Messages in this thread | | | Date | Thu, 05 Dec 2019 15:45:27 +0300 | From | Alexander Lobakin <> | Subject | MIPS eBPF JIT support on pre-32R2 |
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Hey all,
I'm writing about lines arch/mips/net/ebpf_jit.c:1806-1807:
if (!prog->jit_requested || MIPS_ISA_REV < 2) return prog;
Do pre-32R2 architectures (32R1, maybe even R3000-like) actually support this eBPF JIT code? If they do, then the condition 'MIPS_ISA_REV < 2' should be removed as it is always true for them and tells CC to remove JIT completely.
If they don't support instructions from this JIT, then the line arch/mips/Kconfig:50:
select HAVE_EBPF_JIT if (!CPU_MICROMIPS)
should be changed to something like:
select HAVE_EBPF_JIT if !CPU_MICROMIPS && TARGET_ISA_REV >= 2
(and then the mentioned 'if' condition would become redundant)
At the moment it is possible to build a kernel without both JIT and interpreter, but with CONFIG_BPF_SYSCALL=y (what should not be allowed I suppose?) within the following configuration:
- select any pre-32R2 CPU (e.g. CONFIG_CPU_MIPS32_R1); - enable CONFIG_BPF_JIT (CONFIG_MIPS_EBPF_JIT will be autoselected); - enable CONFIG_BPF_JIT_ALWAYS_ON (this removes BPF interpreter from the system).
I may prepare a proper patch by myself if needed (after clarification). Thanks.
Regards, ᚷ ᛖ ᚢ ᚦ ᚠ ᚱ
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