[PW_SID:990331] [RFC] riscv: Use 64-bit variable for output in __get_user_asm - #757
[PW_SID:990331] [RFC] riscv: Use 64-bit variable for output in __get_user_asm#757linux-riscv-bot wants to merge 1 commit into
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After commit f6bff78 ("riscv: uaccess: use 'asm_goto_output' for get_user()"), which was the first commit that started using asm goto with outputs on RISC-V, builds of clang built with assertions enabled start crashing in certain files that use get_user() with: clang: llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp:12743: Register FollowCopyChain(MachineRegisterInfo &, Register): Assertion `MI->getOpcode() == TargetOpcode::COPY && "start of copy chain MUST be COPY"' failed. Internally, LLVM generates an addiw instruction when the output of the inline asm (which may be any scalar type) needs to be sign extended for ABI reasons, such as a later function call, so that basic block does not have to do it. Use a temporary 64-bit variable as the output of the inline assembly in __get_user_asm() and explicitly cast it to truncate it if necessary, avoiding the addiw that triggers the assertion. Link: ClangBuiltLinux#2092 Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Linux RISC-V bot <linux.riscv.bot@gmail.com>
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Patch 1: "[RFC] riscv: Use 64-bit variable for output in __get_user_asm" |
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Patch 1: "[RFC] riscv: Use 64-bit variable for output in __get_user_asm" |
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Patch 1: "[RFC] riscv: Use 64-bit variable for output in __get_user_asm" |
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Patch 1: "[RFC] riscv: Use 64-bit variable for output in __get_user_asm" |
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Patch 1: "[RFC] riscv: Use 64-bit variable for output in __get_user_asm" |
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Patch 1: "[RFC] riscv: Use 64-bit variable for output in __get_user_asm" |
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Patch 1: "[RFC] riscv: Use 64-bit variable for output in __get_user_asm" |
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Patch 1: "[RFC] riscv: Use 64-bit variable for output in __get_user_asm" |
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Patch 1: "[RFC] riscv: Use 64-bit variable for output in __get_user_asm" |
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Patch 1: "[RFC] riscv: Use 64-bit variable for output in __get_user_asm" |
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Patch 1: "[RFC] riscv: Use 64-bit variable for output in __get_user_asm" |
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Patch 1: "[RFC] riscv: Use 64-bit variable for output in __get_user_asm" |
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PR for series 990331 applied to workflow__riscv__fixes
Name: [RFC] riscv: Use 64-bit variable for output in __get_user_asm
URL: https://patchwork.kernel.org/project/linux-riscv/list/?series=990331
Version: 1