1 files changed, 107 insertions, 0 deletions
diff --git a/arch/sparc/mm/extable.c b/arch/sparc/mm/extable.c
new file mode 100644
index 000000000..241b40641
--- /dev/null
+++ b/arch/sparc/mm/extable.c
@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * linux/arch/sparc/mm/extable.c
+ */
+
+#include <linux/module.h>
+#include <linux/extable.h>
+#include <linux/uaccess.h>
+
+void sort_extable(struct exception_table_entry *start,
+		  struct exception_table_entry *finish)
+{
+}
+
+/* Caller knows they are in a range if ret->fixup == 0 */
+const struct exception_table_entry *
+search_extable(const struct exception_table_entry *base,
+	       const size_t num,
+	       unsigned long value)
+{
+	int i;
+
+	/* Single insn entries are encoded as:
+	 *	word 1:	insn address
+	 *	word 2:	fixup code address
+	 *
+	 * Range entries are encoded as:
+	 *	word 1: first insn address
+	 *	word 2: 0
+	 *	word 3: last insn address + 4 bytes
+	 *	word 4: fixup code address
+	 *
+	 * Deleted entries are encoded as:
+	 *	word 1: unused
+	 *	word 2: -1
+	 *
+	 * See asm/uaccess.h for more details.
+	 */
+
+	/* 1. Try to find an exact match. */
+	for (i = 0; i < num; i++) {
+		if (base[i].fixup == 0) {
+			/* A range entry, skip both parts. */
+			i++;
+			continue;
+		}
+
+		/* A deleted entry; see trim_init_extable */
+		if (base[i].fixup == -1)
+			continue;
+
+		if (base[i].insn == value)
+			return &base[i];
+	}
+
+	/* 2. Try to find a range match. */
+	for (i = 0; i < (num - 1); i++) {
+		if (base[i].fixup)
+			continue;
+
+		if (base[i].insn <= value && base[i + 1].insn > value)
+			return &base[i];
+
+		i++;
+	}
+
+        return NULL;
+}
+
+#ifdef CONFIG_MODULES
+/* We could memmove them around; easier to mark the trimmed ones. */
+void trim_init_extable(struct module *m)
+{
+	unsigned int i;
+	bool range;
+
+	for (i = 0; i < m->num_exentries; i += range ? 2 : 1) {
+		range = m->extable[i].fixup == 0;
+
+		if (within_module_init(m->extable[i].insn, m)) {
+			m->extable[i].fixup = -1;
+			if (range)
+				m->extable[i+1].fixup = -1;
+		}
+		if (range)
+			i++;
+	}
+}
+#endif /* CONFIG_MODULES */
+
+/* Special extable search, which handles ranges.  Returns fixup */
+unsigned long search_extables_range(unsigned long addr, unsigned long *g2)
+{
+	const struct exception_table_entry *entry;
+
+	entry = search_exception_tables(addr);
+	if (!entry)
+		return 0;
+
+	/* Inside range?  Fix g2 and return correct fixup */
+	if (!entry->fixup) {
+		*g2 = (addr - entry->insn) / 4;
+		return (entry + 1)->fixup;
+	}
+
+	return entry->fixup;
+}