arm64: move warning about toolchains to archprepare

Commit 987fdfec2410 ("arm64: move --fix-cortex-a53-843419 linker test to
Kconfig") fixed the false-positive warning in the installation step.

Yet, there are some cases where this false-positive is shown. For example,
you can see it when you cross 987fdfec2410 during git-bisect.

  $ git checkout 987fdfec2410^
    [ snip ]
  $ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- defconfig all
    [ snip ]
  $ git checkout v5.13
    [ snip]
  $ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- defconfig all
    [ snip ]
  arch/arm64/Makefile:25: ld does not support --fix-cortex-a53-843419; kernel may be susceptible to erratum

In the stale include/config/auto.config, CONFIG_ARM64_ERRATUM_843419=y
is set without CONFIG_ARM64_LD_HAS_FIX_ERRATUM_843419, so the warning
is displayed while parsing the Makefiles.

Make will restart with the updated include/config/auto.config, hence
CONFIG_ARM64_LD_HAS_FIX_ERRATUM_843419 will be set eventually, but
this warning is a surprise for users.

Commit 25896d073d8a ("x86/build: Fix compiler support check for
CONFIG_RETPOLINE") addressed a similar issue.

Move $(warning ...) out of the parse stage of Makefiles.

The same applies to CONFIG_ARM64_USE_LSE_ATOMICS.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20210801053525.105235-1-masahiroy@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 7bc37d0..7b668db 100644 (file)
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -21,19 +21,11 @@ LDFLAGS_vmlinux             += -shared -Bsymbolic -z notext \
 endif
 
 ifeq ($(CONFIG_ARM64_ERRATUM_843419),y)
-  ifneq ($(CONFIG_ARM64_LD_HAS_FIX_ERRATUM_843419),y)
-$(warning ld does not support --fix-cortex-a53-843419; kernel may be susceptible to erratum)
-  else
+  ifeq ($(CONFIG_ARM64_LD_HAS_FIX_ERRATUM_843419),y)
 LDFLAGS_vmlinux        += --fix-cortex-a53-843419
   endif
 endif
 
-ifeq ($(CONFIG_ARM64_USE_LSE_ATOMICS), y)
-  ifneq ($(CONFIG_ARM64_LSE_ATOMICS), y)
-$(warning LSE atomics not supported by binutils)
-  endif
-endif
-
 cc_has_k_constraint := $(call try-run,echo                             \
        'int main(void) {                                               \
                asm volatile("and w0, w0, %w0" :: "K" (4294967295));    \
@@ -176,6 +168,17 @@ vdso_install:
 
 archprepare:
        $(Q)$(MAKE) $(build)=arch/arm64/tools kapi
+ifeq ($(CONFIG_ARM64_ERRATUM_843419),y)
+  ifneq ($(CONFIG_ARM64_LD_HAS_FIX_ERRATUM_843419),y)
+       @echo "warning: ld does not support --fix-cortex-a53-843419; kernel may be susceptible to erratum" >&2
+  endif
+endif
+ifeq ($(CONFIG_ARM64_USE_LSE_ATOMICS),y)
+  ifneq ($(CONFIG_ARM64_LSE_ATOMICS),y)
+       @echo "warning: LSE atomics not supported by binutils" >&2
+  endif
+endif
+
 
 # We use MRPROPER_FILES and CLEAN_FILES now
 archclean: