[PATCH net-next 1/2] PPC: net: bpf_jit_comp: add XOR instruction for BPF JIT

[Daniel Borkmann <dxchgb@gmail.com>]

This patch is a follow-up for patch "filter: add XOR instruction for use
with X/K" that implements BPF PowerPC JIT parts for the BPF XOR operation.

Signed-off-by: Daniel Borkmann <daniel.borkmann@tik.ee.ethz.ch>
Cc: Matt Evans <matt@ozlabs.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
 Disclaimer: uncompiled and untested, since I don't have a PPC machine,
 but it should (hopefully) integrate cleanly; impl. after PPC instruction
 reference.

 arch/powerpc/include/asm/ppc-opcode.h |    3 +++
 arch/powerpc/net/bpf_jit.h            |    6 ++++++
 arch/powerpc/net/bpf_jit_comp.c       |   11 +++++++++++
 3 files changed, 20 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h
index 5f73ce6..42b1f43 100644
--- a/arch/powerpc/include/asm/ppc-opcode.h
+++ b/arch/powerpc/include/asm/ppc-opcode.h
@@ -168,9 +168,12 @@
 #define PPC_INST_AND			0x7c000038
 #define PPC_INST_ANDDOT			0x7c000039
 #define PPC_INST_OR			0x7c000378
+#define PPC_INST_XOR			0x7c000278
 #define PPC_INST_ANDI			0x70000000
 #define PPC_INST_ORI			0x60000000
 #define PPC_INST_ORIS			0x64000000
+#define PPC_INST_XORI			0x68000000
+#define PPC_INST_XORIS			0x6c000000
 #define PPC_INST_NEG			0x7c0000d0
 #define PPC_INST_BRANCH			0x48000000
 #define PPC_INST_BRANCH_COND		0x40800000
diff --git a/arch/powerpc/net/bpf_jit.h b/arch/powerpc/net/bpf_jit.h
index 1fc8109..8a5dfaf 100644
--- a/arch/powerpc/net/bpf_jit.h
+++ b/arch/powerpc/net/bpf_jit.h
@@ -134,6 +134,12 @@ DECLARE_LOAD_FUNC(sk_load_byte_msh);
 				     ___PPC_RS(a) | IMM_L(i))
 #define PPC_ORIS(d, a, i)	EMIT(PPC_INST_ORIS | ___PPC_RA(d) |	      \
 				     ___PPC_RS(a) | IMM_L(i))
+#define PPC_XOR(d, a, b)	EMIT(PPC_INST_XOR | ___PPC_RA(d) |	      \
+				     ___PPC_RS(a) | ___PPC_RB(b))
+#define PPC_XORI(d, a, i)	EMIT(PPC_INST_XORI | ___PPC_RA(d) |	      \
+				     ___PPC_RS(a) | IMM_L(i))
+#define PPC_XORIS(d, a, i)	EMIT(PPC_INST_XORIS | ___PPC_RA(d) |	      \
+				     ___PPC_RS(a) | IMM_L(i))
 #define PPC_SLW(d, a, s)	EMIT(PPC_INST_SLW | ___PPC_RA(d) |	      \
 				     ___PPC_RS(a) | ___PPC_RB(s))
 #define PPC_SRW(d, a, s)	EMIT(PPC_INST_SRW | ___PPC_RA(d) |	      \
diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index dd11306..b9434de 100644
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -232,6 +232,17 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image,
 			if (K >= 65536)
 				PPC_ORIS(r_A, r_A, IMM_H(K));
 			break;
+		case BPF_S_ANC_ALU_XOR_X:
+		case BPF_S_ALU_XOR_X: /* A ^= X */
+			ctx->seen |= SEEN_XREG;
+			PPC_XOR(r_A, r_A, r_X);
+			break;
+		case BPF_S_ALU_XOR_K: /* A ^= K */
+			if (IMM_L(K))
+				PPC_XORI(r_A, r_A, IMM_L(K));
+			if (K >= 65536)
+				PPC_XORIS(r_A, r_A, IMM_H(K));
+			break;
 		case BPF_S_ALU_LSH_X: /* A <<= X; */
 			ctx->seen |= SEEN_XREG;
 			PPC_SLW(r_A, r_A, r_X);