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  */
copro_handle_mm_fault(struct mm_struct * mm,unsigned long ea,unsigned long dsisr,vm_fault_t * flt)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 
copro_calculate_slb(struct mm_struct * mm,u64 ea,struct copro_slb * slb)85 int copro_calculate_slb(struct mm_struct *mm, u64 ea, struct copro_slb *slb)
86 {
87 	u64 vsid, vsidkey;
88 	int psize, ssize;
89 
90 	switch (get_region_id(ea)) {
91 	case USER_REGION_ID:
92 		pr_devel("%s: 0x%llx -- USER_REGION_ID\n", __func__, ea);
93 		if (mm == NULL)
94 			return 1;
95 		psize = get_slice_psize(mm, ea);
96 		ssize = user_segment_size(ea);
97 		vsid = get_user_vsid(&mm->context, ea, ssize);
98 		vsidkey = SLB_VSID_USER;
99 		break;
100 	case VMALLOC_REGION_ID:
101 		pr_devel("%s: 0x%llx -- VMALLOC_REGION_ID\n", __func__, ea);
102 		psize = mmu_vmalloc_psize;
103 		ssize = mmu_kernel_ssize;
104 		vsid = get_kernel_vsid(ea, mmu_kernel_ssize);
105 		vsidkey = SLB_VSID_KERNEL;
106 		break;
107 	case IO_REGION_ID:
108 		pr_devel("%s: 0x%llx -- IO_REGION_ID\n", __func__, ea);
109 		psize = mmu_io_psize;
110 		ssize = mmu_kernel_ssize;
111 		vsid = get_kernel_vsid(ea, mmu_kernel_ssize);
112 		vsidkey = SLB_VSID_KERNEL;
113 		break;
114 	case LINEAR_MAP_REGION_ID:
115 		pr_devel("%s: 0x%llx -- LINEAR_MAP_REGION_ID\n", __func__, ea);
116 		psize = mmu_linear_psize;
117 		ssize = mmu_kernel_ssize;
118 		vsid = get_kernel_vsid(ea, mmu_kernel_ssize);
119 		vsidkey = SLB_VSID_KERNEL;
120 		break;
121 	default:
122 		pr_debug("%s: invalid region access at %016llx\n", __func__, ea);
123 		return 1;
124 	}
125 	/* Bad address */
126 	if (!vsid)
127 		return 1;
128 
129 	vsid = (vsid << slb_vsid_shift(ssize)) | vsidkey;
130 
131 	vsid |= mmu_psize_defs[psize].sllp |
132 		((ssize == MMU_SEGSIZE_1T) ? SLB_VSID_B_1T : 0);
133 
134 	slb->esid = (ea & (ssize == MMU_SEGSIZE_1T ? ESID_MASK_1T : ESID_MASK)) | SLB_ESID_V;
135 	slb->vsid = vsid;
136 
137 	return 0;
138 }
139 EXPORT_SYMBOL_GPL(copro_calculate_slb);
140 
copro_flush_all_slbs(struct mm_struct * mm)141 void copro_flush_all_slbs(struct mm_struct *mm)
142 {
143 #ifdef CONFIG_SPU_BASE
144 	spu_flush_all_slbs(mm);
145 #endif
146 	cxl_slbia(mm);
147 }
148 EXPORT_SYMBOL_GPL(copro_flush_all_slbs);
149