cb1a55ec49
There is no need to cast a kprobe_opcode_t pointer to a kprobe_opcode_t pointer. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Link: https://lore.kernel.org/r/fc22b990d869fc2005990159d8072ae2774b1396.1709326528.git.geert+renesas@glider.be Signed-off-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
448 lines
11 KiB
C
448 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Kernel probes (kprobes) for SuperH
|
|
*
|
|
* Copyright (C) 2007 Chris Smith <chris.smith@st.com>
|
|
* Copyright (C) 2006 Lineo Solutions, Inc.
|
|
*/
|
|
#include <linux/kprobes.h>
|
|
#include <linux/extable.h>
|
|
#include <linux/ptrace.h>
|
|
#include <linux/preempt.h>
|
|
#include <linux/kdebug.h>
|
|
#include <linux/slab.h>
|
|
#include <asm/cacheflush.h>
|
|
#include <linux/uaccess.h>
|
|
|
|
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
|
|
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
|
|
|
|
static DEFINE_PER_CPU(struct kprobe, saved_current_opcode);
|
|
static DEFINE_PER_CPU(struct kprobe, saved_next_opcode);
|
|
static DEFINE_PER_CPU(struct kprobe, saved_next_opcode2);
|
|
|
|
#define OPCODE_JMP(x) (((x) & 0xF0FF) == 0x402b)
|
|
#define OPCODE_JSR(x) (((x) & 0xF0FF) == 0x400b)
|
|
#define OPCODE_BRA(x) (((x) & 0xF000) == 0xa000)
|
|
#define OPCODE_BRAF(x) (((x) & 0xF0FF) == 0x0023)
|
|
#define OPCODE_BSR(x) (((x) & 0xF000) == 0xb000)
|
|
#define OPCODE_BSRF(x) (((x) & 0xF0FF) == 0x0003)
|
|
|
|
#define OPCODE_BF_S(x) (((x) & 0xFF00) == 0x8f00)
|
|
#define OPCODE_BT_S(x) (((x) & 0xFF00) == 0x8d00)
|
|
|
|
#define OPCODE_BF(x) (((x) & 0xFF00) == 0x8b00)
|
|
#define OPCODE_BT(x) (((x) & 0xFF00) == 0x8900)
|
|
|
|
#define OPCODE_RTS(x) (((x) & 0x000F) == 0x000b)
|
|
#define OPCODE_RTE(x) (((x) & 0xFFFF) == 0x002b)
|
|
|
|
int __kprobes arch_prepare_kprobe(struct kprobe *p)
|
|
{
|
|
kprobe_opcode_t opcode = *p->addr;
|
|
|
|
if (OPCODE_RTE(opcode))
|
|
return -EFAULT; /* Bad breakpoint */
|
|
|
|
memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
|
|
p->opcode = opcode;
|
|
|
|
return 0;
|
|
}
|
|
|
|
void __kprobes arch_arm_kprobe(struct kprobe *p)
|
|
{
|
|
*p->addr = BREAKPOINT_INSTRUCTION;
|
|
flush_icache_range((unsigned long)p->addr,
|
|
(unsigned long)p->addr + sizeof(kprobe_opcode_t));
|
|
}
|
|
|
|
void __kprobes arch_disarm_kprobe(struct kprobe *p)
|
|
{
|
|
*p->addr = p->opcode;
|
|
flush_icache_range((unsigned long)p->addr,
|
|
(unsigned long)p->addr + sizeof(kprobe_opcode_t));
|
|
}
|
|
|
|
int __kprobes arch_trampoline_kprobe(struct kprobe *p)
|
|
{
|
|
if (*p->addr == BREAKPOINT_INSTRUCTION)
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* If an illegal slot instruction exception occurs for an address
|
|
* containing a kprobe, remove the probe.
|
|
*
|
|
* Returns 0 if the exception was handled successfully, 1 otherwise.
