[PATCH v6 08/12] x86/paravirt: simplify paravirt macros

[Juergen Gross <jgross@xxxxxxxx>]

The central pvops call macros ____PVOP_CALL() and ____PVOP_VCALL() are
looking very similar now.

The main differences are using PVOP_VCALL_ARGS or PVOP_CALL_ARGS, which
are identical, and the return value handling.

So drop PVOP_VCALL_ARGS and instead of ____PVOP_VCALL() just use
(void)____PVOP_CALL(long, ...).

Note that it isn't easily possible to just redefine ____PVOP_VCALL()
to use ____PVOP_CALL() instead, as this would require further hiding of
commas in macro parameters.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
V3:
- new patch
V4:
- fix build warnings with clang (kernel test robot)
---
 arch/x86/include/asm/paravirt_types.h | 41 ++++++++-------------------
 1 file changed, 12 insertions(+), 29 deletions(-)

diff --git a/arch/x86/include/asm/paravirt_types.h 
b/arch/x86/include/asm/paravirt_types.h
index 42f9eef84131..45bd21647dd8 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -408,11 +408,9 @@ int paravirt_disable_iospace(void);
  * makes sure the incoming and outgoing types are always correct.
  */
 #ifdef CONFIG_X86_32
-#define PVOP_VCALL_ARGS                                                        
\
+#define PVOP_CALL_ARGS                                                 \
        unsigned long __eax = __eax, __edx = __edx, __ecx = __ecx;
 
-#define PVOP_CALL_ARGS                 PVOP_VCALL_ARGS
-
 #define PVOP_CALL_ARG1(x)              "a" ((unsigned long)(x))
 #define PVOP_CALL_ARG2(x)              "d" ((unsigned long)(x))
 #define PVOP_CALL_ARG3(x)              "c" ((unsigned long)(x))
@@ -428,12 +426,10 @@ int paravirt_disable_iospace(void);
 #define VEXTRA_CLOBBERS
 #else  /* CONFIG_X86_64 */
 /* [re]ax isn't an arg, but the return val */
-#define PVOP_VCALL_ARGS                                                \
+#define PVOP_CALL_ARGS                                         \
        unsigned long __edi = __edi, __esi = __esi,             \
                __edx = __edx, __ecx = __ecx, __eax = __eax;
 
-#define PVOP_CALL_ARGS         PVOP_VCALL_ARGS
-
 #define PVOP_CALL_ARG1(x)              "D" ((unsigned long)(x))
 #define PVOP_CALL_ARG2(x)              "S" ((unsigned long)(x))
 #define PVOP_CALL_ARG3(x)              "d" ((unsigned long)(x))
@@ -458,59 +454,46 @@ int paravirt_disable_iospace(void);
 #define PVOP_TEST_NULL(op)     ((void)pv_ops.op)
 #endif
 
-#define PVOP_RETMASK(rettype)                                          \
+#define PVOP_RETVAL(rettype)                                           \
        ({      unsigned long __mask = ~0UL;                            \
+               BUILD_BUG_ON(sizeof(rettype) > sizeof(unsigned long));  \
                switch (sizeof(rettype)) {                              \
                case 1: __mask =       0xffUL; break;                   \
                case 2: __mask =     0xffffUL; break;                   \
                case 4: __mask = 0xffffffffUL; break;                   \
                default: break;                                         \
                }                                                       \
-               __mask;                                                 \
+               __mask & __eax;                                         \
        })
 
 
-#define ____PVOP_CALL(rettype, op, clbr, call_clbr, extra_clbr, ...)   \
+#define ____PVOP_CALL(ret, op, clbr, call_clbr, extra_clbr, ...)       \
        ({                                                              \
                PVOP_CALL_ARGS;                                         \
                PVOP_TEST_NULL(op);                                     \
-               BUILD_BUG_ON(sizeof(rettype) > sizeof(unsigned long));  \
                asm volatile(paravirt_alt(PARAVIRT_CALL)                \
                             : call_clbr, ASM_CALL_CONSTRAINT           \
                             : paravirt_type(op),                       \
                               paravirt_clobber(clbr),                  \
                               ##__VA_ARGS__                            \
                             : "memory", "cc" extra_clbr);              \
-               (rettype)(__eax & PVOP_RETMASK(rettype));               \
+               ret;                                                    \
        })
 
 #define __PVOP_CALL(rettype, op, ...)                                  \
-       ____PVOP_CALL(rettype, op, CLBR_ANY, PVOP_CALL_CLOBBERS,        \
-                     EXTRA_CLOBBERS, ##__VA_ARGS__)
+       ____PVOP_CALL(PVOP_RETVAL(rettype), op, CLBR_ANY,               \
+                     PVOP_CALL_CLOBBERS, EXTRA_CLOBBERS, ##__VA_ARGS__)
 
 #define __PVOP_CALLEESAVE(rettype, op, ...)                            \
-       ____PVOP_CALL(rettype, op.func, CLBR_RET_REG,                   \
+       ____PVOP_CALL(PVOP_RETVAL(rettype), op.func, CLBR_RET_REG,      \
                      PVOP_CALLEE_CLOBBERS, , ##__VA_ARGS__)
 
-
-#define ____PVOP_VCALL(op, clbr, call_clbr, extra_clbr, ...)           \
-       ({                                                              \
-               PVOP_VCALL_ARGS;                                        \
-               PVOP_TEST_NULL(op);                                     \
-               asm volatile(paravirt_alt(PARAVIRT_CALL)                \
-                            : call_clbr, ASM_CALL_CONSTRAINT           \
-                            : paravirt_type(op),                       \
-                              paravirt_clobber(clbr),                  \
-                              ##__VA_ARGS__                            \
-                            : "memory", "cc" extra_clbr);              \
-       })
-
 #define __PVOP_VCALL(op, ...)                                          \
-       ____PVOP_VCALL(op, CLBR_ANY, PVOP_VCALL_CLOBBERS,               \
+       (void)____PVOP_CALL(, op, CLBR_ANY, PVOP_VCALL_CLOBBERS,        \
                       VEXTRA_CLOBBERS, ##__VA_ARGS__)
 
 #define __PVOP_VCALLEESAVE(op, ...)                                    \
-       ____PVOP_VCALL(op.func, CLBR_RET_REG,                           \
+       (void)____PVOP_CALL(, op.func, CLBR_RET_REG,                    \
                      PVOP_VCALLEE_CLOBBERS, , ##__VA_ARGS__)
 
 
-- 
2.26.2