1 // SPDX-License-Identifier: GPL-2.0-or-later
3  * Copyright 2007-2008 Paul Mackerras, IBM Corp.
22 void subpage_prot_free(struct mm_struct *mm)  in subpage_prot_free()  argument
24 	struct subpage_prot_table *spt = mm_ctx_subpage_prot(&mm->context);  in subpage_prot_free()
31 	for (i = 0; i < 4; ++i) {  in subpage_prot_free()
32 		if (spt->low_prot[i]) {  in subpage_prot_free()
33 			free_page((unsigned long)spt->low_prot[i]);  in subpage_prot_free()
34 			spt->low_prot[i] = NULL;  in subpage_prot_free()
37 	addr = 0;  in subpage_prot_free()
38 	for (i = 0; i < (TASK_SIZE_USER64 >> 43); ++i) {  in subpage_prot_free()
39 		p = spt->protptrs[i];  in subpage_prot_free()
42 		spt->protptrs[i] = NULL;  in subpage_prot_free()
43 		for (j = 0; j < SBP_L2_COUNT && addr < spt->maxaddr;  in subpage_prot_free()
49 	spt->maxaddr = 0;  in subpage_prot_free()
53 static void hpte_flush_range(struct mm_struct *mm, unsigned long addr,  in hpte_flush_range()  argument
63 	pgd = pgd_offset(mm, addr);  in hpte_flush_range()
73 	pte = pte_offset_map_lock(mm, pmd, addr, &ptl);  in hpte_flush_range()
77 	for (; npages > 0; --npages) {  in hpte_flush_range()
78 		pte_update(mm, addr, pte, 0, 0, 0);  in hpte_flush_range()
83 	pte_unmap_unlock(pte - 1, ptl);  in hpte_flush_range()
92 	struct mm_struct *mm = current->mm;  in subpage_prot_clear()  local
99 	mmap_write_lock(mm);  in subpage_prot_clear()
101 	spt = mm_ctx_subpage_prot(&mm->context);  in subpage_prot_clear()
106 	if (limit > spt->maxaddr)  in subpage_prot_clear()
107 		limit = spt->maxaddr;  in subpage_prot_clear()
110 		if (addr < 0x100000000UL) {  in subpage_prot_clear()
111 			spm = spt->low_prot;  in subpage_prot_clear()
113 			spm = spt->protptrs[addr >> SBP_L3_SHIFT];  in subpage_prot_clear()
117 		spp = spm[(addr >> SBP_L2_SHIFT) & (SBP_L2_COUNT - 1)];  in subpage_prot_clear()
120 		spp += (addr >> PAGE_SHIFT) & (SBP_L1_COUNT - 1);  in subpage_prot_clear()
122 		i = (addr >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);  in subpage_prot_clear()
123 		nw = PTRS_PER_PTE - i;  in subpage_prot_clear()
125 			nw = (next - addr) >> PAGE_SHIFT;  in subpage_prot_clear()
127 		memset(spp, 0, nw * sizeof(u32));  in subpage_prot_clear()
130 		hpte_flush_range(mm, addr, nw);  in subpage_prot_clear()
134 	mmap_write_unlock(mm);  in subpage_prot_clear()
141 	struct vm_area_struct *vma = walk->vma;  in subpage_walk_pmd_entry()
143 	return 0;  in subpage_walk_pmd_entry()
151 static void subpage_mark_vma_nohuge(struct mm_struct *mm, unsigned long addr,  in subpage_mark_vma_nohuge()  argument
155 	VMA_ITERATOR(vmi, mm, addr);  in subpage_mark_vma_nohuge()
167 static void subpage_mark_vma_nohuge(struct mm_struct *mm, unsigned long addr,  in subpage_mark_vma_nohuge()  argument
177  * Each 2-bit field is 0 to allow any access, 1 to prevent writes,
180  * protection mechanism is an additional constraint, so putting 0
181  * in a 2-bit field won't allow writes to a page that is otherwise
182  * write-protected.
187 	struct mm_struct *mm = current->mm;  in SYSCALL_DEFINE3()  local
196 		return -ENOENT;  in SYSCALL_DEFINE3()
200 	    addr >= mm->task_size || len >= mm->task_size ||  in SYSCALL_DEFINE3()
201 	    addr + len > mm->task_size)  in SYSCALL_DEFINE3()
202 		return -EINVAL;  in SYSCALL_DEFINE3()
204 	if (is_hugepage_only_range(mm, addr, len))  in SYSCALL_DEFINE3()
205 		return -EINVAL;  in SYSCALL_DEFINE3()
210 		return 0;  in SYSCALL_DEFINE3()
214 		return -EFAULT;  in SYSCALL_DEFINE3()
216 	mmap_write_lock(mm);  in SYSCALL_DEFINE3()
218 	spt = mm_ctx_subpage_prot(&mm->context);  in SYSCALL_DEFINE3()
226 			err = -ENOMEM;  in SYSCALL_DEFINE3()
229 		mm->context.hash_context->spt = spt;  in SYSCALL_DEFINE3()
232 	subpage_mark_vma_nohuge(mm, addr, len);  in SYSCALL_DEFINE3()
235 		err = -ENOMEM;  in SYSCALL_DEFINE3()
236 		if (addr < 0x100000000UL) {  in SYSCALL_DEFINE3()
237 			spm = spt->low_prot;  in SYSCALL_DEFINE3()
239 			spm = spt->protptrs[addr >> SBP_L3_SHIFT];  in SYSCALL_DEFINE3()
244 				spt->protptrs[addr >> SBP_L3_SHIFT] = spm;  in SYSCALL_DEFINE3()
247 		spm += (addr >> SBP_L2_SHIFT) & (SBP_L2_COUNT - 1);  in SYSCALL_DEFINE3()
255 		spp += (addr >> PAGE_SHIFT) & (SBP_L1_COUNT - 1);  in SYSCALL_DEFINE3()
258 		demote_segment_4k(mm, addr);  in SYSCALL_DEFINE3()
261 		i = (addr >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);  in SYSCALL_DEFINE3()
262 		nw = PTRS_PER_PTE - i;  in SYSCALL_DEFINE3()
264 			nw = (next - addr) >> PAGE_SHIFT;  in SYSCALL_DEFINE3()
266 		mmap_write_unlock(mm);  in SYSCALL_DEFINE3()
268 			return -EFAULT;  in SYSCALL_DEFINE3()
270 		mmap_write_lock(mm);  in SYSCALL_DEFINE3()
273 		hpte_flush_range(mm, addr, nw);  in SYSCALL_DEFINE3()
275 	if (limit > spt->maxaddr)  in SYSCALL_DEFINE3()
276 		spt->maxaddr = limit;  in SYSCALL_DEFINE3()
277 	err = 0;  in SYSCALL_DEFINE3()
279 	mmap_write_unlock(mm);  in SYSCALL_DEFINE3()