Subject: [PATCH 08/29] ARM: 8852/1: uaccess: use unified assembler language syntax

From: Stefan Agner <[email-masked]>
Date: Sat, 23 Mar 2019 12:10:44 +0100

commit fe09d9c641f2064390afabdf436fe09b35e075ff upstream.

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-masked]>
Signed-off-by: Russell King <[email-masked]>
Signed-off-by: Nick Desaulniers <[email-masked]>
---
 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 a50f9b4e2574..14827d583e26 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)
-- 
2.31.0.rc2.261.g7f71774620-goog