[PATCH 2/4] ARM: extract out insn generation code from ftrace

[Rabin Vincent]

On Tue, Nov 22, 2011 at 17:32, Dave Martin <dave.martin at linaro.org> wrote:
> On Mon, Nov 21, 2011 at 08:43:47PM +0530, Rabin Vincent wrote:
>>  static int ftrace_modify_code(unsigned long pc, unsigned long old,
>> @@ -256,7 +203,7 @@ static int __ftrace_modify_caller(unsigned long *callsite,
>>  {
>>       unsigned long caller_fn = (unsigned long) func;
>>       unsigned long pc = (unsigned long) callsite;
>> -     unsigned long branch = ftrace_gen_branch(pc, caller_fn, false);
>> +     unsigned long branch = arm_gen_branch(pc, caller_fn);
>>       unsigned long nop = 0xe1a00000; /* mov r0, r0 */
>
> Does this code get used in Thumb-2 kernels?  So far as I can tell, this
> code is used... but it looks like it shouldn't work, due to the ARM
> specifics.

It's not used on Thumb-2.  This is only used by the function graph
tracer and that depends on !THUMB2_KERNEL.