99 lines
2 KiB
ArmAsm
99 lines
2 KiB
ArmAsm
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/*
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* Split from entry_32.S
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/magic.h>
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#include <asm/reg.h>
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#include <asm/ppc_asm.h>
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#include <asm/asm-offsets.h>
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#include <asm/ftrace.h>
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#include <asm/export.h>
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_GLOBAL(mcount)
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_GLOBAL(_mcount)
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/*
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* It is required that _mcount on PPC32 must preserve the
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* link register. But we have r0 to play with. We use r0
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* to push the return address back to the caller of mcount
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* into the ctr register, restore the link register and
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* then jump back using the ctr register.
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*/
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mflr r0
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mtctr r0
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lwz r0, 4(r1)
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mtlr r0
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bctr
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_GLOBAL(ftrace_caller)
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MCOUNT_SAVE_FRAME
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/* r3 ends up with link register */
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subi r3, r3, MCOUNT_INSN_SIZE
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.globl ftrace_call
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ftrace_call:
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bl ftrace_stub
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nop
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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.globl ftrace_graph_call
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ftrace_graph_call:
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b ftrace_graph_stub
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_GLOBAL(ftrace_graph_stub)
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#endif
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MCOUNT_RESTORE_FRAME
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/* old link register ends up in ctr reg */
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bctr
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EXPORT_SYMBOL(_mcount)
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_GLOBAL(ftrace_stub)
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blr
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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_GLOBAL(ftrace_graph_caller)
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/* load r4 with local address */
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lwz r4, 44(r1)
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subi r4, r4, MCOUNT_INSN_SIZE
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/* Grab the LR out of the caller stack frame */
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lwz r3,52(r1)
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bl prepare_ftrace_return
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nop
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/*
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* prepare_ftrace_return gives us the address we divert to.
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* Change the LR in the callers stack frame to this.
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*/
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stw r3,52(r1)
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MCOUNT_RESTORE_FRAME
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/* old link register ends up in ctr reg */
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bctr
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_GLOBAL(return_to_handler)
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/* need to save return values */
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stwu r1, -32(r1)
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stw r3, 20(r1)
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stw r4, 16(r1)
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stw r31, 12(r1)
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mr r31, r1
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bl ftrace_return_to_handler
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nop
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/* return value has real return address */
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mtlr r3
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lwz r3, 20(r1)
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lwz r4, 16(r1)
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lwz r31,12(r1)
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lwz r1, 0(r1)
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/* Jump back to real return address */
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blr
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#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
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