ARM: 8851/1: add TUSERCOND() macro for conditional postfix

Unified assembly syntax requires conditionals to be postfixes.
TUSER() currently only takes a single argument which then gets
appended t (with translation) on every instruction.

This fixes a build error when using LLVM's integrated assembler:
  In file included from kernel/futex.c:72:
  ./arch/arm/include/asm/futex.h:116:3: error: invalid instruction, did you mean: strt?
          "2:     " TUSER(streq) "        %3, [%4]n"
           ^
  <inline asm>:5:4: note: instantiated into assembly here
  2:      streqt  r2, [r4]
          ^~~~~~

Additionally, for GCC ".syntax unified" for inline assembly.
When compiling non-Thumb2 GCC always emits a ".syntax divided"
at the beginning of the inline assembly which makes the
assembler fail. Since GCC 5 there is the -masm-syntax-unified
GCC option which make GCC assume unified syntax asm and hence
emits ".syntax unified" even in ARM mode. However, the option
is broken since GCC version 6 (see GCC PR88648 [1]). Work
around by adding ".syntax unified" as part of the inline
assembly.

[0] https://gcc.gnu.org/onlinedocs/gcc/ARM-Options.html#index-masm-syntax-unified
[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88648

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

2 files changed, 6 insertions, 3 deletions

diff --git a/arch/arm/include/asm/domain.h b/arch/arm/include/asm/domain.h
index 99d9f630d6b6..1888c2d15da5 100644
--- a/arch/arm/include/asm/domain.h
+++ b/arch/arm/include/asm/domain.h
@@ -133,9 +133,11 @@ static inline void modify_domain(unsigned dom, unsigned type)	{ }
  * instructions (inline assembly)
  */
 #ifdef CONFIG_CPU_USE_DOMAINS
-#define TUSER(instr)    #instr "t"
+#define TUSER(instr)            TUSERCOND(instr, )
+#define TUSERCOND(instr, cond)  #instr "t" #cond
 #else
-#define TUSER(instr)    #instr
+#define TUSER(instr)            TUSERCOND(instr, )
+#define TUSERCOND(instr, cond)  #instr #cond
 #endif
 
 #else /* __ASSEMBLY__ */
diff --git a/arch/arm/include/asm/futex.h b/arch/arm/include/asm/futex.h
index 0a46676b4245..83c391b597d4 100644
--- a/arch/arm/include/asm/futex.h
+++ b/arch/arm/include/asm/futex.h
@@ -110,10 +110,11 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
         preempt_disable();
         __ua_flags = uaccess_save_and_enable();
         __asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n"
+        "       .syntax unified\n"
         "1:     " TUSER(ldr) "  %1, [%4]\n"
         "       teq     %1, %2\n"
         "       it      eq      @ explicit IT needed for the 2b label\n"
-        "2:     " TUSER(streq) "        %3, [%4]\n"
+        "2:     " TUSERCOND(str, eq) "  %3, [%4]\n"
         __futex_atomic_ex_table("%5")
         : "+r" (ret), "=&r" (val)
         : "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT)