[PATCH 2/5] bpf ppc64: add support for atomic fetch operations

[Hari Bathini]

Adding instructions for ppc64 for

atomic[64]_fetch_add
atomic[64]_fetch_and
atomic[64]_fetch_or
atomic[64]_fetch_xor

Signed-off-by: Hari Bathini <hbath...@linux.ibm.com>
---
 arch/powerpc/net/bpf_jit_comp64.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/net/bpf_jit_comp64.c 
b/arch/powerpc/net/bpf_jit_comp64.c
index b34ed88167f0..504fa459f9f3 100644
--- a/arch/powerpc/net/bpf_jit_comp64.c
+++ b/arch/powerpc/net/bpf_jit_comp64.c
@@ -792,17 +792,25 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, 
struct codegen_context *
                        else
                                EMIT(PPC_RAW_LWARX(tmp2_reg, tmp1_reg, dst_reg, 
0));
 
+                       /* Save old value in _R0 */
+                       if (imm & BPF_FETCH)
+                               EMIT(PPC_RAW_MR(_R0, tmp2_reg));
+
                        switch (imm) {
                        case BPF_ADD:
+                       case BPF_ADD | BPF_FETCH:
                                EMIT(PPC_RAW_ADD(tmp2_reg, tmp2_reg, src_reg));
                                break;
                        case BPF_AND:
+                       case BPF_AND | BPF_FETCH:
                                EMIT(PPC_RAW_AND(tmp2_reg, tmp2_reg, src_reg));
                                break;
                        case BPF_OR:
+                       case BPF_OR | BPF_FETCH:
                                EMIT(PPC_RAW_OR(tmp2_reg, tmp2_reg, src_reg));
                                break;
                        case BPF_XOR:
+                       case BPF_XOR | BPF_FETCH:
                                EMIT(PPC_RAW_XOR(tmp2_reg, tmp2_reg, src_reg));
                                break;
                        default:
@@ -812,13 +820,17 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, 
struct codegen_context *
                                return -EOPNOTSUPP;
                        }
 
-                       /* store result back */
+                       /* store new value */
                        if (size == BPF_DW)
                                EMIT(PPC_RAW_STDCX(tmp2_reg, tmp1_reg, 
dst_reg));
                        else
                                EMIT(PPC_RAW_STWCX(tmp2_reg, tmp1_reg, 
dst_reg));
                        /* we're done if this succeeded */
                        PPC_BCC_SHORT(COND_NE, tmp_idx);
+
+                       /* For the BPF_FETCH variant, get old value into 
src_reg */
+                       if (imm & BPF_FETCH)
+                               EMIT(PPC_RAW_MR(src_reg, _R0));
                        break;
 
                /*
-- 
2.35.1