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SubjectRe: [PATCH RT] arm/unwind: fail on unwind in irq disabled regions
* Thomas Gleixner | 2014-02-13 23:57:45 [+0100]:

>If we really end up with unwinding then the few cycles to follow the
>stack are not that important anymore. We really want that output.

Here you go.

diff --git a/arch/arm/kernel/unwind.c b/arch/arm/kernel/unwind.c
index 2af232d..bbafc67 100644
--- a/arch/arm/kernel/unwind.c
+++ b/arch/arm/kernel/unwind.c
@@ -87,7 +87,7 @@ extern const struct unwind_idx __start_unwind_idx[];
static const struct unwind_idx *__origin_unwind_idx;
extern const struct unwind_idx __stop_unwind_idx[];

-static DEFINE_SPINLOCK(unwind_lock);
+static DEFINE_RAW_SPINLOCK(unwind_lock);
static LIST_HEAD(unwind_tables);

/* Convert a prel31 symbol to an absolute address */
@@ -195,12 +195,7 @@ static const struct unwind_idx *unwind_find_idx(unsigned long addr)
/* module unwind tables */
struct unwind_table *table;

-#ifdef CONFIG_PREEMPT_RT_FULL
- if (irqs_disabled())
- goto out;
-#endif
-
- spin_lock_irqsave(&unwind_lock, flags);
+ raw_spin_lock_irqsave(&unwind_lock, flags);
list_for_each_entry(table, &unwind_tables, list) {
if (addr >= table->begin_addr &&
addr < table->end_addr) {
@@ -212,11 +207,10 @@ static const struct unwind_idx *unwind_find_idx(unsigned long addr)
break;
}
}
- spin_unlock_irqrestore(&unwind_lock, flags);
+ raw_spin_unlock_irqrestore(&unwind_lock, flags);
}

pr_debug("%s: idx = %p\n", __func__, idx);
-out:
return idx;
}

@@ -351,9 +345,7 @@ int unwind_frame(struct stackframe *frame)

idx = unwind_find_idx(frame->pc);
if (!idx) {
-#ifndef CONFIG_PREEMPT_RT_FULL
pr_warning("unwind: Index not found %08lx\n", frame->pc);
-#endif
return -URC_FAILURE;
}

@@ -477,9 +469,9 @@ struct unwind_table *unwind_table_add(unsigned long start, unsigned long size,
tab->begin_addr = text_addr;
tab->end_addr = text_addr + text_size;

- spin_lock_irqsave(&unwind_lock, flags);
+ raw_spin_lock_irqsave(&unwind_lock, flags);
list_add_tail(&tab->list, &unwind_tables);
- spin_unlock_irqrestore(&unwind_lock, flags);
+ raw_spin_unlock_irqrestore(&unwind_lock, flags);

return tab;
}
@@ -491,9 +483,9 @@ void unwind_table_del(struct unwind_table *tab)
if (!tab)
return;

- spin_lock_irqsave(&unwind_lock, flags);
+ raw_spin_lock_irqsave(&unwind_lock, flags);
list_del(&tab->list);
- spin_unlock_irqrestore(&unwind_lock, flags);
+ raw_spin_unlock_irqrestore(&unwind_lock, flags);

kfree(tab);
}
--
1.9.0.rc3
>Thanks,
>
> tglx

Sebastian


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