Re: [PATCH] Make alignment cflags configurable.
From: Jan-Simon Moeller
Date: Wed Aug 12 2015 - 18:32:11 EST
> You could mention that this is to fix the clang build. But why is it
> needed? It isn't that clang just doesn't accept the option, is it?
> Otherwise we could just use $(call cc-option, -falign-jumps=1) etc.
Yes it is to fix the build with clang.
I tried cc-option, but it does not improve the situation (more below).
This is why I chose the config option approach in the patch.
> Did you get to the bottom of the clang failure here? Just turning this
> off without a coherent explanation doesn't seem like the right thing to
I know it is not the final solution which is why I turned it into a config
option. We can still debate if default should be "y" or "n". This way we all
@Ingo: would it be fine if we wrap it into a config option defaulting to "y" ?
What I can say so far is that although clang warns about the unknown option
and ignores it, the resulting kernel still fails to boot somewhere early in
start_kernel(). I'm still investigating.
My current trace ends like this:
page_address_init ~ setup_arch ~ then arch/x86/kernel/setup.c:898
setup.c:898 is a printk actually ...
early_idt_handler_array[i] ~> early_idt_handler_common
The mail thread is here:
We still build with -no-integrated-as which means we use gas. Maybe the flag
is passed-on there and things get confused.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/