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-rw-r--r--Documentation/admin-guide/README.rst2
-rw-r--r--Documentation/process/changes.rst2
-rw-r--r--Documentation/translations/zh_CN/admin-guide/README.rst2
-rw-r--r--Documentation/translations/zh_TW/admin-guide/README.rst2
-rw-r--r--Makefile6
-rw-r--r--arch/arm64/Kconfig2
-rw-r--r--arch/powerpc/include/asm/asm-const.h10
-rw-r--r--arch/riscv/Kconfig2
-rw-r--r--include/asm-generic/vmlinux.lds.h4
-rw-r--r--include/linux/compiler-clang.h13
-rw-r--r--include/linux/compiler-gcc.h8
-rw-r--r--include/linux/compiler_attributes.h24
-rw-r--r--include/linux/overflow.h138
-rw-r--r--lib/Kconfig.debug2
-rw-r--r--mm/ksm.c2
-rwxr-xr-xscripts/min-tool-version.sh8
-rw-r--r--tools/include/linux/compiler-gcc.h8
-rw-r--r--tools/include/linux/overflow.h140
18 files changed, 16 insertions, 359 deletions
diff --git a/Documentation/admin-guide/README.rst b/Documentation/admin-guide/README.rst
index 35314b63008c..caa3c09a5c3f 100644
--- a/Documentation/admin-guide/README.rst
+++ b/Documentation/admin-guide/README.rst
@@ -259,7 +259,7 @@ Configuring the kernel
Compiling the kernel
--------------------
- - Make sure you have at least gcc 4.9 available.
+ - Make sure you have at least gcc 5.1 available.
For more information, refer to :ref:`Documentation/process/changes.rst <changes>`.
Please note that you can still run a.out user programs with this kernel.
diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst
index d3a8557b66a1..e35ab74a0f80 100644
--- a/Documentation/process/changes.rst
+++ b/Documentation/process/changes.rst
@@ -29,7 +29,7 @@ you probably needn't concern yourself with pcmciautils.
====================== =============== ========================================
Program Minimal version Command to check the version
====================== =============== ========================================
-GNU C 4.9 gcc --version
+GNU C 5.1 gcc --version
Clang/LLVM (optional) 10.0.1 clang --version
GNU make 3.81 make --version
binutils 2.23 ld -v
diff --git a/Documentation/translations/zh_CN/admin-guide/README.rst b/Documentation/translations/zh_CN/admin-guide/README.rst
index 669a022f6817..980eb20521cf 100644
--- a/Documentation/translations/zh_CN/admin-guide/README.rst
+++ b/Documentation/translations/zh_CN/admin-guide/README.rst
@@ -223,7 +223,7 @@ Linux内核5.x版本 <http://kernel.org/>
编译内核
---------
- - 确保您至少有gcc 4.9可用。
+ - 确保您至少有gcc 5.1可用。
有关更多信息，请参阅 :ref:`Documentation/process/changes.rst <changes>` 。
请注意，您仍然可以使用此内核运行a.out用户程序。
diff --git a/Documentation/translations/zh_TW/admin-guide/README.rst b/Documentation/translations/zh_TW/admin-guide/README.rst
index b752e50359e6..6ce97edbab37 100644
--- a/Documentation/translations/zh_TW/admin-guide/README.rst
+++ b/Documentation/translations/zh_TW/admin-guide/README.rst
@@ -226,7 +226,7 @@ Linux內核5.x版本 <http://kernel.org/>
編譯內核
---------
- - 確保您至少有gcc 4.9可用。
+ - 確保您至少有gcc 5.1可用。
有關更多信息，請參閱 :ref:`Documentation/process/changes.rst <changes>` 。
請注意，您仍然可以使用此內核運行a.out用戶程序。
diff --git a/Makefile b/Makefile
index 7cfe4ff36f44..34a0afc3a8eb 100644
--- a/Makefile
+++ b/Makefile
@@ -849,12 +849,6 @@ endif
DEBUG_CFLAGS :=
-# Workaround for GCC versions < 5.0
-# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61801
-ifdef CONFIG_CC_IS_GCC
-DEBUG_CFLAGS += $(call cc-ifversion, -lt, 0500, $(call cc-option, -fno-var-tracking-assignments))
-endif
-
ifdef CONFIG_DEBUG_INFO
ifdef CONFIG_DEBUG_INFO_SPLIT
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 077f2ec4eeb2..5c7ae4c3954b 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -86,7 +86,7 @@ config ARM64
select ARCH_SUPPORTS_LTO_CLANG_THIN
