From 26a28fa4fea5b8c65713aa50c124f76a88c7924d Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 13 May 2009 22:56:38 +0000 Subject: add generic lib/checksum.c Add a generic (unoptimized) implementation of checksum.c in pure C for use by all architectures that cannot be bother with implementing their own version. Based on microblaze code by Michal Simek Cc: Michal Simek Signed-off-by: Remis Lima Baima Signed-off-by: Arnd Bergmann --- lib/Makefile | 2 + lib/checksum.c | 193 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 195 insertions(+) create mode 100644 lib/checksum.c (limited to 'lib') diff --git a/lib/Makefile b/lib/Makefile index 33a40e40e3e..b6869e12e74 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -92,6 +92,8 @@ obj-$(CONFIG_NLATTR) += nlattr.o obj-$(CONFIG_DMA_API_DEBUG) += dma-debug.o +obj-$(CONFIG_GENERIC_CSUM) += checksum.o + hostprogs-y := gen_crc32table clean-files := crc32table.h diff --git a/lib/checksum.c b/lib/checksum.c new file mode 100644 index 00000000000..12e5a1c91cd --- /dev/null +++ b/lib/checksum.c @@ -0,0 +1,193 @@ +/* + * + * INET An implementation of the TCP/IP protocol suite for the LINUX + * operating system. INET is implemented using the BSD Socket + * interface as the means of communication with the user level. + * + * IP/TCP/UDP checksumming routines + * + * Authors: Jorge Cwik, + * Arnt Gulbrandsen, + * Tom May, + * Andreas Schwab, + * Lots of code moved from tcp.c and ip.c; see those files + * for more names. + * + * 03/02/96 Jes Sorensen, Andreas Schwab, Roman Hodek: + * Fixed some nasty bugs, causing some horrible crashes. + * A: At some points, the sum (%0) was used as + * length-counter instead of the length counter + * (%1). Thanks to Roman Hodek for pointing this out. + * B: GCC seems to mess up if one uses too many + * data-registers to hold input values and one tries to + * specify d0 and d1 as scratch registers. Letting gcc + * choose these registers itself solves the problem. + * + * 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. + */ + +/* Revised by Kenneth Albanowski for m68knommu. Basic problem: unaligned access + kills, so most of the assembly has to go. */ + +#include +#include + +#include + +static inline unsigned short from32to16(unsigned long x) +{ + /* add up 16-bit and 16-bit for 16+c bit */ + x = (x & 0xffff) + (x >> 16); + /* add up carry.. */ + x = (x & 0xffff) + (x >> 16); + return x; +} + +static unsigned int do_csum(const unsigned char *buff, int len) +{ + int odd, count; + unsigned long result = 0; + + if (len <= 0) + goto out; + odd = 1 & (unsigned long) buff; + if (odd) { + result = *buff; + len--; + buff++; + } + count = len >> 1; /* nr of 16-bit words.. */ + if (count) { + if (2 & (unsigned long) buff) { + result += *(unsigned short *) buff; + count--; + len -= 2; + buff += 2; + } + count >>= 1; /* nr of 32-bit words.. */ + if (count) { + unsigned long carry = 0; + do { + unsigned long w = *(unsigned long *) buff; + count--; + buff += 4; + result += carry; + result += w; + carry = (w > result); + } while (count); + result += carry; + result = (result & 0xffff) + (result >> 16); + } + if (len & 2) { + result += *(unsigned short *) buff; + buff += 2; + } + } + if (len & 1) + result += (*buff << 8); + result = from32to16(result); + if (odd) + result = ((result >> 8) & 0xff) | ((result & 0xff) << 8); +out: + return result; +} + +/* + * This is a version of ip_compute_csum() optimized for IP headers, + * which always checksum on 4 octet boundaries. + */ +__sum16 ip_fast_csum(const void *iph, unsigned int ihl) +{ + return (__force __sum16)~do_csum(iph, ihl*4); +} +EXPORT_SYMBOL(ip_fast_csum); + +/* + * computes the checksum of a memory block at buff, length len, + * and adds in "sum" (32-bit) + * + * returns a 32-bit number suitable for feeding into itself + * or csum_tcpudp_magic + * + * this function must be called with even lengths, except + * for the last fragment, which may be odd + * + * it's best to have buff aligned on a 32-bit boundary + */ +__wsum csum_partial(const void *buff, int len, __wsum wsum) +{ + unsigned int sum = (__force unsigned int)wsum; + unsigned int result = do_csum(buff, len); + + /* add in old sum, and carry.. */ + result += sum; + if (sum > result) + result += 1; + return (__force __wsum)result; +} +EXPORT_SYMBOL(csum_partial); + +/* + * this routine is used for miscellaneous IP-like checksums, mainly + * in icmp.c + */ +__sum16 ip_compute_csum(const void *buff, int len) +{ + return (__force __sum16)~do_csum(buff, len); +} +EXPORT_SYMBOL(ip_compute_csum); + +/* + * copy from fs while checksumming, otherwise like csum_partial + */ +__wsum +csum_partial_copy_from_user(const void __user *src, void *dst, int len, + __wsum sum, int *csum_err) +{ + int missing; + + missing = __copy_from_user(dst, src, len); + if (missing) { + memset(dst + len - missing, 0, missing); + *csum_err = -EFAULT; + } else + *csum_err = 0; + + return csum_partial(dst, len, sum); +} +EXPORT_SYMBOL(csum_partial_copy_from_user); + +/* + * copy from ds while checksumming, otherwise like csum_partial + */ +__wsum +csum_partial_copy(const void *src, void *dst, int len, __wsum sum) +{ + memcpy(dst, src, len); + return csum_partial(dst, len, sum); +} +EXPORT_SYMBOL(csum_partial_copy); + +#ifndef csum_tcpudp_nofold +__wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, + unsigned short len, + unsigned short proto, + __wsum sum) +{ + unsigned long long s = (__force u32)sum; + + s += (__force u32)saddr; + s += (__force u32)daddr; +#ifdef __BIG_ENDIAN + s += proto + len; +#else + s += (proto + len) << 8; +#endif + s += (s >> 32); + return (__force __wsum)s; +} +EXPORT_SYMBOL(csum_tcpudp_nofold); +#endif -- cgit v1.2.3 From ad6561dffa17f17bb68d7207d422c26c381c4313 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Fri, 12 Jun 2009 21:47:03 -0600 Subject: module: trim exception table on init free. It's theoretically possible that there are exception table entries which point into the (freed) init text of modules. These could cause future problems if other modules get loaded into that memory and cause an exception as we'd see the wrong fixup. The only case I know of is kvm-intel.ko (when CONFIG_CC_OPTIMIZE_FOR_SIZE=n). Amerigo fixed this long-standing FIXME in the x86 version, but this patch is more general. This implements trim_init_extable(); most archs are simple since they use the standard lib/extable.c sort code. Alpha and IA64 use relative addresses in their fixups, so thier trimming is a slight variation. Sparc32 is unique; it doesn't seem to define ARCH_HAS_SORT_EXTABLE, yet it defines its own sort_extable() which overrides the one in lib. It doesn't sort, so we have to mark deleted entries instead of actually trimming them. Inspired-by: Amerigo Wang Signed-off-by: Rusty Russell Cc: linux-alpha@vger.kernel.org Cc: sparclinux@vger.kernel.org Cc: linux-ia64@vger.kernel.org --- arch/alpha/mm/extable.c | 21 +++++++++++++++++++++ arch/ia64/mm/extable.c | 26 ++++++++++++++++++++++++++ arch/sparc/include/asm/uaccess_32.h | 3 +++ arch/sparc/mm/extable.c | 29 +++++++++++++++++++++++++++++ include/linux/module.h | 1 + kernel/module.c | 1 + lib/extable.c | 21 ++++++++++++++++++++- 7 files changed, 101 insertions(+), 1 deletion(-) (limited to 'lib') diff --git a/arch/alpha/mm/extable.c b/arch/alpha/mm/extable.c index 62dc379d301..813c9b63c0e 100644 --- a/arch/alpha/mm/extable.c +++ b/arch/alpha/mm/extable.c @@ -48,6 +48,27 @@ void sort_extable(struct exception_table_entry *start, cmp_ex, swap_ex); } +#ifdef CONFIG_MODULES +/* + * Any entry referring to the module init will be at the beginning or + * the end. + */ +void trim_init_extable(struct module *m) +{ + /*trim the beginning*/ + while (m->num_exentries && + within_module_init(ex_to_addr(&m->extable[0]), m)) { + m->extable++; + m->num_exentries--; + } + /*trim the end*/ + while (m->num_exentries && + within_module_init(ex_to_addr(&m->extable[m->num_exentries-1]), + m)) + m->num_exentries--; +} +#endif /* CONFIG_MODULES */ + const struct exception_table_entry * search_extable(const struct exception_table_entry *first, const struct exception_table_entry *last, diff --git a/arch/ia64/mm/extable.c b/arch/ia64/mm/extable.c index 71c50dd8f87..e95d5ad9285 100644 --- a/arch/ia64/mm/extable.c +++ b/arch/ia64/mm/extable.c @@ -53,6 +53,32 @@ void sort_extable (struct exception_table_entry *start, cmp_ex, swap_ex); } +static inline