From: Yonghong Song <yonghong.song@linux.dev>
To: Eduard Zingerman <eddyz87@gmail.com>, bpf@vger.kernel.org
Cc: Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andrii@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
kernel-team@fb.com, Martin KaFai Lau <martin.lau@kernel.org>
Subject: Re: [PATCH bpf-next v2 1/2] bpf: Get better reg range with ldsx and 32bit compare
Date: Fri, 12 Jul 2024 14:30:33 -0700 [thread overview]
Message-ID: <28749f56-3058-434c-bba2-804f81f4781c@linux.dev> (raw)
In-Reply-To: <fae1d2787b5340209429c83111cb6a1b92a66308.camel@gmail.com>
On 7/12/24 1:50 PM, Eduard Zingerman wrote:
> [...]
>
> Also,
>
>> + /* Here we would like to handle a special case after sign extending load,
>> + * when upper bits for a 64-bit range are all 1s or all 0s.
>> + *
>> + * Upper bits are all 1s when register is in a rage:
> ^^^^
> I missed 'n' here, sorry
Ack. I fixed a couple of places but missed this one. Will make
a change in next revision.
>
>> + * [0xffff_ffff_0000_0000, 0xffff_ffff_ffff_ffff]
>> + * Upper bits are all 0s when register is in a range:
>> + * [0x0000_0000_0000_0000, 0x0000_0000_ffff_ffff]
>> + * Together this forms are continuous range:
>> + * [0xffff_ffff_0000_0000, 0x0000_0000_ffff_ffff]
> [...]
>
prev parent reply other threads:[~2024-07-12 21:30 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-12 20:28 [PATCH bpf-next v2 1/2] bpf: Get better reg range with ldsx and 32bit compare Yonghong Song
2024-07-12 20:28 ` [PATCH bpf-next v2 2/2] selftests/bpf: Add ldsx selftests for ldsx and subreg compare Yonghong Song
2024-07-12 20:30 ` [PATCH bpf-next v2 1/2] bpf: Get better reg range with ldsx and 32bit compare Alexei Starovoitov
2024-07-12 21:24 ` Yonghong Song
2024-07-12 20:49 ` Eduard Zingerman
2024-07-12 21:29 ` Yonghong Song
2024-07-12 20:50 ` Eduard Zingerman
2024-07-12 21:30 ` Yonghong Song [this message]
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