Messages in this thread | | | Date | Fri, 10 Sep 2021 16:40:37 -0700 | Subject | [PATCH 00/10] raise minimum GCC version to 5.1 | From | Nick Desaulniers <> |
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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.
Additional patches cleaning up a few obsolete version checks.
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
Nick Desaulniers (10): Documentation: raise minimum supported version of GCC to 5.1 compiler.h: drop fallback overflow checkers mm/ksm: remove old GCC 4.9+ check Kconfig.debug: drop GCC 5+ version check for DWARF5 riscv: remove Kconfig check for GCC version for ARCH_RV64I powerpc: remove GCC version check for UPD_CONSTR arm64: remove GCC version check for ARCH_SUPPORTS_INT128 Makefile: drop GCC < 5 -fno-var-tracking-assignments workaround compiler-gcc.h: drop checks for older GCC versions vmlinux.lds.h: remove old check for GCC 4.9
Documentation/process/changes.rst | 2 +- Makefile | 6 -- arch/arm64/Kconfig | 2 +- arch/powerpc/include/asm/asm-const.h | 10 -- arch/riscv/Kconfig | 2 +- include/asm-generic/vmlinux.lds.h | 4 - include/linux/compiler-clang.h | 13 --- include/linux/compiler-gcc.h | 8 +- include/linux/overflow.h | 138 +------------------------- lib/Kconfig.debug | 2 +- mm/ksm.c | 2 - scripts/min-tool-version.sh | 8 +- tools/include/linux/compiler-gcc.h | 8 +- tools/include/linux/overflow.h | 140 +-------------------------- 14 files changed, 13 insertions(+), 332 deletions(-)
base-commit: 2d338201d5311bcd79d42f66df4cecbcbc5f4f2c -- 2.33.0.309.g3052b89438-goog
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