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Message-Id: <169556265707.146934.9759320469271410104.stgit@devnote2>
Date: Sun, 24 Sep 2023 22:37:37 +0900
From: "Masami Hiramatsu (Google)" <mhiramat@...nel.org>
To: Alexei Starovoitov <alexei.starovoitov@...il.com>,
Steven Rostedt <rostedt@...dmis.org>,
Florent Revest <revest@...omium.org>
Cc: linux-trace-kernel@...r.kernel.org,
LKML <linux-kernel@...r.kernel.org>,
Martin KaFai Lau <martin.lau@...ux.dev>,
bpf <bpf@...r.kernel.org>, Sven Schnelle <svens@...ux.ibm.com>,
Alexei Starovoitov <ast@...nel.org>,
Jiri Olsa <jolsa@...nel.org>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
Alan Maguire <alan.maguire@...cle.com>,
Mark Rutland <mark.rutland@....com>,
Peter Zijlstra <peterz@...radead.org>,
Thomas Gleixner <tglx@...utronix.de>,
Guo Ren <guoren@...nel.org>
Subject: [PATCH v5 09/12] tracing/fprobe: Enable fprobe events with CONFIG_DYNAMIC_FTRACE_WITH_ARGS
From: Masami Hiramatsu (Google) <mhiramat@...nel.org>
Allow fprobe events to be enabled with CONFIG_DYNAMIC_FTRACE_WITH_ARGS.
With this change, fprobe events mostly use ftrace_regs instead of pt_regs.
Note that if the arch doesn't enable HAVE_PT_REGS_COMPAT_FTRACE_REGS,
fprobe events will not be able to be used from perf.
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@...nel.org>
---
Changes in v3:
- introduce ftrace_regs_get_kernel_stack_nth().
- fix typo.
Changes in v4:
- Use per-cpu pt_regs stack and ftrace_partial_regs() for perf event.
Changes in v5:
- Use perf's per-cpu pt_regs.
- Use new ftrace_fill_perf_regs() to fill perf required regs.
---
include/linux/ftrace.h | 15 ++++++++
kernel/trace/Kconfig | 1 -
kernel/trace/trace_fprobe.c | 74 ++++++++++++++++++++-------------------
kernel/trace/trace_probe_tmpl.h | 2 +
4 files changed, 53 insertions(+), 39 deletions(-)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 962c3e6c5e3b..3748c8100924 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -233,6 +233,21 @@ static __always_inline bool ftrace_regs_has_args(struct ftrace_regs *fregs)
return ftrace_get_regs(fregs) != NULL;
}
+#ifdef CONFIG_HAVE_REGS_AND_STACK_ACCESS_API
+static __always_inline unsigned long
+ftrace_regs_get_kernel_stack_nth(struct ftrace_regs *fregs, unsigned int nth)
+{
+ unsigned long *stackp;
+
+ stackp = (unsigned long *)ftrace_regs_get_stack_pointer(fregs);
+ if (((unsigned long)(stackp + nth) & ~(THREAD_SIZE - 1)) ==
+ ((unsigned long)stackp & ~(THREAD_SIZE - 1)))
+ return *(stackp + nth);
+
+ return 0;
+}
+#endif /* CONFIG_HAVE_REGS_AND_STACK_ACCESS_API */
+
#ifdef CONFIG_FUNCTION_TRACER
extern int ftrace_enabled;
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index d56304276318..6fb4ecf8767d 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -679,7 +679,6 @@ config FPROBE_EVENTS
select TRACING
select PROBE_EVENTS
select DYNAMIC_EVENTS
- depends on DYNAMIC_FTRACE_WITH_REGS
default y
help
This allows user to add tracing events on the function entry and
diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c
index c60d0d9f1a95..882c220333cc 100644
--- a/kernel/trace/trace_fprobe.c
+++ b/kernel/trace/trace_fprobe.c
@@ -132,7 +132,7 @@ static int
process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
void *base)
{
- struct pt_regs *regs = rec;
+ struct ftrace_regs *fregs = rec;
unsigned long val;
int ret;
@@ -140,17 +140,17 @@ process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
/* 1st stage: get value from context */
switch (code->op) {
case FETCH_OP_STACK:
- val = regs_get_kernel_stack_nth(regs, code->param);
+ val = ftrace_regs_get_kernel_stack_nth(fregs, code->param);
break;
case FETCH_OP_STACKP:
- val = kernel_stack_pointer(regs);
+ val = ftrace_regs_get_stack_pointer(fregs);
break;
case FETCH_OP_RETVAL:
- val = regs_return_value(regs);
+ val = ftrace_regs_return_value(fregs);
break;
#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
case FETCH_OP_ARG:
- val = regs_get_kernel_argument(regs, code->param);
+ val = ftrace_regs_get_argument(fregs, code->param);
break;
#endif
case FETCH_NOP_SYMBOL: /* Ignore a place holder */
@@ -170,7 +170,7 @@ NOKPROBE_SYMBOL(process_fetch_insn)
/* function entry handler */
static nokprobe_inline void
__fentry_trace_func(struct trace_fprobe *tf, unsigned long entry_ip,
- struct pt_regs *regs,
+ struct ftrace_regs *fregs,
struct trace_event_file *trace_file)
{
struct fentry_trace_entry_head *entry;
@@ -184,36 +184,36 @@ __fentry_trace_func(struct trace_fprobe *tf, unsigned long entry_ip,
if (trace_trigger_soft_disabled(trace_file))
return;
- dsize = __get_data_size(&tf->tp, regs);
+ dsize = __get_data_size(&tf->tp, fregs);
entry = trace_event_buffer_reserve(&fbuffer, trace_file,
sizeof(*entry) + tf->tp.size + dsize);
if (!entry)
return;
- fbuffer.regs = regs;
+ fbuffer.regs = ftrace_get_regs(fregs);
entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
entry->ip = entry_ip;
- store_trace_args(&entry[1], &tf->tp, regs, sizeof(*entry), dsize);
+ store_trace_args(&entry[1], &tf->tp, fregs, sizeof(*entry), dsize);
trace_event_buffer_commit(&fbuffer);
}
static void
fentry_trace_func(struct trace_fprobe *tf, unsigned long entry_ip,
- struct pt_regs *regs)
+ struct ftrace_regs *fregs)
{
struct event_file_link *link;
trace_probe_for_each_link_rcu(link, &tf->tp)
- __fentry_trace_func(tf, entry_ip, regs, link->file);
+ __fentry_trace_func(tf, entry_ip, fregs, link->file);
}
NOKPROBE_SYMBOL(fentry_trace_func);
/* Kretprobe handler */
static nokprobe_inline void
__fexit_trace_func(struct trace_fprobe *tf, unsigned long entry_ip,
- unsigned long ret_ip, struct pt_regs *regs,
+ unsigned long ret_ip, struct ftrace_regs *fregs,
struct trace_event_file *trace_file)
{
struct fexit_trace_entry_head *entry;
@@ -227,60 +227,63 @@ __fexit_trace_func(struct trace_fprobe *tf, unsigned long entry_ip,
if (trace_trigger_soft_disabled(trace_file))
return;
- dsize = __get_data_size(&tf->tp, regs);
+ dsize = __get_data_size(&tf->tp, fregs);
entry = trace_event_buffer_reserve(&fbuffer, trace_file,
sizeof(*entry) + tf->tp.size + dsize);
if (!entry)
return;
- fbuffer.regs = regs;
+ fbuffer.regs = ftrace_get_regs(fregs);
entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
entry->func = entry_ip;
entry->ret_ip = ret_ip;
- store_trace_args(&entry[1], &tf->tp, regs, sizeof(*entry), dsize);
+ store_trace_args(&entry[1], &tf->tp, fregs, sizeof(*entry), dsize);
trace_event_buffer_commit(&fbuffer);
}
static void
fexit_trace_func(struct trace_fprobe *tf, unsigned long entry_ip,
- unsigned long ret_ip, struct pt_regs *regs)
+ unsigned long ret_ip, struct ftrace_regs *fregs)
{
struct event_file_link *link;
trace_probe_for_each_link_rcu(link, &tf->tp)
- __fexit_trace_func(tf, entry_ip, ret_ip, regs, link->file);
+ __fexit_trace_func(tf, entry_ip, ret_ip, fregs, link->file);
}
NOKPROBE_SYMBOL(fexit_trace_func);
#ifdef CONFIG_PERF_EVENTS
static int fentry_perf_func(struct trace_fprobe *tf, unsigned long entry_ip,
- struct pt_regs *regs)
+ struct ftrace_regs *fregs)
{
struct trace_event_call *call = trace_probe_event_call(&tf->tp);
struct fentry_trace_entry_head *entry;
struct hlist_head *head;
int size, __size, dsize;
+ struct pt_regs *regs;
int rctx;
head = this_cpu_ptr(call->perf_events);
