From 0738599856542bab0ebcd73cab9d8f15bddedcee Mon Sep 17 00:00:00 2001
From: Vladimir Isaev <isaev@synopsys.com>
Date: Sat, 9 Apr 2022 01:44:42 +0300
Subject: libbpf: Add ARC support to bpf_tracing.h

Add PT_REGS macros suitable for ARCompact and ARCv2.

Signed-off-by: Vladimir Isaev <isaev@synopsys.com>
Signed-off-by: Sergey Matyukevich <geomatsi@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20220408224442.599566-1-geomatsi@gmail.com
---
 tools/lib/bpf/bpf_tracing.h | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

(limited to 'tools/lib')

diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h
index e3a8c947e89f..01ce121c302d 100644
--- a/tools/lib/bpf/bpf_tracing.h
+++ b/tools/lib/bpf/bpf_tracing.h
@@ -27,6 +27,9 @@
 #elif defined(__TARGET_ARCH_riscv)
 	#define bpf_target_riscv
 	#define bpf_target_defined
+#elif defined(__TARGET_ARCH_arc)
+	#define bpf_target_arc
+	#define bpf_target_defined
 #else
 
 /* Fall back to what the compiler says */
@@ -54,6 +57,9 @@
 #elif defined(__riscv) && __riscv_xlen == 64
 	#define bpf_target_riscv
 	#define bpf_target_defined
+#elif defined(__arc__)
+	#define bpf_target_arc
+	#define bpf_target_defined
 #endif /* no compiler target */
 
 #endif
@@ -233,6 +239,23 @@ struct pt_regs___arm64 {
 /* riscv does not select ARCH_HAS_SYSCALL_WRAPPER. */
 #define PT_REGS_SYSCALL_REGS(ctx) ctx
 
+#elif defined(bpf_target_arc)
+
+/* arc provides struct user_pt_regs instead of struct pt_regs to userspace */
+#define __PT_REGS_CAST(x) ((const struct user_regs_struct *)(x))
+#define __PT_PARM1_REG scratch.r0
+#define __PT_PARM2_REG scratch.r1
+#define __PT_PARM3_REG scratch.r2
+#define __PT_PARM4_REG scratch.r3
+#define __PT_PARM5_REG scratch.r4
+#define __PT_RET_REG scratch.blink
+#define __PT_FP_REG __unsupported__
+#define __PT_RC_REG scratch.r0
+#define __PT_SP_REG scratch.sp
+#define __PT_IP_REG scratch.ret
+/* arc does not select ARCH_HAS_SYSCALL_WRAPPER. */
+#define PT_REGS_SYSCALL_REGS(ctx) ctx
+
 #endif
 
 #if defined(bpf_target_defined)
-- 
cgit v1.2.3


From d252a4a499a07bec21c65873f605c3a1ef52ffed Mon Sep 17 00:00:00 2001
From: Runqing Yang <rainkin1993@gmail.com>
Date: Sat, 9 Apr 2022 22:49:28 +0800
Subject: libbpf: Fix a bug with checking bpf_probe_read_kernel() support in
 old kernels

Background:
Libbpf automatically replaces calls to BPF bpf_probe_read_{kernel,user}
[_str]() helpers with bpf_probe_read[_str](), if libbpf detects that
kernel doesn't support new APIs. Specifically, libbpf invokes the
probe_kern_probe_read_kernel function to load a small eBPF program into
the kernel in which bpf_probe_read_kernel API is invoked and lets the
kernel checks whether the new API is valid. If the loading fails, libbpf
considers the new API invalid and replaces it with the old API.

static int probe_kern_probe_read_kernel(void)
{
	struct bpf_insn insns[] = {
		BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),	/* r1 = r10 (fp) */
		BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),	/* r1 += -8 */
		BPF_MOV64_IMM(BPF_REG_2, 8),		/* r2 = 8 */
		BPF_MOV64_IMM(BPF_REG_3, 0),		/* r3 = 0 */
		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_probe_read_kernel),
		BPF_EXIT_INSN(),
	};
	int fd, insn_cnt = ARRAY_SIZE(insns);

	fd = bpf_prog_load(BPF_PROG_TYPE_KPROBE, NULL,
                           "GPL", insns, insn_cnt, NULL);
	return probe_fd(fd);
}

Bug:
On older kernel versions [0], the kernel checks whether the version
number provided in the bpf syscall, matches the LINUX_VERSION_CODE.
If not matched, the bpf syscall fails. eBPF However, the
probe_kern_probe_read_kernel code does not set the kernel version
number provided to the bpf syscall, which causes the loading process
alwasys fails for old versions. It means that libbpf will replace the
new API with the old one even the kernel supports the new one.

Solution:
After a discussion in [1], the solution is using BPF_PROG_TYPE_TRACEPOINT
program type instead of BPF_PROG_TYPE_KPROBE because kernel does not
enfoce version check for tracepoint programs. I test the patch in old
kernels (4.18 and 4.19) and it works well.

  [0] https://elixir.bootlin.com/linux/v4.19/source/kernel/bpf/syscall.c#L1360
  [1] Closes: https://github.com/libbpf/libbpf/issues/473

Signed-off-by: Runqing Yang <rainkin1993@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220409144928.27499-1-rainkin1993@gmail.com
---
 tools/lib/bpf/libbpf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'tools/lib')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 465b7c0996f1..bf4f7ac54ebf 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -4594,7 +4594,7 @@ static int probe_kern_probe_read_kernel(void)
 	};
 	int fd, insn_cnt = ARRAY_SIZE(insns);
 
-	fd = bpf_prog_load(BPF_PROG_TYPE_KPROBE, NULL, "GPL", insns, insn_cnt, NULL);
+	fd = bpf_prog_load(BPF_PROG_TYPE_TRACEPOINT, NULL, "GPL", insns, insn_cnt, NULL);
 	return probe_fd(fd);
 }
 
-- 
cgit v1.2.3


From 0f8619929c572609f7cdfa366d0424c2c2552e60 Mon Sep 17 00:00:00 2001
From: Alan Maguire <alan.maguire@oracle.com>
Date: Mon, 11 Apr 2022 16:21:36 +0100
Subject: libbpf: Usdt aarch64 arg parsing support

Parsing of USDT arguments is architecture-specific. On aarch64 it is
relatively easy since registers used are x[0-31] and sp. Format is
slightly different compared to x86_64. Possible forms are:

- "size@[reg[,offset]]" for dereferences, e.g. "-8@[sp,76]" and "-4@[sp]";
- "size@reg" for register values, e.g. "-4@x0";
- "size@value" for raw values, e.g. "-8@1".

Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1649690496-1902-2-git-send-email-alan.maguire@oracle.com
---
 tools/lib/bpf/usdt.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 76 insertions(+)

(limited to 'tools/lib')

diff --git a/tools/lib/bpf/usdt.c b/tools/lib/bpf/usdt.c
index acf2d99a9e77..934c25301ac1 100644
--- a/tools/lib/bpf/usdt.c
+++ b/tools/lib/bpf/usdt.c
@@ -1324,6 +1324,82 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec
 	return len;
 }
 
+#elif defined(__aarch64__)
+
+static int calc_pt_regs_off(const char *reg_name)
+{
+	int reg_num;
+
+	if (sscanf(reg_name, "x%d", &reg_num) == 1) {
+		if (reg_num >= 0 && reg_num < 31)
+			return offsetof(struct user_pt_regs, regs[reg_num]);
+	} else if (strcmp(reg_name, "sp") == 0) {
+		return offsetof(struct user_pt_regs, sp);
+	}
+	pr_warn("usdt: unrecognized register '%s'\n", reg_name);
+	return -ENOENT;
+}
+
+static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg)
+{
+	char *reg_name = NULL;
+	int arg_sz, len, reg_off;
+	long off;
+
+	if (sscanf(arg_str, " %d @ \[ %m[a-z0-9], %ld ] %n", &arg_sz, &reg_name, &off, &len) == 3) {
+		/* Memory dereference case, e.g., -4@[sp, 96] */
+		arg->arg_type = USDT_ARG_REG_DEREF;
+		arg->val_off = off;
+		reg_off = calc_pt_regs_off(reg_name);
+		free(reg_name);
+		if (reg_off < 0)
+			return reg_off;
+		arg->reg_off = reg_off;
+	} else if (sscanf(arg_str, " %d @ \[ %m[a-z0-9] ] %n", &arg_sz, &reg_name, &len) == 2) {
+		/* Memory dereference case, e.g., -4@[sp] */
+		arg->arg_type = USDT_ARG_REG_DEREF;
+		arg->val_off = 0;
+		reg_off = calc_pt_regs_off(reg_name);
+		free(reg_name);
+		if (reg_off < 0)
+			return reg_off;
+		arg->reg_off = reg_off;
+	} else if (sscanf(arg_str, " %d @ %ld %n", &arg_sz, &off, &len) == 2) {
+		/* Constant value case, e.g., 4@5 */
+		arg->arg_type = USDT_ARG_CONST;
+		arg->val_off = off;
+		arg->reg_off = 0;
+	} else if (sscanf(arg_str, " %d @ %m[a-z0-9] %n", &arg_sz, &reg_name, &len) == 2) {
+		/* Register read case, e.g., -8@x4 */
+		arg->arg_type = USDT_ARG_REG;
+		arg->val_off = 0;
+		reg_off = calc_pt_regs_off(reg_name);
+		free(reg_name);
+		if (reg_off < 0)
+			return reg_off;
+		arg->reg_off = reg_off;
+	} else {
+		pr_warn("usdt: unrecognized arg #%d spec '%s'\n", arg_num, arg_str);
+		return -EINVAL;
+	}
+
+	arg->arg_signed = arg_sz < 0;
+	if (arg_sz < 0)
+		arg_sz = -arg_sz;
+
+	switch (arg_sz) {
+	case 1: case 2: case 4: case 8:
+		arg->arg_bitshift = 64 - arg_sz * 8;
+		break;
+	default:
+		pr_warn("usdt: unsupported arg #%d (spec '%s') size: %d\n",
+			arg_num, arg_str, arg_sz);
+		return -EINVAL;
+	}
+
+	return len;
+}
+
 #else
 
 static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg)
-- 
cgit v1.2.3


From a3820c48111247f4ec2ca2949597f8fa57d2c424 Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko <andrii@kernel.org>
Date: Mon, 18 Apr 2022 17:24:50 -0700
Subject: libbpf: Support opting out from autoloading BPF programs
 declaratively

Establish SEC("?abc") naming convention (i.e., adding question mark in
front of otherwise normal section name) that allows to set corresponding
program's autoload property to false. This is effectively just
a declarative way to do bpf_program__set_autoload(prog, false).

