perf tools: Fix prologue generation #3109
Closed
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
|
Master branch: f175ece |
|
Master branch: f913ad6 |
kernel-patches-bot
force-pushed
the
series/634594=>bpf-next
branch
from
d91190c
to
8319448
Compare
|
Master branch: f913ad6 |
kernel-patches-bot
force-pushed
the
series/634594=>bpf-next
branch
from
8319448
to
eac041c
Compare
|
Master branch: 4349680 |
kernel-patches-bot
force-pushed
the
series/634594=>bpf-next
branch
from
eac041c
to
f92cce1
Compare
kernel-patches-bot
force-pushed
the
bpf-next
branch
from
4349680
to
02f4afe
Compare
|
Master branch: 02f4afe |
kernel-patches-bot
force-pushed
the
series/634594=>bpf-next
branch
from
f92cce1
to
d7cf874
Compare
|
Master branch: d352bd8 |
kernel-patches-bot
force-pushed
the
series/634594=>bpf-next
branch
from
d7cf874
to
e67cfda
Compare
|
Master branch: d352bd8 |
kernel-patches-bot
force-pushed
the
series/634594=>bpf-next
branch
from
e67cfda
to
0242ff0
Compare
|
Master branch: 0b81705 |
kernel-patches-bot
force-pushed
the
series/634594=>bpf-next
branch
from
0242ff0
to
cf98e41
Compare
|
Master branch: fe92833 |
Perf is using section name to declare special kprobe arguments,
which no longer works with current libbpf, that either requires
certain form of the section name or allows to register custom
handler.
Adding perf support to register 'fallback' section handler to take
care of perf kprobe programs. The fallback means that it handles
any section definition besides the ones that libbpf handles.
The handler serves two purposes:
- allows perf programs to have special arguments in section name
- allows perf to use pre-load callback where we can attach init
code (zeroing all argument registers) to each perf program
The second is essential part of new prologue generation code,
that's coming in following patch.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Some functions we use for bpf prologue generation are going to be deprecated. This change reworks current code not to use them. We need to replace following functions/struct: bpf_program__set_prep bpf_program__nth_fd struct bpf_prog_prep_result Currently we use bpf_program__set_prep to hook perf callback before program is loaded and provide new instructions with the prologue. We replace this function/ality by taking instructions for specific program, attaching prologue to them and load such new ebpf programs with prologue using separate bpf_prog_load calls (outside libbpf load machinery). Before we can take and use program instructions, we need libbpf to actually load it. This way we get the final shape of its instructions with all relocations and verifier adjustments). There's one glitch though.. perf kprobe program already assumes generated prologue code with proper values in argument registers, so loading such program directly will fail in the verifier. That's where the fallback pre-load handler fits in and prepends the initialization code to the program. Once such program is loaded we take its instructions, cut off the initialization code and prepend the prologue. I know.. sorry ;-) Suggested-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
kernel-patches-bot
force-pushed
the
series/634594=>bpf-next
branch
from
cf98e41
to
9c2cea8
Compare
|
At least one diff in series https://patchwork.kernel.org/project/netdevbpf/list/?series=647321 expired. Closing PR. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Pull request for series with
subject: perf tools: Fix prologue generation
version: 1
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=647121