| Message ID | 20210821025837.1614098-4-davemarchevsky@fb.com |
|---|---|
| State | New |
| Headers | show |
| Series | None | expand |
On Fri, Aug 20, 2021 at 7:59 PM Dave Marchevsky <davemarchevsky@fb.com> wrote: > > bpf_vprintk functions similarly to BPF_SEQ_PRINTF and BPF_SNPRINTF > macros elsewhere in the file - it allows use of bpf_trace_vprintk > without manual conversion of varargs to u64 array. > > Like the bpf_printk macro, bpf_vprintk is meant to be the main interface > to the bpf_trace_vprintk helper and thus is uncapitalized. > > Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com> > --- > tools/lib/bpf/bpf_helpers.h | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h > index b9987c3efa3c..43c8115956c3 100644 > --- a/tools/lib/bpf/bpf_helpers.h > +++ b/tools/lib/bpf/bpf_helpers.h > @@ -224,4 +224,22 @@ enum libbpf_tristate { > ___param, sizeof(___param)); \ > }) > > +/* > + * bpf_vprintk wraps the bpf_trace_printk helper with variadic arguments > + * instead of an array of u64. > + */ > +#define bpf_vprintk(fmt, args...) \ Given BPF_SNPRINTF and BPF_SEQ_PRINTF, should we call this one in all-caps as well? > +({ \ > + static const char ___fmt[] = fmt; \ > + unsigned long long ___param[___bpf_narg(args)]; \ I wonder how hard would it be to still use bpf_trace_printk() if the number of input arguments is less than 3? That way you could use BPF_PRINTF() everywhere, even on old kernels (you just need to remember to use < 3 arguments). WDYT? It might be more challenging than it seems, given it's hard to do conditionals inside #defines :( > + \ > + _Pragma("GCC diagnostic push") \ > + _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \ > + ___bpf_fill(___param, args); \ > + _Pragma("GCC diagnostic pop") \ > + \ > + bpf_trace_vprintk(___fmt, sizeof(___fmt), \ > + ___param, sizeof(___param)); \ > +}) > + > #endif > -- > 2.30.2 >
diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h index b9987c3efa3c..43c8115956c3 100644 --- a/tools/lib/bpf/bpf_helpers.h +++ b/tools/lib/bpf/bpf_helpers.h @@ -224,4 +224,22 @@ enum libbpf_tristate { ___param, sizeof(___param)); \ }) +/* + * bpf_vprintk wraps the bpf_trace_printk helper with variadic arguments + * instead of an array of u64. + */ +#define bpf_vprintk(fmt, args...) \ +({ \ + static const char ___fmt[] = fmt; \ + unsigned long long ___param[___bpf_narg(args)]; \ + \ + _Pragma("GCC diagnostic push") \ + _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \ + ___bpf_fill(___param, args); \ + _Pragma("GCC diagnostic pop") \ + \ + bpf_trace_vprintk(___fmt, sizeof(___fmt), \ + ___param, sizeof(___param)); \ +}) + #endif
bpf_vprintk functions similarly to BPF_SEQ_PRINTF and BPF_SNPRINTF macros elsewhere in the file - it allows use of bpf_trace_vprintk without manual conversion of varargs to u64 array. Like the bpf_printk macro, bpf_vprintk is meant to be the main interface to the bpf_trace_vprintk helper and thus is uncapitalized. Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com> --- tools/lib/bpf/bpf_helpers.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)