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-rw-r--r--arch/parisc/Kconfig.debug11
-rw-r--r--arch/parisc/include/asm/thread_info.h2
-rw-r--r--arch/parisc/kernel/irq.c31
-rw-r--r--arch/parisc/kernel/vmlinux.lds.S2
4 files changed, 42 insertions, 4 deletions
diff --git a/arch/parisc/Kconfig.debug b/arch/parisc/Kconfig.debug
index bc989e5..08a332f 100644
--- a/arch/parisc/Kconfig.debug
+++ b/arch/parisc/Kconfig.debug
@@ -13,3 +13,14 @@ config DEBUG_RODATA
If in doubt, say "N".
endmenu
+
+config DEBUG_STACKOVERFLOW
+ bool "Check for stack overflows"
+ default y
+ depends on DEBUG_KERNEL
+ ---help---
+ Say Y here if you want to check the overflows of kernel, IRQ
+ and exception stacks. This option will cause messages of the
+ stacks in detail when free stack space drops below a certain
+ limit.
+ If in doubt, say "N".
diff --git a/arch/parisc/include/asm/thread_info.h b/arch/parisc/include/asm/thread_info.h
index 6182832..540c88f 100644
--- a/arch/parisc/include/asm/thread_info.h
+++ b/arch/parisc/include/asm/thread_info.h
@@ -40,7 +40,7 @@ struct thread_info {
/* thread information allocation */
-#define THREAD_SIZE_ORDER 2
+#define THREAD_SIZE_ORDER 2 /* PA-RISC requires at least 16k stack */
/* Be sure to hunt all references to this down when you change the size of
* the kernel stack */
#define THREAD_SIZE (PAGE_SIZE << THREAD_SIZE_ORDER)
diff --git a/arch/parisc/kernel/irq.c b/arch/parisc/kernel/irq.c
index 8094d3e..61e51ac 100644
--- a/arch/parisc/kernel/irq.c
+++ b/arch/parisc/kernel/irq.c
@@ -330,6 +330,34 @@ static inline int eirr_to_irq(unsigned long eirr)
return (BITS_PER_LONG - bit) + TIMER_IRQ;
}
+int sysctl_panic_on_stackoverflow = 1;
+
+static inline void stack_overflow_check(struct pt_regs *regs)
+{
+#ifdef CONFIG_DEBUG_STACKOVERFLOW
+ #define STACK_MARGIN (256*6)
+
+ /* Our stack starts directly behind the thread_info struct. */
+ unsigned long stack_start = (unsigned long) current_thread_info();
+ unsigned long sp = regs->gr[30];
+
+ /* if sr7 != 0, we interrupted a userspace process which we do not want
+ * to check for stack overflow. We will only check the kernel stack. */
+ if (regs->sr[7])
+ return;
+
+ if (likely((sp - stack_start) < (THREAD_SIZE - STACK_MARGIN)))
+ return;
+
+ pr_emerg("stackcheck: %s will most likely overflow kernel stack "
+ "(sp:%lx, stk bottom-top:%lx-%lx)\n",
+ current->comm, sp, stack_start, stack_start + THREAD_SIZE);
+
+ if (sysctl_panic_on_stackoverflow)
+ panic("low stack detected by irq handler - check messages\n");
+#endif
+}
+
/* ONLY called from entry.S:intr_extint() */
void do_cpu_irq_mask(struct pt_regs *regs)
{
@@ -364,6 +392,7 @@ void do_cpu_irq_mask(struct pt_regs *regs)
goto set_out;
}
#endif
+ stack_overflow_check(regs);
generic_handle_irq(irq);
out:
@@ -420,6 +449,4 @@ void __init init_IRQ(void)
cpu_eiem = EIEM_MASK(TIMER_IRQ);
#endif
set_eiem(cpu_eiem); /* EIEM : enable all external intr */
-
}
-
diff --git a/arch/parisc/kernel/vmlinux.lds.S b/arch/parisc/kernel/vmlinux.lds.S
index 64a9998..4bb095a 100644
--- a/arch/parisc/kernel/vmlinux.lds.S
+++ b/arch/parisc/kernel/vmlinux.lds.S
@@ -95,7 +95,7 @@ SECTIONS
NOTES
/* Data */
- RW_DATA_SECTION(L1_CACHE_BYTES, PAGE_SIZE, THREAD_SIZE)
+ RW_DATA_SECTION(L1_CACHE_BYTES, PAGE_SIZE, PAGE_SIZE)
/* PA-RISC locks requires 16-byte alignment */
. = ALIGN(16);
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