bpf: Generate helpers for pinning through bpf object skeleton

.github/actions/vmtest/action.yml

@@ -0,0 +1,35 @@
+name: 'vmtest'
+description: 'Build + run vmtest'
+inputs:
+  arch:
+    description: 'what arch to test'
+    required: true
+    default: 'x86_64'
+runs:
+  using: "composite"
+  steps:
+    # 1. Setup environment
+    - name: Setup build environment
+      uses: libbpf/ci/setup-build-env@master
+    # 2. Build
+    - name: Build kernel image
+      shell: bash
+      run: ${GITHUB_ACTION_PATH}/build.sh ${{ inputs.arch }}
+    - name: Build selftests
+      shell: bash
+      run: ${GITHUB_ACTION_PATH}/build_selftests.sh
+      env:
+        VMLINUX_BTF: ${{ github.workspace }}/vmlinux
+    # 3. Test
+    - name: Prepare rootfs
+      uses: libbpf/ci/prepare-rootfs@master
+      with:
+        project-name: 'libbpf'
+        arch: ${{ inputs.arch }}
+        kernel-root: '.'
+    - name: Run selftests
+      uses: libbpf/ci/run-qemu@master
+      with:
+        arch: ${{ inputs.arch}}
+        img: '/tmp/root.img'
+        vmlinuz: '${{ github.workspace }}/vmlinuz'

.github/actions/vmtest/build.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+
+set -euo pipefail
+
+ARCH="$1"
+
+THISDIR="$(cd $(dirname $0) && pwd)"
+
+source "${THISDIR}"/helpers.sh
+
+travis_fold start build_kernel "Building kernel"
+
+cp ${GITHUB_WORKSPACE}/travis-ci/vmtest/configs/config-latest.${ARCH} .config
+
+make -j $((4*$(nproc))) olddefconfig all > /dev/null
+
+travis_fold end build_kernel

.github/actions/vmtest/build_selftests.sh

@@ -0,0 +1,42 @@
+#!/bin/bash
+
+set -euo pipefail
+
+THISDIR="$(cd $(dirname $0) && pwd)"
+
+source "${THISDIR}"/helpers.sh
+
+travis_fold start prepare_selftests "Building selftests"
+
+LLVM_VER=15
+LIBBPF_PATH="${REPO_ROOT}"
+
+PREPARE_SELFTESTS_SCRIPT=${THISDIR}/prepare_selftests-${KERNEL}.sh
+if [ -f "${PREPARE_SELFTESTS_SCRIPT}" ]; then
+	(cd "${REPO_ROOT}/${REPO_PATH}/tools/testing/selftests/bpf" && ${PREPARE_SELFTESTS_SCRIPT})
+fi
+
+if [[ "${KERNEL}" = 'LATEST' ]]; then
+	VMLINUX_H=
+else
+	VMLINUX_H=${THISDIR}/vmlinux.h
+fi
+
+cd ${REPO_ROOT}/${REPO_PATH}
+make \
+	CLANG=clang-${LLVM_VER} \
+	LLC=llc-${LLVM_VER} \
+	LLVM_STRIP=llvm-strip-${LLVM_VER} \
+	VMLINUX_BTF="${VMLINUX_BTF}" \
+	VMLINUX_H="${VMLINUX_H}" \
+	-C "${REPO_ROOT}/${REPO_PATH}/tools/testing/selftests/bpf" \
+	-j $((4*$(nproc))) > /dev/null
+cd -
+mkdir "${LIBBPF_PATH}"/selftests
+cp -R "${REPO_ROOT}/${REPO_PATH}/tools/testing/selftests/bpf" \
+	"${LIBBPF_PATH}"/selftests
+cd "${LIBBPF_PATH}"
+rm selftests/bpf/.gitignore
+git add selftests
+
+travis_fold end prepare_selftests

.github/actions/vmtest/helpers.sh

@@ -0,0 +1,44 @@
+# $1 - start or end
+# $2 - fold identifier, no spaces
+# $3 - fold section description
+travis_fold() {
+  local YELLOW='\033[1;33m'
+  local NOCOLOR='\033[0m'
+  if [ -z ${GITHUB_WORKFLOW+x} ]; then
+    echo travis_fold:$1:$2
+    if [ ! -z "${3:-}" ]; then
+      echo -e "${YELLOW}$3${NOCOLOR}"
+    fi
+    echo
+  else
+    if [ $1 = "start" ]; then
+      line="::group::$2"
+      if [ ! -z "${3:-}" ]; then
+        line="$line - ${YELLOW}$3${NOCOLOR}"
+      fi
+    else
+      line="::endgroup::"
+    fi
+    echo -e "$line"
+  fi
+}
+
+__print() {
+  local TITLE=""
+  if [[ -n $2 ]]; then
+      TITLE=" title=$2"
+  fi
+  echo "::$1${TITLE}::$3"
+}
+
+# $1 - title
+# $2 - message
+print_error() {
+  __print error $1 $2
+}
+
+# $1 - title
+# $2 - message
+print_notice() {
+  __print notice $1 $2
+}

