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authorAlexei Starovoitov <ast@plumgrid.com>2015-05-19 16:59:05 -0700
committerDavid S. Miller <davem@davemloft.net>2015-05-21 17:07:59 -0400
commit5bacd7805ab4f07a69c7ef4b1d45ce553d2b1c3a (patch)
tree6e2b12a280e4431e2a5c3d971a8d3ebad4c0b5bc /samples/bpf/Makefile
parentb52f00e6a7154308a08d0a2edab621f277801a2c (diff)
downloadlinux-5bacd7805ab4f07a69c7ef4b1d45ce553d2b1c3a.tar.bz2
samples/bpf: bpf_tail_call example for tracing
kprobe example that demonstrates how future seccomp programs may look like. It attaches to seccomp_phase1() function and tail-calls other BPF programs depending on syscall number. Existing optimized classic BPF seccomp programs generated by Chrome look like: if (sd.nr < 121) { if (sd.nr < 57) { if (sd.nr < 22) { if (sd.nr < 7) { if (sd.nr < 4) { if (sd.nr < 1) { check sys_read } else { if (sd.nr < 3) { check sys_write and sys_open } else { check sys_close } } } else { } else { } else { } else { } else { } the future seccomp using native eBPF may look like: bpf_tail_call(&sd, &syscall_jmp_table, sd.nr); which is simpler, faster and leaves more room for per-syscall checks. Usage: $ sudo ./tracex5 <...>-366 [001] d... 4.870033: : read(fd=1, buf=00007f6d5bebf000, size=771) <...>-369 [003] d... 4.870066: : mmap <...>-369 [003] d... 4.870077: : syscall=110 (one of get/set uid/pid/gid) <...>-369 [003] d... 4.870089: : syscall=107 (one of get/set uid/pid/gid) sh-369 [000] d... 4.891740: : read(fd=0, buf=00000000023d1000, size=512) sh-369 [000] d... 4.891747: : write(fd=1, buf=00000000023d3000, size=512) sh-369 [000] d... 4.891747: : read(fd=1, buf=00000000023d3000, size=512) Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'samples/bpf/Makefile')
-rw-r--r--samples/bpf/Makefile4
1 files changed, 4 insertions, 0 deletions
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 8fdbd73429dd..ded10d05617e 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -10,6 +10,7 @@ hostprogs-y += tracex1
hostprogs-y += tracex2
hostprogs-y += tracex3
hostprogs-y += tracex4
+hostprogs-y += tracex5
test_verifier-objs := test_verifier.o libbpf.o
test_maps-objs := test_maps.o libbpf.o
@@ -20,6 +21,7 @@ tracex1-objs := bpf_load.o libbpf.o tracex1_user.o
tracex2-objs := bpf_load.o libbpf.o tracex2_user.o
tracex3-objs := bpf_load.o libbpf.o tracex3_user.o
tracex4-objs := bpf_load.o libbpf.o tracex4_user.o
+tracex5-objs := bpf_load.o libbpf.o tracex5_user.o
# Tell kbuild to always build the programs
always := $(hostprogs-y)
@@ -29,6 +31,7 @@ always += tracex1_kern.o
always += tracex2_kern.o
always += tracex3_kern.o
always += tracex4_kern.o
+always += tracex5_kern.o
always += tcbpf1_kern.o
HOSTCFLAGS += -I$(objtree)/usr/include
@@ -40,6 +43,7 @@ HOSTLOADLIBES_tracex1 += -lelf
HOSTLOADLIBES_tracex2 += -lelf
HOSTLOADLIBES_tracex3 += -lelf
HOSTLOADLIBES_tracex4 += -lelf -lrt
+HOSTLOADLIBES_tracex5 += -lelf
# point this to your LLVM backend with bpf support
LLC=$(srctree)/tools/bpf/llvm/bld/Debug+Asserts/bin/llc