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bpf: Add bitwise atomic instructions
This adds instructions for atomic[64]_[fetch_]and atomic[64]_[fetch_]or atomic[64]_[fetch_]xor All these operations are isomorphic enough to implement with the same verifier, interpreter, and x86 JIT code, hence being a single commit. The main interesting thing here is that x86 doesn't directly support the fetch_ version these operations, so we need to generate a CMPXCHG loop in the JIT. This requires the use of two temporary registers, IIUC it's safe to use BPF_REG_AX and x86's AUX_REG for this purpose. Signed-off-by:Brendan Jackman <jackmanb@google.com> Signed-off-by:
Alexei Starovoitov <ast@kernel.org> Acked-by:
Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20210114181751.768687-10-jackmanb@google.com
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- arch/x86/net/bpf_jit_comp.c 49 additions, 1 deletionarch/x86/net/bpf_jit_comp.c
- include/linux/filter.h 6 additions, 0 deletionsinclude/linux/filter.h
- kernel/bpf/core.c 3 additions, 0 deletionskernel/bpf/core.c
- kernel/bpf/disasm.c 17 additions, 4 deletionskernel/bpf/disasm.c
- kernel/bpf/verifier.c 6 additions, 0 deletionskernel/bpf/verifier.c
- tools/include/linux/filter.h 6 additions, 0 deletionstools/include/linux/filter.h
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