From 072de836f53be56a70cecf70b43ae43b7ce17376 Mon Sep 17 00:00:00 2001 From: hc <hc@nodka.com> Date: Mon, 11 Dec 2023 10:08:36 +0000 Subject: [PATCH] mk-rootfs.sh --- kernel/arch/arm64/kernel/entry-ftrace.S | 223 ++++++++++++++++++++++++++++++++++++++++++++----------- 1 files changed, 176 insertions(+), 47 deletions(-) diff --git a/kernel/arch/arm64/kernel/entry-ftrace.S b/kernel/arch/arm64/kernel/entry-ftrace.S index 295951f..67f68c9 100644 --- a/kernel/arch/arm64/kernel/entry-ftrace.S +++ b/kernel/arch/arm64/kernel/entry-ftrace.S @@ -1,18 +1,148 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ /* * arch/arm64/kernel/entry-ftrace.S * * Copyright (C) 2013 Linaro Limited * Author: AKASHI Takahiro <takahiro.akashi@linaro.org> - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. */ #include <linux/linkage.h> +#include <asm/asm-offsets.h> #include <asm/assembler.h> #include <asm/ftrace.h> #include <asm/insn.h> + +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS +/* + * Due to -fpatchable-function-entry=2, the compiler has placed two NOPs before + * the regular function prologue. For an enabled callsite, ftrace_init_nop() and + * ftrace_make_call() have patched those NOPs to: + * + * MOV X9, LR + * BL <entry> + * + * ... where <entry> is either ftrace_caller or ftrace_regs_caller. + * + * Each instrumented function follows the AAPCS, so here x0-x8 and x18-x30 are + * live (x18 holds the Shadow Call Stack pointer), and x9-x17 are safe to + * clobber. + * + * We save the callsite's context into a pt_regs before invoking any ftrace + * callbacks. So that we can get a sensible backtrace, we create a stack record + * for the callsite and the ftrace entry assembly. This is not sufficient for + * reliable stacktrace: until we create the callsite stack record, its caller + * is missing from the LR and existing chain of frame records. + */ + .macro ftrace_regs_entry, allregs=0 + /* Make room for pt_regs, plus a callee frame */ + sub sp, sp, #(S_FRAME_SIZE + 16) + + /* Save function arguments (and x9 for simplicity) */ + stp x0, x1, [sp, #S_X0] + stp x2, x3, [sp, #S_X2] + stp x4, x5, [sp, #S_X4] + stp x6, x7, [sp, #S_X6] + stp x8, x9, [sp, #S_X8] + + /* Optionally save the callee-saved registers, always save the FP */ + .if \allregs == 1 + stp x10, x11, [sp, #S_X10] + stp x12, x13, [sp, #S_X12] + stp x14, x15, [sp, #S_X14] + stp x16, x17, [sp, #S_X16] + stp x18, x19, [sp, #S_X18] + stp x20, x21, [sp, #S_X20] + stp x22, x23, [sp, #S_X22] + stp x24, x25, [sp, #S_X24] + stp x26, x27, [sp, #S_X26] + stp x28, x29, [sp, #S_X28] + .else + str x29, [sp, #S_FP] + .endif + + /* Save the callsite's SP and LR */ + add x10, sp, #(S_FRAME_SIZE + 16) + stp x9, x10, [sp, #S_LR] + + /* Save the PC after the ftrace callsite */ + str x30, [sp, #S_PC] + + /* Create a frame record for the callsite above pt_regs */ + stp x29, x9, [sp, #S_FRAME_SIZE] + add x29, sp, #S_FRAME_SIZE + + /* Create our frame record within pt_regs. */ + stp x29, x30, [sp, #S_STACKFRAME] + add x29, sp, #S_STACKFRAME + .endm + +SYM_CODE_START(ftrace_regs_caller) +#ifdef BTI_C + BTI_C +#endif + ftrace_regs_entry 1 + b ftrace_common +SYM_CODE_END(ftrace_regs_caller) + +SYM_CODE_START(ftrace_caller) +#ifdef BTI_C + BTI_C +#endif + ftrace_regs_entry 0 + b ftrace_common +SYM_CODE_END(ftrace_caller) + +SYM_CODE_START(ftrace_common) + sub x0, x30, #AARCH64_INSN_SIZE // ip (callsite's BL insn) + mov x1, x9 // parent_ip (callsite's LR) + ldr_l x2, function_trace_op // op + mov x3, sp // 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) // ftrace_graph_caller(); + nop // If enabled, this will be replaced + // "b ftrace_graph_caller" +#endif + +/* + * At the callsite x0-x8 and x19-x30 were live. Any C code will have preserved + * x19-x29 per the AAPCS, and we created frame records upon entry, so we need + * to restore x0-x8, x29, and x30. + */ +ftrace_common_return: + /* Restore function arguments */ + ldp x0, x1, [sp] + ldp x2, x3, [sp, #S_X2] + ldp x4, x5, [sp, #S_X4] + ldp x6, x7, [sp, #S_X6] + ldr x8, [sp, #S_X8] + + /* Restore the callsite's FP, LR, PC */ + ldr x29, [sp, #S_FP] + ldr x30, [sp, #S_LR] + ldr x9, [sp, #S_PC] + + /* Restore the callsite's SP */ + add sp, sp, #S_FRAME_SIZE + 16 + + ret x9 +SYM_CODE_END(ftrace_common) + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +SYM_CODE_START(ftrace_graph_caller) + ldr x0, [sp, #S_PC] + sub x0, x0, #AARCH64_INSN_SIZE // ip (callsite's BL insn) + add x1, sp, #S_LR // parent_ip (callsite's LR) + ldr x2, [sp, #S_FRAME_SIZE] // parent fp (callsite's FP) + bl prepare_ftrace_return + b ftrace_common_return +SYM_CODE_END(ftrace_graph_caller) +#endif + +#else /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */ /* * Gcc with -pg will put the following code in the beginning of each function: @@ -95,7 +225,7 @@ * - tracer function to probe instrumented function's entry, * - ftrace_graph_caller to set up an exit hook */ -ENTRY(_mcount) +SYM_FUNC_START(_mcount) mcount_enter ldr_l x2, ftrace_trace_function @@ -119,7 +249,9 @@ b.ne ftrace_graph_caller // ftrace_graph_caller(); #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ mcount_exit -ENDPROC(_mcount) +SYM_FUNC_END(_mcount) +EXPORT_SYMBOL(_mcount) +NOKPROBE(_mcount) #else /* CONFIG_DYNAMIC_FTRACE */ /* @@ -128,9 +260,11 @@ * and later on, NOP to branch to ftrace_caller() when enabled or branch to * NOP when disabled per-function base. */ -ENTRY(_mcount) +SYM_FUNC_START(_mcount) ret -ENDPROC(_mcount) +SYM_FUNC_END(_mcount) +EXPORT_SYMBOL(_mcount) +NOKPROBE(_mcount) /* * void ftrace_caller(unsigned long return_address) @@ -141,51 +275,27 @@ * - tracer function to probe instrumented function's entry, * - ftrace_graph_caller to set up an exit hook */ -ENTRY(ftrace_caller) +SYM_FUNC_START(ftrace_caller) mcount_enter mcount_get_pc0 x0 // function's pc mcount_get_lr x1 // function's lr - .global ftrace_call -ftrace_call: // tracer(pc, lr); +SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL) // tracer(pc, lr); nop // This will be replaced with "bl xxx" // where xxx can be any kind of tracer. #ifdef CONFIG_FUNCTION_GRAPH_TRACER - .global ftrace_graph_call -ftrace_graph_call: // ftrace_graph_caller(); +SYM_INNER_LABEL(ftrace_graph_call, SYM_L_GLOBAL) // ftrace_graph_caller(); nop // If enabled, this will be replaced // "b ftrace_graph_caller" #endif mcount_exit -ENDPROC(ftrace_caller) +SYM_FUNC_END(ftrace_caller) #endif /* CONFIG_DYNAMIC_FTRACE */ -ENTRY(ftrace_stub) - ret -ENDPROC(ftrace_stub) - #ifdef CONFIG_FUNCTION_GRAPH_TRACER - /* save return value regs*/ - .macro save_return_regs - sub sp, sp, #64 - stp x0, x1, [sp] - stp x2, x3, [sp, #16] - stp x4, x5, [sp, #32] - stp x6, x7, [sp, #48] - .endm - - /* restore return value regs*/ - .macro restore_return_regs - ldp x0, x1, [sp] - ldp x2, x3, [sp, #16] - ldp x4, x5, [sp, #32] - ldp x6, x7, [sp, #48] - add sp, sp, #64 - .endm - /* * void ftrace_graph_caller(void) * @@ -195,28 +305,47 @@ * the call stack in order to intercept instrumented function's return path * and run return_to_handler() later on its exit. */ -ENTRY(ftrace_graph_caller) - mcount_get_lr_addr x0 // pointer to function's saved lr - mcount_get_pc x1 // function's pc +SYM_FUNC_START(ftrace_graph_caller) + mcount_get_pc x0 // function's pc + mcount_get_lr_addr x1 // pointer to function's saved lr mcount_get_parent_fp x2 // parent's fp - bl prepare_ftrace_return // prepare_ftrace_return(&lr, pc, fp) + bl prepare_ftrace_return // prepare_ftrace_return(pc, &lr, fp) mcount_exit -ENDPROC(ftrace_graph_caller) +SYM_FUNC_END(ftrace_graph_caller) +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ +#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */ +SYM_FUNC_START(ftrace_stub) + ret +SYM_FUNC_END(ftrace_stub) + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER /* * void return_to_handler(void) * * Run ftrace_return_to_handler() before going back to parent. - * @fp is checked against the value passed by ftrace_graph_caller() - * only when HAVE_FUNCTION_GRAPH_FP_TEST is enabled. + * @fp is checked against the value passed by ftrace_graph_caller(). */ -ENTRY(return_to_handler) - save_return_regs +SYM_CODE_START(return_to_handler) + /* save return value regs */ + sub sp, sp, #64 + stp x0, x1, [sp] + stp x2, x3, [sp, #16] + stp x4, x5, [sp, #32] + stp x6, x7, [sp, #48] + mov x0, x29 // parent's fp bl ftrace_return_to_handler// addr = ftrace_return_to_hander(fp); mov x30, x0 // restore the original return address - restore_return_regs + + /* restore return value regs */ + ldp x0, x1, [sp] + ldp x2, x3, [sp, #16] + ldp x4, x5, [sp, #32] + ldp x6, x7, [sp, #48] + add sp, sp, #64 + ret -END(return_to_handler) +SYM_CODE_END(return_to_handler) #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ -- Gitblit v1.6.2