ARC: kprobes support
Origin port done by Rajeshwar Ranga Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Cc: Rajeshwar Ranga <rajeshwar.ranga@gmail.com>
This commit is contained in:
Vineet Gupta
parent
e65ab5a875
commit
4d86dfbbda
7 changed files with 610 additions and 3 deletions
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@ -24,6 +24,8 @@ config ARC
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select GENERIC_SMP_IDLE_THREAD
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select HAVE_ARCH_TRACEHOOK
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select HAVE_GENERIC_HARDIRQS
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select HAVE_KPROBES
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select HAVE_KRETPROBES
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select HAVE_MEMBLOCK
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select HAVE_MOD_ARCH_SPECIFIC if ARC_DW2_UNWIND
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select HAVE_OPROFILE
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62
arch/arc/include/asm/kprobes.h
Normal file
62
arch/arc/include/asm/kprobes.h
Normal file
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@ -0,0 +1,62 @@
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/*
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* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
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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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#ifndef _ARC_KPROBES_H
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#define _ARC_KPROBES_H
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#ifdef CONFIG_KPROBES
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typedef u16 kprobe_opcode_t;
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#define UNIMP_S_INSTRUCTION 0x79e0
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#define TRAP_S_2_INSTRUCTION 0x785e
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#define MAX_INSN_SIZE 8
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#define MAX_STACK_SIZE 64
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struct arch_specific_insn {
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int is_short;
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kprobe_opcode_t *t1_addr, *t2_addr;
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kprobe_opcode_t t1_opcode, t2_opcode;
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};
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#define flush_insn_slot(p) do { } while (0)
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#define kretprobe_blacklist_size 0
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struct kprobe;
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void arch_remove_kprobe(struct kprobe *p);
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int kprobe_exceptions_notify(struct notifier_block *self,
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unsigned long val, void *data);
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struct prev_kprobe {
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struct kprobe *kp;
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unsigned long status;
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};
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struct kprobe_ctlblk {
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unsigned int kprobe_status;
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struct pt_regs jprobe_saved_regs;
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char jprobes_stack[MAX_STACK_SIZE];
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struct prev_kprobe prev_kprobe;
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};
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int kprobe_fault_handler(struct pt_regs *regs, unsigned long cause);
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void kretprobe_trampoline(void);
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void trap_is_kprobe(unsigned long cause, unsigned long address,
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struct pt_regs *regs);
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#else
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static void trap_is_kprobe(unsigned long cause, unsigned long address,
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struct pt_regs *regs)
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{
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}
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#endif
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#endif
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@ -111,6 +111,11 @@ struct callee_regs {
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(struct pt_regs *)(pg_start + THREAD_SIZE - 4) - 1; \
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})
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static inline long regs_return_value(struct pt_regs *regs)
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{
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return regs->r0;
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}
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#endif /* !__ASSEMBLY__ */
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#define orig_r8_IS_SCALL 0x0001
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@ -15,6 +15,7 @@ obj-y += devtree.o
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obj-$(CONFIG_MODULES) += arcksyms.o module.o
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obj-$(CONFIG_SMP) += smp.o
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obj-$(CONFIG_ARC_DW2_UNWIND) += unwind.o
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obj-$(CONFIG_KPROBES) += kprobes.o
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obj-$(CONFIG_ARC_FPU_SAVE_RESTORE) += fpu.o
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CFLAGS_fpu.o += -mdpfp
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@ -497,9 +497,8 @@ void __kprobes set_reg(int reg, long val, struct pt_regs *regs,
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* @pc +2/4/6 (ARCompact ISA allows free intermixing of 16/32 bit insns).
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*
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* If @pc is a branch
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* -@tgt_if_br is set to branch target.
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* -If branch has delay slot, @next_pc updated with actual next PC.
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*
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* -@tgt_if_br is set to branch target.
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* -If branch has delay slot, @next_pc updated with actual next PC.
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*/
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int __kprobes disasm_next_pc(unsigned long pc, struct pt_regs *regs,
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struct callee_regs *cregs,
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525
arch/arc/kernel/kprobes.c
Normal file
525
arch/arc/kernel/kprobes.c
Normal file
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@ -0,0 +1,525 @@
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/*
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* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
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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/types.h>
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#include <linux/kprobes.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/kprobes.h>
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#include <linux/kdebug.h>
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#include <linux/sched.h>
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#include <linux/uaccess.h>
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#include <asm/cacheflush.h>
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#include <asm/current.h>
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#include <asm/disasm.h>
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#define MIN_STACK_SIZE(addr) min((unsigned long)MAX_STACK_SIZE, \
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(unsigned long)current_thread_info() + THREAD_SIZE - (addr))
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DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
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DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
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int __kprobes arch_prepare_kprobe(struct kprobe *p)
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{
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/* Attempt to probe at unaligned address */
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if ((unsigned long)p->addr & 0x01)
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return -EINVAL;
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/* Address should not be in exception handling code */
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p->ainsn.is_short = is_short_instr((unsigned long)p->addr);
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p->opcode = *p->addr;
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return 0;
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}
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void __kprobes arch_arm_kprobe(struct kprobe *p)
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{
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*p->addr = UNIMP_S_INSTRUCTION;
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flush_icache_range((unsigned long)p->addr,
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(unsigned long)p->addr + sizeof(kprobe_opcode_t));
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}
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void __kprobes arch_disarm_kprobe(struct kprobe *p)
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{
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*p->addr = p->opcode;
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flush_icache_range((unsigned long)p->addr,
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(unsigned long)p->addr + sizeof(kprobe_opcode_t));
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}
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void __kprobes arch_remove_kprobe(struct kprobe *p)
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{
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arch_disarm_kprobe(p);
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/* Can we remove the kprobe in the middle of kprobe handling? */
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if (p->ainsn.t1_addr) {
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*(p->ainsn.t1_addr) = p->ainsn.t1_opcode;
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flush_icache_range((unsigned long)p->ainsn.t1_addr,
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(unsigned long)p->ainsn.t1_addr +
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sizeof(kprobe_opcode_t));
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p->ainsn.t1_addr = NULL;
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}
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if (p->ainsn.t2_addr) {
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*(p->ainsn.t2_addr) = p->ainsn.t2_opcode;
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flush_icache_range((unsigned long)p->ainsn.t2_addr,
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(unsigned long)p->ainsn.t2_addr +
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sizeof(kprobe_opcode_t));
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p->ainsn.t2_addr = NULL;
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}
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}
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static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
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{
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kcb->prev_kprobe.kp = kprobe_running();
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kcb->prev_kprobe.status = kcb->kprobe_status;
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}
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static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
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{
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__get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
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kcb->kprobe_status = kcb->prev_kprobe.status;
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}
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static inline void __kprobes set_current_kprobe(struct kprobe *p)
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{
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__get_cpu_var(current_kprobe) = p;
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}
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static void __kprobes resume_execution(struct kprobe *p, unsigned long addr,
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struct pt_regs *regs)
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{
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/* Remove the trap instructions inserted for single step and
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* restore the original instructions
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*/
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if (p->ainsn.t1_addr) {
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*(p->ainsn.t1_addr) = p->ainsn.t1_opcode;
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flush_icache_range((unsigned long)p->ainsn.t1_addr,
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(unsigned long)p->ainsn.t1_addr +
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sizeof(kprobe_opcode_t));
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p->ainsn.t1_addr = NULL;
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}
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if (p->ainsn.t2_addr) {
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*(p->ainsn.t2_addr) = p->ainsn.t2_opcode;
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flush_icache_range((unsigned long)p->ainsn.t2_addr,
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(unsigned long)p->ainsn.t2_addr +
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sizeof(kprobe_opcode_t));
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p->ainsn.t2_addr = NULL;
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}
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return;
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}
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static void __kprobes setup_singlestep(struct kprobe *p, struct pt_regs *regs)
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{
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unsigned long next_pc;
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unsigned long tgt_if_br = 0;
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int is_branch;
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unsigned long bta;
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/* Copy the opcode back to the kprobe location and execute the
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* instruction. Because of this we will not be able to get into the
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* same kprobe until this kprobe is done
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*/
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*(p->addr) = p->opcode;
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flush_icache_range((unsigned long)p->addr,
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(unsigned long)p->addr + sizeof(kprobe_opcode_t));
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/* Now we insert the trap at the next location after this instruction to
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* single step. If it is a branch we insert the trap at possible branch
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* targets
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*/
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bta = regs->bta;
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if (regs->status32 & 0x40) {
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/* We are in a delay slot with the branch taken */
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next_pc = bta & ~0x01;
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if (!p->ainsn.is_short) {
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if (bta & 0x01)
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regs->blink += 2;
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else {
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/* Branch not taken */
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next_pc += 2;
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/* next pc is taken from bta after executing the
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* delay slot instruction
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*/
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regs->bta += 2;
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}
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}
