bpf, x86: Make sure allocation in arch_bpf_trampoline_size() is writable

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arch_bpf_trampoline_size() allocates a buffer to get actual size required
for a trampoline.

This buffer must be in the module address space because
__arch_prepare_bpf_trampoline() calculates  rel32 offsets relatively to
that buffer.

In preparation for enabling ROX mode for EXECMEM_BPF make sure that the
allocated memory is writable.

Add bpf_jit_alloc_exec_rw() wrapper for execmem_alloc_rw() and use it for
buffer allocation in arch_bpf_trampoline_size().

Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/bpf/20260716-execmem-x86-rox-bpf-v0-v3-4-4e76158c01c5@kernel.org
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

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Mike Rapoport (Microsoft) 2026-07-16 10:51:38 +03:00 • committed by Kumar Kartikeya Dwivedi

parent 7516714947

commit 5bf02dbf39

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3 changed files with 8 additions and 3 deletions

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5

arch/x86/net/bpf_jit_comp.c

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1

include/linux/filter.h

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5

kernel/bpf/core.c

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