// SPDX-License-Identifier: GPL-2.0-or-later /* * This file contains the routines for handling the MMU on those * PowerPC implementations where the MMU substantially follows the * architecture specification. This includes the 6xx, 7xx, 7xxx, * and 8260 implementations but excludes the 8xx and 4xx. * -- paulus * * Derived from arch/ppc/mm/init.c: * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) * * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au) * and Cort Dougan (PReP) (cort@cs.nmt.edu) * Copyright (C) 1996 Paul Mackerras * * Derived from "arch/i386/mm/init.c" * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds */ #include #include #include #include #include #include #include #include #include #include #include struct hash_pte *Hash; static unsigned long Hash_size, Hash_mask; unsigned long _SDR1; static unsigned int hash_mb, hash_mb2; struct ppc_bat BATS[8][2]; /* 8 pairs of IBAT, DBAT */ struct batrange { /* stores address ranges mapped by BATs */ unsigned long start; unsigned long limit; phys_addr_t phys; } bat_addrs[8]; /* * Return PA for this VA if it is mapped by a BAT, or 0 */ phys_addr_t v_block_mapped(unsigned long va) { int b; for (b = 0; b < ARRAY_SIZE(bat_addrs); ++b) if (va >= bat_addrs[b].start && va < bat_addrs[b].limit) return bat_addrs[b].phys + (va - bat_addrs[b].start); return 0; } /* * Return VA for a given PA or 0 if not mapped */ unsigned long p_block_mapped(phys_addr_t pa) { int b; for (b = 0; b < ARRAY_SIZE(bat_addrs); ++b) if (pa >= bat_addrs[b].phys && pa < (bat_addrs[b].limit-bat_addrs[b].start) +bat_addrs[b].phys) return bat_addrs[b].start+(pa-bat_addrs[b].phys); return 0; } static int find_free_bat(void) { int b; if (IS_ENABLED(CONFIG_PPC_BOOK3S_601)) { for (b = 0; b < 4; b++) { struct ppc_bat *bat = BATS[b]; if (!(bat[0].batl & 0x40)) return b; } } else { int n = mmu_has_feature(MMU_FTR_USE_HIGH_BATS) ? 8 : 4; for (b = 0; b < n; b++) { struct ppc_bat *bat = BATS[b]; if (!(bat[1].batu & 3)) return b; } } return -1; } /* * This function calculates the size of the larger block usable to map the * beginning of an area based on the start address and size of that area: * - max block size is 8M on 601 and 256 on other 6xx. * - base address must be aligned to the block size. So the maximum block size * is identified by the lowest bit set to 1 in the base address (for instance * if base is 0x16000000, max size is 0x02000000). * - block size has to be a power of two. This is calculated by finding the * highest bit set to 1. */ static unsigned int block_size(unsigned long base, unsigned long top) { unsigned int max_size = IS_ENABLED(CONFIG_PPC_BOOK3S_601) ? SZ_8M : SZ_256M; unsigned int base_shift = (ffs(base) - 1) & 31; unsigned int block_shift = (fls(top - base) - 1) & 31; return min3(max_size, 1U << base_shift, 1U << block_shift); } /* * Set up one of the IBAT (block address translation) register pairs. * The parameters are not checked; in particular size must be a power * of 2 between 128k and 256M. * Only for 603+ ... */ static void setibat(int index, unsigned long virt, phys_addr_t phys, unsigned int size, pgprot_t prot) { unsigned int bl = (size >> 17) - 1; int wimgxpp; struct