linux-toradex.git/samples/bpf/tracex2_kern.c, branch v5.0

bpf, samples: don't zero data when not needed

2016-04-15T01:40:42+00:00

Remove the zero initialization in the sample programs where appropriate.
Note that this is an optimization which is now possible, old programs
still doing the zero initialization are just fine as well. Also, make
sure we don't have padding issues when we don't memset() the entire
struct anymore.

Signed-off-by: Daniel Borkmann 
Acked-by: Alexei Starovoitov 
Signed-off-by: David S. Miller

samples/bpf: Enable powerpc support

2016-04-06T20:01:29+00:00

Add the necessary definitions for building bpf samples on ppc.

Since ppc doesn't store function return address on the stack, modify how
PT_REGS_RET() and PT_REGS_FP() work.

Also, introduce PT_REGS_IP() to access the instruction pointer.

Cc: Alexei Starovoitov 
Cc: Daniel Borkmann 
Cc: David S. Miller 
Cc: Ananth N Mavinakayanahalli 
Cc: Michael Ellerman 
Signed-off-by: Naveen N. Rao 
Acked-by: Alexei Starovoitov 
Signed-off-by: David S. Miller

samples/bpf: update tracex[23] examples to use per-cpu maps

2016-02-06T08:34:36+00:00

Signed-off-by: Alexei Starovoitov 
Signed-off-by: David S. Miller

samples: bpf: enable trace samples for s390x

2015-07-08T22:17:45+00:00

The trace bpf samples do not compile on s390x because they use x86
specific fields from the "pt_regs" structure.

Fix this and access the fields via new PT_REGS macros.

Signed-off-by: Michael Holzheu 
Acked-by: Alexei Starovoitov 
Signed-off-by: David S. Miller

bpf: introduce current->pid, tgid, uid, gid, comm accessors

2015-06-15T22:53:50+00:00

eBPF programs attached to kprobes need to filter based on
current->pid, uid and other fields, so introduce helper functions:

u64 bpf_get_current_pid_tgid(void)
Return: current->tgid << 32 | current->pid

u64 bpf_get_current_uid_gid(void)
Return: current_gid << 32 | current_uid

bpf_get_current_comm(char *buf, int size_of_buf)
stores current->comm into buf

They can be used from the programs attached to TC as well to classify packets
based on current task fields.

Update tracex2 example to print histogram of write syscalls for each process
instead of aggregated for all.

Signed-off-by: Alexei Starovoitov 
Signed-off-by: David S. Miller

samples/bpf: Add counting example for kfree_skb() function calls and the write() syscall

2015-04-02T11:25:50+00:00

this example has two probes in one C file that attach to
different kprove events and use two different maps.

1st probe is x64 specific equivalent of dropmon. It attaches to
kfree_skb, retrevies 'ip' address of kfree_skb() caller and
counts number of packet drops at that 'ip' address. User space
prints 'location - count' map every second.

2nd probe attaches to kprobe:sys_write and computes a histogram
of different write sizes

Usage:
	$ sudo tracex2
	location 0xffffffff81695995 count 1
	location 0xffffffff816d0da9 count 2

	location 0xffffffff81695995 count 2
	location 0xffffffff816d0da9 count 2

	location 0xffffffff81695995 count 3
	location 0xffffffff816d0da9 count 2

	557145+0 records in
	557145+0 records out
	285258240 bytes (285 MB) copied, 1.02379 s, 279 MB/s
		   syscall write() stats
	     byte_size       : count     distribution
	       1 -> 1        : 3        |                                      |
	       2 -> 3        : 0        |                                      |
	       4 -> 7        : 0        |                                      |
	       8 -> 15       : 0        |                                      |
	      16 -> 31       : 2        |                                      |
	      32 -> 63       : 3        |                                      |
	      64 -> 127      : 1        |                                      |
	     128 -> 255      : 1        |                                      |
	     256 -> 511      : 0        |                                      |
	     512 -> 1023     : 1118968  |************************************* |

Ctrl-C at any time. Kernel will auto cleanup maps and programs

	$ addr2line -ape ./bld_x64/vmlinux 0xffffffff81695995
	0xffffffff816d0da9 0xffffffff81695995:
	./bld_x64/../net/ipv4/icmp.c:1038 0xffffffff816d0da9:
	./bld_x64/../net/unix/af_unix.c:1231

Signed-off-by: Alexei Starovoitov 
Cc: Arnaldo Carvalho de Melo 
Cc: Arnaldo Carvalho de Melo 
Cc: Daniel Borkmann 
Cc: David S. Miller 
Cc: Jiri Olsa 
Cc: Linus Torvalds 
Cc: Masami Hiramatsu 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Peter Zijlstra 
Cc: Steven Rostedt 
Link: http://lkml.kernel.org/r/1427312966-8434-8-git-send-email-ast@plumgrid.com
Signed-off-by: Ingo Molnar