/* ASN.1 Object identifier (OID) registry * * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public Licence * as published by the Free Software Foundation; either version * 2 of the Licence, or (at your option) any later version. */ #include #include #include #include #include #include #include "oid_registry_data.c" MODULE_DESCRIPTION("OID Registry"); MODULE_AUTHOR("Red Hat, Inc."); MODULE_LICENSE("GPL"); /** * look_up_OID - Find an OID registration for the specified data * @data: Binary representation of the OID * @datasize: Size of the binary representation */ enum OID look_up_OID(const void *data, size_t datasize) { const unsigned char *octets = data; enum OID oid; unsigned char xhash; unsigned i, j, k, hash; size_t len; /* Hash the OID data */ hash = datasize - 1; for (i = 0; i < datasize; i++) hash += octets[i] * 33; hash = (hash >> 24) ^ (hash >> 16) ^ (hash >> 8) ^ hash; hash &= 0xff; /* Binary search the OID registry. OIDs are stored in ascending order * of hash value then ascending order of size and then in ascending * order of reverse value. */ i = 0; k = OID__NR; while (i < k) { j = (i + k) / 2; xhash = oid_search_table[j].hash; if (xhash > hash) { k = j; continue; } if (xhash < hash) { i = j + 1; continue; } oid = oid_search_table[j].oid; len = oid_index[oid + 1] - oid_index[oid]; if (len > datasize) { k = j; continue; } if (len < datasize) { i = j + 1; continue; } /* Variation is most likely to be at the tail end of the * OID, so do the comparison in reverse. */ while (len > 0) { unsigned char a = oid_data[oid_index[oid] + --len]; unsigned char b = octets[len]; if (a > b) { k = j; goto next; } if (a < b) { i = j + 1; goto next; } } return oid; next: ; } return OID__NR; } EXPORT_SYMBOL_GPL(look_up_OID); /* * sprint_OID - Print an Object Identifier into a buffer * @data: The encoded OID to print * @datasize: The size of the encoded OID * @buffer: The buffer to render into * @bufsize: The size of the buffer * * The OID is rendered into the buffer in "a.b.c.d" format and the number of * bytes is returned. -EBADMSG is returned if the data could not be intepreted * and -ENOBUFS if the buffer was too small. */ int sprint_oid(const void *data, size_t datasize, char *buffer, size_t bufsize) { const unsigned char *v = data, *end = v + datasize; unsigned long num; unsigned char n; size_t ret; int count; if (v >= end) return -EBADMSG; n = *v++; ret = count = snprintf(buffer, bufsize, "%u.%u", n / 40, n % 40); buffer += count; bufsize -= count; if (bufsize == 0) return -ENOBUFS; while (v < end) { num = 0; n = *v++; if (!(n & 0x80)) { num = n; } else { num = n & 0x7f; do { if (v >= end) return -EBADMSG; n = *v++; num <<= 7; num |= n & 0x7f; } while (n & 0x80); } ret += count = snprintf(buffer, bufsize, ".%lu", num); buffer += count; bufsize -= count; if (bufsize == 0) return -ENOBUFS; } return ret; } EXPORT_SYMBOL_GPL(sprint_oid); /** * sprint_OID - Print an Object Identifier into a buffer * @oid: The OID to print * @buffer: The buffer to render into * @bufsize: The size of the buffer * * The OID is rendered into the buffer in "a.b.c.d" format and the number of * bytes is returned. */ int sprint_OID(enum OID oid, char *buffer, size_t bufsize) { int ret; BUG_ON(oid >= OID__NR); ret = sprint_oid(oid_data + oid_index[oid], oid_index[oid + 1] - oid_index[oid], buffer, bufsize); BUG_ON(ret == -EBADMSG); return ret; } EXPORT_SYMBOL_GPL(sprint_OID); gan@imgtec.com>2016-05-27 22:25:23 +0100 committerRalf Baechle <ralf@linux-mips.org>2016-05-28 12:35:11 +0200 commitaa76042a016474775ccd187c068669148c30c3bb (patch) tree8de1af48b851f387c8262cc88a1793036e5d4531 parent6446e6cf440f6ee0f8b64c32968a8434205c1f59 (diff)

MIPS: Fix 64-bit HTW configuration

The Hardware page Table Walker (HTW) is being misconfigured on 64-bit kernels. The PWSize.PS (pointer size) bit determines whether pointers within directories are loaded as 32-bit or 64-bit addresses, but was never being set to 1 for 64-bit kernels where the unsigned long in pgd_t is 64-bits wide. This actually reduces rather than improves performance when the HTW is enabled on P6600 since the HTW is initiated lots, but walks are all aborted due I think to bad intermediate pointers. Since we were already taking the width of the PTEs into account by setting PWSize.PTEW, which is the left shift applied to the page table index *in addition to* the native pointer size, we also need to reduce PTEW by 1 when PS=1. This is done by calculating PTEW based on the relative size of pte_t compared to pgd_t. Finally in order for the HTW to be used when PS=1, the appropriate XK/XS/XU bits corresponding to the different 64-bit segments need to be set in PWCtl. We enable only XU for now to enable walking for XUSeg. Supporting walking for XKSeg would be a bit more involved so is left for a future patch. It would either require the use of a per-CPU top level base directory if supported by the HTW (a bit like pgd_current but with a second entry pointing at swapper_pg_dir), or the HTW would prepend bit 63 of the address to the global directory index which doesn't really match how we split user and kernel page directories. Fixes: cab25bc7537b ("MIPS: Extend hardware table walking support to MIPS64") Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13364/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>