From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AFC7CC38145 for ; Fri, 2 Sep 2022 14:31:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236545AbiIBObF (ORCPT ); Fri, 2 Sep 2022 10:31:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58400 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237362AbiIBO1j (ORCPT ); Fri, 2 Sep 2022 10:27:39 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C234315819D for ; Fri, 2 Sep 2022 06:54:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=mx58zQy98Wj+VFeO7kNG/+7nWSkg+eR2wmG7+5WoSrk=; b=NaNh3R/iwlKYiAWSqd7sSxJQkV UyvtNlhsdu8uUq+Z5CRjn88AROZ4+nBTZG4LJrKteU2OkXnZ3cqdb4A0D+OseLZSr31X2597PhrOR 0WFi8bfK+o8cNpVX2PPin1WtDWyNBSxovkHW05bjqCVsDRmifhnQoehDPV2dLMWUd1CzTLmsDWb46 F36FCkbJ03VbxFjRdofEkZ9PvRdAYTVvzFt0byhZ5K5bDyhtDqdu7gzTAWnMPg3z2NXCUUbvfuPgY 74OWWyB2Zy0FKFR8vOojteSYGNsmbu4in3biSK/2zn1tYQ7AtM/0LuygpkVRIq6Y3QmMBb9sDD5S2 E7qd/g2g==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1oU77M-008g8H-FS; Fri, 02 Sep 2022 13:54:03 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 2D3E13021FB; Fri, 2 Sep 2022 15:53:54 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id F33D92B8AE5A4; Fri, 2 Sep 2022 15:53:52 +0200 (CEST) Message-ID: <20220902130949.789826745@infradead.org> User-Agent: quilt/0.66 Date: Fri, 02 Sep 2022 15:06:58 +0200 From: Peter Zijlstra To: Thomas Gleixner Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, x86@kernel.org, Linus Torvalds , Tim Chen , Josh Poimboeuf , Andrew Cooper , Pawan Gupta , Johannes Wikner , Alyssa Milburn , Jann Horn , "H.J. Lu" , Joao Moreira , Joseph Nuzman , Steven Rostedt , Juergen Gross , Masami Hiramatsu , Alexei Starovoitov , Daniel Borkmann , K Prateek Nayak , Eric Dumazet Subject: [PATCH v2 33/59] objtool: Fix find_{symbol,func}_containing() References: <20220902130625.217071627@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Peter Zijlstra The current find_{symbol,func}_containing() functions are broken in the face of overlapping symbols, exactly the case that is needed for a new ibt/endbr supression. Import interval_tree_generic.h into the tools tree and convert the symbol tree to an interval tree to support proper range stabs. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) --- tools/include/linux/interval_tree_generic.h | 187 ++++++++++++++++++++++++++++ tools/objtool/elf.c | 93 +++++-------- tools/objtool/include/objtool/elf.h | 3 3 files changed, 229 insertions(+), 54 deletions(-) --- /dev/null +++ b/tools/include/linux/interval_tree_generic.h @@ -0,0 +1,187 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + Interval Trees + (C) 2012 Michel Lespinasse + + + include/linux/interval_tree_generic.h +*/ + +#include + +/* + * Template for implementing interval trees + * + * ITSTRUCT: struct type of the interval tree nodes + * ITRB: name of struct rb_node field within ITSTRUCT + * ITTYPE: type of the interval endpoints + * ITSUBTREE: name of ITTYPE field within ITSTRUCT holding last-in-subtree + * ITSTART(n): start endpoint of ITSTRUCT node n + * ITLAST(n): last endpoint of ITSTRUCT node n + * ITSTATIC: 'static' or empty + * ITPREFIX: prefix to use for the inline tree definitions + * + * Note - before using this, please consider if generic version + * (interval_tree.h) would work for you... + */ + +#define