diff options
Diffstat (limited to 'kernel/dma/swiotlb.c')
| -rw-r--r-- | kernel/dma/swiotlb.c | 1105 |
1 files changed, 1105 insertions, 0 deletions
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c new file mode 100644 index 000000000..ad6333c3f --- /dev/null +++ b/kernel/dma/swiotlb.c @@ -0,0 +1,1105 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Dynamic DMA mapping support. + * + * This implementation is a fallback for platforms that do not support + * I/O TLBs (aka DMA address translation hardware). + * Copyright (C) 2000 Asit Mallick <Asit.K.Mallick@intel.com> + * Copyright (C) 2000 Goutham Rao <goutham.rao@intel.com> + * Copyright (C) 2000, 2003 Hewlett-Packard Co + * David Mosberger-Tang <davidm@hpl.hp.com> + * + * 03/05/07 davidm Switch from PCI-DMA to generic device DMA API. + * 00/12/13 davidm Rename to swiotlb.c and add mark_clean() to avoid + * unnecessary i-cache flushing. + * 04/07/.. ak Better overflow handling. Assorted fixes. + * 05/09/10 linville Add support for syncing ranges, support syncing for + * DMA_BIDIRECTIONAL mappings, miscellaneous cleanup. + * 08/12/11 beckyb Add highmem support + */ + +#define pr_fmt(fmt) "software IO TLB: " fmt + +#include <linux/cache.h> +#include <linux/cc_platform.h> +#include <linux/ctype.h> +#include <linux/debugfs.h> +#include <linux/dma-direct.h> +#include <linux/dma-map-ops.h> +#include <linux/export.h> +#include <linux/gfp.h> +#include <linux/highmem.h> +#include <linux/io.h> +#include <linux/iommu-helper.h> +#include <linux/init.h> +#include <linux/memblock.h> +#include <linux/mm.h> +#include <linux/pfn.h> +#include <linux/scatterlist.h> +#include <linux/set_memory.h> +#include <linux/spinlock.h> +#include <linux/string.h> +#include <linux/swiotlb.h> +#include <linux/types.h> +#ifdef CONFIG_DMA_RESTRICTED_POOL +#include <linux/of.h> +#include <linux/of_fdt.h> +#include <linux/of_reserved_mem.h> +#include <linux/slab.h> +#endif + +#define CREATE_TRACE_POINTS +#include <trace/events/swiotlb.h> + +#define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT)) + +/* + * Minimum IO TLB size to bother booting with. Systems with mainly + * 64bit capable cards will only lightly use the swiotlb. If we can't + * allocate a contiguous 1MB, we're probably in trouble anyway. + */ +#define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT) + +#define INVALID_PHYS_ADDR (~(phys_addr_t)0) + +struct io_tlb_slot { + phys_addr_t orig_addr; + size_t alloc_size; + unsigned int list; +}; + +static bool swiotlb_force_bounce; +static bool swiotlb_force_disable; + +struct io_tlb_mem io_tlb_default_mem; + +phys_addr_t swiotlb_unencrypted_base; + +static unsigned long default_nslabs = IO_TLB_DEFAULT_SIZE >> IO_TLB_SHIFT; +static unsigned long default_nareas; + +/** + * struct io_tlb_area - IO TLB memory area descriptor + * + * This is a single area with a single lock. + * + * @used: The number of used IO TLB block. + * @index: The slot index to start searching in this area for next round. + * @lock: The lock to protect the above data structures in the map and + * unmap calls. + */ +struct io_tlb_area { + unsigned long used; + unsigned int index; + spinlock_t lock; +}; + +/* + * Round up number of slabs to the next power of 2. The last area is going + * be smaller than the rest if default_nslabs is not power of two. + * The number of slot in an area should be a multiple of IO_TLB_SEGSIZE, + * otherwise a segment may span two or more areas. It conflicts with free + * contiguous slots tracking: free slots are treated contiguous no matter + * whether they cross an area boundary. + * + * Return true if default_nslabs is rounded up. + */ +static bool round_up_default_nslabs(void) +{ + if (!default_nareas) + return false; + + if (default_nslabs < IO_TLB_SEGSIZE * default_nareas) + default_nslabs = IO_TLB_SEGSIZE * default_nareas; + else if (is_power_of_2(default_nslabs)) + return false; + default_nslabs = roundup_pow_of_two(default_nslabs); + return true; +} + +/** + * swiotlb_adjust_nareas() - adjust the number of areas and slots + * @nareas: Desired number of areas. Zero is treated as 1. + * + * Adjust the default number of areas in a memory pool. + * The default size of the memory pool may also change to meet minimum area + * size requirements. + */ +static void swiotlb_adjust_nareas(unsigned int nareas) +{ + if (!nareas) + nareas = 1; + else if (!is_power_of_2(nareas)) + nareas = roundup_pow_of_two(nareas); + + default_nareas = nareas; + + pr_info("area num %d.