On 08/13/2014 09:57 AM, Alexei Starovoitov wrote:
add BPF_LD_IMM64 instruction to load 64-bit immediate value into register. All previous instructions were 8-byte. This is first 16-byte instruction. Two consecutive 'struct bpf_insn' blocks are interpreted as single instruction: insn[0/1].code = BPF_LD | BPF_DW | BPF_IMM insn[0/1].dst_reg = destination register insn[0].imm = lower 32-bit insn[1].imm = upper 32-bit Classic BPF has similar instruction: BPF_LD | BPF_W | BPF_IMM which loads 32-bit immediate value into a register. x64 JITs it as single 'movabsq %rax, imm64' arm64 may JIT as sequence of four 'movk x0, #imm16, lsl #shift' insn Note that old eBPF programs are binary compatible with new interpreter. Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxxxx>
For follow-ups on this series, can you put the actual motivation for this change from the cover letter into this commit log as it otherwise doesn't say anything clearly why it is needed. Code and test case looks good to me. -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html