From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ard Biesheuvel Subject: [PATCH 1/6] extable: add support for relative extables to search and sort routines Date: Sun, 3 Jan 2016 17:05:52 +0100 Message-ID: <1451837157-447-2-git-send-email-ard.biesheuvel@linaro.org> References: <1451837157-447-1-git-send-email-ard.biesheuvel@linaro.org> Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=Qd2asYQFnQw2fF4FpFyCDQL+rTBxDs7n5fhzJe57xcc=; b=gbBoZ/3D2jZxoPC/9wvg9I1KJ5sHlJg67c1zUg8lxFGYaz/pmf9Ktb70kHJqE2HUBY 0JfBhP2AGVdq5wxdbU69I6KI3CjHu3Le6vfTRDVLa91w72XslFnxeCldCUKVJhPnN+n5 meo1HuABiGc8wKgTHeDsEcQe5OrVqJc9gJcvU= In-Reply-To: <1451837157-447-1-git-send-email-ard.biesheuvel@linaro.org> Sender: linux-alpha-owner@vger.kernel.org List-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-alpha@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linux-s390@vger.kernel.org, x86@kernel.org, hpa@zytor.com, mingo@redhat.com, heiko.carstens@de.ibm.com, schwidefsky@de.ibm.com, mattst88@gmail.com, ink@jurassic.park.msu.ru, rth@twiddle.net, tony.luck@intel.com, fenghua.yu@intel.com, catalin.marinas@arm.com, will.deacon@arm.com, arnd@arndb.de, akpm@linux-foundation.org Cc: mark.rutland@arm.com, marc.zyngier@arm.com, Ard Biesheuvel This adds support to the generic search_extable() and sort_extable() implementations for dealing with exception table entries whose fields contain relative offsets rather than absolute addresses. Signed-off-by: Ard Biesheuvel --- lib/extable.c | 50 ++++++++++++++++---- 1 file changed, 41 insertions(+), 9 deletions(-) diff --git a/lib/extable.c b/lib/extable.c index 4cac81ec225e..0be02ad561e9 100644 --- a/lib/extable.c +++ b/lib/extable.c @@ -14,7 +14,37 @@ #include #include +#ifndef ARCH_HAS_RELATIVE_EXTABLE +#define ex_to_insn(x) ((x)->insn) +#else +static inline unsigned long ex_to_insn(const struct exception_table_entry *x) +{ + return (unsigned long)&x->insn + x->insn; +} +#endif + #ifndef ARCH_HAS_SORT_EXTABLE +#ifndef ARCH_HAS_RELATIVE_EXTABLE +#define swap_ex NULL +#else +static void swap_ex(void *a, void *b, int size) +{ + struct exception_table_entry *x = a, *y = b, tmp; + int delta = b - a; + + tmp = *x; + x->insn = y->insn + delta; + y->insn = tmp.insn - delta; + +#ifdef swap_ex_entry_fixup + swap_ex_entry_fixup(x, y, tmp, delta); +#else + x->fixup = y->fixup + delta; + y->fixup = tmp.fixup - delta; +#endif +} +#endif /* ARCH_HAS_RELATIVE_EXTABLE */ + /* * The exception table needs to be sorted so that the binary * search that we use to find entries in it works properly. @@ -26,9 +56,9 @@ static int cmp_ex(const void *a, const void *b) const struct exception_table_entry *x = a, *y = b; /* avoid overflow */ - if (x->insn > y->insn) + if (ex_to_insn(x) > ex_to_insn(y)) return 1; - if (x->insn < y->insn) + if (ex_to_insn(x) < ex_to_insn(y)) return -1; return 0; } @@ -37,7 +67,7 @@ void sort_extable(struct exception_table_entry *start, struct exception_table_entry *finish) { sort(start, finish - start, sizeof(struct exception_table_entry), - cmp_ex, NULL); + cmp_ex, swap_ex); } #ifdef CONFIG_MODULES @@ -48,13 +78,15 @@ void sort_extable(struct exception_table_entry *start, void trim_init_extable(struct module *m) { /*trim the beginning*/ - while (m->num_exentries && within_module_init(m->extable[0].insn, m)) { + while (m->num_exentries && + within_module_init(ex_to_insn(&m->extable[0]), m)) { m->extable++; m->num_exentries--; } /*trim the end*/ while (m->num_exentries && - within_module_init(m->extable[m->num_exentries-1].insn, m)) + within_module_init(ex_to_insn(&m->extable[m->num_exentries - 1]), + m)) m->num_exentries--; } #endif /* CONFIG_MODULES */ @@ -81,13 +113,13 @@ search_extable(const struct exception_table_entry *first, * careful, the distance between value and insn * can be larger than MAX_LONG: */ - if (mid->insn < value) + if (ex_to_insn(mid) < value) first = mid + 1; - else if (mid->insn > value) + else if (ex_to_insn(mid) > value) last = mid - 1; else return mid; - } - return NULL; + } + return NULL; } #endif -- 1.9.1