In order to use 128-bit integer arithmetic in C code, the architecture
needs to have declared support for it by setting ARCH_SUPPORTS_INT128,
and it requires a version of the toolchain that supports this at build
time. This is why all existing tests for ARCH_SUPPORTS_INT128 also test
whether __SIZEOF_INT128__ is defined, since this is only the case for
compilers that can support 128-bit integers.
Let's fold this additional test into the Kconfig declaration of
ARCH_SUPPORTS_INT128 so that we can also use the symbol in Makefiles,
e.g., to decide whether a certain object needs to be included in the
first place.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
crypto/ecc.c | 2 +-
init/Kconfig | 1 +
lib/ubsan.c | 2 +-
lib/ubsan.h | 2 +-
4 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/crypto/ecc.c b/crypto/ecc.c
index dfe114bc0c4a..6e6aab6c987c 100644
--- a/crypto/ecc.c
+++ b/crypto/ecc.c
@@ -336,7 +336,7 @@ static u64 vli_usub(u64 *result, const u64 *left, u64 right,
static uint128_t mul_64_64(u64 left, u64 right)
{
uint128_t result;
-#if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__)
+#if defined(CONFIG_ARCH_SUPPORTS_INT128)
unsigned __int128 m = (unsigned __int128)left * right;
result.m_low = m;
diff --git a/init/Kconfig b/init/Kconfig
index bd7d650d4a99..e66f64a26d7d 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -785,6 +785,7 @@ config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
#
config ARCH_SUPPORTS_INT128
bool
+ depends on !$(cc-option,-D__SIZEOF_INT128__=0)
# For architectures that (ab)use NUMA to represent different memory regions
# all cpu-local but of different latencies, such as SuperH.
diff --git a/lib/ubsan.c b/lib/ubsan.c
index e7d31735950d..b652cc14dd60 100644
--- a/lib/ubsan.c
+++ b/lib/ubsan.c
@@ -119,7 +119,7 @@ static void val_to_string(char *str, size_t size, struct type_descriptor *type,
{
if (type_is_int(type)) {
if (type_bit_width(type) == 128) {
-#if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__)
+#if defined(CONFIG_ARCH_SUPPORTS_INT128)
u_max val = get_unsigned_val(type, value);
scnprintf(str, size, "0x%08x%08x%08x%08x",
diff --git a/lib/ubsan.h b/lib/ubsan.h
index b8fa83864467..7b56c09473a9 100644
--- a/lib/ubsan.h
+++ b/lib/ubsan.h
@@ -78,7 +78,7 @@ struct invalid_value_data {
struct type_descriptor *type;
};
-#if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__)
+#if defined(CONFIG_ARCH_SUPPORTS_INT128)
typedef __int128 s_max;
typedef unsigned __int128 u_max;
#else
--
2.20.1
