Messages in this thread | | | Date | Mon, 12 Jun 2017 12:06:11 +0100 | From | Russell King - ARM Linux <> | Subject | Re: [PATCH v2] arm: eBPF JIT compiler |
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On Mon, Jun 12, 2017 at 12:21:03PM +0200, Daniel Borkmann wrote: > On 05/30/2017 09:19 PM, Kees Cook wrote: > >On Thu, May 25, 2017 at 4:13 PM, Shubham Bansal > ><illusionist.neo@gmail.com> wrote: > >>+static int validate_code(struct jit_ctx *ctx) > >>+{ > >>+ int i; > >>+ > >>+ for (i = 0; i < ctx->idx; i++) { > >>+ u32 a32_insn = le32_to_cpu(ctx->target[i]); > > Given __opcode_to_mem_arm(ARM_INST_UDF) is used to fill the image, > perhaps use the __mem_to_opcode_arm() helper for the check? > > >>+ if (a32_insn == ARM_INST_UDF)
The following is probably better:
if (ctx->target[i] == __opcode_to_mem_arm(ARM_INST_UDF))
since then you can take advantage of the compiler optimising the constant rather than having to do a byte swap on an unknown 32-bit value.
-- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net.
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