Messages in this thread Patch in this message | | | Date | Mon, 14 Dec 2015 12:39:40 +0800 | From | "Wangnan (F)" <> | Subject | Re: [PATCH v4 09/16] perf tools: Enable indices setting syntax for BPF maps |
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On 2015/12/14 12:28, Alexei Starovoitov wrote: > On Mon, Dec 14, 2015 at 11:27:36AM +0800, Wangnan (F) wrote: >> >> On 2015/12/12 2:21, Alexei Starovoitov wrote: >>> On Fri, Dec 11, 2015 at 08:39:35PM +0800, pi3orama wrote: >>>>> static u64 (*bpf_ktime_get_ns)(void) = >>>>> (void *)5; >>>>> static int (*bpf_trace_printk)(const char *fmt, int fmt_size, ...) = >>>>> (void *)6; >>>>> static int (*bpf_get_smp_processor_id)(void) = >>>>> (void *)8; >>>>> static int (*bpf_perf_event_output)(void *, struct bpf_map_def *, int, >>>>> void *, unsigned long) = >>>>> (void *)23; >>>>> >>>>> Where can I get this magical mistery table? Could this be hidden away in >>>>> some .h file automagically included in bpf scriptlets so that n00bies >>>>> like me don't have to be wtf'ing? >>>>> >>>> They are function numbers defined in bpf.h and bpf-common.h, but they are Linux >>>> headers. Directly include them causes many error for llvm. Also, the function >>>> prototypes are BPF specific and can't included in Linux source. We should have >>>> a place holds those indices and prototypes together. >>> wait, what kind of errors? >>> they are in uapi, so gets installed into /usr/include eventually >>> and I haven't seen any erros either with gcc or clang. >>> >> Sorry. I saw error because I use >> >> #include <linux/bpf.h> >> >> It is okay if I use >> >> #include <uapi/linux/bpf.h> > then let's use that instead of copy-paste. thanks
And what do you think about the BPF function prototype? Should we put them into kernel headers? What about::
diff --git a/include/uapi/linux/bpf_functions.h b/include/uapi/linux/bpf_functions.h new file mode 100644 index 0000000..3a562d4 --- /dev/null +++ b/include/uapi/linux/bpf_functions.h @@ -0,0 +1,2 @@ +DEFINE_BPF_FUNC(void *, map_lookup_elem, void *, void *) +DEFINE_BPF_FUNC(int, map_update_elem, void *, void *, void *, int) [SNIP] diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 9ea2d22..2f2f05f 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -133,143 +133,23 @@ union bpf_attr { }; } __attribute__((aligned(8)));
+#define DEFINE_BPF_FUNC(rettype, name, arglist...) BPF_FUNC_##name + +enum bpf_func_id { +BPF_FUNC_unspec, +#include "bpf_functions.h" +__BPF_FUNC_MAX_ID, +}; + +#ifdef __BPF_SOURCE__ +#undef DEFINE_BPF_FUNC +#define DEFINE_BPF_FUNC(rettype, name, arglist...) static rettype (*name)(arglist) = (void *)BPF_FUNC_##name +#include "bpf_functions.h" +#endif /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call */ enum bpf_func_id { - BPF_FUNC_unspec, [SNIP]
And when compiling BPF source file we add a __BPF_SOURCE__ directive?
Thank you.
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