linux-stable/scripts/min-tool-version.sh
Nick Desaulniers 76ae847497 Documentation: raise minimum supported version of GCC to 5.1
commit fad7cd3310 ("nbd: add the check to prevent overflow in
__nbd_ioctl()") raised an issue from the fallback helpers added in
commit f0907827a8 ("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>
2021-09-13 10:18:28 -07:00

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#!/bin/sh
# SPDX-License-Identifier: GPL-2.0-only
#
# Print the minimum supported version of the given tool.
# When you raise the minimum version, please update
# Documentation/process/changes.rst as well.
set -e
if [ $# != 1 ]; then
echo "Usage: $0 toolname" >&2
exit 1
fi
case "$1" in
binutils)
echo 2.23.0
;;
gcc)
echo 5.1.0
;;
icc)
# temporary
echo 16.0.3
;;
llvm)
# https://lore.kernel.org/r/YMtib5hKVyNknZt3@osiris/
if [ "$SRCARCH" = s390 ]; then
echo 13.0.0
else
echo 10.0.1
fi
;;
*)
echo "$1: unknown tool" >&2
exit 1
;;
esac