* Copyright (C) 2004 David S. Miller <davem@davemloft.net>
*/
-#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/kprobes.h>
-
+#include <linux/module.h>
#include <asm/kdebug.h>
#include <asm/signal.h>
+#include <asm/cacheflush.h>
+#include <asm/uaccess.h>
/* We do not have hardware single-stepping on sparc64.
* So we implement software single-stepping with breakpoint
* - Mark that we are no longer actively in a kprobe.
*/
-int arch_prepare_kprobe(struct kprobe *p)
+DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
+DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
+
+int __kprobes arch_prepare_kprobe(struct kprobe *p)
{
+ p->ainsn.insn[0] = *p->addr;
+ flushi(&p->ainsn.insn[0]);
+
+ p->ainsn.insn[1] = BREAKPOINT_INSTRUCTION_2;
+ flushi(&p->ainsn.insn[1]);
+
+ p->opcode = *p->addr;
return 0;
}
-void arch_copy_kprobe(struct kprobe *p)
+void __kprobes arch_arm_kprobe(struct kprobe *p)
{
- p->ainsn.insn[0] = *p->addr;
- p->ainsn.insn[1] = BREAKPOINT_INSTRUCTION_2;
+ *p->addr = BREAKPOINT_INSTRUCTION;
+ flushi(p->addr);
}
-void arch_remove_kprobe(struct kprobe *p)
+void __kprobes arch_disarm_kprobe(struct kprobe *p)
{
+ *p->addr = p->opcode;
+ flushi(p->addr);
}
-/* kprobe_status settings */
-#define KPROBE_HIT_ACTIVE 0x00000001
-#define KPROBE_HIT_SS 0x00000002
+static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+ kcb->prev_kprobe.kp = kprobe_running();
+ kcb->prev_kprobe.status = kcb->kprobe_status;
+ kcb->prev_kprobe.orig_tnpc = kcb->kprobe_orig_tnpc;
+ kcb->prev_kprobe.orig_tstate_pil = kcb->kprobe_orig_tstate_pil;
+}
-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 void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+ __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
+ kcb->kprobe_status = kcb->prev_kprobe.status;
+ kcb->kprobe_orig_tnpc = kcb->prev_kprobe.orig_tnpc;
+ kcb->kprobe_orig_tstate_pil = kcb->prev_kprobe.orig_tstate_pil;
+}
-static inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
+static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb)
+{
+ __get_cpu_var(current_kprobe) = p;
+ kcb->kprobe_orig_tnpc = regs->tnpc;
+ kcb->kprobe_orig_tstate_pil = (regs->tstate & TSTATE_PIL);
+}
+
+static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb)
{
- 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;
+ regs->tnpc = kcb->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)
+static int __kprobes kprobe_handler(struct pt_regs *regs)
{
struct kprobe *p;
void *addr = (void *) regs->tpc;
int ret = 0;
+ struct kprobe_ctlblk *kcb;
+ /*
+ * We don't want to be preempted for the entire
+ * duration of kprobe processing
+ */
preempt_disable();
+ kcb = get_kprobe_ctlblk();
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) {
+ if (kcb->kprobe_status == KPROBE_HIT_SS) {
regs->tstate = ((regs->tstate & ~TSTATE_PIL) |
- current_kprobe_orig_tstate_pil);
- unlock_kprobes();
+ kcb->kprobe_orig_tstate_pil);
goto no_kprobe;
}
- disarm_kprobe(p, regs);
- ret = 1;
+ /* 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);
+ kcb->kprobe_status = KPROBE_REENTER;
+ prepare_singlestep(p, regs, kcb);
+ return 1;
} else {
- p = current_kprobe;
+ if (*(u32 *)addr != BREAKPOINT_INSTRUCTION) {
+ /* 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;
+ }
+ p = __get_cpu_var(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
goto no_kprobe;
}
- kprobe_status = KPROBE_HIT_ACTIVE;
- current_kprobe = p;
+ set_current_kprobe(p, regs, kcb);
+ kcb->kprobe_status = KPROBE_HIT_ACTIVE;
if (p->pre_handler && p->pre_handler(p, regs))
return 1;
ss_probe:
- prepare_singlestep(p, regs);
- kprobe_status = KPROBE_HIT_SS;
+ prepare_singlestep(p, regs, kcb);
+ kcb->kprobe_status = KPROBE_HIT_SS;
return 1;
no_kprobe:
/* 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.
