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authorJosef Bacik <jbacik@fb.com>2017-11-07 21:28:43 +0100
committerDavid S. Miller <davem@davemloft.net>2017-11-11 04:18:06 +0100
commiteafb3401faf243f7dca0e23325242cb8c2269ee9 (patch)
treed7dffdccd2bb46bd11e8fffef50c3690b244c64c /tools
parentbpf: add a bpf_override_function helper (diff)
downloadlinux-eafb3401faf243f7dca0e23325242cb8c2269ee9.tar.xz
linux-eafb3401faf243f7dca0e23325242cb8c2269ee9.zip
samples/bpf: add a test for bpf_override_return
This adds a basic test for bpf_override_return to verify it works. We override the main function for mounting a btrfs fs so it'll return -ENOMEM and then make sure that trying to mount a btrfs fs will fail. Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Josef Bacik <jbacik@fb.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'tools')
-rw-r--r--tools/include/uapi/linux/bpf.h7
-rw-r--r--tools/testing/selftests/bpf/bpf_helpers.h3
2 files changed, 8 insertions, 2 deletions
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index e880ae6434ee..adb66f78b674 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -677,6 +677,10 @@ union bpf_attr {
* @buf: buf to fill
* @buf_size: size of the buf
* Return : 0 on success or negative error code
+ *
+ * int bpf_override_return(pt_regs, rc)
+ * @pt_regs: pointer to struct pt_regs
+ * @rc: the return value to set
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -736,7 +740,8 @@ union bpf_attr {
FN(xdp_adjust_meta), \
FN(perf_event_read_value), \
FN(perf_prog_read_value), \
- FN(getsockopt),
+ FN(getsockopt), \
+ FN(override_return),
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
* function eBPF program intends to call
diff --git a/tools/testing/selftests/bpf/bpf_helpers.h b/tools/testing/selftests/bpf/bpf_helpers.h
index fd9a17fa8a8b..33cb00e46c49 100644
--- a/tools/testing/selftests/bpf/bpf_helpers.h
+++ b/tools/testing/selftests/bpf/bpf_helpers.h
@@ -82,7 +82,8 @@ static int (*bpf_perf_event_read_value)(void *map, unsigned long long flags,
static int (*bpf_perf_prog_read_value)(void *ctx, void *buf,
unsigned int buf_size) =
(void *) BPF_FUNC_perf_prog_read_value;
-
+static int (*bpf_override_return)(void *ctx, unsigned long rc) =
+ (void *) BPF_FUNC_override_return;
/* llvm builtin functions that eBPF C program may use to
* emit BPF_LD_ABS and BPF_LD_IND instructions