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linux/arch/ia64/kernel/kprobes.c
Zhang Yanmin d3ef1f5aaf [IA64] prevent accidental modification of args in jprobe handler 
When jprobe is hit, the function parameters of the original function
should be saved before jprobe handler is executed, and restored it after
jprobe handler is executed, because jprobe handler might change the
register values due to tail call optimization by the gcc.

Signed-off-by: Zhang Yanmin <yanmin.zhang@intel.com>
Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2006-01-13 14:45:21 -08:00

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/*
* 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/string.h>
#include <linux/slab.h>
#include <linux/preempt.h>
#include <linux/moduleloader.h>
#include <asm/pgtable.h>
#include <asm/kdebug.h>
#include <asm/sections.h>
extern void jprobe_inst_return(void);
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
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 */
};
/*
* In this function we check to see if the instruction
* is IP relative instruction and update the kprobe
* inst flag accordingly
*/
static void __kprobes update_kprobe_inst_flag(uint template, uint slot,
uint major_opcode,
unsigned long kprobe_inst,
struct kprobe *p)
{
p->ainsn.inst_flag = 0;
p->ainsn.target_br_reg = 0;
/* Check for Break instruction
* Bits 37:40 Major opcode to be zero
* Bits 27:32 X6 to be zero
* Bits 32:35 X3 to be zero
*/
if ((!major_opcode) && (!((kprobe_inst >> 27) & 0x1FF)) ) {
/* is a break instruction */
p->ainsn.inst_flag |= INST_FLAG_BREAK_INST;
return;
}
if (bundle_encoding[template][slot] == B) {
switch (major_opcode) {
case INDIRECT_CALL_OPCODE:
p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
break;
case IP_RELATIVE_PREDICT_OPCODE:
case IP_RELATIVE_BRANCH_OPCODE:
p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
break;
case IP_RELATIVE_CALL_OPCODE:
p->ainsn.inst_flag |= INST_FLAG_FIX_RELATIVE_IP_ADDR;
p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
break;
}
} else if (bundle_encoding[template][slot] == X) {
switch (major_opcode) {
case LONG_CALL_OPCODE:
p->ainsn.inst_flag |= INST_FLAG_FIX_BRANCH_REG;
p->ainsn.target_br_reg = ((kprobe_inst >> 6) & 0x7);
break;
}
}
return;
}
/*
* In this function we check to see if the instruction
* on which we are inserting kprobe is supported.
* Returns 0 if supported
* Returns -EINVAL if unsupported
*/
static int __kprobes unsupported_inst(uint template, uint slot,
uint major_opcode,
unsigned long kprobe_inst,
struct kprobe *p)
{
unsigned long addr = (unsigned long)p->addr;
if (bundle_encoding[template][slot] == I) {
switch (major_opcode) {
case 0x0: //I_UNIT_MISC_OPCODE:
/*
* Check for Integer speculation instruction
* - Bit 33-35 to be equal to 0x1
*/
if (((kprobe_inst >> 33) & 0x7) == 1) {
printk(KERN_WARNING
"Kprobes on speculation inst at <0x%lx> not supported\n",
addr);
return -EINVAL;
}
/*
* IP relative mov instruction
* - Bit 27-35 to be equal to 0x30
*/
if (((kprobe_inst >> 27) & 0x1FF) == 0x30) {
printk(KERN_WARNING
"Kprobes on \"mov r1=ip\" at <0x%lx> not supported\n",
addr);
return -EINVAL;
}
}
}
return 0;
}
/*
* In this function we check to see if the instruction
* (qp) cmpx.crel.ctype p1,p2=r2,r3
* on which we are inserting kprobe is cmp instruction
* with ctype as unc.
*/
static uint __kprobes is_cmp_ctype_unc_inst(uint template, uint slot,
uint major_opcode,
unsigned long kprobe_inst)
{
cmp_inst_t cmp_inst;
uint ctype_unc = 0;
if (!((bundle_encoding[template][slot] == I) ||
(bundle_encoding[template][slot] == M)))
goto out;
if (!((major_opcode == 0xC) || (major_opcode == 0xD) ||
(major_opcode == 0xE)))
goto out;
cmp_inst.l = kprobe_inst;
if ((cmp_inst.f.x2 == 0) || (cmp_inst.f.x2 == 1)) {
/* Integere compare - Register Register (A6 type)*/
if ((cmp_inst.f.tb == 0) && (cmp_inst.f.ta == 0)
&&(cmp_inst.f.c == 1))
ctype_unc = 1;
} else if ((cmp_inst.f.x2 == 2)||(cmp_inst.f.x2 == 3)) {
/* Integere compare - Immediate Register (A8 type)*/
if ((cmp_inst.f.ta == 0) &&(cmp_inst.f.c == 1))
ctype_unc = 1;
}
out:
return ctype_unc;
}
/*
* In this function we override the bundle with
* the break instruction at the given slot.
*/
static void __kprobes prepare_break_inst(uint template, uint slot,
uint major_opcode,
unsigned long kprobe_inst,
struct kprobe *p)
{
unsigned long break_inst = BREAK_INST;
bundle_t *bundle = &p->ainsn.insn.bundle;
/*
* Copy the original kprobe_inst qualifying predicate(qp)
* to the break instruction iff !is_cmp_ctype_unc_inst
* because for cmp instruction with ctype equal to unc,
* which is a special instruction always needs to be
* executed regradless of qp
*/
if (!is_cmp_ctype_unc_inst(template, slot, major_opcode, kprobe_inst))
break_inst |= (0x3f & kprobe_inst);
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;
}
/*
* Update the instruction flag, so that we can
* emulate the instruction properly after we
* single step on original instruction
*/
update_kprobe_inst_flag(template, slot, major_opcode, kprobe_inst, p);
}
static inline void get_kprobe_inst(bundle_t *bundle, uint slot,
unsigned long *kprobe_inst, uint *major_opcode)
{
unsigned long kprobe_inst_p0, kprobe_inst_p1;
unsigned int template;
template = bundle->quad0.template;
switch (slot) {
case 0:
*major_opcode = (bundle->quad0.slot0 >> SLOT0_OPCODE_SHIFT);
*kprobe_inst = bundle->quad0.slot0;
break;
case 1:
*major_opcode = (bundle->quad1.slot1_p1 >> SLOT1_p1_OPCODE_SHIFT);
kprobe_inst_p0 = bundle->quad0.slot1_p0;
kprobe_inst_p1 = bundle->quad1.slot1_p1;
*kprobe_inst = kprobe_inst_p0 | (kprobe_inst_p1 << (64-46));
break;
case 2:
*major_opcode = (bundle->quad1.slot2 >> SLOT2_OPCODE_SHIFT);
*kprobe_inst = bundle->quad1.slot2;
break;
}
}
/* Returns non-zero if the addr is in the Interrupt Vector Table */
static inline int in_ivt_functions(unsigned long addr)
{
return (addr >= (unsigned long)__start_ivt_text
&& addr < (unsigned long)__end_ivt_text);
}
static int __kprobes valid_kprobe_addr(int template, int slot,
unsigned long addr)
{
if ((slot > 2) || ((bundle_encoding[template][1] == L) && slot > 1)) {
printk(KERN_WARNING "Attempting to insert unaligned kprobe "
"at 0x%lx\n", addr);
return -EINVAL;
}
if (in_ivt_functions(addr)) {
printk(KERN_WARNING "Kprobes can't be inserted inside "
"IVT functions at 0x%lx\n", addr);
return -EINVAL;
}
if (slot == 1 && bundle_encoding[template][1] != L) {
printk(KERN_WARNING "Inserting kprobes on slot #1 "
"is not supported\n");
return -EINVAL;
}
return 0;
}
static inline void save_previous_kprobe(struct kprobe_ctlblk *kcb)
{
kcb->prev_kprobe.kp = kprobe_running();
kcb->prev_kprobe.status = kcb->kprobe_status;
}
static inline void restore_previous_kprobe(struct kprobe_ctlblk *kcb)
{
__get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
kcb->kprobe_status = kcb->prev_kprobe.status;
}
static inline void set_current_kprobe(struct kprobe *p,
struct kprobe_ctlblk *kcb)
{
__get_cpu_var(current_kprobe) = p;
}
static void kretprobe_trampoline(void)
{
}
/*
* At this point the target function has been tricked into
* returning into our trampoline. Lookup the associated instance
* and then:
* - call the handler function
* - cleanup by marking the instance as unused
* - long jump back to the original return address
*/
int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
{
struct kretprobe_instance *ri = NULL;
struct hlist_head *head;
struct hlist_node *node, *tmp;
unsigned long flags, orig_ret_address = 0;
unsigned long trampoline_address =
((struct fnptr *)kretprobe_trampoline)->ip;
spin_lock_irqsave(&kretprobe_lock, flags);
head = kretprobe_inst_table_head(current);
/*
* 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 then 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);
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;
}
BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address));
regs->cr_iip = orig_ret_address;
reset_current_kprobe();
spin_unlock_irqrestore(&kretprobe_lock, flags);
preempt_enable_no_resched();
/*
* By returning a non-zero value, we are telling
* kprobe_handler() that we don't want the post_handler
* to run (and have re-enabled preemption)
*/
return 1;
}
/* Called with kretprobe_lock held */
void __kprobes arch_prepare_kretprobe(struct kretprobe *rp,
struct pt_regs *regs)
{
struct kretprobe_instance *ri;
if ((ri = get_free_rp_inst(rp)) != NULL) {
ri->rp = rp;
ri->task = current;
ri->ret_addr = (kprobe_opcode_t *)regs->b0;
/* Replace the return addr with trampoline addr */
regs->b0 = ((struct fnptr *)kretprobe_trampoline)->ip;
add_rp_inst(ri);
} else {
rp->nmissed++;
}
}
int __kprobes arch_prepare_kprobe(struct kprobe *p)
{
unsigned long addr = (unsigned long) p->addr;
unsigned long *kprobe_addr = (unsigned long *)(addr & ~0xFULL);
unsigned long kprobe_inst=0;
unsigned int slot = addr & 0xf, template, major_opcode = 0;
bundle_t *bundle = &p->ainsn.insn.bundle;
memcpy(&p->opcode.bundle, kprobe_addr, sizeof(bundle_t));
memcpy(&p->ainsn.insn.bundle, kprobe_addr, sizeof(bundle_t));
template = bundle->quad0.template;
if(valid_kprobe_addr(template, slot, addr))
return -EINVAL;
/* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
if (slot == 1 && bundle_encoding[template][1] == L)
slot++;
/* Get kprobe_inst and major_opcode from the bundle */
get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
if (unsupported_inst(template, slot, major_opcode, kprobe_inst, p))
return -EINVAL;
prepare_break_inst(template, slot, major_opcode, kprobe_inst, p);
return 0;
}
void __kprobes arch_arm_kprobe(struct kprobe *p)
{
unsigned long addr = (unsigned long)p->addr;
unsigned long arm_addr = addr & ~0xFULL;
memcpy((char *)arm_addr, &p->ainsn.insn.bundle, sizeof(bundle_t));
flush_icache_range(arm_addr, arm_addr + sizeof(bundle_t));
}
void __kprobes 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));
}
/*
* 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. To set the IP address
* to original stack address, handle the case where we need to fixup the
* relative IP address and/or fixup branch register.
*/
static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
{
unsigned long bundle_addr = ((unsigned long) (&p->opcode.bundle)) & ~0xFULL;
unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL;
unsigned long template;
int slot = ((unsigned long)p->addr & 0xf);
template = p->opcode.bundle.quad0.template;
if (slot == 1 && bundle_encoding[template][1] == L)
slot = 2;
if (p->ainsn.inst_flag) {
if (p->ainsn.inst_flag & INST_FLAG_FIX_RELATIVE_IP_ADDR) {
/* Fix relative IP address */
regs->cr_iip = (regs->cr_iip - bundle_addr) + resume_addr;
}
if (p->ainsn.inst_flag & INST_FLAG_FIX_BRANCH_REG) {
/*
* Fix target branch register, software convention is
* to use either b0 or b6 or b7, so just checking