INTERVAL_TREE_DEFINE(ITSTRUCT, ITRB, ITTYPE, ITSUBTREE, \ + ITSTART, ITLAST, ITSTATIC, ITPREFIX) \ + \ +/* Callbacks for augmented rbtree insert and remove */ \ + \ +RB_DECLARE_CALLBACKS_MAX(static, ITPREFIX ## _augment, \ + ITSTRUCT, ITRB, ITTYPE, ITSUBTREE, ITLAST) \ + \ +/* Insert / remove interval nodes from the tree */ \ + \ +ITSTATIC void ITPREFIX ## _insert(ITSTRUCT *node, \ + struct rb_root_cached *root) \ +{ \ + struct rb_node **link = &root->rb_root.rb_node, *rb_parent = NULL; \ + ITTYPE start = ITSTART(node), last = ITLAST(node); \ + ITSTRUCT *parent; \ + bool leftmost = true; \ + \ + while (*link) { \ + rb_parent = *link; \ + parent = rb_entry(rb_parent, ITSTRUCT, ITRB); \ + if (parent->ITSUBTREE < last) \ + parent->ITSUBTREE = last; \ + if (start < ITSTART(parent)) \ + link = &parent->ITRB.rb_left; \ + else { \ + link = &parent->ITRB.rb_right; \ + leftmost = false; \ + } \ + } \ + \ + node->ITSUBTREE = last; \ + rb_link_node(&node->ITRB, rb_parent, link); \ + rb_insert_augmented_cached(&node->ITRB, root, \ + leftmost, &ITPREFIX ## _augment); \ +} \ + \ +ITSTATIC void ITPREFIX ## _remove(ITSTRUCT *node, \ + struct rb_root_cached *root) \ +{ \ + rb_erase_augmented_cached(&node->ITRB, root, &ITPREFIX ## _augment); \ +} \ + \ +/* \ + * Iterate over intervals intersecting [start;last] \ + * \ + * Note that a node's interval intersects [start;last] iff: \ + * Cond1: ITSTART(node) <= last \ + * and \ + * Cond2: start <= ITLAST(node) \ + */ \ + \ +static ITSTRUCT * \ +ITPREFIX ## _subtree_search(ITSTRUCT *node, ITTYPE start, ITTYPE last) \ +{ \ + while (true) { \ + /* \ + * Loop invariant: start <= node->ITSUBTREE \ + * (Cond2 is satisfied by one of the subtree nodes) \ + */ \ + if (node->ITRB.rb_left) { \ + ITSTRUCT *left = rb_entry(node->ITRB.rb_left, \ + ITSTRUCT, ITRB); \ + if (start <= left->ITSUBTREE) { \ + /* \ + * Some nodes in left subtree satisfy Cond2. \ + * Iterate to find the leftmost such node N. \ + * If it also satisfies Cond1, that's the \ + * match we are looking for. Otherwise, there \ + * is no matching interval as nodes to the \ + * right of N can't satisfy Cond1 either. \ + */ \ + node = left; \ + continue; \ + } \ + } \ + if (ITSTART(node) <= last) { /* Cond1 */ \ + if (start <= ITLAST(node)) /* Cond2 */ \ + return node; /* node is leftmost match */ \ + if (node->ITRB.rb_right) { \ + node = rb_entry(node->ITRB.rb_right, \ + ITSTRUCT, ITRB); \ + if (start <= node->ITSUBTREE) \ + continue; \ + } \ + } \ + return NULL; /* No match */ \ + } \ +} \ + \ +ITSTATIC ITSTRUCT * \ +ITPREFIX ## _iter_first(struct rb_root_cached *root, \ + ITTYPE start, ITTYPE last) \ +{ \ + ITSTRUCT *node, *leftmost; \ + \ + if (!root->rb_root.rb_node) \ + return NULL; \ + \ + /* \ + * Fastpath range intersection/overlap between A: [a0, a1] and \ + * B: [b0, b1] is given by: \ + * \ + * a0 <= b1 && b0 <= a1 \ + * \ + * ... where A holds the lock range and B holds the smallest \ + * 'start' and largest 'last' in the tree. For the later, we \ + * rely on the root node, which by augmented interval tree \ + * property, holds the largest value in its last-in-subtree. \ + * This allows mitigating some of the tree walk overhead for \ + * for non-intersecting ranges, maintained and consulted in O(1). \ + */ \ + node = rb_entry(root->rb_root.rb_node, ITSTRUCT, ITRB); \ + if (node->ITSUBTREE < start) \ + return NULL; \ + \ + leftmost = rb_entry(root->rb_leftmost, ITSTRUCT, ITRB); \ + if (ITSTART(leftmost) > last) \ + return NULL; \ + \ + return ITPREFIX ## _subtree_search(node, start, last); \ +} \ + \ +ITSTATIC ITSTRUCT * \ +ITPREFIX ## _iter_next(ITSTRUCT *node, ITTYPE start, ITTYPE last) \ +{ \ + struct rb_node *rb = node->ITRB.rb_right, *prev; \ + \ + while (true) { \ + /* \ + * Loop invariants: \ + * Cond1: ITSTART(node) <= last \ + * rb == node->ITRB.rb_right \ + * \ + * First, search right subtree if suitable \ + */ \ + if (rb) { \ + ITSTRUCT *right = rb_entry(rb, ITSTRUCT, ITRB); \ + if (start <= right->ITSUBTREE) \ + return ITPREFIX ## _subtree_search(right, \ + start, last); \ + } \ + \ + /* Move up the tree until we come from a node's left child */ \ + do { \ + rb = rb_parent(&node->ITRB); \ + if (!rb) \ + return NULL; \ + prev = &node->ITRB; \ + node = rb_entry(rb, ITSTRUCT, ITRB); \ + rb = node->ITRB.rb_right; \ + } while (prev == rb); \ + \ + /* Check if the node intersects [start;last] */ \ + if (last < ITSTART(node)) /* !Cond1 */ \ + return NULL; \ + else if (start <= ITLAST(node)) /* Cond2 */ \ + return node; \ + } \ +} --- a/tools/objtool/elf.c +++ b/tools/objtool/elf.c @@ -16,6 +16,7 @@ #include #include #include +#include #include #include @@ -50,38 +51,22 @@ static inline u32 str_hash(const char *s __elf_table(name); \ }) -static bool symbol_to_offset(struct rb_node *a, const struct rb_node *b) +static inline unsigned long __sym_start(struct symbol *s) { - struct symbol *sa = rb_entry(a, struct symbol, node); - struct symbol *sb = rb_entry(b, struct symbol, node); - - if (sa->offset < sb->offset) - return true; - if (sa->offset > sb->offset) - return false; - - if (sa->len < sb->len) - return true; - if (sa->len > sb->len) - return false; - - sa->alias = sb; - - return false; + return s->offset; } -static int symbol_by_offset(const void *key, const struct rb_node *node) +static inline unsigned long __sym_last(struct symbol *s) { - const struct symbol *s = rb_entry(node, struct symbol, node); - const unsigned long *o = key; + return s->offset + s->len - 1; +} - if (*o < s->offset) - return -1; - if (*o >= s->offset + s->len) - return 1; +INTERVAL_TREE_DEFINE(struct symbol, node, unsigned long, __subtree_last, + __sym_start, __sym_last, static, __sym) - return 0; -} +#define __sym_for_each(_iter, _tree, _start, _end) \ + for (_iter = __sym_iter_first((_tree), (_start), (_end)); \ + _iter; _iter = __sym_iter_next(_iter, (_start), (_end))) struct symbol_hole { unsigned long key; @@ -147,13 +132,12 @@ static struct symbol *find_symbol_by_ind struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset) { - struct rb_node *node; - - rb_for_each(node, &offset, &sec->symbol_tree, symbol_by_offset) { - struct symbol *s = rb_entry(node, struct symbol, node); + struct rb_root_cached *tree = (struct rb_root_cached *)&sec->symbol_tree; + struct symbol *iter; - if (s->offset == offset && s->type != STT_SECTION) - return s; + __sym_for_each(iter, tree, offset, offset) { + if (iter->offset == offset && iter->type != STT_SECTION) + return iter; } return NULL; @@ -161,13 +145,12 @@ struct symbol *find_symbol_by_offset(str struct symbol *find_func_by_offset(struct section *sec, unsigned long offset) { - struct rb_node *node; + struct