1// SPDX-License-Identifier: GPL-2.0
  2#include <linux/spinlock.h>
  3#include <linux/hardirq.h>
  4#include <linux/ftrace.h>
  5#include <linux/percpu.h>
  6#include <linux/init.h>
  7#include <linux/list.h>
  8#include <trace/syscall.h>
  9
 10#include <asm/ftrace.h>
 11
 12#ifdef CONFIG_DYNAMIC_FTRACE
 13static const u32 ftrace_nop = 0x01000000;
 14
 15static u32 ftrace_call_replace(unsigned long ip, unsigned long addr)
 16{
 17	u32 call;
 18	s32 off;
 19
 20	off = ((s32)addr - (s32)ip);
 21	call = 0x40000000 | ((u32)off >> 2);
 22
 23	return call;
 24}
 25
 26static int ftrace_modify_code(unsigned long ip, u32 old, u32 new)
 27{
 28	u32 replaced;
 29	int faulted;
 30
 31	__asm__ __volatile__(
 32	"1:	cas	[%[ip]], %[old], %[new]\n"
 33	"	flush	%[ip]\n"
 34	"	mov	0, %[faulted]\n"
 35	"2:\n"
 36	"	.section .fixup,#alloc,#execinstr\n"
 37	"	.align	4\n"
 38	"3:	sethi	%%hi(2b), %[faulted]\n"
 39	"	jmpl	%[faulted] + %%lo(2b), %%g0\n"
 40	"	 mov	1, %[faulted]\n"
 41	"	.previous\n"
 42	"	.section __ex_table,\"a\"\n"
 43	"	.align	4\n"
 44	"	.word	1b, 3b\n"
 45	"	.previous\n"
 46	: "=r" (replaced), [faulted] "=r" (faulted)
 47	: [new] "0" (new), [old] "r" (old), [ip] "r" (ip)
 48	: "memory");
 49
 50	if (replaced != old && replaced != new)
 51		faulted = 2;
 52
 53	return faulted;
 54}
 55
 56int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr)
 57{
 58	unsigned long ip = rec->ip;
 59	u32 old, new;
 60
 61	old = ftrace_call_replace(ip, addr);
 62	new = ftrace_nop;
 63	return ftrace_modify_code(ip, old, new);
 64}
 65
 66int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
 67{
 68	unsigned long ip = rec->ip;
 69	u32 old, new;
 70
 71	old = ftrace_nop;
 72	new = ftrace_call_replace(ip, addr);
 73	return ftrace_modify_code(ip, old, new);
 74}
 75
 76int ftrace_update_ftrace_func(ftrace_func_t func)
 77{
 78	unsigned long ip = (unsigned long)(&ftrace_call);
 79	u32 old, new;
 80
 81	old = *(u32 *) &ftrace_call;
 82	new = ftrace_call_replace(ip, (unsigned long)func);
 83	return ftrace_modify_code(ip, old, new);
 84}
 85
 86int __init ftrace_dyn_arch_init(void)
 87{
 88	return 0;
 89}
 90#endif
 91
 92#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 93
 94#ifdef CONFIG_DYNAMIC_FTRACE
 95extern void ftrace_graph_call(void);
 96
 97int ftrace_enable_ftrace_graph_caller(void)
 98{
 99	unsigned long ip = (unsigned long)(&ftrace_graph_call);
100	u32 old, new;
101
102	old = *(u32 *) &ftrace_graph_call;
103	new = ftrace_call_replace(ip, (unsigned long) &ftrace_graph_caller);
104	return ftrace_modify_code(ip, old, new);
105}
106
107int ftrace_disable_ftrace_graph_caller(void)
108{
109	unsigned long ip = (unsigned long)(&ftrace_graph_call);
110	u32 old, new;
111
112	old = *(u32 *) &ftrace_graph_call;
113	new = ftrace_call_replace(ip, (unsigned long) &ftrace_stub);
114
115	return ftrace_modify_code(ip, old, new);
116}
117
118#endif /* !CONFIG_DYNAMIC_FTRACE */
119
120/*
121 * Hook the return address and push it in the stack of return addrs
122 * in current thread info.
123 */
124unsigned long prepare_ftrace_return(unsigned long parent,
125				    unsigned long self_addr,
126				    unsigned long frame_pointer)
127{
128	unsigned long return_hooker = (unsigned long) &return_to_handler;
129	struct ftrace_graph_ent trace;
130
131	if (unlikely(atomic_read(&current->tracing_graph_pause)))
132		return parent + 8UL;
133
134	trace.func = self_addr;
135	trace.depth = current->curr_ret_stack + 1;
136
137	/* Only trace if the calling function expects to */
138	if (!ftrace_graph_entry(&trace))
139		return parent + 8UL;
140
141	if (ftrace_push_return_trace(parent, self_addr, &trace.depth,
142				     frame_pointer, NULL) == -EBUSY)
143		return parent + 8UL;
144
145	return return_hooker;
146}
147#endif /* CONFIG_FUNCTION_GRAPH_TRACER */