if (hlist_empty(head))
return 0;
- dsize = __get_data_size(&tf->tp, regs);
+ dsize = __get_data_size(&tf->tp, fregs);
__size = sizeof(*entry) + tf->tp.size + dsize;
size = ALIGN(__size + sizeof(u32), sizeof(u64));
size -= sizeof(u32);
- entry = perf_trace_buf_alloc(size, NULL, &rctx);
+ entry = perf_trace_buf_alloc(size, ®s, &rctx);
if (!entry)
return 0;
+ regs = ftrace_fill_perf_regs(fregs, regs);
+
entry->ip = entry_ip;
memset(&entry[1], 0, dsize);
- store_trace_args(&entry[1], &tf->tp, regs, sizeof(*entry), dsize);
+ store_trace_args(&entry[1], &tf->tp, fregs, sizeof(*entry), dsize);
perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
head, NULL);
return 0;
@@ -289,30 +292,33 @@ NOKPROBE_SYMBOL(fentry_perf_func);
static void
fexit_perf_func(struct trace_fprobe *tf, unsigned long entry_ip,
- unsigned long ret_ip, struct pt_regs *regs)
+ unsigned long ret_ip, struct ftrace_regs *fregs)
{
struct trace_event_call *call = trace_probe_event_call(&tf->tp);
struct fexit_trace_entry_head *entry;
struct hlist_head *head;
int size, __size, dsize;
+ struct pt_regs *regs;
int rctx;
head = this_cpu_ptr(call->perf_events);
if (hlist_empty(head))
return;
- dsize = __get_data_size(&tf->tp, regs);
+ dsize = __get_data_size(&tf->tp, fregs);
__size = sizeof(*entry) + tf->tp.size + dsize;
size = ALIGN(__size + sizeof(u32), sizeof(u64));
size -= sizeof(u32);
- entry = perf_trace_buf_alloc(size, NULL, &rctx);
+ entry = perf_trace_buf_alloc(size, ®s, &rctx);
if (!entry)
return;
+ regs = ftrace_fill_perf_regs(fregs, regs);
+
entry->func = entry_ip;
entry->ret_ip = ret_ip;
- store_trace_args(&entry[1], &tf->tp, regs, sizeof(*entry), dsize);
+ store_trace_args(&entry[1], &tf->tp, fregs, sizeof(*entry), dsize);
perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
head, NULL);
}
@@ -324,17 +330,14 @@ static int fentry_dispatcher(struct fprobe *fp, unsigned long entry_ip,
void *entry_data)
{
struct trace_fprobe *tf = container_of(fp, struct trace_fprobe, fp);
- struct pt_regs *regs = ftrace_get_regs(fregs);
int ret = 0;
- if (!regs)
- return 0;
-
if (trace_probe_test_flag(&tf->tp, TP_FLAG_TRACE))
- fentry_trace_func(tf, entry_ip, regs);
+ fentry_trace_func(tf, entry_ip, fregs);
+
#ifdef CONFIG_PERF_EVENTS
if (trace_probe_test_flag(&tf->tp, TP_FLAG_PROFILE))
- ret = fentry_perf_func(tf, entry_ip, regs);
+ ret = fentry_perf_func(tf, entry_ip, fregs);
#endif
return ret;
}
@@ -345,16 +348,13 @@ static void fexit_dispatcher(struct fprobe *fp, unsigned long entry_ip,
void *entry_data)
{
struct trace_fprobe *tf = container_of(fp, struct trace_fprobe, fp);
- struct pt_regs *regs = ftrace_get_regs(fregs);
-
- if (!regs)
- return;
if (trace_probe_test_flag(&tf->tp, TP_FLAG_TRACE))
- fexit_trace_func(tf, entry_ip, ret_ip, regs);
+ fexit_trace_func(tf, entry_ip, ret_ip, fregs);
+
#ifdef CONFIG_PERF_EVENTS
if (trace_probe_test_flag(&tf->tp, TP_FLAG_PROFILE))
- fexit_perf_func(tf, entry_ip, ret_ip, regs);
+ fexit_perf_func(tf, entry_ip, ret_ip, fregs);
#endif
}
NOKPROBE_SYMBOL(fexit_dispatcher);
diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h
index 3935b347f874..05445a745a07 100644
--- a/kernel/trace/trace_probe_tmpl.h
+++ b/kernel/trace/trace_probe_tmpl.h
@@ -232,7 +232,7 @@ process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val,
/* Sum up total data length for dynamic arrays (strings) */
static nokprobe_inline int
-__get_data_size(struct trace_probe *tp, struct pt_regs *regs)
+__get_data_size(struct trace_probe *tp, void *regs)
{
struct probe_arg *arg;
int i, len, ret = 0;
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