On Wed, 2004-07-28 at 16:49, Andrew Morton wrote:
> Nope.   Could you take a look at the code in the top-level
> Makefile which is doing this, work out why it broke?

It seems to come down to this warning:

arch/i386/kernel/irq.c
{standard input}: Assembler messages:
{standard input}:3565: Warning: setting incorrect section type for
.bss.page_aligned

Which comes from this code in the 4k stacks code:

static char softirq_stack[NR_CPUS * THREAD_SIZE]  __attribute__((__aligned__(THREAD_SIZE), __section__(".bss.page_aligned")));
static char hardirq_stack[NR_CPUS * THREAD_SIZE]  __attribute__((__aligned__(THREAD_SIZE), __section__(".bss.page_aligned")));

Removing the __section__() fixes it, as does moving to gcc 3.2 or 3.3,
but gcc 2.95 and 3.0 still exhibit the problem.  It seems the 4k stack
developers like newer compilers than I do :) 

The gcc 2.95 section declaration looks like this:
	.section        .bss.page_aligned,"aw",@progbits
while the 3.1 section looks like this:
	.section        .bss.page_aligned,"aw",@nobits

It's definitely a bug that's been fixed:
http://sources.redhat.com/ml/binutils/2002-10/msg00507.html

I've been told that I can fix it with a carefully crafted assembly file
and maybe a change to the linker script, but all that it buys us is a
little space in the uncompressed kernel image.  Plus, the warning will
still be there at compile-time.  

I say, put them back in plain old BSS.  Patch attached.

-- Dave