Messages in this thread Patch in this message |  | | Subject | Re: 2.6.8-rc2-mm1 link errors | | From | Dave Hansen <> | | Date | Wed, 28 Jul 2004 19:06:13 -0700 |
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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 diff -rup linux-2.6.8-rc2-mm1/arch/i386/kernel/irq.c linux-2.6.8-rc2-mm1-irqstackbss/arch/i386/kernel/irq.c --- linux-2.6.8-rc2-mm1/arch/i386/kernel/irq.c 2004-07-28 18:10:40.000000000 -0700 +++ linux-2.6.8-rc2-mm1-irqstackbss/arch/i386/kernel/irq.c 2004-07-28 18:52:41.000000000 -0700 @@ -1118,8 +1118,12 @@ void init_irq_proc (void) #ifdef CONFIG_4KSTACKS -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"))); +/* + * These should really be __section__(".bss.page_aligned") as well, but + * gcc's 3.0 and earlier don't handle that correctly. + */ +static char softirq_stack[NR_CPUS * THREAD_SIZE] __attribute__((__aligned__(THREAD_SIZE))); +static char hardirq_stack[NR_CPUS * THREAD_SIZE] __attribute__((__aligned__(THREAD_SIZE))); /* * allocate per-cpu stacks for hardirq and for softirq processing |  |