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aea490299f
The str_pc_offset value is architecturally defined on ARMv7 onwards so we can make it a compile time constant. This means on Thumb kernels the runtime checking code isn't needed, which saves us from having to fix it to work for Thumb. Signed-off-by: Jon Medhurst <tixy@yxit.co.uk> Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
143 lines
3.3 KiB
C
143 lines
3.3 KiB
C
/*
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* arch/arm/kernel/kprobes-common.c
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*
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* Copyright (C) 2011 Jon Medhurst <tixy@yxit.co.uk>.
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*
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* Some contents moved here from arch/arm/include/asm/kprobes-arm.c which is
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* Copyright (C) 2006, 2007 Motorola Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/kernel.h>
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#include <linux/kprobes.h>
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#include "kprobes.h"
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#ifndef find_str_pc_offset
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/*
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* For STR and STM instructions, an ARM core may choose to use either
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* a +8 or a +12 displacement from the current instruction's address.
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* Whichever value is chosen for a given core, it must be the same for
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* both instructions and may not change. This function measures it.
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*/
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int str_pc_offset;
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void __init find_str_pc_offset(void)
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{
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int addr, scratch, ret;
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__asm__ (
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"sub %[ret], pc, #4 \n\t"
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"str pc, %[addr] \n\t"
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"ldr %[scr], %[addr] \n\t"
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"sub %[ret], %[scr], %[ret] \n\t"
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: [ret] "=r" (ret), [scr] "=r" (scratch), [addr] "+m" (addr));
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str_pc_offset = ret;
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}
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#endif /* !find_str_pc_offset */
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void __init arm_kprobe_decode_init(void)
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{
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find_str_pc_offset();
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}
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static unsigned long __kprobes __check_eq(unsigned long cpsr)
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{
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return cpsr & PSR_Z_BIT;
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}
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static unsigned long __kprobes __check_ne(unsigned long cpsr)
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{
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return (~cpsr) & PSR_Z_BIT;
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}
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static unsigned long __kprobes __check_cs(unsigned long cpsr)
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{
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return cpsr & PSR_C_BIT;
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}
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static unsigned long __kprobes __check_cc(unsigned long cpsr)
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{
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return (~cpsr) & PSR_C_BIT;
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}
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static unsigned long __kprobes __check_mi(unsigned long cpsr)
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{
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return cpsr & PSR_N_BIT;
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}
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static unsigned long __kprobes __check_pl(unsigned long cpsr)
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{
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return (~cpsr) & PSR_N_BIT;
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}
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static unsigned long __kprobes __check_vs(unsigned long cpsr)
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{
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return cpsr & PSR_V_BIT;
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}
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static unsigned long __kprobes __check_vc(unsigned long cpsr)
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{
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return (~cpsr) & PSR_V_BIT;
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}
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static unsigned long __kprobes __check_hi(unsigned long cpsr)
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{
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cpsr &= ~(cpsr >> 1); /* PSR_C_BIT &= ~PSR_Z_BIT */
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return cpsr & PSR_C_BIT;
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}
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static unsigned long __kprobes __check_ls(unsigned long cpsr)
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{
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cpsr &= ~(cpsr >> 1); /* PSR_C_BIT &= ~PSR_Z_BIT */
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return (~cpsr) & PSR_C_BIT;
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}
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static unsigned long __kprobes __check_ge(unsigned long cpsr)
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{
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cpsr ^= (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */
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return (~cpsr) & PSR_N_BIT;
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}
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static unsigned long __kprobes __check_lt(unsigned long cpsr)
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{
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cpsr ^= (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */
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return cpsr & PSR_N_BIT;
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}
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static unsigned long __kprobes __check_gt(unsigned long cpsr)
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{
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unsigned long temp = cpsr ^ (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */
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temp |= (cpsr << 1); /* PSR_N_BIT |= PSR_Z_BIT */
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return (~temp) & PSR_N_BIT;
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}
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static unsigned long __kprobes __check_le(unsigned long cpsr)
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{
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unsigned long temp = cpsr ^ (cpsr << 3); /* PSR_N_BIT ^= PSR_V_BIT */
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temp |= (cpsr << 1); /* PSR_N_BIT |= PSR_Z_BIT */
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return temp & PSR_N_BIT;
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}
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static unsigned long __kprobes __check_al(unsigned long cpsr)
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{
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return true;
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}
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kprobe_check_cc * const kprobe_condition_checks[16] = {
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&__check_eq, &__check_ne, &__check_cs, &__check_cc,
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&__check_mi, &__check_pl, &__check_vs, &__check_vc,
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&__check_hi, &__check_ls, &__check_ge, &__check_lt,
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&__check_gt, &__check_le, &__check_al, &__check_al
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};
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