[PATCH -next 2/2] riscv, bpf: Support riscv jit to provide bpf_line_info

[Pu Lehui]

Add support for riscv jit to provide bpf_line_info.
We need to consider the prologue offset in ctx->offset,
but unlike x86 and arm64, ctx->offset of riscv does not
provide an extra slot for the prologue, so here we just
calculate the len of prologue and add it to ctx->offset
at the end. Both RV64 and RV32 have been tested.

Signed-off-by: Pu Lehui <pulehui at huawei.com>
---
 arch/riscv/net/bpf_jit.h      | 1 +
 arch/riscv/net/bpf_jit_core.c | 7 ++++++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/net/bpf_jit.h b/arch/riscv/net/bpf_jit.h
index 2a3715bf29fe..7dbbad7595f0 100644
--- a/arch/riscv/net/bpf_jit.h
+++ b/arch/riscv/net/bpf_jit.h
@@ -69,6 +69,7 @@ struct rv_jit_context {
 	struct bpf_prog *prog;
 	u16 *insns;		/* RV insns */
 	int ninsns;
+	int prologue_offset;
 	int epilogue_offset;
 	int *offset;		/* BPF to RV */
 	int nexentries;
diff --git a/arch/riscv/net/bpf_jit_core.c b/arch/riscv/net/bpf_jit_core.c
index be743d700aa7..6383eb591b0d 100644
--- a/arch/riscv/net/bpf_jit_core.c
+++ b/arch/riscv/net/bpf_jit_core.c
@@ -44,7 +44,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
 	unsigned int prog_size = 0, extable_size = 0;
 	bool tmp_blinded = false, extra_pass = false;
 	struct bpf_prog *tmp, *orig_prog = prog;
-	int pass = 0, prev_ninsns = 0, i;
+	int pass = 0, prev_ninsns = 0, prologue_len, i;
 	struct rv_jit_data *jit_data;
 	struct rv_jit_context *ctx;
 
@@ -95,6 +95,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
 			prog = orig_prog;
 			goto out_offset;
 		}
+		ctx->prologue_offset = ctx->ninsns;
 		bpf_jit_build_prologue(ctx);
 		ctx->epilogue_offset = ctx->ninsns;
 		bpf_jit_build_epilogue(ctx);
@@ -161,6 +162,10 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
 
 	if (!prog->is_func || extra_pass) {
 		bpf_jit_binary_lock_ro(jit_data->header);
+		prologue_len = ctx->epilogue_offset - ctx->prologue_offset;
+		for (i = 0; i < prog->len; i++)
+			ctx->offset[i] = ninsns_rvoff(prologue_len + ctx->offset[i]);
+		bpf_prog_fill_jited_linfo(prog, ctx->offset);
 out_offset:
 		kfree(ctx->offset);
 		kfree(jit_data);
-- 
2.25.1