This series of patches aims to simplify the mcount address adjustment for ftrace. The frace code wants to know the start address of each function, not the address of the relocation against the mcount symbol which have been recorded to the __mcount_loc section. The ftrace_call_adjust function is used to calculate the start address of the function from the mcount relocation at runtime. For x86, ia64 and s390 the adjustment is a constant offset. There is no need to do the adjustment at runtime, it can be done by recordmcount at compile time. Blackfin already does this with the mcount_adjust variable in the pearl version of recordmcount. After teaching the C version of recordmcount about mcount_adjust x86, ia64 and s390 can be converted to a nop ftrace_call_adjust function. That leaves arm as the last remaining architecture with a non trivial ftrace_call_adjust function. There the least significant bit is removed from the address with an and operation. The comment says this is done for Thumb-2. This implies that for Thumb-1 the offset is 0 and for Thumb-2 the offset is -1, correct? If there is a way to distinguish the two targets in recordmcount at compile time we could convert arm as well. Which would allow us to remove the ftrace_call_adjust function. -- blue skies, Martin. "Reality continues to ruin my life." - Calvin. -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