rb_root_cached *tree = (struct rb_root_cached *)&sec->symbol_tree; + struct symbol *iter; - rb_for_each(node, &offset, &sec->symbol_tree, symbol_by_offset) { - struct symbol *s = rb_entry(node, struct symbol, node); - - if (s->offset == offset && s->type == STT_FUNC) - return s; + __sym_for_each(iter, tree, offset, offset) { + if (iter->offset == offset && iter->type == STT_FUNC) + return iter; } return NULL; @@ -175,13 +158,12 @@ struct symbol *find_func_by_offset(struc struct symbol *find_symbol_containing(const struct section *sec, unsigned long offset) { - struct rb_node *node; - - rb_for_each(node, &offset, &sec->symbol_tree, symbol_by_offset) { - struct symbol *s = rb_entry(node, struct symbol, node); + struct rb_root_cached *tree = (struct rb_root_cached *)&sec->symbol_tree; + struct symbol *iter; - if (s->type != STT_SECTION) - return s; + __sym_for_each(iter, tree, offset, offset) { + if (iter->type != STT_SECTION) + return iter; } return NULL; @@ -202,7 +184,7 @@ int find_symbol_hole_containing(const st /* * Find the rightmost symbol for which @offset is after it. */ - n = rb_find(&hole, &sec->symbol_tree, symbol_hole_by_offset); + n = rb_find(&hole, &sec->symbol_tree.rb_root, symbol_hole_by_offset); /* found a symbol that contains @offset */ if (n) @@ -224,13 +206,12 @@ int find_symbol_hole_containing(const st struct symbol *find_func_containing(struct section *sec, unsigned long offset) { - struct rb_node *node; - - rb_for_each(node, &offset, &sec->symbol_tree, symbol_by_offset) { - struct symbol *s = rb_entry(node, struct symbol, node); + struct rb_root_cached *tree = (struct rb_root_cached *)&sec->symbol_tree; + struct symbol *iter; - if (s->type == STT_FUNC) - return s; + __sym_for_each(iter, tree, offset, offset) { + if (iter->type == STT_FUNC) + return iter; } return NULL; @@ -373,6 +354,7 @@ static void elf_add_symbol(struct elf *e { struct list_head *entry; struct rb_node *pnode; + struct symbol *iter; INIT_LIST_HEAD(&sym->pv_target); sym->alias = sym; @@ -386,7 +368,12 @@ static void elf_add_symbol(struct elf *e sym->offset = sym->sym.st_value; sym->len = sym->sym.st_size; - rb_add(&sym->node, &sym->sec->symbol_tree, symbol_to_offset); + __sym_for_each(iter, &sym->sec->symbol_tree, sym->offset, sym->offset) { + if (iter->offset == sym->offset && iter->type == sym->type) + iter->alias = sym; + } + + __sym_insert(sym, &sym->sec->symbol_tree); pnode = rb_prev(&sym->node); if (pnode) entry = &rb_entry(pnode, struct symbol, node)->list; @@ -401,7 +388,7 @@ static void elf_add_symbol(struct elf *e * can exist within a function, confusing the sorting. */ if (!sym->len) - rb_erase(&sym->node, &sym->sec->symbol_tree); + __sym_remove(sym, &sym->sec->symbol_tree); } static int read_symbols(struct elf *elf) --- a/tools/objtool/include/objtool/elf.h +++ b/tools/objtool/include/objtool/elf.h @@ -30,7 +30,7 @@ struct section { struct hlist_node hash; struct hlist_node name_hash; GElf_Shdr sh; - struct rb_root symbol_tree; + struct rb_root_cached symbol_tree; struct list_head symbol_list; struct list_head reloc_list; struct section *base, *reloc; @@ -53,6 +53,7 @@ struct symbol { unsigned char bind, type; unsigned long offset; unsigned int len; + unsigned long __subtree_last; struct symbol *pfunc, *cfunc, *alias; u8 uaccess_safe : 1; u8 static_call_tramp : 1;