2017-02-08 17:50:51 +08:00
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/*
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* Code to prepare detour buffer for optprobes in Kernel.
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*
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* Copyright 2017, Anju T, IBM Corp.
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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 <asm/ppc_asm.h>
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#include <asm/ptrace.h>
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#include <asm/asm-offsets.h>
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#define OPT_SLOT_SIZE 65536
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.balign 4
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/*
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* Reserve an area to allocate slots for detour buffer.
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* This is part of .text section (rather than vmalloc area)
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* as this needs to be within 32MB of the probed address.
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*/
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.global optinsn_slot
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optinsn_slot:
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.space OPT_SLOT_SIZE
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/*
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* Optprobe template:
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* This template gets copied into one of the slots in optinsn_slot
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* and gets fixed up with real optprobe structures et al.
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*/
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.global optprobe_template_entry
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optprobe_template_entry:
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/* Create an in-memory pt_regs */
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stdu r1,-INT_FRAME_SIZE(r1)
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SAVE_GPR(0,r1)
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/* Save the previous SP into stack */
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addi r0,r1,INT_FRAME_SIZE
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std r0,GPR1(r1)
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SAVE_10GPRS(2,r1)
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SAVE_10GPRS(12,r1)
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SAVE_10GPRS(22,r1)
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/* Save SPRS */
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mfmsr r5
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std r5,_MSR(r1)
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li r5,0x700
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std r5,_TRAP(r1)
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li r5,0
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std r5,ORIG_GPR3(r1)
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std r5,RESULT(r1)
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mfctr r5
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std r5,_CTR(r1)
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mflr r5
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std r5,_LINK(r1)
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mfspr r5,SPRN_XER
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std r5,_XER(r1)
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mfcr r5
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std r5,_CCR(r1)
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lbz r5,PACASOFTIRQEN(r13)
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std r5,SOFTE(r1)
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2017-02-21 23:00:47 +08:00
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/*
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* We may get here from a module, so load the kernel TOC in r2.
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* The original TOC gets restored when pt_regs is restored
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* further below.
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*/
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ld r2,PACATOC(r13)
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2017-02-08 17:50:51 +08:00
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.global optprobe_template_op_address
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optprobe_template_op_address:
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/*
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* Parameters to optimized_callback():
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* 1. optimized_kprobe structure in r3
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*/
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nop
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nop
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nop
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nop
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nop
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/* 2. pt_regs pointer in r4 */
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addi r4,r1,STACK_FRAME_OVERHEAD
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.global optprobe_template_call_handler
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optprobe_template_call_handler:
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/* Branch to optimized_callback() */
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nop
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/*
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* Parameters for instruction emulation:
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* 1. Pass SP in register r3.
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*/
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addi r3,r1,STACK_FRAME_OVERHEAD
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.global optprobe_template_insn
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optprobe_template_insn:
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/* 2, Pass instruction to be emulated in r4 */
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nop
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nop
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.global optprobe_template_call_emulate
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optprobe_template_call_emulate:
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/* Branch to emulate_step() */
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nop
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/*
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* All done.
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* Now, restore the registers...
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*/
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ld r5,_MSR(r1)
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mtmsr r5
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ld r5,_CTR(r1)
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mtctr r5
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ld r5,_LINK(r1)
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mtlr r5
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ld r5,_XER(r1)
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mtxer r5
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ld r5,_CCR(r1)
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mtcr r5
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REST_GPR(0,r1)
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REST_10GPRS(2,r1)
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REST_10GPRS(12,r1)
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REST_10GPRS(22,r1)
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/* Restore the previous SP */
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addi r1,r1,INT_FRAME_SIZE
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.global optprobe_template_ret
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optprobe_template_ret:
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/* ... and jump back from trampoline */
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nop
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.global optprobe_template_end
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optprobe_template_end:
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