\n", nareas); + if (round_up_default_nslabs()) + pr_info("SWIOTLB bounce buffer size roundup to %luMB", + (default_nslabs << IO_TLB_SHIFT) >> 20); +} + +/** + * limit_nareas() - get the maximum number of areas for a given memory pool size + * @nareas: Desired number of areas. + * @nslots: Total number of slots in the memory pool. + * + * Limit the number of areas to the maximum possible number of areas in + * a memory pool of the given size. + * + * Return: Maximum possible number of areas. + */ +static unsigned int limit_nareas(unsigned int nareas, unsigned long nslots) +{ + if (nslots < nareas * IO_TLB_SEGSIZE) + return nslots / IO_TLB_SEGSIZE; + return nareas; +} + +static int __init +setup_io_tlb_npages(char *str) +{ + if (isdigit(*str)) { + /* avoid tail segment of size < IO_TLB_SEGSIZE */ + default_nslabs = + ALIGN(simple_strtoul(str, &str, 0), IO_TLB_SEGSIZE); + } + if (*str == ',') + ++str; + if (isdigit(*str)) + swiotlb_adjust_nareas(simple_strtoul(str, &str, 0)); + if (*str == ',') + ++str; + if (!strcmp(str, "force")) + swiotlb_force_bounce = true; + else if (!strcmp(str, "noforce")) + swiotlb_force_disable = true; + + return 0; +} +early_param("swiotlb", setup_io_tlb_npages); + +unsigned int swiotlb_max_segment(void) +{ + if (!io_tlb_default_mem.nslabs) + return 0; + return rounddown(io_tlb_default_mem.nslabs << IO_TLB_SHIFT, PAGE_SIZE); +} +EXPORT_SYMBOL_GPL(swiotlb_max_segment); + +unsigned long swiotlb_size_or_default(void) +{ + return default_nslabs << IO_TLB_SHIFT; +} + +void __init swiotlb_adjust_size(unsigned long size) +{ + /* + * If swiotlb parameter has not been specified, give a chance to + * architectures such as those supporting memory encryption to + * adjust/expand SWIOTLB size for their use. + */ + if (default_nslabs != IO_TLB_DEFAULT_SIZE >> IO_TLB_SHIFT) + return; + + size = ALIGN(size, IO_TLB_SIZE); + default_nslabs = ALIGN(size >> IO_TLB_SHIFT, IO_TLB_SEGSIZE); + if (round_up_default_nslabs()) + size = default_nslabs << IO_TLB_SHIFT; + pr_info("SWIOTLB bounce buffer size adjusted to %luMB", size >> 20); +} + +void swiotlb_print_info(void) +{ + struct io_tlb_mem *mem = &io_tlb_default_mem; + + if (!mem->nslabs) { + pr_warn("No low mem\n"); + return; + } + + pr_info("mapped [mem %pa-%pa] (%luMB)\n", &mem->start, &mem->end, + (mem->nslabs << IO_TLB_SHIFT) >> 20); +} + +static inline unsigned long io_tlb_offset(unsigned long val) +{ + return val & (IO_TLB_SEGSIZE - 1); +} + +static inline unsigned long nr_slots(u64 val) +{ + return DIV_ROUND_UP(val, IO_TLB_SIZE); +} + +/* + * Remap swioltb memory in the unencrypted physical address space + * when swiotlb_unencrypted_base is set. (e.g. for Hyper-V AMD SEV-SNP + * Isolation VMs). + */ +#ifdef CONFIG_HAS_IOMEM +static void *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes) +{ + void *vaddr = NULL; + + if (swiotlb_unencrypted_base) { + phys_addr_t paddr = mem->start + swiotlb_unencrypted_base; + + vaddr = memremap(paddr, bytes, MEMREMAP_WB); + if (!vaddr) + pr_err("Failed to map the unencrypted memory %pa size %lx.\n", + &paddr, bytes); + } + + return vaddr; +} +#else +static void *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes) +{ + return NULL; +} +#endif + +/* + * Early SWIOTLB allocation may be too early to allow an architecture to + * perform the desired operations. This function allows the architecture to + * call SWIOTLB when the operations are possible. It needs to be called + * before the SWIOTLB memory is used. + */ +void __init swiotlb_update_mem_attributes(void) +{ + struct io_tlb_mem *mem = &io_tlb_default_mem; + void *vaddr; + unsigned long bytes; + + if (!mem->nslabs || mem->late_alloc) + return; + vaddr = phys_to_virt(mem->start); + bytes = PAGE_ALIGN(mem->nslabs << IO_TLB_SHIFT); + set_memory_decrypted((unsigned long)vaddr, bytes >> PAGE_SHIFT); + + mem->vaddr = swiotlb_mem_remap(mem, bytes); + if (!mem->vaddr) + mem->vaddr = vaddr; +} + +static void swiotlb_init_io_tlb_mem(struct io_tlb_mem *mem, phys_addr_t start, + unsigned long nslabs, unsigned int flags, + bool late_alloc, unsigned int nareas) +{ + void *vaddr = phys_to_virt(start); + unsigned long bytes = nslabs << IO_TLB_SHIFT, i; + + mem->nslabs = nslabs; + mem->start = start; + mem->end = mem->start + bytes; + mem->late_alloc = late_alloc; + mem->nareas = nareas; + mem->area_nslabs = nslabs / mem->nareas; + + mem->force_bounce = swiotlb_force_bounce || (flags & SWIOTLB_FORCE); + + for (i = 0; i < mem->nareas; i++) { + spin_lock_init(&mem->areas[i].lock); + mem->areas[i].index = 0; + mem->areas[i].used = 0; + } + + for (i = 0; i < mem->nslabs; i++) { + mem->slots[i].list = IO_TLB_SEGSIZE - io_tlb_offset(i); + mem->slots[i].orig_addr = INVALID_PHYS_ADDR; + mem->slots[i].alloc_size = 0; + } + + /* + * If swiotlb_unencrypted_base is set, the bounce buffer memory will + * be remapped and cleared in swiotlb_update_mem_attributes. + */ + if (swiotlb_unencrypted_base) + return; + + memset(vaddr, 0, bytes); + mem->vaddr = vaddr; + return; +} + +static void __init *swiotlb_memblock_alloc(unsigned long nslabs, + unsigned int flags, + int (*remap)(void *tlb, unsigned long nslabs)) +{ + size_t bytes = PAGE_ALIGN(nslabs << IO_TLB_SHIFT); + void *tlb; + + /* + * By default allocate the bounce buffer memory from low memory, but + * allow to pick a location everywhere for hypervisors with guest + * memory encryption. + */ + if (flags & SWIOTLB_ANY) + tlb = memblock_alloc(bytes, PAGE_SIZE); + else + tlb = memblock_alloc_low(bytes, PAGE_SIZE); + + if (!tlb) { + pr_warn("%s: Failed to allocate %zu bytes tlb structure\n", + __func__, bytes); + return NULL; + } + + if (remap && remap(tlb, nslabs) < 0) { + memblock_free(tlb, PAGE_ALIGN(bytes)); + pr_warn("%s: Failed to remap %zu bytes\n", __func__, bytes); + return NULL; + } + + return tlb; +} + +/* + * Statically reserve bounce buffer space and initialize bounce buffer data + * structures for the software IO TLB used to implement the DMA API. + */ +void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags, + int (*remap)(void *tlb, unsigned long nslabs)) +{ + struct io_tlb_mem *mem = &io_tlb_default_mem; + unsigned long nslabs; + unsigned int nareas; + size_t alloc_size; + void *tlb; + + if (!addressing_limit && !swiotlb_force_bounce) + return; + if (swiotlb_force_disable) + return; + + if (!default_nareas) + swiotlb_adjust_nareas(num_possible_cpus()); + + nslabs = default_nslabs; + nareas = limit_nareas(default_nareas, nslabs); + while ((tlb = swiotlb_memblock_alloc(nslabs, flags, remap)) == NULL) { + if (nslabs <= IO_TLB_MIN_SLABS) + return; + nslabs = ALIGN(nslabs >> 1, IO_TLB_SEGSIZE); + nareas = limit_nareas(nareas, nslabs); + } + + if (default_nslabs != nslabs) { + pr_info("SWIOTLB bounce buffer size adjusted %lu -> %lu slabs", + default_nslabs, nslabs); + default_nslabs = nslabs; + } + + alloc_size = PAGE_ALIGN(array_size(sizeof(*mem->slots), nslabs)); + mem->slots = memblock_alloc(alloc_size, PAGE_SIZE); + if (!mem->slots) { + pr_warn("%s: Failed to allocate %zu bytes align=0x%lx\n", + __func__, alloc_size, PAGE_SIZE); + return; + } + + mem->areas = memblock_alloc(array_size(sizeof(struct io_tlb_area), + default_nareas), SMP_CACHE_BYTES); + if (!mem->areas) { + pr_warn("%s: Failed to allocate mem->areas.\n", __func__); + return; + } + + swiotlb_init_io_tlb_mem(mem, __pa(tlb), nslabs, flags, false, + default_nareas); + + if (flags & SWIOTLB_VERBOSE) + swiotlb_print_info(); +} + +void __init swiotlb_init(bool addressing_limit, unsigned int flags) +{ + swiotlb_init_remap(addressing_limit, flags, NULL); +} + +/* + * Systems with larger DMA zones (those that don't support ISA) can + * initialize the swiotlb later using the slab allocator if needed. + * This should be just like above, but with some error catching. + */ +int swiotlb_init_late(size_t size, gfp_t gfp_mask, + int (*remap)(void *tlb, unsigned long nslabs)) +{ + struct io_tlb_mem *mem = &io_tlb_default_mem; + unsigned long nslabs = ALIGN(size >> IO_TLB_SHIFT, IO_TLB_SEGSIZE); + unsigned int nareas; + unsigned char *vstart = NULL; + unsigned int order, area_order; + bool retried = false; + int rc = 0; + + if (swiotlb_force_disable) + return 0; + + if (!default_nareas) + swiotlb_adjust_nareas(num_possible_cpus()); + +retry: + order = get_order(nslabs << IO_TLB_SHIFT); + nslabs = SLABS_PER_PAGE << order; + + while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) { + vstart = (void *)__get_free_pages(gfp_mask | __GFP_NOWARN, + order); + if (vstart) + break; + order--; + nslabs = SLABS_PER_PAGE << order; + retried = true; + } + + if (!vstart) + return -ENOMEM; + + if (remap) + rc = remap(vstart, nslabs); + if (rc) { + free_pages((unsigned long)vstart, order); + + nslabs = ALIGN(nslabs >> 1, IO_TLB_SEGSIZE); + if (nslabs < IO_TLB_MIN_SLABS) + return rc; + retried = true; + goto retry; + } + + if (retried) { + pr_warn("only able to allocate %ld MB\n", + (PAGE_SIZE << order) >> 20); + } + + nareas = limit_nareas(default_nareas, nslabs); + area_order = get_order(array_size(sizeof(*mem->areas), nareas)); + mem->areas = (struct io_tlb_area *) + __get_free_pages(GFP_KERNEL | __GFP_ZERO, area_order); + if (!mem->areas) + goto error_area; + + mem->slots = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, + get_order(array_size(sizeof(*mem->slots), nslabs))); + if (!mem->slots) + goto error_slots; + + set_memory_decrypted((unsigned long)vstart, + (nslabs << IO_TLB_SHIFT) >> PAGE_SHIFT); + swiotlb_init_io_tlb_mem(mem, virt_to_phys(vstart), nslabs, 0, true, + nareas); + + swiotlb_print_info(); + return 0; + +error_slots: + free_pages((unsigned long)mem->areas, area_order); +error_area: + free_pages((unsigned long)vstart, order); + return -ENOMEM; +} + +void __init swiotlb_exit(void) +{ + struct io_tlb_mem *mem = &io_tlb_default_mem; + unsigned long tbl_vaddr; + size_t tbl_size, slots_size; + unsigned int area_order; + + if (swiotlb_force_bounce) + return; + + if (!mem->nslabs) + return; + + pr_info("tearing down default memory pool\n"); + tbl_vaddr = (unsigned long)phys_to_virt(mem->start); + tbl_size = PAGE_ALIGN(mem->end - mem->start); + slots_size = PAGE_ALIGN(array_size(sizeof(*mem->slots), mem->nslabs)); + + set_memory_encrypted(tbl_vaddr, tbl_size >> PAGE_SHIFT); + if (mem->late_alloc) { + area_order = get_order(array_size(sizeof(*mem->areas), + mem->nareas)); + free_pages((unsigned long)mem->areas, area_order); + free_pages(tbl_vaddr, get_order(tbl_size)); + free_pages((unsigned long)mem->slots, get_order(slots_size)); + } else { + memblock_free_late(__pa(mem->areas), + array_size(sizeof(*mem->areas), mem->nareas)); + memblock_free_late(mem->start, tbl_size); + memblock_free_late(__pa(mem->slots), slots_size); + } + + memset(mem, 0, sizeof(*mem)); +} + +/* + * Return the offset into a iotlb slot required to keep the device happy. + */ +static unsigned int swiotlb_align_offset(struct device *dev, u64 addr) +{ + return addr & dma_get_min_align_mask(dev) & (IO_TLB_SIZE - 1); +} + +/* + * Bounce: copy the swiotlb buffer from or back to the original dma location + */ +static void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t size, + enum dma_data_direction dir) +{ + struct io_tlb_mem *mem = dev->dma_io_tlb_mem; + int index = (tlb_addr - mem->start) >> IO_TLB_SHIFT; + phys_addr_t orig_addr = mem->slots[index].orig_addr; + size_t alloc_size = mem->slots[index].alloc_size; + unsigned long pfn = PFN_DOWN(orig_addr); + unsigned char *vaddr = mem->vaddr + tlb_addr - mem->start; + unsigned int tlb_offset, orig_addr_offset; + + if (orig_addr == INVALID_PHYS_ADDR) + return; + + tlb_offset = tlb_addr & (IO_TLB_SIZE - 1); + orig_addr_offset = swiotlb_align_offset(dev, orig_addr); + if (tlb_offset < orig_addr_offset) { + dev_WARN_ONCE(dev, 1, + "Access before mapping start detected. orig offset %u, requested offset %u.