Merge branch 'bpf: Support struct argument for trampoline base progs'

Yonghong Song says:

====================
Currently struct arguments are not supported for trampoline based progs.
One of major reason is that struct argument may pass by value which may
use more than one registers. This breaks trampoline progs where
each argument is assumed to take one register. bcc community reported the
issue ([1]) where struct argument is not supported for fentry program.
  typedef struct {
        uid_t val;
  } kuid_t;
  typedef struct {
        gid_t val;
  } kgid_t;
  int security_path_chown(struct path *path, kuid_t uid, kgid_t gid);
Inside Meta, we also have a use case to attach to tcp_setsockopt()
  typedef struct {
        union {
                void            *kernel;
                void __user     *user;
        };
        bool            is_kernel : 1;
  } sockptr_t;
  int tcp_setsockopt(struct sock *sk, int level, int optname,
                     sockptr_t optval, unsigned int optlen);

This patch added struct value support for bpf tracing programs which
uses trampoline. Only <= 16 byte struct size is supported for now
which covers use cases in the above. For x86/arm64/bpf, <= 16
struct value will be passed in registers instead of by reference.
Only x86_64 is supported in this patch. arm64 support can be
added later.

 [1] https://github.com/iovisor/bcc/issues/3657

Changelog:
  v3 -> v4:
   - fix a test failure where no casting for
     bpf_get_func_arg() value as the value type is 'int'.
   - add tracing_struct test in DENYLIST.s390x
   - simplify macro BPF_REG_CNT for BPF_PROG2.
  v2 -> v3:
   - previously struct arguments (<= 16 bytes) are passed
     by reference for bpf programs. Suggested by Alexei,
     it is passed by value now.
   - in order to support passing <= 16 struct value, a
     new macro BPF_PROG2 is invented.
  rfc v1 -> v2:
   - changed bpf_func_model struct info fields to
     arg_flags[] to make it easy to iterate arguments
     in arch specific {save|restore}_regs() functions.
   - added fexit tests to test return values with
     struct arguments.
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

arch/arm64/net/bpf_jit_comp.c

@@ -1970,7 +1970,7 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image,
 				u32 flags, struct bpf_tramp_links *tlinks,
 				void *orig_call)
 {
-	int ret;
+	int i, ret;
 	int nargs = m->nr_args;
 	int max_insns = ((long)image_end - (long)image) / AARCH64_INSN_SIZE;
 	struct jit_ctx ctx = {
@@ -1982,6 +1982,12 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image,
 	if (nargs > 8)
 		return -ENOTSUPP;
 
+	/* don't support struct argument */
+	for (i = 0; i < MAX_BPF_FUNC_ARGS; i++) {
+		if (m->arg_flags[i] & BTF_FMODEL_STRUCT_ARG)
+			return -ENOTSUPP;
+	}
+
 	ret = prepare_trampoline(&ctx, im, tlinks, orig_call, nargs, flags);
 	if (ret < 0)
 		return ret;

arch/x86/net/bpf_jit_comp.c

@@ -1751,34 +1751,60 @@ st:			if (is_imm8(insn->off))
 static void save_regs(const struct btf_func_model *m, u8 **prog, int nr_args,
 		      int stack_size)
 {
-	int i;
+	int i, j, arg_size, nr_regs;
 	/* Store function arguments to stack.
 	 * For a function that accepts two pointers the sequence will be:
 	 * mov QWORD PTR [rbp-0x10],rdi
 	 * mov QWORD PTR [rbp-0x8],rsi
 	 */
-	for (i = 0; i < min(nr_args, 6); i++)
-		emit_stx(prog, bytes_to_bpf_size(m->arg_size[i]),
-			 BPF_REG_FP,
-			 i == 5 ? X86_REG_R9 : BPF_REG_1 + i,
-			 -(stack_size - i * 8));
+	for (i = 0, j = 0; i < min(nr_args, 6); i++) {
+		if (m->arg_flags[i] & BTF_FMODEL_STRUCT_ARG) {
+			nr_regs = (m->arg_size[i] + 7) / 8;
+			arg_size = 8;
+		} else {
+			nr_regs = 1;
+			arg_size = m->arg_size[i];
+		}
+
+		while (nr_regs) {
+			emit_stx(prog, bytes_to_bpf_size(arg_size),
+				 BPF_REG_FP,
+				 j == 5 ? X86_REG_R9 : BPF_REG_1 + j,
+				 -(stack_size - j * 8));
+			nr_regs--;
+			j++;
+		}
+	}
 }
 
 static void restore_regs(const struct btf_func_model *m, u8 **prog, int nr_args,
 			 int stack_size)
 {
-	int i;
+	int i, j, arg_size, nr_regs;
 