  1// SPDX-License-Identifier: GPL-2.0
  2#include <linux/spinlock.h>
  3#include <linux/hardirq.h>
  4#include <linux/ftrace.h>
  5#include <linux/percpu.h>
  6#include <linux/init.h>
  7#include <linux/list.h>
  8#include <trace/syscall.h>
  9
 10#include <asm/ftrace.h>
 11
 12#ifdef CONFIG_DYNAMIC_FTRACE
 13static const u32 ftrace_nop = 0x01000000;
 14
 15static u32 ftrace_call_replace(unsigned long ip, unsigned long addr)
 16{
 17	u32 call;
 18	s32 off;
 19
 20	off = ((s32)addr - (s32)ip);
 21	call = 0x40000000 | ((u32)off >> 2);
 22
 23	return call;
 24}
 25
 26static int ftrace_modify_code(unsigned long ip, u32 old, u32 new)
 27{
 28	u32 replaced;
 29	int faulted;
 30
 31	__asm__ __volatile__(
 32	"1:	cas	[%[ip]], %[old], %[new]\n"
 33	"	flush	%[ip]\n"
 34	"	mov	0, %[faulted]\n"
 35	"2:\n"
 36	"	.section .fixup,#alloc,#execinstr\n"
 37	"	.align	4\n"
 38	"3:	sethi	%%hi(2b), %[faulted]\n"
 39	"	jmpl	%[faulted] + %%lo(2b), %%g0\n"
 40	"	 mov	1, %[faulted]\n"
 41	"	.previous\n"
 42	"	.section __ex_table,\"a\"\n"
 43	"	.align	4\n"
 44	"	.word	1b, 3b\n"
 45	"	.previous\n"
 46	: "=r" (replaced), [faulted] "=r" (faulted)
 47	: [new] "0" (new), [old] "r" (old), [ip] "r" (ip)
 48	: "memory");
 49
 50	if (replaced != old && replaced != new)
 51		faulted = 2;
 52
 53	return faulted;
 54}
 55
 56int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr)
 57{
 58	unsigned long ip = rec->ip;
 59	u32 old, new;
 60
 61	old = ftrace_call_replace(ip, addr);
 62	new = ftrace_nop;
 63	return ftrace_modify_code(ip, old, new);
 64}
 65
 66int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
 67{
 68	unsigned long ip = rec->ip;
 69	u32 old, new;
 70
 71	old = ftrace_nop;
 72	new = ftrace_call_replace(ip, addr);
 73	return ftrace_modify_code(ip, old, new);
 74}
 75
 76int ftrace_update_ftrace_func(ftrace_func_t func)
 77{
 78	unsigned long ip = (unsigned long)(&ftrace_call);
 79	u32 old, new;
 80
 81	old = *(u32 *) &ftrace_call;
 82	new = ftrace_call_replace(ip, (unsigned long)func);
 83	return ftrace_modify_code(ip, old, new);
 84}
 
 
 
 
 
 85#endif
 86
 87#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 88
 89#ifdef CONFIG_DYNAMIC_FTRACE
 90extern void ftrace_graph_call(void);
 91
 92int ftrace_enable_ftrace_graph_caller(void)
 93{
 94	unsigned long ip = (unsigned long)(&ftrace_graph_call);
 95	u32 old, new;
 96
 97	old = *(u32 *) &ftrace_graph_call;
 98	new = ftrace_call_replace(ip, (unsigned long) &ftrace_graph_caller);
 99	return ftrace_modify_code(ip, old, new);
100}
101
102int ftrace_disable_ftrace_graph_caller(void)
103{
104	unsigned long ip = (unsigned long)(&ftrace_graph_call);
105	u32 old, new;
106
107	old = *(u32 *) &ftrace_graph_call;
108	new = ftrace_call_replace(ip, (unsigned long) &ftrace_stub);
109
110	return ftrace_modify_code(ip, old, new);
111}
112
113#endif /* !CONFIG_DYNAMIC_FTRACE */
114
115/*
116 * Hook the return address and push it in the stack of return addrs
117 * in current thread info.
118 */
119unsigned long prepare_ftrace_return(unsigned long parent,
120				    unsigned long self_addr,
121				    unsigned long frame_pointer)
122{
123	unsigned long return_hooker = (unsigned long) &return_to_handler;
 
124
125	if (unlikely(atomic_read(&current->tracing_graph_pause)))
126		return parent + 8UL;
127
128	if (function_graph_enter(parent, self_addr, frame_pointer, NULL))
 
 
 
 
 
 
 
 
129		return parent + 8UL;
130
131	return return_hooker;
132}
133#endif /* CONFIG_FUNCTION_GRAPH_TRACER */