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is_branch = 0;
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} else
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is_branch =
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disasm_next_pc((unsigned long)p->addr, regs,
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(struct callee_regs *) current->thread.callee_reg,
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&next_pc, &tgt_if_br);
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p->ainsn.t1_addr = (kprobe_opcode_t *) next_pc;
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p->ainsn.t1_opcode = *(p->ainsn.t1_addr);
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*(p->ainsn.t1_addr) = TRAP_S_2_INSTRUCTION;
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flush_icache_range((unsigned long)p->ainsn.t1_addr,
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(unsigned long)p->ainsn.t1_addr +
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sizeof(kprobe_opcode_t));
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if (is_branch) {
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p->ainsn.t2_addr = (kprobe_opcode_t *) tgt_if_br;
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p->ainsn.t2_opcode = *(p->ainsn.t2_addr);
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*(p->ainsn.t2_addr) = TRAP_S_2_INSTRUCTION;
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flush_icache_range((unsigned long)p->ainsn.t2_addr,
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(unsigned long)p->ainsn.t2_addr +
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sizeof(kprobe_opcode_t));
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}
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}
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int __kprobes arc_kprobe_handler(unsigned long addr, struct pt_regs *regs)
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{
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struct kprobe *p;
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struct kprobe_ctlblk *kcb;
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preempt_disable();
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kcb = get_kprobe_ctlblk();
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p = get_kprobe((unsigned long *)addr);
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if (p) {
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/*
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* We have reentered the kprobe_handler, since another kprobe
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* was hit while within the handler, we save the original
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* kprobes and single step on the instruction of the new probe
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* without calling any user handlers to avoid recursive
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* kprobes.
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*/
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if (kprobe_running()) {
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save_previous_kprobe(kcb);
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set_current_kprobe(p);
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kprobes_inc_nmissed_count(p);
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setup_singlestep(p, regs);
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kcb->kprobe_status = KPROBE_REENTER;
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return 1;
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}
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set_current_kprobe(p);
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kcb->kprobe_status = KPROBE_HIT_ACTIVE;
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/* If we have no pre-handler or it returned 0, we continue with
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* normal processing. If we have a pre-handler and it returned
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* non-zero - which is expected from setjmp_pre_handler for
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* jprobe, we return without single stepping and leave that to
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* the break-handler which is invoked by a kprobe from
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* jprobe_return
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*/
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if (!p->pre_handler || !p->pre_handler(p, regs)) {
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setup_singlestep(p, regs);
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kcb->kprobe_status = KPROBE_HIT_SS;
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}
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return 1;
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} else if (kprobe_running()) {
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p = __get_cpu_var(current_kprobe);
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if (p->break_handler && p->break_handler(p, regs)) {
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setup_singlestep(p, regs);
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kcb->kprobe_status = KPROBE_HIT_SS;
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return 1;
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}
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}
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/* no_kprobe: */
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preempt_enable_no_resched();
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return 0;
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}
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static int __kprobes arc_post_kprobe_handler(unsigned long addr,
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struct pt_regs *regs)
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{
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struct kprobe *cur = kprobe_running();
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struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
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if (!cur)
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return 0;
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resume_execution(cur, addr, regs);
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/* Rearm the kprobe */
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arch_arm_kprobe(cur);
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/*
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* When we return from trap instruction we go to the next instruction
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* We restored the actual instruction in resume_exectuiont and we to
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* return to the same address and execute it
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*/
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regs->ret = addr;
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if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
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kcb->kprobe_status = KPROBE_HIT_SSDONE;
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cur->post_handler(cur, regs, 0);
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}
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if (kcb->kprobe_status == KPROBE_REENTER) {
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restore_previous_kprobe(kcb);
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goto out;
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}
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reset_current_kprobe();
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out:
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preempt_enable_no_resched();
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return 1;
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}
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/*
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* Fault can be for the instruction being single stepped or for the
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* pre/post handlers in the module.
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* This is applicable for applications like user probes, where we have the
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* probe in user space and the handlers in the kernel
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*/
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int __kprobes kprobe_fault_handler(struct pt_regs *regs, unsigned long trapnr)
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{
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struct kprobe *cur = kprobe_running();
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struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
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switch (kcb->kprobe_status) {
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case KPROBE_HIT_SS:
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case KPROBE_REENTER:
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/*
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* We are here because the instruction being single stepped
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* caused the fault. We reset the current kprobe and allow the
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* exception handler as if it is regular exception. In our
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* case it doesn't matter because the system will be halted
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*/
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resume_execution(cur, (unsigned long)cur->addr, regs);
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if (kcb->kprobe_status == KPROBE_REENTER)
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restore_previous_kprobe(kcb);
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else
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reset_current_kprobe();
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preempt_enable_no_resched();
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break;
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case KPROBE_HIT_ACTIVE:
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case KPROBE_HIT_SSDONE:
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/*
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* We are here because the instructions in the pre/post handler
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* caused the fault.
