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

Daniel Borkmann says:

====================
pull-request: bpf-next 2021-01-16

1) Extend atomic operations to the BPF instruction set along with x86-64 JIT support,
   that is, atomic{,64}_{xchg,cmpxchg,fetch_{add,and,or,xor}}, from Brendan Jackman.

2) Add support for using kernel module global variables (__ksym externs in BPF
   programs) retrieved via module's BTF, from Andrii Nakryiko.

3) Generalize BPF stackmap's buildid retrieval and add support to have buildid
   stored in mmap2 event for perf, from Jiri Olsa.

4) Various fixes for cross-building BPF sefltests out-of-tree which then will
   unblock wider automated testing on ARM hardware, from Jean-Philippe Brucker.

5) Allow to retrieve SOL_SOCKET opts from sock_addr progs, from Daniel Borkmann.

6) Clean up driver's XDP buffer init and split into two helpers to init per-
   descriptor and non-changing fields during processing, from Lorenzo Bianconi.

7) Minor misc improvements to libbpf & bpftool, from Ian Rogers.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (41 commits)
  perf: Add build id data in mmap2 event
  bpf: Add size arg to build_id_parse function
  bpf: Move stack_map_get_build_id into lib
  bpf: Document new atomic instructions
  bpf: Add tests for new BPF atomic operations
  bpf: Add bitwise atomic instructions
  bpf: Pull out a macro for interpreting atomic ALU operations
  bpf: Add instructions for atomic_[cmp]xchg
  bpf: Add BPF_FETCH field / create atomic_fetch_add instruction
  bpf: Move BPF_STX reserved field check into BPF_STX verifier code
  bpf: Rename BPF_XADD and prepare to encode other atomics in .imm
  bpf: x86: Factor out a lookup table for some ALU opcodes
  bpf: x86: Factor out emission of REX byte
  bpf: x86: Factor out emission of ModR/M for *(reg + off)
  tools/bpftool: Add -Wall when building BPF programs
  bpf, libbpf: Avoid unused function warning on bpf_tail_call_static
  selftests/bpf: Install btf_dump test cases
  selftests/bpf: Fix installation of urandom_read
  selftests/bpf: Move generated test files to $(TEST_GEN_FILES)
  selftests/bpf: Fix out-of-tree build
  ...
====================

Link: https://lore.kernel.org/r/20210116012922.17823-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

3 files changed, 158 insertions, 8 deletions

diff --git a/lib/Makefile b/lib/Makefile
index afeff05fa8c5..a6b160c3a4fa 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -36,7 +36,8 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \
 	 flex_proportions.o ratelimit.o show_mem.o \
 	 is_single_threaded.o plist.o decompress.o kobject_uevent.o \
 	 earlycpio.o seq_buf.o siphash.o dec_and_lock.o \
-	 nmi_backtrace.o nodemask.o win_minmax.o memcat_p.o
+	 nmi_backtrace.o nodemask.o win_minmax.o memcat_p.o \
+	 buildid.o
 