\n", + orig_addr_offset, tlb_offset); + return; + } + + tlb_offset -= orig_addr_offset; + if (tlb_offset > alloc_size) { + dev_WARN_ONCE(dev, 1, + "Buffer overflow detected. Allocation size: %zu. Mapping size: %zu+%u.\n", + alloc_size, size, tlb_offset); + return; + } + + orig_addr += tlb_offset; + alloc_size -= tlb_offset; + + if (size > alloc_size) { + dev_WARN_ONCE(dev, 1, + "Buffer overflow detected. Allocation size: %zu. Mapping size: %zu.\n", + alloc_size, size); + size = alloc_size; + } + + if (PageHighMem(pfn_to_page(pfn))) { + unsigned int offset = orig_addr & ~PAGE_MASK; + struct page *page; + unsigned int sz = 0; + unsigned long flags; + + while (size) { + sz = min_t(size_t, PAGE_SIZE - offset, size); + + local_irq_save(flags); + page = pfn_to_page(pfn); + if (dir == DMA_TO_DEVICE) + memcpy_from_page(vaddr, page, offset, sz); + else + memcpy_to_page(page, offset, vaddr, sz); + local_irq_restore(flags); + + size -= sz; + pfn++; + vaddr += sz; + offset = 0; + } + } else if (dir == DMA_TO_DEVICE) { + memcpy(vaddr, phys_to_virt(orig_addr), size); + } else { + memcpy(phys_to_virt(orig_addr), vaddr, size); + } +} + +static inline phys_addr_t slot_addr(phys_addr_t start, phys_addr_t idx) +{ + return start + (idx << IO_TLB_SHIFT); +} + +/* + * Carefully handle integer overflow which can occur when boundary_mask == ~0UL. + */ +static inline unsigned long get_max_slots(unsigned long boundary_mask) +{ + if (boundary_mask == ~0UL) + return 1UL << (BITS_PER_LONG - IO_TLB_SHIFT); + return nr_slots(boundary_mask + 1); +} + +static unsigned int wrap_area_index(struct io_tlb_mem *mem, unsigned int index) +{ + if (index >= mem->area_nslabs) + return 0; + return index; +} + +/* + * Find a suitable number of IO TLB entries size that will fit this request and + * allocate a buffer from that IO TLB pool. + */ +static int swiotlb_do_find_slots(struct device *dev, int area_index, + phys_addr_t orig_addr, size_t alloc_size, + unsigned int alloc_align_mask) +{ + struct io_tlb_mem *mem = dev->dma_io_tlb_mem; + struct io_tlb_area *area = mem->areas + area_index; + unsigned long boundary_mask = dma_get_seg_boundary(dev); + dma_addr_t tbl_dma_addr = + phys_to_dma_unencrypted(dev, mem->start) & boundary_mask; + unsigned long max_slots = get_max_slots(boundary_mask); + unsigned int iotlb_align_mask = + dma_get_min_align_mask(dev) & ~(IO_TLB_SIZE - 1); + unsigned int nslots = nr_slots(alloc_size), stride; + unsigned int index, wrap, count = 0, i; + unsigned int offset = swiotlb_align_offset(dev, orig_addr); + unsigned long flags; + unsigned int slot_base; + unsigned int slot_index; + + BUG_ON(!nslots); + BUG_ON(area_index >= mem->nareas); + + /* + * For mappings with an alignment requirement don't bother looping to + * unaligned slots once we found an aligned one. For allocations of + * PAGE_SIZE or larger only look for page aligned allocations. + */ + stride = (iotlb_align_mask >> IO_TLB_SHIFT) + 1; + if (alloc_size >= PAGE_SIZE) + stride = max(stride, stride << (PAGE_SHIFT - IO_TLB_SHIFT)); + stride = max(stride, (alloc_align_mask >> IO_TLB_SHIFT) + 1); + + spin_lock_irqsave(&area->lock, flags); + if (unlikely(nslots > mem->area_nslabs - area->used)) + goto not_found; + + slot_base = area_index * mem->area_nslabs; + index = wrap = wrap_area_index(mem, ALIGN(area->index, stride)); + + do { + slot_index = slot_base + index; + + if (orig_addr && + (slot_addr(tbl_dma_addr, slot_index) & + iotlb_align_mask) != (orig_addr & iotlb_align_mask)) { + index = wrap_area_index(mem, index + 1); + continue; + } + + /* + * If we find a slot that indicates we have 'nslots' number of + * contiguous buffers, we allocate the buffers from that slot + * and mark the entries as '0' indicating unavailable. + */ + if (!iommu_is_span_boundary(slot_index, nslots, + nr_slots(tbl_dma_addr), + max_slots)) { + if (mem->slots[slot_index].list >= nslots) + goto found; + } + index = wrap_area_index(mem, index + stride); + } while (index != wrap); + +not_found: + spin_unlock_irqrestore(&area->lock, flags); + return -1; + +found: + for (i = slot_index; i < slot_index + nslots; i++) { + mem->slots[i].list = 0; + mem->slots[i].alloc_size = alloc_size - (offset + + ((i - slot_index) << IO_TLB_SHIFT)); + } + for (i = slot_index - 1; + io_tlb_offset(i) != IO_TLB_SEGSIZE - 1 && + mem->slots[i].list; i--) + mem->slots[i].list = ++count; + + /* + * Update the indices to avoid searching in the next round. + */ + if (index + nslots < mem->area_nslabs) + area->index = index + nslots; + else + area->index = 0; + area->used += nslots; + spin_unlock_irqrestore(&area->lock, flags); + return slot_index; +} + +static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr, + size_t alloc_size, unsigned int alloc_align_mask) +{ + struct io_tlb_mem *mem = dev->dma_io_tlb_mem; + int start = raw_smp_processor_id() & (mem->nareas - 1); + int i = start, index; + + do { + index = swiotlb_do_find_slots(dev, i, orig_addr, alloc_size, + alloc_align_mask); + if (index >= 0) + return index; + if (++i >= mem->nareas) + i = 0; + } while (i != start); + + return -1; +} + +static unsigned long mem_used(struct io_tlb_mem *mem) +{ + int i; + unsigned long used = 0; + + for (i = 0; i < mem->nareas; i++) + used += mem->areas[i].used; + return used; +} + +phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr, + size_t mapping_size, size_t alloc_size, + unsigned int alloc_align_mask, enum dma_data_direction dir, + unsigned long attrs) +{ + struct io_tlb_mem *mem = dev->dma_io_tlb_mem; + unsigned int offset = swiotlb_align_offset(dev, orig_addr); + unsigned int i; + int index; + phys_addr_t tlb_addr; + + if (!mem || !mem->nslabs) { + dev_warn_ratelimited(dev, + "Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer"); + return (phys_addr_t)DMA_MAPPING_ERROR; + } + + if (cc_platform_has(CC_ATTR_MEM_ENCRYPT)) + pr_warn_once("Memory encryption is active and system is using DMA bounce buffers\n"); + + if (mapping_size > alloc_size) { + dev_warn_once(dev, "Invalid sizes (mapping: %zd bytes, alloc: %zd bytes)", + mapping_size, alloc_size); + return (phys_addr_t)DMA_MAPPING_ERROR; + } + + index = swiotlb_find_slots(dev, orig_addr, + alloc_size + offset, alloc_align_mask); + if (index == -1) { + if (!(attrs & DMA_ATTR_NO_WARN)) + dev_warn_ratelimited(dev, + "swiotlb buffer is full (sz: %zd bytes), total %lu (slots), used %lu (slots)\n", + alloc_size, mem->nslabs, mem_used(mem)); + return (phys_addr_t)DMA_MAPPING_ERROR; + } + + /* + * Save away the mapping from the original address to the DMA address. + * This is needed when we sync the memory. Then we sync the buffer if + * needed. + */ + for (i = 0; i < nr_slots(alloc_size + offset); i++) + mem->slots[index + i].orig_addr = slot_addr(orig_addr, i); + tlb_addr = slot_addr(mem->start, index) + offset; + /* + * When dir == DMA_FROM_DEVICE we could omit the copy from the orig + * to the tlb buffer, if we knew for sure the device will + * overwrite the entire current content. But we don't. Thus + * unconditional bounce may prevent leaking swiotlb content (i.e. + * kernel memory) to user-space. + */ + swiotlb_bounce(dev, tlb_addr, mapping_size, DMA_TO_DEVICE); + return tlb_addr; +} + +static void swiotlb_release_slots(struct device *dev, phys_addr_t tlb_addr) +{ + struct io_tlb_mem *mem = dev->dma_io_tlb_mem; + unsigned long flags; + unsigned int offset = swiotlb_align_offset(dev, tlb_addr); + int index = (tlb_addr - offset - mem->start) >> IO_TLB_SHIFT; + int nslots = nr_slots(mem->slots[index].alloc_size + offset); + int aindex = index / mem->area_nslabs; + struct io_tlb_area *area = &mem->areas[aindex]; + int count, i; + + /* + * Return the buffer to the free list by setting the corresponding + * entries to indicate the number of contiguous entries available. + * While returning the entries to the free list, we merge the entries + * with slots below and above the pool being returned. + */ + BUG_ON(aindex >= mem->nareas); + + spin_lock_irqsave(&area->lock, flags); + if (index + nslots < ALIGN(index + 1, IO_TLB_SEGSIZE)) + count = mem->slots[index + nslots].list; + else + count = 0; + + /* + * Step 1: return the slots to the free list, merging the slots with + * superceeding slots + */ + for (i = index + nslots - 1; i >= index; i--) { + mem->slots[i].list = ++count; + mem->slots[i].orig_addr = INVALID_PHYS_ADDR; + mem->slots[i].alloc_size = 0; + } + + /* + * Step 2: merge the returned slots with the preceding slots, if + * available (non zero) + */ + for (i = index - 1; + io_tlb_offset(i) != IO_TLB_SEGSIZE - 1 && mem->slots[i].list; + i--) + mem->slots[i].list = ++count; + area->used -= nslots; + spin_unlock_irqrestore(&area->lock, flags); +} + +/* + * tlb_addr is the physical address of the bounce buffer to unmap. + */ +void swiotlb_tbl_unmap_single(struct device *dev, phys_addr_t tlb_addr, + size_t mapping_size, enum dma_data_direction dir, + unsigned long attrs) +{ + /* + * First, sync the memory before unmapping the entry + */ + if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) && + (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL)) + swiotlb_bounce(dev, tlb_addr, mapping_size, DMA_FROM_DEVICE); + + swiotlb_release_slots(dev, tlb_addr); +} + +void swiotlb_sync_single_for_device(struct device *dev, phys_addr_t tlb_addr, + size_t size, enum dma_data_direction dir) +{ + if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL) + swiotlb_bounce(dev, tlb_addr, size, DMA_TO_DEVICE); + else + BUG_ON(dir != DMA_FROM_DEVICE); +} + +void swiotlb_sync_single_for_cpu(struct device *dev, phys_addr_t tlb_addr, + size_t size, enum dma_data_direction dir) +{ + if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL) + swiotlb_bounce(dev, tlb_addr, size, DMA_FROM_DEVICE); + else + BUG_ON(dir != DMA_TO_DEVICE); +} + +/* + * Create a swiotlb mapping for the buffer at @paddr, and in case of DMAing + * to the device copy the data into it as well. + */ +dma_addr_t swiotlb_map(struct device *dev, phys_addr_t paddr, size_t size, + enum dma_data_direction dir, unsigned long attrs) +{ + phys_addr_t swiotlb_addr; + dma_addr_t dma_addr; + + trace_swiotlb_bounced(dev, phys_to_dma(dev, paddr), size); + + swiotlb_addr = swiotlb_tbl_map_single(dev, paddr, size, size, 0, dir, + attrs); + if (swiotlb_addr == (phys_addr_t)DMA_MAPPING_ERROR) + return DMA_MAPPING_ERROR; + + /* Ensure that the address returned is DMA'ble */ + dma_addr = phys_to_dma_unencrypted(dev, swiotlb_addr); + if (unlikely(!dma_capable(dev, dma_addr, size, true))) { + swiotlb_tbl_unmap_single(dev, swiotlb_addr, size, dir, + attrs | DMA_ATTR_SKIP_CPU_SYNC); + dev_WARN_ONCE(dev, 1, + "swiotlb addr %pad+%zu overflow (mask %llx, bus limit %llx).