select ARCH_SUPPORTS_CFI_CLANG
select ARCH_SUPPORTS_ATOMIC_RMW
- select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && (GCC_VERSION >= 50000 || CC_IS_CLANG)
+ select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
select ARCH_SUPPORTS_NUMA_BALANCING
select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT
select ARCH_WANT_DEFAULT_BPF_JIT
diff --git a/arch/powerpc/include/asm/asm-const.h b/arch/powerpc/include/asm/asm-const.h
index 0ce2368bd20f..dbfa5e1e3198 100644
--- a/arch/powerpc/include/asm/asm-const.h
+++ b/arch/powerpc/include/asm/asm-const.h
@@ -12,16 +12,6 @@
# define ASM_CONST(x) __ASM_CONST(x)
#endif
-/*
- * Inline assembly memory constraint
- *
- * GCC 4.9 doesn't properly handle pre update memory constraint "m<>"
- *
- */
-#if defined(GCC_VERSION) && GCC_VERSION < 50000
-#define UPD_CONSTR ""
-#else
#define UPD_CONSTR "<>"
-#endif
#endif /* _ASM_POWERPC_ASM_CONST_H */
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index c3f3fd583e04..301a54233c7e 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -236,7 +236,7 @@ config ARCH_RV32I
config ARCH_RV64I
bool "RV64I"
select 64BIT
- select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 && GCC_VERSION >= 50000
+ select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && MMU && $(cc-option,-fpatchable-function-entry=8)
select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index aa50bf2959fe..f2984af2b85b 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -116,11 +116,7 @@
* GCC 4.5 and later have a 32 bytes section alignment for structures.
* Except GCC 4.9, that feels the need to align on 64 bytes.
*/
-#if __GNUC__ == 4 && __GNUC_MINOR__ == 9
-#define STRUCT_ALIGNMENT 64
-#else
#define STRUCT_ALIGNMENT 32
-#endif
#define STRUCT_ALIGN() . = ALIGN(STRUCT_ALIGNMENT)
/*
diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h
index 49b0ac8b6fd3..3c4de9b6c6e3 100644
--- a/include/linux/compiler-clang.h
+++ b/include/linux/compiler-clang.h
@@ -62,19 +62,6 @@
#define __no_sanitize_coverage
#endif
-/*
- * Not all versions of clang implement the type-generic versions
- * of the builtin overflow checkers. Fortunately, clang implements
- * __has_builtin allowing us to avoid awkward version
- * checks. Unfortunately, we don't know which version of gcc clang
- * pretends to be, so the macro may or may not be defined.
- */
-#if __has_builtin(__builtin_mul_overflow) && \
- __has_builtin(__builtin_add_overflow) && \
- __has_builtin(__builtin_sub_overflow)
-#define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1
-#endif
-
#if __has_feature(shadow_call_stack)
# define __noscs __attribute__((__no_sanitize__("shadow-call-stack")))
#endif
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index 21c36b69eb06..bd2b881c6b63 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -95,10 +95,8 @@
#if GCC_VERSION >= 70000
#define KASAN_ABI_VERSION 5
-#elif GCC_VERSION >= 50000
+#else
#define KASAN_ABI_VERSION 4
-#elif GCC_VERSION >= 40902
-#define KASAN_ABI_VERSION 3
#endif
#if __has_attribute(__no_sanitize_address__)
@@ -125,10 +123,6 @@
#define __no_sanitize_coverage
#endif
-#if GCC_VERSION >= 50100
-#define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1
-#endif
-
/*
* Turn individual warnings and errors on and off locally, depending
* on version.
diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h
index 8f2106e9e5c1..e6ec63403965 100644
--- a/include/linux/compiler_attributes.h
+++ b/include/linux/compiler_attributes.h
@@ -21,29 +21,6 @@
*/
/*
- * __has_attribute is supported on gcc >= 5, clang >= 2.9 and icc >= 17.
- * In the meantime, to support gcc < 5, we implement __has_attribute
- * by hand.