|
|
*/
|
|
int __kprobes kprobe_handle_illslot(unsigned long pc)
|
|
{
|
|
struct kprobe *p = get_kprobe((kprobe_opcode_t *) pc + 1);
|
|
|
|
if (p != NULL) {
|
|
printk("Warning: removing kprobe from delay slot: 0x%.8x\n",
|
|
(unsigned int)pc + 2);
|
|
unregister_kprobe(p);
|
|
return 0;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
void __kprobes arch_remove_kprobe(struct kprobe *p)
|
|
{
|
|
struct kprobe *saved = this_cpu_ptr(&saved_next_opcode);
|
|
|
|
if (saved->addr) {
|
|
arch_disarm_kprobe(p);
|
|
arch_disarm_kprobe(saved);
|
|
|
|
saved->addr = NULL;
|
|
saved->opcode = 0;
|
|
|
|
saved = this_cpu_ptr(&saved_next_opcode2);
|
|
if (saved->addr) {
|
|
arch_disarm_kprobe(saved);
|
|
|
|
saved->addr = NULL;
|
|
saved->opcode = 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
|
|
{
|
|
kcb->prev_kprobe.kp = kprobe_running();
|
|
kcb->prev_kprobe.status = kcb->kprobe_status;
|
|
}
|
|
|
|
static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
|
|
{
|
|
__this_cpu_write(current_kprobe, kcb->prev_kprobe.kp);
|
|
kcb->kprobe_status = kcb->prev_kprobe.status;
|
|
}
|
|
|
|
static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
|
|
struct kprobe_ctlblk *kcb)
|
|
{
|
|
__this_cpu_write(current_kprobe, p);
|
|
}
|
|
|
|
/*
|
|
* Singlestep is implemented by disabling the current kprobe and setting one
|
|
* on the next instruction, following branches. Two probes are set if the
|
|
* branch is conditional.
|
|
*/
|
|
static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
|
|
{
|
|
__this_cpu_write(saved_current_opcode.addr, (kprobe_opcode_t *)regs->pc);
|
|
|
|
if (p != NULL) {
|
|
struct kprobe *op1, *op2;
|
|
|
|
arch_disarm_kprobe(p);
|
|
|
|
op1 = this_cpu_ptr(&saved_next_opcode);
|
|
op2 = this_cpu_ptr(&saved_next_opcode2);
|
|
|
|
if (OPCODE_JSR(p->opcode) || OPCODE_JMP(p->opcode)) {
|
|
unsigned int reg_nr = ((p->opcode >> 8) & 0x000F);
|
|
op1->addr = (kprobe_opcode_t *) regs->regs[reg_nr];
|
|
} else if (OPCODE_BRA(p->opcode) || OPCODE_BSR(p->opcode)) {
|
|
unsigned long disp = (p->opcode & 0x0FFF);
|
|
op1->addr =
|
|
(kprobe_opcode_t *) (regs->pc + 4 + disp * 2);
|
|
|
|
} else if (OPCODE_BRAF(p->opcode) || OPCODE_BSRF(p->opcode)) {
|
|
unsigned int reg_nr = ((p->opcode >> 8) & 0x000F);
|
|
op1->addr =
|
|
(kprobe_opcode_t *) (regs->pc + 4 +
|
|
regs->regs[reg_nr]);
|
|
|
|
} else if (OPCODE_RTS(p->opcode)) {
|
|
op1->addr = (kprobe_opcode_t *) regs->pr;
|
|
|
|
} else if (OPCODE_BF(p->opcode) || OPCODE_BT(p->opcode)) {
|
|
unsigned long disp = (p->opcode & 0x00FF);
|
|
/* case 1 */
|
|
op1->addr = p->addr + 1;
|
|
/* case 2 */
|
|
op2->addr =
|
|
(kprobe_opcode_t *) (regs->pc + 4 + disp * 2);
|
|
op2->opcode = *(op2->addr);
|
|
arch_arm_kprobe(op2);
|
|
|
|
} else if (OPCODE_BF_S(p->opcode) || OPCODE_BT_S(p->opcode)) {
|
|
unsigned long disp = (p->opcode & 0x00FF);
|
|
/* case 1 */
|
|
op1->addr = p->addr + 2;
|
|
/* case 2 */
|
|
op2->addr =
|
|
(kprobe_opcode_t *) (regs->pc + 4 + disp * 2);
|
|
op2->opcode = *(op2->addr);
|
|
arch_arm_kprobe(op2);
|
|
|
|
} else {
|
|
op1->addr = p->addr + 1;
|
|
}
|
|
|
|
op1->opcode = *(op1->addr);
|
|
arch_arm_kprobe(op1);
|
|
}
|
|
}
|
|
|
|
/* Called with kretprobe_lock held */
|
|
void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
|
|
struct pt_regs *regs)
|
|
{
|
|
ri->ret_addr = (kprobe_opcode_t *) regs->pr;
|
|
ri->fp = NULL;
|
|
|
|
/* Replace the return addr with trampoline addr */
|
|
regs->pr = (unsigned long)__kretprobe_trampoline;
|
|
}
|
|
|
|
static int __kprobes kprobe_handler(struct pt_regs *regs)
|
|
{
|
|
struct kprobe *p;
|
|
int ret = 0;
|
|
kprobe_opcode_t *addr = NULL;
|
|
struct kprobe_ctlblk *kcb;
|
|
|
|
/*
|
|
* We don't want to be preempted for the entire
|
|
* duration of kprobe processing
|
|
*/
|
|
preempt_disable();
|
|
kcb = get_kprobe_ctlblk();
|
|
|
|
addr = (kprobe_opcode_t *) (regs->pc);
|
|
|
|
/* Check we're not actually recursing */
|
|
if (kprobe_running()) {
|
|
p = get_kprobe(addr);
|
|
if (p) {
|
|
if (kcb->kprobe_status == KPROBE_HIT_SS &&
|
|
*p->ainsn.insn == BREAKPOINT_INSTRUCTION) {
|
|
goto no_kprobe;
|
|
}
|
|
/* We have reentered the 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, regs, kcb);
|
|
kprobes_inc_nmissed_count(p);
|
|
prepare_singlestep(p, regs);
|
|
kcb->kprobe_status = KPROBE_REENTER;
|
|
return 1;
|
|
}
|
|
goto no_kprobe;
|
|
}
|
|
|
|
p = get_kprobe(addr);
|
|
if (!p) {
|
|
/* Not one of ours: let kernel handle it */
|
|
if (*addr != BREAKPOINT_INSTRUCTION) {
|
|
/*
|
|
* 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;
|
|
}
|
|
|
|
goto no_kprobe;
|
|
}
|
|
|
|
set_current_kprobe(p, regs, kcb);
|
|
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
|
|
|
|
if (p->pre_handler && p->pre_handler(p, regs)) {
|
|
/* handler has already set things up, so skip ss setup */
|
|
reset_current_kprobe();
|
|
preempt_enable_no_resched();
|
|
return 1;
|
|
}
|
|
|
|
prepare_singlestep(p, regs);
|
|
kcb->kprobe_status = KPROBE_HIT_SS;
|
|
return 1;
|
|
|
|
no_kprobe:
|
|
preempt_enable_no_resched();
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* For function-return probes, init_kprobes() establishes a probepoint
|
|
* here. When a retprobed function returns, this probe is hit and
|
|
* trampoline_probe_handler() runs, calling the kretprobe's handler.
|
|
*/
|
|
static void __used kretprobe_trampoline_holder(void)
|
|
{
|
|
asm volatile (".globl __kretprobe_trampoline\n"
|
|
"__kretprobe_trampoline:\n\t"
|
|
"nop\n");
|
|
}
|
|
|
|
/*
|
|
* Called when we hit the probe point at __kretprobe_trampoline
|
|
*/
|
|
static int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
|
|
{
|
|
regs->pc = __kretprobe_trampoline_handler(regs, NULL);
|
|
|
|
return 1;
|
|
}
|
|
|
|
static int __kprobes post_kprobe_handler(struct pt_regs *regs)
|
|
{
|
|
struct kprobe *cur = kprobe_running();
|
|
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
|
|
kprobe_opcode_t *addr = NULL;
|
|
struct kprobe *p = NULL;
|
|
|
|
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);
|
|
}
|
|
|
|
p = this_cpu_ptr(&saved_next_opcode);
|
|
if (p->addr) {
|
|
arch_disarm_kprobe(p);
|
|
p->addr = NULL;
|
|
p->opcode = 0;
|
|
|
|
addr = __this_cpu_read(saved_current_opcode.addr);
|
|
__this_cpu_write(saved_current_opcode.addr, NULL);
|
|
|
|
p = get_kprobe(addr);
|
|
arch_arm_kprobe(p);
|
|
|
|
p = this_cpu_ptr(&saved_next_opcode2);
|
|
if (p->addr) {
|
|
arch_disarm_kprobe(p);
|
|
p->addr = NULL;
|
|
p->opcode = 0;
|
|
}
|
|
}
|
|
|
|
/* 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;
|
|
}
|
|
|
|
int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
|
|
{
|
|
struct kprobe *cur = kprobe_running();
|
|
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
|
|
const struct exception_table_entry *entry;
|
|
|
|
switch (kcb->kprobe_status) {
|
|
case KPROBE_HIT_SS:
|
|
case KPROBE_REENTER:
|
|
/*
|
|
* We are here because the instruction being single
|
|
* stepped caused a page fault. We reset the current
|
|
* kprobe, point the pc back to the probe address
|
|
* and allow the page fault handler to continue as a
|
|
* normal page fault.
|
|
*/
|
|
regs->pc = (unsigned long)cur->addr;
|
|
if (kcb->kprobe_status == KPROBE_REENTER)
|
|
restore_previous_kprobe(kcb);
|
|
else
|
|
reset_current_kprobe();
|
|
preempt_enable_no_resched();
|
|
break;
|
|
case KPROBE_HIT_ACTIVE:
|
|
case KPROBE_HIT_SSDONE:
|
|
/*
|
|
* In case the user-specified fault handler returned
|
|
* zero, try to fix up.
|
|
*/
|
|
if ((entry = search_exception_tables(regs->pc)) != NULL) {
|
|
regs->pc = entry->fixup;
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* fixup_exception() could not handle it,
|
|
* Let do_page_fault() fix it.
|
|
*/
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Wrapper routine to for handling exceptions.
|
|
*/
|
|
int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
|
|
unsigned long val, void *data)
|
|
{
|
|
struct kprobe *p = NULL;
|
|
struct die_args *args = (struct die_args *)data;
|
|
int ret = NOTIFY_DONE;
|
|
kprobe_opcode_t *addr = NULL;
|
|
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
|
|
|
|
addr = (kprobe_opcode_t *) (args->regs->pc);
|
|
if (val == DIE_TRAP &&
|
|
args->trapnr == (BREAKPOINT_INSTRUCTION & 0xff)) {
|
|
if (!kprobe_running()) {
|
|
if (kprobe_handler(args->regs)) {
|
|
ret = NOTIFY_STOP;
|
|
} else {
|
|
/* Not a kprobe trap */
|
|
ret = NOTIFY_DONE;
|
|
}
|
|
} else {
|
|
p = get_kprobe(addr);
|
|
if ((kcb->kprobe_status == KPROBE_HIT_SS) ||
|
|
(kcb->kprobe_status == KPROBE_REENTER)) {
|
|
if (post_kprobe_handler(args->regs))
|
|
ret = NOTIFY_STOP;
|
|
} else {
|
|
if (kprobe_handler(args->regs))
|
|
ret = NOTIFY_STOP;
|
|
}
|
|
}
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static struct kprobe trampoline_p = {
|
|
.addr = (kprobe_opcode_t *)&__kretprobe_trampoline,
|
|
.pre_handler = trampoline_probe_handler
|
|
};
|
|
|
|
int __init arch_init_kprobes(void)
|
|
{
|
|
return register_kprobe(&trampoline_p);
|
|
}
|