Linux Virtualization - Jun 2023 - [PATCH AUTOSEL 6.3 28/30] tools/virtio: Fix arm64 ringtest compilation error

From: Rong Tao <rongtao at cestc.cn>

[ Upstream commit 57380fd1249b20ef772549af2c58ef57b21faba7 ]

Add cpu_relax() for arm64 instead of directly assert(), and add assert.h
header file. Also, add smp_wmb and smp_mb for arm64.

Compilation error as follows, avoid __always_inline undefined.

    $ make
    cc -Wall -pthread -O2 -ggdb -flto -fwhole-program -c -o ring.o ring.c
    In file included from ring.c:10:
    main.h: In function ?busy_wait?:
    main.h:99:21: warning: implicit declaration of function ?assert?
    [-Wimplicit-function-declaration]
    99 | #define cpu_relax() assert(0)
        |                     ^~~~~~
    main.h:107:17: note: in expansion of macro ?cpu_relax?
    107 |                 cpu_relax();
        |                 ^~~~~~~~~
    main.h:12:1: note: ?assert? is defined in header ?<assert.h>?; did you
    forget to ?#include <assert.h>??
    11 | #include <stdbool.h>
    +++ |+#include <assert.h>
    12 |
    main.h: At top level:
    main.h:143:23: error: expected ?;? before ?void?
    143 | static __always_inline
        |                       ^
        |                       ;
    144 | void __read_once_size(const volatile void *p, void *res, int
    size)
        | ~~~~
    main.h:158:23: error: expected ?;? before ?void?
    158 | static __always_inline void __write_once_size(volatile void *p,
    void *res, int size)
        |                       ^~~~~
        |                       ;
    make: *** [<builtin>: ring.o] Error 1

Signed-off-by: Rong Tao <rongtao at cestc.cn>
Message-Id: <tencent_F53E159DD7925174445D830DA19FACF44B07 at qq.com>
Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 tools/virtio/ringtest/main.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/tools/virtio/ringtest/main.h b/tools/virtio/ringtest/main.h
index b68920d527503..d18dd317e27f9 100644
--- a/tools/virtio/ringtest/main.h
+++ b/tools/virtio/ringtest/main.h
@@ -8,6 +8,7 @@
 #ifndef MAIN_H
 #define MAIN_H
 
+#include <assert.h>
 #include <stdbool.h>
 
 extern int param;
@@ -95,6 +96,8 @@ extern unsigned ring_size;
 #define cpu_relax() asm ("rep; nop" ::: "memory")
 #elif defined(__s390x__)
 #define cpu_relax() barrier()
+#elif defined(__aarch64__)
+#define cpu_relax() asm ("yield" ::: "memory")
 #else
 #define cpu_relax() assert(0)
 #endif
@@ -112,6 +115,8 @@ static inline void busy_wait(void)
 
 #if defined(__x86_64__) || defined(__i386__)
 #define smp_mb()     asm volatile("lock; addl $0,-132(%%rsp)" :::
"memory", "cc")
+#elif defined(__aarch64__)
+#define smp_mb()     asm volatile("dmb ish" ::: "memory")
 #else
 /*
  * Not using __ATOMIC_SEQ_CST since gcc docs say they are only synchronized
@@ -136,10 +141,16 @@ static inline void busy_wait(void)
 
 #if defined(__i386__) || defined(__x86_64__) || defined(__s390x__)
 #define smp_wmb() barrier()
+#elif defined(__aarch64__)
+#define smp_wmb() asm volatile("dmb ishst" ::: "memory")
 #else
 #define smp_wmb() smp_release()
 #endif
 
+#ifndef __always_inline
+#define __always_inline inline __attribute__((always_inline))
+#endif
+
 static __always_inline
 void __read_once_size(const volatile void *p, void *res, int size)
 {
-- 
2.39.2