ppc_bat *bat = BATS[index]; unsigned long flags = pgprot_val(prot); if (!cpu_has_feature(CPU_FTR_NEED_COHERENT)) flags &= ~_PAGE_COHERENT; wimgxpp = (flags & _PAGE_COHERENT) | (_PAGE_EXEC ? BPP_RX : BPP_XX); bat[0].batu = virt | (bl << 2) | 2; /* Vs=1, Vp=0 */ bat[0].batl = BAT_PHYS_ADDR(phys) | wimgxpp; if (flags & _PAGE_USER) bat[0].batu |= 1; /* Vp = 1 */ } static void clearibat(int index) { struct ppc_bat *bat = BATS[index]; bat[0].batu = 0; bat[0].batl = 0; } static unsigned long __init __mmu_mapin_ram(unsigned long base, unsigned long top) { int idx; while ((idx = find_free_bat()) != -1 && base != top) { unsigned int size = block_size(base, top); if (size < 128 << 10) break; setbat(idx, PAGE_OFFSET + base, base, size, PAGE_KERNEL_X); base += size; } return base; } unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top) { unsigned long done; unsigned long border = (unsigned long)__init_begin - PAGE_OFFSET; if (__map_without_bats) { pr_debug("RAM mapped without BATs\n"); return base; } if (debug_pagealloc_enabled()) { if (base >= border) return base; if (top >= border) top = border; } if (!strict_kernel_rwx_enabled() || base >= border || top <= border) return __mmu_mapin_ram(base, top); done = __mmu_mapin_ram(base, border); if (done != border) return done; return __mmu_mapin_ram(border, top); } static bool is_module_segment(unsigned long addr) { if (!IS_ENABLED(CONFIG_MODULES)) return false; if (addr < ALIGN_DOWN(VMALLOC_START, SZ_256M)) return false; if (addr >= ALIGN(VMALLOC_END, SZ_256M)) return false; return true; } void mmu_mark_initmem_nx(void) { int nb = mmu_has_feature(MMU_FTR_USE_HIGH_BATS) ? 8 : 4; int i; unsigned long base = (unsigned long)_stext - PAGE_OFFSET; unsigned long top = (unsigned long)_etext - PAGE_OFFSET; unsigned long border = (unsigned long)__init_begin - PAGE_OFFSET; unsigned long size; if (IS_ENABLED(CONFIG_PPC_BOOK3S_601)) return; for (i = 0; i < nb - 1 && base < top && top - base > (128 << 10);) { size = block_size(base, top); setibat(i++, PAGE_OFFSET + base, base, size, PAGE_KERNEL_TEXT); base += size; } if (base < top) { size = block_size(base, top); size = max(size, 128UL << 10); if ((top - base) > size) { size <<= 1; if (strict_kernel_rwx_enabled() && base + size > border) pr_warn("Some RW data is getting mapped X. " "Adjust CONFIG_DATA_SHIFT to avoid that.\n"); } setibat(i++, PAGE_OFFSET + base, base, size, PAGE_KERNEL_TEXT); base += size; } for (; i < nb; i++) clearibat(i); update_bats(); for (i = TASK_SIZE >> 28; i < 16; i++) { /* Do not set NX on VM space for modules */ if (is_module_segment(i << 28)) continue; mtsrin(mfsrin(i << 28) | 0x10000000, i << 28); } } void mmu_mark_rodata_ro(void) { int nb = mmu_has_feature(MMU_FTR_USE_HIGH_BATS) ? 