linux-kernel - [tip:x86/debug] x86/kvm: Add output operand in vmx_handle_external

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Date:	Wed, 24 Feb 2016 21:53:09 -0800
From:	tip-bot for Chris J Arges <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	tglx@...utronix.de, linux-kernel@...r.kernel.org,
	peterz@...radead.org, chris.j.arges@...onical.com,
	jpoimboe@...hat.com, mingo@...nel.org,
	torvalds@...ux-foundation.org, hpa@...or.com
Subject: [tip:x86/debug] x86/kvm: Add output operand in
 vmx_handle_external_intr inline asm

Commit-ID:  3f62de5f6f369b67b7ac709e3c942c9130d2c51a
Gitweb:     http://git.kernel.org/tip/3f62de5f6f369b67b7ac709e3c942c9130d2c51a
Author:     Chris J Arges <chris.j.arges@...onical.com>
AuthorDate: Fri, 22 Jan 2016 15:44:38 -0600
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Wed, 24 Feb 2016 08:35:44 +0100

x86/kvm: Add output operand in vmx_handle_external_intr inline asm

Stacktool generates the following warning:
  stacktool: arch/x86/kvm/vmx.o: vmx_handle_external_intr()+0x67: call without frame pointer save/setup

By adding the stackpointer as an output operand, this patch ensures that a
stack frame is created when CONFIG_FRAME_POINTER is enabled for the inline
assmebly statement.

Signed-off-by: Chris J Arges <chris.j.arges@...onical.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: gleb@...nel.org
Cc: kvm@...r.kernel.org
Cc: live-patching@...r.kernel.org
Cc: pbonzini@...hat.com
Link: http://lkml.kernel.org/r/1453499078-9330-3-git-send-email-chris.j.arges@canonical.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/kvm/vmx.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e2951b6..e153522 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8356,6 +8356,7 @@ static void vmx_complete_atomic_exit(struct vcpu_vmx *vmx)
 static void vmx_handle_external_intr(struct kvm_vcpu *vcpu)
 {
 	u32 exit_intr_info = vmcs_read32(VM_EXIT_INTR_INFO);
+	register void *__sp asm(_ASM_SP);
 
 	/*
 	 * If external interrupt exists, IF bit is set in rflags/eflags on the
@@ -8388,8 +8389,9 @@ static void vmx_handle_external_intr(struct kvm_vcpu *vcpu)
 			"call *%[entry]\n\t"
 			:
 #ifdef CONFIG_X86_64
-			[sp]"=&r"(tmp)
+			[sp]"=&r"(tmp),
 #endif
+			"+r"(__sp)
 			:
 			[entry]"r"(entry),
 			[ss]"i"(__KERNEL_DS),