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sh: Decouple 4k and soft/hardirq stacks. 

While using separate IRQ stacks can cut down on stack consumption,
many users can also use 4k stacks directly without the additional
need of separate stacks for soft and hardirqs.

With this split, we support the same rationale for 4KSTACKS as
m68knommu, with the IRQSTACKS abstraction as per ppc64.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Paul Mundt 2007-11-02 12:16:51 +09:00
parent 0e670685e4
commit 110ed28246
3 changed files with 13 additions and 5 deletions
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8
arch/sh/Kconfig.debug
View File

@ -86,6 +86,14 @@ config 4KSTACKS
on the VM subsystem for higher order allocations. This option
will also use IRQ stacks to compensate for the reduced stackspace.
config IRQSTACKS
bool "Use separate kernel stacks when processing interrupts"
depends on DEBUG_KERNEL
help
If you say Y here the kernel will use separate kernel stacks
for handling hard and soft interrupts. This can help avoid
overflowing the process kernel stacks.
config SH_KGDB
bool "Include KGDB kernel debugger"
select FRAME_POINTER

8
arch/sh/kernel/irq.c
View File

@ -69,7 +69,7 @@ int show_interrupts(struct seq_file *p, void *v)
}
#endif
#ifdef CONFIG_4KSTACKS
#ifdef CONFIG_IRQSTACKS
/*
* per-CPU IRQ handling contexts (thread information and stack)
*/
@ -85,7 +85,7 @@ static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
asmlinkage int do_IRQ(unsigned int irq, struct pt_regs *regs)
{
struct pt_regs *old_regs = set_irq_regs(regs);
#ifdef CONFIG_4KSTACKS
#ifdef CONFIG_IRQSTACKS
union irq_ctx *curctx, *irqctx;
#endif
@ -109,7 +109,7 @@ asmlinkage int do_IRQ(unsigned int irq, struct pt_regs *regs)
irq = irq_demux(evt2irq(irq));
#ifdef CONFIG_4KSTACKS
#ifdef CONFIG_IRQSTACKS
curctx = (union irq_ctx *)current_thread_info();
irqctx = hardirq_ctx[smp_processor_id()];
@ -157,7 +157,7 @@ asmlinkage int do_IRQ(unsigned int irq, struct pt_regs *regs)
return 1;
}
#ifdef CONFIG_4KSTACKS
#ifdef CONFIG_IRQSTACKS
static char softirq_stack[NR_CPUS * THREAD_SIZE]
__attribute__((__section__(".bss.page_aligned")));

2
include/asm-sh/irq.h
View File

@ -41,7 +41,7 @@ static inline int generic_irq_demux(int irq)
#define irq_canonicalize(irq) (irq)
#define irq_demux(irq) sh_mv.mv_irq_demux(irq)
#ifdef CONFIG_4KSTACKS
#ifdef CONFIG_IRQSTACKS
extern void irq_ctx_init(int cpu);
extern void irq_ctx_exit(int cpu);
# define __ARCH_HAS_DO_SOFTIRQ