Commit 07dd1b7e authored by David S. Miller's avatar David S. Miller
Browse files

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 



Alexei Starovoitov says:

====================
pull-request: bpf-next 2020-07-13

The following pull-request contains BPF updates for your *net-next* tree.

We've added 36 non-merge commits during the last 7 day(s) which contain
a total of 62 files changed, 2242 insertions(+), 468 deletions(-).

The main changes are:

1) Avoid trace_printk warning banner by switching bpf_trace_printk to use
   its own tracing event, from Alan.

2) Better libbpf support on older kernels, from Andrii.

3) Additional AF_XDP stats, from Ciara.

4) build time resolution of BTF IDs, from Jiri.

5) BPF_CGROUP_INET_SOCK_RELEASE hook, from Stanislav.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents bfe4c403 8afb259a

Documentation/bpf/btf.rst

+36 −0
Original line number Diff line number Diff line
@@ -691,6 +691,42 @@ kernel API, the ``insn_off`` is the instruction offset in the unit of ``struct 
bpf_insn``. For ELF API, the ``insn_off`` is the byte offset from the

beginning of section (``btf_ext_info_sec->sec_name_off``).



4.2 .BTF_ids section

====================



The .BTF_ids section encodes BTF ID values that are used within the kernel.



This section is created during the kernel compilation with the help of

macros defined in ``include/linux/btf_ids.h`` header file. Kernel code can

use them to create lists and sets (sorted lists) of BTF ID values.



The ``BTF_ID_LIST`` and ``BTF_ID`` macros define unsorted list of BTF ID values,

with following syntax::



  BTF_ID_LIST(list)

  BTF_ID(type1, name1)

  BTF_ID(type2, name2)



resulting in following layout in .BTF_ids section::



  __BTF_ID__type1__name1__1:

  .zero 4

  __BTF_ID__type2__name2__2:

  .zero 4



The ``u32 list[];`` variable is defined to access the list.



The ``BTF_ID_UNUSED`` macro defines 4 zero bytes. It's used when we

want to define unused entry in BTF_ID_LIST, like::



      BTF_ID_LIST(bpf_skb_output_btf_ids)

      BTF_ID(struct, sk_buff)

      BTF_ID_UNUSED

      BTF_ID(struct, task_struct)



All the BTF ID lists and sets are compiled in the .BTF_ids section and

resolved during the linking phase of kernel build by ``resolve_btfids`` tool.



5. Using BTF

************

Makefile

+20 −5
Original line number Diff line number Diff line
@@ -448,6 +448,7 @@ OBJSIZE = $(CROSS_COMPILE)size 
STRIP		= $(CROSS_COMPILE)strip

endif

PAHOLE		= pahole

RESOLVE_BTFIDS	= $(objtree)/tools/bpf/resolve_btfids/resolve_btfids

LEX		= flex

YACC		= bison

AWK		= awk
@@ -510,7 +511,7 @@ GCC_PLUGINS_CFLAGS := 
CLANG_FLAGS :=



export ARCH SRCARCH CONFIG_SHELL BASH HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE LD CC

export CPP AR NM STRIP OBJCOPY OBJDUMP OBJSIZE READELF PAHOLE LEX YACC AWK INSTALLKERNEL

export CPP AR NM STRIP OBJCOPY OBJDUMP OBJSIZE READELF PAHOLE RESOLVE_BTFIDS LEX YACC AWK INSTALLKERNEL

export PERL PYTHON PYTHON3 CHECK CHECKFLAGS MAKE UTS_MACHINE HOSTCXX

export KGZIP KBZIP2 KLZOP LZMA LZ4 XZ

export KBUILD_HOSTCXXFLAGS KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS LDFLAGS_MODULE
@@ -1053,9 +1054,10 @@ export mod_sign_cmd 


HOST_LIBELF_LIBS = $(shell pkg-config libelf --libs 2>/dev/null || echo -lelf)



ifdef CONFIG_STACK_VALIDATION

  has_libelf := $(call try-run,\

has_libelf = $(call try-run,\

               echo "int main() {}" | $(HOSTCC) -xc -o /dev/null $(HOST_LIBELF_LIBS) -,1,0)



ifdef CONFIG_STACK_VALIDATION

  ifeq ($(has_libelf),1)

    objtool_target := tools/objtool FORCE

  else
@@ -1064,6 +1066,14 @@ ifdef CONFIG_STACK_VALIDATION 
  endif

endif



ifdef CONFIG_DEBUG_INFO_BTF

  ifeq ($(has_libelf),1)

    resolve_btfids_target := tools/bpf/resolve_btfids FORCE

  else

    ERROR_RESOLVE_BTFIDS := 1

  endif

endif



PHONY += prepare0



export MODORDER := $(extmod-prefix)modules.order
@@ -1175,7 +1185,7 @@ prepare0: archprepare 
	$(Q)$(MAKE) $(build)=.



