[DTrace-devel] [PATCH v2 1/4] dtrace: move get_member() to dt_cg.c

[Alan Maguire]

It will be used by both dt_prov_ip.c and dt_prov_tcp.c.

Signed-off-by: Alan Maguire <alan.maguire at oracle.com>
---
 libdtrace/dt_cg.c      | 39 ++++++++++++++++++++++++++++++++++++
 libdtrace/dt_cg.h      |  2 ++
 libdtrace/dt_prov_ip.c | 45 ++++--------------------------------------
 3 files changed, 45 insertions(+), 41 deletions(-)

diff --git a/libdtrace/dt_cg.c b/libdtrace/dt_cg.c
index c68a5d45..ad761d3b 100644
--- a/libdtrace/dt_cg.c
+++ b/libdtrace/dt_cg.c
@@ -1901,6 +1901,45 @@ dt_cg_ctf_offsetof(const char *structname, const char *membername,
 	return (ctm.ctm_offset / NBBY);
 }
 
+/*
+ * Retrieve the value of a member in a given struct.
+ *
+ * Entry:
+ *      reg = TYPE *ptr
+ *
+ * Return:
+ *      %r0 = ptr->member
+ * Clobbers:
+ *      %r1 .. %r5
+ */
+int
+dt_cg_get_member(dt_pcb_t *pcb, const char *name, int reg,
+		 const char *member)
+{
+	dtrace_hdl_t		*dtp = pcb->pcb_hdl;
+	dt_irlist_t		*dlp = &pcb->pcb_ir;
+	dtrace_typeinfo_t	tt;
+	ctf_membinfo_t		ctm;
+	size_t			size;
+	uint_t			ldop;
+
+	if (dtrace_lookup_by_type(dtp, DTRACE_OBJ_KMODS, name, &tt) == -1 ||
+	    ctf_member_info(tt.dtt_ctfp, tt.dtt_type, member, &ctm) == CTF_ERR)
+		return -1;
+
+	ldop = dt_cg_ldsize(NULL, tt.dtt_ctfp, ctm.ctm_type, &size);
+
+	emit(dlp, BPF_MOV_REG(BPF_REG_3, reg));
+	emit(dlp, BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, ctm.ctm_offset / NBBY));
+	emit(dlp, BPF_MOV_IMM(BPF_REG_2, size));
+	emit(dlp, BPF_MOV_REG(BPF_REG_1, BPF_REG_FP));
+	emit(dlp, BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, DT_TRAMP_SP_BASE));
+	emit(dlp, BPF_CALL_HELPER(dtp->dt_bpfhelper[BPF_FUNC_probe_read_kernel]));
+	emit(dlp, BPF_LOAD(ldop, BPF_REG_0, BPF_REG_FP, DT_TRAMP_SP_BASE));
+
+	return 0;
+}
+
 static void
 dt_cg_act_breakpoint(dt_pcb_t *pcb, dt_node_t *dnp, dtrace_actkind_t kind)
 {
diff --git a/libdtrace/dt_cg.h b/libdtrace/dt_cg.h
index fb26c125..c4aa610a 100644
--- a/libdtrace/dt_cg.h
+++ b/libdtrace/dt_cg.h
@@ -43,6 +43,8 @@ extern void dt_cg_tramp_epilogue_advance(dt_pcb_t *pcb, dt_activity_t act);
 extern void dt_cg_tramp_error(dt_pcb_t *pcb);
 extern int dt_cg_ctf_offsetof(const char *structname, const char *membername,
 			      size_t *sizep, int relaxed);
+extern int dt_cg_get_member(dt_pcb_t *pcb, const char *name, int reg,
+			    const char *member);
 extern uint_t dt_cg_ldsize(dt_node_t *dnp, ctf_file_t *ctfp, ctf_id_t type,
 			 ssize_t *ret_size);
 extern uint_t bpf_ldst_size(ssize_t size, int store);
diff --git a/libdtrace/dt_prov_ip.c b/libdtrace/dt_prov_ip.c
index c4a3a6e2..37f91e3d 100644
--- a/libdtrace/dt_prov_ip.c
+++ b/libdtrace/dt_prov_ip.c
@@ -62,43 +62,6 @@ static int populate(dtrace_hdl_t *dtp)
 			       probe_args, probes);
 }
 
