Re: [PATCH v2 bpf-next 5/8] bpf: introduce BPF_RAW_TRACEPOINT

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 

On 3/23/18 4:13 PM, Daniel Borkmann wrote:

On 03/22/2018 04:41 PM, Alexei Starovoitov wrote:

On 3/22/18 2:43 AM, Daniel Borkmann wrote:

On 03/21/2018 07:54 PM, Alexei Starovoitov wrote:
[...]

@@ -546,6 +556,53 @@ extern void ftrace_profile_free_filter(struct perf_event *event);
 void perf_trace_buf_update(void *record, u16 type);
 void *perf_trace_buf_alloc(int size, struct pt_regs **regs, int *rctxp);

+void bpf_trace_run1(struct bpf_prog *prog, u64 arg1);
+void bpf_trace_run2(struct bpf_prog *prog, u64 arg1, u64 arg2);
+void bpf_trace_run3(struct bpf_prog *prog, u64 arg1, u64 arg2,
+            u64 arg3);
+void bpf_trace_run4(struct bpf_prog *prog, u64 arg1, u64 arg2,
+            u64 arg3, u64 arg4);
+void bpf_trace_run5(struct bpf_prog *prog, u64 arg1, u64 arg2,
+            u64 arg3, u64 arg4, u64 arg5);
+void bpf_trace_run6(struct bpf_prog *prog, u64 arg1, u64 arg2,
+            u64 arg3, u64 arg4, u64 arg5, u64 arg6);
+void bpf_trace_run7(struct bpf_prog *prog, u64 arg1, u64 arg2,
+            u64 arg3, u64 arg4, u64 arg5, u64 arg6, u64 arg7);
+void bpf_trace_run8(struct bpf_prog *prog, u64 arg1, u64 arg2,
+            u64 arg3, u64 arg4, u64 arg5, u64 arg6, u64 arg7,
+            u64 arg8);
+void bpf_trace_run9(struct bpf_prog *prog, u64 arg1, u64 arg2,
+            u64 arg3, u64 arg4, u64 arg5, u64 arg6, u64 arg7,
+            u64 arg8, u64 arg9);
+void bpf_trace_run10(struct bpf_prog *prog, u64 arg1, u64 arg2,
+             u64 arg3, u64 arg4, u64 arg5, u64 arg6, u64 arg7,
+             u64 arg8, u64 arg9, u64 arg10);
+void bpf_trace_run11(struct bpf_prog *prog, u64 arg1, u64 arg2,
+             u64 arg3, u64 arg4, u64 arg5, u64 arg6, u64 arg7,
+             u64 arg8, u64 arg9, u64 arg10, u64 arg11);
+void bpf_trace_run12(struct bpf_prog *prog, u64 arg1, u64 arg2,
+             u64 arg3, u64 arg4, u64 arg5, u64 arg6, u64 arg7,
+             u64 arg8, u64 arg9, u64 arg10, u64 arg11, u64 arg12);
+void bpf_trace_run13(struct bpf_prog *prog, u64 arg1, u64 arg2,
+             u64 arg3, u64 arg4, u64 arg5, u64 arg6, u64 arg7,
+             u64 arg8, u64 arg9, u64 arg10, u64 arg11, u64 arg12,
+             u64 arg13);
+void bpf_trace_run14(struct bpf_prog *prog, u64 arg1, u64 arg2,
+             u64 arg3, u64 arg4, u64 arg5, u64 arg6, u64 arg7,
+             u64 arg8, u64 arg9, u64 arg10, u64 arg11, u64 arg12,
+             u64 arg13, u64 arg14);
+void bpf_trace_run15(struct bpf_prog *prog, u64 arg1, u64 arg2,
+             u64 arg3, u64 arg4, u64 arg5, u64 arg6, u64 arg7,
+             u64 arg8, u64 arg9, u64 arg10, u64 arg11, u64 arg12,
+             u64 arg13, u64 arg14, u64 arg15);
+void bpf_trace_run16(struct bpf_prog *prog, u64 arg1, u64 arg2,
+             u64 arg3, u64 arg4, u64 arg5, u64 arg6, u64 arg7,
+             u64 arg8, u64 arg9, u64 arg10, u64 arg11, u64 arg12,
+             u64 arg13, u64 arg14, u64 arg15, u64 arg16);
+void bpf_trace_run17(struct bpf_prog *prog, u64 arg1, u64 arg2,
+             u64 arg3, u64 arg4, u64 arg5, u64 arg6, u64 arg7,
+             u64 arg8, u64 arg9, u64 arg10, u64 arg11, u64 arg12,
+             u64 arg13, u64 arg14, u64 arg15, u64 arg16, u64 arg17);
 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
                    struct trace_event_call *call, u64 count,
                    struct pt_regs *regs, struct hlist_head *head,

[...]

@@ -896,3 +976,206 @@ int perf_event_query_prog_array(struct perf_event *event, void __user *info)

     return ret;
 }
+
+static __always_inline
+void __bpf_trace_run(struct bpf_prog *prog, u64 *args)
+{
+    rcu_read_lock();
+    preempt_disable();
+    (void) BPF_PROG_RUN(prog, args);
+    preempt_enable();
+    rcu_read_unlock();
+}
+
+#define EVAL1(FN, X) FN(X)
+#define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y)
+#define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y)
+#define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y)
+#define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y)
+#define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y)
+
+#define COPY(X) args[X - 1] = arg##X;
+
+void bpf_trace_run1(struct bpf_prog *prog, u64 arg1)
+{
+    u64 args[1];
+
+    EVAL1(COPY, 1);
+    __bpf_trace_run(prog, args);
+}
+EXPORT_SYMBOL_GPL(bpf_trace_run1);
+void bpf_trace_run2(struct bpf_prog *prog, u64 arg1, u64 arg2)
+{
+    u64 args[2];
+
+    EVAL2(COPY, 1, 2);
+    __bpf_trace_run(prog, args);
+}
+EXPORT_SYMBOL_GPL(bpf_trace_run2);
+void bpf_trace_run3(struct bpf_prog *prog, u64 arg1, u64 arg2,
+            u64 arg3)
+{
+    u64 args[3];
+
+    EVAL3(COPY, 1, 2, 3);
+    __bpf_trace_run(prog, args);
+}
+EXPORT_SYMBOL_GPL(bpf_trace_run3);
+void bpf_trace_run4(struct bpf_prog *prog, u64 arg1, u64 arg2,
+            u64 arg3, u64 arg4)
+{
+    u64 args[4];
+
+    EVAL4(COPY, 1, 2, 3, 4);
+    __bpf_trace_run(prog, args);
+}
+EXPORT_SYMBOL_GPL(bpf_trace_run4);
+void bpf_trace_run5(struct bpf_prog *prog, u64 arg1, u64 arg2,
+            u64 arg3, u64 arg4, u64 arg5)
+{
+    u64 args[5];
+
+    EVAL5(COPY, 1, 2, 3, 4, 5);
+    __bpf_trace_run(prog, args);
+}
+EXPORT_SYMBOL_GPL(bpf_trace_run5);
+void bpf_trace_run6(struct bpf_prog *prog, u64 arg1, u64 arg2,
+            u64 arg3, u64 arg4, u64 arg5, u64 arg6)
+{
+    u64 args[6];
+
+    EVAL6(COPY, 1, 2, 3, 4, 5, 6);
+    __bpf_trace_run(prog, args);
+}
+EXPORT_SYMBOL_GPL(bpf_trace_run6);
+void bpf_trace_run7(struct bpf_prog *prog, u64 arg1, u64 arg2,
+            u64 arg3, u64 arg4, u64 arg5, u64 arg6, u64 arg7)
+{
+    u64 args[7];
+
+    EVAL6(COPY, 1, 2, 3, 4, 5, 6);
+    EVAL1(COPY, 7);
+    __bpf_trace_run(prog, args);
+}
+EXPORT_SYMBOL_GPL(bpf_trace_run7);
+void bpf_trace_run8(struct bpf_prog *prog, u64 arg1, u64 arg2,
+            u64 arg3, u64 arg4, u64 arg5, u64 arg6, u64 arg7,
+            u64 arg8)
+{
+    u64 args[8];
+
+    EVAL6(COPY, 1, 2, 3, 4, 5, 6);
+    EVAL2(COPY, 7, 8);
+    __bpf_trace_run(prog, args);
+}
+EXPORT_SYMBOL_GPL(bpf_trace_run8);
+void bpf_trace_run9(struct bpf_prog *prog, u64 arg1, u64 arg2,
+            u64 arg3, u64 arg4, u64 arg5, u64 arg6, u64 arg7,
+            u64 arg8, u64 arg9)
+{
+    u64 args[9];
+
+    EVAL6(COPY, 1, 2, 3, 4, 5, 6);
+    EVAL3(COPY, 7, 8, 9);
+    __bpf_trace_run(prog, args);
+}
+EXPORT_SYMBOL_GPL(bpf_trace_run9);
+void bpf_trace_run10(struct bpf_prog *prog, u64 arg1, u64 arg2,
+             u64 arg3, u64 arg4, u64 arg5, u64 arg6, u64 arg7,
+             u64 arg8, u64 arg9, u64 arg10)
+{
+    u64 args[10];
+
+    EVAL6(COPY, 1, 2, 3, 4, 5, 6);
+    EVAL4(COPY, 7, 8, 9, 10);
+    __bpf_trace_run(prog, args);
+}
+EXPORT_SYMBOL_GPL(bpf_trace_run10);
+void bpf_trace_run11(struct bpf_prog *prog, u64 arg1, u64 arg2,
+             u64 arg3, u64 arg4, u64 arg5, u64 arg6, u64 arg7,
+             u64 arg8, u64 arg9, u64 arg10, u64 arg11)
+{
+    u64 args[11];
+
+    EVAL6(COPY, 1, 2, 3, 4, 5, 6);
+    EVAL5(COPY, 7, 8, 9, 10, 11);
+    __bpf_trace_run(prog, args);
+}
+EXPORT_SYMBOL_GPL(bpf_trace_run11);
+void bpf_trace_run12(struct bpf_prog *prog, u64 arg1, u64 arg2,
+             u64 arg3, u64 arg4, u64 arg5, u64 arg6, u64 arg7,
+             u64 arg8, u64 arg9, u64 arg10, u64 arg11, u64 arg12)
+{
+    u64 args[12];
+
+    EVAL6(COPY, 1, 2, 3, 4, 5, 6);
+    EVAL6(COPY, 7, 8, 9, 10, 11, 12);
+    __bpf_trace_run(prog, args);
+}
+EXPORT_SYMBOL_GPL(bpf_trace_run12);
+void bpf_trace_run17(struct bpf_prog *prog, u64 arg1, u64 arg2,
+             u64 arg3, u64 arg4, u64 arg5, u64 arg6, u64 arg7,
+             u64 arg8, u64 arg9, u64 arg10, u64 arg11, u64 arg12,
+             u64 arg13, u64 arg14, u64 arg15, u64 arg16, u64 arg17)
+{
+    u64 args[17];
+
+    EVAL6(COPY, 1, 2, 3, 4, 5, 6);
+    EVAL6(COPY, 7, 8, 9, 10, 11, 12);
+    EVAL5(COPY, 13, 14, 15, 16, 17);
+    __bpf_trace_run(prog, args);
+}
+EXPORT_SYMBOL_GPL(bpf_trace_run17);


