linux-kernel - [PATCH 5.4-rc1 BUILD FIX] s390: mark __cpacf_query() as __always

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Date:   Tue, 1 Oct 2019 22:08:01 +0200 (CEST)
From:   Jiri Kosina <jikos@...nel.org>
To:     Heiko Carstens <heiko.carstens@...ibm.com>,
        Vasily Gorbik <gor@...ux.ibm.com>,
        Christian Borntraeger <borntraeger@...ibm.com>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>
cc:     linux-s390@...r.kernel.org, Michal Kubecek <mkubecek@...e.cz>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 5.4-rc1 BUILD FIX] s390: mark __cpacf_query() as
 __always_inline

arch/s390/kvm/kvm-s390.c calls on several places __cpacf_query() directly, 
which makes it impossible to meet the "i" constraint for the asm operands 
(opcode in this case).

As we are now force-enabling CONFIG_OPTIMIZE_INLINING on all 
architectures, this causes a build failure on s390:

   In file included from arch/s390/kvm/kvm-s390.c:44:
   ./arch/s390/include/asm/cpacf.h: In function '__cpacf_query':
   ./arch/s390/include/asm/cpacf.h:179:2: warning: asm operand 3 probably doesn't match constraints
     179 |  asm volatile(
         |  ^~~
   ./arch/s390/include/asm/cpacf.h:179:2: error: impossible constraint in 'asm'

Mark __cpacf_query() as __always_inline in order to fix that, analogically 
how we fixes __cpacf_check_opcode(), cpacf_query_func() and scpacf_query() 
already.

Reported-and-tested-by: Michal Kubecek <mkubecek@...e.cz>
Fixes: d83623c5eab2 ("s390: mark __cpacf_check_opcode() and cpacf_query_func() as __always_inline")
Fixes: e60fb8bf68d4 ("s390/cpacf: mark scpacf_query() as __always_inline")
Fixes: ac7c3e4ff401 ("compiler: enable CONFIG_OPTIMIZE_INLINING forcibly")
Fixes: 9012d011660e ("compiler: allow all arches to enable CONFIG_OPTIMIZE_INLINING")
Signed-off-by: Jiri Kosina <jkosina@...e.cz>
---

I am wondering how is it possible that none of the build-testing 
infrastructure we have running against linux-next caught this? Not enough 
non-x86 coverage?

 arch/s390/include/asm/cpacf.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/s390/include/asm/cpacf.h b/arch/s390/include/asm/cpacf.h
index a092f63aac6a..c0f3bfeddcbe 100644
--- a/arch/s390/include/asm/cpacf.h
+++ b/arch/s390/include/asm/cpacf.h
@@ -171,7 +171,7 @@ typedef struct { unsigned char bytes[16]; } cpacf_mask_t;
  *
  * Returns 1 if @func is available for @opcode, 0 otherwise
  */
-static inline void __cpacf_query(unsigned int opcode, cpacf_mask_t *mask)
+static __always_inline void __cpacf_query(unsigned int opcode, cpacf_mask_t *mask)
 {
 	register unsigned long r0 asm("0") = 0;	/* query function */
 	register unsigned long r1 asm("1") = (unsigned long) mask;

-- 
Jiri Kosina
SUSE Labs