.github/workflows/test.yml

@@ -0,0 +1,50 @@
+name: bpf-ci
+
+on:
+  pull_request:
+
+concurrency: 
+  group: ci-test-${{ github.head_ref }}
+  cancel-in-progress: true
+
+jobs:
+  VM_Test:
+    runs-on: ${{ matrix.runs_on }}
+    name: Kernel ${{ matrix.kernel }} on ${{ matrix.runs_on }} + selftests
+    timeout-minutes: 100
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - kernel: 'LATEST'
+            runs_on: ubuntu-latest
+            arch: 'x86_64'
+          - kernel: 'LATEST'
+            runs_on: z15
+            arch: 's390x'
+    env:
+      AUTHOR_EMAIL: "$(git log -1 --pretty=\"%aE\")"
+      KERNEL: LATEST
+      REPO_ROOT: ${{ github.workspace }}
+      REPO_PATH: ""
+    steps:
+      - uses: actions/checkout@v2
+      - if: ${{ github.repository != 'kernel-patches/bpf' && github.repository != 'kernel-patches/bpf-rc' }}
+        name: Download bpf-next tree
+        uses: libbpf/ci/get-linux-source@master
+        with:
+          dest: '.kernel'
+      - if: ${{ github.repository != 'kernel-patches/bpf' && github.repository != 'kernel-patches/bpf-rc' }}
+        name: Move linux source in place
+        shell: bash
+        run: |
+          rm -rf .kernel/.git
+          cp -rf .kernel/. .
+          rm -rf .kernel
+      - uses: libbpf/ci/patch-kernel@master
+        with:
+          patches-root: '${{ github.workspace }}/travis-ci/diffs'
+          repo-root: '${{ github.workspace }}'
+      - uses: ./.github/actions/vmtest
+        with:
+          arch: ${{ matrix.arch }}

README

@@ -1,18 +0,0 @@
-Linux kernel
-============
-
-There are several guides for kernel developers and users. These guides can
-be rendered in a number of formats, like HTML and PDF. Please read
-Documentation/admin-guide/README.rst first.
-
-In order to build the documentation, use ``make htmldocs`` or
-``make pdfdocs``.  The formatted documentation can also be read online at:
-
-    https://www.kernel.org/doc/html/latest/
-
-There are various text files in the Documentation/ subdirectory,
-several of them using the Restructured Text markup notation.
-
-Please read the Documentation/process/changes.rst file, as it contains the
-requirements for building and running the kernel, and information about
-the problems which may result by upgrading your kernel.

tools/bpf/bpftool/gen.c

@@ -1087,6 +1087,8 @@ static int do_skeleton(int argc, char **argv)
 			static inline int load(struct %1$s *skel);	    \n\
 			static inline int attach(struct %1$s *skel);	    \n\
 			static inline void detach(struct %1$s *skel);	    \n\
+			static inline int pin_prog(struct %1$s *skel, const char *path);\n\
+			static inline void unpin_prog(struct %1$s *skel);   \n\
 			static inline void destroy(struct %1$s *skel);	    \n\
 			static inline const void *elf_bytes(size_t *sz);    \n\
 		#endif /* __cplusplus */				    \n\
@@ -1171,7 +1173,19 @@ static int do_skeleton(int argc, char **argv)
 		static inline void					    \n\
 		%1$s__detach(struct %1$s *obj)				    \n\
 		{							    \n\
-			return bpf_object__detach_skeleton(obj->skeleton);  \n\
+			bpf_object__detach_skeleton(obj->skeleton);	    \n\
+		}							    \n\
+									    \n\
+		static inline int					    \n\
+		%1$s__pin_prog(struct %1$s *obj, const char *path)	    \n\
+		{							    \n\
+			return bpf_object__pin_skeleton_prog(obj->skeleton, path);\n\
+		}							    \n\
+									    \n\
+		static inline void					    \n\
+		%1$s__unpin_prog(struct %1$s *obj)			    \n\
+		{							    \n\
+			bpf_object__unpin_skeleton_prog(obj->skeleton);	    \n\
 		}							    \n\
 		",
 		obj_name
@@ -1237,6 +1251,8 @@ static int do_skeleton(int argc, char **argv)
 		int %1$s::load(struct %1$s *skel) { return %1$s__load(skel); }		\n\
 		int %1$s::attach(struct %1$s *skel) { return %1$s__attach(skel); }	\n\
 		void %1$s::detach(struct %1$s *skel) { %1$s__detach(skel); }		\n\
+		int %1$s::pin_prog(struct %1$s *skel, const char *path) { return %1$s__pin_prog(skel, path); }\n\
+		void %1$s::unpin_prog(struct %1$s *skel) { %1$s__unpin_prog(skel); }	\n\
 		void %1$s::destroy(struct %1$s *skel) { %1$s__destroy(skel); }		\n\
 		const void *%1$s::elf_bytes(size_t *sz) { return %1$s__elf_bytes(sz); } \n\
 		#endif /* __cplusplus */				    \n\

