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 D6A81C47254 for ; Tue, 5 May 2020 14:16:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B7AA820838 for ; Tue, 5 May 2020 14:16:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729451AbgEEOQ0 (ORCPT ); Tue, 5 May 2020 10:16:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49116 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1730071AbgEEOQU (ORCPT ); Tue, 5 May 2020 10:16:20 -0400 Received: from Galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 121A3C061A0F for ; Tue, 5 May 2020 07:16:20 -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 1jVyMc-00022P-4z; Tue, 05 May 2020 16:16:02 +0200 Received: from nanos.tec.linutronix.de (localhost [IPv6:::1]) by nanos.tec.linutronix.de (Postfix) with ESMTP id 969F6FFC8D; Tue, 5 May 2020 16:16:01 +0200 (CEST) Message-Id: <20200505135314.716186134@linutronix.de> User-Agent: quilt/0.65 Date: Tue, 05 May 2020 15:49:40 +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 Subject: [patch V4 part 4 14/24] x86/nmi: Protect NMI entry against instrumentation 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 Mark all functions in the fragile code parts noinstr or force inlining so they can't be instrumented. Signed-off-by: Thomas Gleixner --- arch/x86/include/asm/desc.h | 8 ++++---- arch/x86/kernel/cpu/common.c | 6 ++---- arch/x86/kernel/nmi.c | 10 ++++++---- 3 files changed, 12 insertions(+), 12 deletions(-) --- a/arch/x86/include/asm/desc.h +++ b/arch/x86/include/asm/desc.h @@ -214,7 +214,7 @@ static inline void native_load_gdt(const asm volatile("lgdt %0"::"m" (*dtr)); } -static inline void native_load_idt(const struct desc_ptr *dtr) +static __always_inline void native_load_idt(const struct desc_ptr *dtr) { asm volatile("lidt %0"::"m" (*dtr)); } @@ -393,7 +393,7 @@ extern unsigned long system_vectors[]; #ifdef CONFIG_X86_64 DECLARE_PER_CPU(u32, debug_idt_ctr); -static inline bool is_debug_idt_enabled(void) +static __always_inline bool is_debug_idt_enabled(void) { if (this_cpu_read(debug_idt_ctr)) return true; @@ -401,7 +401,7 @@ static inline bool is_debug_idt_enabled( return false; } -static inline void load_debug_idt(void) +static __always_inline void load_debug_idt(void) { load_idt((const struct desc_ptr *)&debug_idt_descr); } @@ -423,7 +423,7 @@ static inline void load_debug_idt(void) * that doesn't need to disable interrupts, as nothing should be * bothering the CPU then. */ -static inline void load_current_idt(void) +static __always_inline void load_current_idt(void) { if (is_debug_idt_enabled()) load_debug_idt(); --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1692,21 +1692,19 @@ void syscall_init(void) DEFINE_PER_CPU(int, debug_stack_usage); DEFINE_PER_CPU(u32, debug_idt_ctr); -void debug_stack_set_zero(void) +noinstr void debug_stack_set_zero(void) { this_cpu_inc(debug_idt_ctr); load_current_idt(); } -NOKPROBE_SYMBOL(debug_stack_set_zero); -void debug_stack_reset(void) +noinstr void debug_stack_reset(void) { if (WARN_ON(!this_cpu_read(debug_idt_ctr))) return; if (this_cpu_dec_return(debug_idt_ctr) == 0) load_current_idt(); } -NOKPROBE_SYMBOL(debug_stack_reset); #else /* CONFIG_X86_64 */ --- a/arch/x86/kernel/nmi.c +++ b/arch/x86/kernel/nmi.c @@ -307,7 +307,7 @@ NOKPROBE_SYMBOL(unknown_nmi_error); static DEFINE_PER_CPU(bool, swallow_nmi); static DEFINE_PER_CPU(unsigned long, last_nmi_rip); -static void default_do_nmi(struct pt_regs *regs) +static noinstr void default_do_nmi(struct pt_regs *regs) { unsigned char reason = 0; int handled; @@ -333,6 +333,7 @@ static void default_do_nmi(struct pt_reg __this_cpu_write(last_nmi_rip, regs->ip); + instr_begin(); handled = nmi_handle(NMI_LOCAL, regs); __this_cpu_add(nmi_stats.normal, handled); if (handled) { @@ -346,6 +347,7 @@ static void default_do_nmi(struct pt_reg */ if (handled > 1) __this_cpu_write(swallow_nmi, true); + instr_end(); return; } @@ -378,6 +380,7 @@ static void default_do_nmi(struct pt_reg #endif __this_cpu_add(nmi_stats.external, 1); raw_spin_unlock(&nmi_reason_lock); + instr_end(); return; } raw_spin_unlock(&nmi_reason_lock); @@ -416,8 +419,8 @@ static void default_do_nmi(struct pt_reg __this_cpu_add(nmi_stats.swallow, 1); else unknown_nmi_error(reason, regs); + instr_end(); } -NOKPROBE_SYMBOL(default_do_nmi); /* * NMIs can page fault or hit breakpoints which will cause it to lose @@ -489,7 +492,7 @@ static DEFINE_PER_CPU(unsigned long, nmi */ static DEFINE_PER_CPU(int, update_debug_stack); -static bool notrace is_debug_stack(unsigned long addr) +static noinstr bool is_debug_stack(unsigned long addr) { struct cea_exception_stacks *cs = __this_cpu_read(cea_exception_stacks); unsigned long top = CEA_ESTACK_TOP(cs, DB); @@ -504,7 +507,6 @@ static bool notrace is_debug_stack(unsig */ return addr >= bot && addr < top; } -NOKPROBE_SYMBOL(is_debug_stack); #endif DEFINE_IDTENTRY_NMI(exc_nmi)