1 files changed, 147 insertions, 1 deletions

diff --git a/common/kallsyms.c b/common/kallsyms.c
index 490adb9223..0218991c46 100644
--- a/common/kallsyms.c
+++ b/common/kallsyms.c
@@ -1,6 +1,7 @@
 #include <common.h>
 #include <init.h>
 #include <kallsyms.h>
+#include <asm-generic/sections.h>
 
 #ifndef DOXYGEN_SHOULD_SKIP_THIS
 
@@ -16,6 +17,13 @@ extern const unsigned long kallsyms_markers[] __attribute__((weak));
 
 #endif /* DOXYGEN_SHOULD_SKIP_THIS */
 
+static inline int is_kernel_text(unsigned long addr)
+{
+	if ((addr >= (unsigned long)_stext && addr <= (unsigned long)_etext))
+		return 1;
+	return 0;
+}
+
 /* expand a compressed symbol data into the resulting uncompressed string,
    given the offset to where the symbol is in the compressed stream */
 static unsigned int kallsyms_expand_symbol(unsigned int off, char *result)
@@ -55,6 +63,33 @@ static unsigned int kallsyms_expand_symbol(unsigned int off, char *result)
 	return off;
 }
 
+/*
+ * Find the offset on the compressed stream given and index in the
+ * kallsyms array.
+ */
+static unsigned int get_symbol_offset(unsigned long pos)
+{
+	const u8 *name;
+	int i;
+
+	/*
+	 * Use the closest marker we have. We have markers every 256 positions,
+	 * so that should be close enough.
+	 */
+	name = &kallsyms_names[kallsyms_markers[pos >> 8]];
+
+	/*
+	 * Sequentially scan all the symbols up to the point we're searching
+	 * for. Every symbol is stored in a [<len>][<len> bytes of data] format,
+	 * so we just need to add the len to the current pointer for every
+	 * symbol we wish to skip.
+	 */
+	for (i = 0; i < (pos & 0xFF); i++)
+		name = name + (*name) + 1;
+
+	return name - kallsyms_names;
+}
+
 /* Lookup the address for this symbol. Returns 0 if not found. */
 unsigned long kallsyms_lookup_name(const char *name)
 {
@@ -68,6 +103,117 @@ unsigned long kallsyms_lookup_name(const char *name)
 		if (strcmp(namebuf, name) == 0)
 			return kallsyms_addresses[i];
 	}
-//	return module_kallsyms_lookup_name(name);
+
+	/* module kallsyms not yet supported */
 	return 0;
 }
+
+static unsigned long get_symbol_pos(unsigned long addr,
+				    unsigned long *symbolsize,
+				    unsigned long *offset)
+{
+	unsigned long symbol_start = 0, symbol_end = 0;
+	unsigned long i, low, high, mid;
+
+	/* This kernel should never had been booted. */
+	BUG_ON(!kallsyms_addresses);
+
+	/* Do a binary search on the sorted kallsyms_addresses array. */
+	low = 0;
+	high = kallsyms_num_syms;
+
+	while (high - low > 1) {
+		mid = low + (high - low) / 2;
+		if (kallsyms_addresses[mid] <= addr)
+			low = mid;
+		else
+			high = mid;
+	}
+
+	/*
+	 * Search for the first aliased symbol. Aliased
+	 * symbols are symbols with the same address.
+	 */
+	while (low && kallsyms_addresses[low-1] == kallsyms_addresses[low])
+		--low;
+
+	symbol_start = kallsyms_addresses[low];
+
+	/* Search for next non-aliased symbol. */
+	for (i = low + 1; i < kallsyms_num_syms; i++) {
+		if (kallsyms_addresses[i] > symbol_start) {
+			symbol_end = kallsyms_addresses[i];
+			break;
+		}
+	}
+
+	/* If we found no next symbol, we use the end of the section. */
+	if (!symbol_end) {
+		symbol_end = (unsigned long)_etext;
+	}
+
+	if (symbolsize)
+		*symbolsize = symbol_end - symbol_start;
+	if (offset)
+		*offset = addr - symbol_start;
+
+	return low;
+}
+
+/*
+ * Lookup an address
+ * - modname is set to NULL if it's in the kernel.
+ * - We guarantee that the returned name is valid until we reschedule even if.
+ *   It resides in a module.
+ * - We also guarantee that modname will be valid until rescheduled.
+ */
+const char *kallsyms_lookup(unsigned long addr,
+			    unsigned long *symbolsize,
+			    unsigned long *offset,
+			    char **modname, char *namebuf)
+{
+	namebuf[KSYM_NAME_LEN - 1] = 0;
+	namebuf[0] = 0;
+
+	if (is_kernel_text(addr)) {
+		unsigned long pos;
+
+		pos = get_symbol_pos(addr, symbolsize, offset);
+		/* Grab name */
+		kallsyms_expand_symbol(get_symbol_offset(pos), namebuf);
+		if (modname)
+			*modname = NULL;
+		return namebuf;
+	}
+
+	/* moduled not yet supported in kallsyms */
+	return NULL;
+}
+
+/* Look up a kernel symbol and return it in a text buffer. */
+int sprint_symbol(char *buffer, unsigned long address)
+{
+	char *modname;
+	const char *name;
+	unsigned long offset, size;
+	int len;
+
+	name = kallsyms_lookup(address, &size, &offset, &modname, buffer);
+	if (!name)
+		return sprintf(buffer, "0x%lx", address);
+
+	if (name != buffer)
+		strcpy(buffer, name);
+	len = strlen(buffer);
+	buffer += len;
+
+	if (modname)
+		len += sprintf(buffer, "+%#lx/%#lx [%s]",
+						offset, size, modname);
+	else
+		len += sprintf(buffer, "+%#lx/%#lx", offset, size);
+
+	return len;
+}
+EXPORT_SYMBOL_GPL(sprint_symbol);
+