diff options
Diffstat (limited to 'payloads/libpayload/arch/arm64/mmu.c')
| -rw-r--r-- | payloads/libpayload/arch/arm64/mmu.c | 618 |
1 files changed, 618 insertions, 0 deletions
diff --git a/payloads/libpayload/arch/arm64/mmu.c b/payloads/libpayload/arch/arm64/mmu.c new file mode 100644 index 000000000000..85f3ac9a5666 --- /dev/null +++ b/payloads/libpayload/arch/arm64/mmu.c @@ -0,0 +1,618 @@ +/* + * This file is part of the coreboot project. + * + * Copyright 2014 Google Inc. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <assert.h> +#include <stdlib.h> +#include <stdint.h> +#include <string.h> + +#include <arch/mmu.h> +#include <arch/lib_helpers.h> +#include <arch/cache.h> + +/* Maximum number of XLAT Tables available based on ttb buffer size */ +static unsigned int max_tables; +/* Address of ttb buffer */ +static uint64_t *xlat_addr; + +static int free_idx; +static uint8_t ttb_buffer[TTB_DEFAULT_SIZE] __attribute__((aligned(GRANULE_SIZE))); + +/* + * The usedmem_ranges is used to describe all the memory ranges that are + * actually used by payload i.e. _start -> _end in linker script and the + * coreboot tables. This is required for two purposes: + * 1) During the pre_sysinfo_scan_mmu_setup, these are the only ranges + * initialized in the page table as we do not know the entire memory map. + * 2) During the post_sysinfo_scan_mmu_setup, these ranges are used to check if + * the DMA buffer is being placed in a sane location and does not overlap any of + * the used mem ranges. + */ +struct mmu_ranges usedmem_ranges; + +static const uint64_t level_to_addr_mask[] = { + L1_ADDR_MASK, + L2_ADDR_MASK, + L3_ADDR_MASK, +}; + +static const uint64_t level_to_addr_shift[] = { + L1_ADDR_SHIFT, + L2_ADDR_SHIFT, + L3_ADDR_SHIFT, +}; + +static void __attribute__((noreturn)) mmu_error(void) +{ + halt(); +} + +/* + * Func : get_block_attr + * Desc : Get block descriptor attributes based on the value of tag in memrange + * region + */ +static uint64_t get_block_attr(unsigned long tag) +{ + uint64_t attr; + + /* We should be in EL2(which is non-secure only) or EL1(non-secure) */ + attr = BLOCK_NS; + + /* Assuming whole memory is read-write */ + attr |= BLOCK_AP_RW; + + attr |= BLOCK_ACCESS; + + switch (tag) { + + case TYPE_NORMAL_MEM: + attr |= (BLOCK_INDEX_MEM_NORMAL << BLOCK_INDEX_SHIFT); + break; + case TYPE_DEV_MEM: + attr |= BLOCK_INDEX_MEM_DEV_NGNRNE << BLOCK_INDEX_SHIFT; + break; + case TYPE_DMA_MEM: + attr |= BLOCK_INDEX_MEM_NORMAL_NC << BLOCK_INDEX_SHIFT; + break; + } + + return attr; +} + +/* + * Func : get_index_from_addr + * Desc : Get index into table at a given level using appropriate bits from the + * base address + */ +static uint64_t get_index_from_addr(uint64_t addr, uint8_t level) +{ + uint64_t mask = level_to_addr_mask[level-1]; + uint8_t shift = level_to_addr_shift[level-1]; + + return ((addr & mask) >> shift); +} + +/* + * Func : table_desc_valid + * Desc : Check if a table entry contains valid desc + */ +static uint64_t table_desc_valid(uint64_t desc) +{ + return((desc & TABLE_DESC) == TABLE_DESC); +} + +/* + * Func : get_new_table + * Desc : Return the next free XLAT table from ttb buffer + */ +static uint64_t *get_new_table(void) +{ + uint64_t *new; + + if (free_idx >= max_tables) { + printf("ARM64 MMU: No free table\n"); + return NULL; + } + + new = (uint64_t*)((unsigned char *)xlat_addr + free_idx * GRANULE_SIZE); + free_idx++; + + memset(new, 0, GRANULE_SIZE); + + return new; +} + +/* + * Func : get_table_from_desc + * Desc : Get next level table address from table descriptor + */ +static uint64_t *get_table_from_desc(uint64_t desc) +{ + uint64_t *ptr = (uint64_t*)(desc & XLAT_TABLE_MASK); + return ptr; +} + +/* + * Func: get_next_level_table + * Desc: Check if the table entry is a valid descriptor. If not, allocate new + * table, update the entry and return the table addr. If valid, return the addr. + */ +static uint64_t *get_next_level_table(uint64_t *ptr) +{ + uint64_t desc = *ptr; + + if (!table_desc_valid(desc)) { + uint64_t *new_table = get_new_table(); + if (new_table == NULL) + return NULL; + desc = ((uint64_t)new_table) | TABLE_DESC; + *ptr = desc; + } + return get_table_from_desc(desc); +} + +/* + * Func : init_xlat_table + * Desc : Given a base address and size, it identifies the indices within + * different level XLAT tables which map the given base addr. Similar to table + * walk, except that all invalid entries during the walk are updated + * accordingly. On success, it returns the size of the block/page addressed by + * the final table. + */ +static uint64_t init_xlat_table(uint64_t base_addr, + uint64_t size, + uint64_t tag) +{ + uint64_t l1_index = get_index_from_addr(base_addr,1); + uint64_t l2_index = get_index_from_addr(base_addr,2); + uint64_t l3_index = get_index_from_addr(base_addr,3); + uint64_t *table = xlat_addr; + uint64_t desc; + uint64_t attr = get_block_attr(tag); + + /* + * L1 table lookup + * If VA has bits more than 41, lookup starts at L1 + */ + if (l1_index) { + table = get_next_level_table(&table[l1_index]); + if (!table) + return 0; + } + + /* + * L2 table lookup + * If lookup was performed at L1, L2 table addr is obtained from L1 desc + * else, lookup starts at ttbr address + */ + if (!l3_index && (size >= L2_XLAT_SIZE)) { + /* + * If block address is aligned and size is greater than or equal + * to 512MiB i.e. size addressed by each L2 entry, we can + * directly store a block desc + */ + desc = base_addr | BLOCK_DESC | attr; + table[l2_index] = desc; + /* L3 lookup is not required */ + return L2_XLAT_SIZE; + } else { + /* L2 entry stores a table descriptor */ + table = get_next_level_table(&table[l2_index]); + if (!table) + return 0; + } + + /* L3 table lookup */ + desc = base_addr | PAGE_DESC | attr; + table[l3_index] = desc; + return L3_XLAT_SIZE; +} + +/* + * Func : sanity_check + * Desc : Check if the address is aligned and size is atleast the granule size + */ +static uint64_t sanity_check(uint64_t addr, + uint64_t size) +{ + /* Address should be atleast 64 KiB aligned */ + if (addr & GRANULE_SIZE_MASK) + return 1; + + /* Size should be atleast granule size */ + if (size < GRANULE_SIZE) + return 1; + + return 0; +} + +/* + * Func : init_mmap_entry + * Desc : For each mmap entry, this function calls init_xlat_table with the base + * address. Based on size returned from init_xlat_table, base_addr is updated + * and subsequent calls are made for initializing the xlat table until the whole + * region is initialized. + */ +static void init_mmap_entry(struct mmu_memrange *r) +{ + uint64_t base_addr = r->base; + uint64_t size = r->size; + uint64_t tag = r->type; + uint64_t temp_size = size; + + while (temp_size) { + uint64_t ret; + + if (sanity_check(base_addr,temp_size)) { + printf("Libpayload: ARM64 MMU: sanity check failed\n"); + return; + } + + ret = init_xlat_table(base_addr + (size - temp_size), + temp_size, tag); + + if (ret == 0) + return; + + temp_size -= ret; + } +} + +/* + * Func : mmu_init + * Desc : Initialize mmu based on the mmu_memrange passed. ttb_buffer is used as + * the base address for xlat tables. TTB_DEFAULT_SIZE defines the max number of + * tables that can be used + * Assuming that memory 0-2GiB is device memory. + */ +uint64_t mmu_init(struct mmu_ranges *mmu_ranges) +{ + struct mmu_memrange devrange = { 0, 0x80000000, TYPE_DEV_MEM }; + + int i = 0; + + xlat_addr = (uint64_t *)&ttb_buffer; + + memset((void*)xlat_addr, 0, GRANULE_SIZE); + max_tables = (TTB_DEFAULT_SIZE >> GRANULE_SIZE_SHIFT); + free_idx = 1; + + printf("Libpayload ARM64: TTB_BUFFER: 0x%p Max Tables: %d\n", + (void*)xlat_addr, max_tables); + + init_mmap_entry(&devrange); + + for (; i < mmu_ranges->used; i++) { + init_mmap_entry(&mmu_ranges->entries[i]); + } + + printf("Libpayload ARM64: MMU init done\n"); + return 0; +} + +static uint32_t is_mmu_enabled(void) +{ + uint32_t sctlr; + + sctlr = raw_read_sctlr_current(); + + return (sctlr & SCTLR_M); +} + +/* + * Func: mmu_disable + * Desc: Invalidate caches and disable mmu + */ +void mmu_disable(void) +{ + uint32_t sctlr; + + sctlr = raw_read_sctlr_current(); + sctlr &= ~(SCTLR_C | SCTLR_M | SCTLR_I); + + tlbiall_current(); + dcache_clean_invalidate_all(); + + dsb(); + isb(); + + raw_write_sctlr_current(sctlr); + + dcache_clean_invalidate_all(); + dsb(); + isb(); +} + +/* + * Func: mmu_enable + * Desc: Initialize MAIR, TCR, TTBR and enable MMU by setting appropriate bits + * in SCTLR + */ +void mmu_enable(void) +{ + uint32_t sctlr; + + /* Initialize MAIR indices */ + raw_write_mair_current(MAIR_ATTRIBUTES); + + /* Invalidate TLBs */ + tlbiall_current(); + + /* Initialize TCR flags */ + raw_write_tcr_current(TCR_TOSZ | TCR_IRGN0_NM_WBWAC | TCR_ORGN0_NM_WBWAC | + TCR_SH0_IS | TCR_TG0_64KB | TCR_PS_64GB | + TCR_TBI_USED); + + /* Initialize TTBR */ + raw_write_ttbr0_current((uintptr_t)xlat_addr); + + /* Ensure all translation table writes are committed before enabling MMU */ + dsb(); + isb(); + + /* Enable MMU */ + sctlr = raw_read_sctlr_current(); + sctlr |= SCTLR_C | SCTLR_M | SCTLR_I; + raw_write_sctlr_current(sctlr); + + isb(); + + if(is_mmu_enabled()) + printf("ARM64: MMU enable done\n"); + else + printf("ARM64: MMU enable failed\n"); +} + +/* + * Func: mmu_is_dma_range_valid + * Desc: We need to ensure that the dma buffer being allocated doesnt overlap + * with any used memory range. Basically: + * 1. Memory ranges used by the payload (usedmem_ranges) + * 2. Any area that falls below _end symbol in linker script (Kernel needs to be + * loaded in lower areas of memory, So, the payload linker script can have + * kernel memory below _start and _end. Thus, we want to make sure we do not + * step in those areas as well. + * Returns: 1 on success, 0 on error + * ASSUMPTION: All the memory used by payload resides below the program + * proper. If there is any memory used above the _end symbol, then it should be + * marked as used memory in usedmem_ranges during the presysinfo_scan. + */ +static int mmu_is_dma_range_valid(uint64_t dma_base, + uint64_t dma_end) +{ + uint64_t payload_end = (uint64_t)&_end; + uint64_t i = 0; + struct mmu_memrange *r = &usedmem_ranges.entries[0]; + + if ((dma_base <= payload_end) || (dma_end <= payload_end)) + return 0; + + for (; i < usedmem_ranges.used; i++) { + uint64_t start = r[i].base; + uint64_t end = start + r[i].size; + + if (((dma_base >= start) && (dma_base <= end)) || + ((dma_end >= start) && (dma_end <= end))) + return 0; + } + + return 1; +} + +/* + * Func: mmu_add_dma_range + * Desc: Add a memrange for dma operations. This is special because we want to + * initialize this memory as non-cacheable. We have a constraint that the DMA + * buffer should be below 4GiB(32-bit only). So, we lookup a TYPE_NORMAL_MEM + * from the lowest available addresses and align it to page size i.e. 64KiB. + */ +static struct mmu_memrange* mmu_add_dma_range(struct mmu_ranges *mmu_ranges) +{ + int i = 0; + struct mmu_memrange *r = &mmu_ranges->entries[0]; + + for (; i < mmu_ranges->used; i++) { + + if ((r[i].type != TYPE_NORMAL_MEM) || + (r[i].size < DMA_DEFAULT_SIZE) || + (r[i].base >= MIN_64_BIT_ADDR)) + continue; + + uint64_t base_addr; + uint64_t range_end_addr = r[i].base + r[i].size; + uint64_t size; + uint64_t end_addr = range_end_addr; + + /* Make sure we choose only 32-bit address range for DMA */ + if (end_addr > MIN_64_BIT_ADDR) + end_addr = MIN_64_BIT_ADDR; + + /* + * We need to ensure that we do not step over payload regions or + * the coreboot_table + */ + do { + /* + * If end_addr is aligned to GRANULE_SIZE, + * then base_addr will be too. + * (DMA_DEFAULT_SIZE is multiple of GRANULE_SIZE) + */ + assert((DMA_DEFAULT_SIZE % GRANULE_SIZE) == 0); + end_addr = ALIGN_DOWN(end_addr, GRANULE_SIZE); + + base_addr = end_addr - DMA_DEFAULT_SIZE; + size = end_addr - base_addr; + + if (base_addr < r[i].base) + break; + } while (mmu_is_dma_range_valid(base_addr, end_addr) == 0); + + if (base_addr < r[i].base) + continue; + + if (r[i].size == size) { + r[i].type = TYPE_DMA_MEM; + return &r[i]; + } + + if (end_addr != range_end_addr) { + /* Add a new memrange since we split up one + * range crossing the 4GiB boundary or doing an + * ALIGN_DOWN on end_addr. + */ + r[i].size -= (range_end_addr - end_addr); + if (mmu_add_memrange(mmu_ranges, end_addr, + range_end_addr - end_addr, + TYPE_NORMAL_MEM) == NULL) + mmu_error(); + } + + r[i].size -= size; + + r = mmu_add_memrange(mmu_ranges, base_addr, size, TYPE_DMA_MEM); + + if (r == NULL) + mmu_error(); + + return r; + } + + /* Should never reach here if everything went fine */ + printf("ARM64 ERROR: No DMA region allocated\n"); + return NULL; +} + +/* + * Func: mmu_extract_ranges + * Desc: Assumption is that coreboot tables have memranges in sorted + * order. So, if there is an opportunity to combine ranges, we do that as + * well. Memranges are initialized for both CB_MEM_RAM and CB_MEM_TABLE as + * TYPE_NORMAL_MEM. + */ +static void mmu_extract_ranges(struct memrange *cb_ranges, + uint64_t ncb, + struct mmu_ranges *mmu_ranges) +{ + int i = 0; + struct mmu_memrange *prev_range = NULL; + + /* Extract memory ranges to be mapped */ + for (; i < ncb; i++) { + switch (cb_ranges[i].type) { + case CB_MEM_RAM: + case CB_MEM_TABLE: + if (prev_range && (prev_range->base + prev_range->size + == cb_ranges[i].base)) { + prev_range->size += cb_ranges[i].size; + } else { + prev_range = mmu_add_memrange(mmu_ranges, + cb_ranges[i].base, + cb_ranges[i].size, + TYPE_NORMAL_MEM); + if (prev_range == NULL) + mmu_error(); + } + break; + default: + break; + } + } +} + +/* + * Func: mmu_init_ranges + * Desc: Initialize mmu_memranges based on the memranges obtained from coreboot + * tables. Also, initialize dma memrange and xlat_addr for ttb buffer. + */ +struct mmu_memrange *mmu_init_ranges_from_sysinfo(struct memrange *cb_ranges, + uint64_t ncb, + struct mmu_ranges *mmu_ranges) +{ + struct mmu_memrange *dma_range; + + /* Extract ranges from memrange in lib_sysinfo */ + mmu_extract_ranges(cb_ranges, ncb, mmu_ranges); + + /* Get a range for dma */ + dma_range = mmu_add_dma_range(mmu_ranges); + + if (dma_range == NULL) + mmu_error(); + + return dma_range; +} + +/* + * Func: mmu_add_memrange + * Desc: Adds a new memory range + */ +struct mmu_memrange* mmu_add_memrange(struct mmu_ranges *r, uint64_t base, + uint64_t size, uint64_t type) +{ + struct mmu_memrange *curr = NULL; + int i = r->used; + + if (i < ARRAY_SIZE(r->entries)) { + curr = &r->entries[i]; + curr->base = base; + curr->size = size; + curr->type = type; + + r->used = i + 1; + } + + return curr; +} + +/* + * Func: mmu_presysinfo_memory_used + * Desc: Initializes all the memory used for presysinfo page table + * initialization and enabling of MMU. All these ranges are stored in + * usedmem_ranges. usedmem_ranges plays an important role in selecting the dma + * buffer as well since we check the dma buffer range against the used memory + * ranges to prevent any overstepping. + */ +void mmu_presysinfo_memory_used(uint64_t base, uint64_t size) +{ + uint64_t range_base; + + range_base = ALIGN_DOWN(base, GRANULE_SIZE); + + size += (base - range_base); + size = ALIGN_UP(size, GRANULE_SIZE); + + mmu_add_memrange(&usedmem_ranges, range_base, size, TYPE_NORMAL_MEM); +} + +void mmu_presysinfo_enable(void) +{ + mmu_init(&usedmem_ranges); + mmu_enable(); +} |