Provide ksw_stack_init() and ksw_stack_exit() to manage entry and exit
probes for the target function from ksw_get_config().
Signed-off-by: Jinchao Wang <wangjinchao600@gmail.com>
---
mm/kstackwatch/kstackwatch.h | 4 ++
mm/kstackwatch/stack.c | 101 +++++++++++++++++++++++++++++++++++
2 files changed, 105 insertions(+)
diff --git a/mm/kstackwatch/kstackwatch.h b/mm/kstackwatch/kstackwatch.h
index 850fc2b18a9c..4045890e5652 100644
--- a/mm/kstackwatch/kstackwatch.h
+++ b/mm/kstackwatch/kstackwatch.h
@@ -35,6 +35,10 @@ struct ksw_config {
// singleton, only modified in kernel.c
const struct ksw_config *ksw_get_config(void);
+/* stack management */
+int ksw_stack_init(void);
+void ksw_stack_exit(void);
+
/* watch management */
struct ksw_watchpoint {
struct perf_event *__percpu *event;
diff --git a/mm/kstackwatch/stack.c b/mm/kstackwatch/stack.c
index cec594032515..9f59f41d954c 100644
--- a/mm/kstackwatch/stack.c
+++ b/mm/kstackwatch/stack.c
@@ -1 +1,102 @@
// SPDX-License-Identifier: GPL-2.0
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/atomic.h>
+#include <linux/fprobe.h>
+#include <linux/kprobes.h>
+#include <linux/kstackwatch_types.h>
+#include <linux/printk.h>
+
+#include "kstackwatch.h"
+
+static struct kprobe entry_probe;
+static struct fprobe exit_probe;
+
+static int ksw_stack_prepare_watch(struct pt_regs *regs,
+ const struct ksw_config *config,
+ ulong *watch_addr, u16 *watch_len)
+{
+ /* implement logic will be added in following patches */
+ *watch_addr = 0;
+ *watch_len = 0;
+ return 0;
+}
+
+static void ksw_stack_entry_handler(struct kprobe *p, struct pt_regs *regs,
+ unsigned long flags)
+{
+ struct ksw_ctx *ctx = ¤t->ksw_ctx;
+ ulong watch_addr;
+ u16 watch_len;
+ int ret;
+
+ ret = ksw_watch_get(&ctx->wp);
+ if (ret)
+ return;
+
+ ret = ksw_stack_prepare_watch(regs, ksw_get_config(), &watch_addr,
+ &watch_len);
+ if (ret) {
+ ksw_watch_off(ctx->wp);
+ ctx->wp = NULL;
+ pr_err("failed to prepare watch target: %d\n", ret);
+ return;
+ }
+
+ ret = ksw_watch_on(ctx->wp, watch_addr, watch_len);
+ if (ret) {
+ pr_err("failed to watch on depth:%d addr:0x%lx len:%u %d\n",
+ ksw_get_config()->depth, watch_addr, watch_len, ret);
+ return;
+ }
+
+}
+
+static void ksw_stack_exit_handler(struct fprobe *fp, unsigned long ip,
+ unsigned long ret_ip,
+ struct ftrace_regs *regs, void *data)
+{
+ struct ksw_ctx *ctx = ¤t->ksw_ctx;
+
+
+ if (ctx->wp) {
+ ksw_watch_off(ctx->wp);
+ ctx->wp = NULL;
+ ctx->sp = 0;
+ }
+}
+
+int ksw_stack_init(void)
+{
+ int ret;
+ char *symbuf = NULL;
+
+ memset(&entry_probe, 0, sizeof(entry_probe));
+ entry_probe.symbol_name = ksw_get_config()->func_name;
+ entry_probe.offset = ksw_get_config()->func_offset;
+ entry_probe.post_handler = ksw_stack_entry_handler;
+ ret = register_kprobe(&entry_probe);
+ if (ret) {
+ pr_err("failed to register kprobe ret %d\n", ret);
+ return ret;
+ }
+
+ memset(&exit_probe, 0, sizeof(exit_probe));
+ exit_probe.exit_handler = ksw_stack_exit_handler;
+ symbuf = (char *)ksw_get_config()->func_name;
+
+ ret = register_fprobe_syms(&exit_probe, (const char **)&symbuf, 1);
+ if (ret < 0) {
+ pr_err("failed to register fprobe ret %d\n", ret);
+ unregister_kprobe(&entry_probe);
+ return ret;
+ }
+
+ return 0;
+}
+
+void ksw_stack_exit(void)
+{
+ unregister_fprobe(&exit_probe);
+ unregister_kprobe(&entry_probe);
+}
--
2.43.0