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=-11.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 0BE14C433DF for ; Tue, 7 Jul 2020 08:23:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D1E2E206E2 for ; Tue, 7 Jul 2020 08:23:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="aCJxo4T7"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="IF5ayT+Y" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727792AbgGGIXn (ORCPT ); Tue, 7 Jul 2020 04:23:43 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:34938 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725825AbgGGIXn (ORCPT ); Tue, 7 Jul 2020 04:23:43 -0400 Date: Tue, 07 Jul 2020 08:23:38 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1594110219; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=5aJxtSkQFjlSQ/pbp1RTO99oPx6lUie8QyRW1KQh+Fw=; b=aCJxo4T7oIgCTWKVaao1ivvrzxWiTfXDtf6DG7C/YvTih73V+vWloGvQmXmtDw2nW3B/r6 hjNs0YNLuFUMlTq+fMkp60C3lg0mjlQZPdaowgKFd3ECxRP6SbEdzR1tN58nGKl5CEuw6u ZhTisoFiCzZOJWToC/B/D1RFNr1GivnCEkEzVfEc8BR8uWpeY+TMIF6EuSi9Nv07xuTSHq FEmSnPSguzPiCyTi8YgLjSqpLPgNXZz+WejVmMcjCCfmosykcgbHIwzm343h+l4lmQ+PrP q+vZOZVqFtHZw6EorSPpCHqTB5ReQ7FNQvEoko4tvFsAzz6f7K3b6iyclXrg/g== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1594110219; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=5aJxtSkQFjlSQ/pbp1RTO99oPx6lUie8QyRW1KQh+Fw=; b=IF5ayT+Yr8oxbQitpstt72icOq4JIioW4izk90rKQZSonUnxJqBj6eae8NGTXqxUMpHP/U +TD1uwqSk2nGd3CQ== From: "tip-bot2 for Andy Lutomirski" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/entry] x86/entry: Rename idtentry_enter/exit_cond_rcu() to idtentry_enter/exit() Cc: Andy Lutomirski , Thomas Gleixner , "Peter Zijlstra (Intel)" , x86 , LKML In-Reply-To: <247fc67685263e0b673e1d7f808182d28ff80359.1593795633.git.luto@kernel.org> References: <247fc67685263e0b673e1d7f808182d28ff80359.1593795633.git.luto@kernel.org> MIME-Version: 1.0 Message-ID: <159411021855.4006.13113751062324360868.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit 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 x86/entry branch of tip: Commit-ID: b037b09b9058d84882fa2c4db3806433e2b0f912 Gitweb: https://git.kernel.org/tip/b037b09b9058d84882fa2c4db3806433e2b0f912 Author: Andy Lutomirski AuthorDate: Fri, 03 Jul 2020 10:02:58 -07:00 Committer: Thomas Gleixner CommitterDate: Mon, 06 Jul 2020 21:15:52 +02:00 x86/entry: Rename idtentry_enter/exit_cond_rcu() to idtentry_enter/exit() They were originally called _cond_rcu because they were special versions with conditional RCU handling. Now they're the standard entry and exit path, so the _cond_rcu part is just confusing. Drop it. Also change the signature to make them more extensible and more foolproof. No functional change -- it's pure refactoring. Signed-off-by: Andy Lutomirski Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/247fc67685263e0b673e1d7f808182d28ff80359.1593795633.git.luto@kernel.org --- arch/x86/entry/common.c | 50 +++++++++++++++++--------------- arch/x86/include/asm/idtentry.h | 28 ++++++++++-------- arch/x86/kernel/kvm.c | 6 ++-- arch/x86/kernel/traps.c | 6 ++-- arch/x86/mm/fault.c | 6 ++-- 5 files changed, 53 insertions(+), 43 deletions(-) diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index e83b3f1..0521546 100644 --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -559,8 +559,7 @@ SYSCALL_DEFINE0(ni_syscall) } /** - * idtentry_enter_cond_rcu - Handle state