Messages in this thread | | | Date | Thu, 27 Jul 2023 03:34:16 +0800 | Subject | Re: [PATCH v2] riscv: Handle zicsr/zifencei issue between gcc and binutils | From | Mingzheng Xing <> |
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On 7/27/23 02:02, Conor Dooley wrote: > On Thu, Jul 27, 2023 at 01:45:24AM +0800, Mingzheng Xing wrote: >> 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 > Can you provide a link to explain why this is 11.1.0 in particular?
Okay, I can add it in commit message. gcc-11.1.0 is particular because it add support zicsr and zifencei extension for -march[1].
Link: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=b03be74bad08c382da47e048007a78fa3fb4ef49 [1]
>> 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@kernel.org [1] >> Link: https://lore.kernel.org/all/20230223220546.52879-1-conor@kernel.org [2] >> Link: https://lore.kernel.org/all/20230725170405.251011-1-xingmingzheng@iscas.ac.cn > This shouldn't be here, you don't link to your old patches.
My bad, I will fix it.
> >> Signed-off-by: Mingzheng Xing <xingmingzheng@iscas.ac.cn> > This is still broken for: > CONFIG_CLANG_VERSION=0 > CONFIG_AS_IS_GNU=y > CONFIG_AS_VERSION=23500 > CONFIG_LD_IS_BFD=y > CONFIG_LD_VERSION=23500
Do you mean that these CONFIG_* will cause kernel compilation errors when paired with certain versions of GCC? Or perhaps I misunderstood your meaning.
> > Please don't post a v2 while there is still ongoing discussion on the > v1. I'll try to reply here tomorrow with a diff you can fold in to fix > the problem.
Okay, thanks for your review.
> Thanks, > Conor. > >> --- >> >> 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 >> >> >> _______________________________________________ >> linux-riscv mailing list >> linux-riscv@lists.infradead.org >> http://lists.infradead.org/mailman/listinfo/linux-riscv
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