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From:   Nicolai Stange <nstange@suse.de>
To:     Thomas Gleixner <tglx@linutronix.de>
Cc:     Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Juergen Gross <jgross@suse.com>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        David Woodhouse <dwmw@amazon.co.uk>, x86@kernel.org,
        xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org,
        Nicolai Stange <nstange@suse.de>
Subject: [PATCH] xen: x86: make asm/xen/events.h include xen/xen.h
Date:   Sun, 23 Sep 2018 19:38:02 +0200
Message-Id: <20180923173802.10339-1-nstange@suse.de>
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Sender: linux-kernel-owner@vger.kernel.org
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arch/x86/include/asm/xen/events.h references xen_hvm_domain() from the
inlined xen_support_evtchn_rebind().

xen_hvm_domain() gets #defined in include/xen/xen.h and
arch/x86/include/asm/xen/events.h doesn't include that.

On current Linus' tree, everything works fine though, because of the
following inclusion chain

  include/xen/events.h
   arch/x86/include/asm/xen/hypercall.h
    arch/x86/include/asm/pgtable.h
     arch/x86/include/asm/fixmap.h
      arch/x86/include/asm/acpi.h
       arch/x86/include/asm/realmode.h
        arch/x86/include/asm/io.h
         include/xen/xen.h
   asm/xen/events.h

which has been established in commit f991376e444a ("x86/mm: Correct fixmap
header usage on adaptable MODULES_END") resp. commit ef37bc361442
("x86/headers: Simplify asm/fixmap.h inclusion into asm/pgtable*.h").

Stable 4.9 lacks both of these and backporting them wouldn't really make
sense.

In consequence, the backport of commit 447ae3166702 ("x86: Don't include
linux/irq.h from asm/hardirq.h") to stable 4.9 broke compilation with
errors like

  In file included from include/xen/events.h:11:0,
                   from arch/x86/xen/irq.c:9:
  arch/x86/include/asm/xen/events.h: In function
    ‘xen_support_evtchn_rebind’:
  arch/x86/include/asm/xen/events.h:31:2: error: implicit declaration of
    function ‘xen_hvm_domain’ [-Werror=implicit-function-declaration]
    return (!xen_hvm_domain() || xen_have_vector_callback);
    ^

Facilitate backporting to the stable trees by making
arch/x86/include/asm/xen/events.h include xen/xen.h.

Fixes: 447ae3166702 ("x86: Don't include linux/irq.h from asm/hardirq.h")
Cc: <stable@vger.kernel.org> # 4.9.x
Signed-off-by: Nicolai Stange <nstange@suse.de>
---
 arch/x86/include/asm/xen/events.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/include/asm/xen/events.h b/arch/x86/include/asm/xen/events.h
index d383140e1dc8..068d9b067c83 100644
--- a/arch/x86/include/asm/xen/events.h
+++ b/arch/x86/include/asm/xen/events.h
@@ -2,6 +2,8 @@
 #ifndef _ASM_X86_XEN_EVENTS_H
 #define _ASM_X86_XEN_EVENTS_H
 
+#include <xen/xen.h>
+
 enum ipi_vector {
 	XEN_RESCHEDULE_VECTOR,
 	XEN_CALL_FUNCTION_VECTOR,
-- 
2.13.7