[PATCH] Kprobes: Track kprobe on a per_cpu basis - ppc64 changes
PPC64 changes to track kprobe execution on a per-cpu basis. We now track the kprobe state machine independently on each cpu using an arch specific kprobe control block. Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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@ -37,12 +37,8 @@
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#include <asm/sstep.h>
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#include <asm/sstep.h>
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static DECLARE_MUTEX(kprobe_mutex);
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static DECLARE_MUTEX(kprobe_mutex);
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DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
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static struct kprobe *current_kprobe;
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DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
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static unsigned long kprobe_status, kprobe_saved_msr;
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static struct kprobe *kprobe_prev;
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static unsigned long kprobe_status_prev, kprobe_saved_msr_prev;
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static struct pt_regs jprobe_saved_regs;
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int __kprobes arch_prepare_kprobe(struct kprobe *p)
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int __kprobes arch_prepare_kprobe(struct kprobe *p)
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{
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{
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@ -108,18 +104,25 @@ static inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
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regs->nip = (unsigned long)p->ainsn.insn;
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regs->nip = (unsigned long)p->ainsn.insn;
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}
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}
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static inline void save_previous_kprobe(void)
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static inline void save_previous_kprobe(struct kprobe_ctlblk *kcb)
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{
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{
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kprobe_prev = current_kprobe;
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kcb->prev_kprobe.kp = kprobe_running();
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kprobe_status_prev = kprobe_status;
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kcb->prev_kprobe.status = kcb->kprobe_status;
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kprobe_saved_msr_prev = kprobe_saved_msr;
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kcb->prev_kprobe.saved_msr = kcb->kprobe_saved_msr;
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}
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}
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static inline void restore_previous_kprobe(void)
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static inline void restore_previous_kprobe(struct kprobe_ctlblk *kcb)
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{
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{
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current_kprobe = kprobe_prev;
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__get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
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kprobe_status = kprobe_status_prev;
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kcb->kprobe_status = kcb->prev_kprobe.status;
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kprobe_saved_msr = kprobe_saved_msr_prev;
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kcb->kprobe_saved_msr = kcb->prev_kprobe.saved_msr;
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}
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static inline void set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
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struct kprobe_ctlblk *kcb)
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{
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__get_cpu_var(current_kprobe) = p;
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kcb->kprobe_saved_msr = regs->msr;
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}
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}
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void __kprobes arch_prepare_kretprobe(struct kretprobe *rp,
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void __kprobes arch_prepare_kretprobe(struct kretprobe *rp,
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@ -145,6 +148,7 @@ static inline int kprobe_handler(struct pt_regs *regs)
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struct kprobe *p;
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struct kprobe *p;
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int ret = 0;
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int ret = 0;
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unsigned int *addr = (unsigned int *)regs->nip;
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unsigned int *addr = (unsigned int *)regs->nip;
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struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
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/* Check we're not actually recursing */
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/* Check we're not actually recursing */
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if (kprobe_running()) {
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if (kprobe_running()) {
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@ -153,10 +157,10 @@ static inline int kprobe_handler(struct pt_regs *regs)
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p = get_kprobe(addr);
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p = get_kprobe(addr);
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if (p) {
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if (p) {
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kprobe_opcode_t insn = *p->ainsn.insn;
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kprobe_opcode_t insn = *p->ainsn.insn;
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if (kprobe_status == KPROBE_HIT_SS &&
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if (kcb->kprobe_status == KPROBE_HIT_SS &&
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is_trap(insn)) {
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is_trap(insn)) {
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regs->msr &= ~MSR_SE;
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regs->msr &= ~MSR_SE;
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regs->msr |= kprobe_saved_msr;
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regs->msr |= kcb->kprobe_saved_msr;
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unlock_kprobes();
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unlock_kprobes();
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goto no_kprobe;
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goto no_kprobe;
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}
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}
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@ -166,15 +170,15 @@ static inline int kprobe_handler(struct pt_regs *regs)
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* just single step on the instruction of the new probe
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* just single step on the instruction of the new probe
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* without calling any user handlers.
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* without calling any user handlers.
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*/
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*/
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save_previous_kprobe();
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save_previous_kprobe(kcb);
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current_kprobe = p;
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set_current_kprobe(p, regs, kcb);
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kprobe_saved_msr = regs->msr;
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kcb->kprobe_saved_msr = regs->msr;
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p->nmissed++;
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p->nmissed++;
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prepare_singlestep(p, regs);
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prepare_singlestep(p, regs);
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kprobe_status = KPROBE_REENTER;
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kcb->kprobe_status = KPROBE_REENTER;
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return 1;
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return 1;
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} else {
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} else {
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p = current_kprobe;
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p = __get_cpu_var(current_kprobe);
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if (p->break_handler && p->break_handler(p, regs)) {
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if (p->break_handler && p->break_handler(p, regs)) {
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goto ss_probe;
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goto ss_probe;
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}
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}
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@ -214,16 +218,15 @@ static inline int kprobe_handler(struct pt_regs *regs)
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* in post_kprobe_handler().
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* in post_kprobe_handler().
