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0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * Copyright IBM Corp. 2011
0004  * Author(s): Jan Glauber <jang@linux.vnet.ibm.com>
0005  */
0006 #include <linux/hugetlb.h>
0007 #include <linux/mm.h>
0008 #include <asm/cacheflush.h>
0009 #include <asm/facility.h>
0010 #include <asm/pgalloc.h>
0011 #include <asm/kfence.h>
0012 #include <asm/page.h>
0013 #include <asm/set_memory.h>
0014 
0015 static inline unsigned long sske_frame(unsigned long addr, unsigned char skey)
0016 {
0017     asm volatile(".insn rrf,0xb22b0000,%[skey],%[addr],1,0"
0018              : [addr] "+a" (addr) : [skey] "d" (skey));
0019     return addr;
0020 }
0021 
0022 void __storage_key_init_range(unsigned long start, unsigned long end)
0023 {
0024     unsigned long boundary, size;
0025 
0026     while (start < end) {
0027         if (MACHINE_HAS_EDAT1) {
0028             /* set storage keys for a 1MB frame */
0029             size = 1UL << 20;
0030             boundary = (start + size) & ~(size - 1);
0031             if (boundary <= end) {
0032                 do {
0033                     start = sske_frame(start, PAGE_DEFAULT_KEY);
0034                 } while (start < boundary);
0035                 continue;
0036             }
0037         }
0038         page_set_storage_key(start, PAGE_DEFAULT_KEY, 1);
0039         start += PAGE_SIZE;
0040     }
0041 }
0042 
0043 #ifdef CONFIG_PROC_FS
0044 atomic_long_t direct_pages_count[PG_DIRECT_MAP_MAX];
0045 
0046 void arch_report_meminfo(struct seq_file *m)
0047 {
0048     seq_printf(m, "DirectMap4k:    %8lu kB\n",
0049            atomic_long_read(&direct_pages_count[PG_DIRECT_MAP_4K]) << 2);
0050     seq_printf(m, "DirectMap1M:    %8lu kB\n",
0051            atomic_long_read(&direct_pages_count[PG_DIRECT_MAP_1M]) << 10);
0052     seq_printf(m, "DirectMap2G:    %8lu kB\n",
0053            atomic_long_read(&direct_pages_count[PG_DIRECT_MAP_2G]) << 21);
0054 }
0055 #endif /* CONFIG_PROC_FS */
0056 
0057 static void pgt_set(unsigned long *old, unsigned long new, unsigned long addr,
0058             unsigned long dtt)
0059 {
0060     unsigned long *table, mask;
0061 
0062     mask = 0;
0063     if (MACHINE_HAS_EDAT2) {
0064         switch (dtt) {
0065         case CRDTE_DTT_REGION3:
0066             mask = ~(PTRS_PER_PUD * sizeof(pud_t) - 1);
0067             break;
0068         case CRDTE_DTT_SEGMENT:
0069             mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
0070             break;
0071         case CRDTE_DTT_PAGE:
0072             mask = ~(PTRS_PER_PTE * sizeof(pte_t) - 1);
0073             break;
0074         }
0075         table = (unsigned long *)((unsigned long)old & mask);
0076         crdte(*old, new, table, dtt, addr, S390_lowcore.kernel_asce);
0077     } else if (MACHINE_HAS_IDTE) {
0078         cspg(old, *old, new);
0079     } else {
0080         csp((unsigned int *)old + 1, *old, new);
0081     }
0082 }
0083 
0084 static int walk_pte_level(pmd_t *pmdp, unsigned long addr, unsigned long end,
0085               unsigned long flags)
0086 {
0087     pte_t *ptep, new;
0088 
0089     if (flags == SET_MEMORY_4K)
0090         return 0;
