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| author | Puranjay Mohan <puranjay12@gmail.com> | 2024-03-25 18:07:16 +0300 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2024-04-03 05:45:50 +0300 |
| commit | 4dd31243e30843d5f63bccfb0369146e4de1a130 (patch) | |
| tree | a4016b11eba0c4d9f47f5ad4e3a0c327a50d0b66 /arch/arm64/net | |
| parent | 339af577ec05c8fc0b96f23579614ae853d913ab (diff) | |
| download | linux-4dd31243e30843d5f63bccfb0369146e4de1a130.tar.xz | |
bpf: Add arm64 JIT support for bpf_addr_space_cast instruction.
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>
Diffstat (limited to 'arch/arm64/net')
| -rw-r--r-- | arch/arm64/net/bpf_jit_comp.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index c6210b150b6a..76b91f36c729 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -82,6 +82,7 @@ struct jit_ctx { __le32 *ro_image; u32 stack_size; int fpb_offset; + u64 user_vm_start; }; struct bpf_plt { @@ -868,6 +869,15 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, /* dst = src */ case BPF_ALU | BPF_MOV | BPF_X: case BPF_ALU64 | BPF_MOV | BPF_X: + if (insn_is_cast_user(insn)) { + emit(A64_MOV(0, tmp, src), ctx); // 32-bit mov clears the upper 32 bits + emit_a64_mov_i(0, dst, ctx->user_vm_start >> 32, ctx); + emit(A64_LSL(1, dst, dst, 32), ctx); + emit(A64_CBZ(1, tmp, 2), ctx); + emit(A64_ORR(1, tmp, dst, tmp), ctx); + emit(A64_MOV(1, dst, tmp), ctx); + break; + } switch (insn->off) { case 0: emit(A64_MOV(is64, dst, src), ctx); @@ -1690,6 +1700,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) } ctx.fpb_offset = find_fpb_offset(prog); + ctx.user_vm_start = bpf_arena_get_user_vm_start(prog->aux->arena); /* * 1. Initial fake pass to compute ctx->idx and ctx->offset. @@ -2511,6 +2522,11 @@ bool bpf_jit_supports_exceptions(void) return true; } +bool bpf_jit_supports_arena(void) +{ + return true; +} + void bpf_jit_free(struct bpf_prog *prog) { if (prog->jited) { |