/* * net/core/dst_cache.c - dst entry cache * * Copyright (c) 2016 Paolo Abeni * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. */ #include #include #include #include #if IS_ENABLED(CONFIG_IPV6) #include #endif #include struct dst_cache_pcpu { unsigned long refresh_ts; struct dst_entry *dst; u32 cookie; union { struct in_addr in_saddr; struct in6_addr in6_saddr; }; }; static void dst_cache_per_cpu_dst_set(struct dst_cache_pcpu *dst_cache, struct dst_entry *dst, u32 cookie) { dst_release(dst_cache->dst); if (dst) dst_hold(dst); dst_cache->cookie = cookie; dst_cache->dst = dst; } static struct dst_entry *dst_cache_per_cpu_get(struct dst_cache *dst_cache, struct dst_cache_pcpu *idst) { struct dst_entry *dst; dst = idst->dst; if (!dst) goto fail; /* the cache already hold a dst reference; it can't go away */ dst_hold(dst); if (unlikely(!time_after(idst->refresh_ts, dst_cache->reset_ts) || (dst->obsolete && !dst->ops->check(dst, idst->cookie)))) { dst_cache_per_cpu_dst_set(idst, NULL, 0); dst_release(dst); goto fail; } return dst; fail: idst->refresh_ts = jiffies; return NULL; } struct dst_entry *dst_cache_get(struct dst_cache *dst_cache) { if (!dst_cache->cache) return NULL; return dst_cache_per_cpu_get(dst_cache, this_cpu_ptr(dst_cache->cache)); } EXPORT_SYMBOL_GPL(dst_cache_get); struct rtable *dst_cache_get_ip4(struct dst_cache *dst_cache, __be32 *saddr) { struct dst_cache_pcpu *idst; struct dst_entry *dst; if (!dst_cache->cache) return NULL; idst = this_cpu_ptr(dst_cache->cache); dst = dst_cache_per_cpu_get(dst_cache, idst); if (!dst) return NULL; *saddr = idst->in_saddr.s_addr; return container_of(dst, struct rtable, dst); } EXPORT_SYMBOL_GPL(dst_cache_get_ip4); void dst_cache_set_ip4(struct dst_cache *dst_cache, struct dst_entry *dst, __be32 saddr) { struct dst_cache_pcpu *idst; if (!dst_cache->cache) return; idst = this_cpu_ptr(dst_cache->cache); dst_cache_per_cpu_dst_set(idst, dst, 0); idst->in_saddr.s_addr = saddr; } EXPORT_SYMBOL_GPL(dst_cache_set_ip4); #if IS_ENABLED(CONFIG_IPV6) void dst_cache_set_ip6(struct dst_cache *dst_cache, struct dst_entry *dst, const struct in6_addr *addr) { struct dst_cache_pcpu *idst; if (!dst_cache->cache) return; idst = this_cpu_ptr(dst_cache->cache); dst_cache_per_cpu_dst_set(this_cpu_ptr(dst_cache->cache), dst, rt6_get_cookie((struct rt6_info *)dst)); idst->in6_saddr = *addr; } EXPORT_SYMBOL_GPL(dst_cache_set_ip6); struct dst_entry *dst_cache_get_ip6(struct dst_cache *dst_cache, struct in6_addr *saddr) { struct dst_cache_pcpu *idst; struct dst_entry *dst; if (!dst_cache->cache) return NULL; idst = this_cpu_ptr(dst_cache->cache); dst = dst_cache_per_cpu_get(dst_cache, idst); if (!dst) return NULL; *saddr = idst->in6_saddr; return dst; } EXPORT_SYMBOL_GPL(dst_cache_get_ip6); #endif int dst_cache_init(struct dst_cache *dst_cache, gfp_t gfp) { dst_cache->cache = alloc_percpu_gfp(struct dst_cache_pcpu, gfp | __GFP_ZERO); if (!dst_cache->cache) return -ENOMEM; dst_cache_reset(dst_cache); return 0; } EXPORT_SYMBOL_GPL(dst_cache_init); void dst_cache_destroy(struct dst_cache *dst_cache) { int i; if (!dst_cache->cache) return; for_each_possible_cpu(i) dst_release(per_cpu_ptr(dst_cache->cache, i)->dst); free_percpu(dst_cache->cache); } EXPORT_SYMBOL_GPL(dst_cache_destroy); ='content'>
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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2017-02-01 17:45:02 +0000
committerIngo Molnar <mingo@kernel.org>2017-02-01 21:17:49 +0100
commitc8f325a59cfc718d13a50fbc746ed9b415c25e92 (patch)
treed53fbdac9d0781e39a13b2ac6b2bd258cf3b4140 /tools/perf/Documentation/perf-probe.txt
parentbf29bddf0417a4783da3b24e8c9e017ac649326f (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 'tools/perf/Documentation/perf-probe.txt')