mirror of
https://github.com/torvalds/linux.git
synced 2024-11-25 13:41:51 +00:00
1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
395 lines
10 KiB
C
395 lines
10 KiB
C
/* arch/sparc64/kernel/kprobes.c
|
|
*
|
|
* Copyright (C) 2004 David S. Miller <davem@davemloft.net>
|
|
*/
|
|
|
|
#include <linux/config.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/kprobes.h>
|
|
|
|
#include <asm/kdebug.h>
|
|
#include <asm/signal.h>
|
|
|
|
/* We do not have hardware single-stepping on sparc64.
|
|
* So we implement software single-stepping with breakpoint
|
|
* traps. The top-level scheme is similar to that used
|
|
* in the x86 kprobes implementation.
|
|
*
|
|
* In the kprobe->ainsn.insn[] array we store the original
|
|
* instruction at index zero and a break instruction at
|
|
* index one.
|
|
*
|
|
* When we hit a kprobe we:
|
|
* - Run the pre-handler
|
|
* - Remember "regs->tnpc" and interrupt level stored in
|
|
* "regs->tstate" so we can restore them later
|
|
* - Disable PIL interrupts
|
|
* - Set regs->tpc to point to kprobe->ainsn.insn[0]
|
|
* - Set regs->tnpc to point to kprobe->ainsn.insn[1]
|
|
* - Mark that we are actively in a kprobe
|
|
*
|
|
* At this point we wait for the second breakpoint at
|
|
* kprobe->ainsn.insn[1] to hit. When it does we:
|
|
* - Run the post-handler
|
|
* - Set regs->tpc to "remembered" regs->tnpc stored above,
|
|
* restore the PIL interrupt level in "regs->tstate" as well
|
|
* - Make any adjustments necessary to regs->tnpc in order
|
|
* to handle relative branches correctly. See below.
|
|
* - Mark that we are no longer actively in a kprobe.
|
|
*/
|
|
|
|
int arch_prepare_kprobe(struct kprobe *p)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
void arch_copy_kprobe(struct kprobe *p)
|
|
{
|
|
p->ainsn.insn[0] = *p->addr;
|
|
p->ainsn.insn[1] = BREAKPOINT_INSTRUCTION_2;
|
|
}
|
|
|
|
void arch_remove_kprobe(struct kprobe *p)
|
|
{
|
|
}
|
|
|
|
/* kprobe_status settings */
|
|
#define KPROBE_HIT_ACTIVE 0x00000001
|
|
#define KPROBE_HIT_SS 0x00000002
|
|
|
|
static struct kprobe *current_kprobe;
|
|
static unsigned long current_kprobe_orig_tnpc;
|
|
static unsigned long current_kprobe_orig_tstate_pil;
|
|
static unsigned int kprobe_status;
|
|
|
|
static inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
|
|
{
|
|
current_kprobe_orig_tnpc = regs->tnpc;
|
|
current_kprobe_orig_tstate_pil = (regs->tstate & TSTATE_PIL);
|
|
regs->tstate |= TSTATE_PIL;
|
|
|
|
/*single step inline, if it a breakpoint instruction*/
|
|
if (p->opcode == BREAKPOINT_INSTRUCTION) {
|
|
regs->tpc = (unsigned long) p->addr;
|
|
regs->tnpc = current_kprobe_orig_tnpc;
|
|
} else {
|
|
regs->tpc = (unsigned long) &p->ainsn.insn[0];
|
|
regs->tnpc = (unsigned long) &p->ainsn.insn[1];
|
|
}
|
|
}
|
|
|
|
static inline void disarm_kprobe(struct kprobe *p, struct pt_regs *regs)
|
|
{
|
|
*p->addr = p->opcode;
|
|
flushi(p->addr);
|
|
|
|
regs->tpc = (unsigned long) p->addr;
|
|
regs->tnpc = current_kprobe_orig_tnpc;
|
|
regs->tstate = ((regs->tstate & ~TSTATE_PIL) |
|
|
current_kprobe_orig_tstate_pil);
|
|
}
|
|
|
|
static int kprobe_handler(struct pt_regs *regs)
|
|
{
|
|
struct kprobe *p;
|
|
void *addr = (void *) regs->tpc;
|
|
int ret = 0;
|
|
|
|
preempt_disable();
|
|
|
|
if (kprobe_running()) {
|
|
/* We *are* holding lock here, so this is safe.
|
|
* Disarm the probe we just hit, and ignore it.
