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commita1be9ccc57("function_graph: Support recording and printing the return value of function") introduced support for function graph return value tracing. Additionally, commita3ed4157b7("fgraph: Replace fgraph_ret_regs with ftrace_regs") further refactored and optimized the implementation, making `struct fgraph_ret_regs` unnecessary. This patch enables the above modifications for powerpc all, ensuring that function graph return value tracing is available on this architecture. In this patch we have redefined two functions: - 'ftrace_regs_get_return_value()' - the existing implementation on ppc returns -ve of return value based on some conditions not relevant to our patch. - 'ftrace_regs_get_frame_pointer()' - always returns 0 in current code . We also allocate stack space to equivalent of 'SWITCH_FRAME_SIZE', allowing us to directly use predefined offsets like 'GPR3' and 'GPR4' this keeps code clean and consistent with already defined offsets . After this patch, v6.14+ kernel can also be built with FPROBE on powerpc but there are a few other build and runtime dependencies for FPROBE to work properly. The next patch addresses them. Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com> Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Aditya Bodkhe <adityab1@linux.ibm.com> Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com> Link: https://patch.msgid.link/20250916044035.29033-1-adityab1@linux.ibm.com