Messages in this thread | | | Date | Wed, 15 Mar 2023 14:49:11 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v4 1/2] function_graph: Support recording and printing the return value of function |
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On Wed, Mar 15, 2023 at 06:39:10AM -0700, Donglin Peng wrote: > diff --git a/arch/x86/kernel/ftrace_32.S b/arch/x86/kernel/ftrace_32.S > index a0ed0e4a2c0c..44a773d9de82 100644 > --- a/arch/x86/kernel/ftrace_32.S > +++ b/arch/x86/kernel/ftrace_32.S > @@ -184,6 +184,10 @@ SYM_CODE_END(ftrace_graph_caller) > return_to_handler: > pushl %eax > pushl %edx > +#ifdef CONFIG_FUNCTION_GRAPH_RETVAL > + /* Pass the function return value to ftrace_return_to_handler*/ > + movl %eax, %edx > +#endif > movl $0, %eax > call ftrace_return_to_handler > movl %eax, %ecx > diff --git a/arch/x86/kernel/ftrace_64.S b/arch/x86/kernel/ftrace_64.S > index 1265ad519249..35ac9c58dc77 100644 > --- a/arch/x86/kernel/ftrace_64.S > +++ b/arch/x86/kernel/ftrace_64.S > @@ -348,6 +348,10 @@ SYM_CODE_START(return_to_handler) > movq %rax, (%rsp) > movq %rdx, 8(%rsp) > movq %rbp, %rdi > +#ifdef CONFIG_FUNCTION_GRAPH_RETVAL > + /* Pass the function return value to ftrace_return_to_handler */ > + movq %rax, %rsi > +#endif > > call ftrace_return_to_handler
What about the case of double register return values (when the value is returned in the A,D pair) ?
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