x86/ftrace, x86/asm: Kill ftrace_caller_end label
One of ftrace_caller_end and ftrace_return is redundant so unify them. Rename ftrace_return to ftrace_epilogue to mean that everything after that label represents, like an afterword, work which happens *after* the ftrace call, e.g., the function graph tracer for one. Steve wants this to rather mean "[a]n event which reflects meaningfully on a recently ended conflict or struggle." I can imagine that ftrace can be a struggle sometimes. Anyway, beef up the comment about the code contents and layout before ftrace_epilogue label. Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1455612202-14414-4-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
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@ -697,9 +697,8 @@ static inline void tramp_free(void *tramp) { }
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#endif
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/* Defined as markers to the end of the ftrace default trampolines */
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extern void ftrace_caller_end(void);
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extern void ftrace_regs_caller_end(void);
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extern void ftrace_return(void);
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extern void ftrace_epilogue(void);
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extern void ftrace_caller_op_ptr(void);
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extern void ftrace_regs_caller_op_ptr(void);
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@ -746,7 +745,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
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op_offset = (unsigned long)ftrace_regs_caller_op_ptr;
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} else {
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start_offset = (unsigned long)ftrace_caller;
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end_offset = (unsigned long)ftrace_caller_end;
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end_offset = (unsigned long)ftrace_epilogue;
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op_offset = (unsigned long)ftrace_caller_op_ptr;
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}
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@ -754,7 +753,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
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/*
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* Allocate enough size to store the ftrace_caller code,
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* the jmp to ftrace_return, as well as the address of
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* the jmp to ftrace_epilogue, as well as the address of
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* the ftrace_ops this trampoline is used for.
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*/
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trampoline = alloc_tramp(size + MCOUNT_INSN_SIZE + sizeof(void *));
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@ -772,8 +771,8 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
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ip = (unsigned long)trampoline + size;
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/* The trampoline ends with a jmp to ftrace_return */
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jmp = ftrace_jmp_replace(ip, (unsigned long)ftrace_return);
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/* The trampoline ends with a jmp to ftrace_epilogue */
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jmp = ftrace_jmp_replace(ip, (unsigned long)ftrace_epilogue);
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memcpy(trampoline + size, jmp, MCOUNT_INSN_SIZE);
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/*
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@ -168,12 +168,14 @@ GLOBAL(ftrace_call)
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restore_mcount_regs
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/*
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* The copied trampoline must call ftrace_return as it
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* The copied trampoline must call ftrace_epilogue as it
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* still may need to call the function graph tracer.
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*
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* The code up to this label is copied into trampolines so
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* think twice before adding any new code or changing the
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* layout here.
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*/
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GLOBAL(ftrace_caller_end)
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GLOBAL(ftrace_return)
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GLOBAL(ftrace_epilogue)
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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GLOBAL(ftrace_graph_call)
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@ -244,14 +246,14 @@ GLOBAL(ftrace_regs_call)
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popfq
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/*
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* As this jmp to ftrace_return can be a short jump
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* As this jmp to ftrace_epilogue can be a short jump
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* it must not be copied into the trampoline.
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* The trampoline will add the code to jump
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* to the return.
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*/
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GLOBAL(ftrace_regs_caller_end)
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jmp ftrace_return
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jmp ftrace_epilogue
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END(ftrace_regs_caller)
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