 	/* Restore function arguments from stack.
 	 * For a function that accepts two pointers the sequence will be:
 	 * EMIT4(0x48, 0x8B, 0x7D, 0xF0); mov rdi,QWORD PTR [rbp-0x10]
 	 * EMIT4(0x48, 0x8B, 0x75, 0xF8); mov rsi,QWORD PTR [rbp-0x8]
 	 */
-	for (i = 0; i < min(nr_args, 6); i++)
-		emit_ldx(prog, bytes_to_bpf_size(m->arg_size[i]),
-			 i == 5 ? X86_REG_R9 : BPF_REG_1 + i,
-			 BPF_REG_FP,
-			 -(stack_size - i * 8));
+	for (i = 0, j = 0; i < min(nr_args, 6); i++) {
+		if (m->arg_flags[i] & BTF_FMODEL_STRUCT_ARG) {
+			nr_regs = (m->arg_size[i] + 7) / 8;
+			arg_size = 8;
+		} else {
+			nr_regs = 1;
+			arg_size = m->arg_size[i];
+		}
+
+		while (nr_regs) {
+			emit_ldx(prog, bytes_to_bpf_size(arg_size),
+				 j == 5 ? X86_REG_R9 : BPF_REG_1 + j,
+				 BPF_REG_FP,
+				 -(stack_size - j * 8));
+			nr_regs--;
+			j++;
+		}
+	}
 }
 
 static int invoke_bpf_prog(const struct btf_func_model *m, u8 **pprog,
@@ -2015,7 +2041,7 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
 				struct bpf_tramp_links *tlinks,
 				void *orig_call)
 {
-	int ret, i, nr_args = m->nr_args;
+	int ret, i, nr_args = m->nr_args, extra_nregs = 0;
 	int regs_off, ip_off, args_off, stack_size = nr_args * 8, run_ctx_off;
 	struct bpf_tramp_links *fentry = &tlinks[BPF_TRAMP_FENTRY];
 	struct bpf_tramp_links *fexit = &tlinks[BPF_TRAMP_FEXIT];
@@ -2028,6 +2054,14 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
 	if (nr_args > 6)
 		return -ENOTSUPP;
 
+	for (i = 0; i < MAX_BPF_FUNC_ARGS; i++) {
+		if (m->arg_flags[i] & BTF_FMODEL_STRUCT_ARG)
+			extra_nregs += (m->arg_size[i] + 7) / 8 - 1;
+	}
+	if (nr_args + extra_nregs > 6)
+		return -ENOTSUPP;
+	stack_size += extra_nregs * 8;
+
 	/* Generated trampoline stack layout:
 	 *
 	 * RBP + 8         [ return address  ]
@@ -2040,7 +2074,7 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
 	 *                 [ ...             ]
 	 * RBP - regs_off  [ reg_arg1        ]  program's ctx pointer
 	 *
-	 * RBP - args_off  [ args count      ]  always
+	 * RBP - args_off  [ arg regs count  ]  always
 	 *
 	 * RBP - ip_off    [ traced function ]  BPF_TRAMP_F_IP_ARG flag
 	 *
@@ -2083,11 +2117,11 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
 	EMIT4(0x48, 0x83, 0xEC, stack_size); /* sub rsp, stack_size */
 	EMIT1(0x53);		 /* push rbx */
 
-	/* Store number of arguments of the traced function:
-	 *   mov rax, nr_args
+	/* Store number of argument registers of the traced function:
+	 *   mov rax, nr_args + extra_nregs
 	 *   mov QWORD PTR [rbp - args_off], rax
 	 */
-	emit_mov_imm64(&prog, BPF_REG_0, 0, (u32) nr_args);
+	emit_mov_imm64(&prog, BPF_REG_0, 0, (u32) nr_args + extra_nregs);
 	emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -args_off);
 
 	if (flags & BPF_TRAMP_F_IP_ARG) {

include/linux/bpf.h

@@ -727,10 +727,14 @@ enum bpf_cgroup_storage_type {
  */
 #define MAX_BPF_FUNC_REG_ARGS 5
 
+/* The argument is a structure. */
+#define BTF_FMODEL_STRUCT_ARG		BIT(0)
+
 struct btf_func_model {
 	u8 ret_size;
 	u8 nr_args;
 	u8 arg_size[MAX_BPF_FUNC_ARGS];
+	u8 arg_flags[MAX_BPF_FUNC_ARGS];
 };
 