# All the preparing..

prepare: prepare0 prepare-objtool

prepare: prepare0 prepare-objtool prepare-resolve_btfids



# Support for using generic headers in asm-generic

asm-generic := -f $(srctree)/scripts/Makefile.asm-generic obj
@@ -1188,7 +1198,7 @@ uapi-asm-generic: 
	$(Q)$(MAKE) $(asm-generic)=arch/$(SRCARCH)/include/generated/uapi/asm \

	generic=include/uapi/asm-generic



PHONY += prepare-objtool

PHONY += prepare-objtool prepare-resolve_btfids

prepare-objtool: $(objtool_target)

ifeq ($(SKIP_STACK_VALIDATION),1)

ifdef CONFIG_UNWINDER_ORC
@@ -1199,6 +1209,11 @@ else 
endif

endif



prepare-resolve_btfids: $(resolve_btfids_target)

ifeq ($(ERROR_RESOLVE_BTFIDS),1)

	@echo "error: Cannot resolve BTF IDs for CONFIG_DEBUG_INFO_BTF, please install libelf-dev, libelf-devel or elfutils-libelf-devel" >&2

	@false

endif

# Generate some files

# ---------------------------------------------------------------------------

include/asm-generic/vmlinux.lds.h

+4 −0
Original line number Diff line number Diff line
@@ -641,6 +641,10 @@ 
		__start_BTF = .;					\

		*(.BTF)							\

		__stop_BTF = .;						\

	}								\

	. = ALIGN(4);							\

	.BTF_ids : AT(ADDR(.BTF_ids) - LOAD_OFFSET) {			\

		*(.BTF_ids)						\

	}

#else

#define BTF

include/linux/bpf-cgroup.h

+4 −0
Original line number Diff line number Diff line
@@ -210,6 +210,9 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *map, void *key, 
#define BPF_CGROUP_RUN_PROG_INET_SOCK(sk)				       \

	BPF_CGROUP_RUN_SK_PROG(sk, BPF_CGROUP_INET_SOCK_CREATE)



#define BPF_CGROUP_RUN_PROG_INET_SOCK_RELEASE(sk)			       \

	BPF_CGROUP_RUN_SK_PROG(sk, BPF_CGROUP_INET_SOCK_RELEASE)



#define BPF_CGROUP_RUN_PROG_INET4_POST_BIND(sk)				       \

	BPF_CGROUP_RUN_SK_PROG(sk, BPF_CGROUP_INET4_POST_BIND)
@@ -401,6 +404,7 @@ static inline int bpf_percpu_cgroup_storage_update(struct bpf_map *map, 
#define BPF_CGROUP_RUN_PROG_INET_INGRESS(sk,skb) ({ 0; })

#define BPF_CGROUP_RUN_PROG_INET_EGRESS(sk,skb) ({ 0; })

#define BPF_CGROUP_RUN_PROG_INET_SOCK(sk) ({ 0; })

#define BPF_CGROUP_RUN_PROG_INET_SOCK_RELEASE(sk) ({ 0; })

#define BPF_CGROUP_RUN_PROG_INET4_BIND(sk, uaddr) ({ 0; })

#define BPF_CGROUP_RUN_PROG_INET6_BIND(sk, uaddr) ({ 0; })

#define BPF_CGROUP_RUN_PROG_INET4_POST_BIND(sk) ({ 0; })

include/linux/btf_ids.h

0 → 100644
+87 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */



#ifndef _LINUX_BTF_IDS_H

#define _LINUX_BTF_IDS_H



#include <linux/compiler.h> /* for __PASTE */



/*

 * Following macros help to define lists of BTF IDs placed

 * in .BTF_ids section. They are initially filled with zeros

 * (during compilation) and resolved later during the

 * linking phase by resolve_btfids tool.

 *

 * Any change in list layout must be reflected in resolve_btfids

 * tool logic.

 */



#define BTF_IDS_SECTION ".BTF_ids"



#define ____BTF_ID(symbol)				\

asm(							\

".pushsection " BTF_IDS_SECTION ",\"a\";       \n"	\

".local " #symbol " ;                          \n"	\

".type  " #symbol ", @object;                  \n"	\

".size  " #symbol ", 4;                        \n"	\

#symbol ":                                     \n"	\

".zero 4                                       \n"	\

".popsection;                                  \n");



#define __BTF_ID(symbol) \

	____BTF_ID(symbol)



#define __ID(prefix) \

	__PASTE(prefix, __COUNTER__)



/*

 * The BTF_ID defines unique symbol for each ID pointing

 * to 4 zero bytes.

 */

#define BTF_ID(prefix, name) \

	__BTF_ID(__ID(__BTF_ID__##prefix##__##name##__))



/*

 * The BTF_ID_LIST macro defines pure (unsorted) list

 * of BTF IDs, with following layout:

 *

 * BTF_ID_LIST(list1)

 * BTF_ID(type1, name1)

 * BTF_ID(type2, name2)

 *

 * list1:

 * __BTF_ID__type1__name1__1:

 * .zero 4

 * __BTF_ID__type2__name2__2:

 * .zero 4

 *

 */

#define __BTF_ID_LIST(name)				\

asm(							\

".pushsection " BTF_IDS_SECTION ",\"a\";       \n"	\

".local " #name ";                             \n"	\

#name ":;                                      \n"	\

".popsection;                                  \n");	\



#define BTF_ID_LIST(name)				\

__BTF_ID_LIST(name)					\

extern u32 name[];



/*

 * The BTF_ID_UNUSED macro defines 4 zero bytes.

 * It's used when we want to define 'unused' entry

 * in BTF_ID_LIST, like:

 *

 *   BTF_ID_LIST(bpf_skb_output_btf_ids)

 *   BTF_ID(struct, sk_buff)

 *   BTF_ID_UNUSED

 *   BTF_ID(struct, task_struct)

 */



#define BTF_ID_UNUSED					\

asm(							\

".pushsection " BTF_IDS_SECTION ",\"a\";       \n"	\

".zero 4                                       \n"	\

".popsection;                                  \n");





#endif

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