unsigned long ex_to_addr(const struct exception_table_entry *x) +{ + return (unsigned long)&x->insn + x->insn; +} + +#ifdef CONFIG_MODULES +/* + * Any entry referring to the module init will be at the beginning or + * the end. + */ +void trim_init_extable(struct module *m) +{ + /*trim the beginning*/ + while (m->num_exentries && + within_module_init(ex_to_addr(&m->extable[0]), m)) { + m->extable++; + m->num_exentries--; + } + /*trim the end*/ + while (m->num_exentries && + within_module_init(ex_to_addr(&m->extable[m->num_exentries-1]), + m)) + m->num_exentries--; +} +#endif /* CONFIG_MODULES */ + const struct exception_table_entry * search_extable (const struct exception_table_entry *first, const struct exception_table_entry *last, diff --git a/arch/sparc/include/asm/uaccess_32.h b/arch/sparc/include/asm/uaccess_32.h index 47d5619d43f..8303ac48103 100644 --- a/arch/sparc/include/asm/uaccess_32.h +++ b/arch/sparc/include/asm/uaccess_32.h @@ -17,6 +17,9 @@ #ifndef __ASSEMBLY__ +#define ARCH_HAS_SORT_EXTABLE +#define ARCH_HAS_SEARCH_EXTABLE + /* Sparc is not segmented, however we need to be able to fool access_ok() * when doing system calls from kernel mode legitimately. * diff --git a/arch/sparc/mm/extable.c b/arch/sparc/mm/extable.c index 16cc28935e3..a61c349448e 100644 --- a/arch/sparc/mm/extable.c +++ b/arch/sparc/mm/extable.c @@ -28,6 +28,10 @@ search_extable(const struct exception_table_entry *start, * word 3: last insn address + 4 bytes * word 4: fixup code address * + * Deleted entries are encoded as: + * word 1: unused + * word 2: -1 + * * See asm/uaccess.h for more details. */ @@ -39,6 +43,10 @@ search_extable(const struct exception_table_entry *start, continue; } + /* A deleted entry; see trim_init_extable */ + if (walk->fixup == -1) + continue; + if (walk->insn == value) return walk; } @@ -57,6 +65,27 @@ search_extable(const struct exception_table_entry *start, return NULL; } +#ifdef CONFIG_MODULES +/* We could memmove them around; easier to mark the trimmed ones. */ +void trim_init_extable(struct module *m) +{ + unsigned int i; + bool range; + + for (i = 0; i < m->num_exentries; i += range ? 2 : 1) { + range = m->extable[i].fixup == 0; + + if (within_module_init(m->extable[i].insn, m)) { + m->extable[i].fixup = -1; + if (range) + m->extable[i+1].fixup = -1; + } + if (range) + i++; + } +} +#endif /* CONFIG_MODULES */ + /* Special extable search, which handles ranges. Returns fixup */ unsigned long search_extables_range(unsigned long addr, unsigned long *g2) { diff --git a/include/linux/module.h b/include/linux/module.h index a8f2c0aa4c3..a7bc6e7b43a 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -77,6 +77,7 @@ search_extable(const struct exception_table_entry *first, void sort_extable(struct exception_table_entry *start, struct exception_table_entry *finish); void sort_main_extable(void); +void trim_init_extable(struct module *m); #ifdef MODULE #define MODULE_GENERIC_TABLE(gtype,name) \ diff --git a/kernel/module.c b/kernel/module.c index 35f7de00bf0..e4ab36ce767 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2455,6 +2455,7 @@ SYSCALL_DEFINE3(init_module, void __user *, umod, mutex_lock(&module_mutex); /* Drop initial reference. */ module_put(mod); + trim_init_extable(mod); module_free(mod, mod->module_init); mod->module_init = NULL; mod->init_size = 0; diff --git a/lib/extable.c b/lib/extable.c index 179c0874559..4cac81ec225 100644 --- a/lib/extable.c +++ b/lib/extable.c @@ -39,7 +39,26 @@ void sort_extable(struct exception_table_entry *start, sort(start, finish - start, sizeof(struct exception_table_entry), cmp_ex, NULL); } -#endif + +#ifdef CONFIG_MODULES +/* + * If the exception table is sorted, any referring to the module init + * will be at the beginning or the end. + */ +void trim_init_extable(struct module *m) +{ + /*trim the beginning*/ + while (m->num_exentries && within_module_init(m->extable[0].insn, m)) { + m->extable++; + m->num_exentries--; + } + /*trim the end*/ + while (m->num_exentries && + within_module_init(m->extable[m->num_exentries-1].insn, m)) + m->num_exentries--; +} +#endif /* CONFIG_MODULES */ +#endif /* !ARCH_HAS_SORT_EXTABLE */ #ifndef ARCH_HAS_SEARCH_EXTABLE /* -- cgit v1.2.3