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authorNick Desaulniers <ndesaulniers@google.com>2021-09-10 16:40:38 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-09-13 10:18:28 -0700
commit76ae847497bc5207c479de5e2ac487270008b19b (patch)
treec3e7b9abcfe6a59f77b29798859bdd3707d433e8 /Documentation
parent2d338201d5311bcd79d42f66df4cecbcbc5f4f2c (diff)
Documentation: raise minimum supported version of GCC to 5.1
commit fad7cd3310db ("nbd: add the check to prevent overflow in __nbd_ioctl()") raised an issue from the fallback helpers added in commit f0907827a8a9 ("compiler.h: enable builtin overflow checkers and add fallback code") Specifically, the helpers for checking whether the results of a multiplication overflowed (__unsigned_mul_overflow, __signed_add_overflow) use the division operator when !COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW. This is problematic for 64b operands on 32b hosts. Also, because the macro is type agnostic, it is very difficult to write a similarly type generic macro that dispatches to one of: * div64_s64 * div64_u64 * div_s64 * div_u64 Raising the minimum supported versions allows us to remove all of the fallback helpers for !COMPILER_HAS_GENERIC_BUILTIN_OVERFLOW, instead dispatching the compiler builtins. arm64 has already raised the minimum supported GCC version to 5.1, do this for all targets now. See the link below for the previous discussion. Link: https://lore.kernel.org/all/20210909182525.372ee687@canb.auug.org.au/ Link: https://lore.kernel.org/lkml/CAK7LNASs6dvU6D3jL2GG3jW58fXfaj6VNOe55NJnTB8UPuk2pA@mail.gmail.com/ Link: https://github.com/ClangBuiltLinux/linux/issues/1438 Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Reported-by: Nathan Chancellor <nathan@kernel.org> Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/process/changes.rst2
1 files changed, 1 insertions, 1 deletions
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