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Subject[PATCH AUTOSEL 5.4 316/350] int128: move __uint128_t compiler test to Kconfig
Date
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 <yamada.masahiro@socionext.com>
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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