[Xen-devel] [PATCH 1/2] x86/clang: fix build with indirect thunks

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

The build with clang is currently broken because clang requires asm
macros to be declared inside the same inline asm declaration where
they are used.

In order to fix this always include indirect_thunk_asm.h in the same
asm declaration where it's being used.

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: George Dunlap <George.Dunlap@xxxxxxxxxxxxx>
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Tim Deegan <tim@xxxxxxx>
Cc: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 xen/Rules.mk                           | 6 ++++--
 xen/arch/x86/extable.c                 | 3 ++-
 xen/arch/x86/x86_emulate/x86_emulate.c | 3 ++-
 xen/common/wait.c                      | 1 +
 xen/include/asm-x86/asm_defns.h        | 7 ++++---
 5 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/xen/Rules.mk b/xen/Rules.mk
index 3cf40754a6..1bd3fa1773 100644
--- a/xen/Rules.mk
+++ b/xen/Rules.mk
@@ -66,8 +66,10 @@ endif
 
 AFLAGS-y                += -D__ASSEMBLY__
 
-# Clang's built-in assembler can't handle embedded .include's
-CFLAGS-$(clang)         += -no-integrated-as
+# Clang's built-in assembler doesn't understand assembler directives without
+# an absolute value:
+# https://bugs.llvm.org/show_bug.cgi?id=27369
+AFLAGS-$(clang)         += -no-integrated-as
 
 ALL_OBJS := $(ALL_OBJS-y)
 
diff --git a/xen/arch/x86/extable.c b/xen/arch/x86/extable.c
index 72f30d9060..30893c3770 100644
--- a/xen/arch/x86/extable.c
+++ b/xen/arch/x86/extable.c
@@ -158,7 +158,8 @@ static int __init stub_selftest(void)
         memcpy(ptr, tests[i].opc, ARRAY_SIZE(tests[i].opc));
         unmap_domain_page(ptr);
 
-        asm volatile ( "INDIRECT_CALL %[stb]\n"
+        asm volatile ( INCLUDE_INDIRECT_THUNK
+                       "INDIRECT_CALL %[stb]\n"
                        ".Lret%=:\n\t"
                        ".pushsection .fixup,\"ax\"\n"
                        ".Lfix%=:\n\t"
diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c 
b/xen/arch/x86/x86_emulate/x86_emulate.c
index ff0a003902..e525e6bb0d 100644
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -867,7 +867,8 @@ static inline int mkec(uint8_t e, int32_t ec, ...)
 #ifdef __XEN__
 # define invoke_stub(pre, post, constraints...) do {                    \
     union stub_exception_token res_ = { .raw = ~0 };                    \
-    asm volatile ( pre "\n\tINDIRECT_CALL %[stub]\n\t" post "\n"        \
+    asm volatile ( INCLUDE_INDIRECT_THUNK                               \
+                   pre "\n\tINDIRECT_CALL %[stub]\n\t" post "\n"        \
                    ".Lret%=:\n\t"                                       \
                    ".pushsection .fixup,\"ax\"\n"                       \
                    ".Lfix%=:\n\t"                                       \
diff --git a/xen/common/wait.c b/xen/common/wait.c
index a57bc10d61..91dcd46342 100644
--- a/xen/common/wait.c
+++ b/xen/common/wait.c
@@ -207,6 +207,7 @@ void check_wakeup_from_wait(void)
      * restored from the stack, so are available for use here.
      */
     asm volatile (
+        INCLUDE_INDIRECT_THUNK
         "mov %1,%%"__OP"sp; INDIRECT_JMP %[ip]"
         : : "S" (wqv->stack), "D" (wqv->esp),
           "c" ((char *)get_cpu_info() - (char *)wqv->esp),
diff --git a/xen/include/asm-x86/asm_defns.h b/xen/include/asm-x86/asm_defns.h
index d2d91ca1fa..627a544326 100644
--- a/xen/include/asm-x86/asm_defns.h
+++ b/xen/include/asm-x86/asm_defns.h
@@ -16,9 +16,10 @@
 #ifdef __ASSEMBLY__
 # include <asm/indirect_thunk_asm.h>
 #else
-asm ( "\t.equ CONFIG_INDIRECT_THUNK, "
-      __stringify(IS_ENABLED(CONFIG_INDIRECT_THUNK)) );
-asm ( "\t.include \"asm/indirect_thunk_asm.h\"" );
+#define INCLUDE_INDIRECT_THUNK                                  \
+    "\t.equ CONFIG_INDIRECT_THUNK, "                            \
+    __stringify(IS_ENABLED(CONFIG_INDIRECT_THUNK)) "\n"         \
+    "\t.include \"asm/indirect_thunk_asm.h\"\n"
 #endif
 
 #ifndef __ASSEMBLY__
-- 
2.15.1


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel