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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 894C1C2BA83 for ; Wed, 12 Feb 2020 12:51:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5785D20714 for ; Wed, 12 Feb 2020 12:51:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728009AbgBLMu7 (ORCPT ); Wed, 12 Feb 2020 07:50:59 -0500 Received: from mga06.intel.com ([134.134.136.31]:63674 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725887AbgBLMu7 (ORCPT ); Wed, 12 Feb 2020 07:50:59 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 12 Feb 2020 04:50:58 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,428,1574150400"; d="scan'208";a="237702441" Received: from ahunter-desktop.fi.intel.com ([10.237.72.167]) by orsmga006.jf.intel.com with ESMTP; 12 Feb 2020 04:50:54 -0800 From: Adrian Hunter To: Peter Zijlstra Cc: Ingo Molnar , Borislav Petkov , "H . Peter Anvin" , x86@kernel.org, Mark Rutland , Alexander Shishkin , Mathieu Poirier , Leo Yan , Arnaldo Carvalho de Melo , Jiri Olsa , linux-kernel@vger.kernel.org Subject: [PATCH V2 03/13] kprobes: Add symbols for kprobe insn pages Date: Wed, 12 Feb 2020 14:49:39 +0200 Message-Id: <20200212124949.3589-4-adrian.hunter@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200212124949.3589-1-adrian.hunter@intel.com> References: <20200212124949.3589-1-adrian.hunter@intel.com> Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Symbols are needed for tools to describe instruction addresses. Pages allocated for kprobe's purposes need symbols to be created for them. Add such symbols to be visible via /proc/kallsyms. Signed-off-by: Adrian Hunter --- include/linux/kprobes.h | 28 +++++++++++++++++++++++++ kernel/kallsyms.c | 32 +++++++++++++++++++++++++---- kernel/kprobes.c | 45 +++++++++++++++++++++++++++++++++++++++++ 3 files changed, 101 insertions(+), 4 deletions(-) diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index 04bdaf01112c..6613682f3961 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -242,6 +242,7 @@ struct kprobe_insn_cache { struct mutex mutex; void *(*alloc)(void); /* allocate insn page */ void (*free)(void *); /* free insn page */ + const char *sym; /* symbol for insn pages */ struct list_head pages; /* list of kprobe_insn_page */ size_t insn_size; /* size of instruction slot */ int nr_garbage; @@ -272,6 +273,8 @@ static inline bool is_kprobe_##__name##_slot(unsigned long addr) \ { \ return __is_insn_slot_addr(&kprobe_##__name##_slots, addr); \ } +#define KPROBE_INSN_PAGE_SYM "kprobe_insn_page" +#define KPROBE_OPTINSN_PAGE_SYM "kprobe_optinsn_page" #else /* __ARCH_WANT_KPROBES_INSN_SLOT */ #define DEFINE_INSN_CACHE_OPS(__name) \ static inline bool is_kprobe_##__name##_slot(unsigned long addr) \ @@ -373,6 +376,13 @@ void dump_kprobe(struct kprobe *kp); void *alloc_insn_page(void); void free_insn_page(void *page); +int kprobe_get_kallsym(unsigned int symnum, unsigned long *value, char *type, + char *sym); +int kprobe_cache_get_kallsym(struct kprobe_insn_cache *c, unsigned int *symnum, + unsigned long *value, char *type, char *sym); + +int arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value, + char *type, char *sym); #else /* !CONFIG_KPROBES: */ static inline int kprobes_built_in(void) @@ -435,6 +445,24 @@ static inline bool within_kprobe_blacklist(unsigned long addr) { return true; } +static inline int kprobe_get_kallsym(unsigned int symnum, unsigned long *value, + char *type, char *sym) +{ + return 0; +} +static inline int kprobe_cache_get_kallsym(struct kprobe_insn_cache *c, + unsigned int *symnum, + unsigned long *value, char *type, + char *sym) +{ + return 0; +} +static inline int arch_kprobe_get_kallsym(unsigned int *symnum, + unsigned long *value, char *type, + char *sym) +{ + return 0; +} #endif /* CONFIG_KPROBES */ static inline int