 lib-$(CONFIG_PRINTK) += dump_stack.o
 lib-$(CONFIG_SMP) += cpumask.o
diff --git a/lib/buildid.c b/lib/buildid.c
new file mode 100644
index 000000000000..6156997c3895
--- /dev/null
+++ b/lib/buildid.c
@@ -0,0 +1,149 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/buildid.h>
+#include <linux/elf.h>
+#include <linux/pagemap.h>
+
+#define BUILD_ID 3
+/*
+ * Parse build id from the note segment. This logic can be shared between
+ * 32-bit and 64-bit system, because Elf32_Nhdr and Elf64_Nhdr are
+ * identical.
+ */
+static inline int parse_build_id(void *page_addr,
+				 unsigned char *build_id,
+				 __u32 *size,
+				 void *note_start,
+				 Elf32_Word note_size)
+{
+	Elf32_Word note_offs = 0, new_offs;
+
+	/* check for overflow */
+	if (note_start < page_addr || note_start + note_size < note_start)
+		return -EINVAL;
+
+	/* only supports note that fits in the first page */
+	if (note_start + note_size > page_addr + PAGE_SIZE)
+		return -EINVAL;
+
+	while (note_offs + sizeof(Elf32_Nhdr) < note_size) {
+		Elf32_Nhdr *nhdr = (Elf32_Nhdr *)(note_start + note_offs);
+
+		if (nhdr->n_type == BUILD_ID &&
+		    nhdr->n_namesz == sizeof("GNU") &&
+		    nhdr->n_descsz > 0 &&
+		    nhdr->n_descsz <= BUILD_ID_SIZE_MAX) {
+			memcpy(build_id,
+			       note_start + note_offs +
+			       ALIGN(sizeof("GNU"), 4) + sizeof(Elf32_Nhdr),
+			       nhdr->n_descsz);
+			memset(build_id + nhdr->n_descsz, 0,
+			       BUILD_ID_SIZE_MAX - nhdr->n_descsz);
+			if (size)
+				*size = nhdr->n_descsz;
+			return 0;
+		}
+		new_offs = note_offs + sizeof(Elf32_Nhdr) +
+			ALIGN(nhdr->n_namesz, 4) + ALIGN(nhdr->n_descsz, 4);
+		if (new_offs <= note_offs)  /* overflow */
+			break;
+		note_offs = new_offs;
+	}
+	return -EINVAL;
+}
+
+/* Parse build ID from 32-bit ELF */
+static int get_build_id_32(void *page_addr, unsigned char *build_id,
+			   __u32 *size)
+{
+	Elf32_Ehdr *ehdr = (Elf32_Ehdr *)page_addr;
+	Elf32_Phdr *phdr;
+	int i;
+
+	/* only supports phdr that fits in one page */
+	if (ehdr->e_phnum >
+	    (PAGE_SIZE - sizeof(Elf32_Ehdr)) / sizeof(Elf32_Phdr))
+		return -EINVAL;
+
+	phdr = (Elf32_Phdr *)(page_addr + sizeof(Elf32_Ehdr));
+
+	for (i = 0; i < ehdr->e_phnum; ++i) {
+		if (phdr[i].p_type == PT_NOTE &&
+		    !parse_build_id(page_addr, build_id, size,
+				    page_addr + phdr[i].p_offset,
+				    phdr[i].p_filesz))
+			return 0;
+	}
+	return -EINVAL;
+}
+
+/* Parse build ID from 64-bit ELF */
+static int get_build_id_64(void *page_addr, unsigned char *build_id,
+			   __u32 *size)
+{
+	Elf64_Ehdr *ehdr = (Elf64_Ehdr *)page_addr;
+	Elf64_Phdr *phdr;
+	int i;
+
+	/* only supports phdr that fits in one page */
+	if (ehdr->e_phnum >
+	    (PAGE_SIZE - sizeof(Elf64_Ehdr)) / sizeof(Elf64_Phdr))
+		return -EINVAL;
+
+	phdr = (Elf64_Phdr *)(page_addr + sizeof(Elf64_Ehdr));
+
+	for (i = 0; i < ehdr->e_phnum; ++i) {
+		if (phdr[i].p_type == PT_NOTE &&
+		    !parse_build_id(page_addr, build_id, size,
+				    page_addr + phdr[i].p_offset,
+				    phdr[i].p_filesz))
+			return 0;
+	}
+	return -EINVAL;
+}
+
+/*
+ * Parse build ID of ELF file mapped to vma
+ * @vma:      vma object
+ * @build_id: buffer to store build id, at least BUILD_ID_SIZE long
+ * @size:     returns actual build id size in case of success
