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Diffstat (limited to 'arch/arm/kernel/unwind.c')
-rw-r--r--arch/arm/kernel/unwind.c129
1 files changed, 84 insertions, 45 deletions
diff --git a/arch/arm/kernel/unwind.c b/arch/arm/kernel/unwind.c
index e7e8365795c..00df012c467 100644
--- a/arch/arm/kernel/unwind.c
+++ b/arch/arm/kernel/unwind.c
@@ -67,7 +67,7 @@ EXPORT_SYMBOL(__aeabi_unwind_cpp_pr2);
struct unwind_ctrl_block {
unsigned long vrs[16]; /* virtual register set */
- unsigned long *insn; /* pointer to the current instructions word */
+ const unsigned long *insn; /* pointer to the current instructions word */
int entries; /* number of entries left to interpret */
int byte; /* current byte number in the instructions word */
};
@@ -83,8 +83,9 @@ enum regs {
PC = 15
};
-extern struct unwind_idx __start_unwind_idx[];
-extern struct unwind_idx __stop_unwind_idx[];
+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 LIST_HEAD(unwind_tables);
@@ -98,45 +99,99 @@ static LIST_HEAD(unwind_tables);
})
/*
- * Binary search in the unwind index. The entries entries are
+ * Binary search in the unwind index. The entries are
* guaranteed to be sorted in ascending order by the linker.
+ *
+ * start = first entry
+ * origin = first entry with positive offset (or stop if there is no such entry)
+ * stop - 1 = last entry
*/
-static struct unwind_idx *search_index(unsigned long addr,
- struct unwind_idx *first,
- struct unwind_idx *last)
+static const struct unwind_idx *search_index(unsigned long addr,
+ const struct unwind_idx *start,
+ const struct unwind_idx *origin,
+ const struct unwind_idx *stop)
{
- pr_debug("%s(%08lx, %p, %p)\n", __func__, addr, first, last);
+ unsigned long addr_prel31;
+
+ pr_debug("%s(%08lx, %p, %p, %p)\n",
+ __func__, addr, start, origin, stop);
+
+ /*
+ * only search in the section with the matching sign. This way the
+ * prel31 numbers can be compared as unsigned longs.
+ */
+ if (addr < (unsigned long)start)
+ /* negative offsets: [start; origin) */
+ stop = origin;
+ else
+ /* positive offsets: [origin; stop) */
+ start = origin;
+
+ /* prel31 for address relavive to start */
+ addr_prel31 = (addr - (unsigned long)start) & 0x7fffffff;
- if (addr < first->addr) {
+ while (start < stop - 1) {
+ const struct unwind_idx *mid = start + ((stop - start) >> 1);
+
+ /*
+ * As addr_prel31 is relative to start an offset is needed to
+ * make it relative to mid.
+ */
+ if (addr_prel31 - ((unsigned long)mid - (unsigned long)start) <
+ mid->addr_offset)
+ stop = mid;
+ else {
+ /* keep addr_prel31 relative to start */
+ addr_prel31 -= ((unsigned long)mid -
+ (unsigned long)start);
+ start = mid;
+ }
+ }
+
+ if (likely(start->addr_offset <= addr_prel31))
+ return start;
+ else {
pr_warning("unwind: Unknown symbol address %08lx\n", addr);
return NULL;
- } else if (addr >= last->addr)
- return last;
+ }
+}
- while (first < last - 1) {
- struct unwind_idx *mid = first + ((last - first + 1) >> 1);
+static const struct unwind_idx *unwind_find_origin(
+ const struct unwind_idx *start, const struct unwind_idx *stop)
+{
+ pr_debug("%s(%p, %p)\n", __func__, start, stop);
+ while (start < stop) {
+ const struct unwind_idx *mid = start + ((stop - start) >> 1);
- if (addr < mid->addr)
- last = mid;
+ if (mid->addr_offset >= 0x40000000)
+ /* negative offset */
+ start = mid + 1;
else
- first = mid;
+ /* positive offset */
+ stop = mid;
}
-
- return first;
+ pr_debug("%s -> %p\n", __func__, stop);
+ return stop;
}
-static struct unwind_idx *unwind_find_idx(unsigned long addr)
+static const struct unwind_idx *unwind_find_idx(unsigned long addr)
{
- struct unwind_idx *idx = NULL;
+ const struct unwind_idx *idx = NULL;
unsigned long flags;
pr_debug("%s(%08lx)\n", __func__, addr);
- if (core_kernel_text(addr))
+ if (core_kernel_text(addr)) {
+ if (unlikely(!__origin_unwind_idx))
+ __origin_unwind_idx =
+ unwind_find_origin(__start_unwind_idx,
+ __stop_unwind_idx);
+
/* main unwind table */
idx = search_index(addr, __start_unwind_idx,
- __stop_unwind_idx - 1);
- else {
+ __origin_unwind_idx,
+ __stop_unwind_idx);
+ } else {
/* module unwind tables */
struct unwind_table *table;
@@ -145,7 +200,8 @@ static struct unwind_idx *unwind_find_idx(unsigned long addr)
if (addr >= table->begin_addr &&
addr < table->end_addr) {
idx = search_index(addr, table->start,
- table->stop - 1);
+ table->origin,
+ table->stop);
/* Move-to-front to exploit common traces */
list_move(&table->list, &unwind_tables);
break;
@@ -274,7 +330,7 @@ static int unwind_exec_insn(struct unwind_ctrl_block *ctrl)
int unwind_frame(struct stackframe *frame)
{
unsigned long high, low;
- struct unwind_idx *idx;
+ const struct unwind_idx *idx;
struct unwind_ctrl_block ctrl;
/* only go to a higher address on the stack */
@@ -399,7 +455,6 @@ struct unwind_table *unwind_table_add(unsigned long start, unsigned long size,
unsigned long text_size)
{
unsigned long flags;
- struct unwind_idx *idx;
struct unwind_table *tab = kmalloc(sizeof(*tab), GFP_KERNEL);
pr_debug("%s(%08lx, %08lx, %08lx, %08lx)\n", __func__, start, size,
@@ -408,15 +463,12 @@ struct unwind_table *unwind_table_add(unsigned long start, unsigned long size,
if (!tab)
return tab;
- tab->start = (struct unwind_idx *)start;
- tab->stop = (struct unwind_idx *)(start + size);
+ tab->start = (const struct unwind_idx *)start;
+ tab->stop = (const struct unwind_idx *)(start + size);
+ tab->origin = unwind_find_origin(tab->start, tab->stop);
tab->begin_addr = text_addr;
tab->end_addr = text_addr + text_size;
- /* Convert the symbol addresses to absolute values */
- for (idx = tab->start; idx < tab->stop; idx++)
- idx->addr = prel31_to_addr(&idx->addr);
-
spin_lock_irqsave(&unwind_lock, flags);
list_add_tail(&tab->list, &unwind_tables);
spin_unlock_irqrestore(&unwind_lock, flags);
@@ -437,16 +489,3 @@ void unwind_table_del(struct unwind_table *tab)
kfree(tab);
}
-
-int __init unwind_init(void)
-{
- struct unwind_idx *idx;
-
- /* Convert the symbol addresses to absolute values */
- for (idx = __start_unwind_idx; idx < __stop_unwind_idx; idx++)
- idx->addr = prel31_to_addr(&idx->addr);
-
- pr_debug("unwind: ARM stack unwinding initialised\n");
-
- return 0;
-}