8 : 4; int i; if (IS_ENABLED(CONFIG_PPC_BOOK3S_601)) return; for (i = 0; i < nb; i++) { struct ppc_bat *bat = BATS[i]; if (bat_addrs[i].start < (unsigned long)__init_begin) bat[1].batl = (bat[1].batl & ~BPP_RW) | BPP_RX; } update_bats(); } /* * Set up one of the I/D BAT (block address translation) register pairs. * The parameters are not checked; in particular size must be a power * of 2 between 128k and 256M. * On 603+, only set IBAT when _PAGE_EXEC is set */ void __init setbat(int index, unsigned long virt, phys_addr_t phys, unsigned int size, pgprot_t prot) { unsigned int bl; int wimgxpp; struct ppc_bat *bat; unsigned long flags = pgprot_val(prot); if (index == -1) index = find_free_bat(); if (index == -1) { pr_err("%s: no BAT available for mapping 0x%llx\n", __func__, (unsigned long long)phys); return; } bat = BATS[index]; if ((flags & _PAGE_NO_CACHE) || (cpu_has_feature(CPU_FTR_NEED_COHERENT) == 0)) flags &= ~_PAGE_COHERENT; bl = (size >> 17) - 1; if (!IS_ENABLED(CONFIG_PPC_BOOK3S_601)) { /* 603, 604, etc. */ /* Do DBAT first */ wimgxpp = flags & (_PAGE_WRITETHRU | _PAGE_NO_CACHE | _PAGE_COHERENT | _PAGE_GUARDED); wimgxpp |= (flags & _PAGE_RW)? BPP_RW: BPP_RX; bat[1].batu = virt | (bl << 2) | 2; /* Vs=1, Vp=0 */ bat[1].batl = BAT_PHYS_ADDR(phys) | wimgxpp; if (flags & _PAGE_USER) bat[1].batu |= 1; /* Vp = 1 */ if (flags & _PAGE_GUARDED) { /* G bit must be zero in IBATs */ flags &= ~_PAGE_EXEC; } if (flags & _PAGE_EXEC) bat[0] = bat[1]; else bat[0].batu = bat[0].batl = 0; } else { /* 601 cpu */ if (bl > BL_8M) bl = BL_8M; wimgxpp = flags & (_PAGE_WRITETHRU | _PAGE_NO_CACHE | _PAGE_COHERENT); wimgxpp |= (flags & _PAGE_RW)? ((flags & _PAGE_USER)? PP_RWRW: PP_RWXX): PP_RXRX; bat->batu = virt | wimgxpp | 4; /* Ks=0, Ku=1 */ bat->batl = phys | bl | 0x40; /* V=1 */ } bat_addrs[index].start = virt; bat_addrs[index].limit = virt + ((bl + 1) << 17) - 1; bat_addrs[index].phys = phys; } /* * Preload a translation in the hash table */ void hash_preload(struct mm_struct *mm, unsigned long ea) { pmd_t *pmd; if (!Hash) return; pmd = pmd_off(mm, ea); if (!pmd_none(*pmd)) add_hash_page(mm->context.id, ea, pmd_val(*pmd)); } /* * This is called at the end of handling a user page fault, when the * fault has been handled by updating a PTE in the linux page tables. * We use it to preload an HPTE into the hash table corresponding to * the updated linux PTE. * * This must always be called with the pte lock held. */ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t *ptep) { if (!mmu_has_feature(MMU_FTR_HPTE_TABLE)) return; /* * We don't need to worry about _PAGE_PRESENT here because we are * called with either mm->page_table_lock held or ptl lock held */ /* We only want HPTEs for linux PTEs that have _PAGE_ACCESSED set */ if (!pte_young(*ptep) || address >= TASK_SIZE) return; /* We have to test for regs NULL since init will get here first thing at boot */ if (!current->thread.regs) return; /* We also avoid filling the hash if not coming from a fault */ if (TRAP(current->thread.regs) != 0x300 && TRAP(current->thread.regs) != 0x400) return; hash_preload(vma->vm_mm, address); } /* * Initialize the hash table and patch the instructions in hashtable.S. */ void __init MMU_init_hw(void) { unsigned int n_hpteg, lg_n_hpteg; if (!mmu_has_feature(MMU_FTR_HPTE_TABLE)) return; if ( ppc_md.progress ) ppc_md.progress("hash:enter", 0x105); #define LG_HPTEG_SIZE 6 /* 64 bytes per HPTEG */ #define SDR1_LOW_BITS ((n_hpteg - 1) >> 10) #define MIN_N_HPTEG 1024 /* min 64kB hash table */ /* * Allow 1 HPTE (1/8 HPTEG) for each page of memory. * This is less than the recommended amount, but