disable_kretprobe(struct kretprobe *rp) { diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index 136ce049c4ad..fd5579171087 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -24,6 +24,7 @@ #include #include #include +#include #include /* @@ -438,6 +439,7 @@ struct kallsym_iter { loff_t pos_arch_end; loff_t pos_mod_end; loff_t pos_ftrace_mod_end; + loff_t pos_bpf_end; unsigned long value; unsigned int nameoff; /* If iterating in core kernel symbols. */ char type; @@ -497,11 +499,28 @@ static int get_ksymbol_ftrace_mod(struct kallsym_iter *iter) static int get_ksymbol_bpf(struct kallsym_iter *iter) { + int ret; + strlcpy(iter->module_name, "bpf", MODULE_NAME_LEN); iter->exported = 0; - return bpf_get_kallsym(iter->pos - iter->pos_ftrace_mod_end, - &iter->value, &iter->type, - iter->name) < 0 ? 0 : 1; + ret = bpf_get_kallsym(iter->pos - iter->pos_ftrace_mod_end, + &iter->value, &iter->type, + iter->name); + if (ret < 0) { + iter->pos_bpf_end = iter->pos; + return 0; + } + + return 1; +} + +static int get_ksymbol_kprobe(struct kallsym_iter *iter) +{ + strlcpy(iter->module_name, "kprobe", MODULE_NAME_LEN); + iter->exported = 0; + return kprobe_get_kallsym(iter->pos - iter->pos_bpf_end, + &iter->value, &iter->type, + iter->name) < 0 ? 0 : 1; } /* Returns space to next name. */ @@ -528,6 +547,7 @@ static void reset_iter(struct kallsym_iter *iter, loff_t new_pos) iter->pos_arch_end = 0; iter->pos_mod_end = 0; iter->pos_ftrace_mod_end = 0; + iter->pos_bpf_end = 0; } } @@ -552,7 +572,11 @@ static int update_iter_mod(struct kallsym_iter *iter, loff_t pos) get_ksymbol_ftrace_mod(iter)) return 1; - return get_ksymbol_bpf(iter); + if ((!iter->pos_bpf_end || iter->pos_bpf_end > pos) && + get_ksymbol_bpf(iter)) + return 1; + + return get_ksymbol_kprobe(iter); } /* Returns false if pos at or past end of file. */ diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 2625c241ac00..229d1b596690 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -118,6 +118,7 @@ struct kprobe_insn_cache kprobe_insn_slots = { .mutex = __MUTEX_INITIALIZER(kprobe_insn_slots.mutex), .alloc = alloc_insn_page, .free = free_insn_page, + .sym = KPROBE_INSN_PAGE_SYM, .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages), .insn_size = MAX_INSN_SIZE, .nr_garbage = 0, @@ -296,6 +297,7 @@ struct kprobe_insn_cache kprobe_optinsn_slots = { .mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex), .alloc = alloc_insn_page, .free = free_insn_page, + .sym = KPROBE_OPTINSN_PAGE_SYM, .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages), /* .insn_size is initialized later */ .nr_garbage = 0, @@ -2179,6 +2181,49 @@ int kprobe_add_area_blacklist(unsigned long start, unsigned long end) return 0; } +int kprobe_cache_get_kallsym(struct kprobe_insn_cache *c, unsigned int *symnum, + unsigned long *value, char *type, char *sym) +{ + struct kprobe_insn_page *kip; + int ret = -ERANGE; + + rcu_read_lock(); + list_for_each_entry_rcu(kip, &c->pages, list) { + if ((*symnum)--) + continue; + strlcpy(sym, c->sym, KSYM_NAME_LEN); + *type = 't'; + *value = (unsigned long)kip->insns; + ret = 0; + break; + } + rcu_read_unlock(); + + return ret; +} + +int __weak arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value, + char *type, char *sym) +{ + return -ERANGE; +} + +int kprobe_get_kallsym(unsigned int symnum, unsigned long *value, char *type, + char *sym) +{ +#ifdef __ARCH_WANT_KPROBES_INSN_SLOT + if (!kprobe_cache_get_kallsym(&kprobe_insn_slots, &symnum, value, type, sym)) + return 0; +#ifdef CONFIG_OPTPROBES + if (!kprobe_cache_get_kallsym(&kprobe_optinsn_slots, &symnum, value, type, sym)) + return 0; +#endif +#endif + if (!arch_kprobe_get_kallsym(&symnum, value, type, sym)) + return 0; + return -ERANGE; +} + int __init __weak arch_populate_kprobe_blacklist(void) { return 0; -- 2.17.1