ftrace/x86: Have save_mcount_regs macro also save stack frames if needed
The save_mcount_regs macro saves and restores the required mcount regs that need to be saved before calling C code. It is done for all the function hook utilities (static tracing, dynamic tracing, regs, function graph). When frame pointers are enabled, the ftrace trampolines need to set up frames and pointers such that a back trace (dump stack) can continue passed them. Currently, a separate macro is used (create_frame) to do this, but it's only done for the ftrace_caller and ftrace_reg_caller functions. It is not done for the static tracer or function graph tracing. Instead of having a separate macro doing the recording of the frames, have the save_mcount_regs perform this task. This also has all tracers saving the frame pointers when needed. Link: http://lkml.kernel.org/r/CA+55aFwF+qCGSKdGaEgW4p6N65GZ5_XTV=1NbtWDvxnd5yYLiw@mail.gmail.com Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1411262304010.3961@nanos Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (Red Hat)
Steven Rostedt
parent
85f6f0290c
commit
0687c36e45
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@ -21,8 +21,22 @@
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# define function_hook mcount
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#endif
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/* All cases save the original rbp (8 bytes) */
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#ifdef CONFIG_FRAME_POINTER
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# ifdef CC_USING_FENTRY
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/* Save parent and function stack frames (rip and rbp) */
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# define MCOUNT_FRAME_SIZE (8+16*2)
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# else
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/* Save just function stack frame (rip and rbp) */
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# define MCOUNT_FRAME_SIZE (8+16)
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# endif
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#else
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/* No need to save a stack frame */
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# define MCOUNT_FRAME_SIZE 8
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#endif /* CONFIG_FRAME_POINTER */
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/* Size of stack used to save mcount regs in save_mcount_regs */
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#define MCOUNT_REG_SIZE (SS+8)
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#define MCOUNT_REG_SIZE (SS+8 + MCOUNT_FRAME_SIZE)
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/*
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* gcc -pg option adds a call to 'mcount' in most functions.
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@ -42,10 +56,37 @@
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/* @added: the amount of stack added before calling this */
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.macro save_mcount_regs added=0
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/*
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* We add enough stack to save all regs.
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*/
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subq $MCOUNT_REG_SIZE, %rsp
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/* Always save the original rbp */
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pushq %rbp
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#ifdef CONFIG_FRAME_POINTER
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/*
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* Stack traces will stop at the ftrace trampoline if the frame pointer
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* is not set up properly. If fentry is used, we need to save a frame
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* pointer for the parent as well as the function traced, because the
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* fentry is called before the stack frame is set up, where as mcount
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* is called afterward.
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*/
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#ifdef CC_USING_FENTRY
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/* Save the parent pointer (skip orig rbp and our return address) */
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pushq \added+8*2(%rsp)
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pushq %rbp
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movq %rsp, %rbp
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/* Save the return address (now skip orig rbp, rbp and parent) */
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pushq \added+8*3(%rsp)
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#else
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/* Can't assume that rip is before this (unless added was zero) */
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pushq \added+8(%rsp)
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#endif
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pushq %rbp
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movq %rsp, %rbp
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#endif /* CONFIG_FRAME_POINTER */
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/*
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* We add enough stack to save all regs.
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*/
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subq $(MCOUNT_REG_SIZE - MCOUNT_FRAME_SIZE), %rsp
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movq %rax, RAX(%rsp)
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movq %rcx, RCX(%rsp)
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movq %rdx, RDX(%rsp)
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@ -53,6 +94,13 @@
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movq %rdi, RDI(%rsp)
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movq %r8, R8(%rsp)
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movq %r9, R9(%rsp)
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/*
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* Save the original RBP. Even though the mcount ABI does not
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* require this, it helps out callers.
