linux-kernel - [RESEND] [RFC][PATCH X86_32 1/2]: Call do_notify

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Message-ID: <20111025141812.GA21225@linux.vnet.ibm.com>
Date:	Tue, 25 Oct 2011 19:48:12 +0530
From:	Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
To:	Peter Zijlstra <peterz@...radead.org>,
	"H. Peter Anvin" <hpa@...or.com>
Cc:	Steven Rostedt <rostedt@...dmis.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Christoph Hellwig <hch@...radead.org>,
	Ananth N Mavinakayanahalli <ananth@...ibm.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Andi Kleen <andi@...stfloor.org>,
	Oleg Nesterov <oleg@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Jim Keniston <jkenisto@...ux.vnet.ibm.com>,
	Roland McGrath <roland@...k.frob.com>,
	Shuah Khan <shuah.khan@...com>, Ingo Molnar <mingo@...e.hu>,
	Alexander van Heukelum <heukelum@...tmail.fm>,
	Russell King <rmk@....linux.org.uk>,
	LKML <linux-kernel@...r.kernel.org>
Subject: [RESEND] [RFC][PATCH X86_32 1/2]: Call do_notify_resume() with
 interrupts enabled

do_notify_resume() gets called with interrupts disabled on x86_32. This
is different from the x86_64 behavior, where interrupts are enabled at
the time.

Queries on lkml on this issue hasn't yielded any clear answer. Lets make
x86_32 behave the same as x86_64, unless there is a real reason to
maintain status quo.

Please refer https://lkml.org/lkml/2011/9/27/130 for more details

A similar change was suggested in arm
	https://lkml.org/lkml/2011/8/25/231

My 32-bit machine works fine (tm) with the patch below

Signed-off-by: Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
---
 arch/x86/kernel/entry_32.S |    4 ++++
 1 files changed, 4 insertions(+)

diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index f3f6f53..22d0e21 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -625,6 +625,8 @@ work_notifysig:				# deal with pending signals and
 	movl %esp, %eax
 	jne work_notifysig_v86		# returning to kernel-space or
 					# vm86-space
+	TRACE_IRQS_ON
+	ENABLE_INTERRUPTS(CLBR_NONE)
 	xorl %edx, %edx
 	call do_notify_resume
 	jmp resume_userspace_sig
@@ -638,6 +640,8 @@ work_notifysig:				# deal with pending signals and
 #else
 	movl %esp, %eax
 #endif
+	TRACE_IRQS_ON
+	ENABLE_INTERRUPTS(CLBR_NONE)
 	xorl %edx, %edx
 	call do_notify_resume
 	jmp resume_userspace_sig

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