+ * regs->tpc and regs->tnpc still hold the values of the
+ * program counters at the time of trap due to the execution
+ * of the BREAKPOINT_INSTRUCTION_2 at p->ainsn.insn[1]
+ *
*/
-static unsigned long relbranch_fixup(u32 insn, unsigned long real_pc,
- unsigned long pc, unsigned long npc)
+static unsigned long __kprobes relbranch_fixup(u32 insn, struct kprobe *p,
+ struct pt_regs *regs)
{
+ unsigned long real_pc = (unsigned long) p->addr;
+
/* Branch not taken, no mods necessary. */
- if (npc == pc + 0x4UL)
- return real_pc + 0x4UL;
+ if (regs->tnpc == regs->tpc + 0x4UL)
+ return real_pc + 0x8UL;
/* The three cases are call, branch w/prediction,
* and traditional branch.
if ((insn & 0xc0000000) == 0x40000000 ||
(insn & 0xc1c00000) == 0x00400000 ||
(insn & 0xc1c00000) == 0x00800000) {
+ unsigned long ainsn_addr;
+
+ ainsn_addr = (unsigned long) &p->ainsn.insn[0];
+
/* 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 + (regs->tnpc - ainsn_addr));
}
- return real_pc + 0x4UL;
+ /* It is jmpl or some other absolute PC modification instruction,
+ * leave NPC as-is.
+ */
+ return regs->tnpc;
}
/* 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)
+static void __kprobes retpc_fixup(struct pt_regs *regs, u32 insn,
+ unsigned long real_pc)
{
unsigned long *slot = NULL;
- /* Simplest cast is call, which always uses %o7 */
+ /* Simplest case is 'call', which always uses %o7 */
if ((insn & 0xc0000000) == 0x40000000) {
slot = ®s->u_regs[UREG_I7];
}
- /* Jmpl encodes the register inside of the opcode */
+ /* 'jmpl' encodes the register inside of the opcode */
if ((insn & 0xc1f80000) == 0x81c00000) {
unsigned long rd = ((insn >> 25) & 0x1f);
/*
* Called after single-stepping. p->addr is the address of the
- * instruction whose first byte has been replaced by the breakpoint
+ * instruction which 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.
+ * copy is &p->ainsn.insn[0].
*
* This function prepares to return from the post-single-step
* breakpoint trap.
*/
-static void resume_execution(struct kprobe *p, struct pt_regs *regs)
+static void __kprobes resume_execution(struct kprobe *p,
+ struct pt_regs *regs, struct kprobe_ctlblk *kcb)
{
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);
+ regs->tnpc = relbranch_fixup(insn, p, regs);
+
+ /* This assignment must occur after relbranch_fixup() */
+ regs->tpc = kcb->kprobe_orig_tnpc;
+
retpc_fixup(regs, insn, (unsigned long) p->addr);
regs->tstate = ((regs->tstate & ~TSTATE_PIL) |
- current_kprobe_orig_tstate_pil);
+ kcb->kprobe_orig_tstate_pil);
}
-static inline int post_kprobe_handler(struct pt_regs *regs)
+static int __kprobes post_kprobe_handler(struct pt_regs *regs)
{
- if (!kprobe_running())
+ struct kprobe *cur = kprobe_running();
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ if (!cur)
return 0;
- if (current_kprobe->post_handler)
- current_kprobe->post_handler(current_kprobe, regs, 0);
+ if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
+ kcb->kprobe_status = KPROBE_HIT_SSDONE;
+ cur->post_handler(cur, regs, 0);
+ }
- resume_execution(current_kprobe, regs);
+ resume_execution(cur, regs, kcb);
- unlock_kprobes();
+ /*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;
}
-/* Interrupts disabled, kprobe_lock held. */
-static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+static int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
{
- if (current_kprobe->fault_handler
- && current_kprobe->fault_handler(current_kprobe, regs, trapnr))
- return 1;
+ 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 and the tpc points back to the probe address
+ * and allow the page fault handler to continue as a
+ * normal page fault.