tracking on idtentry with conditional - * RCU handling + * idtentry_enter - Handle state tracking on ordinary idtentries * @regs: Pointer to pt_regs of interrupted context * * Invokes: @@ -572,6 +571,9 @@ SYSCALL_DEFINE0(ni_syscall) * - The hardirq tracer to keep the state consistent as low level ASM * entry disabled interrupts. * + * As a precondition, this requires that the entry came from user mode, + * idle, or a kernel context in which RCU is watching. + * * For kernel mode entries RCU handling is done conditional. If RCU is * watching then the only RCU requirement is to check whether the tick has * to be restarted. If RCU is not watching then rcu_irq_enter() has to be @@ -585,18 +587,21 @@ SYSCALL_DEFINE0(ni_syscall) * establish the proper context for NOHZ_FULL. Otherwise scheduling on exit * would not be possible. * - * Returns: True if RCU has been adjusted on a kernel entry - * False otherwise + * Returns: An opaque object that must be passed to idtentry_exit() * - * The return value must be fed into the rcu_exit argument of - * idtentry_exit_cond_rcu(). + * The return value must be fed into the state argument of + * idtentry_exit(). */ -bool noinstr idtentry_enter_cond_rcu(struct pt_regs *regs) +idtentry_state_t noinstr idtentry_enter(struct pt_regs *regs) { + idtentry_state_t ret = { + .exit_rcu = false, + }; + if (user_mode(regs)) { check_user_regs(regs); enter_from_user_mode(); - return false; + return ret; } /* @@ -634,7 +639,8 @@ bool noinstr idtentry_enter_cond_rcu(struct pt_regs *regs) trace_hardirqs_off_finish(); instrumentation_end(); - return true; + ret.exit_rcu = true; + return ret; } /* @@ -649,7 +655,7 @@ bool noinstr idtentry_enter_cond_rcu(struct pt_regs *regs) trace_hardirqs_off(); instrumentation_end(); - return false; + return ret; } static void idtentry_exit_cond_resched(struct pt_regs *regs, bool may_sched) @@ -667,10 +673,9 @@ static void idtentry_exit_cond_resched(struct pt_regs *regs, bool may_sched) } /** - * idtentry_exit_cond_rcu - Handle return from exception with conditional RCU - * handling + * idtentry_exit - Handle return from exception that used idtentry_enter() * @regs: Pointer to pt_regs (exception entry regs) - * @rcu_exit: Invoke rcu_irq_exit() if true + * @state: Return value from matching call to idtentry_enter() * * Depending on the return target (kernel/user) this runs the necessary * preemption and work checks if possible and reguired and returns to @@ -679,10 +684,10 @@ static void idtentry_exit_cond_resched(struct pt_regs *regs, bool may_sched) * This is the last action before returning to the low level ASM code which * just needs to return to the appropriate context. * - * Counterpart to idtentry_enter_cond_rcu(). The return value of the entry - * function must be fed into the @rcu_exit argument. + * Counterpart to idtentry_enter(). The return value of the entry + * function must be fed into the @state argument. */ -void noinstr idtentry_exit_cond_rcu(struct pt_regs *regs, bool rcu_exit) +void noinstr idtentry_exit(struct pt_regs *regs, idtentry_state_t state) { lockdep_assert_irqs_disabled(); @@ -695,7 +700,7 @@ void noinstr idtentry_exit_cond_rcu(struct pt_regs *regs, bool rcu_exit) * carefully and needs the same ordering of lockdep/tracing * and RCU as the return to user mode path. */ - if (rcu_exit) { + if (state.exit_rcu) { instrumentation_begin(); /* Tell the tracer that IRET will