2014-03-07 16:23:04 +00:00
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/*
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* Copyright (C) 2012 Rabin Vincent <rabin at rab.in>
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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/stddef.h>
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#include <linux/errno.h>
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#include <linux/highmem.h>
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#include <linux/sched.h>
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#include <linux/uprobes.h>
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#include <linux/notifier.h>
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#include <asm/opcodes.h>
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#include <asm/traps.h>
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#include "probes.h"
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#include "probes-arm.h"
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#include "uprobes.h"
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#define UPROBE_TRAP_NR UINT_MAX
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bool is_swbp_insn(uprobe_opcode_t *insn)
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{
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return (__mem_to_opcode_arm(*insn) & 0x0fffffff) ==
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(UPROBE_SWBP_ARM_INSN & 0x0fffffff);
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}
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int set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm,
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unsigned long vaddr)
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{
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return uprobe_write_opcode(mm, vaddr,
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__opcode_to_mem_arm(auprobe->bpinsn));
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}
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bool arch_uprobe_ignore(struct arch_uprobe *auprobe, struct pt_regs *regs)
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{
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if (!auprobe->asi.insn_check_cc(regs->ARM_cpsr)) {
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regs->ARM_pc += 4;
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return true;
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}
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return false;
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}
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bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
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{
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probes_opcode_t opcode;
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if (!auprobe->simulate)
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return false;
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opcode = __mem_to_opcode_arm(*(unsigned int *) auprobe->insn);
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auprobe->asi.insn_singlestep(opcode, &auprobe->asi, regs);
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return true;
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}
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unsigned long
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arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr,
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struct pt_regs *regs)
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{
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unsigned long orig_ret_vaddr;
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orig_ret_vaddr = regs->ARM_lr;
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/* Replace the return addr with trampoline addr */
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regs->ARM_lr = trampoline_vaddr;
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return orig_ret_vaddr;
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}
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int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
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unsigned long addr)
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{
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unsigned int insn;
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unsigned int bpinsn;
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enum probes_insn ret;
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/* Thumb not yet support */
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if (addr & 0x3)
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return -EINVAL;
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insn = __mem_to_opcode_arm(*(unsigned int *)auprobe->insn);
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auprobe->ixol[0] = __opcode_to_mem_arm(insn);
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auprobe->ixol[1] = __opcode_to_mem_arm(UPROBE_SS_ARM_INSN);
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ret = arm_probes_decode_insn(insn, &auprobe->asi, false,
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uprobes_probes_actions);
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switch (ret) {
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case INSN_REJECTED:
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return -EINVAL;
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case INSN_GOOD_NO_SLOT:
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auprobe->simulate = true;
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break;
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case INSN_GOOD:
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default:
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break;
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}
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bpinsn = UPROBE_SWBP_ARM_INSN & 0x0fffffff;
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if (insn >= 0xe0000000)
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bpinsn |= 0xe0000000; /* Unconditional instruction */
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else
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bpinsn |= insn & 0xf0000000; /* Copy condition from insn */
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auprobe->bpinsn = bpinsn;
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return 0;
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}
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2014-04-29 03:20:52 +00:00
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void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,
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void *src, unsigned long len)
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{
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void *xol_page_kaddr = kmap_atomic(page);
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void *dst = xol_page_kaddr + (vaddr & ~PAGE_MASK);
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preempt_disable();
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/* Initialize the slot */
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memcpy(dst, src, len);
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/* flush caches (dcache/icache) */
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flush_uprobe_xol_access(page, vaddr, dst, len);
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preempt_enable();
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kunmap_atomic(xol_page_kaddr);
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}
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2014-03-07 16:23:04 +00:00
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int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
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{
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struct uprobe_task *utask = current->utask;
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if (auprobe->prehandler)
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auprobe->prehandler(auprobe, &utask->autask, regs);
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utask->autask.saved_trap_no = current->thread.trap_no;
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current->thread.trap_no = UPROBE_TRAP_NR;
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regs->ARM_pc = utask->xol_vaddr;
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return 0;
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}
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int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
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{
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struct uprobe_task *utask = current->utask;
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WARN_ON_ONCE(current->thread.trap_no != UPROBE_TRAP_NR);
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current->thread.trap_no = utask->autask.saved_trap_no;
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regs->ARM_pc = utask->vaddr + 4;
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if (auprobe->posthandler)
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auprobe->posthandler(auprobe, &utask->autask, regs);
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return 0;
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}
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bool arch_uprobe_xol_was_trapped(struct task_struct *t)
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{
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if (t->thread.trap_no != UPROBE_TRAP_NR)
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return true;
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return false;
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}
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void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
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{
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struct uprobe_task *utask = current->utask;
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current->thread.trap_no = utask->autask.saved_trap_no;
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instruction_pointer_set(regs, utask->vaddr);
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}
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int arch_uprobe_exception_notify(struct notifier_block *self,
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unsigned long val, void *data)
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{
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return NOTIFY_DONE;
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}
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static int uprobe_trap_handler(struct pt_regs *regs, unsigned int instr)
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{
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unsigned long flags;
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local_irq_save(flags);
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instr &= 0x0fffffff;
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if (instr == (UPROBE_SWBP_ARM_INSN & 0x0fffffff))
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uprobe_pre_sstep_notifier(regs);
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else if (instr == (UPROBE_SS_ARM_INSN & 0x0fffffff))
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uprobe_post_sstep_notifier(regs);
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local_irq_restore(flags);
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return 0;
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}
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unsigned long uprobe_get_swbp_addr(struct pt_regs *regs)
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{
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return instruction_pointer(regs);
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}
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static struct undef_hook uprobes_arm_break_hook = {
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.instr_mask = 0x0fffffff,
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.instr_val = (UPROBE_SWBP_ARM_INSN & 0x0fffffff),
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.cpsr_mask = MODE_MASK,
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.cpsr_val = USR_MODE,
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.fn = uprobe_trap_handler,
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};
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static struct undef_hook uprobes_arm_ss_hook = {
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.instr_mask = 0x0fffffff,
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.instr_val = (UPROBE_SS_ARM_INSN & 0x0fffffff),
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.cpsr_mask = MODE_MASK,
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.cpsr_val = USR_MODE,
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.fn = uprobe_trap_handler,
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};
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static int arch_uprobes_init(void)
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{
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register_undef_hook(&uprobes_arm_break_hook);
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register_undef_hook(&uprobes_arm_ss_hook);
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return 0;
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}
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device_initcall(arch_uprobes_init);
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