Re: [PATCH 3/4] sparc32: return destination pointer on return from memcpy

[Konrad Eisele <konrad@xxxxxxxxxxx>]

David Miller wrote:
> From: Konrad Eisele <konrad@xxxxxxxxxxx>
> Date: Thu, 13 Oct 2011 09:00:04 +0200
> 
>> -/* In kernel these functions don't return a value.
>> - * One should use macros in asm/string.h for that purpose.
>> - * We return 0, so that bugs are more apparent.
>> - */
>> -#define SETUP_RETL
>> -#define RETL_INSN	clr	%o0
>> +#define SETUP_RETL	mov	%o0, %g6
>> +#define RETL_INSN	mov	%g6, %o0
> 
> Sigh...
> 
> The kernel uses %g6 as the global thread register, see
> include/asm/thread_info_32.h:
> 
> register struct thread_info *current_thread_info_reg asm("g6");
> 
> Your kernel would have crashed early in the boot if you actually
> tested this patch.
> 
> 

Isnt the simplest way to apply the original gdbstub.c patch instead?

-		ptr += strlen(strcpy(ptr, "thread:"));
+		strcpy(ptr, "thread:");
+		ptr += strlen(ptr);


Or even a simple

		strcpy(ptr, "thread:");
		ptr += 7;

In that case its the
"[PATCH 4/4] kernel,debug: SPARC KGDB stub strcpy fix" from [09/30/2011 03:47 PM].
instead of the memcpy patch.

It seems to me that memcpy is tightly programmed. Is saving 2 lines of gdbstub.c
diff worth a memcpy rewrite?

-- Konrad



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