enable interrupts */ trace_hardirqs_on_prepare(); @@ -714,7 +719,7 @@ void noinstr idtentry_exit_cond_rcu(struct pt_regs *regs, bool rcu_exit) * IRQ flags state is correct already. Just tell RCU if it * was not watching on entry. */ - if (rcu_exit) + if (state.exit_rcu) rcu_irq_exit(); } } @@ -800,9 +805,10 @@ static void __xen_pv_evtchn_do_upcall(void) __visible noinstr void xen_pv_evtchn_do_upcall(struct pt_regs *regs) { struct pt_regs *old_regs; - bool inhcall, rcu_exit; + bool inhcall; + idtentry_state_t state; - rcu_exit = idtentry_enter_cond_rcu(regs); + state = idtentry_enter(regs); old_regs = set_irq_regs(regs); instrumentation_begin(); @@ -812,13 +818,13 @@ __visible noinstr void xen_pv_evtchn_do_upcall(struct pt_regs *regs) set_irq_regs(old_regs); inhcall = get_and_clear_inhcall(); - if (inhcall && !WARN_ON_ONCE(rcu_exit)) { + if (inhcall && !WARN_ON_ONCE(state.exit_rcu)) { instrumentation_begin(); idtentry_exit_cond_resched(regs, true); instrumentation_end(); restore_inhcall(inhcall); } else { - idtentry_exit_cond_rcu(regs, rcu_exit); + idtentry_exit(regs, state); } } #endif /* CONFIG_XEN_PV */ diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h index eeac6dc..7227225 100644 --- a/arch/x86/include/asm/idtentry.h +++ b/arch/x86/include/asm/idtentry.h @@ -13,8 +13,12 @@ void idtentry_enter_user(struct pt_regs *regs); void idtentry_exit_user(struct pt_regs *regs); -bool idtentry_enter_cond_rcu(struct pt_regs *regs); -void idtentry_exit_cond_rcu(struct pt_regs *regs, bool rcu_exit); +typedef struct idtentry_state { + bool exit_rcu; +} idtentry_state_t; + +idtentry_state_t idtentry_enter(struct pt_regs *regs); +void idtentry_exit(struct pt_regs *regs, idtentry_state_t state); /** * DECLARE_IDTENTRY - Declare functions for simple IDT entry points @@ -54,12 +58,12 @@ static __always_inline void __##func(struct pt_regs *regs); \ \ __visible noinstr void func(struct pt_regs *regs) \ { \ - bool rcu_exit = idtentry_enter_cond_rcu(regs); \ + idtentry_state_t state = idtentry_enter(regs); \ \ instrumentation_begin(); \ __##func (regs); \ instrumentation_end(); \ - idtentry_exit_cond_rcu(regs, rcu_exit); \ + idtentry_exit(regs, state); \ } \ \ static __always_inline void __##func(struct pt_regs *regs) @@ -101,12 +105,12 @@ static __always_inline void __##func(struct pt_regs *regs, \ __visible noinstr void func(struct pt_regs *regs, \ unsigned long error_code) \ { \ - bool rcu_exit = idtentry_enter_cond_rcu(regs); \ + idtentry_state_t state = idtentry_enter(regs); \ \ instrumentation_begin(); \ __##func (regs, error_code); \ instrumentation_end(); \ - idtentry_exit_cond_rcu(regs, rcu_exit); \ + idtentry_exit(regs, state); \ } \ \ static __always_inline void __##func(struct pt_regs *regs, \ @@ -199,7 +203,7 @@ static __always_inline void __##func(struct pt_regs *regs, u8 vector); \ __visible noinstr void func(struct pt_regs *regs, \ unsigned long error_code) \ { \ - bool rcu_exit = idtentry_enter_cond_rcu(regs); \ + idtentry_state_t state = idtentry_enter(regs); \ \ instrumentation_begin(); \ irq_enter_rcu(); \ @@ -207,7 +211,7 @@ __visible noinstr void func(struct pt_regs *regs, \ __##func (regs, (u8)error_code); \ irq_exit_rcu(); \ instrumentation_end(); \ - idtentry_exit_cond_rcu(regs, rcu_exit); \ + idtentry_exit(regs, state); \ } \ \ static __always_inline void __##func(struct pt_regs *regs, u8 vector) @@ -241,7 +245,7 @@ static void __##func(struct pt_regs *regs); \ \ __visible noinstr void func(struct pt_regs *regs) \ { \ - bool rcu_exit = idtentry_enter_cond_rcu(regs); \ + idtentry_state_t state = idtentry_enter(regs); \ \ instrumentation_begin(); \ irq_enter_rcu(); \ @@ -249,7 +253,7 @@ __visible noinstr void func(struct pt_regs *regs) \ run_on_irqstack_cond(__##func, regs, regs); \ irq_exit_rcu(); \ instrumentation_end(); \ - idtentry_exit_cond_rcu(regs, rcu_exit); \ + idtentry_exit(regs, state); \ } \ \ static noinline void __##func(struct pt_regs *regs) @@ -270,7 +274,7 @@ static __always_inline void __##func(struct pt_regs *regs); \ \ __visible noinstr void func(struct pt_regs *regs) \ { \ - bool rcu_exit = idtentry_enter_cond_rcu(regs); \ + idtentry_state_t state = idtentry_enter(regs); \ \ instrumentation_begin(); \ __irq_enter_raw(); \ @@ -278,7 +282,7 @@ __visible noinstr void func(struct pt_regs *regs) \ __##func (regs); \ __irq_exit_raw(); \ instrumentation_end(); \ - idtentry_exit_cond_rcu(regs, rcu_exit); \ + idtentry_exit(regs, state); \ } \ \ static __always_inline void __##func(struct pt_regs *regs) diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index df63786..3f78482 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -233,7 +233,7 @@ EXPORT_SYMBOL_GPL(kvm_read_and_reset_apf_flags); noinstr bool __kvm_handle_async_pf(struct pt_regs *regs, u32 token) { u32 reason = kvm_read_and_reset_apf_flags(); - bool rcu_exit; + idtentry_state_t state; switch (reason) { case KVM_PV_REASON_PAGE_NOT_PRESENT: @@ -243,7 +243,7 @@ noinstr bool __kvm_handle_async_pf(struct pt_regs *regs, u32 token) return false; } - rcu_exit = idtentry_enter_cond_rcu(regs); + state = idtentry_enter(regs); instrumentation_begin(); /* @@ -264,7 +264,7 @@ noinstr bool __kvm_handle_async_pf(struct pt_regs *regs, u32 token) } instrumentation_end(); - idtentry_exit_cond_rcu(regs, rcu_exit); + idtentry_exit(regs, state); return true; } diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index b038695..4627f82 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -245,7 +245,7 @@ static noinstr bool handle_bug(struct pt_regs *regs) DEFINE_IDTENTRY_RAW(exc_invalid_op) { - bool rcu_exit; + idtentry_state_t state; /* * We use UD2 as a short encoding for 'CALL __WARN', as such @@ -255,11 +255,11 @@ DEFINE_IDTENTRY_RAW(exc_invalid_op) if (!user_mode(regs) && handle_bug(regs)) return; - rcu_exit = idtentry_enter_cond_rcu(regs); + state = idtentry_enter(regs); instrumentation_begin(); handle_invalid_op(regs); instrumentation_end(); - idtentry_exit_cond_rcu(regs, rcu_exit); + idtentry_exit(regs, state); } DEFINE_IDTENTRY(exc_coproc_segment_overrun) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 1ead568..5e41949 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -1377,7 +1377,7 @@ handle_page_fault(struct pt_regs *regs, unsigned long error_code, DEFINE_IDTENTRY_RAW_ERRORCODE(exc_page_fault) { unsigned long address = read_cr2(); - bool rcu_exit; + idtentry_state_t state; prefetchw(¤t->mm->mmap_lock); @@ -1412,11 +1412,11 @@ DEFINE_IDTENTRY_RAW_ERRORCODE(exc_page_fault) * code reenabled RCU to avoid subsequent wreckage which helps * debugability. */ - rcu_exit = idtentry_enter_cond_rcu(regs); + state = idtentry_enter(regs); instrumentation_begin(); handle_page_fault(regs, error_code, address); instrumentation_end(); - idtentry_exit_cond_rcu(regs, rcu_exit); + idtentry_exit(regs, state); }