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*/
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movq MCOUNT_REG_SIZE-8(%rsp), %rdx
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movq %rdx, RBP(%rsp)
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/* Move RIP to its proper location */
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movq MCOUNT_REG_SIZE+\added(%rsp), %rdi
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movq %rdi, RIP(%rsp)
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@ -66,7 +114,12 @@
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movq RDX(%rsp), %rdx
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movq RCX(%rsp), %rcx
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movq RAX(%rsp), %rax
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/* ftrace_regs_caller can modify %rbp */
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movq RBP(%rsp), %rbp
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addq $MCOUNT_REG_SIZE, %rsp
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.endm
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/* skip is set if stack has been adjusted */
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@ -84,7 +137,10 @@ GLOBAL(\trace_label)
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#ifdef CC_USING_FENTRY
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movq MCOUNT_REG_SIZE+8+\added(%rsp), %rsi
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#else
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movq 8+\added(%rbp), %rsi
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/* Need to grab the original %rbp */
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movq RBP(%rsp), %rsi
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/* Now parent address is 8 above original %rbp */
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movq 8(%rsi), %rsi
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#endif
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.endm
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@ -94,51 +150,14 @@ ENTRY(function_hook)
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retq
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END(function_hook)
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#ifdef CONFIG_FRAME_POINTER
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/*
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* Stack traces will stop at the ftrace trampoline if the frame pointer
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* is not set up properly. If fentry is used, we need to save a frame
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* pointer for the parent as well as the function traced, because the
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* fentry is called before the stack frame is set up, where as mcount
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* is called afterward.
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*/
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.macro create_frame parent rip
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#ifdef CC_USING_FENTRY
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pushq \parent
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pushq %rbp
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movq %rsp, %rbp
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#endif
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pushq \rip
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pushq %rbp
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movq %rsp, %rbp
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.endm
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.macro restore_frame
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#ifdef CC_USING_FENTRY
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addq $16, %rsp
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#endif
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popq %rbp
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addq $8, %rsp
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.endm
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#else
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.macro create_frame parent rip
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.endm
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.macro restore_frame
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.endm
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#endif /* CONFIG_FRAME_POINTER */
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ENTRY(ftrace_caller)
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ftrace_caller_setup ftrace_caller_op_ptr
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/* regs go into 4th parameter (but make it NULL) */
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movq $0, %rcx
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create_frame %rsi, %rdi
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GLOBAL(ftrace_call)
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call ftrace_stub
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restore_frame
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restore_mcount_regs
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/*
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@ -172,7 +191,6 @@ ENTRY(ftrace_regs_caller)
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movq %r12, R12(%rsp)
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movq %r11, R11(%rsp)
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movq %r10, R10(%rsp)
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movq %rbp, RBP(%rsp)
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movq %rbx, RBX(%rsp)
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/* Copy saved flags */
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movq MCOUNT_REG_SIZE(%rsp), %rcx
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@ -189,13 +207,9 @@ ENTRY(ftrace_regs_caller)
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/* regs go into 4th parameter */
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leaq (%rsp), %rcx
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create_frame %rsi, %rdi
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GLOBAL(ftrace_regs_call)
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call ftrace_stub
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restore_frame
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/* Copy flags back to SS, to restore them */
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movq EFLAGS(%rsp), %rax
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movq %rax, MCOUNT_REG_SIZE(%rsp)
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@ -210,7 +224,6 @@ GLOBAL(ftrace_regs_call)
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movq R13(%rsp), %r13
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movq R12(%rsp), %r12
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movq R10(%rsp), %r10
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movq RBP(%rsp), %rbp
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movq RBX(%rsp), %rbx
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restore_mcount_regs
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@ -269,8 +282,11 @@ ENTRY(ftrace_graph_caller)
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leaq MCOUNT_REG_SIZE+8(%rsp), %rdi
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movq $0, %rdx /* No framepointers needed */
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#else
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leaq 8(%rbp), %rdi
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movq (%rbp), %rdx
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/* Need to grab the original %rbp */
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movq RBP(%rsp), %rdx
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/* Now parent address is 8 above original %rbp */
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leaq 8(%rdx), %rdi
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movq (%rdx), %rdx
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#endif
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movq RIP(%rsp), %rsi
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subq $MCOUNT_INSN_SIZE, %rsi
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