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=-11.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 401D5C43603 for ; Wed, 4 Dec 2019 08:34:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 04C12207DD for ; Wed, 4 Dec 2019 08:34:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727347AbfLDIeI (ORCPT ); Wed, 4 Dec 2019 03:34:08 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:56452 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727484AbfLDIeE (ORCPT ); Wed, 4 Dec 2019 03:34:04 -0500 Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1icQ6T-0005Na-Ct; Wed, 04 Dec 2019 09:33:45 +0100 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id B84471C265E; Wed, 4 Dec 2019 09:33:37 +0100 (CET) Date: Wed, 04 Dec 2019 08:33:37 -0000 From: "tip-bot2 for Peter Zijlstra" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: core/kprobes] x86/alternatives, jump_label: Provide better text_poke() batching interface Cc: Alexei Starovoitov , "Steven Rostedt (VMware)" , "Peter Zijlstra (Intel)" , Masami Hiramatsu , Daniel Bristot de Oliveira , Andy Lutomirski , Borislav Petkov , "H. Peter Anvin" , Josh Poimboeuf , Linus Torvalds , Thomas Gleixner , Ingo Molnar , x86 , LKML In-Reply-To: <20191111132457.646280715@infradead.org> References: <20191111132457.646280715@infradead.org> MIME-Version: 1.0 Message-ID: <157544841762.21853.1501350726294283123.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the core/kprobes branch of tip: Commit-ID: 18cbc8bed0c70795d2064217c89894e28eafdf04 Gitweb: https://git.kernel.org/tip/18cbc8bed0c70795d2064217c89894e28eafdf04 Author: Peter Zijlstra AuthorDate: Mon, 26 Aug 2019 13:38:58 +02:00 Committer: Ingo Molnar CommitterDate: Wed, 27 Nov 2019 07:44:24 +01:00 x86/alternatives, jump_label: Provide better text_poke() batching interface Adding another text_poke_bp_batch() user made me realize the interface is all sorts of wrong. The text poke vector should be internal to the implementation. This then results in a trivial interface: text_poke_queue() - which has the 'normal' text_poke_bp() interface text_poke_finish() - which takes no arguments and flushes any pending text_poke()s. Tested-by: Alexei Starovoitov Tested-by: Steven Rostedt (VMware) Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Masami Hiramatsu Reviewed-by: Daniel Bristot de Oliveira Acked-by: Alexei Starovoitov Cc: Andy Lutomirski Cc: Borislav Petkov Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Steven Rostedt Cc: Thomas Gleixner Link: https://lkml.kernel.org/r/20191111132457.646280715@infradead.org Signed-off-by: Ingo Molnar --- arch/x86/include/asm/text-patching.h | 15 +--- arch/x86/kernel/alternative.c | 64 +++++++++++++++-- arch/x86/kernel/jump_label.c | 99 ++++++++------------------ 3 files changed, 96 insertions(+), 82 deletions(-) diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h index ea91049..3bcd266 100644 --- a/arch/x86/include/asm/text-patching.h +++ b/arch/x86/include/asm/text-patching.h @@ -25,14 +25,6 @@ static inline void apply_paravirt(struct paravirt_patch_site *start, */ #define POKE_MAX_OPCODE_SIZE 5 -struct text_poke_loc { - void *addr; - int len; - s32 rel32; - u8 opcode; - const u8 text[POKE_MAX_OPCODE_SIZE]; -}; - extern void text_poke_early(void *addr, const void *opcode, size_t len); /* @@ -53,9 +45,10 @@ extern void *text_poke(void *addr, const void *opcode, size_t len); extern void *text_poke_kgdb(void *addr, const void *opcode, size_t len); extern int poke_int3_handler(struct pt_regs *regs); extern void text_poke_bp(void *addr, const void *opcode, size_t len, const void *emulate); -extern void text_poke_bp_batch(struct text_poke_loc *tp, unsigned int nr_entries); -extern void text_poke_loc_init(struct text_poke_loc *tp, void *addr, - const void *opcode, size_t len, const void *emulate); + +extern