[PATCH 4.19 109/243] sparc: Correct ctx->saw_frame_pointer logic.

Greg Kroah-Hartman
2019-12-11T15:20:49Z

From: David Miller <davem@davemloft.net>

[ Upstream commit e2ac579a7a18bcd9e8cf14cf42eac0b8a2ba6c4b ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/sparc/net/bpf_jit_comp_64.c | 12 ++++++++++++
1 file changed, 12 insertions(+)

diff --git a/arch/sparc/net/bpf_jit_comp_64.c b/arch/sparc/net/bpf_jit_comp_64.c
index 7217d63596431..ec4da4dc98f12 100644
--- a/arch/sparc/net/bpf_jit_comp_64.c
+++ b/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;
--
2.20.1