1 // SPDX-License-Identifier: GPL-2.0-only
15 #include <asm/debug-monitors.h>
24 static int ftrace_modify_code(unsigned long pc, u32 old, u32 new,  in ftrace_modify_code()  argument
32 	 * could cause us to read or write to someplace that could cause harm.  in ftrace_modify_code()
38 		if (aarch64_insn_read((void *)pc, &replaced))  in ftrace_modify_code()
39 			return -EFAULT;  in ftrace_modify_code()
42 			return -EINVAL;  in ftrace_modify_code()
44 	if (aarch64_insn_patch_text_nosync((void *)pc, new))  in ftrace_modify_code()
45 		return -EPERM;  in ftrace_modify_code()
55 	unsigned long pc;  in ftrace_update_ftrace_func()  local
58 	pc = (unsigned long)&ftrace_call;  in ftrace_update_ftrace_func()
59 	new = aarch64_insn_gen_branch_imm(pc, (unsigned long)func,  in ftrace_update_ftrace_func()
62 	return ftrace_modify_code(pc, 0, new, false);  in ftrace_update_ftrace_func()
70 	unsigned long pc = rec->ip;  in ftrace_make_call()  local
72 	long offset = (long)pc - (long)addr;  in ftrace_make_call()
74 	if (offset < -SZ_128M || offset >= SZ_128M) {  in ftrace_make_call()
90 		mod = __module_text_address(pc);  in ftrace_make_call()
94 			return -EINVAL;  in ftrace_make_call()
109 		dst = mod->arch.ftrace_trampoline;  in ftrace_make_call()
114 				return -EINVAL;  in ftrace_make_call()
126 			 * Neoverse-N1 erratum #1542419 does require one  in ftrace_make_call()
130 			 * certainly not a fast-path.  in ftrace_make_call()
137 		return -EINVAL;  in ftrace_make_call()
142 	new = aarch64_insn_gen_branch_imm(pc, addr, AARCH64_INSN_BRANCH_LINK);  in ftrace_make_call()
144 	return ftrace_modify_code(pc, old, new, true);  in ftrace_make_call()
153 	unsigned long pc = rec->ip;  in ftrace_make_nop()  local
156 	long offset = (long)pc - (long)addr;  in ftrace_make_nop()
158 	if (offset < -SZ_128M || offset >= SZ_128M) {  in ftrace_make_nop()
164 		 * dealing with an out-of-range condition, we can assume it  in ftrace_make_nop()
169 			mod = __module_text_address(pc);  in ftrace_make_nop()
173 				return -EINVAL;  in ftrace_make_nop()
183 		if (aarch64_insn_read((void *)pc, &replaced))  in ftrace_make_nop()
184 			return -EFAULT;  in ftrace_make_nop()
187 		    !within_module(pc + aarch64_get_branch_offset(replaced),  in ftrace_make_nop()
189 			return -EINVAL;  in ftrace_make_nop()
193 		return -EINVAL;  in ftrace_make_nop()
196 		old = aarch64_insn_gen_branch_imm(pc, addr,  in ftrace_make_nop()
202 	return ftrace_modify_code(pc, old, new, validate);  in ftrace_make_nop()
232 	if (unlikely(atomic_read(&current->tracing_graph_pause)))  in prepare_ftrace_return()
237 	 * No protection against faulting at *parent, which may be seen  in prepare_ftrace_return()
253 	unsigned long pc = (unsigned long)&ftrace_graph_call;  in ftrace_modify_graph_caller()  local
256 	branch = aarch64_insn_gen_branch_imm(pc,  in ftrace_modify_graph_caller()
262 		return ftrace_modify_code(pc, nop, branch, true);  in ftrace_modify_graph_caller()
264 		return ftrace_modify_code(pc, branch, nop, true);  in ftrace_modify_graph_caller()