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Commit 9f14b84a authored by Paul Mundt's avatar Paul Mundt
Browse files

sh: Replace DEBUG_STACKOVERFLOW with STACK_DEBUG. 



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: default avatarPaul Mundt <lethal@linux-sh.org>
parent 473d1cf4

arch/sh/Kconfig.debug

+4 −13
Original line number Diff line number Diff line
@@ -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

arch/sh/kernel/irq.c

+0 −17
Original line number Diff line number Diff line
@@ -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