Having a way to do this declaratively in BPF code itself is useful and
convenient for various scenarios. E.g., for testing, when BPF object
consists of multiple independent BPF programs that each needs to be
tested separately. Opting out all of them by default and then setting
autoload to true for just one of them at a time simplifies testing code
(see next patch for few conversions in BPF selftests taking advantage of
this new feature).

Another real-world use case is in libbpf-tools for cases when different
BPF programs have to be picked depending on particulars of the host
kernel due to various incompatible changes (like kernel function renames
or signature change, or to pick kprobe vs fentry depending on
corresponding kernel support for the latter). Marking all the different
BPF program candidates as non-autoloaded declaratively makes this more
obvious in BPF source code and allows simpler code in user-space code.

When BPF program marked as SEC("?abc") it is otherwise treated just like
SEC("abc") and bpf_program__section_name() reported will be "abc".

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220419002452.632125-1-andrii@kernel.org
---
 tools/lib/bpf/libbpf.c | 31 +++++++++++++++++++++----------
 1 file changed, 21 insertions(+), 10 deletions(-)

(limited to 'tools/lib')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index bf4f7ac54ebf..68cc134d070d 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -302,7 +302,7 @@ struct bpf_program {
 	void *priv;
 	bpf_program_clear_priv_t clear_priv;
 
-	bool load;
+	bool autoload;
 	bool mark_btf_static;
 	enum bpf_prog_type type;
 	enum bpf_attach_type expected_attach_type;
@@ -672,7 +672,18 @@ bpf_object__init_prog(struct bpf_object *obj, struct bpf_program *prog,
 	prog->insns_cnt = prog->sec_insn_cnt;
 
 	prog->type = BPF_PROG_TYPE_UNSPEC;
-	prog->load = true;
+
+	/* libbpf's convention for SEC("?abc...") is that it's just like
+	 * SEC("abc...") but the corresponding bpf_program starts out with
+	 * autoload set to false.
+	 */
+	if (sec_name[0] == '?') {
+		prog->autoload = false;
+		/* from now on forget there was ? in section name */
+		sec_name++;
+	} else {
+		prog->autoload = true;
+	}
 
 	prog->instances.fds = NULL;
 	prog->instances.nr = -1;
@@ -2927,7 +2938,7 @@ static bool obj_needs_vmlinux_btf(const struct bpf_object *obj)
 	}
 
 	bpf_object__for_each_program(prog, obj) {
-		if (!prog->load)
+		if (!prog->autoload)
 			continue;
 		if (prog_needs_vmlinux_btf(prog))
 			return true;
@@ -5702,7 +5713,7 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
 			/* no need to apply CO-RE relocation if the program is
 			 * not going to be loaded
 			 */
-			if (!prog->load)
+			if (!prog->autoload)
 				continue;
 
 			/* adjust insn_idx from section frame of reference to the local
@@ -6363,7 +6374,7 @@ bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path)
 		 */
 		if (prog_is_subprog(obj, prog))
 			continue;
-		if (!prog->load)
+		if (!prog->autoload)
 			continue;
 
 		err = bpf_object__relocate_calls(obj, prog);
@@ -6378,7 +6389,7 @@ bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path)
 		prog = &obj->programs[i];
 		if (prog_is_subprog(obj, prog))
 			continue;
-		if (!prog->load)
+		if (!prog->autoload)
 			continue;
 		err = bpf_object__relocate_data(obj, prog);
 		if (err) {
@@ -6975,7 +6986,7 @@ bpf_object__load_progs(struct bpf_object *obj, int log_level)
 		prog = &obj->programs[i];
 		if (prog_is_subprog(obj, prog))
 			continue;
-		if (!prog->load) {
+		if (!prog->autoload) {
 			pr_debug("prog '%s': skipped loading\n", prog->name);
 			continue;
 		}
@@ -8455,7 +8466,7 @@ const char *bpf_program__title(const struct bpf_program *prog, bool needs_copy)
 
 bool bpf_program__autoload(const struct bpf_program *prog)
 {
-	return prog->load;
+	return prog->autoload;
 }
 
 int bpf_program__set_autoload(struct bpf_program *prog, bool autoload)
@@ -8463,7 +8474,7 @@ int bpf_program__set_autoload(struct bpf_program *prog, bool autoload)
 	if (prog->obj->loaded)
 		return libbpf_err(-EINVAL);
 
-	prog->load = autoload;
+	prog->autoload = autoload;
 	return 0;
 }
 
@@ -12665,7 +12676,7 @@ int bpf_object__attach_skeleton(struct bpf_object_skeleton *s)
 		struct bpf_program *prog = *s->progs[i].prog;
 		struct bpf_link **link = s->progs[i].link;
 
-		if (!prog->load)
+		if (!prog->autoload)
 			continue;
 
 		/* auto-attaching not supported for this program */
-- 
cgit v1.2.3


From 5af25a410acb8d34acb11024d752f0ea3491decf Mon Sep 17 00:00:00 2001
From: Pu Lehui <pulehui@huawei.com>
Date: Tue, 19 Apr 2022 22:52:37 +0800
Subject: libbpf: Fix usdt_cookie being cast to 32 bits

The usdt_cookie is defined as __u64, which should not be
used as a long type because it will be cast to 32 bits
in 32-bit platforms.

Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220419145238.482134-2-pulehui@huawei.com
---
 tools/lib/bpf/libbpf.c          | 2 +-
 tools/lib/bpf/libbpf_internal.h | 2 +-
 tools/lib/bpf/usdt.c            | 8 ++++----
 3 files changed, 6 insertions(+), 6 deletions(-)

(limited to 'tools/lib')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 68cc134d070d..8375021800f3 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -10993,7 +10993,7 @@ struct bpf_link *bpf_program__attach_usdt(const struct bpf_program *prog,
 	char resolved_path[512];
 	struct bpf_object *obj = prog->obj;
 	struct bpf_link *link;
-	long usdt_cookie;
+	__u64 usdt_cookie;
 	int err;
 
 	if (!OPTS_VALID(opts, bpf_uprobe_opts))
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
index 080272421f6c..054cd8e93d7c 100644
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -571,6 +571,6 @@ struct bpf_link * usdt_manager_attach_usdt(struct usdt_manager *man,
 					   const struct bpf_program *prog,
 					   pid_t pid, const char *path,
 					   const char *usdt_provider, const char *usdt_name,
-					   long usdt_cookie);
+					   __u64 usdt_cookie);
 
 #endif /* __LIBBPF_LIBBPF_INTERNAL_H */
diff --git a/tools/lib/bpf/usdt.c b/tools/lib/bpf/usdt.c
index 934c25301ac1..8e77a7260113 100644
--- a/tools/lib/bpf/usdt.c
+++ b/tools/lib/bpf/usdt.c
@@ -557,10 +557,10 @@ static int parse_usdt_note(Elf *elf, const char *path, long base_addr,
 			   GElf_Nhdr *nhdr, const char *data, size_t name_off, size_t desc_off,
 			   struct usdt_note *usdt_note);
 
-static int parse_usdt_spec(struct usdt_spec *spec, const struct usdt_note *note, long usdt_cookie);
+static int parse_usdt_spec(struct usdt_spec *spec, const struct usdt_note *note, __u64 usdt_cookie);
 
 static int collect_usdt_targets(struct usdt_manager *man, Elf *elf, const char *path, pid_t pid,
-				const char *usdt_provider, const char *usdt_name, long usdt_cookie,
+				const char *usdt_provider, const char *usdt_name, __u64 usdt_cookie,
 				struct usdt_target **out_targets, size_t *out_target_cnt)
 {
 	size_t off, name_off, desc_off, seg_cnt = 0, lib_seg_cnt = 0, target_cnt = 0;
@@ -939,7 +939,7 @@ static int allocate_spec_id(struct usdt_manager *man, struct hashmap *specs_hash
 struct bpf_link *usdt_manager_attach_usdt(struct usdt_manager *man, const struct bpf_program *prog,
 					  pid_t pid, const char *path,
 					  const char *usdt_provider, const char *usdt_name,
-					  long usdt_cookie)
+					  __u64 usdt_cookie)
 {
 	int i, fd, err, spec_map_fd, ip_map_fd;
 	LIBBPF_OPTS(bpf_uprobe_opts, opts);
@@ -1141,7 +1141,7 @@ static int parse_usdt_note(Elf *elf, const char *path, long base_addr,
 
 static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg);
 
-static int parse_usdt_spec(struct usdt_spec *spec, const struct usdt_note *note, long usdt_cookie)
+static int parse_usdt_spec(struct usdt_spec *spec, const struct usdt_note *note, __u64 usdt_cookie)
 {
 	const char *s;
 	int len;
-- 
cgit v1.2.3


From 58ca8b0572cd3bbaac60d14d2b1b4f38b389ad93 Mon Sep 17 00:00:00 2001
From: Pu Lehui <pulehui@huawei.com>
Date: Tue, 19 Apr 2022 22:52:38 +0800
Subject: libbpf: Support riscv USDT argument parsing logic

Add riscv-specific USDT argument specification parsing logic.
riscv USDT argument format is shown below:
- Memory dereference case:
  "size@off(reg)", e.g. "-8@-88(s0)"
- Constant value case:
  "size@val", e.g. "4@5"
- Register read case:
  "size@reg", e.g. "-8@a1"

s8 will be marked as poison while it's a reg of riscv, we need
to alias it in advance. Both RV32 and RV64 have been tested.

Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220419145238.482134-3-pulehui@huawei.com
---
 tools/lib/bpf/usdt.c | 107 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 107 insertions(+)

(limited to 'tools/lib')

diff --git a/tools/lib/bpf/usdt.c b/tools/lib/bpf/usdt.c
index 8e77a7260113..f1c9339cfbbc 100644
--- a/tools/lib/bpf/usdt.c
+++ b/tools/lib/bpf/usdt.c
@@ -10,6 +10,11 @@
 #include <linux/ptrace.h>
 #include <linux/kernel.h>
 
+/* s8 will be marked as poison while it's a reg of riscv */
+#if defined(__riscv)
+#define rv_s8 s8
+#endif
+
 #include "bpf.h"
 #include "libbpf.h"
 #include "libbpf_common.h"
@@ -1400,6 +1405,108 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec
 	return len;
 }
 
+#elif defined(__riscv)
+
+static int calc_pt_regs_off(const char *reg_name)
+{
+	static struct {
+		const char *name;
+		size_t pt_regs_off;
+	} reg_map[] = {
+		{ "ra", offsetof(struct user_regs_struct, ra) },
+		{ "sp", offsetof(struct user_regs_struct, sp) },
+		{ "gp", offsetof(struct user_regs_struct, gp) },
+		{ "tp", offsetof(struct user_regs_struct, tp) },
+		{ "a0", offsetof(struct user_regs_struct, a0) },
+		{ "a1", offsetof(struct user_regs_struct, a1) },
+		{ "a2", offsetof(struct user_regs_struct, a2) },
+		{ "a3", offsetof(struct user_regs_struct, a3) },
+		{ "a4", offsetof(struct user_regs_struct, a4) },
+		{ "a5", offsetof(struct user_regs_struct, a5) },
+		{ "a6", offsetof(struct user_regs_struct, a6) },
+		{ "a7", offsetof(struct user_regs_struct, a7) },
+		{ "s0", offsetof(struct user_regs_struct, s0) },
+		{ "s1", offsetof(struct user_regs_struct, s1) },
+		{ "s2", offsetof(struct user_regs_struct, s2) },
+		{ "s3", offsetof(struct user_regs_struct, s3) },
+		{ "s4", offsetof(struct user_regs_struct, s4) },
+		{ "s5", offsetof(struct user_regs_struct, s5) },
+		{ "s6", offsetof(struct user_regs_struct, s6) },
+		{ "s7", offsetof(struct user_regs_struct, s7) },
+		{ "s8", offsetof(struct user_regs_struct, rv_s8) },
+		{ "s9", offsetof(struct user_regs_struct, s9) },
+		{ "s10", offsetof(struct user_regs_struct, s10) },
+		{ "s11", offsetof(struct user_regs_struct, s11) },
+		{ "t0", offsetof(struct user_regs_struct, t0) },
+		{ "t1", offsetof(struct user_regs_struct, t1) },
+		{ "t2", offsetof(struct user_regs_struct, t2) },
+		{ "t3", offsetof(struct user_regs_struct, t3) },
+		{ "t4", offsetof(struct user_regs_struct, t4) },
+		{ "t5", offsetof(struct user_regs_struct, t5) },
+		{ "t6", offsetof(struct user_regs_struct, t6) },
+	};
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(reg_map); i++) {
+		if (strcmp(reg_name, reg_map[i].name) == 0)
+			return reg_map[i].pt_regs_off;
+	}
+
+	pr_warn("usdt: unrecognized register '%s'\n", reg_name);
+	return -ENOENT;
+}
+
+static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg)
+{
+	char *reg_name = NULL;
+	int arg_sz, len, reg_off;
+	long off;
+
+	if (sscanf(arg_str, " %d @ %ld ( %m[a-z0-9] ) %n", &arg_sz, &off, &reg_name, &len) == 3) {
+		/* Memory dereference case, e.g., -8@-88(s0) */
+		arg->arg_type = USDT_ARG_REG_DEREF;
+		arg->val_off = off;
+		reg_off = calc_pt_regs_off(reg_name);
+		free(reg_name);
+		if (reg_off < 0)
+			return reg_off;
+		arg->reg_off = reg_off;
+	} else if (sscanf(arg_str, " %d @ %ld %n", &arg_sz, &off, &len) == 2) {
+		/* Constant value case, e.g., 4@5 */
+		arg->arg_type = USDT_ARG_CONST;
+		arg->val_off = off;
+		arg->reg_off = 0;
+	} else if (sscanf(arg_str, " %d @ %m[a-z0-9] %n", &arg_sz, &reg_name, &len) == 2) {
+		/* Register read case, e.g., -8@a1 */
+		arg->arg_type = USDT_ARG_REG;
+		arg->val_off = 0;
+		reg_off = calc_pt_regs_off(reg_name);
+		free(reg_name);
+		if (reg_off < 0)
+			return reg_off;
+		arg->reg_off = reg_off;
+	} else {
+		pr_warn("usdt: unrecognized arg #%d spec '%s'\n", arg_num, arg_str);
+		return -EINVAL;
+	}
+
+	arg->arg_signed = arg_sz < 0;
+	if (arg_sz < 0)
+		arg_sz = -arg_sz;
+
+	switch (arg_sz) {
+	case 1: case 2: case 4: case 8:
+		arg->arg_bitshift = 64 - arg_sz * 8;
+		break;
+	default:
+		pr_warn("usdt: unsupported arg #%d (spec '%s') size: %d\n",
+			arg_num, arg_str, arg_sz);
+		return -EINVAL;
+	}
+
+	return len;
+}
+
 #else
 
 static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg)
-- 
cgit v1.2.3


From 93442f132b94721c7143ace7f43e51a9025f46fd Mon Sep 17 00:00:00 2001
From: Grant Seltzer <grantseltzer@gmail.com>
Date: Wed, 20 Apr 2022 12:12:24 -0400
Subject: libbpf: Add error returns to two API functions

This adds an error return to the following API functions:

- bpf_program__set_expected_attach_type()
- bpf_program__set_type()

In both cases, the error occurs when the BPF object has
already been loaded when the function is called. In this
case -EBUSY is returned.

Signed-off-by: Grant Seltzer <grantseltzer@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220420161226.86803-1-grantseltzer@gmail.com
---
 tools/lib/bpf/libbpf.c | 12 ++++++++++--
 tools/lib/bpf/libbpf.h |  6 +++---
 2 files changed, 13 insertions(+), 5 deletions(-)

(limited to 'tools/lib')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 8375021800f3..342340aee948 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -8562,9 +8562,13 @@ enum bpf_prog_type bpf_program__type(const struct bpf_program *prog)
 	return prog->type;
 }
 
-void bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type)
+int bpf_program__set_type(struct bpf_program *prog, enum bpf_prog_type type)
 {
+	if (prog->obj->loaded)
+		return libbpf_err(-EBUSY);
+
 	prog->type = type;
+	return 0;
 }
 
 static bool bpf_program__is_type(const struct bpf_program *prog,
@@ -8609,10 +8613,14 @@ enum bpf_attach_type bpf_program__expected_attach_type(const struct bpf_program
 	return prog->expected_attach_type;
 }
 
-void bpf_program__set_expected_attach_type(struct bpf_program *prog,
+int bpf_program__set_expected_attach_type(struct bpf_program *prog,
 					   enum bpf_attach_type type)
 {
+	if (prog->obj->loaded)
+		return libbpf_err(-EBUSY);
+
 	prog->expected_attach_type = type;
+	return 0;
 }
 
 __u32 bpf_program__flags(const struct bpf_program *prog)
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 63d66f1adf1a..66735623ca63 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -686,12 +686,12 @@ LIBBPF_DEPRECATED_SINCE(0, 8, "use bpf_program__set_type() instead")
 LIBBPF_API int bpf_program__set_sk_lookup(struct bpf_program *prog);
 
 LIBBPF_API enum bpf_prog_type bpf_program__type(const struct bpf_program *prog);
-LIBBPF_API void bpf_program__set_type(struct bpf_program *prog,
-				      enum bpf_prog_type type);
+LIBBPF_API int bpf_program__set_type(struct bpf_program *prog,
+				     enum bpf_prog_type type);
 
 LIBBPF_API enum bpf_attach_type
 bpf_program__expected_attach_type(const struct bpf_program *prog);
-LIBBPF_API void
+LIBBPF_API int
 bpf_program__set_expected_attach_type(struct bpf_program *prog,
 				      enum bpf_attach_type type);
 
-- 
cgit v1.2.3


From df286716321350d1ca370d5737acf5a10b20ee9e Mon Sep 17 00:00:00 2001
From: Grant Seltzer <grantseltzer@gmail.com>
Date: Wed, 20 Apr 2022 12:12:25 -0400
Subject: libbpf: Update API functions usage to check error

This updates usage of the following API functions within
libbpf so their newly added error return is checked:

- bpf_program__set_expected_attach_type()
- bpf_program__set_type()

Signed-off-by: Grant Seltzer <grantseltzer@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220420161226.86803-2-grantseltzer@gmail.com
---
 tools/lib/bpf/libbpf.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

(limited to 'tools/lib')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 342340aee948..94940497354b 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -7016,8 +7016,8 @@ static int bpf_object_init_progs(struct bpf_object *obj, const struct bpf_object
 			continue;
 		}
 
-		bpf_program__set_type(prog, prog->sec_def->prog_type);
-		bpf_program__set_expected_attach_type(prog, prog->sec_def->expected_attach_type);
+		prog->type = prog->sec_def->prog_type;
+		prog->expected_attach_type = prog->sec_def->expected_attach_type;
 
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
@@ -8582,8 +8582,7 @@ int bpf_program__set_##NAME(struct bpf_program *prog)		\
 {								\
 	if (!prog)						\
 		return libbpf_err(-EINVAL);			\
-	bpf_program__set_type(prog, TYPE);			\
-	return 0;						\
+	return bpf_program__set_type(prog, TYPE);			\
 }								\
 								\
 bool bpf_program__is_##NAME(const struct bpf_program *prog)	\
@@ -9690,9 +9689,8 @@ static int bpf_prog_load_xattr2(const struct bpf_prog_load_attr *attr,
 		 * bpf_object__open guessed
 		 */
 		if (attr->prog_type != BPF_PROG_TYPE_UNSPEC) {
-			bpf_program__set_type(prog, attr->prog_type);
-			bpf_program__set_expected_attach_type(prog,
-							      attach_type);
+			prog->type = attr->prog_type;
+			prog->expected_attach_type = attach_type;
 		}
 		if (bpf_program__type(prog) == BPF_PROG_TYPE_UNSPEC) {
 			/*
-- 
cgit v1.2.3


From a66ab9a9e66ab868de7063622d91442181deba0f Mon Sep 17 00:00:00 2001
From: Grant Seltzer <grantseltzer@gmail.com>
Date: Wed, 20 Apr 2022 12:12:26 -0400
Subject: libbpf: Add documentation to API functions

This adds documentation for the following API functions:

- bpf_program__set_expected_attach_type()
- bpf_program__set_type()
- bpf_program__set_attach_target()
- bpf_program__attach()
- bpf_program__pin()
- bpf_program__unpin()

Signed-off-by: Grant Seltzer <grantseltzer@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220420161226.86803-3-grantseltzer@gmail.com
---
 tools/lib/bpf/libbpf.h | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 76 insertions(+)

