diff options
| -rw-r--r-- | arch/i386/kernel/kprobes.c | 126 | ||||
| -rw-r--r-- | include/asm-i386/kprobes.h | 17 |
2 files changed, 86 insertions, 57 deletions
diff --git a/arch/i386/kernel/kprobes.c b/arch/i386/kernel/kprobes.c index fd35039859e6..99565a66915d 100644 --- a/arch/i386/kernel/kprobes.c +++ b/arch/i386/kernel/kprobes.c @@ -37,16 +37,11 @@ #include <asm/kdebug.h> #include <asm/desc.h> -static struct kprobe *current_kprobe; -static unsigned long kprobe_status, kprobe_old_eflags, kprobe_saved_eflags; -static struct kprobe *kprobe_prev; -static unsigned long kprobe_status_prev, kprobe_old_eflags_prev, kprobe_saved_eflags_prev; -static struct pt_regs jprobe_saved_regs; -static long *jprobe_saved_esp; -/* copy of the kernel stack at the probe fire time */ -static kprobe_opcode_t jprobes_stack[MAX_STACK_SIZE]; void jprobe_return_end(void); +DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; +DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); + /* * returns non-zero if opcode modifies the interrupt flag. */ @@ -91,29 +86,30 @@ void __kprobes arch_remove_kprobe(struct kprobe *p) { } -static inline void save_previous_kprobe(void) +static inline void save_previous_kprobe(struct kprobe_ctlblk *kcb) { - kprobe_prev = current_kprobe; - kprobe_status_prev = kprobe_status; - kprobe_old_eflags_prev = kprobe_old_eflags; - kprobe_saved_eflags_prev = kprobe_saved_eflags; + kcb->prev_kprobe.kp = kprobe_running(); + kcb->prev_kprobe.status = kcb->kprobe_status; + kcb->prev_kprobe.old_eflags = kcb->kprobe_old_eflags; + kcb->prev_kprobe.saved_eflags = kcb->kprobe_saved_eflags; } -static inline void restore_previous_kprobe(void) +static inline void restore_previous_kprobe(struct kprobe_ctlblk *kcb) { - current_kprobe = kprobe_prev; - kprobe_status = kprobe_status_prev; - kprobe_old_eflags = kprobe_old_eflags_prev; - kprobe_saved_eflags = kprobe_saved_eflags_prev; + __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp; + kcb->kprobe_status = kcb->prev_kprobe.status; + kcb->kprobe_old_eflags = kcb->prev_kprobe.old_eflags; + kcb->kprobe_saved_eflags = kcb->prev_kprobe.saved_eflags; } -static inline void set_current_kprobe(struct kprobe *p, struct pt_regs *regs) +static inline void set_current_kprobe(struct kprobe *p, struct pt_regs *regs, + struct kprobe_ctlblk *kcb) { - current_kprobe = p; - kprobe_saved_eflags = kprobe_old_eflags + __get_cpu_var(current_kprobe) = p; + kcb->kprobe_saved_eflags = kcb->kprobe_old_eflags = (regs->eflags & (TF_MASK | IF_MASK)); if (is_IF_modifier(p->opcode)) - kprobe_saved_eflags &= ~IF_MASK; + kcb->kprobe_saved_eflags &= ~IF_MASK; } static inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs) @@ -157,6 +153,7 @@ static int __kprobes kprobe_handler(struct pt_regs *regs) int ret = 0; kprobe_opcode_t *addr = NULL; unsigned long *lp; + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); /* Check if the application is using LDT entry for its code segment and * calculate the address by reading the base address from the LDT entry. @@ -175,10 +172,10 @@ static int __kprobes kprobe_handler(struct pt_regs *regs) 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 && *p->ainsn.insn == BREAKPOINT_INSTRUCTION) { regs->eflags &= ~TF_MASK; - regs->eflags |= kprobe_saved_eflags; + regs->eflags |= kcb->kprobe_saved_eflags; unlock_kprobes(); goto no_kprobe; } @@ -188,14 +185,14 @@ static int __kprobes kprobe_handler(struct pt_regs *regs) * just single step on the instruction of the new probe * without calling any user handlers. */ - save_previous_kprobe(); - set_current_kprobe(p, regs); + save_previous_kprobe(kcb); + set_current_kprobe(p, regs, kcb); p->nmissed++; prepare_singlestep(p, regs); - kprobe_status = KPROBE_REENTER; + kcb->kprobe_status = KPROBE_REENTER; return 1; } else { - p = current_kprobe; + p = __get_cpu_var(current_kprobe); if (p->break_handler && p->break_handler(p, regs)) { goto ss_probe; } @@ -235,8 +232,8 @@ static int __kprobes kprobe_handler(struct pt_regs *regs) * in post_kprobe_handler() */ preempt_disable(); - kprobe_status = KPROBE_HIT_ACTIVE; - set_current_kprobe(p, regs); + 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 */ @@ -244,7 +241,7 @@ static int __kprobes kprobe_handler(struct pt_regs *regs) ss_probe: prepare_singlestep(p, regs); - kprobe_status = KPROBE_HIT_SS; + kcb->kprobe_status = KPROBE_HIT_SS; return 1; no_kprobe: @@ -312,6 +309,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address)); regs->eip = orig_ret_address; + reset_current_kprobe(); unlock_kprobes(); preempt_enable_no_resched(); @@ -345,7 +343,8 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) * that is atop the stack is the address following the copied instruction. * We need to make it the address following the original instruction. */ -static void __kprobes 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) { unsigned