/* SPDX-License-Identifier: GPL-2.0-or-later */ /* * Split from entry_32.S */ #include <linux/magic.h> #include <asm/reg.h> #include <asm/ppc_asm.h> #include <asm/asm-offsets.h> #include <asm/ftrace.h> #include <asm/export.h> _GLOBAL(mcount) _GLOBAL(_mcount) /* * It is required that _mcount on PPC32 must preserve the * link register. But we have r0 to play with. We use r0 * to push the return address back to the caller of mcount * into the ctr register, restore the link register and * then jump back using the ctr register. */ mflr r0 mtctr r0 lwz r0, 4(r1) mtlr r0 bctr _GLOBAL(ftrace_caller) MCOUNT_SAVE_FRAME /* r3 ends up with link register */ subi r3, r3, MCOUNT_INSN_SIZE .globl ftrace_call ftrace_call: bl ftrace_stub nop #ifdef [31mCONFIG_FUNCTION_GRAPH_TRACER[0m .globl ftrace_graph_call ftrace_graph_call: b ftrace_graph_stub _GLOBAL(ftrace_graph_stub) #endif MCOUNT_RESTORE_FRAME /* old link register ends up in ctr reg */ bctr EXPORT_SYMBOL(_mcount) _GLOBAL(ftrace_stub) blr #ifdef [31mCONFIG_FUNCTION_GRAPH_TRACER[0m _GLOBAL(ftrace_graph_caller) addi r5, r1, 48 /* load r4 with local address */ lwz r4, 44(r1) subi r4, r4, MCOUNT_INSN_SIZE /* Grab the LR out of the caller stack frame */ lwz r3,52(r1) bl prepare_ftrace_return nop /* * prepare_ftrace_return gives us the address we divert to. * Change the LR in the callers stack frame to this. */ stw r3,52(r1) MCOUNT_RESTORE_FRAME /* old link register ends up in ctr reg */ bctr _GLOBAL(return_to_handler) /* need to save return values */ stwu r1, -32(r1) stw r3, 20(r1) stw r4, 16(r1) stw r31, 12(r1) mr r31, r1 bl ftrace_return_to_handler nop /* return value has real return address */ mtlr r3 lwz r3, 20(r1) lwz r4, 16(r1) lwz r31,12(r1) lwz r1, 0(r1) /* Jump back to real return address */ blr #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ |