cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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optprobes_head.S (2997B)

      1/* SPDX-License-Identifier: GPL-2.0-or-later */
      2/*
      3 * Code to prepare detour buffer for optprobes in Kernel.
      4 *
      5 * Copyright 2017, Anju T, IBM Corp.
      6 */
      7
      8#include <asm/ppc_asm.h>
      9#include <asm/ptrace.h>
     10#include <asm/asm-offsets.h>
     11
     12#ifdef CONFIG_PPC64
     13#define SAVE_30GPRS(base) SAVE_GPRS(2, 31, base)
     14#define REST_30GPRS(base) REST_GPRS(2, 31, base)
     15#define TEMPLATE_FOR_IMM_LOAD_INSNS	nop; nop; nop; nop; nop
     16#else
     17#define SAVE_30GPRS(base) stmw	r2, GPR2(base)
     18#define REST_30GPRS(base) lmw	r2, GPR2(base)
     19#define TEMPLATE_FOR_IMM_LOAD_INSNS	nop; nop; nop
     20#endif
     21
     22#define	OPT_SLOT_SIZE	65536
     23
     24	.balign	4
     25
     26	/*
     27	 * Reserve an area to allocate slots for detour buffer.
     28	 * This is part of .text section (rather than vmalloc area)
     29	 * as this needs to be within 32MB of the probed address.
     30	 */
     31	.global optinsn_slot
     32optinsn_slot:
     33	.space	OPT_SLOT_SIZE
     34
     35	/*
     36	 * Optprobe template:
     37	 * This template gets copied into one of the slots in optinsn_slot
     38	 * and gets fixed up with real optprobe structures et al.
     39	 */
     40	.global optprobe_template_entry
     41optprobe_template_entry:
     42	/* Create an in-memory pt_regs */
     43	PPC_STLU	r1,-INT_FRAME_SIZE(r1)
     44	SAVE_GPR(0,r1)
     45	/* Save the previous SP into stack */
     46	addi	r0,r1,INT_FRAME_SIZE
     47	PPC_STL	r0,GPR1(r1)
     48	SAVE_30GPRS(r1)
     49	/* Save SPRS */
     50	mfmsr	r5
     51	PPC_STL	r5,_MSR(r1)
     52	li	r5,0x700
     53	PPC_STL	r5,_TRAP(r1)
     54	li	r5,0
     55	PPC_STL	r5,ORIG_GPR3(r1)
     56	PPC_STL	r5,RESULT(r1)
     57	mfctr	r5
     58	PPC_STL	r5,_CTR(r1)
     59	mflr	r5
     60	PPC_STL	r5,_LINK(r1)
     61	mfspr	r5,SPRN_XER
     62	PPC_STL	r5,_XER(r1)
     63	mfcr	r5
     64	PPC_STL	r5,_CCR(r1)
     65#ifdef CONFIG_PPC64
     66	lbz     r5,PACAIRQSOFTMASK(r13)
     67	std     r5,SOFTE(r1)
     68#endif
     69
     70	/*
     71	 * We may get here from a module, so load the kernel TOC in r2.
     72	 * The original TOC gets restored when pt_regs is restored
     73	 * further below.
     74	 */
     75#ifdef CONFIG_PPC64
     76	ld	r2,PACATOC(r13)
     77#endif
     78
     79	.global optprobe_template_op_address
     80optprobe_template_op_address:
     81	/*
     82	 * Parameters to optimized_callback():
     83	 * 1. optimized_kprobe structure in r3
     84	 */
     85	TEMPLATE_FOR_IMM_LOAD_INSNS
     86
     87	/* 2. pt_regs pointer in r4 */
     88	addi	r4,r1,STACK_FRAME_OVERHEAD
     89
     90	.global optprobe_template_call_handler
     91optprobe_template_call_handler:
     92	/* Branch to optimized_callback() */
     93	nop
     94
     95	/*
     96	 * Parameters for instruction emulation:
     97	 * 1. Pass SP in register r3.
     98	 */
     99	addi	r3,r1,STACK_FRAME_OVERHEAD
    100
    101	.global optprobe_template_insn
    102optprobe_template_insn:
    103	/* 2, Pass instruction to be emulated in r4 */
    104	TEMPLATE_FOR_IMM_LOAD_INSNS
    105
    106	.global optprobe_template_call_emulate
    107optprobe_template_call_emulate:
    108	/* Branch to emulate_step()  */
    109	nop
    110
    111	/*
    112	 * All done.
    113	 * Now, restore the registers...
    114	 */
    115	PPC_LL	r5,_MSR(r1)
    116	mtmsr	r5
    117	PPC_LL	r5,_CTR(r1)
    118	mtctr	r5
    119	PPC_LL	r5,_LINK(r1)
    120	mtlr	r5
    121	PPC_LL	r5,_XER(r1)
    122	mtxer	r5
    123	PPC_LL	r5,_CCR(r1)
    124	mtcr	r5
    125	REST_GPR(0,r1)
    126	REST_30GPRS(r1)
    127	/* Restore the previous SP */
    128	addi	r1,r1,INT_FRAME_SIZE
    129
    130	.global optprobe_template_ret
    131optprobe_template_ret:
    132	/* ... and jump back from trampoline */
    133	nop
    134
    135	.global optprobe_template_end
    136optprobe_template_end: