[SRU][J:linux][PATCH v2 2/4] powerpc/bpf/64: add support for BPF_ATOMIC bitwise operations

[Andrei Gherzan]

BugLink: https://bugs.launchpad.net/bugs/1955011

Adding instructions for ppc64 for

atomic[64]_and
atomic[64]_or
atomic[64]_xor

Signed-off-by: Hari Bathini <hbathini at linux.ibm.com>
Tested-by: Naveen N. Rao <naveen.n.rao at linux.vnet.ibm.com> (ppc64le)
Reviewed-by: Naveen N. Rao <naveen.n.rao at linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
Link: https://lore.kernel.org/r/20220610155552.25892-2-hbathini@linux.ibm.com
(backported from commit 65112709115f48f16d7082bcabf173d08622e69f)
[agherzan: Context adjustment - used b2p[TMP_REG_x] notation consistent
 with existing Ubuntu Jammy code instead of upstream's tmp1_reg/tmp2_reg
 local variables. Used BPF_SIZE(code) inline instead of separate size
 variable.]
Signed-off-by: Andrei Gherzan <andrei.gherzan at canonical.com>
---
 arch/powerpc/net/bpf_jit_comp64.c | 57 ++++++++++++++++---------------
 1 file changed, 29 insertions(+), 28 deletions(-)

diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
index 6f4a7bcf53aa..b3729f511ac0 100644
--- a/arch/powerpc/net/bpf_jit_comp64.c
+++ b/arch/powerpc/net/bpf_jit_comp64.c
@@ -742,41 +742,42 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
 		 * BPF_STX ATOMIC (atomic ops)
 		 */
 		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 */
-
-			/* Get EA into TMP_REG_1 */
-			EMIT(PPC_RAW_ADDI(b2p[TMP_REG_1], dst_reg, off));
+		case BPF_STX | BPF_ATOMIC | BPF_DW:
+			/* Get offset into TMP_REG_1 */
+			EMIT(PPC_RAW_LI(b2p[TMP_REG_1], off));
 			tmp_idx = ctx->idx * 4;
 			/* load value from memory into TMP_REG_2 */
-			EMIT(PPC_RAW_LWARX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1], 0));
-			/* add value from src_reg into this */
-			EMIT(PPC_RAW_ADD(b2p[TMP_REG_2], b2p[TMP_REG_2], src_reg));
-			/* store result back */
-			EMIT(PPC_RAW_STWCX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1]));
-			/* we're done if this succeeded */
-			PPC_BCC_SHORT(COND_NE, tmp_idx);
-			break;
-		case BPF_STX | BPF_ATOMIC | BPF_DW:
-			if (imm != BPF_ADD) {
+			if (BPF_SIZE(code) == BPF_DW)
+				EMIT(PPC_RAW_LDARX(b2p[TMP_REG_2], b2p[TMP_REG_1], dst_reg, 0));
+			else
+				EMIT(PPC_RAW_LWARX(b2p[TMP_REG_2], b2p[TMP_REG_1], dst_reg, 0));
+
+			switch (imm) {
+			case BPF_ADD:
+				EMIT(PPC_RAW_ADD(b2p[TMP_REG_2], b2p[TMP_REG_2], src_reg));
+				break;
+			case BPF_AND:
+				EMIT(PPC_RAW_AND(b2p[TMP_REG_2], b2p[TMP_REG_2], src_reg));
+				break;
+			case BPF_OR:
+				EMIT(PPC_RAW_OR(b2p[TMP_REG_2], b2p[TMP_REG_2], src_reg));
+				break;
+			case BPF_XOR:
+				EMIT(PPC_RAW_XOR(b2p[TMP_REG_2], b2p[TMP_REG_2], src_reg));
+				break;
+			default:
 				pr_err_ratelimited(
 					"eBPF filter atomic op code %02x (@%d) unsupported\n",
 					code, i);
-				return -ENOTSUPP;
+				return -EOPNOTSUPP;
 			}
-			/* *(u64 *)(dst + off) += src */
 
-			EMIT(PPC_RAW_ADDI(b2p[TMP_REG_1], dst_reg, off));
-			tmp_idx = ctx->idx * 4;
-			EMIT(PPC_RAW_LDARX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1], 0));
-			EMIT(PPC_RAW_ADD(b2p[TMP_REG_2], b2p[TMP_REG_2], src_reg));
-			EMIT(PPC_RAW_STDCX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1]));
+			/* store result back */
+			if (BPF_SIZE(code) == BPF_DW)
+				EMIT(PPC_RAW_STDCX(b2p[TMP_REG_2], b2p[TMP_REG_1], dst_reg));
+			else
+				EMIT(PPC_RAW_STWCX(b2p[TMP_REG_2], b2p[TMP_REG_1], dst_reg));
+			/* we're done if this succeeded */
 			PPC_BCC_SHORT(COND_NE, tmp_idx);
 			break;
 
-- 
2.43.0