mirror of https://github.com/Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
469 lines
12 KiB
469 lines
12 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
|
* Kernel probes (kprobes) for SuperH |
|
* |
|
* Copyright (C) 2007 Chris Smith <[email protected]> |
|
* 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 = *(kprobe_opcode_t *) (p->addr); |
|
|
|
if (OPCODE_RTE(opcode)) |
|
return -EFAULT; /* Bad breakpoint */ |
|
|
|
p->opcode = opcode; |
|
|
|
return 0; |
|
} |
|
|
|
void __kprobes arch_copy_kprobe(struct kprobe *p) |
|
{ |
|
memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t)); |
|
p->opcode = *p->addr; |
|
} |
|
|
|
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 (*(kprobe_opcode_t *)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 |
|
*/ |
|
int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) |
|
{ |
|
regs->pc = __kretprobe_trampoline_handler(regs, &kretprobe_trampoline, 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: |
|
/* |
|
* We increment the nmissed count for accounting, |
|
* we can also use npre/npostfault count for accounting |
|
* these specific fault cases. |
|
*/ |
|
kprobes_inc_nmissed_count(cur); |
|
|
|
/* |
|
* We come here because instructions in the pre/post |
|
* handler caused the page_fault, this could happen |
|
* if handler tries to access user space by |
|
* copy_from_user(), get_user() etc. Let the |
|
* user-specified handler try to fix it first. |
|
*/ |
|
if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr)) |
|
return 1; |
|
|
|
/* |
|
* 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); |
|
}
|
|
|