Commit d1d51a62 authored by Andrii Nakryiko's avatar Andrii Nakryiko
Browse files

Merge branch 'libbpf: usdt arm arg parsing support' 



Puranjay Mohan says:

====================

This series add the support of the ARM architecture to libbpf USDT. This
involves implementing the parse_usdt_arg() function for ARM.

It was seen that the last part of parse_usdt_arg() is repeated for all architectures,
so, the first patch in this series refactors these functions and moved the post
processing to parse_usdt_spec()

Changes in V2[1] to V3:

- Use a tabular approach to find register offsets.
- Add the patch for refactoring parse_usdt_arg()
====================

Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
parents 3ecde218 720d93b6

tools/lib/bpf/usdt.c

+118 −78
Original line number Diff line number Diff line
@@ -1141,12 +1141,13 @@ static int parse_usdt_note(Elf *elf, const char *path, GElf_Nhdr *nhdr, 
	return 0;

}



static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg);

static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg, int *arg_sz);



static int parse_usdt_spec(struct usdt_spec *spec, const struct usdt_note *note, __u64 usdt_cookie)

{

	struct usdt_arg_spec *arg;

	const char *s;

	int len;

	int arg_sz, len;



	spec->usdt_cookie = usdt_cookie;

	spec->arg_cnt = 0;
@@ -1159,10 +1160,25 @@ static int parse_usdt_spec(struct usdt_spec *spec, const struct usdt_note *note, 
			return -E2BIG;

		}



		len = parse_usdt_arg(s, spec->arg_cnt, &spec->args[spec->arg_cnt]);

		arg = &spec->args[spec->arg_cnt];

		len = parse_usdt_arg(s, spec->arg_cnt, arg, &arg_sz);

		if (len < 0)

			return len;



		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",

				spec->arg_cnt, s, arg_sz);

			return -EINVAL;

		}



		s += len;

		spec->arg_cnt++;

	}
@@ -1219,13 +1235,13 @@ static int calc_pt_regs_off(const char *reg_name) 
	return -ENOENT;

}



static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg)

static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg, int *arg_sz)

{

	char reg_name[16];

	int arg_sz, len, reg_off;

	int len, reg_off;

	long off;



	if (sscanf(arg_str, " %d @ %ld ( %%%15[^)] ) %n", &arg_sz, &off, reg_name, &len) == 3) {

	if (sscanf(arg_str, " %d @ %ld ( %%%15[^)] ) %n", arg_sz, &off, reg_name, &len) == 3) {

		/* Memory dereference case, e.g., -4@-20(%rbp) */

		arg->arg_type = USDT_ARG_REG_DEREF;

		arg->val_off = off;
@@ -1233,7 +1249,7 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec 
		if (reg_off < 0)

			return reg_off;

		arg->reg_off = reg_off;

	} else if (sscanf(arg_str, " %d @ ( %%%15[^)] ) %n", &arg_sz, reg_name, &len) == 2) {

	} else if (sscanf(arg_str, " %d @ ( %%%15[^)] ) %n", arg_sz, reg_name, &len) == 2) {

		/* Memory dereference case without offset, e.g., 8@(%rsp) */

		arg->arg_type = USDT_ARG_REG_DEREF;

		arg->val_off = 0;
@@ -1241,7 +1257,7 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec 
		if (reg_off < 0)

			return reg_off;

		arg->reg_off = reg_off;

	} else if (sscanf(arg_str, " %d @ %%%15s %n", &arg_sz, reg_name, &len) == 2) {

	} else if (sscanf(arg_str, " %d @ %%%15s %n", arg_sz, reg_name, &len) == 2) {

		/* Register read case, e.g., -4@%eax */

		arg->arg_type = USDT_ARG_REG;

		arg->val_off = 0;
@@ -1250,7 +1266,7 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec 
		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) {

	} else if (sscanf(arg_str, " %d @ $%ld %n", arg_sz, &off, &len) == 2) {

		/* Constant value case, e.g., 4@$71 */

		arg->arg_type = USDT_ARG_CONST;

		arg->val_off = off;
@@ -1260,20 +1276,6 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec 
		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;

}
@@ -1281,13 +1283,13 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec 


/* Do not support __s390__ for now, since user_pt_regs is broken with -m31. */



static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg)

static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg, int *arg_sz)

{

	unsigned int reg;

	int arg_sz, len;

	int len;

	long off;



	if (sscanf(arg_str, " %d @ %ld ( %%r%u ) %n", &arg_sz, &off, &reg, &len) == 3) {

	if (sscanf(arg_str, " %d @ %ld ( %%r%u ) %n", arg_sz, &off, &reg, &len) == 3) {

		/* Memory dereference case, e.g., -2@-28(%r15) */

		arg->arg_type = USDT_ARG_REG_DEREF;

		arg->val_off = off;
@@ -1296,7 +1298,7 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec 
			return -EINVAL;

		}

		arg->reg_off = offsetof(user_pt_regs, gprs[reg]);

	} else if (sscanf(arg_str, " %d @ %%r%u %n", &arg_sz, &reg, &len) == 2) {

	} else if (sscanf(arg_str, " %d @ %%r%u %n", arg_sz, &reg, &len) == 2) {

		/* Register read case, e.g., -8@%r0 */

		arg->arg_type = USDT_ARG_REG;

		arg->val_off = 0;
@@ -1305,7 +1307,7 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec 
			return -EINVAL;