+ */
+ regs->tpc = (unsigned long)cur->addr;
+ regs->tnpc = kcb->kprobe_orig_tnpc;
+ regs->tstate = ((regs->tstate & ~TSTATE_PIL) |
+ kcb->kprobe_orig_tstate_pil);
+ 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 accouting
+ * 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;
- if (kprobe_status & KPROBE_HIT_SS) {
- resume_execution(current_kprobe, regs);
+ /*
+ * In case the user-specified fault handler returned
+ * zero, try to fix up.
+ */
- unlock_kprobes();
- preempt_enable_no_resched();
+ entry = search_exception_tables(regs->tpc);
+ if (entry) {
+ regs->tpc = entry->fixup;
+ regs->tnpc = regs->tpc + 4;
+ 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 kprobe_exceptions_notify(struct notifier_block *self, unsigned long val,
- void *data)
+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;
+
+ if (args->regs && user_mode(args->regs))
+ return ret;
+
switch (val) {
case DIE_DEBUG:
if (kprobe_handler(args->regs))
- return NOTIFY_STOP;
+ ret = NOTIFY_STOP;
break;
case DIE_DEBUG_2:
if (post_kprobe_handler(args->regs))
- return NOTIFY_STOP;
+ ret = NOTIFY_STOP;
break;
case DIE_GPF:
- if (kprobe_running() &&
- kprobe_fault_handler(args->regs, args->trapnr))
- return NOTIFY_STOP;
- break;
case DIE_PAGE_FAULT:
+ /* kprobe_running() needs smp_processor_id() */
+ preempt_disable();
if (kprobe_running() &&
kprobe_fault_handler(args->regs, args->trapnr))
- return NOTIFY_STOP;
+ ret = NOTIFY_STOP;
+ preempt_enable();
break;
default:
break;
}
- return NOTIFY_DONE;
+ return ret;
}
-asmlinkage void kprobe_trap(unsigned long trap_level, struct pt_regs *regs)
+asmlinkage void __kprobes kprobe_trap(unsigned long trap_level,
+ struct pt_regs *regs)
{
BUG_ON(trap_level != 0x170 && trap_level != 0x171);
}
/* 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)
+int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
{
struct jprobe *jp = container_of(p, struct jprobe, kp);
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
- 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));
+ memcpy(&(kcb->jprobe_saved_regs), regs, sizeof(*regs));
regs->tpc = (unsigned long) jp->entry;
regs->tnpc = ((unsigned long) jp->entry) + 0x4UL;
return 1;
}
-void jprobe_return(void)
+void __kprobes jprobe_return(void)
{
- preempt_enable_no_resched();
- __asm__ __volatile__(
- ".globl jprobe_return_trap_instruction\n"
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+ register unsigned long orig_fp asm("g1");
+
+ orig_fp = kcb->jprobe_saved_regs.u_regs[UREG_FP];
+ __asm__ __volatile__("\n"
+"1: cmp %%sp, %0\n\t"
+ "blu,a,pt %%xcc, 1b\n\t"
+ " restore\n\t"
+ ".globl jprobe_return_trap_instruction\n"
"jprobe_return_trap_instruction:\n\t"
- "ta 0x70");
+ "ta 0x70"
+ : /* no outputs */
+ : "r" (orig_fp));
}
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)
+int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
{
u32 *addr = (u32 *) regs->tpc;
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
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));
-
+ memcpy(regs, &(kcb->jprobe_saved_regs), sizeof(*regs));
+ preempt_enable_no_resched();
return 1;
}
return 0;
}
+
+/* architecture specific initialization */
+int arch_init_kprobes(void)
+{
+ return 0;
+}
git://git.onelab.eu / linux-2.6.git / blobdiff