int128: move __uint128_t compiler test to Kconfig

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. Cc: Masahiro Yamada <[email protected]> Signed-off-by: Ard Biesheuvel <[email protected]> Signed-off-by: Herbert Xu <[email protected]>
soumdtt · Nov 17, 2019 · c12d336 · c12d336
1 parent a11d055
commit c12d336
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Showing 7 changed files with 10 additions and 6 deletions.
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
@@ -67,7 +67,7 @@ config ARM64
 	select ARCH_USE_QUEUED_SPINLOCKS
 	select ARCH_SUPPORTS_MEMORY_FAILURE
 	select ARCH_SUPPORTS_ATOMIC_RMW
-	select ARCH_SUPPORTS_INT128 if GCC_VERSION >= 50000 || CC_IS_CLANG
+	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && (GCC_VERSION >= 50000 || CC_IS_CLANG)
 	select ARCH_SUPPORTS_NUMA_BALANCING
 	select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT
 	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
@@ -164,7 +164,7 @@ config ARCH_RV32I
 config ARCH_RV64I
 	bool "RV64I"
 	select 64BIT
-	select ARCH_SUPPORTS_INT128 if GCC_VERSION >= 50000
+	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && GCC_VERSION >= 50000
 	select HAVE_FUNCTION_TRACER
 	select HAVE_FUNCTION_GRAPH_TRACER
 	select HAVE_FTRACE_MCOUNT_RECORD

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
@@ -24,7 +24,7 @@ config X86_64
 	depends on 64BIT
 	# Options that are inherently 64-bit kernel only:
 	select ARCH_HAS_GIGANTIC_PAGE
-	select ARCH_SUPPORTS_INT128
+	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
 	select ARCH_USE_CMPXCHG_LOCKREF
 	select HAVE_ARCH_SOFT_DIRTY
 	select MODULES_USE_ELF_RELA

diff --git 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
@@ -785,6 +785,10 @@ config ARCH_SUPPORTS_NUMA_BALANCING
 config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
 	bool
 
+config CC_HAS_INT128
+	def_bool y
+	depends on !$(cc-option,-D__SIZEOF_INT128__=0)
+
 #
 # For architectures that know their GCC __int128 support is sound
 #

diff --git 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
@@ -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