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ftrace,bpf: Use single direct ops for bpf trampolines #10558

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@kernel-patches-daemon-bpf kernel-patches-daemon-bpf bot commented Dec 30, 2025

Pull request for series with
subject: ftrace,bpf: Use single direct ops for bpf trampolines
version: 1
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=1037389

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kernel-patches-daemon-bpf bot commented Dec 30, 2025

Upstream branch: f14cdb1
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1037389
version: 1

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Upstream branch: f14cdb1
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1037389
version: 1

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Upstream branch: 6006058
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1037389
version: 1

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Upstream branch: 317a5df
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1037389
version: 1

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Upstream branch: ccaa6d2
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1037389
version: 1

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Upstream branch: ccaa6d2
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1037389
version: 1

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Upstream branch: ccaa6d2
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1037389
version: 1

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Upstream branch: 1a8fa7f
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1037389
version: 1

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Upstream branch: a069190
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1037389
version: 1

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Upstream branch: a069190
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1037389
version: 1

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Upstream branch: ea180ff
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1037389
version: 1

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kernel-patches-daemon-bpf bot commented Jan 7, 2026

Upstream branch: a8d5067
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1037389
version: 1

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kernel-patches-daemon-bpf bot commented Jan 7, 2026

Upstream branch: 2421649
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1037389
version: 1

@olsajiri
ftrace,bpf: Remove FTRACE_OPS_FL_JMP ftrace_ops flag
eddec32 
At the moment the we allow the jmp attach only for ftrace_ops that
has FTRACE_OPS_FL_JMP set. This conflicts with following changes
where we use single ftrace_ops object for all direct call sites,
so all could be be attached via just call or jmp.

We already limit the jmp attach support with config option and bit
(LSB) set on the trampoline address. It turns out that's actually
enough to limit the jmp attach for architecture and only for chosen
addresses (with LSB bit set).

Each user of register_ftrace_direct or modify_ftrace_direct can set
the trampoline bit (LSB) to indicate it has to be attached by jmp.

The bpf trampoline generation code uses trampoline flags to generate
jmp-attach specific code and ftrace inner code uses the trampoline
bit (LSB) to handle return from jmp attachment, so there's no harm
to remove the FTRACE_OPS_FL_JMP bit.

The fexit/fmodret performance stays the same (did not drop),
current code:

  fentry         :   77.904 ± 0.546M/s
  fexit          :   62.430 ± 0.554M/s
  fmodret        :   66.503 ± 0.902M/s

with this change:

  fentry         :   80.472 ± 0.061M/s
  fexit          :   63.995 ± 0.127M/s
  fmodret        :   67.362 ± 0.175M/s

Fixes: 25e4e35 ("ftrace: Introduce FTRACE_OPS_FL_JMP")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
@olsajiri
ftrace: Make alloc_and_copy_ftrace_hash direct friendly
73dcfbc 
Make alloc_and_copy_ftrace_hash to copy also direct address
for each hash entry.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
@olsajiri
ftrace: Export some of hash related functions
7488632 
We are going to use these functions in following changes.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
@olsajiri
ftrace: Add update_ftrace_direct_add function
d692ae5 
Adding update_ftrace_direct_add function that adds all entries
(ip -> addr) provided in hash argument to direct ftrace ops
and updates its attachments.

The difference to current register_ftrace_direct is
 - hash argument that allows to register multiple ip -> direct
   entries at once
 - we can call update_ftrace_direct_add multiple times on the
   same ftrace_ops object, becase after first registration with
   register_ftrace_function_nolock, it uses ftrace_update_ops to
   update the ftrace_ops object

This change will allow us to have simple ftrace_ops for all bpf
direct interface users in following changes.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
@olsajiri
ftrace: Add update_ftrace_direct_del function
39057e7 
Adding update_ftrace_direct_del function that removes all entries
(ip -> addr) provided in hash argument to direct ftrace ops and
updates its attachments.

The difference to current unregister_ftrace_direct is
 - hash argument that allows to unregister multiple ip -> direct
   entries at once
 - we can call update_ftrace_direct_del multiple times on the
   same ftrace_ops object, becase we do not need to unregister
   all entries at once, we can do it gradualy with the help of
   ftrace_update_ops function

This change will allow us to have simple ftrace_ops for all bpf
direct interface users in following changes.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
@olsajiri
ftrace: Add update_ftrace_direct_mod function
3334031 
Adding update_ftrace_direct_mod function that modifies all entries
(ip -> direct) provided in hash argument to direct ftrace ops and
updates its attachments.

The difference to current modify_ftrace_direct is:
- hash argument that allows to modify multiple ip -> direct
  entries at once

This change will allow us to have simple ftrace_ops for all bpf
direct interface users in following changes.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
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kernel-patches-daemon-bpf bot commented Jan 7, 2026

Upstream branch: 2175ccf
series: https://patchwork.kernel.org/project/netdevbpf/list/?series=1037389
version: 1

@olsajiri
bpf: Add trampoline ip hash table
0ff6641 
Following changes need to lookup trampoline based on its ip address,
adding hash table for that.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
@olsajiri
ftrace: Factor ftrace_ops ops_func interface
80b9002 
We are going to remove "ftrace_ops->private == bpf_trampoline" setup
in following changes.

Adding ip argument to ftrace_ops_func_t callback function, so we can
use it to look up the trampoline.

Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
@olsajiri
bpf,x86: Use single ftrace_ops for direct calls
e9cbe74 
Using single ftrace_ops for direct calls update instead of allocating
ftrace_ops object for each trampoline.

With single ftrace_ops object we can use update_ftrace_direct_* api
that allows multiple ip sites updates on single ftrace_ops object.

Adding HAVE_SINGLE_FTRACE_DIRECT_OPS config option to be enabled on
each arch that supports this.

At the moment we can enable this only on x86 arch, because arm relies
on ftrace_ops object representing just single trampoline image (stored
in ftrace_ops::direct_call). Archs that do not support this will continue
to use *_ftrace_direct api.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
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