tools: relocate-rela: introduce elf16_to_cpu() and elf32_to_cpu()

Add elf16_to_cpu() and elf32_to_cpu() functions that allow to read data in
both big-endian and little-endian formats.

Reviewed-by: Michal Simek <michal.simek@amd.com>
Signed-off-by: Ovidiu Panait <ovpanait@gmail.com>
Link: https://lore.kernel.org/r/20230311173838.521804-2-ovpanait@gmail.com
Signed-off-by: Michal Simek <michal.simek@amd.com>
diff --git a/tools/relocate-rela.c b/tools/relocate-rela.c
index 689e2d4..b27c41b 100644
--- a/tools/relocate-rela.c
+++ b/tools/relocate-rela.c
@@ -45,6 +45,7 @@
 #endif
 
 static int ei_class;
+static int ei_data;
 
 static uint64_t rela_start, rela_end, text_base, dyn_start;
 
@@ -61,6 +62,22 @@
 	}
 }
 
+static uint16_t elf16_to_cpu(uint16_t data)
+{
+	if (ei_data == ELFDATA2LSB)
+		return le16_to_cpu(data);
+
+	return be16_to_cpu(data);
+}
+
+static uint32_t elf32_to_cpu(uint32_t data)
+{
+	if (ei_data == ELFDATA2LSB)
+		return le32_to_cpu(data);
+
+	return be32_to_cpu(data);
+}
+
 static bool supported_rela(Elf64_Rela *rela)
 {
 	uint64_t mask = 0xffffffffULL; /* would be different on 32-bit */
@@ -384,6 +401,9 @@
 	ei_class = e_ident[4];
 	debug("EI_CLASS(1=32bit, 2=64bit) %d\n", ei_class);
 
+	ei_data = e_ident[5];
+	debug("EI_DATA(1=little endian, 2=big endian) %d\n", ei_data);
+
 	if (ei_class == 2)
 		return decode_elf64(felf, argv);