* only those registers
*/
switch (p->ainsn.target_br_reg) {
case 0:
if ((regs->b0 == bundle_addr) ||
(regs->b0 == bundle_addr + 0x10)) {
regs->b0 = (regs->b0 - bundle_addr) +
resume_addr;
}
break;
case 6:
if ((regs->b6 == bundle_addr) ||
(regs->b6 == bundle_addr + 0x10)) {
regs->b6 = (regs->b6 - bundle_addr) +
resume_addr;
}
break;
case 7:
if ((regs->b7 == bundle_addr) ||
(regs->b7 == bundle_addr + 0x10)) {
regs->b7 = (regs->b7 - bundle_addr) +
resume_addr;
}
break;
} /* end switch */
}
goto turn_ss_off;
}
if (slot == 2) {
if (regs->cr_iip == bundle_addr + 0x10) {
regs->cr_iip = resume_addr + 0x10;
}
} else {
if (regs->cr_iip == bundle_addr) {
regs->cr_iip = resume_addr;
}
}
turn_ss_off:
/* Turn off Single Step bit */
ia64_psr(regs)->ss = 0;
}
static void __kprobes prepare_ss(struct kprobe *p, struct pt_regs *regs)
{
unsigned long bundle_addr = (unsigned long) &p->opcode.bundle;
unsigned long slot = (unsigned long)p->addr & 0xf;
/* single step inline if break instruction */
if (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)
regs->cr_iip = (unsigned long)p->addr & ~0xFULL;
else
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 __kprobes is_ia64_break_inst(struct pt_regs *regs)
{
unsigned int slot = ia64_psr(regs)->ri;
unsigned int template, major_opcode;
unsigned long kprobe_inst;
unsigned long *kprobe_addr = (unsigned long *)regs->cr_iip;
bundle_t bundle;
memcpy(&bundle, kprobe_addr, sizeof(bundle_t));
template = bundle.quad0.template;
/* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
if (slot == 1 && bundle_encoding[template][1] == L)
slot++;
/* Get Kprobe probe instruction at given slot*/
get_kprobe_inst(&bundle, slot, &kprobe_inst, &major_opcode);
/* For break instruction,
* Bits 37:40 Major opcode to be zero
* Bits 27:32 X6 to be zero
* Bits 32:35 X3 to be zero
*/
if (major_opcode || ((kprobe_inst >> 27) & 0x1FF) ) {
/* Not a break instruction */
return 0;
}
/* Is a break instruction */
return 1;
}
static int __kprobes pre_kprobes_handler(struct die_args *args)
{
struct kprobe *p;
int ret = 0;
struct pt_regs *regs = args->regs;
kprobe_opcode_t *addr = (kprobe_opcode_t *)instruction_pointer(regs);
struct kprobe_ctlblk *kcb;
/*
* We don't want to be preempted for the entire
* duration of kprobe processing
*/
preempt_disable();
kcb = get_kprobe_ctlblk();
/* Handle recursion cases */
if (kprobe_running()) {
p = get_kprobe(addr);
if (p) {
if ((kcb->kprobe_status == KPROBE_HIT_SS) &&
(p->ainsn.inst_flag == INST_FLAG_BREAK_INST)) {
ia64_psr(regs)->ss = 0;
goto no_kprobe;
}
/* We have reentered the pre_kprobe_handler(), since
* another probe was hit while within the handler.
* We here save the original kprobes variables and
* just single step on the instruction of the new probe
* without calling any user handlers.
*/
save_previous_kprobe(kcb);
set_current_kprobe(p, kcb);
kprobes_inc_nmissed_count(p);
prepare_ss(p, regs);
kcb->kprobe_status = KPROBE_REENTER;
return 1;
} else if (args->err == __IA64_BREAK_JPROBE) {
/*
* jprobe instrumented function just completed
*/
p = __get_cpu_var(current_kprobe);
if (p->break_handler && p->break_handler(p, regs)) {
goto ss_probe;
}
} else if (!is_ia64_break_inst(regs)) {
/* The breakpoint instruction was removed by
* another cpu right after we hit, no further
* handling of this interrupt is appropriate
*/
ret = 1;
goto no_kprobe;
} else {
/* Not our break */
goto no_kprobe;
}
}
p = get_kprobe(addr);
if (!p) {
if (!is_ia64_break_inst(regs)) {
/*
* The breakpoint instruction was removed right
* after we hit it. Another cpu has removed
* either a probepoint or a debugger breakpoint
* at this address. In either case, no further
* handling of this interrupt is appropriate.