(limited to 'tools/lib')

diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 66735623ca63..cdbfee60ea3e 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -378,7 +378,31 @@ struct bpf_link;
 LIBBPF_API struct bpf_link *bpf_link__open(const char *path);
 LIBBPF_API int bpf_link__fd(const struct bpf_link *link);
 LIBBPF_API const char *bpf_link__pin_path(const struct bpf_link *link);
+/**
+ * @brief **bpf_link__pin()** pins the BPF link to a file
+ * in the BPF FS specified by a path. This increments the links
+ * reference count, allowing it to stay loaded after the process
+ * which loaded it has exited.
+ *
+ * @param link BPF link to pin, must already be loaded
+ * @param path file path in a BPF file system
+ * @return 0, on success; negative error code, otherwise
+ */
+
 LIBBPF_API int bpf_link__pin(struct bpf_link *link, const char *path);
+
+/**
+ * @brief **bpf_link__unpin()** unpins the BPF link from a file
+ * in the BPFFS specified by a path. This decrements the links
+ * reference count.
+ *
+ * The file pinning the BPF link can also be unlinked by a different
+ * process in which case this function will return an error.
+ *
+ * @param prog BPF program to unpin
+ * @param path file path to the pin in a BPF file system
+ * @return 0, on success; negative error code, otherwise
+ */
 LIBBPF_API int bpf_link__unpin(struct bpf_link *link);
 LIBBPF_API int bpf_link__update_program(struct bpf_link *link,
 					struct bpf_program *prog);
@@ -386,6 +410,22 @@ LIBBPF_API void bpf_link__disconnect(struct bpf_link *link);
 LIBBPF_API int bpf_link__detach(struct bpf_link *link);
 LIBBPF_API int bpf_link__destroy(struct bpf_link *link);
 
+/**
+ * @brief **bpf_program__attach()** is a generic function for attaching
+ * a BPF program based on auto-detection of program type, attach type,
+ * and extra paremeters, where applicable.
+ *
+ * @param prog BPF program to attach
+ * @return Reference to the newly created BPF link; or NULL is returned on error,
+ * error code is stored in errno
+ *
+ * This is supported for:
+ *   - kprobe/kretprobe (depends on SEC() definition)
+ *   - uprobe/uretprobe (depends on SEC() definition)
+ *   - tracepoint
+ *   - raw tracepoint
+ *   - tracing programs (typed raw TP/fentry/fexit/fmod_ret)
+ */
 LIBBPF_API struct bpf_link *
 bpf_program__attach(const struct bpf_program *prog);
 
@@ -686,11 +726,36 @@ LIBBPF_DEPRECATED_SINCE(0, 8, "use bpf_program__set_type() instead")
 LIBBPF_API int bpf_program__set_sk_lookup(struct bpf_program *prog);
 
 LIBBPF_API enum bpf_prog_type bpf_program__type(const struct bpf_program *prog);
+
+/**
+ * @brief **bpf_program__set_type()** sets the program
+ * type of the passed BPF program.
+ * @param prog BPF program to set the program type for
+ * @param type program type to set the BPF map to have
+ * @return error code; or 0 if no error. An error occurs
+ * if the object is already loaded.
+ *
+ * This must be called before the BPF object is loaded,
+ * otherwise it has no effect and an error is returned.
+ */
 LIBBPF_API int bpf_program__set_type(struct bpf_program *prog,
 				     enum bpf_prog_type type);
 
 LIBBPF_API enum bpf_attach_type
 bpf_program__expected_attach_type(const struct bpf_program *prog);
+
+/**
+ * @brief **bpf_program__set_expected_attach_type()** sets the
+ * attach type of the passed BPF program. This is used for
+ * auto-detection of attachment when programs are loaded.
+ * @param prog BPF program to set the attach type for
+ * @param type attach type to set the BPF map to have
+ * @return error code; or 0 if no error. An error occurs
+ * if the object is already loaded.
+ *
+ * This must be called before the BPF object is loaded,
+ * otherwise it has no effect and an error is returned.
+ */
 LIBBPF_API int
 bpf_program__set_expected_attach_type(struct bpf_program *prog,
 				      enum bpf_attach_type type);
@@ -707,6 +772,17 @@ LIBBPF_API int bpf_program__set_log_level(struct bpf_program *prog, __u32 log_le
 LIBBPF_API const char *bpf_program__log_buf(const struct bpf_program *prog, size_t *log_size);
 LIBBPF_API int bpf_program__set_log_buf(struct bpf_program *prog, char *log_buf, size_t log_size);
 
+/**
+ * @brief **bpf_program__set_attach_target()** sets BTF-based attach target
+ * for supported BPF program types:
+ *   - BTF-aware raw tracepoints (tp_btf);
+ *   - fentry/fexit/fmod_ret;
+ *   - lsm;
+ *   - freplace.
+ * @param prog BPF program to set the attach type for
+ * @param type attach type to set the BPF map to have
+ * @return error code; or 0 if no error occurred.
+ */
 LIBBPF_API int
 bpf_program__set_attach_target(struct bpf_program *prog, int attach_prog_fd,
 			       const char *attach_func_name);
-- 
cgit v1.2.3


From b71a2ebf74ef509b6b6926c78549e183c3b63947 Mon Sep 17 00:00:00 2001
From: Gaosheng Cui <cuigaosheng1@huawei.com>
Date: Thu, 21 Apr 2022 11:18:03 +0800
Subject: libbpf: Remove redundant non-null checks on obj_elf

Obj_elf is already non-null checked at the function entry, so remove
redundant non-null checks on obj_elf.

Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220421031803.2283974-1-cuigaosheng1@huawei.com
---
 tools/lib/bpf/libbpf.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

(limited to 'tools/lib')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 94940497354b..873a29ce7781 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1233,10 +1233,8 @@ static void bpf_object__elf_finish(struct bpf_object *obj)
 	if (!obj->efile.elf)
 		return;
 
-	if (obj->efile.elf) {
-		elf_end(obj->efile.elf);
-		obj->efile.elf = NULL;
-	}
+	elf_end(obj->efile.elf);
+	obj->efile.elf = NULL;
 	obj->efile.symbols = NULL;
 	obj->efile.st_ops_data = NULL;
 
-- 
cgit v1.2.3


From 8462e0b46fe2d4c56d0a7de705228e3bf1da03d9 Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko <andrii@kernel.org>
Date: Wed, 20 Apr 2022 20:39:44 -0700
Subject: libbpf: Teach bpf_link_create() to fallback to
 bpf_raw_tracepoint_open()

Teach bpf_link_create() to fallback to bpf_raw_tracepoint_open() on
older kernels for programs that are attachable through
BPF_RAW_TRACEPOINT_OPEN. This makes bpf_link_create() more unified and
convenient interface for creating bpf_link-based attachments.

With this approach end users can just use bpf_link_create() for
tp_btf/fentry/fexit/fmod_ret/lsm program attachments without needing to
care about kernel support, as libbpf will handle this transparently. On
the other hand, as newer features (like BPF cookie) are added to
LINK_CREATE interface, they will be readily usable though the same
bpf_link_create() API without any major refactoring from user's
standpoint.

bpf_program__attach_btf_id() is now using bpf_link_create() internally
as well and will take advantaged of this unified interface when BPF
cookie is added for fentry/fexit.

Doing proactive feature detection of LINK_CREATE support for
fentry/tp_btf/etc is quite involved. It requires parsing vmlinux BTF,
determining some stable and guaranteed to be in all kernels versions
target BTF type (either raw tracepoint or fentry target function),
actually attaching this program and thus potentially affecting the
performance of the host kernel briefly, etc. So instead we are taking
much simpler "lazy" approach of falling back to
bpf_raw_tracepoint_open() call only if initial LINK_CREATE command
fails. For modern kernels this will mean zero added overhead, while
older kernels will incur minimal overhead with a single fast-failing
LINK_CREATE call.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Kui-Feng Lee <kuifeng@fb.com>
Link: https://lore.kernel.org/bpf/20220421033945.3602803-3-andrii@kernel.org
---
 tools/lib/bpf/bpf.c    | 34 ++++++++++++++++++++++++++++++++--
 tools/lib/bpf/libbpf.c |  3 ++-
 2 files changed, 34 insertions(+), 3 deletions(-)

(limited to 'tools/lib')

diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index cf27251adb92..a9d292c106c2 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -817,7 +817,7 @@ int bpf_link_create(int prog_fd, int target_fd,
 {
 	__u32 target_btf_id, iter_info_len;
 	union bpf_attr attr;
-	int fd;
+	int fd, err;
 
 	if (!OPTS_VALID(opts, bpf_link_create_opts))
 		return libbpf_err(-EINVAL);
@@ -870,7 +870,37 @@ int bpf_link_create(int prog_fd, int target_fd,
 	}
 proceed:
 	fd = sys_bpf_fd(BPF_LINK_CREATE, &attr, sizeof(attr));
-	return libbpf_err_errno(fd);
+	if (fd >= 0)
+		return fd;
+	/* we'll get EINVAL if LINK_CREATE doesn't support attaching fentry
+	 * and other similar programs
+	 */
+	err = -errno;
+	if (err != -EINVAL)
+		return libbpf_err(err);
+
+	/* if user used features not supported by
+	 * BPF_RAW_TRACEPOINT_OPEN command, then just give up immediately
+	 */
+	if (attr.link_create.target_fd || attr.link_create.target_btf_id)
+		return libbpf_err(err);
+	if (!OPTS_ZEROED(opts, sz))
+		return libbpf_err(err);
+
+	/* otherwise, for few select kinds of programs that can be
+	 * attached using BPF_RAW_TRACEPOINT_OPEN command, try that as
+	 * a fallback for older kernels
+	 */
+	switch (attach_type) {
+	case BPF_TRACE_RAW_TP:
+	case BPF_LSM_MAC:
+	case BPF_TRACE_FENTRY:
+	case BPF_TRACE_FEXIT:
+	case BPF_MODIFY_RETURN:
+		return bpf_raw_tracepoint_open(NULL, prog_fd);
+	default:
+		return libbpf_err(err);
+	}
 }
 
 int bpf_link_detach(int link_fd)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 873a29ce7781..9a213aaaac8a 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -11260,7 +11260,8 @@ static struct bpf_link *bpf_program__attach_btf_id(const struct bpf_program *pro
 		return libbpf_err_ptr(-ENOMEM);
 	link->detach = &bpf_link__detach_fd;
 
-	pfd = bpf_raw_tracepoint_open(NULL, prog_fd);
+	/* libbpf is smart enough to redirect to BPF_RAW_TRACEPOINT_OPEN on old kernels */
+	pfd = bpf_link_create(prog_fd, 0, bpf_program__expected_attach_type(prog), NULL);
 	if (pfd < 0) {
 		pfd = -errno;
 		free(link);
-- 
cgit v1.2.3


From 003fed595c0f37d0ad112447f5f942654979426c Mon Sep 17 00:00:00 2001
From: Yuntao Wang <ytcoode@gmail.com>
Date: Sun, 24 Apr 2022 22:34:20 +0800
Subject: libbpf: Remove unnecessary type cast

The link variable is already of type 'struct bpf_link *', casting it to
'struct bpf_link *' is redundant, drop it.

Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220424143420.457082-1-ytcoode@gmail.com
---
 tools/lib/bpf/libbpf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'tools/lib')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 9a213aaaac8a..cc1a8fc47f72 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -11270,7 +11270,7 @@ static struct bpf_link *bpf_program__attach_btf_id(const struct bpf_program *pro
 		return libbpf_err_ptr(pfd);
 	}
 	link->fd = pfd;
-	return (struct bpf_link *)link;
+	return link;
 }
 
 struct bpf_link *bpf_program__attach_trace(const struct bpf_program *prog)
-- 
cgit v1.2.3


From ef89654f2bc7459f45b40be80de6cd3765ef8539 Mon Sep 17 00:00:00 2001
From: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Date: Mon, 25 Apr 2022 03:18:58 +0530
Subject: libbpf: Add kptr type tag macros to bpf_helpers.h

Include convenience definitions:
__kptr:	Unreferenced kptr
__kptr_ref: Referenced kptr

Users can use them to tag the pointer type meant to be used with the new
support directly in the map value definition.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220424214901.2743946-11-memxor@gmail.com
---
 tools/lib/bpf/bpf_helpers.h | 7 +++++++
 1 file changed, 7 insertions(+)

(limited to 'tools/lib')

diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h
index 44df982d2a5c..5de3eb267125 100644
--- a/tools/lib/bpf/bpf_helpers.h
+++ b/tools/lib/bpf/bpf_helpers.h
@@ -149,6 +149,13 @@ enum libbpf_tristate {
 
 #define __kconfig __attribute__((section(".kconfig")))
 #define __ksym __attribute__((section(".ksyms")))
+#if __has_attribute(btf_type_tag)
+#define __kptr __attribute__((btf_type_tag("kptr")))
+#define __kptr_ref __attribute__((btf_type_tag("kptr_ref")))
+#else
+#define __kptr
+#define __kptr_ref
+#endif
 
 #ifndef ___bpf_concat
 #define ___bpf_concat(a, b) a ## b
-- 
cgit v1.2.3


From afe98d46ba22316acfd198eb5cd4db2ef2d427d7 Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko <andrii@kernel.org>
Date: Mon, 25 Apr 2022 17:45:02 -0700
Subject: libbpf: Fix anonymous type check in CO-RE logic

Use type name for checking whether CO-RE relocation is referring to
anonymous type. Using spec string makes no sense.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220426004511.2691730-2-andrii@kernel.org
---
 tools/lib/bpf/relo_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'tools/lib')

diff --git a/tools/lib/bpf/relo_core.c b/tools/lib/bpf/relo_core.c
index f946f23eab20..adaa22160692 100644
--- a/tools/lib/bpf/relo_core.c
+++ b/tools/lib/bpf/relo_core.c
@@ -1207,7 +1207,7 @@ int bpf_core_calc_relo_insn(const char *prog_name,
 	}
 
 	/* libbpf doesn't support candidate search for anonymous types */
-	if (str_is_empty(spec_str)) {
+	if (str_is_empty(local_name)) {
 		pr_warn("prog '%s': relo #%d: <%s> (%d) relocation doesn't support anonymous types\n",
 			prog_name, relo_idx, core_relo_kind_str(relo->kind), relo->kind);
 		return -EOPNOTSUPP;
-- 
cgit v1.2.3


From 0994a54c5202114ad0e3b3a0f1326e810b23ad38 Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko <andrii@kernel.org>
Date: Mon, 25 Apr 2022 17:45:03 -0700
Subject: libbpf: Drop unhelpful "program too large" guess

libbpf pretends it knows actual limit of BPF program instructions based
on UAPI headers it compiled with. There is neither any guarantee that
UAPI headers match host kernel, nor BPF verifier actually uses
BPF_MAXINSNS constant anymore. Just drop unhelpful "guess", BPF verifier
will emit actual reason for failure in its logs anyways.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220426004511.2691730-3-andrii@kernel.org
---
 tools/lib/bpf/libbpf.c | 4 ----
 1 file changed, 4 deletions(-)

(limited to 'tools/lib')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index cc1a8fc47f72..b8cc862687a2 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -6828,10 +6828,6 @@ retry_load:
 		pr_warn("prog '%s': -- BEGIN PROG LOAD LOG --\n%s-- END PROG LOAD LOG --\n",
 			prog->name, log_buf);
 	}
-	if (insns_cnt >= BPF_MAXINSNS) {
-		pr_warn("prog '%s': program too large (%d insns), at most %d insns\n",
-			prog->name, insns_cnt, BPF_MAXINSNS);
-	}
 
 out:
 	if (own_log_buf)
-- 
cgit v1.2.3


From 966a7509325395c51c5f6d89e7352b0585e4804b Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko <andrii@kernel.org>
Date: Mon, 25 Apr 2022 17:45:04 -0700
Subject: libbpf: Fix logic for finding matching program for CO-RE relocation

Fix the bug in bpf_object__relocate_core() which can lead to finding
invalid matching BPF program when processing CO-RE relocation. IF
matching program is not found, last encountered program will be assumed
to be correct program and thus error detection won't detect the problem.

Fixes: 9c82a63cf370 ("libbpf: Fix CO-RE relocs against .text section")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220426004511.2691730-4-andrii@kernel.org
---
 tools/lib/bpf/libbpf.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

(limited to 'tools/lib')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index b8cc862687a2..946b4590c4d3 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -5677,9 +5677,10 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
 		 */
 		prog = NULL;
 		for (i = 0; i < obj->nr_programs; i++) {
-			prog = &obj->programs[i];
-			if (strcmp(prog->sec_name, sec_name) == 0)
+			if (strcmp(obj->programs[i].sec_name, sec_name) == 0) {
+				prog = &obj->programs[i];
 				break;
+			}
 		}
 		if (!prog) {
 			pr_warn("sec '%s': failed to find a BPF program\n", sec_name);
-- 
cgit v1.2.3


From 11d5daa89254ba2233d422777d52dbf24666b280 Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko <andrii@kernel.org>
Date: Mon, 25 Apr 2022 17:45:05 -0700
Subject: libbpf: Avoid joining .BTF.ext data with BPF programs by section name

Instead of using ELF section names as a joining key between .BTF.ext and
corresponding BPF programs, pre-build .BTF.ext section number to ELF
section index mapping during bpf_object__open() and use it later for
matching .BTF.ext information (func/line info or CO-RE relocations) to
their respective BPF programs and subprograms.

This simplifies corresponding joining logic and let's libbpf do
manipulations with BPF program's ELF sections like dropping leading '?'
character for non-autoloaded programs. Original joining logic in
bpf_object__relocate_core() (see relevant comment that's now removed)
was never elegant, so it's a good improvement regardless. But it also
avoids unnecessary internal assumptions about preserving original ELF
section name as BPF program's section name (which was broken when
SEC("?abc") support was added).

Fixes: a3820c481112 ("libbpf: Support opting out from autoloading BPF programs declaratively")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220426004511.2691730-5-andrii@kernel.org
---
 tools/lib/bpf/btf.c             |  9 +++--
 tools/lib/bpf/libbpf.c          | 78 +++++++++++++++++++++++++++--------------
 tools/lib/bpf/libbpf_internal.h |  7 ++++
 3 files changed, 65 insertions(+), 29 deletions(-)

(limited to 'tools/lib')

diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index d124e9e533f0..bb1e06eb1eca 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -2626,6 +2626,7 @@ static int btf_ext_setup_info(struct btf_ext *btf_ext,
 	const struct btf_ext_info_sec *sinfo;
 	struct btf_ext_info *ext_info;
 	__u32 info_left, record_size;
+	size_t sec_cnt = 0;
 	/* The start of the info sec (including the __u32 record_size). */
 	void *info;
 
@@ -2689,8 +2690,7 @@ static int btf_ext_setup_info(struct btf_ext *btf_ext,
 			return -EINVAL;
 		}
 
-		total_record_size = sec_hdrlen +
-				    (__u64)num_records * record_size;
+		total_record_size = sec_hdrlen + (__u64)num_records * record_size;
 		if (info_left < total_record_size) {
 			pr_debug("%s section has incorrect num_records in .BTF.ext\n",
 			     ext_sec->desc);
@@ -2699,12 +2699,14 @@ static int btf_ext_setup_info(struct btf_ext *btf_ext,
 
 		info_left -= total_record_size;
 		sinfo = (void *)sinfo + total_record_size;
+		sec_cnt++;
 	}
 
 	ext_info = ext_sec->ext_info;
 	ext_info->len = ext_sec->len - sizeof(__u32);
 	ext_info->rec_size = record_size;
 	ext_info->info = info + sizeof(__u32);
+	ext_info->sec_cnt = sec_cnt;
 
