| // SPDX-License-Identifier: GPL-2.0 |
| |
| #include <linux/ftrace.h> |
| #include <linux/uaccess.h> |
| #include <asm/cacheflush.h> |
| |
| #ifndef CONFIG_DYNAMIC_FTRACE |
| extern void (*ftrace_trace_function)(unsigned long, unsigned long, |
| struct ftrace_ops*, struct pt_regs*); |
| extern void ftrace_graph_caller(void); |
| |
| noinline void __naked ftrace_stub(unsigned long ip, unsigned long parent_ip, |
| struct ftrace_ops *op, struct ftrace_regs *fregs) |
| { |
| __asm__ (""); /* avoid to optimize as pure function */ |
| } |
| |
| noinline void _mcount(unsigned long parent_ip) |
| { |
| /* save all state by the compiler prologue */ |
| |
| unsigned long ip = (unsigned long)__builtin_return_address(0); |
| |
| if (ftrace_trace_function != ftrace_stub) |
| ftrace_trace_function(ip - MCOUNT_INSN_SIZE, parent_ip, |
| NULL, NULL); |
| |
| #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
| if (ftrace_graph_return != (trace_func_graph_ret_t)ftrace_stub |
| || ftrace_graph_entry != ftrace_graph_entry_stub) |
| ftrace_graph_caller(); |
| #endif |
| |
| /* restore all state by the compiler epilogue */ |
| } |
| EXPORT_SYMBOL(_mcount); |
| |
| #else /* CONFIG_DYNAMIC_FTRACE */ |
| |
| noinline void __naked ftrace_stub(unsigned long ip, unsigned long parent_ip, |
| struct ftrace_ops *op, struct ftrace_regs *fregs) |
| { |
| __asm__ (""); /* avoid to optimize as pure function */ |
| } |
| |
| noinline void __naked _mcount(unsigned long parent_ip) |
| { |
| __asm__ (""); /* avoid to optimize as pure function */ |
| } |
| EXPORT_SYMBOL(_mcount); |
| |
| #define XSTR(s) STR(s) |
| #define STR(s) #s |
| void _ftrace_caller(unsigned long parent_ip) |
| { |
| /* save all state needed by the compiler prologue */ |
| |
| /* |
| * prepare arguments for real tracing function |
| * first arg : __builtin_return_address(0) - MCOUNT_INSN_SIZE |
| * second arg : parent_ip |
| */ |
| __asm__ __volatile__ ( |
| "move $r1, %0 \n\t" |
| "addi $r0, %1, #-" XSTR(MCOUNT_INSN_SIZE) "\n\t" |
| : |
| : "r" (parent_ip), "r" (__builtin_return_address(0))); |
| |
| /* a placeholder for the call to a real tracing function */ |
| __asm__ __volatile__ ( |
| "ftrace_call: \n\t" |
| "nop \n\t" |
| "nop \n\t" |
| "nop \n\t"); |
| |
| #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
| /* a placeholder for the call to ftrace_graph_caller */ |
| __asm__ __volatile__ ( |
| "ftrace_graph_call: \n\t" |
| "nop \n\t" |
| "nop \n\t" |
| "nop \n\t"); |
| #endif |
| /* restore all state needed by the compiler epilogue */ |
| } |
| |
| int __init ftrace_dyn_arch_init(void) |
| { |
| return 0; |
| } |
| |
| static unsigned long gen_sethi_insn(unsigned long addr) |
| { |
| unsigned long opcode = 0x46000000; |
| unsigned long imm = addr >> 12; |
| unsigned long rt_num = 0xf << 20; |
| |
| return ENDIAN_CONVERT(opcode | rt_num | imm); |
| } |
| |
| static unsigned long gen_ori_insn(unsigned long addr) |
| { |
| unsigned long opcode = 0x58000000; |
| unsigned long imm = addr & 0x0000fff; |
| unsigned long rt_num = 0xf << 20; |
| unsigned long ra_num = 0xf << 15; |
| |
| return ENDIAN_CONVERT(opcode | rt_num | ra_num | imm); |
| } |
| |
| static unsigned long gen_jral_insn(unsigned long addr) |
| { |
| unsigned long opcode = 0x4a000001; |
| unsigned long rt_num = 0x1e << 20; |
| unsigned long rb_num = 0xf << 10; |
| |
| return ENDIAN_CONVERT(opcode | rt_num | rb_num); |
| } |
| |
| static void ftrace_gen_call_insn(unsigned long *call_insns, |
| unsigned long addr) |
| { |
| call_insns[0] = gen_sethi_insn(addr); /* sethi $r15, imm20u */ |
| call_insns[1] = gen_ori_insn(addr); /* ori $r15, $r15, imm15u */ |
| call_insns[2] = gen_jral_insn(addr); /* jral $lp, $r15 */ |
| } |
| |
| static int __ftrace_modify_code(unsigned long pc, unsigned long *old_insn, |
| unsigned long *new_insn, bool validate) |
| { |
| unsigned long orig_insn[3]; |
| |
| if (validate) { |
| if (copy_from_kernel_nofault(orig_insn, (void *)pc, |
| MCOUNT_INSN_SIZE)) |
| return -EFAULT; |
| if (memcmp(orig_insn, old_insn, MCOUNT_INSN_SIZE)) |
| return -EINVAL; |
| } |
| |
| if (copy_to_kernel_nofault((void *)pc, new_insn, MCOUNT_INSN_SIZE)) |
