Thread (3 messages) 3 messages, 2 authors, 2019-12-19
STALE2384d

[PATCH AUTOSEL 5.4 316/350] int128: move __uint128_t compiler test to Kconfig

From: Sasha Levin <sashal@kernel.org>
Date: 2019-12-10 21:13:22
Also in: linux-crypto, linux-riscv, lkml, stable
Subsystem: arm64 port (aarch64 architecture), asymmetric keys - ecdsa, crypto api, library code, risc-v architecture, the rest, ubsan, x86 architecture (32-bit and 64-bit) · Maintainers: Catalin Marinas, Will Deacon, Lukas Wunner, Ignat Korchagin, Herbert Xu, "David S. Miller", Andrew Morton, Paul Walmsley, Palmer Dabbelt, Albert Ou, Linus Torvalds, Kees Cook, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen

From: Ard Biesheuvel <ardb@kernel.org>

[ Upstream commit c12d3362a74bf0cd9e1d488918d40607b62a3104 ]

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 <redacted>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/arm64/Kconfig | 2 +-
 arch/riscv/Kconfig | 2 +-
 arch/x86/Kconfig   | 2 +-
 crypto/ecc.c       | 2 +-
 init/Kconfig       | 4 ++++
 lib/ubsan.c        | 2 +-
 lib/ubsan.h        | 2 +-
 7 files changed, 10 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 3f047afb982c8..54c38c9cab88a 100644
--- 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
index 8eebbc8860bbd..75a6c91176221 100644
--- 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
index 8ef85139553f5..f2aed8012e9c0 100644
--- 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
index dfe114bc0c4af..6e6aab6c987c2 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 b4daad2bac233..020526f681c03 100644
--- 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
index 0c4681118fcd2..fc552d524ef77 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 b8fa83864467f..7b56c09473a98 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


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