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 <[email protected]>
---
arch/arm/include/asm/domain.h | 6 ++++--
arch/arm/include/asm/futex.h | 3 ++-
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)
--
2.20.1