long *tos = (unsigned long *)®s->esp; unsigned long next_eip = 0; @@ -355,7 +354,7 @@ static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs) switch (p->ainsn.insn[0]) { case 0x9c: /* pushfl */ *tos &= ~(TF_MASK | IF_MASK); - *tos |= kprobe_old_eflags; + *tos |= kcb->kprobe_old_eflags; break; case 0xc3: /* ret/lret */ case 0xcb: @@ -400,22 +399,26 @@ static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs) */ static inline int 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 ((kprobe_status != KPROBE_REENTER) && current_kprobe->post_handler) { - kprobe_status = KPROBE_HIT_SSDONE; - 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); - regs->eflags |= kprobe_saved_eflags; + resume_execution(cur, regs, kcb); + regs->eflags |= kcb->kprobe_saved_eflags; /*Restore back the original saved kprobes variables and continue. */ - if (kprobe_status == KPROBE_REENTER) { - restore_previous_kprobe(); + if (kcb->kprobe_status == KPROBE_REENTER) { + restore_previous_kprobe(kcb); goto out; } + reset_current_kprobe(); unlock_kprobes(); out: preempt_enable_no_resched(); @@ -434,14 +437,17 @@ out: /* 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)) + struct kprobe *cur = kprobe_running(); + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); + + if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr)) return 1; - if (kprobe_status & KPROBE_HIT_SS) { - resume_execution(current_kprobe, regs); - regs->eflags |= kprobe_old_eflags; + if (kcb->kprobe_status & KPROBE_HIT_SS) { + resume_execution(cur, regs, kcb); + regs->eflags |= kcb->kprobe_old_eflags; + reset_current_kprobe(); unlock_kprobes(); preempt_enable_no_resched(); } @@ -484,10 +490,11 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) { struct jprobe *jp = container_of(p, struct jprobe, kp); unsigned long addr; + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); - jprobe_saved_regs = *regs; - jprobe_saved_esp = ®s->esp; - addr = (unsigned long)jprobe_saved_esp; + kcb->jprobe_saved_regs = *regs; + kcb->jprobe_saved_esp = ®s->esp; + addr = (unsigned long)(kcb->jprobe_saved_esp); /* * TBD: As Linus pointed out, gcc assumes that the callee @@ -496,7 +503,8 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) * we also save and restore enough stack bytes to cover * the argument area. */ - memcpy(jprobes_stack, (kprobe_opcode_t *) addr, MIN_STACK_SIZE(addr)); + memcpy(kcb->jprobes_stack, (kprobe_opcode_t *)addr, + MIN_STACK_SIZE(addr)); regs->eflags &= ~IF_MASK; regs->eip = (unsigned long)(jp->entry); return 1; @@ -504,34 +512,38 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) void __kprobes jprobe_return(void) { + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); + asm volatile (" xchgl %%ebx,%%esp \n" " int3 \n" " .globl jprobe_return_end \n" " jprobe_return_end: \n" " nop \n"::"b" - (jprobe_saved_esp):"memory"); + (kcb->jprobe_saved_esp):"memory"); } int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) { + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); u8 *addr = (u8 *) (regs->eip - 1); - unsigned long stack_addr = (unsigned long)jprobe_saved_esp; + unsigned long stack_addr = (unsigned long)(kcb->jprobe_saved_esp); struct jprobe *jp = container_of(p, struct jprobe, kp); if ((addr > (u8 *) jprobe_return) && (addr < (u8 *) jprobe_return_end)) { - if (®s->esp != jprobe_saved_esp) { + if (®s->esp != kcb->jprobe_saved_esp) { struct pt_regs *saved_regs = - container_of(jprobe_saved_esp, struct pt_regs, esp); + container_of(kcb->jprobe_saved_esp, + struct pt_regs, esp); printk("current esp %p does not match saved esp %p\n", - ®s->esp, jprobe_saved_esp); + ®s->esp, kcb->jprobe_saved_esp); printk("Saved registers for jprobe %p\n", jp); show_registers(saved_regs); printk("Current registers\n"); show_registers(regs); BUG(); } - *regs = jprobe_saved_regs; - memcpy((kprobe_opcode_t *) stack_addr, jprobes_stack, + *regs = kcb->jprobe_saved_regs; + memcpy((kprobe_opcode_t *) stack_addr, kcb->jprobes_stack, MIN_STACK_SIZE(stack_addr)); return 1; } diff --git a/include/asm-i386/kprobes.h b/include/asm-i386/kprobes.h index 8b6d3a90cd78..ca916a892877 100644 --- a/include/asm-i386/kprobes.h +++ b/include/asm-i386/kprobes.h @@ -49,6 +49,23 @@ struct arch_specific_insn { kprobe_opcode_t insn[MAX_INSN_SIZE]; }; +struct prev_kprobe { + struct kprobe *kp; + unsigned long status; + unsigned long old_eflags; + unsigned long saved_eflags; +}; + +/* per-cpu kprobe control block */ +struct kprobe_ctlblk { + unsigned long kprobe_status; + unsigned long kprobe_old_eflags; + unsigned long kprobe_saved_eflags; + long *jprobe_saved_esp; + struct pt_regs jprobe_saved_regs; + kprobe_opcode_t jprobes_stack[MAX_STACK_SIZE]; + struct prev_kprobe prev_kprobe; +}; /* trap3/1 are intr gates for kprobes. So, restore the status of IF, * if necessary, before executing the original int3/1 (trap) handler. |