From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Tue, 6 Apr 2021 18:37:43 +0000 (-0400)
Subject: Add entryexit field to kretprobes ABI
X-Git-Tag: v2.13.0-rc1~28
X-Git-Url: https://git.lttng.org/?p=lttng-modules.git;a=commitdiff_plain;h=88a82b1744612c10d95ba86dec6f8919b325ec77

Add entryexit field to kretprobes ABI

At this stage, only "entryexit = 0" is supported. No behavior change
except for validating that ENTRY and EXIT are unsupported (-EINVAL).

It is possible to extend struct lttng_kernel_kretprobe because it is
always used within struct lttng_kernel_event which contains enough
zero-initialized padding due to char padding[LTTNG_KERNEL_EVENT_PADDING2].

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I96d86eebff66da4af186ef51c2ff13e2ed84a510
---

diff --git a/include/lttng/abi.h b/include/lttng/abi.h
index 0cdd6534..5745635e 100644
--- a/include/lttng/abi.h
+++ b/include/lttng/abi.h
@@ -56,11 +56,18 @@ struct lttng_kernel_channel {
 	char padding[LTTNG_KERNEL_CHANNEL_PADDING];
 } __attribute__((packed));
 
+enum lttng_kernel_kretprobe_entryexit {
+	LTTNG_KERNEL_KRETPROBE_ENTRYEXIT = 0,
+	LTTNG_KERNEL_KRETPROBE_ENTRY = 1,
+	LTTNG_KERNEL_KRETPROBE_EXIT = 2,
+};
+
 struct lttng_kernel_kretprobe {
 	uint64_t addr;
 
 	uint64_t offset;
 	char symbol_name[LTTNG_KERNEL_SYM_NAME_LEN];
+	uint8_t entryexit;	/* enum lttng_kernel_kretprobe_entryexit */
 } __attribute__((packed));
 
 /*
diff --git a/src/lttng-abi.c b/src/lttng-abi.c
index c06aa79a..eb68bce8 100644
--- a/src/lttng-abi.c
+++ b/src/lttng-abi.c
@@ -1746,9 +1746,19 @@ int lttng_abi_validate_event_param(struct lttng_kernel_event *event_param)
 		}
 		break;
 
+	case LTTNG_KERNEL_KRETPROBE:
+		switch (event_param->u.kretprobe.entryexit) {
+		case LTTNG_KERNEL_SYSCALL_ENTRYEXIT:
+			break;
+		case LTTNG_KERNEL_SYSCALL_ENTRY:	/* Fall-through */
+		case LTTNG_KERNEL_SYSCALL_EXIT:		/* Fall-through */
+		default:
+			return -EINVAL;
+		}
+		break;
+
 	case LTTNG_KERNEL_TRACEPOINT:	/* Fall-through */
 	case LTTNG_KERNEL_KPROBE:	/* Fall-through */
-	case LTTNG_KERNEL_KRETPROBE:	/* Fall-through */
 	case LTTNG_KERNEL_UPROBE:
 		break;