| /* 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 CONFIG_FUNCTION_GRAPH_TRACER |
| .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 CONFIG_FUNCTION_GRAPH_TRACER |
| _GLOBAL(ftrace_graph_caller) |
| /* 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 */ |
