Support Arena on ARM64 #6622
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Support Arena on ARM64 #6622
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Add support for [LDX | STX | ST], PROBE_MEM32, [B | H | W | DW] instructions. They are similar to PROBE_MEM instructions with the following differences: - PROBE_MEM32 supports store. - PROBE_MEM32 relies on the verifier to clear upper 32-bit of the src/dst register - PROBE_MEM32 adds 64-bit kern_vm_start address (which is stored in R28 in the prologue). Due to bpf_arena constructions such R28 + reg + off16 access is guaranteed to be within arena virtual range, so no address check at run-time. - PROBE_MEM32 allows STX and ST. If they fault the store is a nop. When LDX faults the destination register is zeroed. To support these on arm64, we do tmp2 = R28 + src/dst reg and then use tmp2 as the new src/dst register. This allows us to reuse most of the code for normal [LDX | STX | ST]. Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
LLVM generates bpf_addr_space_cast instruction while translating pointers between native (zero) address space and __attribute__((address_space(N))). The addr_space=1 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) has to be converted by JIT: Here I explain using symbolic language what the JIT is supposed to do: We have: src = [src_upper32][src_lower32] // 64 bit src kernel pointer uvm = [uvm_upper32][uvm_lower32] // 64 bit user_vm_start The JIT has to make the dst reg like following dst = [uvm_upper32][src_lower32] // if src_lower32 != 0 dst = [00000000000][00000000000] // if src_lower32 == 0 Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
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The arena_list selftest uses (1ull << 32) in the mmap address computation for arm64. Use the same in the verifier_arena selftest. This makes the selftest pass for arm64 on the CI[1]. [1] kernel-patches/bpf#6622 Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
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The arena_list selftest uses (1ull << 32) in the mmap address computation for arm64. Use the same in the verifier_arena selftest. This makes the selftest pass for arm64 on the CI[1]. [1] #6622 Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
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Everything looks good, sent the patch to fix the selftest to the list. |
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The arena_list selftest uses (1ull << 32) in the mmap address computation for arm64. Use the same in the verifier_arena selftest. This makes the selftest pass for arm64 on the CI[1]. [1] #6622 Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
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The arena_list selftest uses (1ull << 32) in the mmap address computation for arm64. Use the same in the verifier_arena selftest. This makes the selftest pass for arm64 on the CI[1]. [1] kernel-patches/bpf#6622 Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
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The arena_list selftest uses (1ull << 32) in the mmap address computation for arm64. Use the same in the verifier_arena selftest. This makes the selftest pass for arm64 on the CI[1]. [1] kernel-patches/bpf#6622 Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
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The arena_list selftest uses (1ull << 32) in the mmap address computation for arm64. Use the same in the verifier_arena selftest. This makes the selftest pass for arm64 on the CI[1]. [1] #6622 Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
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The arena_list selftest uses (1ull << 32) in the mmap address computation for arm64. Use the same in the verifier_arena selftest. This makes the selftest pass for arm64 on the CI[1]. [1] kernel-patches/bpf#6622 Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
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The arena_list selftest uses (1ull << 32) in the mmap address computation for arm64. Use the same in the verifier_arena selftest. This makes the selftest pass for arm64 on the CI[1]. [1] #6622 Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
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The arena_list selftest uses (1ull << 32) in the mmap address computation for arm64. Use the same in the verifier_arena selftest. This makes the selftest pass for arm64 on the CI[1]. [1] #6622 Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
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The arena_list selftest uses (1ull << 32) in the mmap address computation for arm64. Use the same in the verifier_arena selftest. This makes the selftest pass for arm64 on the CI[1]. [1] kernel-patches/bpf#6622 Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
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The arena_list selftest uses (1ull << 32) in the mmap address computation for arm64. Use the same in the verifier_arena selftest. This makes the selftest pass for arm64 on the CI[1]. [1] kernel-patches/bpf#6622 Signed-off-by: Puranjay Mohan <puranjay12@gmail.com> Link: https://lore.kernel.org/r/20240322133552.70681-1-puranjay12@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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The arena_list selftest uses (1ull << 32) in the mmap address computation for arm64. Use the same in the verifier_arena selftest. This makes the selftest pass for arm64 on the CI[1]. [1] kernel-patches#6622 Signed-off-by: Puranjay Mohan <puranjay12@gmail.com> Link: https://lore.kernel.org/r/20240322133552.70681-1-puranjay12@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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The arena_list selftest uses (1ull << 32) in the mmap address computation for arm64. Use the same in the verifier_arena selftest. This makes the selftest pass for arm64 on the CI[1]. [1] kernel-patches/bpf#6622 Signed-off-by: Puranjay Mohan <puranjay12@gmail.com> Link: https://lore.kernel.org/r/20240322133552.70681-1-puranjay12@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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The arena_list selftest uses (1ull << 32) in the mmap address computation for arm64. Use the same in the verifier_arena selftest. This makes the selftest pass for arm64 on the CI[1]. [1] kernel-patches/bpf#6622 Signed-off-by: Puranjay Mohan <puranjay12@gmail.com> Link: https://lore.kernel.org/r/20240322133552.70681-1-puranjay12@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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The selftest is failing on the CI but passing on my local setup. A change in the selftest might fix it.