1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef _ASM_S390_STACKTRACE_H
  3#define _ASM_S390_STACKTRACE_H
  4
  5#include <linux/uaccess.h>
  6#include <linux/ptrace.h>
  7#include <asm/switch_to.h>
  8
  9enum stack_type {
 10	STACK_TYPE_UNKNOWN,
 11	STACK_TYPE_TASK,
 12	STACK_TYPE_IRQ,
 13	STACK_TYPE_NODAT,
 14	STACK_TYPE_RESTART,
 15	STACK_TYPE_MCCK,
 16};
 17
 18struct stack_info {
 19	enum stack_type type;
 20	unsigned long begin, end;
 21};
 22
 23const char *stack_type_name(enum stack_type type);
 24int get_stack_info(unsigned long sp, struct task_struct *task,
 25		   struct stack_info *info, unsigned long *visit_mask);
 26
 27static inline bool on_stack(struct stack_info *info,
 28			    unsigned long addr, size_t len)
 29{
 30	if (info->type == STACK_TYPE_UNKNOWN)
 31		return false;
 32	if (addr + len < addr)
 33		return false;
 34	return addr >= info->begin && addr + len <= info->end;
 35}
 36
 37/*
 38 * Stack layout of a C stack frame.
 39 * Kernel uses the packed stack layout (-mpacked-stack).
 40 */
 41struct stack_frame {
 42	union {
 43		unsigned long empty[9];
 44		struct {
 45			unsigned long sie_control_block;
 46			unsigned long sie_savearea;
 47			unsigned long sie_reason;
 48			unsigned long sie_flags;
 49			unsigned long sie_control_block_phys;
 50		};
 51	};
 52	unsigned long gprs[10];
 53	unsigned long back_chain;
 54};
 55
 56/*
 57 * Unlike current_stack_pointer which simply contains the current value of %r15
 58 * current_frame_address() returns function stack frame address, which matches
 59 * %r15 upon function invocation. It may differ from %r15 later if function
 60 * allocates stack for local variables or new stack frame to call other
 61 * functions.
 62 */
 63#define current_frame_address()						\
 64	((unsigned long)__builtin_frame_address(0) -			\
 65	 offsetof(struct stack_frame, back_chain))
 66
 67static __always_inline unsigned long get_stack_pointer(struct task_struct *task,
 68						       struct pt_regs *regs)
 69{
 70	if (regs)
 71		return (unsigned long)kernel_stack_pointer(regs);
 72	if (task == current)
 73		return current_frame_address();
 74	return (unsigned long)task->thread.ksp;
 75}
 76
 77/*
 78 * To keep this simple mark register 2-6 as being changed (volatile)
 79 * by the called function, even though register 6 is saved/nonvolatile.
 80 */
 81#define CALL_FMT_0 "=&d" (r2)
 82#define CALL_FMT_1 "+&d" (r2)
 83#define CALL_FMT_2 CALL_FMT_1, "+&d" (r3)
 84#define CALL_FMT_3 CALL_FMT_2, "+&d" (r4)
 85#define CALL_FMT_4 CALL_FMT_3, "+&d" (r5)
 86#define CALL_FMT_5 CALL_FMT_4, "+&d" (r6)
 87
 88#define CALL_CLOBBER_5 "0", "1", "14", "cc", "memory"
 89#define CALL_CLOBBER_4 CALL_CLOBBER_5
 90#define CALL_CLOBBER_3 CALL_CLOBBER_4, "5"
 91#define CALL_CLOBBER_2 CALL_CLOBBER_3, "4"
 92#define CALL_CLOBBER_1 CALL_CLOBBER_2, "3"
 93#define CALL_CLOBBER_0 CALL_CLOBBER_1
 94
 95#define CALL_LARGS_0(...)						\
 96	long dummy = 0
 97#define CALL_LARGS_1(t1, a1)						\
 98	long arg1  = (long)(t1)(a1)
 99#define CALL_LARGS_2(t1, a1, t2, a2)					\
100	CALL_LARGS_1(t1, a1);						\
101	long arg2 = (long)(t2)(a2)
102#define CALL_LARGS_3(t1, a1, t2, a2, t3, a3)				\
103	CALL_LARGS_2(t1, a1, t2, a2);					\
104	long arg3 = (long)(t3)(a3)
105#define CALL_LARGS_4(t1, a1, t2, a2, t3, a3, t4, a4)			\
106	CALL_LARGS_3(t1, a1, t2, a2, t3, a3);				\
107	long arg4  = (long)(t4)(a4)
108#define CALL_LARGS_5(t1, a1, t2, a2, t3, a3, t4, a4, t5, a5)		\
109	CALL_LARGS_4(t1, a1, t2, a2, t3, a3, t4, a4);			\
110	long arg5 = (long)(t5)(a5)
111
112#define CALL_REGS_0							\
113	register long r2 asm("2") = dummy
114#define CALL_REGS_1							\
115	register long r2 asm("2") = arg1
116#define CALL_REGS_2							\
117	CALL_REGS_1;							\
118	register long r3 asm("3") = arg2
119#define CALL_REGS_3							\
120	CALL_REGS_2;							\
121	register long r4 asm("4") = arg3
122#define CALL_REGS_4							\
123	CALL_REGS_3;							\
124	register long r5 asm("5") = arg4
125#define CALL_REGS_5							\
126	CALL_REGS_4;							\
127	register long r6 asm("6") = arg5
128
129#define CALL_TYPECHECK_0(...)
130#define CALL_TYPECHECK_1(t, a, ...)					\
131	typecheck(t, a)
132#define CALL_TYPECHECK_2(t, a, ...)					\
133	CALL_TYPECHECK_1(__VA_ARGS__);					\
134	typecheck(t, a)
135#define CALL_TYPECHECK_3(t, a, ...)					\
136	CALL_TYPECHECK_2(__VA_ARGS__);					\
137	typecheck(t, a)
138#define CALL_TYPECHECK_4(t, a, ...)					\
139	CALL_TYPECHECK_3(__VA_ARGS__);					\
140	typecheck(t, a)
141#define CALL_TYPECHECK_5(t, a, ...)					\
142	CALL_TYPECHECK_4(__VA_ARGS__);					\
143	typecheck(t, a)
144
145#define CALL_PARM_0(...) void
146#define CALL_PARM_1(t, a, ...) t
147#define CALL_PARM_2(t, a, ...) t, CALL_PARM_1(__VA_ARGS__)
148#define CALL_PARM_3(t, a, ...) t, CALL_PARM_2(__VA_ARGS__)
149#define CALL_PARM_4(t, a, ...) t, CALL_PARM_3(__VA_ARGS__)
150#define CALL_PARM_5(t, a, ...) t, CALL_PARM_4(__VA_ARGS__)
151#define CALL_PARM_6(t, a, ...) t, CALL_PARM_5(__VA_ARGS__)
152
153/*
154 * Use call_on_stack() to call a function switching to a specified
155 * stack. Proper sign and zero extension of function arguments is
156 * done. Usage:
157 *
158 * rc = call_on_stack(nr, stack, rettype, fn, t1, a1, t2, a2, ...)
159 *
160 * - nr specifies the number of function arguments of fn.
161 * - stack specifies the stack to be used.
162 * - fn is the function to be called.
163 * - rettype is the return type of fn.
164 * - t1, a1, ... are pairs, where t1 must match the type of the first
165 *   argument of fn, t2 the second, etc. a1 is the corresponding
166 *   first function argument (not name), etc.
167 */
168#define call_on_stack(nr, stack, rettype, fn, ...)			\
169({									\
170	rettype (*__fn)(CALL_PARM_##nr(__VA_ARGS__)) = fn;		\
171	unsigned long frame = current_frame_address();			\
172	unsigned long __stack = stack;					\
173	unsigned long prev;						\
174	CALL_LARGS_##nr(__VA_ARGS__);					\
175	CALL_REGS_##nr;							\
176									\
177	CALL_TYPECHECK_##nr(__VA_ARGS__);				\
178	asm volatile(							\
179		"	lgr	%[_prev],15\n"				\
180		"	lg	15,%[_stack]\n"				\
181		"	stg	%[_frame],%[_bc](15)\n"			\
182		"	brasl	14,%[_fn]\n"				\
183		"	lgr	15,%[_prev]\n"				\
184		: [_prev] "=&d" (prev), CALL_FMT_##nr			\
185		: [_stack] "R" (__stack),				\
186		  [_bc] "i" (offsetof(struct stack_frame, back_chain)),	\
187		  [_frame] "d" (frame),					\
188		  [_fn] "X" (__fn) : CALL_CLOBBER_##nr);		\
189	(rettype)r2;							\
190})
191
192#define call_on_stack_noreturn(fn, stack)				\
193({									\
194	void (*__fn)(void) = fn;					\
195									\
196	asm volatile(							\
197		"	la	15,0(%[_stack])\n"			\
198		"	xc	%[_bc](8,15),%[_bc](15)\n"		\
199		"	brasl	14,%[_fn]\n"				\
200		::[_bc] "i" (offsetof(struct stack_frame, back_chain)),	\
201		  [_stack] "a" (stack), [_fn] "X" (__fn));		\
202	BUG();								\
203})
204
205#endif /* _ASM_S390_STACKTRACE_H */