0091     ptep = pte_offset_kernel(pmdp, addr);
0092     do {
0093         new = *ptep;
0094         if (pte_none(new))
0095             return -EINVAL;
0096         if (flags & SET_MEMORY_RO)
0097             new = pte_wrprotect(new);
0098         else if (flags & SET_MEMORY_RW)
0099             new = pte_mkwrite(pte_mkdirty(new));
0100         if (flags & SET_MEMORY_NX)
0101             new = set_pte_bit(new, __pgprot(_PAGE_NOEXEC));
0102         else if (flags & SET_MEMORY_X)
0103             new = clear_pte_bit(new, __pgprot(_PAGE_NOEXEC));
0104         pgt_set((unsigned long *)ptep, pte_val(new), addr, CRDTE_DTT_PAGE);
0105         ptep++;
0106         addr += PAGE_SIZE;
0107         cond_resched();
0108     } while (addr < end);
0109     return 0;
0110 }
0111 
0112 static int split_pmd_page(pmd_t *pmdp, unsigned long addr)
0113 {
0114     unsigned long pte_addr, prot;
0115     pte_t *pt_dir, *ptep;
0116     pmd_t new;
0117     int i, ro, nx;
0118 
0119     pt_dir = vmem_pte_alloc();
0120     if (!pt_dir)
0121         return -ENOMEM;
0122     pte_addr = pmd_pfn(*pmdp) << PAGE_SHIFT;
0123     ro = !!(pmd_val(*pmdp) & _SEGMENT_ENTRY_PROTECT);
0124     nx = !!(pmd_val(*pmdp) & _SEGMENT_ENTRY_NOEXEC);
0125     prot = pgprot_val(ro ? PAGE_KERNEL_RO : PAGE_KERNEL);
0126     if (!nx)
0127         prot &= ~_PAGE_NOEXEC;
0128     ptep = pt_dir;
0129     for (i = 0; i < PTRS_PER_PTE; i++) {
0130         set_pte(ptep, __pte(pte_addr | prot));
0131         pte_addr += PAGE_SIZE;
0132         ptep++;
0133     }
0134     new = __pmd(__pa(pt_dir) | _SEGMENT_ENTRY);
0135     pgt_set((unsigned long *)pmdp, pmd_val(new), addr, CRDTE_DTT_SEGMENT);
0136     update_page_count(PG_DIRECT_MAP_4K, PTRS_PER_PTE);
0137     update_page_count(PG_DIRECT_MAP_1M, -1);
0138     return 0;
0139 }
0140 
0141 static void modify_pmd_page(pmd_t *pmdp, unsigned long addr,
0142                 unsigned long flags)
0143 {
0144     pmd_t new = *pmdp;
0145 
0146     if (flags & SET_MEMORY_RO)
0147         new = pmd_wrprotect(new);
0148     else if (flags & SET_MEMORY_RW)
0149         new = pmd_mkwrite(pmd_mkdirty(new));
0150     if (flags & SET_MEMORY_NX)
0151         new = set_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_NOEXEC));
0152     else if (flags & SET_MEMORY_X)
0153         new = clear_pmd_bit(new, __pgprot(_SEGMENT_ENTRY_NOEXEC));
0154     pgt_set((unsigned long *)pmdp, pmd_val(new), addr, CRDTE_DTT_SEGMENT);
0155 }
0156 
0157 static int walk_pmd_level(pud_t *pudp, unsigned long addr, unsigned long end,
0158               unsigned long flags)
0159 {
0160     unsigned long next;
0161     int need_split;
0162     pmd_t *pmdp;
0163     int rc = 0;
0164 
0165     pmdp = pmd_offset(pudp, addr);
0166     do {
0167         if (pmd_none(*pmdp))
0168             return -EINVAL;
0169         next = pmd_addr_end(addr, end);
0170         if (pmd_large(*pmdp)) {
0171             need_split  = !!(flags & SET_MEMORY_4K);
0172             need_split |= !!(addr & ~PMD_MASK);
0173             need_split |= !!(addr + PMD_SIZE > next);
0174             if (need_split) {
0175                 rc = split_pmd_page(pmdp, addr);
0176                 if (rc)
0177                     return rc;
0178                 continue;
0179             }
0180             modify_pmd_page(pmdp, addr, flags);
0181         } else {
0182             rc = walk_pte_level(pmdp, addr, next, flags);
0183             if (rc)
0184                 return rc;
0185         }
0186         pmdp++;
0187         addr = next;
0188         cond_resched();
0189     } while (addr < end);
0190     return rc;
0191 }
0192 
0193 static int split_pud_page(pud_t *pudp, unsigned long addr)
0194 {
0195     unsigned long pmd_addr, prot;
0196     pmd_t *pm_dir, *pmdp;
0197     pud_t new;
0198     int i, ro, nx;
0199 
0200     pm_dir = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
0201     if (!pm_dir)
0202         return -ENOMEM;
0203     pmd_addr = pud_pfn(*pudp) << PAGE_SHIFT;
0204     ro = !!(pud_val(*pudp) & _REGION_ENTRY_PROTECT);
0205     nx = !!(pud_val(*pudp) & _REGION_ENTRY_NOEXEC);
0206     prot = pgprot_val(ro ? SEGMENT_KERNEL_RO : SEGMENT_KERNEL);
0207     if (!nx)
0208         prot &= ~_SEGMENT_ENTRY_NOEXEC;
0209     pmdp = pm_dir;
0210     for (i = 0; i < PTRS_PER_PMD; i++) {
0211         set_pmd(pmdp, __pmd(pmd_addr | prot));
0212         pmd_addr += PMD_SIZE;
0213         pmdp++;
0214     }
0215     new = __pud(__pa(pm_dir) | _REGION3_ENTRY);
0216     pgt_set((unsigned long *)pudp, pud_val(new), addr, CRDTE_DTT_REGION3);
0217     update_page_count(PG_DIRECT_MAP_1M, PTRS_PER_PMD);
0218     update_page_count(PG_DIRECT_MAP_2G, -1);
0219     return 0;
0220 }
0221 
0222 static void modify_pud_page(pud_t *pudp, unsigned long addr,
0223                 unsigned long flags)
0224 {
0225     pud_t new = *pudp;
0226 
0227     if (flags & SET_MEMORY_RO)
0228         new = pud_wrprotect(new);
0229     else if (flags & SET_MEMORY_RW)
0230         new = pud_mkwrite(pud_mkdirty(new));
0231     if (flags & SET_MEMORY_NX)
0232         new = set_pud_bit(new, __pgprot(_REGION_ENTRY_NOEXEC));
0233     else if (flags & SET_MEMORY_X)
0234         new = clear_pud_bit(new, __pgprot(_REGION_ENTRY_NOEXEC));
0235     pgt_set((unsigned long *)pudp, pud_val(new), addr, CRDTE_DTT_REGION3);
0236 }
0237 
0238 static int walk_pud_level(p4d_t *p4d, unsigned long addr, unsigned long end,
0239               unsigned long flags)
0240 {
0241     unsigned long next;
0242     int need_split;
0243     pud_t *pudp;
0244     int rc = 0;
0245 
0246     pudp = pud_offset(p4d, addr);
0247     do {
0248         if (pud_none(*pudp))
0249             return -EINVAL;
0250         next = pud_addr_end(addr, end);
0251         if (pud_large(*pudp)) {
0252             need_split  = !!(flags & SET_MEMORY_4K);
0253             need_split |= !!(addr & ~PUD_MASK);
0254             need_split |= !!(addr + PUD_SIZE > next);
0255             if (need_split) {
0256                 rc = split_pud_page(pudp, addr);
0257                 if (rc)
0258                     break;
0259                 continue;
0260             }
0261             modify_pud_page(pudp, addr, flags);
0262         } else {
0263             rc = walk_pmd_level(pudp, addr, next, flags);
0264         }
0265         pudp++;
0266         addr = next;
0267         cond_resched();
0268     } while (addr < end && !rc);
