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sh: Replace DEBUG_STACKOVERFLOW with STACK_DEBUG.

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STACK_DEBUG ties in to mcount in order to do function-granular stack
overflow checks as opposed to lazily checking from IRQ context. As the
default is nohz, the frequency of overflow checking is too irregular to
catch much useful information, and so the mcount approach employed by
sparc64 is adopted instead.

This kills off the old check entirely from the do_IRQ() path and now
adopts CONFIG_MCOUNT instead.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Paul Mundt 2009-07-11 20:05:34 +09:00
parent 473d1cf4ee
commit 9f14b84afd
2 changed files with 4 additions and 30 deletions
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17
arch/sh/Kconfig.debug
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@ -61,12 +61,14 @@ config EARLY_PRINTK
select both the EARLY_SCIF_CONSOLE and SH_STANDARD_BIOS, using
the kernel command line option to toggle back and forth.
config DEBUG_STACKOVERFLOW
config STACK_DEBUG
bool "Check for stack overflows"
depends on DEBUG_KERNEL && SUPERH32
help
This option will cause messages to be printed if free stack space
drops below a certain limit.
drops below a certain limit. Saying Y here will add overhead to
every function call and will therefore incur a major
performance hit. Most users should say N.
config DEBUG_STACK_USAGE
bool "Stack utilization instrumentation"
@ -123,17 +125,6 @@ config SH64_SR_WATCH
bool "Debug: set SR.WATCH to enable hardware watchpoints and trace"
depends on SUPERH64
config STACK_DEBUG
bool "Enable diagnostic checks of the kernel stack"
depends on FUNCTION_TRACER
select DEBUG_STACKOVERFLOW
default n
help
This option allows checks to be performed on the kernel stack
at runtime. Saying Y here will add overhead to every function
call and will therefore incur a major performance hit. Most
users should say N.
config MCOUNT
def_bool y
depends on SUPERH32

17
arch/sh/kernel/irq.c
View File

@ -114,23 +114,6 @@ asmlinkage int do_IRQ(unsigned int irq, struct pt_regs *regs)
#endif
irq_enter();
#ifdef CONFIG_DEBUG_STACKOVERFLOW
/* Debugging check for stack overflow: is there less than 1KB free? */
{
long sp;
__asm__ __volatile__ ("and r15, %0" :
"=r" (sp) : "0" (THREAD_SIZE - 1));
if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
printk("do_IRQ: stack overflow: %ld\n",
sp - sizeof(struct thread_info));
dump_stack();
}
}
#endif
irq = irq_demux(intc_evt2irq(irq));
#ifdef CONFIG_IRQSTACKS