powerpc/32s: Fix is_module_segment() when MODULES_VADDR is defined

When MODULES_VADDR is defined, is_module_segment() shall check the
address against it instead of checking agains VMALLOC_START.

Fixes: 6ca05532 ("powerpc/32s: Use dedicated segment for modules with STRICT_KERNEL_RWX")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/07884ed033c31e074747b7eb8eaa329d15db07ec.1596641219.git.christophe.leroy@csgroup.eu

arch/powerpc/mm/book3s32/mmu.c

@@ -191,10 +191,17 @@ static bool is_module_segment(unsigned long addr)
 {
 	if (!IS_ENABLED(CONFIG_MODULES))
 		return false;
+#ifdef MODULES_VADDR
+	if (addr < ALIGN_DOWN(MODULES_VADDR, SZ_256M))
+		return false;
+	if (addr >= ALIGN(MODULES_END, SZ_256M))
+		return false;
+#else
 	if (addr < ALIGN_DOWN(VMALLOC_START, SZ_256M))
 		return false;
 	if (addr >= ALIGN(VMALLOC_END, SZ_256M))
 		return false;
+#endif
 	return true;
 }