/* SPDX-License-Identifier: GPL-2.0 */
|
/*
|
* Copyright (C) 2017 Steven Rostedt, VMware Inc.
|
*/
|
|
#include <linux/linkage.h>
|
#include <asm/page_types.h>
|
#include <asm/segment.h>
|
#include <asm/export.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)
|
|
#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 %eax
|
pushl %edx
|
movl $0, %eax
|
call ftrace_return_to_handler
|
movl %eax, %ecx
|
popl %edx
|
popl %eax
|
JMP_NOSPEC ecx
|
#endif
|