		}

		arg->reg_off = offsetof(user_pt_regs, gprs[reg]);

	} else if (sscanf(arg_str, " %d @ %ld %n", &arg_sz, &off, &len) == 2) {

	} else if (sscanf(arg_str, " %d @ %ld %n", arg_sz, &off, &len) == 2) {

		/* Constant value case, e.g., 4@71 */

		arg->arg_type = USDT_ARG_CONST;

		arg->val_off = off;
@@ -1315,20 +1317,6 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec 
		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;

}
@@ -1348,13 +1336,13 @@ static int calc_pt_regs_off(const char *reg_name) 
	return -ENOENT;

}



static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg)

static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg, int *arg_sz)

{

	char reg_name[16];

	int arg_sz, len, reg_off;

	int len, reg_off;

	long off;



	if (sscanf(arg_str, " %d @ \[ %15[a-z0-9], %ld ] %n", &arg_sz, reg_name, &off, &len) == 3) {

	if (sscanf(arg_str, " %d @ \[ %15[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;
@@ -1362,7 +1350,7 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec 
		if (reg_off < 0)

			return reg_off;

		arg->reg_off = reg_off;

	} else if (sscanf(arg_str, " %d @ \[ %15[a-z0-9] ] %n", &arg_sz, reg_name, &len) == 2) {

	} else if (sscanf(arg_str, " %d @ \[ %15[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;
@@ -1370,12 +1358,12 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec 
		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) {

	} 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 @ %15[a-z0-9] %n", &arg_sz, reg_name, &len) == 2) {

	} else if (sscanf(arg_str, " %d @ %15[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;
@@ -1388,20 +1376,6 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec 
		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;

}
@@ -1456,13 +1430,13 @@ static int calc_pt_regs_off(const char *reg_name) 
	return -ENOENT;

}



static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg)

static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg, int *arg_sz)

{

	char reg_name[16];

	int arg_sz, len, reg_off;

	int len, reg_off;

	long off;



	if (sscanf(arg_str, " %d @ %ld ( %15[a-z0-9] ) %n", &arg_sz, &off, reg_name, &len) == 3) {

	if (sscanf(arg_str, " %d @ %ld ( %15[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;
@@ -1470,12 +1444,12 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec 
		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) {

	} 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 @ %15[a-z0-9] %n", &arg_sz, reg_name, &len) == 2) {

	} else if (sscanf(arg_str, " %d @ %15[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;
@@ -1488,17 +1462,83 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec 
		return -EINVAL;

	}



	arg->arg_signed = arg_sz < 0;

	if (arg_sz < 0)

		arg_sz = -arg_sz;

	return len;

}



	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);

#elif defined(__arm__)



static int calc_pt_regs_off(const char *reg_name)

{

	static struct {

		const char *name;

		size_t pt_regs_off;

	} reg_map[] = {

		{ "r0", offsetof(struct pt_regs, uregs[0]) },

		{ "r1", offsetof(struct pt_regs, uregs[1]) },

		{ "r2", offsetof(struct pt_regs, uregs[2]) },

		{ "r3", offsetof(struct pt_regs, uregs[3]) },

		{ "r4", offsetof(struct pt_regs, uregs[4]) },

		{ "r5", offsetof(struct pt_regs, uregs[5]) },

		{ "r6", offsetof(struct pt_regs, uregs[6]) },

		{ "r7", offsetof(struct pt_regs, uregs[7]) },

		{ "r8", offsetof(struct pt_regs, uregs[8]) },

		{ "r9", offsetof(struct pt_regs, uregs[9]) },

		{ "r10", offsetof(struct pt_regs, uregs[10]) },

		{ "fp", offsetof(struct pt_regs, uregs[11]) },

		{ "ip", offsetof(struct pt_regs, uregs[12]) },

		{ "sp", offsetof(struct pt_regs, uregs[13]) },

		{ "lr", offsetof(struct pt_regs, uregs[14]) },

		{ "pc", offsetof(struct pt_regs, uregs[15]) },

	};

	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, int *arg_sz)

{

	char reg_name[16];

	int len, reg_off;

	long off;



	if (sscanf(arg_str, " %d @ \[ %15[a-z0-9] , #%ld ] %n",

		   arg_sz, reg_name, &off, &len) == 3) {

		/* Memory dereference case, e.g., -4@[fp, #96] */

		arg->arg_type = USDT_ARG_REG_DEREF;

		arg->val_off = off;

		reg_off = calc_pt_regs_off(reg_name);

		if (reg_off < 0)

			return reg_off;

		arg->reg_off = reg_off;

	} else if (sscanf(arg_str, " %d @ \[ %15[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);

		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 @ %15[a-z0-9] %n", arg_sz, reg_name, &len) == 2) {

		/* Register read case, e.g., -8@r4 */

		arg->arg_type = USDT_ARG_REG;

		arg->val_off = 0;

		reg_off = calc_pt_regs_off(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;

	}
@@ -1507,7 +1547,7 @@ static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec 


#else



static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg)

static int parse_usdt_arg(const char *arg_str, int arg_num, struct usdt_arg_spec *arg, int *arg_sz)

{

	pr_warn("usdt: libbpf doesn't support USDTs on current architecture\n");

	return -ENOTSUP;