 /* Restore arguments before returning from trampoline to let original function

include/uapi/linux/bpf.h

@@ -5079,12 +5079,12 @@ union bpf_attr {
  *
  * long bpf_get_func_arg(void *ctx, u32 n, u64 *value)
  *	Description
- *		Get **n**-th argument (zero based) of the traced function (for tracing programs)
+ *		Get **n**-th argument register (zero based) of the traced function (for tracing programs)
  *		returned in **value**.
  *
  *	Return
  *		0 on success.
- *		**-EINVAL** if n >= arguments count of traced function.
+ *		**-EINVAL** if n >= argument register count of traced function.
  *
  * long bpf_get_func_ret(void *ctx, u64 *value)
  *	Description
@@ -5097,10 +5097,11 @@ union bpf_attr {
  *
  * long bpf_get_func_arg_cnt(void *ctx)
  *	Description
- *		Get number of arguments of the traced function (for tracing programs).
+ *		Get number of registers of the traced function (for tracing programs) where
+ *		function arguments are stored in these registers.
  *
  *	Return
- *		The number of arguments of the traced function.
+ *		The number of argument registers of the traced function.
  *
  * int bpf_get_retval(void)
  *	Description

kernel/bpf/btf.c

@@ -5328,6 +5328,34 @@ static bool is_int_ptr(struct btf *btf, const struct btf_type *t)
 	return btf_type_is_int(t);
 }
 
+static u32 get_ctx_arg_idx(struct btf *btf, const struct btf_type *func_proto,
+			   int off)
+{
+	const struct btf_param *args;
+	const struct btf_type *t;
+	u32 offset = 0, nr_args;
+	int i;
+
+	if (!func_proto)
+		return off / 8;
+
+	nr_args = btf_type_vlen(func_proto);
+	args = (const struct btf_param *)(func_proto + 1);
+	for (i = 0; i < nr_args; i++) {
+		t = btf_type_skip_modifiers(btf, args[i].type, NULL);
+		offset += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8);
+		if (off < offset)
+			return i;
+	}
+
+	t = btf_type_skip_modifiers(btf, func_proto->type, NULL);
+	offset += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8);
+	if (off < offset)
+		return nr_args;
+
+	return nr_args + 1;
+}
+
 bool btf_ctx_access(int off, int size, enum bpf_access_type type,
 		    const struct bpf_prog *prog,
 		    struct bpf_insn_access_aux *info)
@@ -5347,7 +5375,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type,
 			tname, off);
 		return false;
 	}
-	arg = off / 8;
+	arg = get_ctx_arg_idx(btf, t, off);
 	args = (const struct btf_param *)(t + 1);
 	/* if (t == NULL) Fall back to default BPF prog with
 	 * MAX_BPF_FUNC_REG_ARGS u64 arguments.
@@ -5417,7 +5445,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type,
 	/* skip modifiers */
 	while (btf_type_is_modifier(t))
 		t = btf_type_by_id(btf, t->type);
-	if (btf_type_is_small_int(t) || btf_is_any_enum(t))
+	if (btf_type_is_small_int(t) || btf_is_any_enum(t) || __btf_type_is_struct(t))
 		/* accessing a scalar */
 		return true;
 	if (!btf_type_is_ptr(t)) {
@@ -5881,7 +5909,7 @@ static int __get_type_size(struct btf *btf, u32 btf_id,
 	if (btf_type_is_ptr(t))
 		/* kernel size of pointer. Not BPF's size of pointer*/
 		return sizeof(void *);
-	if (btf_type_is_int(t) || btf_is_any_enum(t))
+	if (btf_type_is_int(t) || btf_is_any_enum(t) || __btf_type_is_struct(t))
 		return t->size;
 	return -EINVAL;
 }
@@ -5901,8 +5929,10 @@ int btf_distill_func_proto(struct bpf_verifier_log *log,
 		/* BTF function prototype doesn't match the verifier types.
 		 * Fall back to MAX_BPF_FUNC_REG_ARGS u64 args.
 		 */
-		for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++)
+		for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) {
 			m->arg_size[i] = 8;
+			m->arg_flags[i] = 0;
+		}
 		m->ret_size = 8;
 		m->nr_args = MAX_BPF_FUNC_REG_ARGS;
 		return 0;
@@ -5916,7 +5946,7 @@ int btf_distill_func_proto(struct bpf_verifier_log *log,
 		return -EINVAL;
 	}
 	ret = __get_type_size(btf, func->type, &t);
-	if (ret < 0) {
+	if (ret < 0 || __btf_type_is_struct(t)) {
 		bpf_log(log,
 			"The function %s return type %s is unsupported.\n",
 			tname, btf_kind_str[BTF_INFO_KIND(t->info)]);
@@ -5932,7 +5962,9 @@ int btf_distill_func_proto(struct bpf_verifier_log *log,
 			return -EINVAL;
 		}
 		ret = __get_type_size(btf, args[i].type, &t);
-		if (ret < 0) {
+
+		/* No support of struct argument size greater than 16 bytes */
+		if (ret < 0 || ret > 16) {
 			bpf_log(log,
 				"The function %s arg%d type %s is unsupported.\n",
 				tname, i, btf_kind_str[BTF_INFO_KIND(t->info)]);
@@ -5945,6 +5977,7 @@ int btf_distill_func_proto(struct bpf_verifier_log *log,
 			return -EINVAL;
 		}
 		m->arg_size[i] = ret;
+		m->arg_flags[i] = __btf_type_is_struct(t) ? BTF_FMODEL_STRUCT_ARG : 0;
 	}
 	m->nr_args = nargs;
 	return 0;

tools/include/uapi/linux/bpf.h

@@ -5079,12 +5079,12 @@ union bpf_attr {
  *
  * long bpf_get_func_arg(void *ctx, u32 n, u64 *value)
  *	Description
- *		Get **n**-th argument (zero based) of the traced function (for tracing programs)
+ *		Get **n**-th argument register (zero based) of the traced function (for tracing programs)
  *		returned in **value**.
  *
  *	Return
  *		0 on success.
- *		**-EINVAL** if n >= arguments count of traced function.
+ *		**-EINVAL** if n >= argument register count of traced function.
  *
  * long bpf_get_func_ret(void *ctx, u64 *value)
  *	Description
@@ -5097,10 +5097,11 @@ union bpf_attr {
  *
  * long bpf_get_func_arg_cnt(void *ctx)
  *	Description
- *		Get number of arguments of the traced function (for tracing programs).
+ *		Get number of registers of the traced function (for tracing programs) where
+ *		function arguments are stored in these registers.
  *
  *	Return
- *		The number of arguments of the traced function.
+ *		The number of argument registers of the traced function.
  *
  * int bpf_get_retval(void)
  *	Description

tools/lib/bpf/bpf_tracing.h

@@ -438,6 +438,85 @@ typeof(name(0)) name(unsigned long long *ctx)				    \
 static __always_inline typeof(name(0))					    \
 ____##name(unsigned long long *ctx, ##args)
 
+#ifndef ____bpf_nth
+#define ____bpf_nth(_, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13, _14, _15, _16, _17, _18, _19, _20, _21, _22, _23, _24, N, ...) N
+#endif
+#ifndef ____bpf_narg
+#define ____bpf_narg(...) ____bpf_nth(_, ##__VA_ARGS__, 12, 12, 11, 11, 10, 10, 9, 9, 8, 8, 7, 7, 6, 6, 5, 5, 4, 4, 3, 3, 2, 2, 1, 1, 0)
+#endif
+
+#define BPF_REG_CNT(t) \
+	(__builtin_choose_expr(sizeof(t) == 1 || sizeof(t) == 2 || sizeof(t) == 4 || sizeof(t) == 8, 1,	\
+	 __builtin_choose_expr(sizeof(t) == 16, 2,							\
+			       (void)0)))
+
+#define ____bpf_reg_cnt0()			(0)
+#define ____bpf_reg_cnt1(t, x)			(____bpf_reg_cnt0() + BPF_REG_CNT(t))
+#define ____bpf_reg_cnt2(t, x, args...)		(____bpf_reg_cnt1(args) + BPF_REG_CNT(t))
+#define ____bpf_reg_cnt3(t, x, args...)		(____bpf_reg_cnt2(args) + BPF_REG_CNT(t))
+#define ____bpf_reg_cnt4(t, x, args...)		(____bpf_reg_cnt3(args) + BPF_REG_CNT(t))
+#define ____bpf_reg_cnt5(t, x, args...)		(____bpf_reg_cnt4(args) + BPF_REG_CNT(t))
+#define ____bpf_reg_cnt6(t, x, args...)		(____bpf_reg_cnt5(args) + BPF_REG_CNT(t))
+#define ____bpf_reg_cnt7(t, x, args...)		(____bpf_reg_cnt6(args) + BPF_REG_CNT(t))
+#define ____bpf_reg_cnt8(t, x, args...)		(____bpf_reg_cnt7(args) + BPF_REG_CNT(t))
+#define ____bpf_reg_cnt9(t, x, args...)		(____bpf_reg_cnt8(args) + BPF_REG_CNT(t))
+#define ____bpf_reg_cnt10(t, x, args...)	(____bpf_reg_cnt9(args) + BPF_REG_CNT(t))
+#define ____bpf_reg_cnt11(t, x, args...)	(____bpf_reg_cnt10(args) + BPF_REG_CNT(t))
+#define ____bpf_reg_cnt12(t, x, args...)	(____bpf_reg_cnt11(args) + BPF_REG_CNT(t))
+#define ____bpf_reg_cnt(args...)	 ___bpf_apply(____bpf_reg_cnt, ____bpf_narg(args))(args)
+
+#define ____bpf_union_arg(t, x, n) \
+	__builtin_choose_expr(sizeof(t) == 1, ({ union { struct { __u8 x; } ___z; t x; } ___tmp = { .___z = {ctx[n]}}; ___tmp.x; }), \
+	__builtin_choose_expr(sizeof(t) == 2, ({ union { struct { __u16 x; } ___z; t x; } ___tmp = { .___z = {ctx[n]} }; ___tmp.x; }), \
+	__builtin_choose_expr(sizeof(t) == 4, ({ union { struct { __u32 x; } ___z; t x; } ___tmp = { .___z = {ctx[n]} }; ___tmp.x; }), \
+	__builtin_choose_expr(sizeof(t) == 8, ({ union { struct { __u64 x; } ___z; t x; } ___tmp = {.___z = {ctx[n]} }; ___tmp.x; }), \
+	__builtin_choose_expr(sizeof(t) == 16, ({ union { struct { __u64 x, y; } ___z; t x; } ___tmp = {.___z = {ctx[n], ctx[n + 1]} }; ___tmp.x; }), \
+			      (void)0)))))
+
+#define ____bpf_ctx_arg0(n, args...)
+#define ____bpf_ctx_arg1(n, t, x)		, ____bpf_union_arg(t, x, n - ____bpf_reg_cnt1(t, x))
+#define ____bpf_ctx_arg2(n, t, x, args...)	, ____bpf_union_arg(t, x, n - ____bpf_reg_cnt2(t, x, args)) ____bpf_ctx_arg1(n, args)
+#define ____bpf_ctx_arg3(n, t, x, args...)	, ____bpf_union_arg(t, x, n - ____bpf_reg_cnt3(t, x, args)) ____bpf_ctx_arg2(n, args)
+#define ____bpf_ctx_arg4(n, t, x, args...)	, ____bpf_union_arg(t, x, n - ____bpf_reg_cnt4(t, x, args)) ____bpf_ctx_arg3(n, args)
+#define ____bpf_ctx_arg5(n, t, x, args...)	, ____bpf_union_arg(t, x, n - ____bpf_reg_cnt5(t, x, args)) ____bpf_ctx_arg4(n, args)
+#define ____bpf_ctx_arg6(n, t, x, args...)	, ____bpf_union_arg(t, x, n - ____bpf_reg_cnt6(t, x, args)) ____bpf_ctx_arg5(n, args)
+#define ____bpf_ctx_arg7(n, t, x, args...)	, ____bpf_union_arg(t, x, n - ____bpf_reg_cnt7(t, x, args)) ____bpf_ctx_arg6(n, args)
+#define ____bpf_ctx_arg8(n, t, x, args...)	, ____bpf_union_arg(t, x, n - ____bpf_reg_cnt8(t, x, args)) ____bpf_ctx_arg7(n, args)
+#define ____bpf_ctx_arg9(n, t, x, args...)	, ____bpf_union_arg(t, x, n - ____bpf_reg_cnt9(t, x, args)) ____bpf_ctx_arg8(n, args)
+#define ____bpf_ctx_arg10(n, t, x, args...)	, ____bpf_union_arg(t, x, n - ____bpf_reg_cnt10(t, x, args)) ____bpf_ctx_arg9(n, args)
+#define ____bpf_ctx_arg11(n, t, x, args...)	, ____bpf_union_arg(t, x, n - ____bpf_reg_cnt11(t, x, args)) ____bpf_ctx_arg10(n, args)
+#define ____bpf_ctx_arg12(n, t, x, args...)	, ____bpf_union_arg(t, x, n - ____bpf_reg_cnt12(t, x, args)) ____bpf_ctx_arg11(n, args)
+#define ____bpf_ctx_arg(n, args...)	___bpf_apply(____bpf_ctx_arg, ____bpf_narg(args))(n, args)
+
+#define ____bpf_ctx_decl0()
+#define ____bpf_ctx_decl1(t, x)			, t x
+#define ____bpf_ctx_decl2(t, x, args...)	, t x ____bpf_ctx_decl1(args)
+#define ____bpf_ctx_decl3(t, x, args...)	, t x ____bpf_ctx_decl2(args)
+#define ____bpf_ctx_decl4(t, x, args...)	, t x ____bpf_ctx_decl3(args)
+#define ____bpf_ctx_decl5(t, x, args...)	, t x ____bpf_ctx_decl4(args)
+#define ____bpf_ctx_decl6(t, x, args...)	, t x ____bpf_ctx_decl5(args)
+#define ____bpf_ctx_decl7(t, x, args...)	, t x ____bpf_ctx_decl6(args)
+#define ____bpf_ctx_decl8(t, x, args...)	, t x ____bpf_ctx_decl7(args)
+#define ____bpf_ctx_decl9(t, x, args...)	, t x ____bpf_ctx_decl8(args)
+#define ____bpf_ctx_decl10(t, x, args...)	, t x ____bpf_ctx_decl9(args)
+#define ____bpf_ctx_decl11(t, x, args...)	, t x ____bpf_ctx_decl10(args)
+#define ____bpf_ctx_decl12(t, x, args...)	, t x ____bpf_ctx_decl11(args)
+#define ____bpf_ctx_decl(args...)	___bpf_apply(____bpf_ctx_decl, ____bpf_narg(args))(args)
+
+/*
+ * BPF_PROG2 can handle struct arguments.
+ */
+#define BPF_PROG2(name, args...)						\
+name(unsigned long long *ctx);							\
+static __always_inline typeof(name(0))						\
+____##name(unsigned long long *ctx ____bpf_ctx_decl(args));			\
+typeof(name(0)) name(unsigned long long *ctx)					\
+{										\
+	return ____##name(ctx ____bpf_ctx_arg(____bpf_reg_cnt(args), args));	\
+}										\
+static __always_inline typeof(name(0))						\
+____##name(unsigned long long *ctx ____bpf_ctx_decl(args))
+
 struct pt_regs;
 
 #define ___bpf_kprobe_args0()           ctx

tools/testing/selftests/bpf/DENYLIST.s390x

@@ -70,3 +70,4 @@ setget_sockopt                           # attach unexpected error: -524
 cb_refs                                  # expected error message unexpected error: -524                               (trampoline)
 cgroup_hierarchical_stats                # JIT does not support calling kernel function                                (kfunc)
 htab_update                              # failed to attach: ERROR: strerror_r(-524)=22                                (trampoline)
+tracing_struct                           # failed to auto-attach: -524                                                 (trampoline)

tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c

@@ -18,6 +18,46 @@ typedef int (*func_proto_typedef_nested1)(func_proto_typedef);
 typedef int (*func_proto_typedef_nested2)(func_proto_typedef_nested1);
 
 DEFINE_PER_CPU(int, bpf_testmod_ksym_percpu) = 123;
+long bpf_testmod_test_struct_arg_result;
+
+struct bpf_testmod_struct_arg_1 {
+	int a;
+};
+struct bpf_testmod_struct_arg_2 {
+	long a;
+	long b;
+};
+
+noinline int
+bpf_testmod_test_struct_arg_1(struct bpf_testmod_struct_arg_2 a, int b, int c) {
+	bpf_testmod_test_struct_arg_result = a.a + a.b  + b + c;
+	return bpf_testmod_test_struct_arg_result;
+}
+
+noinline int
+bpf_testmod_test_struct_arg_2(int a, struct bpf_testmod_struct_arg_2 b, int c) {
+	bpf_testmod_test_struct_arg_result = a + b.a + b.b + c;
+	return bpf_testmod_test_struct_arg_result;
+}
+
+noinline int
+bpf_testmod_test_struct_arg_3(int a, int b, struct bpf_testmod_struct_arg_2 c) {
+	bpf_testmod_test_struct_arg_result = a + b + c.a + c.b;
+	return bpf_testmod_test_struct_arg_result;
+}
+
+noinline int
+bpf_testmod_test_struct_arg_4(struct bpf_testmod_struct_arg_1 a, int b,
+			      int c, int d, struct bpf_testmod_struct_arg_2 e) {
+	bpf_testmod_test_struct_arg_result = a.a + b + c + d + e.a + e.b;
+	return bpf_testmod_test_struct_arg_result;
+}
+
+noinline int
+bpf_testmod_test_struct_arg_5(void) {
+	bpf_testmod_test_struct_arg_result = 1;
+	return bpf_testmod_test_struct_arg_result;
+}
 
 noinline void
 bpf_testmod_test_mod_kfunc(int i)
@@ -98,11 +138,19 @@ bpf_testmod_test_read(struct file *file, struct kobject *kobj,
 		.off = off,
 		.len = len,
 	};
+	struct bpf_testmod_struct_arg_1 struct_arg1 = {10};
+	struct bpf_testmod_struct_arg_2 struct_arg2 = {2, 3};
 	int i = 1;
 
 	while (bpf_testmod_return_ptr(i))
 		i++;
 
+	(void)bpf_testmod_test_struct_arg_1(struct_arg2, 1, 4);
+	(void)bpf_testmod_test_struct_arg_2(1, struct_arg2, 4);
+	(void)bpf_testmod_test_struct_arg_3(1, 4, struct_arg2);
+	(void)bpf_testmod_test_struct_arg_4(struct_arg1, 1, 2, 3, struct_arg2);
+	(void)bpf_testmod_test_struct_arg_5();
+
 	/* This is always true. Use the check to make sure the compiler
 	 * doesn't remove bpf_testmod_loop_test.
 	 */

tools/testing/selftests/bpf/prog_tests/tracing_struct.c

+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
+
+#include <test_progs.h>
+#include "tracing_struct.skel.h"
+
+static void test_fentry(void)
+{
+	struct tracing_struct *skel;
+	int err;
+
+	skel = tracing_struct__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "tracing_struct__open_and_load"))
+		return;
+
+	err = tracing_struct__attach(skel);
+	if (!ASSERT_OK(err, "tracing_struct__attach"))
+		return;
+
+	ASSERT_OK(trigger_module_test_read(256), "trigger_read");
+
+	ASSERT_EQ(skel->bss->t1_a_a, 2, "t1:a.a");
+	ASSERT_EQ(skel->bss->t1_a_b, 3, "t1:a.b");
+	ASSERT_EQ(skel->bss->t1_b, 1, "t1:b");
+	ASSERT_EQ(skel->bss->t1_c, 4, "t1:c");
+
+	ASSERT_EQ(skel->bss->t1_nregs, 4, "t1 nregs");
+	ASSERT_EQ(skel->bss->t1_reg0, 2, "t1 reg0");
+	ASSERT_EQ(skel->bss->t1_reg1, 3, "t1 reg1");
+	ASSERT_EQ(skel->bss->t1_reg2, 1, "t1 reg2");
+	ASSERT_EQ(skel->bss->t1_reg3, 4, "t1 reg3");
+	ASSERT_EQ(skel->bss->t1_ret, 10, "t1 ret");
+
+	ASSERT_EQ(skel->bss->t2_a, 1, "t2:a");
+	ASSERT_EQ(skel->bss->t2_b_a, 2, "t2:b.a");
+	ASSERT_EQ(skel->bss->t2_b_b, 3, "t2:b.b");
+	ASSERT_EQ(skel->bss->t2_c, 4, "t2:c");
+	ASSERT_EQ(skel->bss->t2_ret, 10, "t2 ret");
+
+	ASSERT_EQ(skel->bss->t3_a, 1, "t3:a");
+	ASSERT_EQ(skel->bss->t3_b, 4, "t3:b");
+	ASSERT_EQ(skel->bss->t3_c_a, 2, "t3:c.a");
+	ASSERT_EQ(skel->bss->t3_c_b, 3, "t3:c.b");
+	ASSERT_EQ(skel->bss->t3_ret, 10, "t3 ret");
+
+	ASSERT_EQ(skel->bss->t4_a_a, 10, "t4:a.a");
+	ASSERT_EQ(skel->bss->t4_b, 1, "t4:b");
+	ASSERT_EQ(skel->bss->t4_c, 2, "t4:c");
+	ASSERT_EQ(skel->bss->t4_d, 3, "t4:d");
+	ASSERT_EQ(skel->bss->t4_e_a, 2, "t4:e.a");
+	ASSERT_EQ(skel->bss->t4_e_b, 3, "t4:e.b");
+	ASSERT_EQ(skel->bss->t4_ret, 21, "t4 ret");
+
+	ASSERT_EQ(skel->bss->t5_ret, 1, "t5 ret");
+
+	tracing_struct__detach(skel);
+	tracing_struct__destroy(skel);
+}
+
+void test_tracing_struct(void)
+{
+	test_fentry();
+}

tools/testing/selftests/bpf/progs/timer.c

@@ -120,7 +120,7 @@ static int timer_cb1(void *map, int *key, struct bpf_timer *timer)
 }
 
 SEC("fentry/bpf_fentry_test1")
-int BPF_PROG(test1, int a)
+int BPF_PROG2(test1, int, a)
 {
 	struct bpf_timer *arr_timer, *lru_timer;
 	struct elem init = {};
@@ -236,7 +236,7 @@ int bpf_timer_test(void)
 }
 
