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0c1da35b01
powerpc supports BPF atomic operations using a loop around Load-And-Reserve(LDARX/LWARX) and Store-Conditional(STDCX/STWCX) instructions gated by sync instructions to enforce full ordering. To implement arena_atomics, arena vm start address is added to the dst_reg to be used for both the LDARX/LWARX and STDCX/STWCX instructions. Further, an exception table entry is added for LDARX/LWARX instruction to land after the loop on fault. At the end of sequence, dst_reg is restored by subtracting arena vm start address. bpf_jit_supports_insn() is introduced to selectively enable instruction support as in other architectures like x86 and arm64. Reviewed-by: Hari Bathini <hbathini@linux.ibm.com> Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com> Signed-off-by: Saket Kumar Bhaskar <skb99@linux.ibm.com> Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com> Link: https://patch.msgid.link/20250904100835.1100423-5-skb99@linux.ibm.com