1/*
  2 * Split from entry_32.S
  3 *
  4 * This program is free software; you can redistribute it and/or
  5 * modify it under the terms of the GNU General Public License
  6 * as published by the Free Software Foundation; either version
  7 * 2 of the License, or (at your option) any later version.
  8 */
  9
 10#include <linux/magic.h>
 11#include <asm/reg.h>
 12#include <asm/ppc_asm.h>
 13#include <asm/asm-offsets.h>
 14#include <asm/ftrace.h>
 15#include <asm/export.h>
 16
 17#ifdef CONFIG_DYNAMIC_FTRACE
 18_GLOBAL(mcount)
 19_GLOBAL(_mcount)
 20	/*
 21	 * It is required that _mcount on PPC32 must preserve the
 22	 * link register. But we have r0 to play with. We use r0
 23	 * to push the return address back to the caller of mcount
 24	 * into the ctr register, restore the link register and
 25	 * then jump back using the ctr register.
 26	 */
 27	mflr	r0
 28	mtctr	r0
 29	lwz	r0, 4(r1)
 30	mtlr	r0
 31	bctr
 32
 33_GLOBAL(ftrace_caller)
 34	MCOUNT_SAVE_FRAME
 35	/* r3 ends up with link register */
 36	subi	r3, r3, MCOUNT_INSN_SIZE
 37.globl ftrace_call
 38ftrace_call:
 39	bl	ftrace_stub
 40	nop
 41#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 42.globl ftrace_graph_call
 43ftrace_graph_call:
 44	b	ftrace_graph_stub
 45_GLOBAL(ftrace_graph_stub)
 46#endif
 47	MCOUNT_RESTORE_FRAME
 48	/* old link register ends up in ctr reg */
 49	bctr
 50#else
 51_GLOBAL(mcount)
 52_GLOBAL(_mcount)
 53
 54	MCOUNT_SAVE_FRAME
 55
 56	subi	r3, r3, MCOUNT_INSN_SIZE
 57	LOAD_REG_ADDR(r5, ftrace_trace_function)
 58	lwz	r5,0(r5)
 59
 60	mtctr	r5
 61	bctrl
 62	nop
 63
 64#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 65	b	ftrace_graph_caller
 66#endif
 67	MCOUNT_RESTORE_FRAME
 68	bctr
 69#endif
 70EXPORT_SYMBOL(_mcount)
 71
 72_GLOBAL(ftrace_stub)
 73	blr
 74
 75#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 76_GLOBAL(ftrace_graph_caller)
 77	/* load r4 with local address */
 78	lwz	r4, 44(r1)
 79	subi	r4, r4, MCOUNT_INSN_SIZE
 80
 81	/* Grab the LR out of the caller stack frame */
 82	lwz	r3,52(r1)
 83
 84	bl	prepare_ftrace_return
 85	nop
 86
 87        /*
 88         * prepare_ftrace_return gives us the address we divert to.
 89         * Change the LR in the callers stack frame to this.
 90         */
 91	stw	r3,52(r1)
 92
 93	MCOUNT_RESTORE_FRAME
 94	/* old link register ends up in ctr reg */
 95	bctr
 96
 97_GLOBAL(return_to_handler)
 98	/* need to save return values */
 99	stwu	r1, -32(r1)
100	stw	r3, 20(r1)
101	stw	r4, 16(r1)
102	stw	r31, 12(r1)
103	mr	r31, r1
104
105	bl	ftrace_return_to_handler
106	nop
107
108	/* return value has real return address */
109	mtlr	r3
110
111	lwz	r3, 20(r1)
112	lwz	r4, 16(r1)
113	lwz	r31,12(r1)
114	lwz	r1, 0(r1)
115
116	/* Jump back to real return address */
117	blr
118#endif /* CONFIG_FUNCTION_GRAPH_TRACER */