0269     return rc;
0270 }
0271 
0272 static int walk_p4d_level(pgd_t *pgd, unsigned long addr, unsigned long end,
0273               unsigned long flags)
0274 {
0275     unsigned long next;
0276     p4d_t *p4dp;
0277     int rc = 0;
0278 
0279     p4dp = p4d_offset(pgd, addr);
0280     do {
0281         if (p4d_none(*p4dp))
0282             return -EINVAL;
0283         next = p4d_addr_end(addr, end);
0284         rc = walk_pud_level(p4dp, addr, next, flags);
0285         p4dp++;
0286         addr = next;
0287         cond_resched();
0288     } while (addr < end && !rc);
0289     return rc;
0290 }
0291 
0292 DEFINE_MUTEX(cpa_mutex);
0293 
0294 static int change_page_attr(unsigned long addr, unsigned long end,
0295                 unsigned long flags)
0296 {
0297     unsigned long next;
0298     int rc = -EINVAL;
0299     pgd_t *pgdp;
0300 
0301     if (addr == end)
0302         return 0;
0303     if (end >= MODULES_END)
0304         return -EINVAL;
0305     mutex_lock(&cpa_mutex);
0306     pgdp = pgd_offset_k(addr);
0307     do {
0308         if (pgd_none(*pgdp))
0309             break;
0310         next = pgd_addr_end(addr, end);
0311         rc = walk_p4d_level(pgdp, addr, next, flags);
0312         if (rc)
0313             break;
0314         cond_resched();
0315     } while (pgdp++, addr = next, addr < end && !rc);
0316     mutex_unlock(&cpa_mutex);
0317     return rc;
0318 }
0319 
0320 int __set_memory(unsigned long addr, int numpages, unsigned long flags)
0321 {
0322     if (!MACHINE_HAS_NX)
0323         flags &= ~(SET_MEMORY_NX | SET_MEMORY_X);
0324     if (!flags)
0325         return 0;
0326     addr &= PAGE_MASK;
0327     return change_page_attr(addr, addr + numpages * PAGE_SIZE, flags);
0328 }
0329 
0330 #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE)
0331 
0332 static void ipte_range(pte_t *pte, unsigned long address, int nr)
0333 {
0334     int i;
0335 
0336     if (test_facility(13)) {
0337         __ptep_ipte_range(address, nr - 1, pte, IPTE_GLOBAL);
0338         return;
0339     }
0340     for (i = 0; i < nr; i++) {
0341         __ptep_ipte(address, pte, 0, 0, IPTE_GLOBAL);
0342         address += PAGE_SIZE;
0343         pte++;
0344     }
0345 }
0346 
0347 void __kernel_map_pages(struct page *page, int numpages, int enable)
0348 {
0349     unsigned long address;
0350     pte_t *ptep, pte;
0351     int nr, i, j;
0352 
0353     for (i = 0; i < numpages;) {
0354         address = (unsigned long)page_to_virt(page + i);
0355         ptep = virt_to_kpte(address);
0356         nr = (unsigned long)ptep >> ilog2(sizeof(long));
0357         nr = PTRS_PER_PTE - (nr & (PTRS_PER_PTE - 1));
0358         nr = min(numpages - i, nr);
0359         if (enable) {
0360             for (j = 0; j < nr; j++) {
0361                 pte = clear_pte_bit(*ptep, __pgprot(_PAGE_INVALID));
0362                 set_pte(ptep, pte);
0363                 address += PAGE_SIZE;
0364                 ptep++;
0365             }
0366         } else {
0367             ipte_range(ptep, address, nr);
0368         }
0369         i += nr;
0370     }
0371 }
0372 
0373 #endif /* CONFIG_DEBUG_PAGEALLOC */
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