litmus-rt.git - The LITMUS^RT kernel.

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Diffstat (limited to 'net/ipv4/tcp_input.c')

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/* * 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 */ #include <linux/cache.h> #include <linux/dma-mapping.h> #include <linux/mm.h> #include <linux/export.h> #include <linux/spinlock.h> #include <linux/string.h> #include <linux/swiotlb.h> #include <linux/pfn.h> #include <linux/types.h> #include <linux/ctype.h> #include <linux/highmem.h> #include <linux/gfp.h> #include <asm/io.h> #include <asm/dma.h> #include <asm/scatterlist.h> #include <linux/init.h> #include <linux/bootmem.h> #include <linux/iommu-helper.h> #define OFFSET(val,align) ((unsigned long) \ ( (val) & ( (align) - 1))) #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) int swiotlb_force; /* * Used to do a quick range check in swiotlb_tbl_unmap_single and * swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this * API. */ static phys_addr_t io_tlb_start, io_tlb_end; /* * The number of IO TLB blocks (in groups of 64) between io_tlb_start and * io_tlb_end. This is command line adjustable via setup_io_tlb_npages. */ static unsigned long io_tlb_nslabs; /* * When the IOMMU overflows we return a fallback buffer. This sets the size. */ static unsigned long io_tlb_overflow = 32*1024; static phys_addr_t io_tlb_overflow_buffer; /* * This is a free list describing the number of free entries available from * each index */ static unsigned int *io_tlb_list; static unsigned int io_tlb_index; /* * We need to save away the original address corresponding to a mapped entry * for the sync operations. */ static phys_addr_t *io_tlb_orig_addr; /* * Protect the above data structures in the map and unmap calls */ static DEFINE_SPINLOCK(io_tlb_lock); static int late_alloc; static int __init setup_io_tlb_npages(char *str) { if (isdigit(*str)) { io_tlb_nslabs = simple_strtoul(str, &str, 0); /* avoid tail segment of size < IO_TLB_SEGSIZE */ io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE); } if (*str == ',') ++str; if (!strcmp(str, "force")) swiotlb_force = 1; return 0; } early_param("swiotlb", setup_io_tlb_npages); /* make io_tlb_overflow tunable too? */ unsigned long swiotlb_nr_tbl(void) { return io_tlb_nslabs; } EXPORT_SYMBOL_GPL(swiotlb_nr_tbl); /* default to 64MB */ #define IO_TLB_DEFAULT_SIZE (64UL<<20) unsigned long swiotlb_size_or_default(void) { unsigned long size; size = io_tlb_nslabs << IO_TLB_SHIFT; return size ? size : (IO_TLB_DEFAULT_SIZE); } /* Note that this doesn't work with highmem page */ static dma_addr_t swiotlb_virt_to_bus(struct device *hwdev, volatile void *address) { return phys_to_dma(hwdev, virt_to_phys(address)); } static bool no_iotlb_memory; void swiotlb_print_info(void) { unsigned long bytes = io_tlb_nslabs << IO_TLB_SHIFT; unsigned char *vstart, *vend; if (no_iotlb_memory) { pr_warn("software IO TLB: No low mem\n"); return; } vstart = phys_to_virt(io_tlb_start); vend = phys_to_virt(io_tlb_end); printk(KERN_INFO "software IO TLB [mem %#010llx-%#010llx] (%luMB) mapped at [%p-%p]\n", (unsigned long long)io_tlb_start, (unsigned long long)io_tlb_end, bytes >> 20, vstart, vend - 1); } int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose) { void *v_overflow_buffer; unsigned long i, bytes; bytes = nslabs << IO_TLB_SHIFT; io_tlb_nslabs = nslabs; io_tlb_start = __pa(tlb); io_tlb_end = io_tlb_start + bytes; /* * Get the overflow emergency buffer */ v_overflow_buffer = alloc_bootmem_low_pages_nopanic( PAGE_ALIGN(io_tlb_overflow)); if (!v_overflow_buffer) return -ENOMEM; io_tlb_overflow_buffer = __pa(v_overflow_buffer); /* * Allocate and initialize the free list array. This array is used * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE * between io_tlb_start and io_tlb_end. */ io_tlb_list = alloc_bootmem_pages(PAGE_ALIGN(io_tlb_nslabs * sizeof(int))); for (i = 0; i < io_tlb_nslabs; i++) io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE); io_tlb_index = 0; io_tlb_orig_addr = alloc_bootmem_pages(PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t))); if (verbose) swiotlb_print_info(); return 0; } /* * 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(int verbose) { size_t default_size = IO_TLB_DEFAULT_SIZE; unsigned char *vstart; unsigned long bytes; if (!io_tlb_nslabs) { io_tlb_nslabs = (default_size >> IO_TLB_SHIFT); io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE); } bytes = io_tlb_nslabs << IO_TLB_SHIFT; /* Get IO TLB memory from the low pages */ vstart = alloc_bootmem_low_pages_nopanic(PAGE_ALIGN(bytes)); if (vstart && !swiotlb_init_with_tbl(vstart, io_tlb_nslabs, verbose)) return; if (io_tlb_start) free_bootmem(io_tlb_start, PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT)); pr_warn("Cannot allocate SWIOTLB buffer"); no_iotlb_memory = true; } /* * 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_late_init_with_default_size(size_t default_size) { unsigned long bytes, req_nslabs = io_tlb_nslabs; unsigned char *vstart = NULL; unsigned int order; int rc = 0; if (!io_tlb_nslabs) { io_tlb_nslabs = (default_size >> IO_TLB_SHIFT); io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE); } /* * Get IO TLB memory from the low pages */ order = get_order(io_tlb_nslabs << IO_TLB_SHIFT); io_tlb_nslabs = SLABS_PER_PAGE << order; bytes = io_tlb_nslabs << IO_TLB_SHIFT; while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) { vstart = (void *)__get_free_pages(GFP_DMA | __GFP_NOWARN, order); if (vstart) break; order--; } if (!vstart) { io_tlb_nslabs = req_nslabs; return -ENOMEM; } if (order != get_order(bytes)) { printk(KERN_WARNING "Warning: only able to allocate %ld MB " "for software IO TLB\n", (PAGE_SIZE << order) >> 20); io_tlb_nslabs = SLABS_PER_PAGE << order; } rc = swiotlb_late_init_with_tbl(vstart, io_tlb_nslabs); if (rc) free_pages((unsigned long)vstart, order); return rc; } int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs) { unsigned long i, bytes; unsigned char *v_overflow_buffer; bytes = nslabs << IO_TLB_SHIFT; io_tlb_nslabs = nslabs; io_tlb_start = virt_to_phys(tlb); io_tlb_end = io_tlb_start + bytes; memset(tlb, 0, bytes); /* * Get the overflow emergency buffer */ v_overflow_buffer = (void *)__get_free_pages(GFP_DMA, get_order(io_tlb_overflow)); if (!v_overflow_buffer) goto cleanup2; io_tlb_overflow_buffer = virt_to_phys(v_overflow_buffer); /* * Allocate and initialize the free list array. This array is used * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE * between io_tlb_start and io_tlb_end. */ io_tlb_list = (unsigned int *)__get_free_pages(GFP_KERNEL, get_order(io_tlb_nslabs * sizeof(int))); if (!io_tlb_list) goto cleanup3; for (i = 0; i < io_tlb_nslabs; i++) io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE); io_tlb_index = 0; io_tlb_orig_addr = (phys_addr_t *) __get_free_pages(GFP_KERNEL, get_order(io_tlb_nslabs * sizeof(phys_addr_t))); if (!io_tlb_orig_addr) goto cleanup4; memset(io_tlb_orig_addr, 0, io_tlb_nslabs * sizeof(phys_addr_t)); swiotlb_print_info(); late_alloc = 1; return 0; cleanup4: free_pages((unsigned long)io_tlb_list, get_order(io_tlb_nslabs * sizeof(int))); io_tlb_list = NULL; cleanup3: free_pages((unsigned long)v_overflow_buffer, get_order(io_tlb_overflow)); io_tlb_overflow_buffer = 0; cleanup2: io_tlb_end = 0; io_tlb_start = 0; io_tlb_nslabs = 0; return -ENOMEM; } void __init swiotlb_free(void) { if (!io_tlb_orig_addr) return; if (late_alloc) { free_pages((unsigned long)phys_to_virt(io_tlb_overflow_buffer), get_order(io_tlb_overflow)); free_pages((unsigned long)io_tlb_orig_addr, get_order(io_tlb_nslabs * sizeof(phys_addr_t))); free_pages((unsigned long)io_tlb_list, get_order(io_tlb_nslabs * sizeof(int))); free_pages((unsigned long)phys_to_virt(io_tlb_start), get_order(io_tlb_nslabs << IO_TLB_SHIFT)); } else { free_bootmem_late(io_tlb_overflow_buffer, PAGE_ALIGN(io_tlb_overflow)); free_bootmem_late(__pa(io_tlb_orig_addr), PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t))); free_bootmem_late(__pa(io_tlb_list), PAGE_ALIGN(io_tlb_nslabs * sizeof(int))); free_bootmem_late(io_tlb_start, PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT)); } io_tlb_nslabs = 0; } static int is_swiotlb_buffer(phys_addr_t paddr) { return paddr >= io_tlb_start && paddr < io_tlb_end; } /* * Bounce: copy the swiotlb buffer back to the original dma location */ static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr, size_t size, enum dma_data_direction dir) { unsigned long pfn = PFN_DOWN(orig_addr); unsigned char *vaddr = phys_to_virt(tlb_addr); if (PageHighMem(pfn_to_page(pfn))) { /* The buffer does not have a mapping. Map it in and copy */ unsigned int offset = orig_addr & ~PAGE_MASK; char *buffer; unsigned int sz = 0; unsigned long flags; while (size) { sz = min_t(size_t, PAGE_SIZE - offset, size); local_irq_save(flags); buffer = kmap_atomic(pfn_to_page(pfn)); if (dir == DMA_TO_DEVICE) memcpy(vaddr, buffer + offset, sz); else memcpy(buffer + offset, vaddr, sz); kunmap_atomic(buffer); 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); } } phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, dma_addr_t tbl_dma_addr, phys_addr_t orig_addr, size_t size, enum dma_data_direction dir) { unsigned long flags; phys_addr_t tlb_addr; unsigned int nslots, stride, index, wrap; int i; unsigned long mask; unsigned long offset_slots; unsigned long max_slots; if (no_iotlb_memory) panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer"); mask = dma_get_seg_boundary(hwdev); tbl_dma_addr &= mask; offset_slots = ALIGN(tbl_dma_addr, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT; /* * Carefully handle integer overflow which can occur when mask == ~0UL. */ max_slots = mask + 1 ? ALIGN(mask + 1, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT : 1UL << (BITS_PER_LONG - IO_TLB_SHIFT); /* * For mappings greater than a page, we limit the stride (and * hence alignment) to a page size. */ nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT; if (size > PAGE_SIZE) stride = (1 << (PAGE_SHIFT - IO_TLB_SHIFT)); else stride = 1; BUG_ON(!nslots); /* * Find suitable number of IO TLB entries size that will fit this * request and allocate a buffer from that IO TLB pool. */ spin_lock_irqsave(&io_tlb_lock, flags); index = ALIGN(io_tlb_index, stride); if (index >= io_tlb_nslabs) index = 0; wrap = index; do { while (iommu_is_span_boundary(index, nslots, offset_slots, max_slots)) { index += stride; if (index >= io_tlb_nslabs) index = 0; if (index == wrap) goto not_found; } /* * 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 (io_tlb_list[index] >= nslots) { int count = 0; for (i = index; i < (int) (index + nslots); i++) io_tlb_list[i] = 0; for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE - 1) && io_tlb_list[i]; i--) io_tlb_list[i] = ++count; tlb_addr = io_tlb_start + (index << IO_TLB_SHIFT); /* * Update the indices to avoid searching in the next * round. */ io_tlb_index = ((index + nslots) < io_tlb_nslabs ? (index + nslots) : 0); goto found; } index += stride; if (index >= io_tlb_nslabs) index = 0; } while (index != wrap); not_found: spin_unlock_irqrestore(&io_tlb_lock, flags); return SWIOTLB_MAP_ERROR; found: spin_unlock_irqrestore(&io_tlb_lock, flags); /* * 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 < nslots; i++) io_tlb_orig_addr[index+i] = orig_addr + (i << IO_TLB_SHIFT); if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL) swiotlb_bounce(orig_addr, tlb_addr, size, DMA_TO_DEVICE); return tlb_addr; } EXPORT_SYMBOL_GPL(swiotlb_tbl_map_single); /* * Allocates bounce buffer and returns its kernel virtual address. */ phys_addr_t map_single(struct device *hwdev, phys_addr_t phys, size_t size, enum dma_data_direction dir) { dma_addr_t start_dma_addr = phys_to_dma(hwdev, io_tlb_start); return swiotlb_tbl_map_single(hwdev, start_dma_addr, phys, size, dir); } /* * dma_addr is the kernel virtual address of the bounce buffer to unmap. */ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr, size_t size, enum dma_data_direction dir) { unsigned long flags; int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT; int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT; phys_addr_t orig_addr = io_tlb_orig_addr[index]; /* * First, sync the memory before unmapping the entry */ if (orig_addr && ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL))) swiotlb_bounce(orig_addr, tlb_addr, size, DMA_FROM_DEVICE); /* * 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. */ spin_lock_irqsave(&io_tlb_lock, flags); { count = ((index + nslots) < ALIGN(index + 1, IO_TLB_SEGSIZE) ? io_tlb_list[index + nslots] : 0); /* * Step 1: return the slots to the free list, merging the * slots with superceeding slots */ for (i = index + nslots - 1; i >= index; i--) io_tlb_list[i] = ++count; /* * Step 2: merge the returned slots with the preceding slots, * if available (non zero) */ for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE -1) && io_tlb_list[i]; i--)


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