All of lore.kernel.org
 help / color / mirror / Atom feed
From: "tip-bot2 for Peter Zijlstra" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>, x86 <x86@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: [tip: x86/entry] x86/entry: Clarify irq_{enter,exit}_rcu()
Date: Sat, 30 May 2020 09:57:18 -0000	[thread overview]
Message-ID: <159083263842.17951.2162910976893497225.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20200529213321.359433429@infradead.org>

The following commit has been merged into the x86/entry branch of tip:

Commit-ID:     b614345f52bcde8299a53132f5e48a9eb5a1f320
Gitweb:        https://git.kernel.org/tip/b614345f52bcde8299a53132f5e48a9eb5a1f320
Author:        Peter Zijlstra <peterz@infradead.org>
AuthorDate:    Fri, 29 May 2020 23:27:39 +02:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Sat, 30 May 2020 10:00:10 +02:00

x86/entry: Clarify irq_{enter,exit}_rcu()

Because:

  irq_enter_rcu() includes lockdep_hardirq_enter()
  irq_exit_rcu() does *NOT* include lockdep_hardirq_exit()

Which resulted in two 'stray' lockdep_hardirq_exit() calls in
idtentry.h, and me spending a long time trying to find the matching
enter calls.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200529213321.359433429@infradead.org

---
 arch/x86/include/asm/idtentry.h |  2 --
 kernel/softirq.c                | 19 +++++++++++++------
 2 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index d214a30..f8e2737 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -206,7 +206,6 @@ __visible noinstr void func(struct pt_regs *regs,			\
 	kvm_set_cpu_l1tf_flush_l1d();					\
 	__##func (regs, (u8)error_code);				\
 	irq_exit_rcu();							\
-	lockdep_hardirq_exit();						\
 	instrumentation_end();						\
 	idtentry_exit_cond_rcu(regs, rcu_exit);				\
 }									\
@@ -249,7 +248,6 @@ __visible noinstr void func(struct pt_regs *regs)			\
 	kvm_set_cpu_l1tf_flush_l1d();					\
 	run_on_irqstack_cond(__##func, regs, regs);			\
 	irq_exit_rcu();							\
-	lockdep_hardirq_exit();						\
 	instrumentation_end();						\
 	idtentry_exit_cond_rcu(regs, rcu_exit);				\
 }									\
diff --git a/kernel/softirq.c b/kernel/softirq.c
index beb8e3a..a3eb6eb 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -404,12 +404,7 @@ static inline void tick_irq_exit(void)
 #endif
 }
 
-/**
- * irq_exit_rcu() - Exit an interrupt context without updating RCU
- *
- * Also processes softirqs if needed and possible.
- */
-void irq_exit_rcu(void)
+static inline void __irq_exit_rcu(void)
 {
 #ifndef __ARCH_IRQ_EXIT_IRQS_DISABLED
 	local_irq_disable();
@@ -425,6 +420,18 @@ void irq_exit_rcu(void)
 }
 
 /**
+ * irq_exit_rcu() - Exit an interrupt context without updating RCU
+ *
+ * Also processes softirqs if needed and possible.
+ */
+void irq_exit_rcu(void)
+{
+	__irq_exit_rcu();
+	 /* must be last! */
+	lockdep_hardirq_exit();
+}
+
+/**
  * irq_exit - Exit an interrupt context, update RCU and lockdep
  *
  * Also processes softirqs if needed and possible.

  reply	other threads:[~2020-05-30  9:58 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-29 21:27 [PATCH 00/14] x86/entry: disallow #DB more and x86/entry lockdep/nmi Peter Zijlstra
2020-05-29 21:27 ` [PATCH 01/14] x86/hw_breakpoint: Add within_area() to check data breakpoints Peter Zijlstra
2020-05-29 21:27 ` [PATCH 02/14] x86/hw_breakpoint: Prevent data breakpoints on direct GDT Peter Zijlstra
2020-05-30 12:45   ` Andrew Cooper
2020-05-30 15:15     ` Lai Jiangshan
2020-05-29 21:27 ` [PATCH 03/14] x86/hw_breakpoint: Prevent data breakpoints on per_cpu cpu_tss_rw Peter Zijlstra
2020-05-29 21:27 ` [PATCH 04/14] x86/hw_breakpoint: Prevent data breakpoints on user_pcid_flush_mask Peter Zijlstra
2020-05-29 21:27 ` [PATCH 05/14] x86/entry: Introduce local_db_{save,restore}() Peter Zijlstra
2020-05-30  9:57   ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-05-29 21:27 ` [PATCH 06/14] x86/entry, nmi: Disable #DB Peter Zijlstra
2020-05-30  9:57   ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-05-29 21:27 ` [PATCH 07/14] x86/entry, mce: Disallow #DB during #MC Peter Zijlstra
2020-05-30  9:57   ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-05-29 21:27 ` [PATCH 08/14] x86/entry: Optimize local_db_save() for virt Peter Zijlstra
2020-05-30  9:57   ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-06-03  1:17   ` [PATCH 08/14] " Sean Christopherson
2020-05-29 21:27 ` [PATCH 09/14] x86/entry: Remove debug IDT frobbing Peter Zijlstra
2020-05-30  9:57   ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-05-29 21:27 ` [PATCH 10/14] x86/entry: Remove DBn stacks Peter Zijlstra
2020-05-30  9:57   ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-05-29 21:27 ` [PATCH 11/14] x86/entry: Clarify irq_{enter,exit}_rcu() Peter Zijlstra
2020-05-30  9:57   ` tip-bot2 for Peter Zijlstra [this message]
2020-06-02 14:42   ` Qian Cai
2020-06-02 14:42     ` Qian Cai
2020-06-02 15:05     ` Peter Zijlstra
2020-06-02 15:05       ` Peter Zijlstra
2020-06-02 18:47       ` Qian Cai
2020-06-02 18:47         ` Qian Cai
2020-06-03 17:50       ` [tip: x86/entry] x86/entry: Use __irq_exit_rcu() in irq_exit() tip-bot2 for Peter Zijlstra
2020-05-29 21:27 ` [PATCH 12/14] x86/entry: Rename trace_hardirqs_off_prepare() Peter Zijlstra
2020-05-30  9:57   ` [tip: x86/entry] " tip-bot2 for Peter Zijlstra
2020-05-29 21:27 ` [PATCH 13/14] lockdep: Prepare for NMI IRQ state tracking Peter Zijlstra
2020-05-29 22:14   ` Steven Rostedt
2020-05-29 22:25     ` Peter Zijlstra
2020-05-29 22:28       ` Steven Rostedt
2020-05-29 22:33       ` Peter Zijlstra
2020-06-02 20:00       ` Peter Zijlstra
2020-05-29 21:27 ` [PATCH 14/14] x86/entry: Fix NMI vs " Peter Zijlstra

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=159083263842.17951.2162910976893497225.tip-bot2@tip-bot2 \
    --to=tip-bot2@linutronix.de \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-tip-commits@vger.kernel.org \
    --cc=peterz@infradead.org \
    --cc=tglx@linutronix.de \
    --cc=x86@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.