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- /*
- * Split from entry_32.S
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
- */
- #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 */
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