From: Daniel Borkmann <daniel@iogearbox.net>
Date: Thu, 10 Oct 2019 23:49:16 +0000 (+0200)
Subject: Merge branch 'bpf-romap-known-scalars'
X-Git-Tag: for-linus-20191129~13^2~365^2~9
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=63098555cfe09a633b74a3c9963769c6d4df8432;p=linux-2.6-block.git

Merge branch 'bpf-romap-known-scalars'

Andrii Nakryiko says:

====================
With BPF maps supporting direct map access (currently, array_map w/ single
element, used for global data) that are read-only both from system call and
BPF side, it's possible for BPF verifier to track its contents as known
constants.

Now it's possible for user-space control app to pre-initialize read-only map
(e.g., for .rodata section) with user-provided flags and parameters and rely
on BPF verifier to detect and eliminate dead code resulting from specific
combination of input parameters.

v1->v2:
- BPF_F_RDONLY means nothing, stick to just map->frozen (Daniel);
- stick to passing just offset into map_direct_value_addr (Martin).
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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63098555cfe09a633b74a3c9963769c6d4df8432