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*/
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/* We increment the nmissed count for accounting,
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* we can also use npre/npostfault count for accouting
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* these specific fault cases.
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*/
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kprobes_inc_nmissed_count(cur);
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/*
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* We come here because instructions in the pre/post
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* handler caused the page_fault, this could happen
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* if handler tries to access user space by
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* copy_from_user(), get_user() etc. Let the
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* user-specified handler try to fix it first.
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*/
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if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
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return 1;
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/*
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* In case the user-specified fault handler returned zero,
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* try to fix up.
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*/
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if (fixup_exception(regs))
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return 1;
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/*
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* fixup_exception() could not handle it,
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* Let do_page_fault() fix it.
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*/
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break;
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default:
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break;
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}
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return 0;
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}
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int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
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unsigned long val, void *data)
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{
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struct die_args *args = data;
|
||||
unsigned long addr = args->err;
|
||||
int ret = NOTIFY_DONE;
|
||||
|
||||
switch (val) {
|
||||
case DIE_IERR:
|
||||
if (arc_kprobe_handler(addr, args->regs))
|
||||
return NOTIFY_STOP;
|
||||
break;
|
||||
|
||||
case DIE_TRAP:
|
||||
if (arc_post_kprobe_handler(addr, args->regs))
|
||||
return NOTIFY_STOP;
|
||||
break;
|
||||
|
||||
default:
|
||||
break;
|
||||
}
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
|
||||
{
|
||||
struct jprobe *jp = container_of(p, struct jprobe, kp);
|
||||
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
|
||||
unsigned long sp_addr = regs->sp;
|
||||
|
||||
kcb->jprobe_saved_regs = *regs;
|
||||
memcpy(kcb->jprobes_stack, (void *)sp_addr, MIN_STACK_SIZE(sp_addr));
|
||||
regs->ret = (unsigned long)(jp->entry);
|
||||
|
||||
return 1;
|
||||
}
|
||||
|
||||
void __kprobes jprobe_return(void)
|
||||
{
|
||||
__asm__ __volatile__("unimp_s");
|
||||
return;
|
||||
}
|
||||
|
||||
int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
|
||||
{
|
||||
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
|
||||
unsigned long sp_addr;
|
||||
|
||||
*regs = kcb->jprobe_saved_regs;
|
||||
sp_addr = regs->sp;
|
||||
memcpy((void *)sp_addr, kcb->jprobes_stack, MIN_STACK_SIZE(sp_addr));
|
||||
preempt_enable_no_resched();
|
||||
|
||||
return 1;
|
||||
}
|
||||
|
||||
static void __used kretprobe_trampoline_holder(void)
|
||||
{
|
||||
__asm__ __volatile__(".global kretprobe_trampoline\n"
|
||||
"kretprobe_trampoline:\n" "nop\n");
|
||||
}
|
||||
|
||||
void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
|
||||
struct pt_regs *regs)
|
||||
{
|
||||
|
||||
ri->ret_addr = (kprobe_opcode_t *) regs->blink;
|
||||
|
||||
/* Replace the return addr with trampoline addr */
|
||||
regs->blink = (unsigned long)&kretprobe_trampoline;
|
||||
}
|
||||
|
||||
static int __kprobes trampoline_probe_handler(struct kprobe *p,
|
||||
struct pt_regs *regs)
|
||||
{
|
||||
struct kretprobe_instance *ri = NULL;
|
||||
struct hlist_head *head, empty_rp;
|
||||
struct hlist_node *node, *tmp;
|
||||
unsigned long flags, orig_ret_address = 0;
|
||||
unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline;
|
||||
|
||||
INIT_HLIST_HEAD(&empty_rp);
|
||||
kretprobe_hash_lock(current, &head, &flags);
|
||||
|
||||
/*
|
||||
* It is possible to have multiple instances associated with a given
|
||||
* task either because an multiple functions in the call path
|
||||
* have a return probe installed on them, and/or more than one return
|
||||
* return probe was registered for a target function.
