[U-Boot] [PATCH 2/4] arm: add %function attribute to assembly functions

Aneesh V
2012-02-20T16:08:24Z

On Saturday 18 February 2012 10:18 PM, Albert ARIBAUD wrote:
> Hi Aneesh,
>

[...]

>>> I will get back with more details on the Linaro GCC 2012.01 later.
>>
>> I meant "the Linaro GCC 2012.01 tool-chain problem"
>>
>> This is a different problem. Some of the .rodata symbols are given an
>> odd address although they should be aligned to at least 2-byte boundary
>> ). In fact the data is actually put at the even address but the symbol's
>> value is +1 of the actual address. This is the ARM convention for Thumb
>> functions, but they have applied it here for data too. That's the
>> problem. I see that this doesn't happen to all the .rodata in SPL.
>> Neither could I reproduce it with a small program. But the workaround
>> for this problem is to avoid -fdata-sections. The following patch works
>> around it.
>>
>> diff --git a/config.mk b/config.mk
>> index ddaa477..723286a 100644
>> --- a/config.mk
>> +++ b/config.mk
>> @@ -190,7 +190,7 @@ CPPFLAGS := $(DBGFLAGS) $(OPTFLAGS) $(RELFLAGS) \
>>
>> # Enable garbage collection of un-used sections for SPL
>> ifeq ($(CONFIG_SPL_BUILD),y)
>> -CPPFLAGS += -ffunction-sections -fdata-sections
>> +CPPFLAGS += -ffunction-sections
>> LDFLAGS_FINAL += --gc-sections
>> endif
>>
>> Will you take a patch to make -fdata-sections optional, that is, having
>> it under something like CONFIG_SYS_SPL_NO_FDATA_SECTIONS?
>
> Hmm... considering you're seeing the issue in a fairly new toolchain
> release, I prefer notifying the toolchain makers, rather than removing
> the -fdata-sections from SPL even for specific boards. Can you go and
> see why the Linaro toolchain generated odd "thumb data" at all and get
> this fixed?

I tried investigating a bit. As I mentioned earlier it doesn't happen
with some other files that use the same compiler and linker commands.
So, I don't know what's going on. Also, I couldn't reproduce it with a
simple program unlike in the other cases. Anyway, I have notified
tool-chain folks at Linaro:

http://article.gmane.org/gmane.linux.linaro.toolchain/2096

br,
Aneesh