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=-3.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 133AAC47247 for ; Tue, 5 May 2020 14:20:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ECB8420675 for ; Tue, 5 May 2020 14:20:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729088AbgEEOUQ (ORCPT ); Tue, 5 May 2020 10:20:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49044 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1729994AbgEEOQE (ORCPT ); Tue, 5 May 2020 10:16:04 -0400 Received: from Galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 133F1C061A0F for ; Tue, 5 May 2020 07:16:04 -0700 (PDT) Received: from p5de0bf0b.dip0.t-ipconnect.de ([93.224.191.11] helo=nanos.tec.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1jVyMM-0001ni-6q; Tue, 05 May 2020 16:15:46 +0200 Received: from nanos.tec.linutronix.de (localhost [IPv6:::1]) by nanos.tec.linutronix.de (Postfix) with ESMTP id 7F25CFFC8D; Tue, 5 May 2020 16:15:45 +0200 (CEST) Message-Id: <20200505135313.410702173@linutronix.de> User-Agent: quilt/0.65 Date: Tue, 05 May 2020 15:49:27 +0200 From: Thomas Gleixner To: LKML Cc: x86@kernel.org, "Paul E. McKenney" , Andy Lutomirski , Alexandre Chartre , Frederic Weisbecker , Paolo Bonzini , Sean Christopherson , Masami Hiramatsu , Petr Mladek , Steven Rostedt , Joel Fernandes , Boris Ostrovsky , Juergen Gross , Brian Gerst , Mathieu Desnoyers , Josh Poimboeuf , Will Deacon , "Peter Zijlstra (Intel)" Subject: [patch V4 part 4 01/24] x86/int3: Ensure that poke_int3_handler() is not traced References: <20200505134926.578885807@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-transfer-encoding: 8-bit 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 From: Thomas Gleixner In order to ensure poke_int3_handler() is completely self contained -- this is called while modifying other text, imagine the fun of hitting another INT3 -- ensure that everything it uses is not traced. The primary means here is to force inlining; bsearch() is notrace because all of lib/ is. Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) --- arch/x86/include/asm/ptrace.h | 2 +- arch/x86/include/asm/text-patching.h | 11 +++++++---- arch/x86/kernel/alternative.c | 13 ++++++------- 3 files changed, 14 insertions(+), 12 deletions(-) --- a/arch/x86/include/asm/ptrace.h +++ b/arch/x86/include/asm/ptrace.h @@ -123,7 +123,7 @@ static inline void regs_set_return_value * On x86_64, vm86 mode is mercifully nonexistent, and we don't need * the extra check. */ -static inline int user_mode(struct pt_regs *regs) +static __always_inline int user_mode(struct pt_regs *regs) { #ifdef CONFIG_X86_32 return ((regs->cs & SEGMENT_RPL_MASK) | (regs->flags & X86_VM_MASK)) >= USER_RPL; --- a/arch/x86/include/asm/text-patching.h +++ b/arch/x86/include/asm/text-patching.h @@ -64,7 +64,7 @@ extern void text_poke_finish(void); #define DISP32_SIZE 4 -static inline int text_opcode_size(u8 opcode) +static __always_inline int text_opcode_size(u8 opcode) { int size = 0; @@ -118,12 +118,14 @@ extern __ro_after_init struct mm_struct extern __ro_after_init unsigned long poking_addr; #ifndef CONFIG_UML_X86 -static inline void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip) +static __always_inline +void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip) { regs->ip = ip; } -static inline void int3_emulate_push(struct pt_regs *regs, unsigned long val) +static __always_inline +void int3_emulate_push(struct pt_regs *regs, unsigned long val) { /* * The int3 handler in entry_64.S adds a gap between the @@ -138,7 +140,8 @@ static inline void int3_emulate_push(str *(unsigned long *)regs->sp = val; } -static inline void int3_emulate_call(struct pt_regs *regs, unsigned long func) +static __always_inline +void int3_emulate_call(struct pt_regs *regs, unsigned long func) { int3_emulate_push(regs, regs->ip - INT3_INSN_SIZE + CALL_INSN_SIZE); int3_emulate_jmp(regs, func); --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -957,7 +957,8 @@ struct bp_patching_desc { static struct bp_patching_desc *bp_desc; -static inline struct bp_patching_desc *try_get_desc(struct bp_patching_desc **descp) +static __always_inline +struct bp_patching_desc *try_get_desc(struct bp_patching_desc **descp) { struct bp_patching_desc *desc = READ_ONCE(*descp); /* rcu_dereference */ @@ -967,18 +968,18 @@ static inline struct bp_patching_desc *t return desc; } -static inline void put_desc(struct bp_patching_desc *desc) +static __always_inline void put_desc(struct bp_patching_desc *desc) { smp_mb__before_atomic(); atomic_dec(&desc->refs); } -static inline void *text_poke_addr(struct text_poke_loc *tp) +static __always_inline void *text_poke_addr(struct text_poke_loc *tp) { return _stext + tp->rel_addr; } -static int notrace patch_cmp(const void *key, const void *elt) +static int noinstr patch_cmp(const void *key, const void *elt) { struct text_poke_loc *tp = (struct text_poke_loc *) elt; @@ -988,9 +989,8 @@ static int notrace patch_cmp(const void return 1; return 0; } -NOKPROBE_SYMBOL(patch_cmp); -int notrace poke_int3_handler(struct pt_regs *regs) +int noinstr poke_int3_handler(struct pt_regs *regs) { struct bp_patching_desc *desc; struct text_poke_loc *tp; @@ -1064,7 +1064,6 @@ int notrace poke_int3_handler(struct pt_ put_desc(desc); return ret; } -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];