bpf: Add arm64 JIT support for bpf_addr_space_cast instruction.

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LLVM generates bpf_addr_space_cast instruction while translating
pointers between native (zero) address space and
__attribute__((address_space(N))). The addr_space=0 is reserved as
bpf_arena address space.

rY = addr_space_cast(rX, 0, 1) is processed by the verifier and
converted to normal 32-bit move: wX = wY.

rY = addr_space_cast(rX, 1, 0) : used to convert a bpf arena pointer to
a pointer in the userspace vma. This has to be converted by the JIT.

Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
Link: https://lore.kernel.org/r/20240325150716.4387-3-puranjay12@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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Puranjay Mohan 2024-03-25 15:07:16 +00:00 • committed by Alexei Starovoitov

parent 339af577ec

commit 4dd31243e3

2 changed files with 16 additions and 2 deletions

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16

arch/arm64/net/bpf_jit_comp.c

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2

tools/testing/selftests/bpf/DENYLIST.aarch64

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