[Xen-devel] [PATCH 3/8] xen/x86: Remove %z modifier from inline assembly

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

Clang doesn't support the %z modifier.  Replace both uses with an explicit l
suffix, and cover the changes with BUILD_BUG_ON()s

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
---
 xen/arch/x86/xstate.c          | 3 ++-
 xen/include/asm-x86/spinlock.h | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/xstate.c b/xen/arch/x86/xstate.c
index c5d17ff..4f2fb8e 100644
--- a/xen/arch/x86/xstate.c
+++ b/xen/arch/x86/xstate.c
@@ -353,11 +353,12 @@ void xrstor(struct vcpu *v, uint64_t mask)
     {
         switch ( __builtin_expect(ptr->fpu_sse.x[FPU_WORD_SIZE_OFFSET], 8) )
         {
+            BUILD_BUG_ON(sizeof(faults) != 4); /* Clang doesn't support %z in 
asm. */
 #define XRSTOR(pfx) \
         alternative_io("1: .byte " pfx "0x0f,0xae,0x2f\n" \
                        "3:\n" \
                        "   .section .fixup,\"ax\"\n" \
-                       "2: inc%z[faults] %[faults]\n" \
+                       "2: incl %[faults]\n" \
                        "   jmp 3b\n" \
                        "   .previous\n" \
                        _ASM_EXTABLE(1b, 2b), \
diff --git a/xen/include/asm-x86/spinlock.h b/xen/include/asm-x86/spinlock.h
index 70a85af..be72c0f 100644
--- a/xen/include/asm-x86/spinlock.h
+++ b/xen/include/asm-x86/spinlock.h
@@ -2,7 +2,8 @@
 #define __ASM_SPINLOCK_H
 
 #define _raw_read_unlock(l) \
-    asm volatile ( "lock; dec%z0 %0" : "+m" ((l)->lock) :: "memory" )
+    BUILD_BUG_ON(sizeof((l)->lock) != 4); /* Clang doesn't support %z in asm. 
*/ \
+    asm volatile ( "lock; decl %0" : "+m" ((l)->lock) :: "memory" )
 
 /*
  * On x86 the only reordering is of reads with older writes.  In the
-- 
2.1.4


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