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-rw-r--r--arch/parisc/Kconfig8
-rw-r--r--arch/parisc/include/asm/processor.h19
-rw-r--r--arch/parisc/kernel/entry.S41
-rw-r--r--arch/parisc/kernel/irq.c28
4 files changed, 94 insertions, 2 deletions
diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index fe4afb0f152f..cad060f288cf 100644
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -243,6 +243,14 @@ config SMP
If you don't know what to do here, say N.
+config IRQSTACKS
+ bool "Use separate kernel stacks when processing interrupts"
+ default n
+ 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 HOTPLUG_CPU
bool
default y if SMP
diff --git a/arch/parisc/include/asm/processor.h b/arch/parisc/include/asm/processor.h
index 09b54a57a48d..242f06a5fbd8 100644
--- a/arch/parisc/include/asm/processor.h
+++ b/arch/parisc/include/asm/processor.h
@@ -20,8 +20,6 @@
#endif /* __ASSEMBLY__ */
-#define KERNEL_STACK_SIZE (4*PAGE_SIZE)
-
/*
* Default implementation of macro that returns current
* instruction pointer ("program counter").
@@ -61,6 +59,23 @@
#ifndef __ASSEMBLY__
/*
+ * IRQ STACK - used for irq handler
+ */
+#ifdef __KERNEL__
+
+#define IRQ_STACK_SIZE (4096 << 2) /* 16k irq stack size */
+
+union irq_stack_union {
+ unsigned long stack[IRQ_STACK_SIZE/sizeof(unsigned long)];
+};
+
+DECLARE_PER_CPU(union irq_stack_union, irq_stack_union);
+
+void call_on_stack(unsigned long p1, void *func, unsigned long new_stack);
+
+#endif /* __KERNEL__ */
+
+/*
* Data detected about CPUs at boot time which is the same for all CPU's.
* HP boxes are SMP - ie identical processors.
*
diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
index 3f3326d876f7..4bb96ad9b0b1 100644
--- a/arch/parisc/kernel/entry.S
+++ b/arch/parisc/kernel/entry.S
@@ -2010,6 +2010,47 @@ ftrace_stub:
ENDPROC(return_to_handler)
#endif /* CONFIG_FUNCTION_TRACER */
+#ifdef CONFIG_IRQSTACKS
+/* void call_on_stack(unsigned long param1, void *func,
+ unsigned long new_stack) */
+ENTRY(call_on_stack)
+ copy %sp, %r1
+
+ /* Regarding the HPPA calling conventions for function pointers,
+ we assume the PIC register is not changed across call. For
+ CONFIG_64BIT, the argument pointer is left to point at the
+ argument region allocated for the call to call_on_stack. */
+# ifdef CONFIG_64BIT
+ /* Switch to new stack. We allocate two 128 byte frames. */
+ ldo 256(%arg2), %sp
+ /* Save previous stack pointer and return pointer in frame marker */
+ STREG %rp, -144(%sp)
+ /* Calls always use function descriptor */
+ LDREG 16(%arg1), %arg1
+ bve,l (%arg1), %rp
+ STREG %r1, -136(%sp)
+ LDREG -144(%sp), %rp
+ bve (%rp)
+ LDREG -136(%sp), %sp
+# else
+ /* Switch to new stack. We allocate two 64 byte frames. */
+ ldo 128(%arg2), %sp
+ /* Save previous stack pointer and return pointer in frame marker */
+ STREG %r1, -68(%sp)
+ STREG %rp, -84(%sp)
+ /* Calls use function descriptor if PLABEL bit is set */
+ bb,>=,n %arg1, 30, 1f
+ depwi 0,31,2, %arg1
+ LDREG 0(%arg1), %arg1
+1:
+ be,l 0(%sr4,%arg1), %sr0, %r31
+ copy %r31, %rp
+ LDREG -84(%sp), %rp
+ bv (%rp)
+ LDREG -68(%sp), %sp
+# endif /* CONFIG_64BIT */
+ENDPROC(call_on_stack)
+#endif /* CONFIG_IRQSTACKS */
get_register:
/*
diff --git a/arch/parisc/kernel/irq.c b/arch/parisc/kernel/irq.c
index 61e51ac85659..810f9cf89e48 100644
--- a/arch/parisc/kernel/irq.c
+++ b/arch/parisc/kernel/irq.c
@@ -358,6 +358,29 @@ static inline void stack_overflow_check(struct pt_regs *regs)
#endif
}
+#ifdef CONFIG_IRQSTACKS
+DEFINE_PER_CPU(union irq_stack_union, irq_stack_union);
+
+static void execute_on_irq_stack(void *func, unsigned long param1)
+{
+ unsigned long *irq_stack_start;
+ unsigned long irq_stack;
+ int cpu = smp_processor_id();
+
+ irq_stack_start = &per_cpu(irq_stack_union, cpu).stack[0];
+ irq_stack = (unsigned long) irq_stack_start;
+ irq_stack = ALIGN(irq_stack, 16); /* align for stack frame usage */
+
+ BUG_ON(*irq_stack_start); /* report bug if we were called recursive. */
+ *irq_stack_start = 1;
+
+ /* This is where we switch to the IRQ stack. */
+ call_on_stack(param1, func, irq_stack);
+
+ *irq_stack_start = 0;
+}
+#endif /* CONFIG_IRQSTACKS */
+
/* ONLY called from entry.S:intr_extint() */
void do_cpu_irq_mask(struct pt_regs *regs)
{
@@ -393,7 +416,12 @@ void do_cpu_irq_mask(struct pt_regs *regs)
}
#endif
stack_overflow_check(regs);
+
+#ifdef CONFIG_IRQSTACKS
+ execute_on_irq_stack(&generic_handle_irq, irq);
+#else
generic_handle_irq(irq);
+#endif /* CONFIG_IRQSTACKS */
out:
irq_exit();