[v2] bpf, x86: enable EXECMEM_ROX_CACHE for BPF allocations

[PATCH bpf-next v2 0/5] bpf, x86: enable EXECMEM_ROX_CACHE for BPF allocations

Mike Rapoport (Microsoft) posted 5 patches 2 weeks ago

Diff against v1 v3
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There is a newer version of this series

arch/x86/mm/init.c          |  4 ++--
arch/x86/net/bpf_jit_comp.c |  5 ++---
include/linux/filter.h      |  1 +
kernel/bpf/core.c           | 30 +++++++++++++++++++++---------
kernel/bpf/dispatcher.c     |  5 ++++-
5 files changed, 30 insertions(+), 15 deletions(-)

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[PATCH bpf-next v2 0/5] bpf, x86: enable EXECMEM_ROX_CACHE for BPF allocations

Posted by Mike Rapoport (Microsoft) 2 weeks ago

Hi,

BPF allocations of executable memory on x86 are essentially read-only. Most
paths that call bpf_jit_alloc_exec() immediately make it ROX with
set_memory_rox().

The code generation, at least on x86, uses separately allocated writable
buffers and then updates the actual text memory with text_poke().

These patches do several small adjustments to how BPF allocates executable
memory and enable EXECMEM_ROX_CACHE for BPF allocations on x86.

---
v2 changes:
* rebased on the current bpf-next

v1: https://patch.msgid.link/20260626-execmem-x86-rox-bpf-v0-v1-0-45a0b0ed4fe9@kernel.org

---
Mike Rapoport (Microsoft) (5):
      bpf: dispatcher: allocate bpf_dispatcher->rw_image with vmalloc()
      bpf: drop __weak from bpf_jit_alloc_exec() and bpf_jit_free_exec()
      bpf: alloc_prog_pack(): skip ROX management for already ROX memory
      bpf, x86: make sure allocation in arch_bpf_trampoline_size() is writable
      x86/bpf: enable EXECMEM_ROX_CACHE for BPF allocations

 arch/x86/mm/init.c          |  4 ++--
 arch/x86/net/bpf_jit_comp.c |  5 ++---
 include/linux/filter.h      |  1 +
 kernel/bpf/core.c           | 30 +++++++++++++++++++++---------
 kernel/bpf/dispatcher.c     |  5 ++++-
 5 files changed, 30 insertions(+), 15 deletions(-)
---
base-commit: 520d7d7942025a58a0c79a61b905a556cf3cb524
change-id: 20260626-execmem-x86-rox-bpf-v0-b4241ade80df

--
Sincerely yours,
Mike.