[PATCHv3 bpf-next 1/2] bpf: Check CONFIG_BPF option for resolve_btfids

Currently all the resolve_btfids 'users' are under CONFIG_BPF
code, so if we have CONFIG_BPF disabled, resolve_btfids will
fail, because there's no data to resolve.

Disabling resolve_btfids if there's CONFIG_BPF disabled,
so we won't fail such builds.

Suggested-by: Andrii Nakryiko <redacted>
Acked-by: Andrii Nakryiko <redacted>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
v3 changes:
  - updated subject, added ack

 Makefile                | 4 +++-
 scripts/link-vmlinux.sh | 6 +++---
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/Makefile b/Makefile
index c4470a4e131f..b05682eea2c0 100644
--- a/Makefile
+++ b/Makefile

@@ -1084,13 +1084,15 @@ ifdef CONFIG_STACK_VALIDATION
   endif
 endif
 
+ifdef CONFIG_BPF
 ifdef CONFIG_DEBUG_INFO_BTF
   ifeq ($(has_libelf),1)
     resolve_btfids_target := tools/bpf/resolve_btfids FORCE
   else
     ERROR_RESOLVE_BTFIDS := 1
   endif
-endif
+endif # CONFIG_DEBUG_INFO_BTF
+endif # CONFIG_BPF
 
 PHONY += prepare0
 

diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index e6e2d9e5ff48..dbde59d343b1 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh

@@ -341,9 +341,9 @@ 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
+if [ -n "${CONFIG_DEBUG_INFO_BTF}" -a -n "${CONFIG_BPF}" ]; then
+	info BTFIDS vmlinux
+	${RESOLVE_BTFIDS} vmlinux
 fi
 
 if [ -n "${CONFIG_BUILDTIME_TABLE_SORT}" ]; then

-- 
2.26.2

Seth reported problem with cross builds, that fail
on resolve_btfids build, because we are trying to
build it on cross build arch.

Fixing this by always forcing the host arch.

Reported-by: Seth Forshee <redacted>
Acked-by: Andrii Nakryiko <redacted>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 tools/bpf/resolve_btfids/Makefile | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/bpf/resolve_btfids/Makefile b/tools/bpf/resolve_btfids/Makefile
index a88cd4426398..d3c818b8d8d3 100644
--- a/tools/bpf/resolve_btfids/Makefile
+++ b/tools/bpf/resolve_btfids/Makefile

@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0-only
 include ../../scripts/Makefile.include
+include ../../scripts/Makefile.arch
 
 ifeq ($(srctree),)
 srctree := $(patsubst %/,%,$(dir $(CURDIR)))

@@ -29,6 +30,7 @@ endif
 AR       = $(HOSTAR)
 CC       = $(HOSTCC)
 LD       = $(HOSTLD)
+ARCH     = $(HOSTARCH)
 
 OUTPUT ?= $(srctree)/tools/bpf/resolve_btfids/
 

-- 
2.26.2

On Wed, Sep 23, 2020 at 08:57:34PM +0200, Jiri Olsa wrote:

Currently all the resolve_btfids 'users' are under CONFIG_BPF
code, so if we have CONFIG_BPF disabled, resolve_btfids will
fail, because there's no data to resolve.

Disabling resolve_btfids if there's CONFIG_BPF disabled,
so we won't fail such builds.

Suggested-by: Andrii Nakryiko <redacted>
Acked-by: Andrii Nakryiko <redacted>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
v3 changes:
  - updated subject, added ack

Applied. Thanks