| /* SPDX-License-Identifier: GPL-2.0 */ |
| /* |
| * Copyright (C) 2017 Steven Rostedt, VMware Inc. |
| */ |
| |
| #include <linux/export.h> |
| #include <linux/linkage.h> |
| #include <asm/page_types.h> |
| #include <asm/segment.h> |
| #include <asm/ftrace.h> |
| #include <asm/nospec-branch.h> |
| #include <asm/frame.h> |
| #include <asm/asm-offsets.h> |
| |
| #ifdef CONFIG_FRAME_POINTER |
| # define MCOUNT_FRAME 1 /* using frame = true */ |
| #else |
| # define MCOUNT_FRAME 0 /* using frame = false */ |
| #endif |
| |
| SYM_FUNC_START(__fentry__) |
| RET |
| SYM_FUNC_END(__fentry__) |
| EXPORT_SYMBOL(__fentry__) |
| |
| SYM_CODE_START(ftrace_caller) |
| |
| #ifdef CONFIG_FRAME_POINTER |
| /* |
| * Frame pointers are of ip followed by bp. |
| * Since fentry is an immediate jump, we are left with |
| * parent-ip, function-ip. We need to add a frame with |
| * parent-ip followed by ebp. |
| */ |
| pushl 4(%esp) /* parent ip */ |
| pushl %ebp |
| movl %esp, %ebp |
| pushl 2*4(%esp) /* function ip */ |
| |
| /* For mcount, the function ip is directly above */ |
| pushl %ebp |
| movl %esp, %ebp |
| #endif |
| pushl %eax |
| pushl %ecx |
| pushl %edx |
| pushl $0 /* Pass NULL as regs pointer */ |
| |
| #ifdef CONFIG_FRAME_POINTER |
| /* Load parent ebp into edx */ |
| movl 4*4(%esp), %edx |
| #else |
| /* There's no frame pointer, load the appropriate stack addr instead */ |
| lea 4*4(%esp), %edx |
| #endif |
| |
| movl (MCOUNT_FRAME+4)*4(%esp), %eax /* load the rip */ |
| /* Get the parent ip */ |
| movl 4(%edx), %edx /* edx has ebp */ |
| |
| movl function_trace_op, %ecx |
| subl $MCOUNT_INSN_SIZE, %eax |
| |
| .globl ftrace_call |
| ftrace_call: |
| call ftrace_stub |
| |
| addl $4, %esp /* skip NULL pointer */ |
| popl %edx |
| popl %ecx |
| popl %eax |
| #ifdef CONFIG_FRAME_POINTER |
| popl %ebp |
| addl $4,%esp /* skip function ip */ |
| popl %ebp /* this is the orig bp */ |
| addl $4, %esp /* skip parent ip */ |
| #endif |
| .Lftrace_ret: |
| #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
| .globl ftrace_graph_call |
| ftrace_graph_call: |
| jmp ftrace_stub |
| #endif |
| |
| /* This is weak to keep gas from relaxing the jumps */ |
| SYM_INNER_LABEL_ALIGN(ftrace_stub, SYM_L_WEAK) |
| RET |
| SYM_CODE_END(ftrace_caller) |
| |
| SYM_CODE_START(ftrace_regs_caller) |
| /* |
| * We're here from an mcount/fentry CALL, and the stack frame looks like: |
| * |
| * <previous context> |
| * RET-IP |
| * |
| * The purpose of this function is to call out in an emulated INT3 |
| * environment with a stack frame like: |
| * |
| * <previous context> |
| * gap / RET-IP |
| * gap |
| * gap |
| * gap |
| * pt_regs |
| * |
| * We do _NOT_ restore: ss, flags, cs, gs, fs, es, ds |
| */ |
| subl $3*4, %esp # RET-IP + 3 gaps |
| pushl %ss # ss |
| pushl %esp # points at ss |
| addl $5*4, (%esp) # make it point at <previous context> |
| pushfl # flags |
| pushl $__KERNEL_CS # cs |
| pushl 7*4(%esp) # ip <- RET-IP |
| pushl $0 # orig_eax |
| |
| pushl %gs |
| pushl %fs |
| pushl %es |
| pushl %ds |
| |
| pushl %eax |
| pushl %ebp |
| pushl %edi |
| pushl %esi |
| pushl %edx |
| pushl %ecx |
| pushl %ebx |
| |
| ENCODE_FRAME_POINTER |
| |
| movl PT_EIP(%esp), %eax # 1st argument: IP |
| subl $MCOUNT_INSN_SIZE, %eax |
| movl 21*4(%esp), %edx # 2nd argument: parent ip |
| movl function_trace_op, %ecx # 3rd argument: ftrace_pos |
| pushl %esp # 4th argument: pt_regs |
| |
| SYM_INNER_LABEL(ftrace_regs_call, SYM_L_GLOBAL) |
| call ftrace_stub |
| |
| addl $4, %esp # skip 4th argument |
| |
| /* place IP below the new SP */ |
| movl PT_OLDESP(%esp), %eax |
| movl PT_EIP(%esp), %ecx |
| movl %ecx, -4(%eax) |
| |
| /* place EAX below that */ |
| movl PT_EAX(%esp), %ecx |
| movl %ecx, -8(%eax) |
| |
| popl %ebx |
| popl %ecx |
| popl %edx |
| popl %esi |
| popl %edi |
| popl %ebp |
| |
| lea -8(%eax), %esp |
| popl %eax |
| |
| jmp .Lftrace_ret |
| SYM_CODE_END(ftrace_regs_caller) |
| |
| SYM_FUNC_START(ftrace_stub_direct_tramp) |
| CALL_DEPTH_ACCOUNT |
| RET |
| SYM_FUNC_END(ftrace_stub_direct_tramp) |
| |
| #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
| SYM_CODE_START(ftrace_graph_caller) |
| pushl %eax |
| pushl %ecx |
| pushl %edx |
| movl 3*4(%esp), %eax |
| /* Even with frame pointers, fentry doesn't have one here */ |
| lea 4*4(%esp), %edx |
| movl $0, %ecx |
| subl $MCOUNT_INSN_SIZE, %eax |
| call prepare_ftrace_return |
| popl %edx |
| popl %ecx |
| popl %eax |
| RET |
| SYM_CODE_END(ftrace_graph_caller) |
| |
| .globl return_to_handler |
| return_to_handler: |
| pushl $0 |
| pushl %edx |
| pushl %eax |
| movl %esp, %eax |
| call ftrace_return_to_handler |
| movl %eax, %ecx |
| popl %eax |
| popl %edx |
| addl $4, %esp # skip ebp |
| JMP_NOSPEC ecx |
| #endif |
