linux-kernel - [PATCH] ARM: alignment: Use is_wide_instruction() to check wide instruction

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Date:	Fri, 10 Apr 2015 22:05:41 +0800
From:	Yingjoe Chen <yingjoe.chen@...iatek.com>
To:	Russell King <linux@....linux.org.uk>
CC:	Catalin Marinas <catalin.marinas@....com>,
	<linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>, <srv_heupstream@...iatek.com>,
	Yingjoe Chen <yingjoe.chen@...iatek.com>
Subject: [PATCH] ARM: alignment: Use is_wide_instruction() to check wide instruction


I first notice the comment is incorrect, then I realize there's another
macro which do exactly the same thing.
Tested with hand written userspace program with a few wide instructions
to make sure this still work as expect.

8<-------------------------------------------------
do_alignment() is using locally added IS_T32() macro to check if an
instruction is a Thumb-2 32 bit instruction. The macro
is_wide_instruction() is doing the same thing, with slightly faster
implementation.
Change to use is_wide_instruction() in do_alignment() and remove
IS_T32().

Signed-off-by: Yingjoe Chen <yingjoe.chen@...iatek.com>
---
 arch/arm/mm/alignment.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/arm/mm/alignment.c b/arch/arm/mm/alignment.c
index 2c0c541..f8e82f5 100644
--- a/arch/arm/mm/alignment.c
+++ b/arch/arm/mm/alignment.c
@@ -71,10 +71,6 @@
 
 #define BAD_INSTR 	0xdeadc0de
 
-/* Thumb-2 32 bit format per ARMv7 DDI0406A A6.3, either f800h,e800h,f800h */
-#define IS_T32(hi16) \
-	(((hi16) & 0xe000) == 0xe000 && ((hi16) & 0x1800))
-
 static unsigned long ai_user;
 static unsigned long ai_sys;
 static void *ai_sys_last_pc;
@@ -770,7 +766,7 @@ do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 		tinstr = __mem_to_opcode_thumb16(tinstr);
 		if (!fault) {
 			if (cpu_architecture() >= CPU_ARCH_ARMv7 &&
-			    IS_T32(tinstr)) {
+			    is_wide_instruction(tinstr)) {
 				/* Thumb-2 32-bit */
 				u16 tinst2 = 0;
 				fault = probe_kernel_address(ptr + 1, tinst2);
-- 
1.8.1.1.dirty

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