Binutils-2.38 and GCC-12.1.0 bump[0] default ISA spec to newer version
20191213 which moves some instructions from the I extension to the
Zicsr and Zifencei extensions. So if one of the binutils and GCC exceeds
that version, we should turn on TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI
to cope with the new changes.
The case of clang is special[1][2], where older clang versions (<17) need
to be rolled back to old ISA spec to fix it. And the less common case,
since older GCC versions (<11.1.0) did not support zicsr and zifencei
extension for -march, also requires a fallback to cope with it.
For more information, please refer to:
commit 6df2a016c0c8 ("riscv: fix build with binutils 2.38")
commit e89c2e815e76 ("riscv: Handle zicsr/zifencei issues between clang and binutils")
Link: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=98416dbb0a62579d4a7a4a76bab51b5b52fec2cd [0]
Link: https://lore.kernel.org/all/20230308220842.1231003-1-conor@xxxxxxxxxx [1]
Link: https://lore.kernel.org/all/20230223220546.52879-1-conor@xxxxxxxxxx [2]
Link: https://lore.kernel.org/all/20230725170405.251011-1-xingmingzheng@xxxxxxxxxxx
Signed-off-by: Mingzheng Xing <xingmingzheng@xxxxxxxxxxx>
---
v2:
- Update the Kconfig help text and commit message.
- Add considerations for low version gcc case.
Sorry for the formatting error on my mailing list reply.
arch/riscv/Kconfig | 23 +++++++++++++----------
1 file changed, 13 insertions(+), 10 deletions(-)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 4c07b9189c86..08afd47de157 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -570,24 +570,27 @@ config TOOLCHAIN_HAS_ZIHINTPAUSE
config TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI
def_bool y
# https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=aed44286efa8ae8717a77d94b51ac3614e2ca6dc
- depends on AS_IS_GNU && AS_VERSION >= 23800
+ # https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=98416dbb0a62579d4a7a4a76bab51b5b52fec2cd
+ depends on GCC_VERSION >= 120100 || (AS_IS_GNU && AS_VERSION >= 23800)
help
- Newer binutils versions default to ISA spec version 20191213 which
- moves some instructions from the I extension to the Zicsr and Zifencei
- extensions.
+ Binutils-2.38 and GCC-12.1.0 bump default ISA spec to newer version
+ 20191213 which moves some instructions from the I extension to the
+ Zicsr and Zifencei extensions.
config TOOLCHAIN_NEEDS_OLD_ISA_SPEC
def_bool y
depends on TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI
# https://github.com/llvm/llvm-project/commit/22e199e6afb1263c943c0c0d4498694e15bf8a16
- depends on CC_IS_CLANG && CLANG_VERSION < 170000
+ # https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=b03be74bad08c382da47e048007a78fa3fb4ef49
+ depends on (CC_IS_CLANG && CLANG_VERSION < 170000) || \
+ (CC_IS_GCC && GCC_VERSION < 110100)
help
- Certain versions of clang do not support zicsr and zifencei via -march
- but newer versions of binutils require it for the reasons noted in the
- help text of CONFIG_TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI. This
+ Certain versions of clang (or GCC) do not support zicsr and zifencei via
+ -march but newer versions of binutils require it for the reasons noted
+ in the help text of CONFIG_TOOLCHAIN_NEEDS_EXPLICIT_ZICSR_ZIFENCEI. This
option causes an older ISA spec compatible with these older versions
- of clang to be passed to GAS, which has the same result as passing zicsr
- and zifencei to -march.
+ of clang (or GCC) to be passed to GAS, which has the same result as
+ passing zicsr and zifencei to -march.
config FPU
bool "FPU support"
--
2.34.1
