Re: [PATCH] powerpc: fix xmon disassembler for little-endian

Tom Musta wrote:

On 12/2/2013 3:10 AM, Philippe Bergheaud wrote:

quoted

This patch fixes the disassembler of the powerpc kernel debugger xmon,
for little-endian.

Signed-off-by: Philippe Bergheaud <redacted>
---
arch/powerpc/xmon/xmon.c |    4 ++++
1 file changed, 4 insertions(+)

diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index af9d346..6c27804 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c

@@ -171,7 +171,11 @@ extern void xmon_leave(void);

#define REG		"%.8lx"
#endif

+#ifdef __LITTLE_ENDIAN__
+#define GETWORD(v)	(((v)[3] << 24) + ((v)[2] << 16) + ((v)[1] << 8) + (v)[0])
+#else
#define GETWORD(v)	(((v)[0] << 24) + ((v)[1] << 16) + ((v)[2] << 8) + (v)[3])
+#endif

#define isxdigit(c)	(('0' <= (c) && (c) <= '9') \
			 || ('a' <= (c) && (c) <= 'f') \

Philippe:  Wouldn't it be better to just do a 32-bit load and let the endianness be worked out
by the hardware?  i.e.

#define GETWORD(v) (*(u32 *)v)

Yes, your alternative is better.
Wouldn't it narrow the scope of the macro to aligned words on POWER7?
I think that all references to GETWORD operate on aligned words anyway.

Philippe