int128: fix __uint128_t compiler test in Kconfig

The support for __uint128_t is dependent on the target bit size.

GCC that defaults to the 32-bit can still build the 64-bit kernel
with -m64 flag passed.

However, $(cc-option,-D__SIZEOF_INT128__=0) is evaluated against the
default machine bit, which may not match to the kernel it is building.

Theoretically, this could be evaluated separately for 64BIT/32BIT.

  config CC_HAS_INT128
          bool
          default !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) if 64BIT
          default !$(cc-option,$(m32-flag) -D__SIZEOF_INT128__=0)

I simplified it more because the 32-bit compiler is unlikely to support
__uint128_t.

Fixes: c12d3362a74b ("int128: move __uint128_t compiler test to Kconfig")
Reported-by: George Spelvin <lkml@sdf.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: George Spelvin <lkml@sdf.org>

diff --git a/init/Kconfig b/init/Kconfig
index 20a6ac33761c98a6bb7466d5ec1a5e476b1eddda..4f717bfdbfe2d1e15fa65ef5357b4fd20bdd70f5 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -767,8 +767,7 @@ config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
        bool
 
 config CC_HAS_INT128
-       def_bool y
-       depends on !$(cc-option,-D__SIZEOF_INT128__=0)
+       def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT
 
 #
 # For architectures that know their GCC __int128 support is sound