x86/boot/compressed: Enable -Wundef

A discussion around -Wundef showed that there were still a few boolean
Kconfigs where #if was used rather than #ifdef to guard different code.
Kconfig doesn't define boolean configs, which can result in -Wundef
warnings.

arch/x86/boot/compressed/Makefile resets the CFLAGS used for this
directory, and doesn't re-enable -Wundef as the top level Makefile does.
If re-added, with RANDOMIZE_BASE and X86_NEED_RELOCS disabled, the
following warnings are visible.

  arch/x86/boot/compressed/misc.h:82:5: warning: 'CONFIG_RANDOMIZE_BASE'
  is not defined, evaluates to 0 [-Wundef]
      ^
  arch/x86/boot/compressed/misc.c:175:5: warning: 'CONFIG_X86_NEED_RELOCS'
  is not defined, evaluates to 0 [-Wundef]
      ^

Simply fix these and re-enable this warning for this directory.

Suggested-by: Nathan Chancellor <nathan@kernel.org>
Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20210422190450.3903999-1-ndesaulniers@google.com

diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 2a29752..431bf7f 100644 (file)
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -30,6 +30,7 @@ targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma \
 
 KBUILD_CFLAGS := -m$(BITS) -O2
 KBUILD_CFLAGS += -fno-strict-aliasing -fPIE
+KBUILD_CFLAGS += -Wundef
 KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
 cflags-$(CONFIG_X86_32) := -march=i386
 cflags-$(CONFIG_X86_64) := -mcmodel=small -mno-red-zone

diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index dde042f..743f13e 100644 (file)
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -172,7 +172,7 @@ void __puthex(unsigned long value)
        }
 }
 
-#if CONFIG_X86_NEED_RELOCS
+#ifdef CONFIG_X86_NEED_RELOCS
 static void handle_relocations(void *output, unsigned long output_len,
                               unsigned long virt_addr)
 {

diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index e5612f0..3113925 100644 (file)
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -79,7 +79,7 @@ struct mem_vector {
        u64 size;
 };
 
-#if CONFIG_RANDOMIZE_BASE
+#ifdef CONFIG_RANDOMIZE_BASE
 /* kaslr.c */
 void choose_random_location(unsigned long input,
                            unsigned long input_size,