/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Code to prepare detour buffer for optprobes in Kernel.
*
* Copyright 2017, Anju T, IBM Corp.
*/
#include <asm/ppc_asm.h>
#include <asm/ptrace.h>
#include <asm/asm-offsets.h>
#ifdef CONFIG_PPC64
#define SAVE_30GPRS(base) SAVE_GPRS(2, 31, base)
#define REST_30GPRS(base) REST_GPRS(2, 31, base)
#define TEMPLATE_FOR_IMM_LOAD_INSNS nop; nop; nop; nop; nop
#else
#define SAVE_30GPRS(base) stmw r2, GPR2(base)
#define REST_30GPRS(base) lmw r2, GPR2(base)
#define TEMPLATE_FOR_IMM_LOAD_INSNS nop; nop; nop
#endif
#define OPT_SLOT_SIZE 65536
.balign 4
/*
* Reserve an area to allocate slots for detour buffer.
* This is part of .text section (rather than vmalloc area)
* as this needs to be within 32MB of the probed address.
*/
.
global optinsn_slot
optinsn_slot:
.space OPT_SLOT_SIZE
/*
* Optprobe template:
* This template gets copied into one of the slots in optinsn_slot
* and gets fixed up with real optprobe structures et al.
*/
.
global optprobe_template_entry
optprobe_template_entry:
/* Create an in-memory pt_regs */
PPC_STLU r1,-INT_FRAME_SIZE(r1)
SAVE_GPR(0,r1)
/* Save the previous SP into stack */
addi r0,r1,INT_FRAME_SIZE
PPC_STL r0,GPR1(r1)
SAVE_30GPRS(r1)
/* Save SPRS */
mfmsr r5
PPC_STL r5,_MSR(r1)
li r5,0x700
PPC_STL r5,_TRAP(r1)
li r5,0
PPC_STL r5,ORIG_GPR3(r1)
PPC_STL r5,RESULT(r1)
mfctr r5
PPC_STL r5,_CTR(r1)
mflr r5
PPC_STL r5,_LINK(r1)
mfspr r5,SPRN_XER
PPC_STL r5,_XER(r1)
mfcr r5
PPC_STL r5,_CCR(r1)
#ifdef CONFIG_PPC64
lbz r5,PACAIRQSOFTMASK(r13)
std r5,SOFTE(r1)
#endif
/*
* We may get here from a module, so load the kernel TOC in r2.
* The original TOC gets restored when pt_regs is restored
* further below.
*/
#ifdef CONFIG_PPC64
LOAD_PACA_TOC()
#endif
.
global optprobe_template_op_address
optprobe_template_op_address:
/*
* Parameters to optimized_callback():
* 1. optimized_kprobe structure in r3
*/
TEMPLATE_FOR_IMM_LOAD_INSNS
/* 2. pt_regs pointer in r4 */
addi r4,r1,STACK_INT_FRAME_REGS
.
global optprobe_template_call_handler
optprobe_template_call_handler:
/* Branch to optimized_callback() */
nop
/*
* Parameters for instruction emulation:
* 1. Pass SP in register r3.
*/
addi r3,r1,STACK_INT_FRAME_REGS
.
global optprobe_template_insn
optprobe_template_insn:
/* 2, Pass instruction to be emulated in r4 */
TEMPLATE_FOR_IMM_LOAD_INSNS
.
global optprobe_template_call_emulate
optprobe_template_call_emulate:
/* Branch to emulate_step() */
nop
/*
* All done.
* Now, restore the registers...
*/
PPC_LL r5,_MSR(r1)
mtmsr r5
PPC_LL r5,_CTR(r1)
mtctr r5
PPC_LL r5,_LINK(r1)
mtlr r5
PPC_LL r5,_XER(r1)
mtxer r5
PPC_LL r5,_CCR(r1)
mtcr r5
REST_GPR(0,r1)
REST_30GPRS(r1)
/* Restore the previous SP */
addi r1,r1,INT_FRAME_SIZE
.
global optprobe_template_ret
optprobe_template_ret:
/* ... and jump back from trampoline */
nop
.
global optprobe_template_end
optprobe_template_end:
