro_flush_all_slbs(struct mm_struct *mm)
143 {
144 #ifdef CONFIG_SPU_BASE
145 	spu_flush_all_slbs(mm);
146 #endif
147 	cxl_slbia(mm);
148 }
149 EXPORT_SYMBOL_GPL(copro_flush_all_slbs);
150 #endif
151