bpf: Resolve BTF IDs in vmlinux image

Using BTF_ID_LIST macro to define lists for several helpers
using BTF arguments.

And running resolve_btfids on vmlinux elf object during linking,
so the .BTF_ids section gets the IDs resolved.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200711215329.41165-5-jolsa@kernel.org

diff --git a/Makefile b/Makefile
index 017e775..462f1a7 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -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

diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
index a6c361e..48d8e73 100644 (file)
--- a/kernel/bpf/stackmap.c
+++ b/kernel/bpf/stackmap.c
@@ -9,6 +9,7 @@
 #include <linux/elf.h>
 #include <linux/pagemap.h>
 #include <linux/irq_work.h>
+#include <linux/btf_ids.h>
 #include "percpu_freelist.h"
 
 #define STACK_CREATE_FLAG_MASK                                 \
@@ -576,7 +577,9 @@ BPF_CALL_4(bpf_get_task_stack, struct task_struct *, task, void *, buf,
        return __bpf_get_stack(regs, task, buf, size, flags);
 }
 
-static int bpf_get_task_stack_btf_ids[5];
+BTF_ID_LIST(bpf_get_task_stack_btf_ids)
+BTF_ID(struct, task_struct)
+
 const struct bpf_func_proto bpf_get_task_stack_proto = {
        .func           = bpf_get_task_stack,
        .gpl_only       = false,

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index e0b7775..e178e8e 100644 (file)
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -13,6 +13,7 @@
 #include <linux/kprobes.h>
 #include <linux/syscalls.h>
 #include <linux/error-injection.h>
+#include <linux/btf_ids.h>
 
 #include <asm/tlb.h>
 
@@ -710,7 +711,9 @@ out:
        return err;
 }
 
-static int bpf_seq_printf_btf_ids[5];
+BTF_ID_LIST(bpf_seq_printf_btf_ids)
+BTF_ID(struct, seq_file)
+
 static const struct bpf_func_proto bpf_seq_printf_proto = {
        .func           = bpf_seq_printf,
        .gpl_only       = true,
@@ -728,7 +731,9 @@ BPF_CALL_3(bpf_seq_write, struct seq_file *, m, const void *, data, u32, len)
        return seq_write(m, data, len) ? -EOVERFLOW : 0;
 }
 
-static int bpf_seq_write_btf_ids[5];
+BTF_ID_LIST(bpf_seq_write_btf_ids)
+BTF_ID(struct, seq_file)
+
 static const struct bpf_func_proto bpf_seq_write_proto = {
        .func           = bpf_seq_write,
        .gpl_only       = true,

diff --git a/net/core/filter.c b/net/core/filter.c
index ddcc0d6..4e57244 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -75,6 +75,7 @@
 #include <net/ipv6_stubs.h>
 #include <net/bpf_sk_storage.h>
 #include <net/transp_v6.h>
+#include <linux/btf_ids.h>
 
 /**
  *     sk_filter_trim_cap - run a packet through a socket filter
@@ -3779,7 +3780,9 @@ static const struct bpf_func_proto bpf_skb_event_output_proto = {
        .arg5_type      = ARG_CONST_SIZE_OR_ZERO,
 };
 
-static int bpf_skb_output_btf_ids[5];
+BTF_ID_LIST(bpf_skb_output_btf_ids)
+BTF_ID(struct, sk_buff)
+
 const struct bpf_func_proto bpf_skb_output_proto = {
        .func           = bpf_skb_event_output,
        .gpl_only       = true,
@@ -4173,7 +4176,9 @@ static const struct bpf_func_proto bpf_xdp_event_output_proto = {
        .arg5_type      = ARG_CONST_SIZE_OR_ZERO,
 };
 
-static int bpf_xdp_output_btf_ids[5];
+BTF_ID_LIST(bpf_xdp_output_btf_ids)
+BTF_ID(struct, xdp_buff)
+
 const struct bpf_func_proto bpf_xdp_output_proto = {
        .func           = bpf_xdp_event_output,
        .gpl_only       = true,

diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 92dd745..e26f02d 100755 (executable)
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -336,6 +336,12 @@ fi
 
 vmlinux_link vmlinux "${kallsymso}" ${btf_vmlinux_bin_o}
 
+# fill in BTF IDs
+if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then
+info BTFIDS vmlinux
+${RESOLVE_BTFIDS} vmlinux
+fi
+
 if [ -n "${CONFIG_BUILDTIME_TABLE_SORT}" ]; then
        info SORTTAB vmlinux
        if ! sorttable vmlinux; then