diff options
Diffstat (limited to 'arch/x86/kernel/ftrace_32.S')
| -rw-r--r-- | arch/x86/kernel/ftrace_32.S | 202 |
1 files changed, 78 insertions, 124 deletions
diff --git a/arch/x86/kernel/ftrace_32.S b/arch/x86/kernel/ftrace_32.S index 4c8440de3355..f4e0c3361234 100644 --- a/arch/x86/kernel/ftrace_32.S +++ b/arch/x86/kernel/ftrace_32.S @@ -3,42 +3,29 @@ * 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/export.h> #include <asm/ftrace.h> #include <asm/nospec-branch.h> +#include <asm/frame.h> +#include <asm/asm-offsets.h> -#ifdef CC_USING_FENTRY -# define function_hook __fentry__ -EXPORT_SYMBOL(__fentry__) -#else -# define function_hook mcount -EXPORT_SYMBOL(mcount) -#endif - -#ifdef CONFIG_DYNAMIC_FTRACE - -/* mcount uses a frame pointer even if CONFIG_FRAME_POINTER is not set */ -#if !defined(CC_USING_FENTRY) || defined(CONFIG_FRAME_POINTER) -# define USING_FRAME_POINTER -#endif - -#ifdef USING_FRAME_POINTER +#ifdef CONFIG_FRAME_POINTER # define MCOUNT_FRAME 1 /* using frame = true */ #else # define MCOUNT_FRAME 0 /* using frame = false */ #endif -ENTRY(function_hook) - ret -END(function_hook) +SYM_FUNC_START(__fentry__) + RET +SYM_FUNC_END(__fentry__) +EXPORT_SYMBOL(__fentry__) -ENTRY(ftrace_caller) +SYM_CODE_START(ftrace_caller) -#ifdef USING_FRAME_POINTER -# ifdef CC_USING_FENTRY +#ifdef CONFIG_FRAME_POINTER /* * Frame pointers are of ip followed by bp. * Since fentry is an immediate jump, we are left with @@ -49,7 +36,7 @@ ENTRY(ftrace_caller) pushl %ebp movl %esp, %ebp pushl 2*4(%esp) /* function ip */ -# endif + /* For mcount, the function ip is directly above */ pushl %ebp movl %esp, %ebp @@ -59,7 +46,7 @@ ENTRY(ftrace_caller) pushl %edx pushl $0 /* Pass NULL as regs pointer */ -#ifdef USING_FRAME_POINTER +#ifdef CONFIG_FRAME_POINTER /* Load parent ebp into edx */ movl 4*4(%esp), %edx #else @@ -82,13 +69,11 @@ ftrace_call: popl %edx popl %ecx popl %eax -#ifdef USING_FRAME_POINTER +#ifdef CONFIG_FRAME_POINTER popl %ebp -# ifdef CC_USING_FENTRY addl $4,%esp /* skip function ip */ popl %ebp /* this is the orig bp */ addl $4, %esp /* skip parent ip */ -# endif #endif .Lftrace_ret: #ifdef CONFIG_FUNCTION_GRAPH_TRACER @@ -98,32 +83,44 @@ ftrace_graph_call: #endif /* This is weak to keep gas from relaxing the jumps */ -WEAK(ftrace_stub) - ret -END(ftrace_caller) +SYM_INNER_LABEL_ALIGN(ftrace_stub, SYM_L_WEAK) + RET +SYM_CODE_END(ftrace_caller) -ENTRY(ftrace_regs_caller) +SYM_CODE_START(ftrace_regs_caller) /* - * i386 does not save SS and ESP when coming from kernel. - * Instead, to get sp, ®s->sp is used (see ptrace.h). - * Unfortunately, that means eflags must be at the same location - * as the current return ip is. We move the return ip into the - * regs->ip location, and move flags into the return ip location. + * 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 */ - pushl $__KERNEL_CS - pushl 4(%esp) /* Save the return ip */ - pushl $0 /* Load 0 into orig_ax */ + 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 - - /* Get flags and place them into the return ip slot */ - pushf - popl %eax - movl %eax, 8*4(%esp) + pushl %eax pushl %ebp pushl %edi pushl %esi @@ -131,28 +128,27 @@ ENTRY(ftrace_regs_caller) pushl %ecx pushl %ebx - movl 12*4(%esp), %eax /* Load ip (1st parameter) */ - subl $MCOUNT_INSN_SIZE, %eax /* Adjust ip */ -#ifdef CC_USING_FENTRY - movl 15*4(%esp), %edx /* Load parent ip (2nd parameter) */ -#else - movl 0x4(%ebp), %edx /* Load parent ip (2nd parameter) */ -#endif - movl function_trace_op, %ecx /* Save ftrace_pos in 3rd parameter */ - pushl %esp /* Save pt_regs as 4th parameter */ + ENCODE_FRAME_POINTER -GLOBAL(ftrace_regs_call) + 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 pt_regs */ + addl $4, %esp # skip 4th argument - /* restore flags */ - push 14*4(%esp) - popf + /* place IP below the new SP */ + movl PT_OLDESP(%esp), %eax + movl PT_EIP(%esp), %ecx + movl %ecx, -4(%eax) - /* Move return ip back to its original location */ - movl 12*4(%esp), %eax - movl %eax, 14*4(%esp) + /* place EAX below that */ + movl PT_EAX(%esp), %ecx + movl %ecx, -8(%eax) popl %ebx popl %ecx @@ -160,88 +156,46 @@ GLOBAL(ftrace_regs_call) popl %esi popl %edi popl %ebp - popl %eax - popl %ds - popl %es - popl %fs - popl %gs - /* use lea to not affect flags */ - lea 3*4(%esp), %esp /* Skip orig_ax, ip and cs */ + lea -8(%eax), %esp + popl %eax jmp .Lftrace_ret -#else /* ! CONFIG_DYNAMIC_FTRACE */ +SYM_CODE_END(ftrace_regs_caller) -ENTRY(function_hook) - cmpl $__PAGE_OFFSET, %esp - jb ftrace_stub /* Paging not enabled yet? */ +SYM_FUNC_START(ftrace_stub_direct_tramp) + CALL_DEPTH_ACCOUNT + RET +SYM_FUNC_END(ftrace_stub_direct_tramp) - cmpl $ftrace_stub, ftrace_trace_function - jnz .Ltrace #ifdef CONFIG_FUNCTION_GRAPH_TRACER - cmpl $ftrace_stub, ftrace_graph_return - jnz ftrace_graph_caller - - cmpl $ftrace_graph_entry_stub, ftrace_graph_entry - jnz ftrace_graph_caller -#endif -.globl ftrace_stub -ftrace_stub: - ret - - /* taken from glibc */ -.Ltrace: - pushl %eax - pushl %ecx - pushl %edx - movl 0xc(%esp), %eax - movl 0x4(%ebp), %edx - subl $MCOUNT_INSN_SIZE, %eax - - movl ftrace_trace_function, %ecx - CALL_NOSPEC %ecx - - popl %edx - popl %ecx - popl %eax - jmp ftrace_stub -END(function_hook) -#endif /* CONFIG_DYNAMIC_FTRACE */ - -#ifdef CONFIG_FUNCTION_GRAPH_TRACER -ENTRY(ftrace_graph_caller) +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 */ -#ifdef CC_USING_FENTRY lea 4*4(%esp), %edx movl $0, %ecx -#else - lea 0x4(%ebp), %edx - movl (%ebp), %ecx -#endif subl $MCOUNT_INSN_SIZE, %eax call prepare_ftrace_return popl %edx popl %ecx popl %eax - ret -END(ftrace_graph_caller) + RET +SYM_CODE_END(ftrace_graph_caller) .globl return_to_handler return_to_handler: - pushl %eax - pushl %edx -#ifdef CC_USING_FENTRY - movl $0, %eax -#else - movl %ebp, %eax -#endif + subl $(PTREGS_SIZE), %esp + movl $0, PT_EBP(%esp) + movl %edx, PT_EDX(%esp) + movl %eax, PT_EAX(%esp) + movl %esp, %eax call ftrace_return_to_handler movl %eax, %ecx - popl %edx - popl %eax - JMP_NOSPEC %ecx + movl PT_EAX(%esp), %eax + movl PT_EDX(%esp), %edx + addl $(PTREGS_SIZE), %esp + JMP_NOSPEC ecx #endif |