tools/lib/bpf/bpf_helpers.h

@@ -137,7 +137,7 @@ struct bpf_map_def {
 
 enum libbpf_pin_type {
 	LIBBPF_PIN_NONE,
-	/* PIN_BY_NAME: pin maps by name (in /sys/fs/bpf by default) */
+	/* PIN_BY_NAME: pin maps by name (in DEFAULT_BPFFS by default) */
 	LIBBPF_PIN_BY_NAME,
 };
 

tools/lib/bpf/libbpf.c

@@ -2180,7 +2180,7 @@ static int build_map_pin_path(struct bpf_map *map, const char *path)
 	int len;
 
 	if (!path)
-		path = "/sys/fs/bpf";
+		path = DEFAULT_BPFFS;
 
 	len = snprintf(buf, PATH_MAX, "%s/%s", path, bpf_map__name(map));
 	if (len < 0)
@@ -12726,6 +12726,65 @@ void bpf_object__detach_skeleton(struct bpf_object_skeleton *s)
 	}
 }
 
+int bpf_object__pin_skeleton_prog(struct bpf_object_skeleton *s,
+				  const char *path)
+{
+	struct bpf_link *link;
+	int err;
+	int i;
+
+	if (!s->prog_cnt)
+		return libbpf_err(-EINVAL);
+
+	if (!path)
+		path = DEFAULT_BPFFS;
+
+	for (i = 0; i < s->prog_cnt; i++) {
+		char buf[PATH_MAX];
+		int len;
+
+		len = snprintf(buf, PATH_MAX, "%s/%s", path, s->progs[i].name);
+		if (len < 0) {
+			err = -EINVAL;
+			goto err_unpin_prog;
+		} else if (len >= PATH_MAX) {
+			err = -ENAMETOOLONG;
+			goto err_unpin_prog;
+		}
+
+		link = *s->progs[i].link;
+		if (!link) {
+			err = -EINVAL;
+			goto err_unpin_prog;
+		}
+
+		err = bpf_link__pin(link, buf);
+		if (err)
+			goto err_unpin_prog;
+	}
+
+	return 0;
+
+err_unpin_prog:
+	bpf_object__unpin_skeleton_prog(s);
+
+	return libbpf_err(err);
+}
+
+void bpf_object__unpin_skeleton_prog(struct bpf_object_skeleton *s)
+{
+	struct bpf_link *link;
+	int i;
+
+	for (i = 0; i < s->prog_cnt; i++) {
+		link = *s->progs[i].link;
+		if (!link || !link->pin_path)
+			continue;
+
+		bpf_link__unpin(link);
+	}
+}
+
 void bpf_object__destroy_skeleton(struct bpf_object_skeleton *s)
 {
 	if (!s)

tools/lib/bpf/libbpf.h

@@ -28,6 +28,8 @@ LIBBPF_API __u32 libbpf_major_version(void);
 LIBBPF_API __u32 libbpf_minor_version(void);
 LIBBPF_API const char *libbpf_version_string(void);
 
+#define DEFAULT_BPFFS "/sys/fs/bpf"
+
 enum libbpf_errno {
 	__LIBBPF_ERRNO__START = 4000,
 
@@ -91,7 +93,7 @@ struct bpf_object_open_opts {
 	bool relaxed_core_relocs;
 	/* maps that set the 'pinning' attribute in their definition will have
 	 * their pin_path attribute set to a file in this directory, and be
-	 * auto-pinned to that path on load; defaults to "/sys/fs/bpf".
+	 * auto-pinned to that path on load; defaults to DEFAULT_BPFFS.
 	 */
 	const char *pin_root_path;
 
@@ -190,7 +192,7 @@ bpf_object__open_xattr(struct bpf_object_open_attr *attr);
 
 enum libbpf_pin_type {
 	LIBBPF_PIN_NONE,
-	/* PIN_BY_NAME: pin maps by name (in /sys/fs/bpf by default) */
+	/* PIN_BY_NAME: pin maps by name (in DEFAULT_BPFFS by default) */
 	LIBBPF_PIN_BY_NAME,
 };
 
@@ -1425,6 +1427,10 @@ bpf_object__open_skeleton(struct bpf_object_skeleton *s,
 LIBBPF_API int bpf_object__load_skeleton(struct bpf_object_skeleton *s);
 LIBBPF_API int bpf_object__attach_skeleton(struct bpf_object_skeleton *s);
 LIBBPF_API void bpf_object__detach_skeleton(struct bpf_object_skeleton *s);
+LIBBPF_API int
+bpf_object__pin_skeleton_prog(struct bpf_object_skeleton *s, const char *path);
+LIBBPF_API void
+bpf_object__unpin_skeleton_prog(struct bpf_object_skeleton *s);
 LIBBPF_API void bpf_object__destroy_skeleton(struct bpf_object_skeleton *s);
 
 struct bpf_var_skeleton {

tools/lib/bpf/libbpf.map

@@ -55,6 +55,8 @@ LIBBPF_0.0.1 {
 		bpf_object__unload;
 		bpf_object__unpin_maps;
 		bpf_object__unpin_programs;
+		bpf_object__pin_skeleton_prog;
+		bpf_object__unpin_skeleton_prog;
 		bpf_perf_event_read_simple;
 		bpf_prog_attach;
 		bpf_prog_detach;