- */
-#ifndef __has_attribute
-# define __has_attribute(x) __GCC4_has_attribute_##x
-# define __GCC4_has_attribute___assume_aligned__ 1
-# define __GCC4_has_attribute___copy__ 0
-# define __GCC4_has_attribute___designated_init__ 0
-# define __GCC4_has_attribute___error__ 1
-# define __GCC4_has_attribute___externally_visible__ 1
-# define __GCC4_has_attribute___no_caller_saved_registers__ 0
-# define __GCC4_has_attribute___noclone__ 1
-# define __GCC4_has_attribute___no_profile_instrument_function__ 0
-# define __GCC4_has_attribute___nonstring__ 0
-# define __GCC4_has_attribute___no_sanitize_address__ 1
-# define __GCC4_has_attribute___no_sanitize_undefined__ 1
-# define __GCC4_has_attribute___no_sanitize_coverage__ 0
-# define __GCC4_has_attribute___fallthrough__ 0
-# define __GCC4_has_attribute___warning__ 1
-#endif
-
-/*
* gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-alias-function-attribute
*/
#define __alias(symbol) __attribute__((__alias__(#symbol)))
@@ -77,7 +54,6 @@
* compiler should see some alignment anyway, when the return value is
* massaged by 'flags = ptr & 3; ptr &= ~3;').
*
- * Optional: only supported since gcc >= 4.9
* Optional: not supported by icc
*
* gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-assume_005faligned-function-attribute
diff --git a/include/linux/overflow.h b/include/linux/overflow.h
index 0f12345c21fb..4669632bd72b 100644
--- a/include/linux/overflow.h
+++ b/include/linux/overflow.h
@@ -6,12 +6,9 @@
#include <linux/limits.h>
/*
- * In the fallback code below, we need to compute the minimum and
- * maximum values representable in a given type. These macros may also
- * be useful elsewhere, so we provide them outside the
- * COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW block.
- *
- * It would seem more obvious to do something like
+ * We need to compute the minimum and maximum values representable in a given
+ * type. These macros may also be useful elsewhere. It would seem more obvious
+ * to do something like:
*
* #define type_min(T) (T)(is_signed_type(T) ? (T)1 << (8*sizeof(T)-1) : 0)
* #define type_max(T) (T)(is_signed_type(T) ? ((T)1 << (8*sizeof(T)-1)) - 1 : ~(T)0)
@@ -54,7 +51,6 @@ static inline bool __must_check __must_check_overflow(bool overflow)
return unlikely(overflow);
}
-#ifdef COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW
/*
* For simplicity and code hygiene, the fallback code below insists on
* a, b and *d having the same type (similar to the min() and max()
@@ -90,134 +86,6 @@ static inline bool __must_check __must_check_overflow(bool overflow)
__builtin_mul_overflow(__a, __b, __d); \
}))
-#else
-
-
-/* Checking for unsigned overflow is relatively easy without causing UB. */
-#define __unsigned_add_overflow(a, b, d) ({ \
- typeof(a) __a = (a); \
- typeof(b) __b = (b); \
- typeof(d) __d = (d); \
- (void) (&__a == &__b); \
- (void) (&__a == __d); \
- *__d = __a + __b; \
- *__d < __a; \
-})
-#define __unsigned_sub_overflow(a, b, d) ({ \
- typeof(a) __a = (a); \
- typeof(b) __b = (b); \
- typeof(d) __d = (d); \
- (void) (&__a == &__b); \
- (void) (&__a == __d); \
- *__d = __a - __b; \
- __a < __b; \
-})
-/*
- * If one of a or b is a compile-time constant, this avoids a division.
- */
-#define __unsigned_mul_overflow(a, b, d) ({ \
- typeof(a) __a = (a); \
- typeof(b) __b = (b); \
- typeof(d) __d = (d); \
- (void) (&__a == &__b); \
- (void) (&__a == __d); \
- *__d = __a * __b; \
- __builtin_constant_p(__b) ? \
- __b > 0 && __a > type_max(typeof(__a)) / __b : \
- __a > 0 && __b > type_max(typeof(__b)) / __a; \
-})
-
-/*
- * For signed types, detecting overflow is much harder, especially if
- * we want to avoid UB. But the interface of these macros is such that
- * we must provide a result in *d, and in fact we must produce the
- * result promised by gcc's builtins, which is simply the possibly
- * wrapped-around value. Fortunately, we can just formally do the
- * operations in the widest relevant unsigned type (u64) and then
- * truncate the result - gcc is smart enough to generate the same code
- * with and without the (u64) casts.
