[PATCH v2 bpf-next 0/2] Support riscv libbpf USDT arg parsing logic

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* [PATCH v2 bpf-next 0/2] Support riscv libbpf USDT arg parsing logic
@ 2022-04-19 14:52 Pu Lehui
  2022-04-19 14:52 ` [PATCH v2 bpf-next 1/2] libbpf: Fix usdt_cookie being cast to 32 bits Pu Lehui
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Pu Lehui @ 2022-04-19 14:52 UTC (permalink / raw)
  To: bpf, linux-kernel, netdev, linux-riscv
  Cc: andrii, ast, daniel, kafai, songliubraving, yhs, john.fastabend,
	kpsingh, paul.walmsley, palmer, aou, pulehui

patch 1 fix a minor issue where usdt_cookie is cast to 32 bits.
patch 2 add support riscv libbpf USDT argument parsing logic,
both RV32 and RV64 tests have been passed as like follow:

# ./test_progs -t usdt
#169 usdt:OK
Summary: 1/4 PASSED, 0 SKIPPED, 0 FAILED

Pu Lehui (2):
  libbpf: Fix usdt_cookie being cast to 32 bits
  libbpf: Support riscv USDT argument parsing logic

 tools/lib/bpf/libbpf.c          |   2 +-
 tools/lib/bpf/libbpf_internal.h |   2 +-
 tools/lib/bpf/usdt.c            | 115 ++++++++++++++++++++++++++++++--
 3 files changed, 113 insertions(+), 6 deletions(-)

-- 
2.25.1


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^ permalink raw reply	[flat|nested] 4+ messages in thread

* [PATCH v2 bpf-next 1/2] libbpf: Fix usdt_cookie being cast to 32 bits
  2022-04-19 14:52 [PATCH v2 bpf-next 0/2] Support riscv libbpf USDT arg parsing logic Pu Lehui
@ 2022-04-19 14:52 ` Pu Lehui
  2022-04-19 14:52 ` [PATCH v2 bpf-next 2/2] libbpf: Support riscv USDT argument parsing logic Pu Lehui
  2022-04-20  5:50 ` [PATCH v2 bpf-next 0/2] Support riscv libbpf USDT arg " patchwork-bot+netdevbpf
  2 siblings, 0 replies; 4+ messages in thread
From: Pu Lehui @ 2022-04-19 14:52 UTC (permalink / raw)
  To: bpf, linux-kernel, netdev, linux-riscv
  Cc: andrii, ast, daniel, kafai, songliubraving, yhs, john.fastabend,
	kpsingh, paul.walmsley, palmer, aou, pulehui

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>
---
 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(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index bf4f7ac54..33d21ed7c 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -10982,7 +10982,7 @@ 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 080272421..054cd8e93 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 934c25301..8e77a7260 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;
-- 
2.25.1


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^ permalink raw reply related	[flat|nested] 4+ messages in thread

* [PATCH v2 bpf-next 2/2] libbpf: Support riscv USDT argument parsing logic
  2022-04-19 14:52 [PATCH v2 bpf-next 0/2] Support riscv libbpf USDT arg parsing logic Pu Lehui
  2022-04-19 14:52 ` [PATCH v2 bpf-next 1/2] libbpf: Fix usdt_cookie being cast to 32 bits Pu Lehui
@ 2022-04-19 14:52 ` Pu Lehui
  2022-04-20  5:50 ` [PATCH v2 bpf-next 0/2] Support riscv libbpf USDT arg " patchwork-bot+netdevbpf
  2 siblings, 0 replies; 4+ messages in thread
From: Pu Lehui @ 2022-04-19 14:52 UTC (permalink / raw)
  To: bpf, linux-kernel, netdev, linux-riscv
  Cc: andrii, ast, daniel, kafai, songliubraving, yhs, john.fastabend,
	kpsingh, paul.walmsley, palmer, aou, pulehui

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>
---
v1-v2:
 - Add brief test results.
 - Make reg_map more intuitive.
 tools/lib/bpf/usdt.c | 107 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 107 insertions(+)

diff --git a/tools/lib/bpf/usdt.c b/tools/lib/bpf/usdt.c
index 8e77a7260..f1c9339cf 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)
-- 
2.25.1


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^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [PATCH v2 bpf-next 0/2] Support riscv libbpf USDT arg parsing logic
  2022-04-19 14:52 [PATCH v2 bpf-next 0/2] Support riscv libbpf USDT arg parsing logic Pu Lehui
  2022-04-19 14:52 ` [PATCH v2 bpf-next 1/2] libbpf: Fix usdt_cookie being cast to 32 bits Pu Lehui
  2022-04-19 14:52 ` [PATCH v2 bpf-next 2/2] libbpf: Support riscv USDT argument parsing logic Pu Lehui
@ 2022-04-20  5:50 ` patchwork-bot+netdevbpf
  2 siblings, 0 replies; 4+ messages in thread
From: patchwork-bot+netdevbpf @ 2022-04-20  5:50 UTC (permalink / raw)
  To: Pu Lehui
  Cc: bpf, linux-kernel, netdev, linux-riscv, andrii, ast, daniel,
	kafai, songliubraving, yhs, john.fastabend, kpsingh,
	paul.walmsley, palmer, aou

Hello:

This series was applied to bpf/bpf-next.git (master)
by Andrii Nakryiko <andrii@kernel.org>:

On Tue, 19 Apr 2022 22:52:36 +0800 you wrote:
> patch 1 fix a minor issue where usdt_cookie is cast to 32 bits.
> patch 2 add support riscv libbpf USDT argument parsing logic,
> both RV32 and RV64 tests have been passed as like follow:
> 
> # ./test_progs -t usdt
> #169 usdt:OK
> Summary: 1/4 PASSED, 0 SKIPPED, 0 FAILED
> 
> [...]

Here is the summary with links:
  - [v2,bpf-next,1/2] libbpf: Fix usdt_cookie being cast to 32 bits
    https://git.kernel.org/bpf/bpf-next/c/5af25a410acb
  - [v2,bpf-next,2/2] libbpf: Support riscv USDT argument parsing logic
    https://git.kernel.org/bpf/bpf-next/c/58ca8b0572cd

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html



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2022-04-19 14:52 [PATCH v2 bpf-next 0/2] Support riscv libbpf USDT arg parsing logic Pu Lehui
2022-04-19 14:52 ` [PATCH v2 bpf-next 1/2] libbpf: Fix usdt_cookie being cast to 32 bits Pu Lehui
2022-04-19 14:52 ` [PATCH v2 bpf-next 2/2] libbpf: Support riscv USDT argument parsing logic Pu Lehui
2022-04-20  5:50 ` [PATCH v2 bpf-next 0/2] Support riscv libbpf USDT arg " patchwork-bot+netdevbpf

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