then * Linux ain't AIX. */ n_hpteg = total_memory / (PAGE_SIZE * 8); if (n_hpteg < MIN_N_HPTEG) n_hpteg = MIN_N_HPTEG; lg_n_hpteg = __ilog2(n_hpteg); if (n_hpteg & (n_hpteg - 1)) { ++lg_n_hpteg; /* round up if not power of 2 */ n_hpteg = 1 << lg_n_hpteg; } Hash_size = n_hpteg << LG_HPTEG_SIZE; /* * Find some memory for the hash table. */ if ( ppc_md.progress ) ppc_md.progress("hash:find piece", 0x322); Hash = memblock_alloc(Hash_size, Hash_size); if (!Hash) panic("%s: Failed to allocate %lu bytes align=0x%lx\n", __func__, Hash_size, Hash_size); _SDR1 = __pa(Hash) | SDR1_LOW_BITS; pr_info("Total memory = %lldMB; using %ldkB for hash table\n", (unsigned long long)(total_memory >> 20), Hash_size >> 10); Hash_mask = n_hpteg - 1; hash_mb2 = hash_mb = 32 - LG_HPTEG_SIZE - lg_n_hpteg; if (lg_n_hpteg > 16) hash_mb2 = 16 - LG_HPTEG_SIZE; /* * When KASAN is selected, there is already an early temporary hash * table and the switch to the final hash table is done later. */ if (IS_ENABLED(CONFIG_KASAN)) return; MMU_init_hw_patch(); } void __init MMU_init_hw_patch(void) { unsigned int hmask = Hash_mask >> (16 - LG_HPTEG_SIZE); unsigned int hash = (unsigned int)Hash - PAGE_OFFSET; if (ppc_md.progress) ppc_md.progress("hash:patch", 0x345); if (ppc_md.progress) ppc_md.progress("hash:done", 0x205); /* WARNING: Make sure nothing can trigger a KASAN check past this point */ /* * Patch up the instructions in hashtable.S:create_hpte */ modify_instruction_site(&patch__hash_page_A0, 0xffff, hash >> 16); modify_instruction_site(&patch__hash_page_A1, 0x7c0, hash_mb << 6); modify_instruction_site(&patch__hash_page_A2, 0x7c0, hash_mb2 << 6); modify_instruction_site(&patch__hash_page_B, 0xffff, hmask); modify_instruction_site(&patch__hash_page_C, 0xffff, hmask); /* * Patch up the instructions in hashtable.S:flush_hash_page */ modify_instruction_site(&patch__flush_hash_A0, 0xffff, hash >> 16); modify_instruction_site(&patch__flush_hash_A1, 0x7c0, hash_mb << 6); modify_instruction_site(&patch__flush_hash_A2, 0x7c0, hash_mb2 << 6); modify_instruction_site(&patch__flush_hash_B, 0xffff, hmask); } void setup_initial_memory_limit(phys_addr_t first_memblock_base, phys_addr_t first_memblock_size) { /* We don't currently support the first MEMBLOCK not mapping 0 * physical on those processors */ BUG_ON(first_memblock_base != 0); /* 601 can only access 16MB at the moment */ if (IS_ENABLED(CONFIG_PPC_BOOK3S_601)) memblock_set_current_limit(min_t(u64, first_memblock_size, 0x01000000)); else /* Anything else has 256M mapped */ memblock_set_current_limit(min_t(u64, first_memblock_size, 0x10000000)); } void __init print_system_hash_info(void) { pr_info("Hash_size = 0x%lx\n", Hash_size); if (Hash_mask) pr_info("Hash_mask = 0x%lx\n", Hash_mask); } #ifdef CONFIG_PPC_KUEP void __init setup_kuep(bool disabled) { pr_info("Activating Kernel Userspace Execution Prevention\n"); if (disabled) pr_warn("KUEP cannot be disabled yet on 6xx when compiled in\n"); } #endif #ifdef CONFIG_PPC_KUAP void __init setup_kuap(bool disabled) { pr_info("Activating Kernel Userspace Access Protection\n"); if (disabled) pr_warn("KUAP cannot be disabled yet on 6xx when compiled in\n"); } #endif