|
||||
*
|
||||
* We can handle this because:
|
||||
* - instances are always inserted at the head of the list
|
||||
* - when multiple return probes are registered for the same
|
||||
* function, the first instance's ret_addr will point to the
|
||||
* real return address, and all the rest will point to
|
||||
* kretprobe_trampoline
|
||||
*/
|
||||
hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
|
||||
if (ri->task != current)
|
||||
/* another task is sharing our hash bucket */
|
||||
continue;
|
||||
|
||||
if (ri->rp && ri->rp->handler)
|
||||
ri->rp->handler(ri, regs);
|
||||
|
||||
orig_ret_address = (unsigned long)ri->ret_addr;
|
||||
recycle_rp_inst(ri, &empty_rp);
|
||||
|
||||
if (orig_ret_address != trampoline_address) {
|
||||
/*
|
||||
* This is the real return address. Any other
|
||||
* instances associated with this task are for
|
||||
* other calls deeper on the call stack
|
||||
*/
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
kretprobe_assert(ri, orig_ret_address, trampoline_address);
|
||||
regs->ret = orig_ret_address;
|
||||
|
||||
reset_current_kprobe();
|
||||
kretprobe_hash_unlock(current, &flags);
|
||||
preempt_enable_no_resched();
|
||||
|
||||
hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
|
||||
hlist_del(&ri->hlist);
|
||||
kfree(ri);
|
||||
}
|
||||
|
||||
/* By returning a non zero value, we are telling the kprobe handler
|
||||
* that we don't want the post_handler to run
|
||||
*/
|
||||
return 1;
|
||||
}
|
||||
|
||||
static struct kprobe trampoline_p = {
|
||||
.addr = (kprobe_opcode_t *) &kretprobe_trampoline,
|
||||
.pre_handler = trampoline_probe_handler
|
||||
};
|
||||
|
||||
int __init arch_init_kprobes(void)
|
||||
{
|
||||
/* Registering the trampoline code for the kret probe */
|
||||
return register_kprobe(&trampoline_p);
|
||||
}
|
||||
|
||||
int __kprobes arch_trampoline_kprobe(struct kprobe *p)
|
||||
{
|
||||
if (p->addr == (kprobe_opcode_t *) &kretprobe_trampoline)
|
||||
return 1;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
void trap_is_kprobe(unsigned long cause, unsigned long address,
|
||||
struct pt_regs *regs)
|
||||
{
|
||||
notify_die(DIE_TRAP, "kprobe_trap", regs, address, cause, SIGTRAP);
|
||||
}
|
||||
|
|
@ -15,6 +15,7 @@
|
|||
#include <linux/uaccess.h>
|
||||
#include <asm/ptrace.h>
|
||||
#include <asm/setup.h>
|
||||
#include <asm/kprobes.h>
|
||||
|
||||
void __init trap_init(void)
|
||||
{
|
||||
|
|
@ -90,6 +91,7 @@ void do_machine_check_fault(unsigned long cause, unsigned long address,
|
|||
die("Machine Check Exception", regs, address, cause);
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* Entry point for traps induced by ARCompact TRAP_S <n> insn
|
||||
* This is same family as TRAP0/SWI insn (use the same vector).
|
||||
|
|
@ -109,6 +111,10 @@ void do_non_swi_trap(unsigned long cause, unsigned long address,
|
|||
trap_is_brkpt(cause, address, regs);
|
||||
break;
|
||||
|
||||
case 2:
|
||||
trap_is_kprobe(param, address, regs);
|
||||
break;
|
||||
|
||||
default:
|
||||
break;
|
||||
}
|
||||
|
|
@ -116,10 +122,17 @@ void do_non_swi_trap(unsigned long cause, unsigned long address,
|
|||
|
||||
/*
|
||||
* Entry point for Instruction Error Exception
|
||||
* -For a corner case, ARC kprobes implementation resorts to using
|
||||
* this exception, hence the check
|
||||
*/
|
||||
void do_insterror_or_kprobe(unsigned long cause,
|
||||
unsigned long address,
|
||||
struct pt_regs *regs)
|
||||
{
|
||||
/* Check if this exception is caused by kprobes */
|
||||
if (notify_die(DIE_IERR, "kprobe_ierr", regs, address,
|
||||
cause, SIGILL) == NOTIFY_STOP)
|
||||
return;
|
||||
|
||||
insterror_is_error(cause, address, regs);
|
||||
}
|
||||
|
|
|
|||
Loading…
Add table
Reference in a new issue