/* * Copyright (c) 2006 Oracle. All rights reserved. * * This software is available to you under a choice of one of two * licenses. You may choose to be licensed under the terms of the GNU * General Public License (GPL) Version 2, available from the file * COPYING in the main directory of this source tree, or the * OpenIB.org BSD license below: * * Redistribution and use in source and binary forms, with or * without modification, are permitted provided that the following * conditions are met: * * - Redistributions of source code must retain the above * copyright notice, this list of conditions and the following * disclaimer. * * - 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. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. * */ #include #include #include #include #include "rds.h" struct rds_page_remainder { struct page *r_page; unsigned long r_offset; }; static DEFINE_PER_CPU_SHARED_ALIGNED(struct rds_page_remainder, rds_page_remainders); /* * returns 0 on success or -errno on failure. * * We don't have to worry about flush_dcache_page() as this only works * with private pages. If, say, we were to do directed receive to pinned * user pages we'd have to worry more about cache coherence. (Though * the flush_dcache_page() in get_user_pages() would probably be enough). */ int rds_page_copy_user(struct page *page, unsigned long offset, void __user *ptr, unsigned long bytes, int to_user) { unsigned long ret; void *addr; addr = kmap(page); if (to_user) { rds_stats_add(s_copy_to_user, bytes); ret = copy_to_user(ptr, addr + offset, bytes); } else { rds_stats_add(s_copy_from_user, bytes); ret = copy_from_user(addr + offset, ptr, bytes); } kunmap(page); return ret ? -EFAULT : 0; } EXPORT_SYMBOL_GPL(rds_page_copy_user); /** * rds_page_remainder_alloc - build up regions of a message. * * @scat: Scatter list for message * @bytes: the number of bytes needed. * @gfp: the waiting behaviour of the allocation * * @gfp is always ored with __GFP_HIGHMEM. Callers must be prepared to * kmap the pages, etc. * * If @bytes is at least a full page then this just returns a page from * alloc_page(). * * If @bytes is a partial page then this stores the unused region of the * page in a per-cpu structure. Future partial-page allocations may be * satisfied from that cached region. This lets us waste less memory on * small allocations with minimal complexity. It works because the transmit * path passes read-only page regions down to devices. They hold a page * reference until they are done with the region. */ int rds_page_remainder_alloc(struct scatterlist *scat, unsigned long bytes, gfp_t gfp) { struct rds_page_remainder *rem; unsigned long flags; struct page *page; int ret; gfp |= __GFP_HIGHMEM; /* jump straight to allocation if we're trying for a huge page */ if (bytes >= PAGE_SIZE) { page = alloc_page(gfp); if (!page) { ret = -ENOMEM; } else { sg_set_page(scat, page, PAGE_SIZE, 0); ret = 0; } goto out; } rem = &per_cpu(rds_page_remainders, get_cpu()); local_irq_save(flags); while (1) { /* avoid a tiny region getting stuck by tossing it */ if (rem->r_page && bytes > (PAGE_SIZE - rem->r_offset)) { rds_stats_inc(s_page_remainder_miss); __free_page(rem->r_page); rem->r_page = NULL; } /* hand out a fragment from the cached page */ if (rem->r_page && bytes <= (PAGE_SIZE - rem->r_offset)) { sg_set_page(scat, rem->r_page, bytes, rem->r_offset); get_page(sg_page(scat)); if (rem->r_offset != 0) rds_stats_inc(s_page_remainder_hit); rem->r_offset += ALIGN(bytes, 8); if (rem->r_offset >= PAGE_SIZE) { __free_page(rem->r_page); rem->r_page = NULL; } ret = 0; break; } /* alloc if there is nothing for us to use */ local_irq_restore(flags); put_cpu(); page = alloc_page(gfp); rem = &per_cpu(rds_page_remainders, get_cpu()); local_irq_save(flags); if (!page) { ret = -ENOMEM; break; } /* did someone race to fill the remainder before us? */ if (rem->r_page) { __free_page(page); continue; } /* otherwise install our page and loop around to alloc */ rem->r_page = page; rem->r_offset = 0; } local_irq_restore(flags); put_cpu(); out: rdsdebug("bytes %lu ret %d %p %u %u\n", bytes, ret, ret ? NULL : sg_page(scat), ret ? 0 : scat->offset, ret ? 0 : scat->length); return ret; } EXPORT_SYMBOL_GPL(rds_page_remainder_alloc); void rds_page_exit(void) { unsigned int cpu; for_each_possible_cpu(cpu) { struct rds_page_remainder *rem; rem = &per_cpu(rds_page_remainders, cpu); rdsdebug("cpu %u\n", cpu); if (rem->r_page) __free_page(rem->r_page); rem->r_page = NULL; } } =bf29bddf0417a4783da3b24e8c9e017ac649326f'>bf29bddf0417a4783da3b24e8c9e017ac649326f (diff)
efi/fdt: Avoid FDT manipulation after ExitBootServices()
Some AArch64 UEFI implementations disable the MMU in ExitBootServices(), after which unaligned accesses to RAM are no longer supported. Commit: abfb7b686a3e ("efi/libstub/arm*: Pass latest memory map to the kernel") fixed an issue in the memory map handling of the stub FDT code, but inadvertently created an issue with such firmware, by moving some of the FDT manipulation to after the invocation of ExitBootServices(). Given that the stub's libfdt implementation uses the ordinary, accelerated string functions, which rely on hardware handling of unaligned accesses, manipulating the FDT with the MMU off may result in alignment faults. So fix the situation by moving the update_fdt_memmap() call into the callback function invoked by efi_exit_boot_services() right before it calls the ExitBootServices() UEFI service (which is arguably a better place for it anyway) Note that disabling the MMU in ExitBootServices() is not compliant with the UEFI spec, and carries great risk due to the fact that switching from cached to uncached memory accesses halfway through compiler generated code (i.e., involving a stack) can never be done in a way that is architecturally safe. Fixes: abfb7b686a3e ("efi/libstub/arm*: Pass latest memory map to the kernel") Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Riku Voipio <riku.voipio@linaro.org> Cc: <stable@vger.kernel.org> Cc: mark.rutland@arm.com Cc: linux-efi@vger.kernel.org Cc: matt@codeblueprint.co.uk Cc: leif.lindholm@linaro.org Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/1485971102-23330-2-git-send-email-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'net/irda/ircomm')