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
Convert the conditional infix to a postfix to make sure this inline
assembly is unified syntax. Since gcc assumes non-unified syntax
when emitting ARM instructions, make sure to define the syntax as
unified.
This allows to use LLVM's integrated assembler.
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]>
---
I missed this instance in my previous commits and realized only
after running some randconfig.
arch/arm/include/asm/uaccess.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h
index 89a28680934b..18303bcc9990 100644
--- a/arch/arm/include/asm/uaccess.h
+++ b/arch/arm/include/asm/uaccess.h
@@ -113,10 +113,11 @@ static inline void __user *__uaccess_mask_range_ptr(const void __user *ptr,
unsigned long tmp;
asm volatile(
+ " .syntax unified\n"
" sub %1, %3, #1\n"
" subs %1, %1, %0\n"
" addhs %1, %1, #1\n"
- " subhss %1, %1, %2\n"
+ " subshs %1, %1, %2\n"
" movlo %0, #0\n"
: "+r" (safe_ptr), "=&r" (tmp)
: "r" (size), "r" (current_thread_info()->addr_limit)
--
2.20.1