1 // SPDX-License-Identifier: GPL-2.0
3 * Code for tracing calls in Linux kernel.
4 * Copyright (C) 2009-2016 Helge Deller <deller@gmx.de>
6 * based on code for x86 which is:
7 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
9 * future possible enhancements:
10 * - add CONFIG_STACK_TRACER
13 #include <linux/init.h>
14 #include <linux/ftrace.h>
15 #include <linux/uaccess.h>
17 #include <asm/assembly.h>
18 #include <asm/sections.h>
19 #include <asm/ftrace.h>
20 #include <asm/patch.h>
22 #define __hot __attribute__ ((__section__ (".text.hot")))
24 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
26 * Hook the return address and push it in the stack of return addrs
27 * in current thread info.
29 static void __hot prepare_ftrace_return(unsigned long *parent,
30 unsigned long self_addr)
33 extern int parisc_return_to_handler;
35 if (unlikely(ftrace_graph_is_dead()))
38 if (unlikely(atomic_read(¤t->tracing_graph_pause)))
43 if (!function_graph_enter(old, self_addr, 0, NULL))
44 /* activate parisc_return_to_handler() as return point */
45 *parent = (unsigned long) &parisc_return_to_handler;
47 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
49 void notrace __hot ftrace_function_trampoline(unsigned long parent,
50 unsigned long self_addr,
51 unsigned long org_sp_gr3)
53 #ifndef CONFIG_DYNAMIC_FTRACE
54 extern ftrace_func_t ftrace_trace_function;
56 if (ftrace_trace_function != ftrace_stub)
57 ftrace_trace_function(self_addr, parent, NULL, NULL);
59 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
60 if (ftrace_graph_return != (trace_func_graph_ret_t) ftrace_stub ||
61 ftrace_graph_entry != ftrace_graph_entry_stub) {
62 unsigned long *parent_rp;
64 /* calculate pointer to %rp in stack */
65 parent_rp = (unsigned long *) (org_sp_gr3 - RP_OFFSET);
66 /* sanity check: parent_rp should hold parent */
67 if (*parent_rp != parent)
70 prepare_ftrace_return(parent_rp, self_addr);
76 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
77 int ftrace_enable_ftrace_graph_caller(void)
82 int ftrace_disable_ftrace_graph_caller(void)
88 #ifdef CONFIG_DYNAMIC_FTRACE
90 int __init ftrace_dyn_arch_init(void)
94 int ftrace_update_ftrace_func(ftrace_func_t func)
99 unsigned long ftrace_call_adjust(unsigned long addr)
101 return addr+(FTRACE_PATCHABLE_FUNCTION_SIZE-1)*4;
104 int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
106 u32 insn[FTRACE_PATCHABLE_FUNCTION_SIZE];
112 unsigned long addr2 =
113 (unsigned long)dereference_function_descriptor((void *)addr);
115 u32 ftrace_trampoline[] = {
116 0x73c10208, /* std,ma r1,100(sp) */
117 0x0c2110c1, /* ldd -10(r1),r1 */
118 0xe820d002, /* bve,n (r1) */
121 0xe83f1fd7, /* b,l,n .-14,r1 */
124 u32 ftrace_trampoline_unaligned[] = {
127 0x37de0200, /* ldo 100(sp),sp */
128 0x73c13e01, /* std r1,-100(sp) */
129 0x34213ff9, /* ldo -4(r1),r1 */
130 0x50213fc1, /* ldd -20(r1),r1 */
131 0xe820d002, /* bve,n (r1) */
132 0xe83f1fcf, /* b,l,n .-20,r1 */
135 BUILD_BUG_ON(ARRAY_SIZE(ftrace_trampoline_unaligned) >
136 FTRACE_PATCHABLE_FUNCTION_SIZE);
138 u32 ftrace_trampoline[] = {
140 0x6fc10080, /* stw,ma r1,40(sp) */
141 0x48213fd1, /* ldw -18(r1),r1 */
142 0xe820c002, /* bv,n r0(r1) */
143 0xe83f1fdf, /* b,l,n .-c,r1 */
147 BUILD_BUG_ON(ARRAY_SIZE(ftrace_trampoline) >
148 FTRACE_PATCHABLE_FUNCTION_SIZE);
150 size = sizeof(ftrace_trampoline);
151 tramp = ftrace_trampoline;
155 size = sizeof(ftrace_trampoline_unaligned);
156 tramp = ftrace_trampoline_unaligned;
160 ip = (void *)(rec->ip + 4 - size);
162 ret = probe_kernel_read(insn, ip, size);
166 for (i = 0; i < size / 4; i++) {
167 if (insn[i] != INSN_NOP)
171 __patch_text_multiple(ip, tramp, size);
175 int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
178 u32 insn[FTRACE_PATCHABLE_FUNCTION_SIZE];
181 for (i = 0; i < ARRAY_SIZE(insn); i++)
184 __patch_text_multiple((void *)rec->ip + 4 - sizeof(insn),