bpf: Update descriptions for helpers bpf_get_func_arg[_cnt]()

Now instead of the number of arguments, the number of registers
holding argument values are stored in trampoline. Update
the description of bpf_get_func_arg[_cnt]() helpers. Previous
programs without struct arguments should continue to work
as usual.

Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220831152657.2078805-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 793103b..3df78c5 100644 (file)
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -5079,12 +5079,12 @@ union bpf_attr {
  *
  * long bpf_get_func_arg(void *ctx, u32 n, u64 *value)
  *     Description
- *             Get **n**-th argument (zero based) of the traced function (for tracing programs)
+ *             Get **n**-th argument register (zero based) of the traced function (for tracing programs)
  *             returned in **value**.
  *
  *     Return
  *             0 on success.
- *             **-EINVAL** if n >= arguments count of traced function.
+ *             **-EINVAL** if n >= argument register count of traced function.
  *
  * long bpf_get_func_ret(void *ctx, u64 *value)
  *     Description
@@ -5097,10 +5097,11 @@ union bpf_attr {
  *
  * long bpf_get_func_arg_cnt(void *ctx)
  *     Description
- *             Get number of arguments of the traced function (for tracing programs).
+ *             Get number of registers of the traced function (for tracing programs) where
+ *             function arguments are stored in these registers.
  *
  *     Return
- *             The number of arguments of the traced function.
+ *             The number of argument registers of the traced function.
  *
  * int bpf_get_retval(void)
  *     Description

diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 793103b..3df78c5 100644 (file)
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -5079,12 +5079,12 @@ union bpf_attr {
  *
  * long bpf_get_func_arg(void *ctx, u32 n, u64 *value)
  *     Description
- *             Get **n**-th argument (zero based) of the traced function (for tracing programs)
+ *             Get **n**-th argument register (zero based) of the traced function (for tracing programs)
  *             returned in **value**.
  *
  *     Return
  *             0 on success.
- *             **-EINVAL** if n >= arguments count of traced function.
+ *             **-EINVAL** if n >= argument register count of traced function.
  *
  * long bpf_get_func_ret(void *ctx, u64 *value)
  *     Description
@@ -5097,10 +5097,11 @@ union bpf_attr {
  *
  * long bpf_get_func_arg_cnt(void *ctx)
  *     Description
- *             Get number of arguments of the traced function (for tracing programs).
+ *             Get number of registers of the traced function (for tracing programs) where
+ *             function arguments are stored in these registers.
  *
  *     Return
- *             The number of arguments of the traced function.
+ *             The number of argument registers of the traced function.
  *
  * int bpf_get_retval(void)
  *     Description