 	return 0;
 }
@@ -2788,6 +2790,9 @@ void btf_ext__free(struct btf_ext *btf_ext)
 {
 	if (IS_ERR_OR_NULL(btf_ext))
 		return;
+	free(btf_ext->func_info.sec_idxs);
+	free(btf_ext->line_info.sec_idxs);
+	free(btf_ext->core_relo_info.sec_idxs);
 	free(btf_ext->data);
 	free(btf_ext);
 }
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 946b4590c4d3..81f2b987fd77 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -2765,6 +2765,9 @@ static int bpf_object__init_btf(struct bpf_object *obj,
 		btf__set_pointer_size(obj->btf, 8);
 	}
 	if (btf_ext_data) {
+		struct btf_ext_info *ext_segs[3];
+		int seg_num, sec_num;
+
 		if (!obj->btf) {
 			pr_debug("Ignore ELF section %s because its depending ELF section %s is not found.\n",
 				 BTF_EXT_ELF_SEC, BTF_ELF_SEC);
@@ -2778,6 +2781,43 @@ static int bpf_object__init_btf(struct bpf_object *obj,
 			obj->btf_ext = NULL;
 			goto out;
 		}
+
+		/* setup .BTF.ext to ELF section mapping */
+		ext_segs[0] = &obj->btf_ext->func_info;
+		ext_segs[1] = &obj->btf_ext->line_info;
+		ext_segs[2] = &obj->btf_ext->core_relo_info;
+		for (seg_num = 0; seg_num < ARRAY_SIZE(ext_segs); seg_num++) {
+			struct btf_ext_info *seg = ext_segs[seg_num];
+			const struct btf_ext_info_sec *sec;
+			const char *sec_name;
+			Elf_Scn *scn;
+
+			if (seg->sec_cnt == 0)
+				continue;
+
+			seg->sec_idxs = calloc(seg->sec_cnt, sizeof(*seg->sec_idxs));
+			if (!seg->sec_idxs) {
+				err = -ENOMEM;
+				goto out;
+			}
+
+			sec_num = 0;
+			for_each_btf_ext_sec(seg, sec) {
+				/* preventively increment index to avoid doing
+				 * this before every continue below
+				 */
+				sec_num++;
+
+				sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off);
+				if (str_is_empty(sec_name))
+					continue;
+				scn = elf_sec_by_name(obj, sec_name);
+				if (!scn)
+					continue;
+
+				seg->sec_idxs[sec_num - 1] = elf_ndxscn(scn);
+			}
+		}
 	}
 out:
 	if (err && libbpf_needs_btf(obj)) {
@@ -5642,7 +5682,7 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
 	struct bpf_program *prog;
 	struct bpf_insn *insn;
 	const char *sec_name;
-	int i, err = 0, insn_idx, sec_idx;
+	int i, err = 0, insn_idx, sec_idx, sec_num;
 
 	if (obj->btf_ext->core_relo_info.len == 0)
 		return 0;
@@ -5663,33 +5703,18 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
 	}
 
 	seg = &obj->btf_ext->core_relo_info;
+	sec_num = 0;
 	for_each_btf_ext_sec(seg, sec) {
+		sec_idx = seg->sec_idxs[sec_num];
+		sec_num++;
+
 		sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off);
 		if (str_is_empty(sec_name)) {
 			err = -EINVAL;
 			goto out;
 		}
-		/* bpf_object's ELF is gone by now so it's not easy to find
-		 * section index by section name, but we can find *any*
-		 * bpf_program within desired section name and use it's
-		 * prog->sec_idx to do a proper search by section index and
-		 * instruction offset
-		 */
-		prog = NULL;
-		for (i = 0; i < obj->nr_programs; i++) {
-			if (strcmp(obj->programs[i].sec_name, sec_name) == 0) {
-				prog = &obj->programs[i];
-				break;
-			}
-		}
-		if (!prog) {
-			pr_warn("sec '%s': failed to find a BPF program\n", sec_name);
-			return -ENOENT;
-		}
-		sec_idx = prog->sec_idx;
 
-		pr_debug("sec '%s': found %d CO-RE relocations\n",
-			 sec_name, sec->num_info);
+		pr_debug("sec '%s': found %d CO-RE relocations\n", sec_name, sec->num_info);
 
 		for_each_btf_ext_rec(seg, sec, i, rec) {
 			if (rec->insn_off % BPF_INSN_SZ)
@@ -5873,14 +5898,13 @@ static int adjust_prog_btf_ext_info(const struct bpf_object *obj,
 	void *rec, *rec_end, *new_prog_info;
 	const struct btf_ext_info_sec *sec;
 	size_t old_sz, new_sz;
-	const char *sec_name;
-	int i, off_adj;
+	int i, sec_num, sec_idx, off_adj;
 
+	sec_num = 0;
 	for_each_btf_ext_sec(ext_info, sec) {
-		sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off);
-		if (!sec_name)
-			return -EINVAL;
-		if (strcmp(sec_name, prog->sec_name) != 0)
+		sec_idx = ext_info->sec_idxs[sec_num];
+		sec_num++;
+		if (prog->sec_idx != sec_idx)
 			continue;
 
 		for_each_btf_ext_rec(ext_info, sec, i, rec) {
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
index 054cd8e93d7c..4abdbe2fea9d 100644
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -376,6 +376,13 @@ struct btf_ext_info {
 	void *info;
 	__u32 rec_size;
 	__u32 len;
+	/* optional (maintained internally by libbpf) mapping between .BTF.ext
+	 * section and corresponding ELF section. This is used to join
+	 * information like CO-RE relocation records with corresponding BPF
+	 * programs defined in ELF sections
+	 */
+	__u32 *sec_idxs;
+	int sec_cnt;
 };
 
 #define for_each_btf_ext_sec(seg, sec)					\
-- 
cgit v1.2.3


From 185cfe837fdbb1fcc0f6b8fbcf5fdd2d1fccd3ad Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko <andrii@kernel.org>
Date: Mon, 25 Apr 2022 17:45:07 -0700
Subject: libbpf: Record subprog-resolved CO-RE relocations unconditionally

Previously, libbpf recorded CO-RE relocations with insns_idx resolved
according to finalized subprog locations (which are appended at the end
of entry BPF program) to simplify the job of light skeleton generator.

This is necessary because once subprogs' instructions are appended to
main entry BPF program all the subprog instruction indices are shifted
and that shift is different for each entry (main) BPF program, so it's
generally impossible to map final absolute insn_idx of the finalized BPF
program to their original locations inside subprograms.

This information is now going to be used not only during light skeleton
generation, but also to map absolute instruction index to subprog's
instruction and its corresponding CO-RE relocation. So start recording
these relocations always, not just when obj->gen_loader is set.

This information is going to be freed at the end of bpf_object__load()
step, as before (but this can change in the future if there will be
a need for this information post load step).

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220426004511.2691730-7-andrii@kernel.org
---
 tools/lib/bpf/libbpf.c | 27 ++++++++++++---------------
 1 file changed, 12 insertions(+), 15 deletions(-)

(limited to 'tools/lib')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 81f2b987fd77..109fc86335f6 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -5749,16 +5749,16 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
 				return -EINVAL;
 			insn = &prog->insns[insn_idx];
 
-			if (prog->obj->gen_loader) {
-				err = record_relo_core(prog, rec, insn_idx);
-				if (err) {
-					pr_warn("prog '%s': relo #%d: failed to record relocation: %d\n",
-						prog->name, i, err);
-					goto out;
-				}
-				continue;
+			err = record_relo_core(prog, rec, insn_idx);
+			if (err) {
+				pr_warn("prog '%s': relo #%d: failed to record relocation: %d\n",
+					prog->name, i, err);
+				goto out;
 			}
 
+			if (prog->obj->gen_loader)
+				continue;
+
 			err = bpf_core_resolve_relo(prog, rec, i, obj->btf, cand_cache, &targ_res);
 			if (err) {
 				pr_warn("prog '%s': relo #%d: failed to relocate: %d\n",
@@ -6299,7 +6299,6 @@ bpf_object__relocate_calls(struct bpf_object *obj, struct bpf_program *prog)
 	if (err)
 		return err;
 
-
 	return 0;
 }
 
@@ -6360,8 +6359,7 @@ bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path)
 				err);
 			return err;
 		}
-		if (obj->gen_loader)
-			bpf_object__sort_relos(obj);
+		bpf_object__sort_relos(obj);
 	}
 
 	/* Before relocating calls pre-process relocations and mark
@@ -6421,8 +6419,7 @@ bpf_object__relocate(struct bpf_object *obj, const char *targ_btf_path)
 			return err;
 		}
 	}
-	if (!obj->gen_loader)
-		bpf_object__free_relocs(obj);
+
 	return 0;
 }
 
@@ -7014,8 +7011,8 @@ bpf_object__load_progs(struct bpf_object *obj, int log_level)
 		if (err)
 			return err;
 	}
-	if (obj->gen_loader)
-		bpf_object__free_relocs(obj);
+
+	bpf_object__free_relocs(obj);
 	return 0;
 }
 
-- 
cgit v1.2.3


From b58af63aab11e4ae00fe96de9505759cfdde8ee9 Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko <andrii@kernel.org>
Date: Mon, 25 Apr 2022 17:45:08 -0700
Subject: libbpf: Refactor CO-RE relo human description formatting routine

Refactor how CO-RE relocation is formatted. Now it dumps human-readable
representation, currently used by libbpf in either debug or error
message output during CO-RE relocation resolution process, into provided
buffer. This approach allows for better reuse of this functionality
outside of CO-RE relocation resolution, which we'll use in next patch
for providing better error message for BPF verifier rejecting BPF
program due to unguarded failed CO-RE relocation.

It also gets rid of annoying "stitching" of libbpf_print() calls, which
was the only place where we did this.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220426004511.2691730-8-andrii@kernel.org
---
 tools/lib/bpf/relo_core.c | 64 ++++++++++++++++++++++++++++-------------------
 1 file changed, 38 insertions(+), 26 deletions(-)

(limited to 'tools/lib')

diff --git a/tools/lib/bpf/relo_core.c b/tools/lib/bpf/relo_core.c
index adaa22160692..13d36a705464 100644
--- a/tools/lib/bpf/relo_core.c
+++ b/tools/lib/bpf/relo_core.c
@@ -1055,51 +1055,66 @@ poison:
  * [<type-id>] (<type-name>) + <raw-spec> => <offset>@<spec>,
  * where <spec> is a C-syntax view of recorded field access, e.g.: x.a[3].b
  */
-static void bpf_core_dump_spec(const char *prog_name, int level, const struct bpf_core_spec *spec)
+static int bpf_core_format_spec(char *buf, size_t buf_sz, const struct bpf_core_spec *spec)
 {
 	const struct btf_type *t;
 	const struct btf_enum *e;
 	const char *s;
 	__u32 type_id;
-	int i;
+	int i, len = 0;
+
+#define append_buf(fmt, args...)				\
+	({							\
+		int r;						\
+		r = snprintf(buf, buf_sz, fmt, ##args);		\
+		len += r;					\
+		if (r >= buf_sz)				\
+			r = buf_sz;				\
+		buf += r;					\
+		buf_sz -= r;					\
+	})
 
 	type_id = spec->root_type_id;
 	t = btf_type_by_id(spec->btf, type_id);
 	s = btf__name_by_offset(spec->btf, t->name_off);
 
-	libbpf_print(level, "[%u] %s %s", type_id, btf_kind_str(t), str_is_empty(s) ? "<anon>" : s);
+	append_buf("<%s> [%u] %s %s",
+		   core_relo_kind_str(spec->relo_kind),
+		   type_id, btf_kind_str(t), str_is_empty(s) ? "<anon>" : s);
 
 	if (core_relo_is_type_based(spec->relo_kind))
-		return;
+		return len;
 
 	if (core_relo_is_enumval_based(spec->relo_kind)) {
 		t = skip_mods_and_typedefs(spec->btf, type_id, NULL);
 		e = btf_enum(t) + spec->raw_spec[0];
 		s = btf__name_by_offset(spec->btf, e->name_off);
 
