From: Jiong Wang <jiong.wang@netronome.com>
To: Jann Horn <jannh@google.com>
Cc: Jiong Wang <jiong.wang@netronome.com>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Daniel Borkmann <daniel@iogearbox.net>,
bpf@vger.kernel.org, Network Development <netdev@vger.kernel.org>,
oss-drivers@netronome.com
Subject: Re: [PATCH/RFC bpf-next 03/16] bpf: split read liveness into REG_LIVE_READ64 and REG_LIVE_READ32
Date: Tue, 26 Mar 2019 20:50:58 +0000 [thread overview]
Message-ID: <87lg114ax9.fsf@netronome.com> (raw)
In-Reply-To: <CAG48ez0inUUF3wZw5P6o35T3CKQ=CEue1vo-H-dSLDKKo2OHow@mail.gmail.com>
Jann Horn writes:
> On Tue, Mar 26, 2019 at 7:06 PM Jiong Wang <jiong.wang@netronome.com> wrote:
>>
>> In previous patch, we have split register arg type for sub-register read,
>> but haven't touch read liveness.
>>
>> This patch further split read liveness into REG_LIVE_READ64 and
>> REG_LIVE_READ32. Liveness propagation code are updated accordingly.
>>
>> After this split, customized actions could be defined when propagating full
>> register read (REG_LIVE_READ64) or sub-register read (REG_LIVE_READ32).
>>
>> Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
> [...]
>> @@ -1374,7 +1374,8 @@ static int check_stack_read(struct bpf_verifier_env *env,
>> return -EACCES;
>> }
>> mark_reg_read(env, ®_state->stack[spi].spilled_ptr,
>> - reg_state->stack[spi].spilled_ptr.parent);
>> + reg_state->stack[spi].spilled_ptr.parent,
>> + size == BPF_REG_SIZE);
>
> Isn't it possible to use a 4-byte read on the upper half of an 8-byte
> stack slot?
I think that's fine, and is irrelevant with zero-extension on register.
If it is a 8-byte stack slot comes from spill of register, then the
definition of the register should have been marked as needing
zero-extension if that register was generated by sub-register write.
Regards,
Jiong
>
>> if (value_regno >= 0) {
>> if (zeros == size) {
>> /* any size read into register is zero extended,
>> @@ -2220,7 +2221,8 @@ static int check_stack_boundary(struct bpf_verifier_env *env, int regno,
>> * the whole slot to be marked as 'read'
>> */
>> mark_reg_read(env, &state->stack[spi].spilled_ptr,
>> - state->stack[spi].spilled_ptr.parent);
>> + state->stack[spi].spilled_ptr.parent,
>> + access_size == BPF_REG_SIZE);
>
> Same thing as above.
>
>> }
>> return update_stack_depth(env, state, off);
>> }
> [...]
next prev parent reply other threads:[~2019-03-26 20:51 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-26 18:05 [PATCH/RFC bpf-next 00/16] bpf: eliminate zero extensions for sub-register writes Jiong Wang
2019-03-26 18:05 ` [PATCH/RFC bpf-next 01/16] bpf: turn "enum bpf_reg_liveness" into bit representation Jiong Wang
2019-03-27 15:44 ` Alexei Starovoitov
2019-03-26 18:05 ` [PATCH/RFC bpf-next 02/16] bpf: refactor propagate_live implementation Jiong Wang
2019-03-26 18:26 ` Jann Horn
2019-03-26 19:45 ` Jiong Wang
2019-03-27 16:35 ` Alexei Starovoitov
2019-03-27 16:44 ` Jiong Wang
2019-03-26 18:05 ` [PATCH/RFC bpf-next 03/16] bpf: split read liveness into REG_LIVE_READ64 and REG_LIVE_READ32 Jiong Wang
2019-03-26 20:21 ` Jann Horn
2019-03-26 20:50 ` Jiong Wang [this message]
2019-03-27 16:38 ` Alexei Starovoitov
2019-03-26 18:05 ` [PATCH/RFC bpf-next 04/16] bpf: mark sub-register writes that really need zero extension to high bits Jiong Wang
2019-03-26 18:44 ` Edward Cree
2019-03-26 19:47 ` Jiong Wang
2019-04-05 20:44 ` Jiong Wang
2019-04-06 3:41 ` Alexei Starovoitov
2019-04-06 6:56 ` Jiong Wang
2019-04-07 2:51 ` Alexei Starovoitov
2019-03-27 16:50 ` Alexei Starovoitov
2019-03-27 17:06 ` Jiong Wang
2019-03-26 18:05 ` [PATCH/RFC bpf-next 05/16] bpf: reduce false alarm by refining "enum bpf_arg_type" Jiong Wang
2019-03-26 18:05 ` [PATCH/RFC bpf-next 06/16] bpf: new sysctl "bpf_jit_32bit_opt" Jiong Wang
2019-03-27 17:00 ` Alexei Starovoitov
2019-03-27 17:06 ` Jiong Wang
2019-03-27 17:17 ` Alexei Starovoitov
2019-03-27 17:18 ` Jiong Wang
2019-03-27 17:45 ` Alexei Starovoitov
2019-03-27 19:13 ` Jiong Wang
2019-03-26 18:05 ` [PATCH/RFC bpf-next 07/16] bpf: insert explicit zero extension instructions when bpf_jit_32bit_opt is true Jiong Wang
2019-03-26 18:05 ` [PATCH/RFC bpf-next 08/16] arm: bpf: eliminate zero extension code-gen Jiong Wang
2019-03-26 18:05 ` [PATCH/RFC bpf-next 09/16] powerpc: " Jiong Wang
2019-03-26 18:05 ` [PATCH/RFC bpf-next 10/16] s390: " Jiong Wang
2019-03-26 18:05 ` [PATCH/RFC bpf-next 11/16] sparc: " Jiong Wang
2019-03-26 18:05 ` [PATCH/RFC bpf-next 12/16] x32: " Jiong Wang
2019-03-26 18:05 ` [PATCH/RFC bpf-next 13/16] riscv: " Jiong Wang
2019-03-26 18:05 ` [PATCH/RFC bpf-next 14/16] nfp: " Jiong Wang
2019-03-26 18:05 ` [PATCH/RFC bpf-next 15/16] selftests: bpf: new field "xlated_insns" for insn scan test after verification Jiong Wang
2019-03-26 18:05 ` [PATCH/RFC bpf-next 16/16] selftests: bpf: unit testcases for zero extension insertion pass Jiong Wang
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87lg114ax9.fsf@netronome.com \
--to=jiong.wang@netronome.com \
--cc=alexei.starovoitov@gmail.com \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=jannh@google.com \
--cc=netdev@vger.kernel.org \
--cc=oss-drivers@netronome.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).