[PATCH v5 08/12] x86/paravirt: simplify paravirt macros

Juergen Gross
2021-03-08T12:29:58Z

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@suse.com>
---
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