/* SPDX-License-Identifier: GPL-2.0 */ /* * Copyright (C) 2022 Loongson Technology Corporation Limited */ #include <asm/ftrace.h> #include <asm/regdef.h> #include <asm/stackframe.h> .text /* * Due to -fpatchable-function-entry=2: the compiler inserted 2 NOPs before the * regular C function prologue. When PC arrived here, the last 2 instructions * are as follows: * move t0, ra * bl callsite (for modules, callsite is a tramplione) * * modules trampoline is as follows: * lu12i.w t1, callsite[31:12] * lu32i.d t1, callsite[51:32] * lu52i.d t1, t1, callsite[63:52] * jirl zero, t1, callsite[11:0] >> 2 * * See arch/loongarch/kernel/ftrace_dyn.c for details. Here, pay attention to * that the T series regs are available and safe because each C functions * follows the LoongArch's psABI as well. */ .macro ftrace_regs_entry allregs=0 PTR_ADDI sp, sp, -PT_SIZE PTR_S t0, sp, PT_R1 /* Save parent ra at PT_R1(RA) */ PTR_S a0, sp, PT_R4 PTR_S a1, sp, PT_R5 PTR_S a2, sp, PT_R6 PTR_S a3, sp, PT_R7 PTR_S a4, sp, PT_R8 PTR_S a5, sp, PT_R9 PTR_S a6, sp, PT_R10 PTR_S a7, sp, PT_R11 PTR_S fp, sp, PT_R22 .if \allregs PTR_S tp, sp, PT_R2 PTR_S t0, sp, PT_R12 PTR_S t2, sp, PT_R14 PTR_S t3, sp, PT_R15 PTR_S t4, sp, PT_R16 PTR_S t5, sp, PT_R17 PTR_S t6, sp, PT_R18 PTR_S t7, sp, PT_R19 PTR_S t8, sp, PT_R20 PTR_S u0, sp, PT_R21 PTR_S s0, sp, PT_R23 PTR_S s1, sp, PT_R24 PTR_S s2, sp, PT_R25 PTR_S s3, sp, PT_R26 PTR_S s4, sp, PT_R27 PTR_S s5, sp, PT_R28 PTR_S s6, sp, PT_R29 PTR_S s7, sp, PT_R30 PTR_S s8, sp, PT_R31 /* Clear it for later use as a flag sometimes. */ PTR_S zero, sp, PT_R0 .endif PTR_S ra, sp, PT_ERA /* Save trace function ra at PT_ERA */ move t1, zero PTR_S t1, sp, PT_R13 PTR_ADDI t8, sp, PT_SIZE PTR_S t8, sp, PT_R3 .endm SYM_FUNC_START(ftrace_stub) jr ra SYM_FUNC_END(ftrace_stub) SYM_CODE_START(ftrace_common) PTR_ADDI a0, ra, -8 /* arg0: ip */ move a1, t0 /* arg1: parent_ip */ la.pcrel t1, function_trace_op PTR_L a2, t1, 0 /* arg2: op */ move a3, sp /* arg3: regs */ SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL) bl ftrace_stub #ifdef CONFIG_FUNCTION_GRAPH_TRACER SYM_INNER_LABEL(ftrace_graph_call, SYM_L_GLOBAL) nop /* b ftrace_graph_caller */ #endif /* * As we didn't use S series regs in this assmembly code and all calls * are C function which will save S series regs by themselves, there is * no need to restore S series regs. The T series is available and safe * at the callsite, so there is no need to restore the T series regs. */ ftrace_common_return: PTR_L ra, sp, PT_R1 PTR_L a0, sp, PT_R4 PTR_L a1, sp, PT_R5 PTR_L a2, sp, PT_R6 PTR_L a3, sp, PT_R7 PTR_L a4, sp, PT_R8 PTR_L a5, sp, PT_R9 PTR_L a6, sp, PT_R10 PTR_L a7, sp, PT_R11 PTR_L fp, sp, PT_R22 PTR_L t0, sp, PT_ERA PTR_L t1, sp, PT_R13 PTR_ADDI sp, sp, PT_SIZE bnez t1, .Ldirect jr t0 .Ldirect: jr t1 SYM_CODE_END(ftrace_common) SYM_CODE_START(ftrace_caller) ftrace_regs_entry allregs=0 b ftrace_common SYM_CODE_END(ftrace_caller) #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS SYM_CODE_START(ftrace_regs_caller) ftrace_regs_entry allregs=1 b ftrace_common SYM_CODE_END(ftrace_regs_caller) #endif #ifdef CONFIG_FUNCTION_GRAPH_TRACER SYM_CODE_START(ftrace_graph_caller) PTR_L a0, sp, PT_ERA PTR_ADDI a0, a0, -8 /* arg0: self_addr */ PTR_ADDI a1, sp, PT_R1 /* arg1: parent */ bl prepare_ftrace_return b ftrace_common_return SYM_CODE_END(ftrace_graph_caller) SYM_CODE_START(return_to_handler) /* Save return value regs */ PTR_ADDI sp, sp, -FGRET_REGS_SIZE PTR_S a0, sp, FGRET_REGS_A0 PTR_S a1, sp, FGRET_REGS_A1 PTR_S zero, sp, FGRET_REGS_FP move a0, sp bl ftrace_return_to_handler move ra, a0 /* Restore return value regs */ PTR_L a0, sp, FGRET_REGS_A0 PTR_L a1, sp, FGRET_REGS_A1 PTR_ADDI sp, sp, FGRET_REGS_SIZE jr ra SYM_CODE_END(return_to_handler) #endif #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS SYM_CODE_START(ftrace_stub_direct_tramp) jr t0 SYM_CODE_END(ftrace_stub_direct_tramp) #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */