/* SPDX-License-Identifier: GPL-2.0 */ /* Copyright (C) 2017 Andes Technology Corporation */ #include <linux/init.h> #include <linux/linkage.h> #include <asm/asm.h> #include <asm/csr.h> #include <asm/unistd.h> #include <asm/thread_info.h> #include <asm/asm-offsets.h> #include <asm-generic/export.h> #include <asm/ftrace.h> .text .macro SAVE_ABI_STATE addi sp, sp, -16 REG_S s0, 0*SZREG(sp) REG_S ra, 1*SZREG(sp) addi s0, sp, 16 .endm /* * The call to ftrace_return_to_handler would overwrite the return * register if a0 was not saved. */ .macro SAVE_RET_ABI_STATE addi sp, sp, -4*SZREG REG_S s0, 2*SZREG(sp) REG_S ra, 3*SZREG(sp) REG_S a0, 1*SZREG(sp) REG_S a1, 0*SZREG(sp) addi s0, sp, 4*SZREG .endm .macro RESTORE_ABI_STATE REG_L ra, 1*SZREG(sp) REG_L s0, 0*SZREG(sp) addi sp, sp, 16 .endm .macro RESTORE_RET_ABI_STATE REG_L ra, 3*SZREG(sp) REG_L s0, 2*SZREG(sp) REG_L a0, 1*SZREG(sp) REG_L a1, 0*SZREG(sp) addi sp, sp, 4*SZREG .endm ENTRY(ftrace_stub) #ifdef CONFIG_DYNAMIC_FTRACE .global MCOUNT_NAME .set MCOUNT_NAME, ftrace_stub #endif ret ENDPROC(ftrace_stub) #ifdef CONFIG_FUNCTION_GRAPH_TRACER ENTRY(return_to_handler) /* * On implementing the frame point test, the ideal way is to compare the * s0 (frame pointer, if enabled) on entry and the sp (stack pointer) on return. * However, the psABI of variable-length-argument functions does not allow this. * * So alternatively we check the *old* frame pointer position, that is, the * value stored in -16(s0) on entry, and the s0 on return. */ SAVE_RET_ABI_STATE mv a0, sp call ftrace_return_to_handler mv a2, a0 RESTORE_RET_ABI_STATE jalr a2 ENDPROC(return_to_handler) #endif #ifndef CONFIG_DYNAMIC_FTRACE ENTRY(MCOUNT_NAME) la t4, ftrace_stub #ifdef CONFIG_FUNCTION_GRAPH_TRACER la t0, ftrace_graph_return REG_L t1, 0(t0) bne t1, t4, do_ftrace_graph_caller la t3, ftrace_graph_entry REG_L t2, 0(t3) la t6, ftrace_graph_entry_stub bne t2, t6, do_ftrace_graph_caller #endif la t3, ftrace_trace_function REG_L t5, 0(t3) bne t5, t4, do_trace ret #ifdef CONFIG_FUNCTION_GRAPH_TRACER /* * A pseudo representation for the function graph tracer: * prepare_to_return(&ra_to_caller_of_caller, ra_to_caller) */ do_ftrace_graph_caller: addi a0, s0, -SZREG mv a1, ra #ifdef HAVE_FUNCTION_GRAPH_FP_TEST REG_L a2, -2*SZREG(s0) #endif SAVE_ABI_STATE call prepare_ftrace_return RESTORE_ABI_STATE ret #endif /* * A pseudo representation for the function tracer: * (*ftrace_trace_function)(ra_to_caller, ra_to_caller_of_caller) */ do_trace: REG_L a1, -SZREG(s0) mv a0, ra SAVE_ABI_STATE jalr t5 RESTORE_ABI_STATE ret ENDPROC(MCOUNT_NAME) #endif EXPORT_SYMBOL(MCOUNT_NAME)