- */
-
-/*
- * Adding two signed integers can overflow only if they have the same
- * sign, and overflow has happened iff the result has the opposite
- * sign.
- */
-#define __signed_add_overflow(a, b, d) ({ \
- typeof(a) __a = (a); \
- typeof(b) __b = (b); \
- typeof(d) __d = (d); \
- (void) (&__a == &__b); \
- (void) (&__a == __d); \
- *__d = (u64)__a + (u64)__b; \
- (((~(__a ^ __b)) & (*__d ^ __a)) \
- & type_min(typeof(__a))) != 0; \
-})
-
-/*
- * Subtraction is similar, except that overflow can now happen only
- * when the signs are opposite. In this case, overflow has happened if
- * the result has the opposite sign of a.
- */
-#define __signed_sub_overflow(a, b, d) ({ \
- typeof(a) __a = (a); \
- typeof(b) __b = (b); \
- typeof(d) __d = (d); \
- (void) (&__a == &__b); \
- (void) (&__a == __d); \
- *__d = (u64)__a - (u64)__b; \
- ((((__a ^ __b)) & (*__d ^ __a)) \
- & type_min(typeof(__a))) != 0; \
-})
-
-/*
- * Signed multiplication is rather hard. gcc always follows C99, so
- * division is truncated towards 0. This means that we can write the
- * overflow check like this:
- *
- * (a > 0 && (b > MAX/a || b < MIN/a)) ||
- * (a < -1 && (b > MIN/a || b < MAX/a) ||
- * (a == -1 && b == MIN)
- *
- * The redundant casts of -1 are to silence an annoying -Wtype-limits
- * (included in -Wextra) warning: When the type is u8 or u16, the
- * __b_c_e in check_mul_overflow obviously selects
- * __unsigned_mul_overflow, but unfortunately gcc still parses this
- * code and warns about the limited range of __b.
- */
-
-#define __signed_mul_overflow(a, b, d) ({ \
- typeof(a) __a = (a); \
- typeof(b) __b = (b); \
- typeof(d) __d = (d); \
- typeof(a) __tmax = type_max(typeof(a)); \
- typeof(a) __tmin = type_min(typeof(a)); \
- (void) (&__a == &__b); \
- (void) (&__a == __d); \
- *__d = (u64)__a * (u64)__b; \
- (__b > 0 && (__a > __tmax/__b || __a < __tmin/__b)) || \
- (__b < (typeof(__b))-1 && (__a > __tmin/__b || __a < __tmax/__b)) || \
- (__b == (typeof(__b))-1 && __a == __tmin); \
-})
-
-
-#define check_add_overflow(a, b, d) __must_check_overflow( \
- __builtin_choose_expr(is_signed_type(typeof(a)), \
- __signed_add_overflow(a, b, d), \
- __unsigned_add_overflow(a, b, d)))
-
-#define check_sub_overflow(a, b, d) __must_check_overflow( \
- __builtin_choose_expr(is_signed_type(typeof(a)), \
- __signed_sub_overflow(a, b, d), \
- __unsigned_sub_overflow(a, b, d)))
-
-#define check_mul_overflow(a, b, d) __must_check_overflow( \
- __builtin_choose_expr(is_signed_type(typeof(a)), \
- __signed_mul_overflow(a, b, d), \
- __unsigned_mul_overflow(a, b, d)))
-
-#endif /* COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW */
-
/** check_shl_overflow() - Calculate a left-shifted value and check overflow
*
* @a: Value to be shifted
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index ed4a31e34098..d566f601780f 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -295,7 +295,7 @@ config DEBUG_INFO_DWARF4
config DEBUG_INFO_DWARF5
bool "Generate DWARF Version 5 debuginfo"
- depends on GCC_VERSION >= 50000 || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)))
+ depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)))
depends on !DEBUG_INFO_BTF
help
Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
diff --git a/mm/ksm.c b/mm/ksm.c
index 025338128cd9..a5716fdec1aa 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -651,10 +651,8 @@ static void remove_node_from_stable_tree(struct stable_node *stable_node)
* from &migrate_nodes. This will verify that future list.h changes
* don't break STABLE_NODE_DUP_HEAD. Only recent gcc can handle it.
*/
-#if defined(GCC_VERSION) && GCC_VERSION >= 40903
BUILD_BUG_ON(STABLE_NODE_DUP_HEAD <= &migrate_nodes);
BUILD_BUG_ON(STABLE_NODE_DUP_HEAD >= &migrate_nodes + 1);
-#endif
if (stable_node->head == &migrate_nodes)
list_del(&stable_node->list);
diff --git a/scripts/min-tool-version.sh b/scripts/min-tool-version.sh
index 319f92104f56..4edc708baa63 100755
--- a/scripts/min-tool-version.sh
+++ b/scripts/min-tool-version.sh
@@ -17,13 +17,7 @@ binutils)
echo 2.23.0
;;
gcc)
- # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63293
- # https://lore.kernel.org/r/20210107111841.GN1551@shell.armlinux.org.uk
- if [ "$SRCARCH" = arm64 ]; then
- echo 5.1.0
- else
- echo 4.9.0
- fi
+ echo 5.1.0
;;
icc)
# temporary
diff --git a/tools/include/linux/compiler-gcc.h b/tools/include/linux/compiler-gcc.h
index 95c072b70d0e..43d9a46d36f0 100644
--- a/tools/include/linux/compiler-gcc.h
+++ b/tools/include/linux/compiler-gcc.h
@@ -16,9 +16,7 @@
# define __fallthrough __attribute__ ((fallthrough))
#endif
-#if GCC_VERSION >= 40300
-# define __compiletime_error(message) __attribute__((error(message)))
-#endif /* GCC_VERSION >= 40300 */
+#define __compiletime_error(message) __attribute__((error(message)))
/* &a[0] degrades to a pointer: a different type from an array */
#define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
@@ -38,7 +36,3 @@
#endif
#define __printf(a, b) __attribute__((format(printf, a, b)))
#define __scanf(a, b) __attribute__((format(scanf, a, b)))
-
-#if GCC_VERSION >= 50100
-#define COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW 1
-#endif
diff --git a/tools/include/linux/overflow.h b/tools/include/linux/overflow.h
index 8712ff70995f..dcb0c1bf6866 100644
--- a/tools/include/linux/overflow.h
+++ b/tools/include/linux/overflow.h
@@ -5,12 +5,9 @@
#include <linux/compiler.h>
/*
- * In the fallback code below, we need to compute the minimum and
- * maximum values representable in a given type. These macros may also
- * be useful elsewhere, so we provide them outside the
- * COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW block.
- *
- * It would seem more obvious to do something like
+ * We need to compute the minimum and maximum values representable in a given
+ * type. These macros may also be useful elsewhere. It would seem more obvious
+ * to do something like:
*
* #define type_min(T) (T)(is_signed_type(T) ? (T)1 << (8*sizeof(T)-1) : 0)
* #define type_max(T) (T)(is_signed_type(T) ? ((T)1 << (8*sizeof(T)-1)) - 1 : ~(T)0)
@@ -36,8 +33,6 @@
#define type_max(T) ((T)((__type_half_max(T) - 1) + __type_half_max(T)))
#define type_min(T) ((T)((T)-type_max(T)-(T)1))
-
-#ifdef COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW
/*
* For simplicity and code hygiene, the fallback code below insists on
* a, b and *d having the same type (similar to the min() and max()
@@ -73,135 +68,6 @@
__builtin_mul_overflow(__a, __b, __d); \
})
-#else
-
-
-/* Checking for unsigned overflow is relatively easy without causing UB. */
-#define __unsigned_add_overflow(a, b, d) ({ \
- typeof(a) __a = (a); \
- typeof(b) __b = (b); \
- typeof(d) __d = (d); \
- (void) (&__a == &__b); \
- (void) (&__a == __d); \
- *__d = __a + __b; \
- *__d < __a; \
-})
-#define __unsigned_sub_overflow(a, b, d) ({ \
- typeof(a) __a = (a); \
- typeof(b) __b = (b); \
- typeof(d) __d = (d); \
- (void) (&__a == &__b); \
- (void) (&__a == __d); \
- *__d = __a - __b; \
- __a < __b; \
-})
-/*
- * If one of a or b is a compile-time constant, this avoids a division.
- */
-#define __unsigned_mul_overflow(a, b, d) ({ \
- typeof(a) __a = (a); \
- typeof(b) __b = (b); \
- typeof(d) __d = (d); \
- (void) (&__a == &__b); \
- (void) (&__a == __d); \
- *__d = __a * __b; \
- __builtin_constant_p(__b) ? \
- __b > 0 && __a > type_max(typeof(__a)) / __b : \
- __a > 0 && __b > type_max(typeof(__b)) / __a; \
-})
-
-/*
- * For signed types, detecting overflow is much harder, especially if
- * we want to avoid UB. But the interface of these macros is such that
- * we must provide a result in *d, and in fact we must produce the
- * result promised by gcc's builtins, which is simply the possibly
- * wrapped-around value. Fortunately, we can just formally do the
- * operations in the widest relevant unsigned type (u64) and then
- * truncate the result - gcc is smart enough to generate the same code
- * with and without the (u64) casts.
- */
-
-/*
- * Adding two signed integers can overflow only if they have the same
- * sign, and overflow has happened iff the result has the opposite
- * sign.
- */
-#define __signed_add_overflow(a, b, d) ({ \
- typeof(a) __a = (a); \
- typeof(b) __b = (b); \
- typeof(d) __d = (d); \
- (void) (&__a == &__b); \
- (void) (&__a == __d); \
- *__d = (u64)__a + (u64)__b; \
- (((~(__a ^ __b)) & (*__d ^ __a)) \
- & type_min(typeof(__a))) != 0; \
-})
-
-/*
- * Subtraction is similar, except that overflow can now happen only
- * when the signs are opposite. In this case, overflow has happened if
- * the result has the opposite sign of a.
- */
-#define __signed_sub_overflow(a, b, d) ({ \
- typeof(a) __a = (a); \
- typeof(b) __b = (b); \
- typeof(d) __d = (d); \
- (void) (&__a == &__b); \
- (void) (&__a == __d); \
- *__d = (u64)__a - (u64)__b; \
- ((((__a ^ __b)) & (*__d ^ __a)) \
- & type_min(typeof(__a))) != 0; \
-})
-
-/*
- * Signed multiplication is rather hard. gcc always follows C99, so
- * division is truncated towards 0. This means that we can write the
- * overflow check like this:
- *
- * (a > 0 && (b > MAX/a || b < MIN/a)) ||
- * (a < -1 && (b > MIN/a || b < MAX/a) ||
- * (a == -1 && b == MIN)
- *
- * The redundant casts of -1 are to silence an annoying -Wtype-limits
- * (included in -Wextra) warning: When the type is u8 or u16, the
- * __b_c_e in check_mul_overflow obviously selects
- * __unsigned_mul_overflow, but unfortunately gcc still parses this
- * code and warns about the limited range of __b.
- */
-
-#define __signed_mul_overflow(a, b, d) ({ \
- typeof(a) __a = (a); \
- typeof(b) __b = (b); \
- typeof(d) __d = (d); \
- typeof(a) __tmax = type_max(typeof(a)); \
- typeof(a) __tmin = type_min(typeof(a)); \
- (void) (&__a == &__b); \
- (void) (&__a == __d); \
- *__d = (u64)__a * (u64)__b; \
- (__b > 0 && (__a > __tmax/__b || __a < __tmin/__b)) || \
- (__b < (typeof(__b))-1 && (__a > __tmin/__b || __a < __tmax/__b)) || \
- (__b == (typeof(__b))-1 && __a == __tmin); \
-})
-
-
-#define check_add_overflow(a, b, d) \
- __builtin_choose_expr(is_signed_type(typeof(a)), \
- __signed_add_overflow(a, b, d), \
- __unsigned_add_overflow(a, b, d))
-
-#define check_sub_overflow(a, b, d) \
- __builtin_choose_expr(is_signed_type(typeof(a)), \
- __signed_sub_overflow(a, b, d), \
- __unsigned_sub_overflow(a, b, d))
-
-#define check_mul_overflow(a, b, d) \
- __builtin_choose_expr(is_signed_type(typeof(a)), \
- __signed_mul_overflow(a, b, d), \
- __unsigned_mul_overflow(a, b, d))
-
-
-#endif /* COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW */
-
/**
* array_size() - Calculate size of 2-dimensional array.
*
generated by cgit (git 2.34.1) at 2024-05-21 14:58:19 +0000