| return -EPERM; |
| |
| return 0; |
| } |
| |
| static int ftrace_modify_code(unsigned long pc, unsigned long *old_insn, |
| unsigned long *new_insn, bool validate) |
| { |
| int ret; |
| |
| ret = __ftrace_modify_code(pc, old_insn, new_insn, validate); |
| if (ret) |
| return ret; |
| |
| flush_icache_range(pc, pc + MCOUNT_INSN_SIZE); |
| |
| return ret; |
| } |
| |
| int ftrace_update_ftrace_func(ftrace_func_t func) |
| { |
| unsigned long pc = (unsigned long)&ftrace_call; |
| unsigned long old_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP}; |
| unsigned long new_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP}; |
| |
| if (func != ftrace_stub) |
| ftrace_gen_call_insn(new_insn, (unsigned long)func); |
| |
| return ftrace_modify_code(pc, old_insn, new_insn, false); |
| } |
| |
| int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) |
| { |
| unsigned long pc = rec->ip; |
| unsigned long nop_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP}; |
| unsigned long call_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP}; |
| |
| ftrace_gen_call_insn(call_insn, addr); |
| |
| return ftrace_modify_code(pc, nop_insn, call_insn, true); |
| } |
| |
| int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, |
| unsigned long addr) |
| { |
| unsigned long pc = rec->ip; |
| unsigned long nop_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP}; |
| unsigned long call_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP}; |
| |
| ftrace_gen_call_insn(call_insn, addr); |
| |
| return ftrace_modify_code(pc, call_insn, nop_insn, true); |
| } |
| #endif /* CONFIG_DYNAMIC_FTRACE */ |
| |
| #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
| void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, |
| unsigned long frame_pointer) |
| { |
| unsigned long return_hooker = (unsigned long)&return_to_handler; |
| unsigned long old; |
| |
| if (unlikely(atomic_read(¤t->tracing_graph_pause))) |
| return; |
| |
| old = *parent; |
| |
| if (!function_graph_enter(old, self_addr, frame_pointer, NULL)) |
| *parent = return_hooker; |
| } |
| |
| noinline void ftrace_graph_caller(void) |
| { |
| unsigned long *parent_ip = |
| (unsigned long *)(__builtin_frame_address(2) - 4); |
| |
| unsigned long selfpc = |
| (unsigned long)(__builtin_return_address(1) - MCOUNT_INSN_SIZE); |
| |
| unsigned long frame_pointer = |
| (unsigned long)__builtin_frame_address(3); |
| |
| prepare_ftrace_return(parent_ip, selfpc, frame_pointer); |
| } |
| |
| extern unsigned long ftrace_return_to_handler(unsigned long frame_pointer); |
| void __naked return_to_handler(void) |
| { |
| __asm__ __volatile__ ( |
| /* save state needed by the ABI */ |
| "smw.adm $r0,[$sp],$r1,#0x0 \n\t" |
| |
| /* get original return address */ |
| "move $r0, $fp \n\t" |
| "bal ftrace_return_to_handler\n\t" |
| "move $lp, $r0 \n\t" |
| |
| /* restore state nedded by the ABI */ |
| "lmw.bim $r0,[$sp],$r1,#0x0 \n\t"); |
| } |
| |
| #ifdef CONFIG_DYNAMIC_FTRACE |
| extern unsigned long ftrace_graph_call; |
| |
| static int ftrace_modify_graph_caller(bool enable) |
| { |
| unsigned long pc = (unsigned long)&ftrace_graph_call; |
| unsigned long nop_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP}; |
| unsigned long call_insn[3] = {INSN_NOP, INSN_NOP, INSN_NOP}; |
| |
| ftrace_gen_call_insn(call_insn, (unsigned long)ftrace_graph_caller); |
| |
| if (enable) |
| return ftrace_modify_code(pc, nop_insn, call_insn, true); |
| else |
| return ftrace_modify_code(pc, call_insn, nop_insn, true); |
| } |
| |
| int ftrace_enable_ftrace_graph_caller(void) |
| { |
| return ftrace_modify_graph_caller(true); |
| } |
| |
| int ftrace_disable_ftrace_graph_caller(void) |
| { |
| return ftrace_modify_graph_caller(false); |
| } |
| #endif /* CONFIG_DYNAMIC_FTRACE */ |
| |
| #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ |
| |
| |
| #ifdef CONFIG_TRACE_IRQFLAGS |
| noinline void __trace_hardirqs_off(void) |
| { |
| trace_hardirqs_off(); |
| } |
| noinline void __trace_hardirqs_on(void) |
| { |
| trace_hardirqs_on(); |
| } |
| #endif /* CONFIG_TRACE_IRQFLAGS */ |
