ftrace.h

  1/* SPDX-License-Identifier: GPL-2.0-only */
  2/*
  3 * arch/arm64/include/asm/ftrace.h
  4 *
  5 * Copyright (C) 2013 Linaro Limited
  6 * Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
  7 */
  8#ifndef __ASM_FTRACE_H
  9#define __ASM_FTRACE_H
 10
 11#include <asm/insn.h>
 12
 13#define HAVE_FUNCTION_GRAPH_FP_TEST
 14
 15#ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
 16#define ARCH_SUPPORTS_FTRACE_OPS 1
 17#else
 18#define MCOUNT_ADDR		((unsigned long)_mcount)
 19#endif
 20
 21/* The BL at the callsite's adjusted rec->ip */
 22#define MCOUNT_INSN_SIZE	AARCH64_INSN_SIZE
 23
 24#define FTRACE_PLT_IDX		0
 25#define NR_FTRACE_PLTS		1
 26
 27/*
 28 * Currently, gcc tends to save the link register after the local variables
 29 * on the stack. This causes the max stack tracer to report the function
 30 * frame sizes for the wrong functions. By defining
 31 * ARCH_FTRACE_SHIFT_STACK_TRACER, it will tell the stack tracer to expect
 32 * to find the return address on the stack after the local variables have
 33 * been set up.
 34 *
 35 * Note, this may change in the future, and we will need to deal with that
 36 * if it were to happen.
 37 */
 38#define ARCH_FTRACE_SHIFT_STACK_TRACER 1
 39
 40#ifndef __ASSEMBLER__
 41#include <linux/compat.h>
 42
 43extern void _mcount(unsigned long);
 44extern void *return_address(unsigned int);
 45
 46struct dyn_arch_ftrace {
 47	/* No extra data needed for arm64 */
 48};
 49
 50extern unsigned long ftrace_graph_call;
 51
 52extern void return_to_handler(void);
 53
 54unsigned long ftrace_call_adjust(unsigned long addr);
 55unsigned long arch_ftrace_get_symaddr(unsigned long fentry_ip);
 56#define ftrace_get_symaddr(fentry_ip) arch_ftrace_get_symaddr(fentry_ip)
 57
 58#ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
 59#define HAVE_ARCH_FTRACE_REGS
 60struct dyn_ftrace;
 61struct ftrace_ops;
 62struct ftrace_regs;
 63#define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))
 64
 65#define arch_ftrace_get_regs(regs) NULL
 66
 67/*
 68 * Note: sizeof(struct ftrace_regs) must be a multiple of 16 to ensure correct
 69 * stack alignment
 70 */
 71struct __arch_ftrace_regs {
 72	/* x0 - x8 */
 73	unsigned long regs[9];
 74
 75#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 76	unsigned long direct_tramp;
 77#else
 78	unsigned long __unused;
 79#endif
 80
 81	unsigned long fp;
 82	unsigned long lr;
 83
 84	unsigned long sp;
 85	unsigned long pc;
 86};
 87
 88static __always_inline unsigned long
 89ftrace_regs_get_instruction_pointer(const struct ftrace_regs *fregs)
 90{
 91	return arch_ftrace_regs(fregs)->pc;
 92}
 93
 94static __always_inline void
 95ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs,
 96				    unsigned long pc)
 97{
 98	arch_ftrace_regs(fregs)->pc = pc;
 99}
100
101static __always_inline unsigned long
102ftrace_regs_get_stack_pointer(const struct ftrace_regs *fregs)
103{
104	return arch_ftrace_regs(fregs)->sp;
105}
106
107static __always_inline unsigned long
108ftrace_regs_get_argument(struct ftrace_regs *fregs, unsigned int n)
109{
110	if (n < 8)
111		return arch_ftrace_regs(fregs)->regs[n];
112	return 0;
113}
114
115static __always_inline unsigned long
116ftrace_regs_get_return_value(const struct ftrace_regs *fregs)
117{
118	return arch_ftrace_regs(fregs)->regs[0];
119}
120
121static __always_inline void
122ftrace_regs_set_return_value(struct ftrace_regs *fregs,
