diff options
Diffstat (limited to 'arch/sparc64/kernel/kprobes.c')
| -rw-r--r-- | arch/sparc64/kernel/kprobes.c | 593 |
1 files changed, 0 insertions, 593 deletions
diff --git a/arch/sparc64/kernel/kprobes.c b/arch/sparc64/kernel/kprobes.c deleted file mode 100644 index 201a6e547e4..00000000000 --- a/arch/sparc64/kernel/kprobes.c +++ /dev/null @@ -1,593 +0,0 @@ -/* arch/sparc64/kernel/kprobes.c - * - * Copyright (C) 2004 David S. Miller <davem@davemloft.net> - */ - -#include <linux/kernel.h> -#include <linux/kprobes.h> -#include <linux/module.h> -#include <linux/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 - * 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. - */ - -DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; -DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); - -struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}}; - -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 __kprobes arch_arm_kprobe(struct kprobe *p) -{ - *p->addr = BREAKPOINT_INSTRUCTION; - flushi(p->addr); -} - -void __kprobes arch_disarm_kprobe(struct kprobe *p) -{ - *p->addr = p->opcode; - flushi(p->addr); -} - -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 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 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) -{ - 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 = kcb->kprobe_orig_tnpc; - } else { - regs->tpc = (unsigned long) &p->ainsn.insn[0]; - regs->tnpc = (unsigned long) &p->ainsn.insn[1]; - } -} - -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()) { - p = get_kprobe(addr); - if (p) { - if (kcb->kprobe_status == KPROBE_HIT_SS) { - regs->tstate = ((regs->tstate & ~TSTATE_PIL) | - kcb->kprobe_orig_tstate_pil); - 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); - kcb->kprobe_status = KPROBE_REENTER; - prepare_singlestep(p, regs, kcb); - return 1; - } else { - 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; - } - goto no_kprobe; - } - - p = get_kprobe(addr); - if (!p) { - 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; - } - - 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, kcb); - kcb->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. - * - * 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 __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 (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 + (regs->tnpc - ainsn_addr)); - } - - /* 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 __kprobes retpc_fixup(struct pt_regs *regs, u32 insn, - unsigned long real_pc) -{ - unsigned long *slot = NULL; - - /* 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 */ - 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 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[0]. - * - * This function prepares to return from the post-single-step - * breakpoint trap. - */ -static void __kprobes resume_execution(struct kprobe *p, - struct pt_regs *regs, struct kprobe_ctlblk *kcb) -{ - u32 insn = p->ainsn.insn[0]; - - 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) | - kcb->kprobe_orig_tstate_pil); -} - -static int __kprobes post_kprobe_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, kcb); - - /*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 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; - - /* - * In case the user-specified fault handler returned - * zero, try to fix up. - */ - - 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 __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)) - ret = NOTIFY_STOP; - break; - case DIE_DEBUG_2: - if (post_kprobe_handler(args->regs)) - ret = NOTIFY_STOP; - break; - default: - break; - } - return ret; -} - -asmlinkage void __kprobes 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. */ -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(); - - memcpy(&(kcb->jprobe_saved_regs), regs, sizeof(*regs)); - - regs->tpc = (unsigned long) jp->entry; - regs->tnpc = ((unsigned long) jp->entry) + 0x4UL; - regs->tstate |= TSTATE_PIL; - - return 1; -} - -void __kprobes jprobe_return(void) -{ - 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" - : /* no outputs */ - : "r" (orig_fp)); -} - -extern void jprobe_return_trap_instruction(void); - -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) { - memcpy(regs, &(kcb->jprobe_saved_regs), sizeof(*regs)); - preempt_enable_no_resched(); - return 1; - } - return 0; -} - -/* The value stored in the return address register is actually 2 - * instructions before where the callee will return to. - * Sequences usually look something like this - * - * call some_function <--- return register points here - * nop <--- call delay slot - * whatever <--- where callee returns to - * - * To keep trampoline_probe_handler logic simpler, we normalize the - * value kept in ri->ret_addr so we don't need to keep adjusting it - * back and forth. - */ -void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, - struct pt_regs *regs) -{ - ri->ret_addr = (kprobe_opcode_t *)(regs->u_regs[UREG_RETPC] + 8); - - /* Replace the return addr with trampoline addr */ - regs->u_regs[UREG_RETPC] = - ((unsigned long)kretprobe_trampoline) - 8; -} - -/* - * Called when the probe at kretprobe trampoline is hit - */ -int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) -{ - struct kretprobe_instance *ri = NULL; - struct hlist_head *head, empty_rp; - struct hlist_node *node, *tmp; - unsigned long flags, orig_ret_address = 0; - unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline; - - INIT_HLIST_HEAD(&empty_rp); - kretprobe_hash_lock(current, &head, &flags); - - /* - * 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, &empty_rp); - - 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; - } - - kretprobe_assert(ri, orig_ret_address, trampoline_address); - regs->tpc = orig_ret_address; - regs->tnpc = orig_ret_address + 4; - - reset_current_kprobe(); - kretprobe_hash_unlock(current, &flags); - preempt_enable_no_resched(); - - hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) { - hlist_del(&ri->hlist); - kfree(ri); - } - /* - * 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; -} - -void kretprobe_trampoline_holder(void) -{ - asm volatile(".global kretprobe_trampoline\n" - "kretprobe_trampoline:\n" - "\tnop\n" - "\tnop\n"); -} -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); -} - -int __kprobes arch_trampoline_kprobe(struct kprobe *p) -{ - if (p->addr == (kprobe_opcode_t *)&kretprobe_trampoline) - return 1; - - return 0; -} |