|
|
*/
|
|
p = get_kprobe(addr);
|
|
if (p) {
|
|
if (kprobe_status == KPROBE_HIT_SS) {
|
|
regs->tstate = ((regs->tstate & ~TSTATE_PIL) |
|
|
current_kprobe_orig_tstate_pil);
|
|
unlock_kprobes();
|
|
goto no_kprobe;
|
|
}
|
|
disarm_kprobe(p, regs);
|
|
ret = 1;
|
|
} else {
|
|
p = current_kprobe;
|
|
if (p->break_handler && p->break_handler(p, regs))
|
|
goto ss_probe;
|
|
}
|
|
/* If it's not ours, can't be delete race, (we hold lock). */
|
|
goto no_kprobe;
|
|
}
|
|
|
|
lock_kprobes();
|
|
p = get_kprobe(addr);
|
|
if (!p) {
|
|
unlock_kprobes();
|
|
if (*(u32 *)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;
|
|
}
|
|
/* Not one of ours: let kernel handle it */
|
|
goto no_kprobe;
|
|
}
|
|
|
|
kprobe_status = KPROBE_HIT_ACTIVE;
|
|
current_kprobe = p;
|
|
if (p->pre_handler && p->pre_handler(p, regs))
|
|
return 1;
|
|
|
|
ss_probe:
|
|
prepare_singlestep(p, regs);
|
|
kprobe_status = KPROBE_HIT_SS;
|
|
return 1;
|
|
|
|
no_kprobe:
|
|
preempt_enable_no_resched();
|
|
return ret;
|
|
}
|
|
|
|
/* If INSN is a relative control transfer instruction,
|
|
* return the corrected branch destination value.
|
|
*
|
|
* The original INSN location was REAL_PC, it actually
|
|
* executed at PC and produced destination address NPC.
|
|
*/
|
|
static unsigned long relbranch_fixup(u32 insn, unsigned long real_pc,
|
|
unsigned long pc, unsigned long npc)
|
|
{
|
|
/* Branch not taken, no mods necessary. */
|
|
if (npc == pc + 0x4UL)
|
|
return real_pc + 0x4UL;
|
|
|
|
/* The three cases are call, branch w/prediction,
|
|
* and traditional branch.
|
|
*/
|
|
if ((insn & 0xc0000000) == 0x40000000 ||
|
|
(insn & 0xc1c00000) == 0x00400000 ||
|
|
(insn & 0xc1c00000) == 0x00800000) {
|
|
/* The instruction did all the work for us
|
|
* already, just apply the offset to the correct
|
|
* instruction location.
|
|
*/
|
|
return (real_pc + (npc - pc));
|
|
}
|
|
|
|
return real_pc + 0x4UL;
|
|
}
|
|
|
|
/* If INSN is an instruction which writes it's PC location
|
|
* into a destination register, fix that up.
|
|
*/
|
|
static void retpc_fixup(struct pt_regs *regs, u32 insn, unsigned long real_pc)
|
|
{
|
|
unsigned long *slot = NULL;
|
|
|
|
/* Simplest cast is call, which always uses %o7 */
|
|
if ((insn & 0xc0000000) == 0x40000000) {
|
|
slot = ®s->u_regs[UREG_I7];
|
|
}
|
|
|
|
/* Jmpl encodes the register inside of the opcode */
|
|
if ((insn & 0xc1f80000) == 0x81c00000) {
|
|
unsigned long rd = ((insn >> 25) & 0x1f);
|
|
|
|
if (rd <= 15) {
|
|
slot = ®s->u_regs[rd];
|
|
} else {
|
|
/* Hard case, it goes onto the stack. */
|
|
flushw_all();
|
|
|
|
rd -= 16;
|
|
slot = (unsigned long *)
|
|
(regs->u_regs[UREG_FP] + STACK_BIAS);
|
|
slot += rd;
|
|
}
|
|
}
|
|
if (slot != NULL)
|
|
*slot = real_pc;
|
|
}
|
|
|
|
/*
|
|
* Called after single-stepping. p->addr is the address of the
|
|
* instruction whose first byte has been replaced by the breakpoint
|
|
* instruction. To avoid the SMP problems that can occur when we
|
|
* temporarily put back the original opcode to single-step, we
|
|
* single-stepped a copy of the instruction. The address of this
|
|
* copy is p->ainsn.insn.
|
|
*
|
|
* This function prepares to return from the post-single-step
|
|
* breakpoint trap.
|
|
*/
|
|
static void resume_execution(struct kprobe *p, struct pt_regs *regs)
|
|
{
|
|
u32 insn = p->ainsn.insn[0];
|
|
|
|
regs->tpc = current_kprobe_orig_tnpc;
|
|
regs->tnpc = relbranch_fixup(insn,
|
|
(unsigned long) p->addr,
|
|
(unsigned long) &p->ainsn.insn[0],
|
|
regs->tnpc);
|
|
retpc_fixup(regs, insn, (unsigned long) p->addr);
|
|
|
|
regs->tstate = ((regs->tstate & ~TSTATE_PIL) |
|
|
current_kprobe_orig_tstate_pil);
|
|
}
|
|
|
|
static inline int post_kprobe_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;
|
|
}
|
|
|
|
/* Interrupts disabled, kprobe_lock held. */
|
|
static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
|
|
{
|
|
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;
|
|
}
|
|
|
|
/*
|
|
* Wrapper routine to for handling exceptions.
|
|
*/
|
|
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_DEBUG:
|
|
if (kprobe_handler(args->regs))
|
|
return NOTIFY_STOP;
|
|
break;
|
|
case DIE_DEBUG_2:
|
|
if (post_kprobe_handler(args->regs))
|
|
return NOTIFY_STOP;
|
|
break;
|
|
case DIE_GPF:
|
|
if (kprobe_running() &&
|
|
kprobe_fault_handler(args->regs, args->trapnr))
|
|
return NOTIFY_STOP;
|
|
break;
|
|
case DIE_PAGE_FAULT:
|
|
if (kprobe_running() &&
|
|
kprobe_fault_handler(args->regs, args->trapnr))
|
|
return NOTIFY_STOP;
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
asmlinkage void kprobe_trap(unsigned long trap_level, struct pt_regs *regs)
|
|
{
|
|
BUG_ON(trap_level != 0x170 && trap_level != 0x171);
|
|
|
|
if (user_mode(regs)) {
|
|
local_irq_enable();
|
|
bad_trap(regs, trap_level);
|
|
return;
|
|
}
|
|
|
|
/* trap_level == 0x170 --> ta 0x70
|
|
* trap_level == 0x171 --> ta 0x71
|
|
*/
|
|
if (notify_die((trap_level == 0x170) ? DIE_DEBUG : DIE_DEBUG_2,
|
|
(trap_level == 0x170) ? "debug" : "debug_2",
|
|
regs, 0, trap_level, SIGTRAP) != NOTIFY_STOP)
|
|
bad_trap(regs, trap_level);
|
|
}
|
|
|
|
/* Jprobes support. */
|
|
static struct pt_regs jprobe_saved_regs;
|
|
static struct pt_regs *jprobe_saved_regs_location;
|
|
static struct sparc_stackf jprobe_saved_stack;
|
|
|
|
int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
|
|
{
|
|
struct jprobe *jp = container_of(p, struct jprobe, kp);
|
|
|
|
jprobe_saved_regs_location = regs;
|
|
memcpy(&jprobe_saved_regs, regs, sizeof(*regs));
|
|
|
|
/* Save a whole stack frame, this gets arguments
|
|
* pushed onto the stack after using up all the
|
|
* arg registers.
|
|
*/
|
|
memcpy(&jprobe_saved_stack,
|
|
(char *) (regs->u_regs[UREG_FP] + STACK_BIAS),
|
|
sizeof(jprobe_saved_stack));
|
|
|
|
regs->tpc = (unsigned long) jp->entry;
|
|
regs->tnpc = ((unsigned long) jp->entry) + 0x4UL;
|
|
regs->tstate |= TSTATE_PIL;
|
|
|
|
return 1;
|
|
}
|
|
|
|
void jprobe_return(void)
|
|
{
|
|
preempt_enable_no_resched();
|
|
__asm__ __volatile__(
|
|
".globl jprobe_return_trap_instruction\n"
|
|
"jprobe_return_trap_instruction:\n\t"
|
|
"ta 0x70");
|
|
}
|
|
|
|
extern void jprobe_return_trap_instruction(void);
|
|
|
|
extern void __show_regs(struct pt_regs * regs);
|
|
|
|
int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
|
|
{
|
|
u32 *addr = (u32 *) regs->tpc;
|
|
|
|
if (addr == (u32 *) jprobe_return_trap_instruction) {
|
|
if (jprobe_saved_regs_location != regs) {
|
|
printk("JPROBE: Current regs (%p) does not match "
|
|
"saved regs (%p).\n",
|
|
regs, jprobe_saved_regs_location);
|
|
printk("JPROBE: Saved registers\n");
|
|
__show_regs(jprobe_saved_regs_location);
|
|
printk("JPROBE: Current registers\n");
|
|
__show_regs(regs);
|
|
BUG();
|
|
}
|
|
/* Restore old register state. Do pt_regs
|
|
* first so that UREG_FP is the original one for
|
|
* the stack frame restore.
|
|
*/
|
|
memcpy(regs, &jprobe_saved_regs, sizeof(*regs));
|
|
|
|
memcpy((char *) (regs->u_regs[UREG_FP] + STACK_BIAS),
|
|
&jprobe_saved_stack,
|
|
sizeof(jprobe_saved_stack));
|
|
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|