From: Dave Hansen <haveblue@us.ibm.com>
Investigation of why the build is failing due to bogus detection of
undefined symbols: We're getting 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.
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/arch/i386/kernel/irq.c | 8 ++++++--
1 files changed, 6 insertions(+), 2 deletions(-)
diff -puN arch/i386/kernel/irq.c~268-rc2-mm1-link-errors arch/i386/kernel/irq.c
--- 25/arch/i386/kernel/irq.c~268-rc2-mm1-link-errors 2004-07-28 22:11:29.652159016 -0700
+++ 25-akpm/arch/i386/kernel/irq.c 2004-07-28 22:11:29.658158104 -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
_