Would be nice if we could generate all these above via macro, e.g. when we define
a hard upper limit for max number of tracepoint args anyway, so this gets automatically
adjusted as well. Maybe some of the logic from BPF_CALL_*() macros could be borrowed
for this purpose.


I've thought about it, but couldn't figure out how to do it.
Suggestions are welcome.
The preprocessor cannot expand a constant N into N statements.
There gotta be something like:
...
#define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y)
#define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y)
for whatever maximum we will pick.


Right.


I picked 6 as a good compromise and used it twice in bpf_trace_run1x()
Similar thing possible for u64 arg1, u64 arg2, ...
but it will be harder to read.
Looking forward what you can come up with.


Just took a quick look, so the below one would work for generating the
signature and function. I did till 9 here:

#define UNPACK(...)			__VA_ARGS__
#define REPEAT_1(FN, DL, X, ...)	FN(X)
#define REPEAT_2(FN, DL, X, ...)	FN(X) UNPACK DL REPEAT_1(FN, DL, __VA_ARGS__)
#define REPEAT_3(FN, DL, X, ...)	FN(X) UNPACK DL REPEAT_2(FN, DL, __VA_ARGS__)
#define REPEAT_4(FN, DL, X, ...)	FN(X) UNPACK DL REPEAT_3(FN, DL, __VA_ARGS__)
#define REPEAT_5(FN, DL, X, ...)	FN(X) UNPACK DL REPEAT_4(FN, DL, __VA_ARGS__)
#define REPEAT_6(FN, DL, X, ...)	FN(X) UNPACK DL REPEAT_5(FN, DL, __VA_ARGS__)
#define REPEAT_7(FN, DL, X, ...)	FN(X) UNPACK DL REPEAT_6(FN, DL, __VA_ARGS__)
#define REPEAT_8(FN, DL, X, ...)	FN(X) UNPACK DL REPEAT_7(FN, DL, __VA_ARGS__)
#define REPEAT_9(FN, DL, X, ...)	FN(X) UNPACK DL REPEAT_8(FN, DL, __VA_ARGS__)
#define REPEAT(X, FN, DL, ...)		REPEAT_##X(FN, DL, __VA_ARGS__)

#define SARG(X)		u64 arg##X
#define COPY(X)		args[X] = arg##X

#define __DL_COM	(,)
#define __DL_SEM	(;)

#define __SEQ		0, 1, 2, 3, 4, 5, 6, 7, 8, 9

#define BPF_TRACE_DECL_x(x)						\
	void bpf_trace_run##x(struct bpf_prog *prog,			\
			      REPEAT(x, SARG, __DL_COM, __SEQ))
#define BPF_TRACE_DEFN_x(x)						\
	void bpf_trace_run##x(struct bpf_prog *prog,			\
			      REPEAT(x, SARG, __DL_COM, __SEQ))		\
	{								\
		u64 args[x];						\
		REPEAT(x, COPY, __DL_SEM, __SEQ);			\
		__bpf_trace_run(prog, args);				\
	}								\
	EXPORT_SYMBOL_GPL(bpf_trace_run##x)

So doing a ...

BPF_TRACE_DECL_x(5);
BPF_TRACE_DEFN_x(5);


interestingly that in addition to above defining
#define __REPEAT(X, FN, DL, ...) REPEAT_##X(FN, DL, __VA_ARGS__)
to allow recursive expansion and doing
__REPEAT(12, BPF_TRACE_DECL_x, __DL_SEM, __SEQ_1_12);
almost works...
I'm guessing it's hitting preprocessor internal limit on
number of expressions to expand.
It expands 1-6 nicely and 7-12 are partially expanded :)
I guess I have to use
BPF_TRACE_DECL_x(1);
BPF_TRACE_DECL_x(2);
BPF_TRACE_DECL_x(3);
BPF_TRACE_DECL_x(4);
...
BPF_TRACE_DECL_x(12);
which doesn't look better than open coding them.
Only for BPF_TRACE_DEFN_x it's probably worth it.


... will generate in kernel/trace/bpf_trace.i:

void bpf_foo_trace_run5(struct bpf_prog *prog, u64 arg0 , u64 arg1 , u64 arg2 , u64 arg3 , u64 arg4);
void bpf_foo_trace_run5(struct bpf_prog *prog, u64 arg0 , u64 arg1 , u64 arg2 , u64 arg3 , u64 arg4)
{
	u64 args[5];
	args[0] = arg0 ;
	args[1] = arg1 ;
	args[2] = arg2 ;
	args[3] = arg3 ;
	args[4] = arg4;
	__bpf_trace_run(prog, args);
} [...]

Meaning, the EVALx() macros could be removed from there, too. Potentially, the
REPEAT() macro could sit in its own include/linux/ header for others to reuse
or such.


feels too specific for this use case. I'd wait second user before
moving to include/linux/kernel.h

--
To unsubscribe from this list: send the line "unsubscribe linux-api" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
[Index of Archives]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux