1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * xtensa mmu stuff 4 * 5 * Extracted from init.c 6 */ 7 #include <linux/memblock.h> 8 #include <linux/percpu.h> 9 #include <linux/init.h> 10 #include <linux/string.h> 11 #include <linux/slab.h> 12 #include <linux/cache.h> 13 14 #include <asm/tlb.h> 15 #include <asm/tlbflush.h> 16 #include <asm/mmu_context.h> 17 #include <asm/page.h> 18 #include <asm/initialize_mmu.h> 19 #include <asm/io.h> 20 21 #if defined(CONFIG_HIGHMEM) 22 static void * __init init_pmd(unsigned long vaddr, unsigned long n_pages) 23 { 24 pgd_t *pgd = pgd_offset_k(vaddr); 25 p4d_t *p4d = p4d_offset(pgd, vaddr); 26 pud_t *pud = pud_offset(p4d, vaddr); 27 pmd_t *pmd = pmd_offset(pud, vaddr); 28 pte_t *pte; 29 unsigned long i; 30 31 n_pages = ALIGN(n_pages, PTRS_PER_PTE); 32 33 pr_debug("%s: vaddr: 0x%08lx, n_pages: %ld\n", 34 __func__, vaddr, n_pages); 35 36 pte = memblock_alloc_low(n_pages * sizeof(pte_t), PAGE_SIZE); 37 if (!pte) 38 panic("%s: Failed to allocate %lu bytes align=%lx\n", 39 __func__, n_pages * sizeof(pte_t), PAGE_SIZE); 40 41 for (i = 0; i < n_pages; ++i) 42 pte_clear(NULL, 0, pte + i); 43 44 for (i = 0; i < n_pages; i += PTRS_PER_PTE, ++pmd) { 45 pte_t *cur_pte = pte + i; 46 47 BUG_ON(!pmd_none(*pmd)); 48 set_pmd(pmd, __pmd(((unsigned long)cur_pte) & PAGE_MASK)); 49 BUG_ON(cur_pte != pte_offset_kernel(pmd, 0)); 50 pr_debug("%s: pmd: 0x%p, pte: 0x%p\n", 51 __func__, pmd, cur_pte); 52 } 53 return pte; 54 } 55 56 static void __init fixedrange_init(void) 57 { 58 init_pmd(__fix_to_virt(0), __end_of_fixed_addresses); 59 } 60 #endif 61 62 void __init paging_init(void) 63 { 64 #ifdef CONFIG_HIGHMEM 65 fixedrange_init(); 66 pkmap_page_table = init_pmd(PKMAP_BASE, LAST_PKMAP); 67 kmap_init(); 68 #endif 69 } 70 71 /* 72 * Flush the mmu and reset associated register to default values. 73 */ 74 void init_mmu(void) 75 { 76 #if !(XCHAL_HAVE_PTP_MMU && XCHAL_HAVE_SPANNING_WAY) 77 /* 78 * Writing zeros to the instruction and data TLBCFG special 79 * registers ensure that valid values exist in the register. 80 * 81 * For existing PGSZID<w> fields, zero selects the first element 82 * of the page-size array. For nonexistent PGSZID<w> fields, 83 * zero is the best value to write. Also, when changing PGSZID<w> 84 * fields, the corresponding TLB must be flushed. 85 */ 86 set_itlbcfg_register(0); 87 set_dtlbcfg_register(0); 88 #endif 89 init_kio(); 90 local_flush_tlb_all(); 91 92 /* Set rasid register to a known value. */ 93 94 set_rasid_register(ASID_INSERT(ASID_USER_FIRST)); 95 96 /* Set PTEVADDR special register to the start of the page 97 * table, which is in kernel mappable space (ie. not 98 * statically mapped). This register's value is undefined on 99 * reset. 100 */ 101 set_ptevaddr_register(XCHAL_PAGE_TABLE_VADDR); 102 } 103 104 void init_kio(void) 105 { 106 #if XCHAL_HAVE_PTP_MMU && XCHAL_HAVE_SPANNING_WAY && defined(CONFIG_OF) 107 /* 108 * Update the IO area mapping in case xtensa_kio_paddr has changed 109 */ 110 write_dtlb_entry(__pte(xtensa_kio_paddr + CA_WRITEBACK), 111 XCHAL_KIO_CACHED_VADDR + 6); 112 write_itlb_entry(__pte(xtensa_kio_paddr + CA_WRITEBACK), 113 XCHAL_KIO_CACHED_VADDR + 6); 114 write_dtlb_entry(__pte(xtensa_kio_paddr + CA_BYPASS), 115 XCHAL_KIO_BYPASS_VADDR + 6); 116 write_itlb_entry(__pte(xtensa_kio_paddr + CA_BYPASS), 117 XCHAL_KIO_BYPASS_VADDR + 6); 118 #endif 119 } 120