+ *
+ * Returns 0 on success, otherwise error (< 0).
+ */
+int build_id_parse(struct vm_area_struct *vma, unsigned char *build_id,
+		   __u32 *size)
+{
+	Elf32_Ehdr *ehdr;
+	struct page *page;
+	void *page_addr;
+	int ret;
+
+	/* only works for page backed storage  */
+	if (!vma->vm_file)
+		return -EINVAL;
+
+	page = find_get_page(vma->vm_file->f_mapping, 0);
+	if (!page)
+		return -EFAULT;	/* page not mapped */
+
+	ret = -EINVAL;
+	page_addr = kmap_atomic(page);
+	ehdr = (Elf32_Ehdr *)page_addr;
+
+	/* compare magic x7f "ELF" */
+	if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) != 0)
+		goto out;
+
+	/* only support executable file and shared object file */
+	if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN)
+		goto out;
+
+	if (ehdr->e_ident[EI_CLASS] == ELFCLASS32)
+		ret = get_build_id_32(page_addr, build_id, size);
+	else if (ehdr->e_ident[EI_CLASS] == ELFCLASS64)
+		ret = get_build_id_64(page_addr, build_id, size);
+out:
+	kunmap_atomic(page_addr);
+	put_page(page);
+	return ret;
+}
diff --git a/lib/test_bpf.c b/lib/test_bpf.c
index ca7d635bccd9..49ec9e8d8aed 100644
--- a/lib/test_bpf.c
+++ b/lib/test_bpf.c
@@ -4295,13 +4295,13 @@ static struct bpf_test tests[] = {
 		{ { 0, 0xffffffff } },
 		.stack_depth = 40,
 	},
-	/* BPF_STX | BPF_XADD | BPF_W/DW */
+	/* BPF_STX | BPF_ATOMIC | BPF_W/DW */
 	{
 		"STX_XADD_W: Test: 0x12 + 0x10 = 0x22",
 		.u.insns_int = {
 			BPF_ALU32_IMM(BPF_MOV, R0, 0x12),
 			BPF_ST_MEM(BPF_W, R10, -40, 0x10),
-			BPF_STX_XADD(BPF_W, R10, R0, -40),
+			BPF_ATOMIC_OP(BPF_W, BPF_ADD, R10, R0, -40),
 			BPF_LDX_MEM(BPF_W, R0, R10, -40),
 			BPF_EXIT_INSN(),
 		},
@@ -4316,7 +4316,7 @@ static struct bpf_test tests[] = {
 			BPF_ALU64_REG(BPF_MOV, R1, R10),
 			BPF_ALU32_IMM(BPF_MOV, R0, 0x12),
 			BPF_ST_MEM(BPF_W, R10, -40, 0x10),
-			BPF_STX_XADD(BPF_W, R10, R0, -40),
+			BPF_ATOMIC_OP(BPF_W, BPF_ADD, R10, R0, -40),
 			BPF_ALU64_REG(BPF_MOV, R0, R10),
 			BPF_ALU64_REG(BPF_SUB, R0, R1),
 			BPF_EXIT_INSN(),
@@ -4331,7 +4331,7 @@ static struct bpf_test tests[] = {
 		.u.insns_int = {
 			BPF_ALU32_IMM(BPF_MOV, R0, 0x12),
 			BPF_ST_MEM(BPF_W, R10, -40, 0x10),
-			BPF_STX_XADD(BPF_W, R10, R0, -40),
+			BPF_ATOMIC_OP(BPF_W, BPF_ADD, R10, R0, -40),
 			BPF_EXIT_INSN(),
 		},
 		INTERNAL,
@@ -4352,7 +4352,7 @@ static struct bpf_test tests[] = {
 		.u.insns_int = {
 			BPF_ALU32_IMM(BPF_MOV, R0, 0x12),
 			BPF_ST_MEM(BPF_DW, R10, -40, 0x10),
-			BPF_STX_XADD(BPF_DW, R10, R0, -40),
+			BPF_ATOMIC_OP(BPF_DW, BPF_ADD, R10, R0, -40),
 			BPF_LDX_MEM(BPF_DW, R0, R10, -40),
 			BPF_EXIT_INSN(),
 		},
@@ -4367,7 +4367,7 @@ static struct bpf_test tests[] = {
 			BPF_ALU64_REG(BPF_MOV, R1, R10),
 			BPF_ALU32_IMM(BPF_MOV, R0, 0x12),
 			BPF_ST_MEM(BPF_DW, R10, -40, 0x10),
-			BPF_STX_XADD(BPF_DW, R10, R0, -40),
+			BPF_ATOMIC_OP(BPF_DW, BPF_ADD, R10, R0, -40),
 			BPF_ALU64_REG(BPF_MOV, R0, R10),
 			BPF_ALU64_REG(BPF_SUB, R0, R1),
 			BPF_EXIT_INSN(),
@@ -4382,7 +4382,7 @@ static struct bpf_test tests[] = {
 		.u.insns_int = {
 			BPF_ALU32_IMM(BPF_MOV, R0, 0x12),
 			BPF_ST_MEM(BPF_DW, R10, -40, 0x10),
-			BPF_STX_XADD(BPF_DW, R10, R0, -40),
+			BPF_ATOMIC_OP(BPF_DW, BPF_ADD, R10, R0, -40),
 			BPF_EXIT_INSN(),
 		},
 		INTERNAL,