 SEC("fentry/bpf_fentry_test2")
-int BPF_PROG(test2, int a, int b)
+int BPF_PROG2(test2, int, a, int, b)
 {
 	struct hmap_elem init = {}, *val;
 	int key = HTAB, key_malloc = HTAB_MALLOC;

tools/testing/selftests/bpf/progs/tracing_struct.c

+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
+
+#include <vmlinux.h>
+#include <bpf/bpf_tracing.h>
+#include <bpf/bpf_helpers.h>
+
+struct bpf_testmod_struct_arg_1 {
+	int a;
+};
+struct bpf_testmod_struct_arg_2 {
+	long a;
+	long b;
+};
+
+long t1_a_a, t1_a_b, t1_b, t1_c, t1_ret, t1_nregs;
+__u64 t1_reg0, t1_reg1, t1_reg2, t1_reg3;
+long t2_a, t2_b_a, t2_b_b, t2_c, t2_ret;
+long t3_a, t3_b, t3_c_a, t3_c_b, t3_ret;
+long t4_a_a, t4_b, t4_c, t4_d, t4_e_a, t4_e_b, t4_ret;
+long t5_ret;
+
+SEC("fentry/bpf_testmod_test_struct_arg_1")
+int BPF_PROG2(test_struct_arg_1, struct bpf_testmod_struct_arg_2, a, int, b, int, c)
+{
+	t1_a_a = a.a;
+	t1_a_b = a.b;
+	t1_b = b;
+	t1_c = c;
+	return 0;
+}
+
+SEC("fexit/bpf_testmod_test_struct_arg_1")
+int BPF_PROG2(test_struct_arg_2, struct bpf_testmod_struct_arg_2, a, int, b, int, c, int, ret)
+{
+	t1_nregs =  bpf_get_func_arg_cnt(ctx);
+	/* a.a */
+	bpf_get_func_arg(ctx, 0, &t1_reg0);
+	/* a.b */
+	bpf_get_func_arg(ctx, 1, &t1_reg1);
+	/* b */
+	bpf_get_func_arg(ctx, 2, &t1_reg2);
+	t1_reg2 = (int)t1_reg2;
+	/* c */
+	bpf_get_func_arg(ctx, 3, &t1_reg3);
+	t1_reg3 = (int)t1_reg3;
+
+	t1_ret = ret;
+	return 0;
+}
+
+SEC("fentry/bpf_testmod_test_struct_arg_2")
+int BPF_PROG2(test_struct_arg_3, int, a, struct bpf_testmod_struct_arg_2, b, int, c)
+{
+	t2_a = a;
+	t2_b_a = b.a;
+	t2_b_b = b.b;
+	t2_c = c;
+	return 0;
+}
+
+SEC("fexit/bpf_testmod_test_struct_arg_2")
+int BPF_PROG2(test_struct_arg_4, int, a, struct bpf_testmod_struct_arg_2, b, int, c, int, ret)
+{
+	t2_ret = ret;
+	return 0;
+}
+
+SEC("fentry/bpf_testmod_test_struct_arg_3")
+int BPF_PROG2(test_struct_arg_5, int, a, int, b, struct bpf_testmod_struct_arg_2, c)
+{
+	t3_a = a;
+	t3_b = b;
+	t3_c_a = c.a;
+	t3_c_b = c.b;
+	return 0;
+}
+
+SEC("fexit/bpf_testmod_test_struct_arg_3")
+int BPF_PROG2(test_struct_arg_6, int, a, int, b, struct bpf_testmod_struct_arg_2, c, int, ret)
+{
+	t3_ret = ret;
+	return 0;
+}
+
+SEC("fentry/bpf_testmod_test_struct_arg_4")
+int BPF_PROG2(test_struct_arg_7, struct bpf_testmod_struct_arg_1, a, int, b,
+	     int, c, int, d, struct bpf_testmod_struct_arg_2, e)
+{
+	t4_a_a = a.a;
+	t4_b = b;
+	t4_c = c;
+	t4_d = d;
+	t4_e_a = e.a;
+	t4_e_b = e.b;
+	return 0;
+}
+
+SEC("fexit/bpf_testmod_test_struct_arg_4")
+int BPF_PROG2(test_struct_arg_8, struct bpf_testmod_struct_arg_1, a, int, b,
+	     int, c, int, d, struct bpf_testmod_struct_arg_2, e, int, ret)
+{
+	t4_ret = ret;
+	return 0;
+}
+
+SEC("fentry/bpf_testmod_test_struct_arg_5")
+int BPF_PROG2(test_struct_arg_9)
+{
+	return 0;
+}
+
+SEC("fexit/bpf_testmod_test_struct_arg_5")
+int BPF_PROG2(test_struct_arg_10, int, ret)
+{
+	t5_ret = ret;
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";