powerpc/64: Add module check for ELF ABI version

Override the generic module ELF check to provide a check for the ELF ABI
version. This becomes important if we allow big-endian ELF ABI V2 builds
but it doesn't hurt to check now.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221128041539.1742489-3-npiggin@gmail.com

arch/powerpc/kernel/module_64.c

@@ -31,6 +31,16 @@
    this, and makes other things simpler.  Anton?
    --RR.  */
 
+bool module_elf_check_arch(Elf_Ehdr *hdr)
+{
+	unsigned long abi_level = hdr->e_flags & 0x3;
+
+	if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2))
+		return abi_level == 2;
+	else
+		return abi_level < 2;
+}
+
 #ifdef CONFIG_PPC64_ELF_ABI_V2
 
 static func_desc_t func_desc(unsigned long addr)