kconfig_has_kaslr: drop CONFIG_RELOCATABLE requirement

CONFIG_RELOCATABLE does not exist on s390x (or arm64, riscv64, etc.).
Requiring it caused proc-config and boot-config to falsely signal
KASLR disabled on those arches, suppressing legitimate proc-kallsyms
results via the inject_kaslr_defaults tiebreak. On x86/x86_64,
CONFIG_RANDOMIZE_BASE depends on CONFIG_RELOCATABLE anyway, so
checking CONFIG_RANDOMIZE_BASE alone is equivalent everywhere.

Author: bcoles

src/components/boot-config.c

@@ -75,8 +75,9 @@ static unsigned long get_kernel_addr_boot_config(FILE *fp) {
   if (kconfig_has_kaslr(fp))
     return 0;
 
-  printf("[.] Kernel appears to have been compiled without both "
-         "CONFIG_RELOCATABLE and CONFIG_RANDOMIZE_BASE\n");
+  printf(
+      "[.] Kernel appears to have been compiled without CONFIG_RANDOMIZE_BASE"
+      " (KASLR not compiled in)\n");
 
   return (unsigned long)KERNEL_TEXT_DEFAULT;
 }

src/components/proc-config.c

@@ -116,8 +116,9 @@ static unsigned long get_kernel_addr_proc_config(FILE *fp) {
   if (kconfig_has_kaslr(fp))
     return 0;
 
-  printf("[.] Kernel appears to have been compiled without both "
-         "CONFIG_RELOCATABLE and CONFIG_RANDOMIZE_BASE\n");
+  printf(
+      "[.] Kernel appears to have been compiled without CONFIG_RANDOMIZE_BASE"
+      " (KASLR not compiled in)\n");
 
   return (unsigned long)KERNEL_TEXT_DEFAULT;
 }

src/include/kconfig.h

@@ -76,11 +76,16 @@ static unsigned long get_kconfig_page_offset(FILE *fp) {
 }
 
 /* Check if the kernel was compiled with KASLR support
- * (CONFIG_RELOCATABLE=y and CONFIG_RANDOMIZE_BASE=y).
- * Returns 1 if KASLR is enabled, 0 otherwise. */
+ * (CONFIG_RANDOMIZE_BASE=y).
+ *
+ * On x86/x86_64, CONFIG_RANDOMIZE_BASE has CONFIG_RELOCATABLE as a hard
+ * Kconfig dependency, so checking CONFIG_RANDOMIZE_BASE alone is sufficient.
+ * On all other arches (arm64, s390x, riscv64, powerpc, mips, ...) there is
+ * no CONFIG_RELOCATABLE; KASLR requires only CONFIG_RANDOMIZE_BASE.
+ *
+ * Returns 1 if KASLR is compiled in, 0 otherwise. */
 static int kconfig_has_kaslr(FILE *fp) {
-  return is_kconfig_set(fp, "CONFIG_RELOCATABLE") &&
-         is_kconfig_set(fp, "CONFIG_RANDOMIZE_BASE");
+  return is_kconfig_set(fp, "CONFIG_RANDOMIZE_BASE");
 }
 
 #endif /* KASLD_KCONFIG_H */