Commit 307e5042 authored by Naveen N. Rao's avatar Naveen N. Rao Committed by Michael Ellerman
Browse files

powerpc/bpf: Reject atomic ops in ppc32 JIT 



Commit 91c960b0 ("bpf: Rename BPF_XADD and prepare to encode other
atomics in .imm") converted BPF_XADD to BPF_ATOMIC and updated all JIT
implementations to reject JIT'ing instructions with an immediate value
different from BPF_ADD. However, ppc32 BPF JIT was implemented around
the same time and didn't include the same change. Update the ppc32 JIT
accordingly.

Fixes: 51c66ad8 ("powerpc/bpf: Implement extended BPF on PPC32")
Cc: stable@vger.kernel.org # v5.13+
Signed-off-by: default avatarNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/426699046d89fe50f66ecf74bd31c01eda976ba5.1625145429.git.naveen.n.rao@linux.vnet.ibm.com
parent 419ac821

arch/powerpc/net/bpf_jit_comp32.c

+11 −3
Original line number Diff line number Diff line
@@ -773,9 +773,17 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context * 
			break;



		/*

		 * BPF_STX XADD (atomic_add)

		 * BPF_STX ATOMIC (atomic ops)

		 */

		case BPF_STX | BPF_XADD | BPF_W: /* *(u32 *)(dst + off) += src */

		case BPF_STX | BPF_ATOMIC | BPF_W:

			if (imm != BPF_ADD) {

				pr_err_ratelimited("eBPF filter atomic op code %02x (@%d) unsupported\n",

						   code, i);

				return -ENOTSUPP;

			}



			/* *(u32 *)(dst + off) += src */



			bpf_set_seen_register(ctx, tmp_reg);

			/* Get offset into TMP_REG */

			EMIT(PPC_RAW_LI(tmp_reg, off));
@@ -789,7 +797,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context * 
			PPC_BCC_SHORT(COND_NE, (ctx->idx - 3) * 4);

			break;



		case BPF_STX | BPF_XADD | BPF_DW: /* *(u64 *)(dst + off) += src */

		case BPF_STX | BPF_ATOMIC | BPF_DW: /* *(u64 *)(dst + off) += src */

			return -EOPNOTSUPP;



		/*