diff options
Diffstat (limited to 'arch/powerpc/mm/book3s32/mmu.c')
-rw-r--r-- | arch/powerpc/mm/book3s32/mmu.c | 444 |
1 files changed, 444 insertions, 0 deletions
diff --git a/arch/powerpc/mm/book3s32/mmu.c b/arch/powerpc/mm/book3s32/mmu.c new file mode 100644 index 0000000000..850783cfa9 --- /dev/null +++ b/arch/powerpc/mm/book3s32/mmu.c @@ -0,0 +1,444 @@ +// 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 <linux/kernel.h> +#include <linux/mm.h> +#include <linux/init.h> +#include <linux/highmem.h> +#include <linux/memblock.h> + +#include <asm/mmu.h> +#include <asm/machdep.h> +#include <asm/code-patching.h> +#include <asm/sections.h> + +#include <mm/mmu_decl.h> + +u8 __initdata early_hash[SZ_256K] __aligned(SZ_256K) = {0}; + +static struct hash_pte __initdata *Hash = (struct hash_pte *)early_hash; +static unsigned long __initdata Hash_size, Hash_mask; +static unsigned int __initdata hash_mb, hash_mb2; +unsigned long __initdata _SDR1; + +struct ppc_bat BATS[8][2]; /* 8 pairs of IBAT, DBAT */ + +static struct batrange { /* stores address ranges mapped by BATs */ + unsigned long start; + unsigned long limit; + phys_addr_t phys; +} bat_addrs[8]; + +#ifdef CONFIG_SMP +unsigned long mmu_hash_lock; +#endif + +/* + * 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; +} + +int __init find_free_bat(void) +{ + int b; + 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 256 on 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. + */ +unsigned int bat_block_size(unsigned long base, unsigned long top) +{ + unsigned int max_size = 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. + */ +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 = bat_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)__srwx_boundary - PAGE_OFFSET; + unsigned long size; + + size = roundup_pow_of_two((unsigned long)_einittext - PAGE_OFFSET); + setibat(0, PAGE_OFFSET, 0, size, PAGE_KERNEL_X); + + if (debug_pagealloc_enabled_or_kfence()) { + pr_debug_once("Read-Write memory mapped without BATs\n"); + 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(MODULES_VADDR, SZ_256M)) + return false; + if (addr > ALIGN(MODULES_END, SZ_256M) - 1) + 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 = ALIGN((unsigned long)_etext - PAGE_OFFSET, SZ_128K); + unsigned long border = (unsigned long)__init_begin - PAGE_OFFSET; + unsigned long size; + + for (i = 0; i < nb - 1 && base < top;) { + size = bat_block_size(base, top); + setibat(i++, PAGE_OFFSET + base, base, size, PAGE_KERNEL_TEXT); + base += size; + } + if (base < top) { + size = bat_block_size(base, top); + 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; + + mtsr(mfsr(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; + + for (i = 0; i < nb; i++) { + struct ppc_bat *bat = BATS[i]; + + if (bat_addrs[i].start < (unsigned long)__end_rodata) + bat[1].batl = (bat[1].batl & ~BPP_RW) | BPP_RX; + } + + update_bats(); +} + +/* + * Set up one of the 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. + */ +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; + /* 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; + } + + 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 + */ +static void hash_preload(struct mm_struct *mm, unsigned long ea) +{ + pmd_t *pmd; + + if (!mmu_has_feature(MMU_FTR_HPTE_TABLE)) + 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) +{ + /* + * 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; +} + +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 (!mmu_has_feature(MMU_FTR_HPTE_TABLE)) + return; + + 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); + + memblock_set_current_limit(min_t(u64, first_memblock_size, SZ_256M)); +} + +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); +} + +void __init early_init_mmu(void) +{ +} |