From 849369d6c66d3054688672f97d31fceb8e8230fb Mon Sep 17 00:00:00 2001
From: root <root@artemis.panaceas.org>
Date: Fri, 25 Dec 2015 04:40:36 +0000
Subject: initial_commit

---
 arch/alpha/mm/extable.c | 92 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)
 create mode 100644 arch/alpha/mm/extable.c

(limited to 'arch/alpha/mm/extable.c')

diff --git a/arch/alpha/mm/extable.c b/arch/alpha/mm/extable.c
new file mode 100644
index 00000000..813c9b63
--- /dev/null
+++ b/arch/alpha/mm/extable.c
@@ -0,0 +1,92 @@
+/*
+ * linux/arch/alpha/mm/extable.c
+ */
+
+#include <linux/module.h>
+#include <linux/sort.h>
+#include <asm/uaccess.h>
+
+static inline unsigned long ex_to_addr(const struct exception_table_entry *x)
+{
+	return (unsigned long)&x->insn + x->insn;
+}
+
+static void swap_ex(void *a, void *b, int size)
+{
+	struct exception_table_entry *ex_a = a, *ex_b = b;
+	unsigned long addr_a = ex_to_addr(ex_a), addr_b = ex_to_addr(ex_b);
+	unsigned int t = ex_a->fixup.unit;
+
+	ex_a->fixup.unit = ex_b->fixup.unit;
+	ex_b->fixup.unit = t;
+	ex_a->insn = (int)(addr_b - (unsigned long)&ex_a->insn);
+	ex_b->insn = (int)(addr_a - (unsigned long)&ex_b->insn);
+}
+
+/*
+ * The exception table needs to be sorted so that the binary
+ * search that we use to find entries in it works properly.
+ * This is used both for the kernel exception table and for
+ * the exception tables of modules that get loaded.
+ */
+static int cmp_ex(const void *a, const void *b)
+{
+	const struct exception_table_entry *x = a, *y = b;
+
+	/* avoid overflow */
+	if (ex_to_addr(x) > ex_to_addr(y))
+		return 1;
+	if (ex_to_addr(x) < ex_to_addr(y))
+		return -1;
+	return 0;
+}
+
+void sort_extable(struct exception_table_entry *start,
+		  struct exception_table_entry *finish)
+{
+	sort(start, finish - start, sizeof(struct exception_table_entry),
+	     cmp_ex, swap_ex);
+}
+
+#ifdef CONFIG_MODULES
+/*
+ * Any entry referring to the module init will be at the beginning or
+ * the end.
+ */
+void trim_init_extable(struct module *m)
+{
+	/*trim the beginning*/
+	while (m->num_exentries &&
+	       within_module_init(ex_to_addr(&m->extable[0]), m)) {
+		m->extable++;
+		m->num_exentries--;
+	}
+	/*trim the end*/
+	while (m->num_exentries &&
+	       within_module_init(ex_to_addr(&m->extable[m->num_exentries-1]),
+				  m))
+		m->num_exentries--;
+}
+#endif /* CONFIG_MODULES */
+
+const struct exception_table_entry *
+search_extable(const struct exception_table_entry *first,
+	       const struct exception_table_entry *last,
+	       unsigned long value)
+{
+        while (first <= last) {
+		const struct exception_table_entry *mid;
+		unsigned long mid_value;
+
+		mid = (last - first) / 2 + first;
+		mid_value = ex_to_addr(mid);
+                if (mid_value == value)
+                        return mid;
+                else if (mid_value < value)
+                        first = mid+1;
+                else
+                        last = mid-1;
+        }
+
+        return NULL;
+}
-- 
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