Commit 27ed9353 authored by Yonghong Song's avatar Yonghong Song Committed by Alexei Starovoitov
Browse files

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: default avatarYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220831152657.2078805-1-yhs@fb.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent a9c5ad31

include/uapi/linux/bpf.h

+5 −4
Original line number Diff line number Diff line
@@ -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

tools/include/uapi/linux/bpf.h

+5 −4
Original line number Diff line number Diff line
@@ -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