tools/testing/selftests/bpf/sdt.h

Source file repositories/reference/linux-study-clean/tools/testing/selftests/bpf/sdt.h

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/bpf/sdt.h
Extension
.h
Size
22515 bytes
Lines
516
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

This file is dedicated to the public domain, pursuant to CC0
   (https://creativecommons.org/publicdomain/zero/1.0/)
*/

#ifndef _SYS_SDT_H
#define _SYS_SDT_H    1

/*
  This file defines a family of macros

       STAP_PROBEn(op1, ..., opn)

  that emit a nop into the instruction stream, and some data into an auxiliary
  note section.  The data in the note section describes the operands, in terms
  of size and location.  Each location is encoded as assembler operand string.
  Consumer tools such as gdb or systemtap insert breakpoints on top of
  the nop, and decode the location operand-strings, like an assembler,
  to find the values being passed.

  The operand strings are selected by the compiler for each operand.
  They are constrained by gcc inline-assembler codes.  The default is:

  #define STAP_SDT_ARG_CONSTRAINT nor

  This is a good default if the operands tend to be integral and
  moderate in number (smaller than number of registers).  In other
  cases, the compiler may report "'asm' requires impossible reload" or
  similar.  In this case, consider simplifying the macro call (fewer
  and simpler operands), reduce optimization, or override the default
  constraints string via:

  #define STAP_SDT_ARG_CONSTRAINT g
  #include <sys/sdt.h>

  See also:
  https://sourceware.org/systemtap/wiki/UserSpaceProbeImplementation
  https://gcc.gnu.org/onlinedocs/gcc/Constraints.html
 */



#ifdef __ASSEMBLER__
# define _SDT_PROBE(provider, name, n, arglist)	\
  _SDT_ASM_BODY(provider, name, _SDT_ASM_SUBSTR_1, (_SDT_DEPAREN_##n arglist)) \
  _SDT_ASM_BASE
# define _SDT_ASM_1(x)			x;
# define _SDT_ASM_2(a, b)		a,b;
# define _SDT_ASM_3(a, b, c)		a,b,c;
# define _SDT_ASM_5(a, b, c, d, e)	a,b,c,d,e;
# define _SDT_ASM_STRING_1(x)		.asciz #x;
# define _SDT_ASM_SUBSTR_1(x)		.ascii #x;
# define _SDT_DEPAREN_0()				/* empty */
# define _SDT_DEPAREN_1(a)				a
# define _SDT_DEPAREN_2(a,b)				a b
# define _SDT_DEPAREN_3(a,b,c)				a b c
# define _SDT_DEPAREN_4(a,b,c,d)			a b c d
# define _SDT_DEPAREN_5(a,b,c,d,e)			a b c d e
# define _SDT_DEPAREN_6(a,b,c,d,e,f)			a b c d e f
# define _SDT_DEPAREN_7(a,b,c,d,e,f,g)			a b c d e f g
# define _SDT_DEPAREN_8(a,b,c,d,e,f,g,h)		a b c d e f g h
# define _SDT_DEPAREN_9(a,b,c,d,e,f,g,h,i)		a b c d e f g h i
# define _SDT_DEPAREN_10(a,b,c,d,e,f,g,h,i,j)		a b c d e f g h i j
# define _SDT_DEPAREN_11(a,b,c,d,e,f,g,h,i,j,k)		a b c d e f g h i j k
# define _SDT_DEPAREN_12(a,b,c,d,e,f,g,h,i,j,k,l)	a b c d e f g h i j k l
#else
#if defined _SDT_HAS_SEMAPHORES
#define _SDT_NOTE_SEMAPHORE_USE(provider, name) \
  __asm__ __volatile__ ("" :: "m" (provider##_##name##_semaphore));
#else
#define _SDT_NOTE_SEMAPHORE_USE(provider, name)
#endif

# define _SDT_PROBE(provider, name, n, arglist) \
  do {									    \
    _SDT_NOTE_SEMAPHORE_USE(provider, name); \
    __asm__ __volatile__ (_SDT_ASM_BODY(provider, name, _SDT_ASM_ARGS, (n)) \
			  :: _SDT_ASM_OPERANDS_##n arglist);		    \
    __asm__ __volatile__ (_SDT_ASM_BASE);				    \
  } while (0)
# define _SDT_S(x)			#x
# define _SDT_ASM_1(x)			_SDT_S(x) "\n"
# define _SDT_ASM_2(a, b)		_SDT_S(a) "," _SDT_S(b) "\n"
# define _SDT_ASM_3(a, b, c)		_SDT_S(a) "," _SDT_S(b) "," \
					_SDT_S(c) "\n"
# define _SDT_ASM_5(a, b, c, d, e)	_SDT_S(a) "," _SDT_S(b) "," \
					_SDT_S(c) "," _SDT_S(d) "," \
					_SDT_S(e) "\n"
# define _SDT_ASM_ARGS(n)		_SDT_ASM_TEMPLATE_##n
# define _SDT_ASM_STRING_1(x)		_SDT_ASM_1(.asciz #x)
# define _SDT_ASM_SUBSTR_1(x)		_SDT_ASM_1(.ascii #x)

Annotation

Implementation Notes