[Kgdb-bugreport] [PATCH, RFC] kgdb, arm: use macro in arch_kgdb_ops

[Vincent S. <v-s...@ti...>]

Use byteorder macros to deal with endianness while declaring breakpoint
instruction in arch_kgdb_ops. Use the KGDB_BREAKINST macro instead of
hardcoding the breakpoint instruction in hexadecimal.

Signed-off-by: Vincent Stehlé <v-s...@ti...>
Cc: Jason Wessel <jas...@wi...>
Cc: kgd...@li...
---


Hi,

I would like to propose the following changes in the way the kgdb breakpoint
instructions are declared. This has the benefit to remove one hardcoded value,
and to get rid of the if/else on __ARMEB__. Also, this should ease support of
thumb2 kernel.

What is your opinion on this, please?

This has been tested good on an (ARMEB) OMAP5 platform.

Best regards,

V.


 arch/arm/kernel/kgdb.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/arch/arm/kernel/kgdb.c b/arch/arm/kernel/kgdb.c
index 778c2f7..71e2550 100644
--- a/arch/arm/kernel/kgdb.c
+++ b/arch/arm/kernel/kgdb.c
@@ -13,6 +13,7 @@
 #include <linux/kdebug.h>
 #include <linux/kgdb.h>
 #include <asm/traps.h>
+#include <asm/byteorder.h>
 
 struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
 {
@@ -246,10 +247,12 @@ void kgdb_arch_exit(void)
  * and we handle the normal undef case within the do_undefinstr
  * handler.
  */
+
+#define __bpt_byte(W, N) ((__constant_be32_to_cpu(W) >> ((N) * 8)) & 0xff)
+
+#define __bpt_instr(W)	{__bpt_byte(W, 3), __bpt_byte(W, 2), \
+			 __bpt_byte(W, 1), __bpt_byte(W, 0)}
+
 struct kgdb_arch arch_kgdb_ops = {
-#ifndef __ARMEB__
-	.gdb_bpt_instr		= {0xfe, 0xde, 0xff, 0xe7}
-#else /* ! __ARMEB__ */
-	.gdb_bpt_instr		= {0xe7, 0xff, 0xde, 0xfe}
-#endif
+	.gdb_bpt_instr		= __bpt_instr(KGDB_BREAKINST)
 };
-- 
1.8.1.2