From: Daniel Borkmann <daniel@iogearbox•net>
To: David Miller <davem@davemloft•net>
Cc: sparclinux@vger•kernel.org, netdev@vger•kernel.org, ast@kernel•org
Subject: Re: [PATCH RFC] sparc64: eBPF JIT
Date: Mon, 17 Apr 2017 22:55:01 +0200 [thread overview]
Message-ID: <58F52BA5.1090808@iogearbox.net> (raw)
In-Reply-To: <20170417.150326.345314944044934203.davem@davemloft.net>
On 04/17/2017 09:03 PM, David Miller wrote:
> From: Daniel Borkmann <daniel@iogearbox•net>
> Date: Mon, 17 Apr 2017 20:44:35 +0200
>
>> On 04/17/2017 05:38 AM, David Miller wrote:
>>> +/* Map BPF registers to SPARC registers */
>>> +static const int bpf2sparc[] = {
>>> + /* return value from in-kernel function, and exit value from eBPF */
>>> + [BPF_REG_0] = I5,
>>> +
>>> + /* arguments from eBPF program to in-kernel function */
>>> + [BPF_REG_1] = I0,
>>> + [BPF_REG_2] = I1,
>>> + [BPF_REG_3] = I2,
>>> + [BPF_REG_4] = I3,
>>> + [BPF_REG_5] = I4,
>>> +
>>> + /* callee saved registers that in-kernel function will preserve */
>>> + [BPF_REG_6] = L0,
>>> + [BPF_REG_7] = L1,
>>> + [BPF_REG_8] = L2,
>>> + [BPF_REG_9] = L3,
>>> +
>>> + /* read-only frame pointer to access stack */
>>> + [BPF_REG_FP] = FP,
>>
>> On a quick initial glance, you also need to map BPF_REG_AX. If
>> I understand the convention correctly, you could use L7 for that.
>>
>> You can test for it through tools/testing/selftests/bpf/test_kmod.sh
>> which exercises the test_bpf.ko under various sysctl combinations as
>> part of the BPF selftest suite.
>
> Oh I see, it's used for constant blinding. I can use a global register
> for that since it's only used as a temporary right?
Yeah, correct.
next prev parent reply other threads:[~2017-04-17 20:55 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-17 3:38 [PATCH RFC] sparc64: eBPF JIT David Miller
2017-04-17 18:44 ` Daniel Borkmann
2017-04-17 19:03 ` David Miller
2017-04-17 20:55 ` Daniel Borkmann [this message]
2017-04-17 20:12 ` David Miller
2017-04-21 16:46 ` David Miller
2017-04-21 16:50 ` Daniel Borkmann
2017-04-21 18:49 ` Alexei Starovoitov
2017-04-21 19:02 ` David Miller
2017-04-21 19:26 ` Alexei Starovoitov
2017-04-21 19:41 ` David Miller
2017-04-17 23:27 ` Alexei Starovoitov
2017-04-18 1:12 ` David Miller
2017-04-18 5:44 ` Alexei Starovoitov
2017-04-18 18:37 ` David Miller
2017-04-18 22:57 ` Alexei Starovoitov
2017-04-19 2:27 ` David Miller
2017-04-22 1:19 ` David Miller
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