sparc: Correct ctx->saw_frame_pointer logic.

We need to initialize the frame pointer register not just if it is
seen as a source operand, but also if it is seen as the destination
operand of a store or an atomic instruction (which effectively is a
source operand).

This is exercised by test_verifier's "non-invalid fp arithmetic"

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

arch/sparc/net/bpf_jit_comp_64.c

@@ -1270,6 +1270,9 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
 		const u8 tmp2 = bpf2sparc[TMP_REG_2];
 		u32 opcode = 0, rs2;
 
+		if (insn->dst_reg == BPF_REG_FP)
+			ctx->saw_frame_pointer = true;
+
 		ctx->tmp_2_used = true;
 		emit_loadimm(imm, tmp2, ctx);
 
@@ -1308,6 +1311,9 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
 		const u8 tmp = bpf2sparc[TMP_REG_1];
 		u32 opcode = 0, rs2;
 
+		if (insn->dst_reg == BPF_REG_FP)
+			ctx->saw_frame_pointer = true;
+
 		switch (BPF_SIZE(code)) {
 		case BPF_W:
 			opcode = ST32;
@@ -1340,6 +1346,9 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
 		const u8 tmp2 = bpf2sparc[TMP_REG_2];
 		const u8 tmp3 = bpf2sparc[TMP_REG_3];
 
+		if (insn->dst_reg == BPF_REG_FP)
+			ctx->saw_frame_pointer = true;
+
 		ctx->tmp_1_used = true;
 		ctx->tmp_2_used = true;
 		ctx->tmp_3_used = true;
@@ -1360,6 +1369,9 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
 		const u8 tmp2 = bpf2sparc[TMP_REG_2];
 		const u8 tmp3 = bpf2sparc[TMP_REG_3];
 
+		if (insn->dst_reg == BPF_REG_FP)
+			ctx->saw_frame_pointer = true;
+
 		ctx->tmp_1_used = true;
 		ctx->tmp_2_used = true;
 		ctx->tmp_3_used = true;