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*/
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*/
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preempt_disable();
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preempt_disable();
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kprobe_status = KPROBE_HIT_ACTIVE;
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kcb->kprobe_status = KPROBE_HIT_ACTIVE;
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current_kprobe = p;
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set_current_kprobe(p, regs, kcb);
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kprobe_saved_msr = regs->msr;
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if (p->pre_handler && p->pre_handler(p, regs))
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if (p->pre_handler && p->pre_handler(p, regs))
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/* handler has already set things up, so skip ss setup */
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/* handler has already set things up, so skip ss setup */
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return 1;
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return 1;
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ss_probe:
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ss_probe:
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prepare_singlestep(p, regs);
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prepare_singlestep(p, regs);
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kprobe_status = KPROBE_HIT_SS;
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kcb->kprobe_status = KPROBE_HIT_SS;
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return 1;
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return 1;
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no_kprobe:
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no_kprobe:
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@ -292,6 +295,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
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BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address));
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BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address));
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regs->nip = orig_ret_address;
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regs->nip = orig_ret_address;
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reset_current_kprobe();
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unlock_kprobes();
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unlock_kprobes();
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preempt_enable_no_resched();
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preempt_enable_no_resched();
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@ -324,22 +328,26 @@ static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
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static inline int post_kprobe_handler(struct pt_regs *regs)
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static inline int post_kprobe_handler(struct pt_regs *regs)
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{
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{
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if (!kprobe_running())
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struct kprobe *cur = kprobe_running();
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struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
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if (!cur)
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return 0;
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return 0;
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if ((kprobe_status != KPROBE_REENTER) && current_kprobe->post_handler) {
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if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
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kprobe_status = KPROBE_HIT_SSDONE;
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kcb->kprobe_status = KPROBE_HIT_SSDONE;
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current_kprobe->post_handler(current_kprobe, regs, 0);
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cur->post_handler(cur, regs, 0);
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}
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}
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resume_execution(current_kprobe, regs);
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resume_execution(cur, regs);
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regs->msr |= kprobe_saved_msr;
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regs->msr |= kcb->kprobe_saved_msr;
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/*Restore back the original saved kprobes variables and continue. */
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/*Restore back the original saved kprobes variables and continue. */
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if (kprobe_status == KPROBE_REENTER) {
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if (kcb->kprobe_status == KPROBE_REENTER) {
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restore_previous_kprobe();
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restore_previous_kprobe(kcb);
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goto out;
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goto out;
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}
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}
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reset_current_kprobe();
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unlock_kprobes();
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unlock_kprobes();
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out:
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out:
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preempt_enable_no_resched();
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preempt_enable_no_resched();
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@ -358,15 +366,18 @@ out:
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/* Interrupts disabled, kprobe_lock held. */
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/* Interrupts disabled, kprobe_lock held. */
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static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
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static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
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{
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{
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if (current_kprobe->fault_handler
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struct kprobe *cur = kprobe_running();
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&& current_kprobe->fault_handler(current_kprobe, regs, trapnr))
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struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
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if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
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return 1;
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return 1;
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if (kprobe_status & KPROBE_HIT_SS) {
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if (kcb->kprobe_status & KPROBE_HIT_SS) {
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resume_execution(current_kprobe, regs);
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resume_execution(cur, regs);
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regs->msr &= ~MSR_SE;
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regs->msr &= ~MSR_SE;
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regs->msr |= kprobe_saved_msr;
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regs->msr |= kcb->kprobe_saved_msr;
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reset_current_kprobe();
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unlock_kprobes();
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unlock_kprobes();
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preempt_enable_no_resched();
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preempt_enable_no_resched();
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}
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}
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@ -411,8 +422,9 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
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int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
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int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
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{
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{
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struct jprobe *jp = container_of(p, struct jprobe, kp);
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struct jprobe *jp = container_of(p, struct jprobe, kp);
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struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
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memcpy(&jprobe_saved_regs, regs, sizeof(struct pt_regs));
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memcpy(&kcb->jprobe_saved_regs, regs, sizeof(struct pt_regs));
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/* setup return addr to the jprobe handler routine */
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/* setup return addr to the jprobe handler routine */
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regs->nip = (unsigned long)(((func_descr_t *)jp->entry)->entry);
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regs->nip = (unsigned long)(((func_descr_t *)jp->entry)->entry);
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@ -432,12 +444,14 @@ void __kprobes jprobe_return_end(void)
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int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
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int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
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{
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{
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struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
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/*
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/*
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* FIXME - we should ideally be validating that we got here 'cos
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* FIXME - we should ideally be validating that we got here 'cos
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* of the "trap" in jprobe_return() above, before restoring the
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* of the "trap" in jprobe_return() above, before restoring the
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* saved regs...
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* saved regs...
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*/
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*/
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memcpy(regs, &jprobe_saved_regs, sizeof(struct pt_regs));
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memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs));
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return 1;
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return 1;
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}
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}
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*/
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*/
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#include <linux/types.h>
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#include <linux/types.h>
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#include <linux/ptrace.h>
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#include <linux/ptrace.h>
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#include <linux/percpu.h>
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struct pt_regs;
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struct pt_regs;
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kprobe_opcode_t *insn;
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kprobe_opcode_t *insn;
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};
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};
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struct prev_kprobe {
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struct kprobe *kp;
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unsigned long status;
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unsigned long saved_msr;
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};
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/* per-cpu kprobe control block */
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struct kprobe_ctlblk {
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unsigned long kprobe_status;
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unsigned long kprobe_saved_msr;
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struct pt_regs jprobe_saved_regs;
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struct prev_kprobe prev_kprobe;
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};
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#ifdef CONFIG_KPROBES
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#ifdef CONFIG_KPROBES
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extern int kprobe_exceptions_notify(struct notifier_block *self,
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extern int kprobe_exceptions_notify(struct notifier_block *self,
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unsigned long val, void *data);
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unsigned long val, void *data);
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