/*
* Kernel Probes (KProbes)
* arch/ia64/kernel/kprobes.c
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright (C) IBM Corporation, 2002, 2004
* Copyright (C) Intel Corporation, 2005
*
* 2005-Apr Rusty Lynch <rusty.lynch@intel.com> and Anil S Keshavamurthy
* <anil.s.keshavamurthy@intel.com> adapted from i386
*/
#include <linux/config.h>
#include <linux/kprobes.h>
#include <linux/ptrace.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/preempt.h>
#include <linux/moduleloader.h>
#include <asm/pgtable.h>
#include <asm/kdebug.h>
extern void jprobe_inst_return(void);
/* kprobe_status settings */
#define KPROBE_HIT_ACTIVE 0x00000001
#define KPROBE_HIT_SS 0x00000002
static struct kprobe *current_kprobe;
static unsigned long kprobe_status;
static struct pt_regs jprobe_saved_regs;
enum instruction_type {A, I, M, F, B, L, X, u};
static enum instruction_type bundle_encoding[32][3] = {
{ M, I, I }, /* 00 */
{ M, I, I }, /* 01 */
{ M, I, I }, /* 02 */
{ M, I, I }, /* 03 */
{ M, L, X }, /* 04 */
{ M, L, X }, /* 05 */
{ u, u, u }, /* 06 */
{ u, u, u }, /* 07 */
{ M, M, I }, /* 08 */
{ M, M, I }, /* 09 */
{ M, M, I }, /* 0A */
{ M, M, I }, /* 0B */
{ M, F, I }, /* 0C */
{ M, F, I }, /* 0D */
{ M, M, F }, /* 0E */
{ M, M, F }, /* 0F */
{ M, I, B }, /* 10 */
{ M, I, B }, /* 11 */
{ M, B, B }, /* 12 */
{ M, B, B }, /* 13 */
{ u, u, u }, /* 14 */
{ u, u, u }, /* 15 */
{ B, B, B }, /* 16 */
{ B, B, B }, /* 17 */
{ M, M, B }, /* 18 */
{ M, M, B }, /* 19 */
{ u, u, u }, /* 1A */
{ u, u, u }, /* 1B */
{ M, F, B }, /* 1C */
{ M, F, B }, /* 1D */
{ u, u, u }, /* 1E */
{ u, u, u }, /* 1F */
};
int arch_prepare_kprobe(struct kprobe *p)
{
unsigned long addr = (unsigned long) p->addr;
unsigned long bundle_addr = addr & ~0xFULL;
unsigned long slot = addr & 0xf;
bundle_t bundle;
unsigned long template;
/*
* TODO: Verify that a probe is not being inserted
* in sensitive regions of code
* TODO: Verify that the memory holding the probe is rwx
* TODO: verify this is a kernel address
*/
memcpy(&bundle, (unsigned long *)bundle_addr, sizeof(bundle_t));
template = bundle.quad0.template;
if (((bundle_encoding[template][1] == L) && slot > 1) || (slot > 2)) {
printk(KERN_WARNING "Attempting to insert unaligned kprobe at 0x%lx\n", addr);
return -EINVAL;
}
return 0;
}
void arch_copy_kprobe(struct kprobe *p)
{
unsigned long addr = (unsigned long)p->addr;
unsigned long bundle_addr = addr & ~0xFULL;
memcpy(&p->ainsn.insn.bundle, (unsigned long *)bundle_addr,
sizeof(bundle_t));
memcpy(&p->opcode.bundle, &p->ainsn.insn.bundle, sizeof(bundle_t));
}
void arch_arm_kprobe(struct kprobe *p)
{
unsigned long addr = (unsigned long)p->addr;
unsigned long arm_addr = addr & ~0xFULL;
unsigned long slot = addr & 0xf;
unsigned long template;
bundle_t bundle;
memcpy(&bundle, &p->ainsn.insn.bundle, sizeof(bundle_t));
template = bundle.quad0.template;
if (slot == 1 && bundle_encoding[template][1] == L)
slot = 2;
switch (slot) {
case 0:
bundle.quad0.slot0 = BREAK_INST;
break;
case 1:
bundle.quad0.slot1_p0 = BREAK_INST;
bundle.quad1.slot1_p1 = (BREAK_INST >> (64-46));
break;
case 2:
bundle.quad1.slot2 = BREAK_INST;
break;
}
/* Flush icache for the instruction at the emulated address */
flush_icache_range((unsigned long)&p->ainsn.insn.bundle,
(unsigned long)&p->ainsn.insn.bundle +
sizeof(bundle_t));
/*
* Patch the original instruction with the probe instruction
* and flush the instruction cache
*/
memcpy((char *) arm_addr, (char *) &bundle, sizeof(bundle_t));
flush_icache_range(arm_addr, arm_addr + sizeof(bundle_t));
}
void arch_disarm_kprobe(struct kprobe *p)
{
unsigned long addr = (unsigned long)p->addr;
unsigned long arm_addr = addr & ~0xFULL;
/* p->opcode contains the original unaltered bundle */
memcpy((char *) arm_addr, (char *) &p->opcode.bundle, sizeof(bundle_t));
flush_icache_range(arm_addr, arm_addr + sizeof(bundle_t));
}
void arch_remove_kprobe(struct kprobe *p)
{
}
/*
* We are resuming execution after a single step fault, so the pt_regs
* structure reflects the register state after we executed the instruction
* located in the kprobe (p->ainsn.insn.bundle). We still need to adjust
* the ip to point back to the original stack address, and if we see that
* the slot has incremented back to zero, then we need to point to the next
* slot location.