-		libbpf_print(level, "::%s = %u", s, e->val);
-		return;
+		append_buf("::%s = %u", s, e->val);
+		return len;
 	}
 
 	if (core_relo_is_field_based(spec->relo_kind)) {
 		for (i = 0; i < spec->len; i++) {
 			if (spec->spec[i].name)
-				libbpf_print(level, ".%s", spec->spec[i].name);
+				append_buf(".%s", spec->spec[i].name);
 			else if (i > 0 || spec->spec[i].idx > 0)
-				libbpf_print(level, "[%u]", spec->spec[i].idx);
+				append_buf("[%u]", spec->spec[i].idx);
 		}
 
-		libbpf_print(level, " (");
+		append_buf(" (");
 		for (i = 0; i < spec->raw_len; i++)
-			libbpf_print(level, "%s%d", i == 0 ? "" : ":", spec->raw_spec[i]);
+			append_buf("%s%d", i == 0 ? "" : ":", spec->raw_spec[i]);
 
 		if (spec->bit_offset % 8)
-			libbpf_print(level, " @ offset %u.%u)",
-				     spec->bit_offset / 8, spec->bit_offset % 8);
+			append_buf(" @ offset %u.%u)", spec->bit_offset / 8, spec->bit_offset % 8);
 		else
-			libbpf_print(level, " @ offset %u)", spec->bit_offset / 8);
-		return;
+			append_buf(" @ offset %u)", spec->bit_offset / 8);
+		return len;
 	}
+
+	return len;
+#undef append_buf
 }
 
 /*
@@ -1168,6 +1183,7 @@ int bpf_core_calc_relo_insn(const char *prog_name,
 	const char *local_name;
 	__u32 local_id;
 	const char *spec_str;
+	char spec_buf[256];
 	int i, j, err;
 
 	local_id = relo->type_id;
@@ -1190,10 +1206,8 @@ int bpf_core_calc_relo_insn(const char *prog_name,
 		return -EINVAL;
 	}
 
-	pr_debug("prog '%s': relo #%d: kind <%s> (%d), spec is ", prog_name,
-		 relo_idx, core_relo_kind_str(relo->kind), relo->kind);
-	bpf_core_dump_spec(prog_name, LIBBPF_DEBUG, local_spec);
-	libbpf_print(LIBBPF_DEBUG, "\n");
+	bpf_core_format_spec(spec_buf, sizeof(spec_buf), local_spec);
+	pr_debug("prog '%s': relo #%d: %s\n", prog_name, relo_idx, spec_buf);
 
 	/* TYPE_ID_LOCAL relo is special and doesn't need candidate search */
 	if (relo->kind == BPF_CORE_TYPE_ID_LOCAL) {
@@ -1217,17 +1231,15 @@ int bpf_core_calc_relo_insn(const char *prog_name,
 		err = bpf_core_spec_match(local_spec, cands->cands[i].btf,
 					  cands->cands[i].id, cand_spec);
 		if (err < 0) {
-			pr_warn("prog '%s': relo #%d: error matching candidate #%d ",
-				prog_name, relo_idx, i);
-			bpf_core_dump_spec(prog_name, LIBBPF_WARN, cand_spec);
-			libbpf_print(LIBBPF_WARN, ": %d\n", err);
+			bpf_core_format_spec(spec_buf, sizeof(spec_buf), cand_spec);
+			pr_warn("prog '%s': relo #%d: error matching candidate #%d %s: %d\n ",
+				prog_name, relo_idx, i, spec_buf, err);
 			return err;
 		}
 
-		pr_debug("prog '%s': relo #%d: %s candidate #%d ", prog_name,
-			 relo_idx, err == 0 ? "non-matching" : "matching", i);
-		bpf_core_dump_spec(prog_name, LIBBPF_DEBUG, cand_spec);
-		libbpf_print(LIBBPF_DEBUG, "\n");
+		bpf_core_format_spec(spec_buf, sizeof(spec_buf), cand_spec);
+		pr_debug("prog '%s': relo #%d: %s candidate #%d %s\n", prog_name,
+			 relo_idx, err == 0 ? "non-matching" : "matching", i, spec_buf);
 
 		if (err == 0)
 			continue;
-- 
cgit v1.2.3


From 14032f2644534ecd5693ebfeef44cbf0d989a7fe Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko <andrii@kernel.org>
Date: Mon, 25 Apr 2022 17:45:09 -0700
Subject: libbpf: Simplify bpf_core_parse_spec() signature

Simplify bpf_core_parse_spec() signature to take struct bpf_core_relo as
an input instead of requiring callers to decompose them into type_id,
relo, spec_str, etc. This makes using and reusing this helper easier.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220426004511.2691730-9-andrii@kernel.org
---
 tools/lib/bpf/relo_core.c | 34 +++++++++++++++-------------------
 1 file changed, 15 insertions(+), 19 deletions(-)

(limited to 'tools/lib')

diff --git a/tools/lib/bpf/relo_core.c b/tools/lib/bpf/relo_core.c
index 13d36a705464..4a9ad0cfb474 100644
--- a/tools/lib/bpf/relo_core.c
+++ b/tools/lib/bpf/relo_core.c
@@ -179,28 +179,27 @@ static bool core_relo_is_enumval_based(enum bpf_core_relo_kind kind)
  * string to specify enumerator's value index that need to be relocated.
  */
 static int bpf_core_parse_spec(const char *prog_name, const struct btf *btf,
-			       __u32 type_id,
-			       const char *spec_str,
-			       enum bpf_core_relo_kind relo_kind,
+			       const struct bpf_core_relo *relo,
 			       struct bpf_core_spec *spec)
 {
 	int access_idx, parsed_len, i;
 	struct bpf_core_accessor *acc;
 	const struct btf_type *t;
-	const char *name;
+	const char *name, *spec_str;
 	__u32 id;
 	__s64 sz;
 
+	spec_str = btf__name_by_offset(btf, relo->access_str_off);
 	if (str_is_empty(spec_str) || *spec_str == ':')
 		return -EINVAL;
 
 	memset(spec, 0, sizeof(*spec));
 	spec->btf = btf;
-	spec->root_type_id = type_id;
-	spec->relo_kind = relo_kind;
+	spec->root_type_id = relo->type_id;
+	spec->relo_kind = relo->kind;
 
 	/* type-based relocations don't have a field access string */
-	if (core_relo_is_type_based(relo_kind)) {
+	if (core_relo_is_type_based(relo->kind)) {
 		if (strcmp(spec_str, "0"))
 			return -EINVAL;
 		return 0;
@@ -221,7 +220,7 @@ static int bpf_core_parse_spec(const char *prog_name, const struct btf *btf,
 	if (spec->raw_len == 0)
 		return -EINVAL;
 
-	t = skip_mods_and_typedefs(btf, type_id, &id);
+	t = skip_mods_and_typedefs(btf, relo->type_id, &id);
 	if (!t)
 		return -EINVAL;
 
@@ -231,7 +230,7 @@ static int bpf_core_parse_spec(const char *prog_name, const struct btf *btf,
 	acc->idx = access_idx;
 	spec->len++;
 
-	if (core_relo_is_enumval_based(relo_kind)) {
+	if (core_relo_is_enumval_based(relo->kind)) {
 		if (!btf_is_enum(t) || spec->raw_len > 1 || access_idx >= btf_vlen(t))
 			return -EINVAL;
 
@@ -240,7 +239,7 @@ static int bpf_core_parse_spec(const char *prog_name, const struct btf *btf,
 		return 0;
 	}
 
-	if (!core_relo_is_field_based(relo_kind))
+	if (!core_relo_is_field_based(relo->kind))
 		return -EINVAL;
 
 	sz = btf__resolve_size(btf, id);
@@ -301,7 +300,7 @@ static int bpf_core_parse_spec(const char *prog_name, const struct btf *btf,
 			spec->bit_offset += access_idx * sz * 8;
 		} else {
 			pr_warn("prog '%s': relo for [%u] %s (at idx %d) captures type [%d] of unexpected kind %s\n",
-				prog_name, type_id, spec_str, i, id, btf_kind_str(t));
+				prog_name, relo->type_id, spec_str, i, id, btf_kind_str(t));
 			return -EINVAL;
 		}
 	}
@@ -1182,7 +1181,6 @@ int bpf_core_calc_relo_insn(const char *prog_name,
 	const struct btf_type *local_type;
 	const char *local_name;
 	__u32 local_id;
-	const char *spec_str;
 	char spec_buf[256];
 	int i, j, err;
 
@@ -1192,17 +1190,15 @@ int bpf_core_calc_relo_insn(const char *prog_name,
 	if (!local_name)
 		return -EINVAL;
 
-	spec_str = btf__name_by_offset(local_btf, relo->access_str_off);
-	if (str_is_empty(spec_str))
-		return -EINVAL;
-
-	err = bpf_core_parse_spec(prog_name, local_btf, local_id, spec_str,
-				  relo->kind, local_spec);
+	err = bpf_core_parse_spec(prog_name, local_btf, relo, local_spec);
 	if (err) {
+		const char *spec_str;
+
+		spec_str = btf__name_by_offset(local_btf, relo->access_str_off);
 		pr_warn("prog '%s': relo #%d: parsing [%d] %s %s + %s failed: %d\n",
 			prog_name, relo_idx, local_id, btf_kind_str(local_type),
 			str_is_empty(local_name) ? "<anon>" : local_name,
-			spec_str, err);
+			spec_str ?: "<?>", err);
 		return -EINVAL;
 	}
 
-- 
cgit v1.2.3


From 9fdc4273b8dad70dbf8f7fc1b94eadc1c1f6c934 Mon Sep 17 00:00:00 2001
From: Andrii Nakryiko <andrii@kernel.org>
Date: Mon, 25 Apr 2022 17:45:10 -0700
Subject: libbpf: Fix up verifier log for unguarded failed CO-RE relos

Teach libbpf to post-process BPF verifier log on BPF program load
failure and detect known error patterns to provide user with more
context.