-/*
- * Retrieve the value of a member in a given struct.
- *
- * Entry:
- *	reg = TYPE *ptr
- *
- * Return:
- *	%r0 = ptr->member
- * Clobbers:
- *	%r1 .. %r5
- */
-static int get_member(dt_pcb_t *pcb, const char *name, int reg,
-		      const char *member) {
-	dtrace_hdl_t		*dtp = pcb->pcb_hdl;
-	dt_irlist_t		*dlp = &pcb->pcb_ir;
-	dtrace_typeinfo_t	tt;
-	ctf_membinfo_t		ctm;
-	size_t			size;
-	uint_t			ldop;
-
-	if (dtrace_lookup_by_type(dtp, DTRACE_OBJ_KMODS, name, &tt) == -1 ||
-	    ctf_member_info(tt.dtt_ctfp, tt.dtt_type, member, &ctm) == CTF_ERR)
-		return -1;
-
-	ldop = dt_cg_ldsize(NULL, tt.dtt_ctfp, ctm.ctm_type, &size);
-
-	emit(dlp, BPF_MOV_REG(BPF_REG_3, reg));
-	emit(dlp, BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, ctm.ctm_offset / NBBY));
-	emit(dlp, BPF_MOV_IMM(BPF_REG_2, size));
-	emit(dlp, BPF_MOV_REG(BPF_REG_1, BPF_REG_FP));
-	emit(dlp, BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, DT_TRAMP_SP_BASE));
-	emit(dlp, BPF_CALL_HELPER(dtp->dt_bpfhelper[BPF_FUNC_probe_read_kernel]));
-	emit(dlp, BPF_LOAD(ldop, BPF_REG_0, BPF_REG_FP, DT_TRAMP_SP_BASE));
-
-	return 0;
-}
-
 /*
  * Generate a BPF trampoline for a SDT probe.
  *
@@ -142,7 +105,7 @@ static int trampoline(dt_pcb_t *pcb, uint_t exitlbl)
 
 	emit(dlp, BPF_STORE(BPF_DW, BPF_REG_7, DMST_ARG(0), BPF_REG_6));
 
-	get_member(pcb, "struct sk_buff", BPF_REG_6, "sk");
+	dt_cg_get_member(pcb, "struct sk_buff", BPF_REG_6, "sk");
 	emit(dlp, BPF_STORE(BPF_DW, BPF_REG_7, DMST_ARG(1), BPF_REG_0));
 
 	/*
@@ -150,11 +113,11 @@ static int trampoline(dt_pcb_t *pcb, uint_t exitlbl)
 	 *	skb_network_header(skb)	=	(include/linux/ip.h)
 	 *	skb->head + skb->network_header	(include/linux/skbuff.h)
 	 */
-	get_member(pcb, "struct sk_buff", BPF_REG_6, "head");
+	dt_cg_get_member(pcb, "struct sk_buff", BPF_REG_6, "head");
 	emit(dlp, BPF_STORE(BPF_DW, BPF_REG_7, DMST_ARG(2), BPF_REG_0));
 	emit(dlp, BPF_STORE(BPF_DW, BPF_REG_7, DMST_ARG(4), BPF_REG_0));
 	emit(dlp, BPF_STORE(BPF_DW, BPF_REG_7, DMST_ARG(5), BPF_REG_0));
-	get_member(pcb, "struct sk_buff", BPF_REG_6, "network_header");
+	dt_cg_get_member(pcb, "struct sk_buff", BPF_REG_6, "network_header");
 	emit(dlp, BPF_XADD_REG(BPF_DW, BPF_REG_7, DMST_ARG(2), BPF_REG_0));
 	emit(dlp, BPF_XADD_REG(BPF_DW, BPF_REG_7, DMST_ARG(4), BPF_REG_0));
 	emit(dlp, BPF_XADD_REG(BPF_DW, BPF_REG_7, DMST_ARG(5), BPF_REG_0));
@@ -168,7 +131,7 @@ static int trampoline(dt_pcb_t *pcb, uint_t exitlbl)
 	else
 		emit(dlp, BPF_STORE_IMM(BPF_DW, BPF_REG_7, DMST_ARG(5), 0));
 
-	get_member(pcb, "struct sk_buff", BPF_REG_6, "dev");
+	dt_cg_get_member(pcb, "struct sk_buff", BPF_REG_6, "dev");
 	emit(dlp, BPF_STORE(BPF_DW, BPF_REG_7, DMST_ARG(3), BPF_REG_0));
 
 	return 0;
-- 
2.39.3