*/
static void resume_execution(struct kprobe *p, struct pt_regs *regs)
{
unsigned long bundle = (unsigned long)p->addr & ~0xFULL;
/*
* TODO: Handle cases where kprobe was inserted on a branch instruction
*/
if (!ia64_psr(regs)->ri)
regs->cr_iip = bundle + 0x10;
else
regs->cr_iip = bundle;
ia64_psr(regs)->ss = 0;
}
static void prepare_ss(struct kprobe *p, struct pt_regs *regs)
{
unsigned long bundle_addr = (unsigned long) &p->ainsn.insn.bundle;
unsigned long slot = (unsigned long)p->addr & 0xf;
/* Update instruction pointer (IIP) and slot number (IPSR.ri) */
regs->cr_iip = bundle_addr & ~0xFULL;
if (slot > 2)
slot = 0;
ia64_psr(regs)->ri = slot;
/* turn on single stepping */
ia64_psr(regs)->ss = 1;
}
static int pre_kprobes_handler(struct pt_regs *regs)
{
struct kprobe *p;
int ret = 0;
kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);
preempt_disable();
/* Handle recursion cases */
if (kprobe_running()) {
p = get_kprobe(addr);
if (p) {
if (kprobe_status == KPROBE_HIT_SS) {
unlock_kprobes();
goto no_kprobe;
}
arch_disarm_kprobe(p);
ret = 1;
} else {
/*
* jprobe instrumented function just completed
*/
p = current_kprobe;
if (p->break_handler && p->break_handler(p, regs)) {
goto ss_probe;
}
}
}
lock_kprobes();
p = get_kprobe(addr);
if (!p) {
unlock_kprobes();
goto no_kprobe;
}
kprobe_status = KPROBE_HIT_ACTIVE;
current_kprobe = p;
if (p->pre_handler && p->pre_handler(p, regs))
/*
* Our pre-handler is specifically requesting that we just
* do a return. This is handling the case where the
* pre-handler is really our special jprobe pre-handler.
*/
return 1;
ss_probe:
prepare_ss(p, regs);
kprobe_status = KPROBE_HIT_SS;
return 1;
no_kprobe:
preempt_enable_no_resched();
return ret;
}
static int post_kprobes_handler(struct pt_regs *regs)
{
if (!kprobe_running())
return 0;
if (current_kprobe->post_handler)
current_kprobe->post_handler(current_kprobe, regs, 0);
resume_execution(current_kprobe, regs);
unlock_kprobes();
preempt_enable_no_resched();
return 1;
}
static int kprobes_fault_handler(struct pt_regs *regs, int trapnr)
{
if (!kprobe_running())
return 0;
if (current_kprobe->fault_handler &&
current_kprobe->fault_handler(current_kprobe, regs, trapnr))
return 1;
if (kprobe_status & KPROBE_HIT_SS) {
resume_execution(current_kprobe, regs);
unlock_kprobes();
preempt_enable_no_resched();
}
return 0;
}
int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val,
void *data)
{
struct die_args *args = (struct die_args *)data;
switch(val) {
case DIE_BREAK:
if (pre_kprobes_handler(args->regs))
return NOTIFY_STOP;
break;
case DIE_SS:
if (post_kprobes_handler(args->regs))
return NOTIFY_STOP;
break;
case DIE_PAGE_FAULT:
if (kprobes_fault_handler(args->regs, args->trapnr))
return NOTIFY_STOP;
default:
break;
}
return NOTIFY_DONE;
}
int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
{
struct jprobe *jp = container_of(p, struct jprobe, kp);
unsigned long addr = ((struct fnptr *)(jp->entry))->ip;
/* save architectural state */
jprobe_saved_regs = *regs;
/* after rfi, execute the jprobe instrumented function */
regs->cr_iip = addr & ~0xFULL;
ia64_psr(regs)->ri = addr & 0xf;
regs->r1 = ((struct fnptr *)(jp->entry))->gp;
/*
* fix the return address to our jprobe_inst_return() function
* in the jprobes.S file
*/
regs->b0 = ((struct fnptr *)(jprobe_inst_return))->ip;
return 1;
}
int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
{
*regs = jprobe_saved_regs;
return 1;
}
