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authorYonghong Song <yhs@fb.com>2018-04-28 22:28:12 -0700
committerAlexei Starovoitov <ast@kernel.org>2018-04-29 08:45:53 -0700
commitde2ff05f48afcde816ff4edb217417f62f624ab5 (patch)
treed67117e42ddcdc0da2e91ea8949bc489f0553cef
parent9cbe1f5a32dcd6d0508326f7d9098e5bc380a4fe (diff)
downloadlinux-stericsson-de2ff05f48afcde816ff4edb217417f62f624ab5.tar.gz
tools/bpf: add bpf_get_stack helper to tools headers
The tools header file bpf.h is synced with kernel uapi bpf.h. The new helper is also added to bpf_helpers.h. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
-rw-r--r--tools/include/uapi/linux/bpf.h42
-rw-r--r--tools/testing/selftests/bpf/bpf_helpers.h2
2 files changed, 42 insertions, 2 deletions
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index da77a9388947..1afb606a18b9 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1767,6 +1767,40 @@ union bpf_attr {
* **CONFIG_XFRM** configuration option.
* Return
* 0 on success, or a negative error in case of failure.
+ *
+ * int bpf_get_stack(struct pt_regs *regs, void *buf, u32 size, u64 flags)
+ * Description
+ * Return a user or a kernel stack in bpf program provided buffer.
+ * To achieve this, the helper needs *ctx*, which is a pointer
+ * to the context on which the tracing program is executed.
+ * To store the stacktrace, the bpf program provides *buf* with
+ * a nonnegative *size*.
+ *
+ * The last argument, *flags*, holds the number of stack frames to
+ * skip (from 0 to 255), masked with
+ * **BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
+ * the following flags:
+ *
+ * **BPF_F_USER_STACK**
+ * Collect a user space stack instead of a kernel stack.
+ * **BPF_F_USER_BUILD_ID**
+ * Collect buildid+offset instead of ips for user stack,
+ * only valid if **BPF_F_USER_STACK** is also specified.
+ *
+ * **bpf_get_stack**\ () can collect up to
+ * **PERF_MAX_STACK_DEPTH** both kernel and user frames, subject
+ * to sufficient large buffer size. Note that
+ * this limit can be controlled with the **sysctl** program, and
+ * that it should be manually increased in order to profile long
+ * user stacks (such as stacks for Java programs). To do so, use:
+ *
+ * ::
+ *
+ * # sysctl kernel.perf_event_max_stack=<new value>
+ *
+ * Return
+ * a non-negative value equal to or less than size on success, or
+ * a negative error in case of failure.
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -1835,7 +1869,8 @@ union bpf_attr {
FN(msg_pull_data), \
FN(bind), \
FN(xdp_adjust_tail), \
- FN(skb_get_xfrm_state),
+ FN(skb_get_xfrm_state), \
+ FN(get_stack),
/* integer value in 'imm' field of BPF_CALL instruction selects which helper
* function eBPF program intends to call
@@ -1869,11 +1904,14 @@ enum bpf_func_id {
/* BPF_FUNC_skb_set_tunnel_key and BPF_FUNC_skb_get_tunnel_key flags. */
#define BPF_F_TUNINFO_IPV6 (1ULL << 0)
-/* BPF_FUNC_get_stackid flags. */
+/* flags for both BPF_FUNC_get_stackid and BPF_FUNC_get_stack. */
#define BPF_F_SKIP_FIELD_MASK 0xffULL
#define BPF_F_USER_STACK (1ULL << 8)
+/* flags used by BPF_FUNC_get_stackid only. */
#define BPF_F_FAST_STACK_CMP (1ULL << 9)
#define BPF_F_REUSE_STACKID (1ULL << 10)
+/* flags used by BPF_FUNC_get_stack only. */
+#define BPF_F_USER_BUILD_ID (1ULL << 11)
/* BPF_FUNC_skb_set_tunnel_key flags. */
#define BPF_F_ZERO_CSUM_TX (1ULL << 1)
diff --git a/tools/testing/selftests/bpf/bpf_helpers.h b/tools/testing/selftests/bpf/bpf_helpers.h
index 69d7b918e66a..265f8e0e8ada 100644
--- a/tools/testing/selftests/bpf/bpf_helpers.h
+++ b/tools/testing/selftests/bpf/bpf_helpers.h
@@ -101,6 +101,8 @@ static int (*bpf_xdp_adjust_tail)(void *ctx, int offset) =
static int (*bpf_skb_get_xfrm_state)(void *ctx, int index, void *state,
int size, int flags) =
(void *) BPF_FUNC_skb_get_xfrm_state;
+static int (*bpf_get_stack)(void *ctx, void *buf, int size, int flags) =
+ (void *) BPF_FUNC_get_stack;
/* llvm builtin functions that eBPF C program may use to
* emit BPF_LD_ABS and BPF_LD_IND instructions