\n", + &dma_addr, size, *dev->dma_mask, dev->bus_dma_limit); + return DMA_MAPPING_ERROR; + } + + if (!dev_is_dma_coherent(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) + arch_sync_dma_for_device(swiotlb_addr, size, dir); + return dma_addr; +} + +size_t swiotlb_max_mapping_size(struct device *dev) +{ + int min_align_mask = dma_get_min_align_mask(dev); + int min_align = 0; + + /* + * swiotlb_find_slots() skips slots according to + * min align mask. This affects max mapping size. + * Take it into acount here. + */ + if (min_align_mask) + min_align = roundup(min_align_mask, IO_TLB_SIZE); + + return ((size_t)IO_TLB_SIZE) * IO_TLB_SEGSIZE - min_align; +} + +bool is_swiotlb_active(struct device *dev) +{ + struct io_tlb_mem *mem = dev->dma_io_tlb_mem; + + return mem && mem->nslabs; +} +EXPORT_SYMBOL_GPL(is_swiotlb_active); + +static int io_tlb_used_get(void *data, u64 *val) +{ + struct io_tlb_mem *mem = data; + + *val = mem_used(mem); + return 0; +} +DEFINE_DEBUGFS_ATTRIBUTE(fops_io_tlb_used, io_tlb_used_get, NULL, "%llu\n"); + +static void swiotlb_create_debugfs_files(struct io_tlb_mem *mem, + const char *dirname) +{ + mem->debugfs = debugfs_create_dir(dirname, io_tlb_default_mem.debugfs); + if (!mem->nslabs) + return; + + debugfs_create_ulong("io_tlb_nslabs", 0400, mem->debugfs, &mem->nslabs); + debugfs_create_file("io_tlb_used", 0400, mem->debugfs, mem, + &fops_io_tlb_used); +} + +static int __init __maybe_unused swiotlb_create_default_debugfs(void) +{ + swiotlb_create_debugfs_files(&io_tlb_default_mem, "swiotlb"); + return 0; +} + +#ifdef CONFIG_DEBUG_FS +late_initcall(swiotlb_create_default_debugfs); +#endif + +#ifdef CONFIG_DMA_RESTRICTED_POOL + +struct page *swiotlb_alloc(struct device *dev, size_t size) +{ + struct io_tlb_mem *mem = dev->dma_io_tlb_mem; + phys_addr_t tlb_addr; + int index; + + if (!mem) + return NULL; + + index = swiotlb_find_slots(dev, 0, size, 0); + if (index == -1) + return NULL; + + tlb_addr = slot_addr(mem->start, index); + + return pfn_to_page(PFN_DOWN(tlb_addr)); +} + +bool swiotlb_free(struct device *dev, struct page *page, size_t size) +{ + phys_addr_t tlb_addr = page_to_phys(page); + + if (!is_swiotlb_buffer(dev, tlb_addr)) + return false; + + swiotlb_release_slots(dev, tlb_addr); + + return true; +} + +static int rmem_swiotlb_device_init(struct reserved_mem *rmem, + struct device *dev) +{ + struct io_tlb_mem *mem = rmem->priv; + unsigned long nslabs = rmem->size >> IO_TLB_SHIFT; + + /* Set Per-device io tlb area to one */ + unsigned int nareas = 1; + + if (PageHighMem(pfn_to_page(PHYS_PFN(rmem->base)))) { + dev_err(dev, "Restricted DMA pool must be accessible within the linear mapping."); + return -EINVAL; + } + + /* + * Since multiple devices can share the same pool, the private data, + * io_tlb_mem struct, will be initialized by the first device attached + * to it. + */ + if (!mem) { + mem = kzalloc(sizeof(*mem), GFP_KERNEL); + if (!mem) + return -ENOMEM; + + mem->slots = kcalloc(nslabs, sizeof(*mem->slots), GFP_KERNEL); + if (!mem->slots) { + kfree(mem); + return -ENOMEM; + } + + mem->areas = kcalloc(nareas, sizeof(*mem->areas), + GFP_KERNEL); + if (!mem->areas) { + kfree(mem->slots); + kfree(mem); + return -ENOMEM; + } + + set_memory_decrypted((unsigned long)phys_to_virt(rmem->base), + rmem->size >> PAGE_SHIFT); + swiotlb_init_io_tlb_mem(mem, rmem->base, nslabs, SWIOTLB_FORCE, + false, nareas); + mem->for_alloc = true; + + rmem->priv = mem; + + swiotlb_create_debugfs_files(mem, rmem->name); + } + + dev->dma_io_tlb_mem = mem; + + return 0; +} + +static void rmem_swiotlb_device_release(struct reserved_mem *rmem, + struct device *dev) +{ + dev->dma_io_tlb_mem = &io_tlb_default_mem; +} + +static const struct reserved_mem_ops rmem_swiotlb_ops = { + .device_init = rmem_swiotlb_device_init, + .device_release = rmem_swiotlb_device_release, +}; + +static int __init rmem_swiotlb_setup(struct reserved_mem *rmem) +{ + unsigned long node = rmem->fdt_node; + + if (of_get_flat_dt_prop(node, "reusable", NULL) || + of_get_flat_dt_prop(node, "linux,cma-default", NULL) || + of_get_flat_dt_prop(node, "linux,dma-default", NULL) || + of_get_flat_dt_prop(node, "no-map", NULL)) + return -EINVAL; + + rmem->ops = &rmem_swiotlb_ops; + pr_info("Reserved memory: created restricted DMA pool at %pa, size %ld MiB\n", + &rmem->base, (unsigned long)rmem->size / SZ_1M); + return 0; +} + +RESERVEDMEM_OF_DECLARE(dma, "restricted-dma-pool", rmem_swiotlb_setup); +#endif /* CONFIG_DMA_RESTRICTED_POOL */ |