*/
ret = 1;
}
/* Not one of our break, let kernel handle it */
goto no_kprobe;
}
set_current_kprobe(p, kcb);
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
if (p->pre_handler && p->pre_handler(p, regs))
/*
* Our pre-handler is specifically requesting that we just
* do a return. This is used for both the jprobe pre-handler
* and the kretprobe trampoline
*/
return 1;
ss_probe:
prepare_ss(p, regs);
kcb->kprobe_status = KPROBE_HIT_SS;
return 1;
no_kprobe:
preempt_enable_no_resched();
return ret;
}
static int __kprobes post_kprobes_handler(struct pt_regs *regs)
{
struct kprobe *cur = kprobe_running();
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
if (!cur)
return 0;
if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
kcb->kprobe_status = KPROBE_HIT_SSDONE;
cur->post_handler(cur, regs, 0);
}
resume_execution(cur, regs);
/*Restore back the original saved kprobes variables and continue. */
if (kcb->kprobe_status == KPROBE_REENTER) {
restore_previous_kprobe(kcb);
goto out;
}
reset_current_kprobe();
out:
preempt_enable_no_resched();
return 1;
}
static int __kprobes kprobes_fault_handler(struct pt_regs *regs, int trapnr)
{
struct kprobe *cur = kprobe_running();
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
return 1;
if (kcb->kprobe_status & KPROBE_HIT_SS) {
resume_execution(cur, regs);
reset_current_kprobe();
preempt_enable_no_resched();
}
return 0;
}
int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data)
{
struct die_args *args = (struct die_args *)data;
int ret = NOTIFY_DONE;
switch(val) {
case DIE_BREAK:
/* err is break number from ia64_bad_break() */
if (args->err == 0x80200 || args->err == 0x80300 || args->err == 0)
if (pre_kprobes_handler(args))
ret = NOTIFY_STOP;
break;
case DIE_FAULT:
/* err is vector number from ia64_fault() */
if (args->err == 36)
if (post_kprobes_handler(args->regs))
ret = NOTIFY_STOP;
break;
case DIE_PAGE_FAULT:
/* kprobe_running() needs smp_processor_id() */
preempt_disable();
if (kprobe_running() &&
kprobes_fault_handler(args->regs, args->trapnr))
ret = NOTIFY_STOP;
preempt_enable();
default:
break;
}
return ret;
}
struct param_bsp_cfm {
unsigned long ip;
unsigned long *bsp;
unsigned long cfm;
};
static void ia64_get_bsp_cfm(struct unw_frame_info *info, void *arg)
{
unsigned long ip;
struct param_bsp_cfm *lp = arg;
do {
unw_get_ip(info, &ip);
if (ip == 0)
break;
if (ip == lp->ip) {
unw_get_bsp(info, (unsigned long*)&lp->bsp);
unw_get_cfm(info, (unsigned long*)&lp->cfm);
return;
}
} while (unw_unwind(info) >= 0);
lp->bsp = 0;
lp->cfm = 0;
return;
}
int __kprobes 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;
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
struct param_bsp_cfm pa;
int bytes;
/*
* Callee owns the argument space and could overwrite it, eg
* tail call optimization. So to be absolutely safe
* we save the argument space before transfering the control
* to instrumented jprobe function which runs in
* the process context
*/
pa.ip = regs->cr_iip;
unw_init_running(ia64_get_bsp_cfm, &pa);
bytes = (char *)ia64_rse_skip_regs(pa.bsp, pa.cfm & 0x3f)
- (char *)pa.bsp;
memcpy( kcb->jprobes_saved_stacked_regs,
pa.bsp,
bytes );
kcb->bsp = pa.bsp;
kcb->cfm = pa.cfm;
/* save architectural state */
kcb->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 __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
{
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
int bytes;
/* restoring architectural state */
*regs = kcb->jprobe_saved_regs;
/* restoring the original argument space */
flush_register_stack();
bytes = (char *)ia64_rse_skip_regs(kcb->bsp, kcb->cfm & 0x3f)
- (char *)kcb->bsp;
memcpy( kcb->bsp,
kcb->jprobes_saved_stacked_regs,
bytes );
invalidate_stacked_regs();
preempt_enable_no_resched();
return 1;
}
static struct kprobe trampoline_p = {
.pre_handler = trampoline_probe_handler
};
int __init arch_init_kprobes(void)
{
trampoline_p.addr =
(kprobe_opcode_t *)((struct fnptr *)kretprobe_trampoline)->ip;
return register_kprobe(&trampoline_p);
}
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