[PATCH 2/2] arm64: bpf: add extra pass to handle faulty codegen
davem at davemloft.net
Sun Jan 17 16:15:45 PST 2016
From: Zi Shen Lim <zlim.lnx at gmail.com>
Date: Wed, 13 Jan 2016 23:33:22 -0800
> Code generation functions in arch/arm64/kernel/insn.c previously
> BUG_ON invalid parameters. Following change of that behavior, now we
> need to handle the error case where AARCH64_BREAK_FAULT is returned.
> Instead of error-handling on every emit() in JIT, we add a new
> validation pass at the end of JIT compilation. There's no point in
> running JITed code at run-time only to trap due to AARCH64_BREAK_FAULT.
> Instead, we drop this failed JIT compilation and allow the system to
> gracefully fallback on the BPF interpreter.
> Signed-off-by: Zi Shen Lim <zlim.lnx at gmail.com>
> Suggested-by: Alexei Starovoitov <ast at kernel.org>
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