Currently there is one such common situation: an "unguarded" failed BPF
CO-RE relocation. While failing CO-RE relocation is expected, it is
expected to be property guarded in BPF code such that BPF verifier
always eliminates BPF instructions corresponding to such failed CO-RE
relos as dead code. In cases when user failed to take such precautions,
BPF verifier provides the best log it can:

  123: (85) call unknown#195896080
  invalid func unknown#195896080

Such incomprehensible log error is due to libbpf "poisoning" BPF
instruction that corresponds to failed CO-RE relocation by replacing it
with invalid `call 0xbad2310` instruction (195896080 == 0xbad2310 reads
"bad relo" if you squint hard enough).

Luckily, libbpf has all the necessary information to look up CO-RE
relocation that failed and provide more human-readable description of
what's going on:

  5: <invalid CO-RE relocation>
  failed to resolve CO-RE relocation <byte_off> [6] struct task_struct___bad.fake_field_subprog (0:2 @ offset 8)

This hopefully makes it much easier to understand what's wrong with
user's BPF program without googling magic constants.

This BPF verifier log fixup is setup to be extensible and is going to be
used for at least one other upcoming feature of libbpf in follow up patches.
Libbpf is parsing lines of BPF verifier log starting from the very end.
Currently it processes up to 10 lines of code looking for familiar
patterns. This avoids wasting lots of CPU processing huge verifier logs
(especially for log_level=2 verbosity level). Actual verification error
should normally be found in last few lines, so this should work
reliably.

If libbpf needs to expand log beyond available log_buf_size, it
truncates the end of the verifier log. Given verifier log normally ends
with something like:

  processed 2 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0

... truncating this on program load error isn't too bad (end user can
always increase log size, if it needs to get complete log).

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220426004511.2691730-10-andrii@kernel.org
---
 tools/lib/bpf/libbpf.c    | 144 ++++++++++++++++++++++++++++++++++++++++++++++
 tools/lib/bpf/relo_core.c |   8 +--
 tools/lib/bpf/relo_core.h |   6 ++
 3 files changed, 154 insertions(+), 4 deletions(-)

(limited to 'tools/lib')

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 109fc86335f6..73a5192defb3 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -5626,6 +5626,22 @@ static int record_relo_core(struct bpf_program *prog,
 	return 0;
 }
 
+static const struct bpf_core_relo *find_relo_core(struct bpf_program *prog, int insn_idx)
+{
+	struct reloc_desc *relo;
+	int i;
+
+	for (i = 0; i < prog->nr_reloc; i++) {
+		relo = &prog->reloc_desc[i];
+		if (relo->type != RELO_CORE || relo->insn_idx != insn_idx)
+			continue;
+
+		return relo->core_relo;
+	}
+
+	return NULL;
+}
+
 static int bpf_core_resolve_relo(struct bpf_program *prog,
 				 const struct bpf_core_relo *relo,
 				 int relo_idx,
@@ -6696,6 +6712,8 @@ static int libbpf_prepare_prog_load(struct bpf_program *prog,
 	return 0;
 }
 
+static void fixup_verifier_log(struct bpf_program *prog, char *buf, size_t buf_sz);
+
 static int bpf_object_load_prog_instance(struct bpf_object *obj, struct bpf_program *prog,
 					 struct bpf_insn *insns, int insns_cnt,
 					 const char *license, __u32 kern_version,
@@ -6842,6 +6860,10 @@ retry_load:
 		goto retry_load;
 
 	ret = -errno;
+
+	/* post-process verifier log to improve error descriptions */
+	fixup_verifier_log(prog, log_buf, log_buf_size);
+
 	cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
 	pr_warn("prog '%s': BPF program load failed: %s\n", prog->name, cp);
 	pr_perm_msg(ret);
@@ -6857,6 +6879,128 @@ out:
 	return ret;
 }
 
+static char *find_prev_line(char *buf, char *cur)
+{
+	char *p;
+
+	if (cur == buf) /* end of a log buf */
+		return NULL;
+
+	p = cur - 1;
+	while (p - 1 >= buf && *(p - 1) != '\n')
+		p--;
+
+	return p;
+}
+
+static void patch_log(char *buf, size_t buf_sz, size_t log_sz,
+		      char *orig, size_t orig_sz, const char *patch)
+{
+	/* size of the remaining log content to the right from the to-be-replaced part */
+	size_t rem_sz = (buf + log_sz) - (orig + orig_sz);
+	size_t patch_sz = strlen(patch);
+
+	if (patch_sz != orig_sz) {
+		/* If patch line(s) are longer than original piece of verifier log,
+		 * shift log contents by (patch_sz - orig_sz) bytes to the right
+		 * starting from after to-be-replaced part of the log.
+		 *
+		 * If patch line(s) are shorter than original piece of verifier log,
+		 * shift log contents by (orig_sz - patch_sz) bytes to the left
+		 * starting from after to-be-replaced part of the log
+		 *
+		 * We need to be careful about not overflowing available
+		 * buf_sz capacity. If that's the case, we'll truncate the end
+		 * of the original log, as necessary.
+		 */
+		if (patch_sz > orig_sz) {
+			if (orig + patch_sz >= buf + buf_sz) {
+				/* patch is big enough to cover remaining space completely */
+				patch_sz -= (orig + patch_sz) - (buf + buf_sz) + 1;
+				rem_sz = 0;
+			} else if (patch_sz - orig_sz > buf_sz - log_sz) {
+				/* patch causes part of remaining log to be truncated */
+				rem_sz -= (patch_sz - orig_sz) - (buf_sz - log_sz);
+			}
+		}
+		/* shift remaining log to the right by calculated amount */
+		memmove(orig + patch_sz, orig + orig_sz, rem_sz);
+	}
+
+	memcpy(orig, patch, patch_sz);
+}
+
+static void fixup_log_failed_core_relo(struct bpf_program *prog,
+				       char *buf, size_t buf_sz, size_t log_sz,
+				       char *line1, char *line2, char *line3)
+{
+	/* Expected log for failed and not properly guarded CO-RE relocation:
+	 * line1 -> 123: (85) call unknown#195896080
+	 * line2 -> invalid func unknown#195896080
+	 * line3 -> <anything else or end of buffer>
+	 *
+	 * "123" is the index of the instruction that was poisoned. We extract
+	 * instruction index to find corresponding CO-RE relocation and
+	 * replace this part of the log with more relevant information about
+	 * failed CO-RE relocation.
+	 */
+	const struct bpf_core_relo *relo;
+	struct bpf_core_spec spec;
+	char patch[512], spec_buf[256];
+	int insn_idx, err;
+
+	if (sscanf(line1, "%d: (%*d) call unknown#195896080\n", &insn_idx) != 1)
+		return;
+
+	relo = find_relo_core(prog, insn_idx);
+	if (!relo)
+		return;
+
+	err = bpf_core_parse_spec(prog->name, prog->obj->btf, relo, &spec);
+	if (err)
+		return;
+
+	bpf_core_format_spec(spec_buf, sizeof(spec_buf), &spec);
+	snprintf(patch, sizeof(patch),
+		 "%d: <invalid CO-RE relocation>\n"
+		 "failed to resolve CO-RE relocation %s\n",
+		 insn_idx, spec_buf);
+
+	patch_log(buf, buf_sz, log_sz, line1, line3 - line1, patch);
+}
+
+static void fixup_verifier_log(struct bpf_program *prog, char *buf, size_t buf_sz)
+{
+	/* look for familiar error patterns in last N lines of the log */
+	const size_t max_last_line_cnt = 10;
+	char *prev_line, *cur_line, *next_line;
+	size_t log_sz;
+	int i;
+
+	if (!buf)
+		return;
+
+	log_sz = strlen(buf) + 1;
+	next_line = buf + log_sz - 1;
+
+	for (i = 0; i < max_last_line_cnt; i++, next_line = cur_line) {
+		cur_line = find_prev_line(buf, next_line);
+		if (!cur_line)
+			return;
+
+		/* failed CO-RE relocation case */
+		if (str_has_pfx(cur_line, "invalid func unknown#195896080\n")) {
+			prev_line = find_prev_line(buf, cur_line);
+			if (!prev_line)
+				continue;
+
+			fixup_log_failed_core_relo(prog, buf, buf_sz, log_sz,
+						   prev_line, cur_line, next_line);
+			return;
+		}
+	}
+}
+
 static int bpf_program_record_relos(struct bpf_program *prog)
 {
 	struct bpf_object *obj = prog->obj;
diff --git a/tools/lib/bpf/relo_core.c b/tools/lib/bpf/relo_core.c
index 4a9ad0cfb474..ba4453dfd1ed 100644
--- a/tools/lib/bpf/relo_core.c
+++ b/tools/lib/bpf/relo_core.c
@@ -178,9 +178,9 @@ static bool core_relo_is_enumval_based(enum bpf_core_relo_kind kind)
  * Enum value-based relocations (ENUMVAL_EXISTS/ENUMVAL_VALUE) use access
  * string to specify enumerator's value index that need to be relocated.
  */
-static int bpf_core_parse_spec(const char *prog_name, const struct btf *btf,
-			       const struct bpf_core_relo *relo,
-			       struct bpf_core_spec *spec)
+int bpf_core_parse_spec(const char *prog_name, const struct btf *btf,
+			const struct bpf_core_relo *relo,
+			struct bpf_core_spec *spec)
 {
 	int access_idx, parsed_len, i;
 	struct bpf_core_accessor *acc;
@@ -1054,7 +1054,7 @@ poison:
  * [<type-id>] (<type-name>) + <raw-spec> => <offset>@<spec>,
  * where <spec> is a C-syntax view of recorded field access, e.g.: x.a[3].b
  */
-static int bpf_core_format_spec(char *buf, size_t buf_sz, const struct bpf_core_spec *spec)
+int bpf_core_format_spec(char *buf, size_t buf_sz, const struct bpf_core_spec *spec)
 {
 	const struct btf_type *t;
 	const struct btf_enum *e;
diff --git a/tools/lib/bpf/relo_core.h b/tools/lib/bpf/relo_core.h
index a28bf3711ce2..073039d8ca4f 100644
--- a/tools/lib/bpf/relo_core.h
+++ b/tools/lib/bpf/relo_core.h
@@ -84,4 +84,10 @@ int bpf_core_patch_insn(const char *prog_name, struct bpf_insn *insn,
 			int insn_idx, const struct bpf_core_relo *relo,
 			int relo_idx, const struct bpf_core_relo_res *res);
 
+int bpf_core_parse_spec(const char *prog_name, const struct btf *btf,
+		        const struct bpf_core_relo *relo,
+		        struct bpf_core_spec *spec);
+
+int bpf_core_format_spec(char *buf, size_t buf_sz, const struct bpf_core_spec *spec);
+
 #endif
-- 
cgit v1.2.3