1 files changed, 118 insertions, 1 deletions

diff --git a/tools/lib/bpf/features.c b/tools/lib/bpf/features.c
index 760657f5224c..4f19a0d79b0c 100644
--- a/tools/lib/bpf/features.c
+++ b/tools/lib/bpf/features.c
@@ -6,7 +6,6 @@
 #include "libbpf.h"
 #include "libbpf_common.h"
 #include "libbpf_internal.h"
-#include "str_error.h"
 
 static inline __u64 ptr_to_u64(const void *ptr)
 {
@@ -507,6 +506,115 @@ static int probe_kern_arg_ctx_tag(int token_fd)
 	return probe_fd(prog_fd);
 }
 
+static int probe_ldimm64_full_range_off(int token_fd)
+{
+	char log_buf[1024];
+	int prog_fd, map_fd;
+	int ret;
+	LIBBPF_OPTS(bpf_map_create_opts, map_opts,
+		.token_fd = token_fd,
+		.map_flags = token_fd ? BPF_F_TOKEN_FD : 0,
+	);
+	LIBBPF_OPTS(bpf_prog_load_opts, prog_opts,
+		.token_fd = token_fd,
+		.prog_flags = token_fd ? BPF_F_TOKEN_FD : 0,
+		.log_buf = log_buf,
+		.log_size = sizeof(log_buf),
+	);
+	struct bpf_insn insns[] = {
+		BPF_LD_MAP_VALUE(BPF_REG_1, 0, 1UL << 30),
+		BPF_EXIT_INSN(),
+	};
+	int insn_cnt = ARRAY_SIZE(insns);
+
+	map_fd = bpf_map_create(BPF_MAP_TYPE_ARRAY, "arr", sizeof(int), 1, 1, &map_opts);
+	if (map_fd < 0) {
+		ret = -errno;
+		pr_warn("Error in %s(): %s. Couldn't create simple array map.\n",
+			__func__, errstr(ret));
+		return ret;
+	}
+	insns[0].imm = map_fd;
+
+	log_buf[0] = '\0';
+	prog_fd = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, "global_reloc", "GPL", insns, insn_cnt, &prog_opts);
+	ret = -errno;
+
+	close(map_fd);
+
+	if (prog_fd >= 0) {
+		pr_warn("Error in %s(): Program loading unexpectedly succeeded.\n", __func__);
+		close(prog_fd);
+		return -EINVAL;
+	}
+
+	/*
+	 * Feature is allowed if we're not failing with the error message
+	 * "direct value offset of %u is not allowed" removed in
+	 * 12a1fe6e12db ("bpf/verifier: Do not limit maximum direct offset into arena map").
+	 * We should instead fail with "invalid access to map value pointer".
+	 * Ensure we match with one of the two and we're not failing with a
+	 * different, unexpected message.
+	 */
+	if (strstr(log_buf, "direct value offset of"))
+		return 0;
+
+	if (!strstr(log_buf, "invalid access to map value pointer")) {
+		pr_warn("Error in %s(): Program unexpectedly failed with message: %s.\n",
+			__func__, log_buf);
+		return ret;
+	}
+
+	return 1;
+}
+
+#ifdef __x86_64__
+
+#ifndef __NR_uprobe
+#define __NR_uprobe 336
+#endif
+
+static int probe_uprobe_syscall(int token_fd)
+{
+	/*
+	 * If kernel supports uprobe() syscall, it will return -ENXIO when called
+	 * from the outside of a kernel-generated uprobe trampoline.
+	 */
+	return syscall(__NR_uprobe) < 0 && errno == ENXIO;
+}
+#else
+static int probe_uprobe_syscall(int token_fd)
+{
+	return 0;
+}
+#endif
+
+static int probe_kern_btf_layout(int token_fd)
+{
+	static const char strs[] = "\0int";
+	__u32 types[] = {
+		/* int */
+		BTF_TYPE_INT_ENC(1, BTF_INT_SIGNED, 0, 32, 4),
+	};
+	struct btf_layout layout[] = {
+		{ 0,			0,	0 },
+		{ sizeof(__u32),	0,	0 },
+	};
+	struct btf_header hdr = {
+		.magic = BTF_MAGIC,
+		.version = BTF_VERSION,
+		.hdr_len = sizeof(struct btf_header),
+		.type_len = sizeof(types),
+		.str_off = sizeof(types) + sizeof(layout),
+		.str_len = sizeof(strs),
+		.layout_off = sizeof(types),
+		.layout_len = sizeof(layout),
+	};
+
+	return probe_fd(libbpf__load_raw_btf_hdr(&hdr, (char *)types, strs,
+						 (char *)layout, token_fd));
+}
+
 typedef int (*feature_probe_fn)(int /* token_fd */);
 
 static struct kern_feature_cache feature_cache;
@@ -582,6 +690,15 @@ static struct kern_feature_desc {
 	[FEAT_BTF_QMARK_DATASEC] = {
 		"BTF DATASEC names starting from '?'", probe_kern_btf_qmark_datasec,
 	},
+	[FEAT_LDIMM64_FULL_RANGE_OFF] = {
+		"full range LDIMM64 support", probe_ldimm64_full_range_off,
+	},
+	[FEAT_UPROBE_SYSCALL] = {
+		"kernel supports uprobe syscall", probe_uprobe_syscall,
+	},
+	[FEAT_BTF_LAYOUT] = {
+		"kernel supports BTF layout", probe_kern_btf_layout,
+	},
 };
 
 bool feat_supported(struct kern_feature_cache *cache, enum kern_feature_id feat_id)