| 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
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| 2 | /* |
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| 3 | * LoongArch specific _mcount support |
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| 4 | * |
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| 5 | * Copyright (C) 2022 Loongson Technology Corporation Limited |
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| 6 | */ |
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| 7 | |
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| 8 | #include <linux/export.h> |
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| 9 | #include <asm/ftrace.h> |
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| 10 | #include <asm/regdef.h> |
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| 11 | #include <asm/stackframe.h> |
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| 12 | |
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| 13 | .text |
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| 14 | |
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| 15 | #define MCOUNT_S0_OFFSET (0) |
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| 16 | #define MCOUNT_RA_OFFSET (SZREG) |
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| 17 | #define MCOUNT_STACK_SIZE (2 * SZREG) |
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| 18 | |
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| 19 | .macro MCOUNT_SAVE_REGS |
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| 20 | PTR_ADDI sp, sp, -MCOUNT_STACK_SIZE |
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| 21 | PTR_S s0, sp, MCOUNT_S0_OFFSET |
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| 22 | PTR_S ra, sp, MCOUNT_RA_OFFSET |
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| 23 | move s0, a0 |
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| 24 | .endm |
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| 25 | |
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| 26 | .macro MCOUNT_RESTORE_REGS |
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| 27 | move a0, s0 |
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| 28 | PTR_L ra, sp, MCOUNT_RA_OFFSET |
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| 29 | PTR_L s0, sp, MCOUNT_S0_OFFSET |
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| 30 | PTR_ADDI sp, sp, MCOUNT_STACK_SIZE |
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| 31 | .endm |
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| 32 | |
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| 33 | SYM_FUNC_START(_mcount) |
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| 34 | la.pcrel t1, ftrace_stub |
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| 35 | la.pcrel t2, ftrace_trace_function /* Prepare t2 for (1) */ |
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| 36 | PTR_L t2, t2, 0 |
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| 37 | beq t1, t2, fgraph_trace |
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| 38 | |
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| 39 | MCOUNT_SAVE_REGS |
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| 40 | |
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| 41 | move a0, ra /* arg0: self return address */ |
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| 42 | move a1, s0 /* arg1: parent's return address */ |
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| 43 | jirl ra, t2, 0 /* (1) call *ftrace_trace_function */ |
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| 44 | |
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| 45 | MCOUNT_RESTORE_REGS |
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| 46 | |
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| 47 | fgraph_trace: |
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| 48 | #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
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| 49 | la.pcrel t1, ftrace_stub |
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| 50 | la.pcrel t3, ftrace_graph_return |
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| 51 | PTR_L t3, t3, 0 |
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| 52 | bne t1, t3, ftrace_graph_caller |
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| 53 | la.pcrel t1, ftrace_graph_entry_stub |
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| 54 | la.pcrel t3, ftrace_graph_entry |
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| 55 | PTR_L t3, t3, 0 |
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| 56 | bne t1, t3, ftrace_graph_caller |
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| 57 | #endif |
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| 58 | |
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| 59 | SYM_INNER_LABEL(ftrace_stub, SYM_L_GLOBAL) |
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| 60 | jr ra |
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| 61 | #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
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| 62 | SYM_INNER_LABEL(ftrace_graph_func, SYM_L_GLOBAL) |
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| 63 | bl ftrace_stub |
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| 64 | #endif |
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| 65 | SYM_FUNC_END(_mcount) |
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| 66 | EXPORT_SYMBOL(_mcount) |
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| 67 | |
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| 68 | #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
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| 69 | SYM_FUNC_START(ftrace_graph_caller) |
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| 70 | MCOUNT_SAVE_REGS |
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| 71 | |
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| 72 | PTR_ADDI a0, ra, -4 /* arg0: Callsite self return addr */ |
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| 73 | PTR_ADDI a1, sp, MCOUNT_STACK_SIZE /* arg1: Callsite sp */ |
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| 74 | move a2, s0 /* arg2: Callsite parent ra */ |
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| 75 | bl prepare_ftrace_return |
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| 76 | |
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| 77 | MCOUNT_RESTORE_REGS |
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| 78 | jr ra |
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| 79 | SYM_FUNC_END(ftrace_graph_caller) |
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| 80 | |
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| 81 | SYM_FUNC_START(return_to_handler) |
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| 82 | /* Save return value regs */ |
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| 83 | PTR_ADDI sp, sp, -PT_SIZE |
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| 84 | PTR_S a0, sp, PT_R4 |
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| 85 | PTR_S a1, sp, PT_R5 |
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| 86 | PTR_S zero, sp, PT_R22 |
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| 87 | |
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| 88 | move a0, sp |
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| 89 | bl ftrace_return_to_handler |
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| 90 | |
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| 91 | /* Restore the real parent address: a0 -> ra */ |
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| 92 | move ra, a0 |
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| 93 | |
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| 94 | /* Restore return value regs */ |
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| 95 | PTR_L a0, sp, PT_R4 |
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| 96 | PTR_L a1, sp, PT_R5 |
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| 97 | PTR_ADDI sp, sp, PT_SIZE |
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| 98 | |
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| 99 | jr ra |
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| 100 | SYM_FUNC_END(return_to_handler) |
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| 101 | #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ |
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| 102 | |
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