123			     unsigned long ret)
124{
125	arch_ftrace_regs(fregs)->regs[0] = ret;
126}
127
128static __always_inline void
129ftrace_override_function_with_return(struct ftrace_regs *fregs)
130{
131	arch_ftrace_regs(fregs)->pc = arch_ftrace_regs(fregs)->lr;
132}
133
134static __always_inline unsigned long
135ftrace_regs_get_frame_pointer(const struct ftrace_regs *fregs)
136{
137	return arch_ftrace_regs(fregs)->fp;
138}
139
140static __always_inline unsigned long
141ftrace_regs_get_return_address(const struct ftrace_regs *fregs)
142{
143	return arch_ftrace_regs(fregs)->lr;
144}
145
146static __always_inline struct pt_regs *
147ftrace_partial_regs(const struct ftrace_regs *fregs, struct pt_regs *regs)
148{
149	struct __arch_ftrace_regs *afregs = arch_ftrace_regs(fregs);
150
151	memcpy(regs->regs, afregs->regs, sizeof(afregs->regs));
152	regs->sp = afregs->sp;
153	regs->pc = afregs->pc;
154	regs->regs[29] = afregs->fp;
155	regs->regs[30] = afregs->lr;
156	regs->pstate = PSR_MODE_EL1h;
157	return regs;
158}
159
160#define arch_ftrace_fill_perf_regs(fregs, _regs) do {		\
161		(_regs)->pc = arch_ftrace_regs(fregs)->pc;			\
162		(_regs)->regs[29] = arch_ftrace_regs(fregs)->fp;		\
163		(_regs)->sp = arch_ftrace_regs(fregs)->sp;			\
164		(_regs)->pstate = PSR_MODE_EL1h;		\
165	} while (0)
166
167int ftrace_regs_query_register_offset(const char *name);
168
169int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
170#define ftrace_init_nop ftrace_init_nop
171
172void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
173		       struct ftrace_ops *op, struct ftrace_regs *fregs);
174#define ftrace_graph_func ftrace_graph_func
175
176#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
177static inline void arch_ftrace_set_direct_caller(struct ftrace_regs *fregs,
178						 unsigned long addr)
179{
180	/*
181	 * The ftrace trampoline will return to this address instead of the
182	 * instrumented function.
183	 */
184	arch_ftrace_regs(fregs)->direct_tramp = addr;
185}
186#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
187
188#endif
189
190#define ftrace_return_address(n) return_address(n)
191
192/*
193 * Because AArch32 mode does not share the same syscall table with AArch64,
194 * tracing compat syscalls may result in reporting bogus syscalls or even
195 * hang-up, so just do not trace them.
196 * See kernel/trace/trace_syscalls.c
197 *
198 * x86 code says:
199 * If the user really wants these, then they should use the
200 * raw syscall tracepoints with filtering.
201 */
202#define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
203static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs)
204{
205	return is_compat_task();
206}
207
208#define ARCH_HAS_SYSCALL_MATCH_SYM_NAME
209
210static inline bool arch_syscall_match_sym_name(const char *sym,
211					       const char *name)
212{
213	/*
214	 * Since all syscall functions have __arm64_ prefix, we must skip it.
215	 * However, as we described above, we decided to ignore compat
216	 * syscalls, so we don't care about __arm64_compat_ prefix here.
217	 */
218	return !strcmp(sym + 8, name);
219}
220#endif /* ifndef __ASSEMBLER__ */
221
222#ifndef __ASSEMBLER__
223#ifdef CONFIG_FUNCTION_GRAPH_TRACER
224
225void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent,
226			   unsigned long frame_pointer);
227
228#endif /* ifdef CONFIG_FUNCTION_GRAPH_TRACER  */
229#endif
230
231#endif /* __ASM_FTRACE_H */