void text_poke_queue(void *addr, const void *opcode, size_t len, const void *emulate); +extern void text_poke_finish(void); + extern int after_bootmem; extern __ro_after_init struct mm_struct *poking_mm; extern __ro_after_init unsigned long poking_addr; diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 9ec463f..42e7f0a 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -936,6 +936,14 @@ static void do_sync_core(void *info) sync_core(); } +struct text_poke_loc { + void *addr; + int len; + s32 rel32; + u8 opcode; + const u8 text[POKE_MAX_OPCODE_SIZE]; +}; + static struct bp_patching_desc { struct text_poke_loc *vec; int nr_entries; @@ -1023,6 +1031,10 @@ int poke_int3_handler(struct pt_regs *regs) } NOKPROBE_SYMBOL(poke_int3_handler); +#define TP_VEC_MAX (PAGE_SIZE / sizeof(struct text_poke_loc)) +static struct text_poke_loc tp_vec[TP_VEC_MAX]; +static int tp_vec_nr; + /** * text_poke_bp_batch() -- update instructions on live kernel on SMP * @tp: vector of instructions to patch @@ -1044,7 +1056,7 @@ NOKPROBE_SYMBOL(poke_int3_handler); * replacing opcode * - sync cores */ -void text_poke_bp_batch(struct text_poke_loc *tp, unsigned int nr_entries) +static void text_poke_bp_batch(struct text_poke_loc *tp, unsigned int nr_entries) { unsigned char int3 = INT3_INSN_OPCODE; unsigned int i; @@ -1118,11 +1130,7 @@ void text_poke_loc_init(struct text_poke_loc *tp, void *addr, { struct insn insn; - if (!opcode) - opcode = (void *)tp->text; - else - memcpy((void *)tp->text, opcode, len); - + memcpy((void *)tp->text, opcode, len); if (!emulate) emulate = opcode; @@ -1167,6 +1175,50 @@ void text_poke_loc_init(struct text_poke_loc *tp, void *addr, } } +/* + * We hard rely on the tp_vec being ordered; ensure this is so by flushing + * early if needed. + */ +static bool tp_order_fail(void *addr) +{ + struct text_poke_loc *tp; + + if (!tp_vec_nr) + return false; + + if (!addr) /* force */ + return true; + + tp = &tp_vec[tp_vec_nr - 1]; + if ((unsigned long)tp->addr > (unsigned long)addr) + return true; + + return false; +} + +static void text_poke_flush(void *addr) +{ + if (tp_vec_nr == TP_VEC_MAX || tp_order_fail(addr)) { + text_poke_bp_batch(tp_vec, tp_vec_nr); + tp_vec_nr = 0; + } +} + +void text_poke_finish(void) +{ + text_poke_flush(NULL); +} + +void text_poke_queue(void *addr, const void *opcode, size_t len, const void *emulate) +{ + struct text_poke_loc *tp; + + text_poke_flush(addr); + + tp = &tp_vec[tp_vec_nr++]; + text_poke_loc_init(tp, addr, opcode, len, emulate); +} + /** * text_poke_bp() -- update instructions on live kernel on SMP * @addr: address to patch diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c index c1a8b9e..cf8c847 100644 --- a/arch/x86/kernel/jump_label.c +++ b/arch/x86/kernel/jump_label.c @@ -35,18 +35,19 @@ static void bug_at(unsigned char *ip, int line) BUG(); } -static void __jump_label_set_jump_code(struct jump_entry *entry, - enum jump_label_type type, - union jump_code_union *code, - int init) +static const void * +__jump_label_set_jump_code(struct jump_entry *entry, enum jump_label_type type, int init) { + static union jump_code_union code; /* relies on text_mutex */ const unsigned char default_nop[] = { STATIC_KEY_INIT_NOP }; const unsigned char *ideal_nop = ideal_nops[NOP_ATOMIC5]; const void *expect; int line; - code->jump = 0xe9; - code->offset = jump_entry_target(entry) - + lockdep_assert_held(&text_mutex); + + code.jump = JMP32_INSN_OPCODE; + code.offset = jump_entry_target(entry) - (jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE); if (init) { @@ -54,23 +55,23 @@ static void __jump_label_set_jump_code(struct jump_entry *entry, } else if (type == JUMP_LABEL_JMP) { expect = ideal_nop; line = __LINE__; } else { - expect = code->code; line = __LINE__; + expect = code.code; line = __LINE__; } if (memcmp((void *)jump_entry_code(entry), expect, JUMP_LABEL_NOP_SIZE)) bug_at((void *)jump_entry_code(entry), line); if (type == JUMP_LABEL_NOP) - memcpy(code, ideal_nop, JUMP_LABEL_NOP_SIZE); + memcpy(&code, ideal_nop, JUMP_LABEL_NOP_SIZE); + + return &code; } -static void __ref __jump_label_transform(struct jump_entry *entry, - enum jump_label_type type, - int init) +static void inline __jump_label_transform(struct jump_entry *entry, + enum jump_label_type type, + int init) { - union jump_code_union code; - - __jump_label_set_jump_code(entry, type, &code, init); + const void *opcode = __jump_label_set_jump_code(entry, type, init); /* * As long as only a single processor is running and the code is still @@ -84,31 +85,33 @@ static void __ref __jump_label_transform(struct jump_entry *entry, * always nop being the 'currently valid' instruction */ if (init || system_state == SYSTEM_BOOTING) { - text_poke_early((void *)jump_entry_code(entry), &code, + text_poke_early((void *)jump_entry_code(entry), opcode, JUMP_LABEL_NOP_SIZE); return; } - text_poke_bp((void *)jump_entry_code(entry), &code, JUMP_LABEL_NOP_SIZE, NULL); + text_poke_bp((void *)jump_entry_code(entry), opcode, JUMP_LABEL_NOP_SIZE, NULL); } -void arch_jump_label_transform(struct jump_entry *entry, - enum jump_label_type type) +static void __ref jump_label_transform(struct jump_entry *entry, + enum jump_label_type type, + int init) { mutex_lock(&text_mutex); - __jump_label_transform(entry, type, 0); + __jump_label_transform(entry, type, init); mutex_unlock(&text_mutex); } -#define TP_VEC_MAX (PAGE_SIZE / sizeof(struct text_poke_loc)) -static struct text_poke_loc tp_vec[TP_VEC_MAX]; -static int tp_vec_nr; +void arch_jump_label_transform(struct jump_entry *entry, + enum jump_label_type type) +{ + jump_label_transform(entry, type, 0); +} bool arch_jump_label_transform_queue(struct jump_entry *entry, enum jump_label_type type) { - struct text_poke_loc *tp; - void *entry_code; + const void *opcode; if (system_state == SYSTEM_BOOTING) { /* @@ -118,53 +121,19 @@ bool arch_jump_label_transform_queue(struct jump_entry *entry, return true; } - /* - * No more space in the vector, tell upper layer to apply - * the queue before continuing. - */ - if (tp_vec_nr == TP_VEC_MAX) - return false; - - tp = &tp_vec[tp_vec_nr]; - - entry_code = (void *)jump_entry_code(entry); - - /* - * The INT3 handler will do a bsearch in the queue, so we need entries - * to be sorted. We can survive an unsorted list by rejecting the entry, - * forcing the generic jump_label code to apply the queue. Warning once, - * to raise the attention to the case of an unsorted entry that is - * better not happen, because, in the worst case we will perform in the - * same way as we do without batching - with some more overhead. - */ - if (tp_vec_nr > 0) { - int prev = tp_vec_nr - 1; - struct text_poke_loc *prev_tp = &tp_vec[prev]; - - if (WARN_ON_ONCE(prev_tp->addr > entry_code)) - return false; - } - - __jump_label_set_jump_code(entry, type, - (union jump_code_union *)&tp->text, 0); - - text_poke_loc_init(tp, entry_code, NULL, JUMP_LABEL_NOP_SIZE, NULL); - - tp_vec_nr++; - + mutex_lock(&text_mutex); + opcode = __jump_label_set_jump_code(entry, type, 0); + text_poke_queue((void *)jump_entry_code(entry), + opcode, JUMP_LABEL_NOP_SIZE, NULL); + mutex_unlock(&text_mutex); return true; } void arch_jump_label_transform_apply(void) { - if (!tp_vec_nr) - return; - mutex_lock(&text_mutex); - text_poke_bp_batch(tp_vec, tp_vec_nr); + text_poke_finish(); mutex_unlock(&text_mutex); - - tp_vec_nr = 0; } static enum { @@ -193,5 +162,5 @@ __init_or_module void arch_jump_label_transform_static(struct jump_entry *entry, jlstate = JL_STATE_NO_UPDATE; } if (jlstate == JL_STATE_UPDATE) - __jump_label_transform(entry, type, 1); + jump_label_transform(entry, type, 1); }