From 0dc036c91ac11b2b76bb91b59d8c7af919aa4a8d Mon Sep 17 00:00:00 2001 From: Ananth N Mavinakayanahalli Date: Mon, 7 Nov 2005 01:00:10 -0800 Subject: [PATCH] [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 Signed-off-by: Anil S Keshavamurthy Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/ppc64/kernel/kprobes.c | 94 ++++++++++++++++++++--------------- include/asm-powerpc/kprobes.h | 15 ++++++ 2 files changed, 69 insertions(+), 40 deletions(-) diff --git a/arch/ppc64/kernel/kprobes.c b/arch/ppc64/kernel/kprobes.c index 6071ee99f5cb..3f89f3e5584a 100644 --- a/arch/ppc64/kernel/kprobes.c +++ b/arch/ppc64/kernel/kprobes.c @@ -37,12 +37,8 @@ #include static DECLARE_MUTEX(kprobe_mutex); - -static struct kprobe *current_kprobe; -static unsigned long kprobe_status, kprobe_saved_msr; -static struct kprobe *kprobe_prev; -static unsigned long kprobe_status_prev, kprobe_saved_msr_prev; -static struct pt_regs jprobe_saved_regs; +DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL; +DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk); int __kprobes arch_prepare_kprobe(struct kprobe *p) { @@ -108,18 +104,25 @@ static inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs) regs->nip = (unsigned long)p->ainsn.insn; } -static inline void save_previous_kprobe(void) +static inline void save_previous_kprobe(struct kprobe_ctlblk *kcb) +{ + kcb->prev_kprobe.kp = kprobe_running(); + kcb->prev_kprobe.status = kcb->kprobe_status; + kcb->prev_kprobe.saved_msr = kcb->kprobe_saved_msr; +} + +static inline void restore_previous_kprobe(struct kprobe_ctlblk *kcb) { - kprobe_prev = current_kprobe; - kprobe_status_prev = kprobe_status; - kprobe_saved_msr_prev = kprobe_saved_msr; + __get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp; + kcb->kprobe_status = kcb->prev_kprobe.status; + kcb->kprobe_saved_msr = kcb->prev_kprobe.saved_msr; } -static inline void restore_previous_kprobe(void) +static inline void set_current_kprobe(struct kprobe *p, struct pt_regs *regs, + struct kprobe_ctlblk *kcb) { - current_kprobe = kprobe_prev; - kprobe_status = kprobe_status_prev; - kprobe_saved_msr = kprobe_saved_msr_prev; + __get_cpu_var(current_kprobe) = p; + kcb->kprobe_saved_msr = regs->msr; } void __kprobes arch_prepare_kretprobe(struct kretprobe *rp, @@ -145,6 +148,7 @@ static inline int kprobe_handler(struct pt_regs *regs) struct kprobe *p; int ret = 0; unsigned int *addr = (unsigned int *)regs->nip; + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); /* Check we're not actually recursing */ if (kprobe_running()) { @@ -153,10 +157,10 @@ static inline int kprobe_handler(struct pt_regs *regs) p = get_kprobe(addr); if (p) { kprobe_opcode_t insn = *p->ainsn.insn; - if (kprobe_status == KPROBE_HIT_SS && + if (kcb->kprobe_status == KPROBE_HIT_SS && is_trap(insn)) { regs->msr &= ~MSR_SE; - regs->msr |= kprobe_saved_msr; + regs->msr |= kcb->kprobe_saved_msr; unlock_kprobes(); goto no_kprobe; } @@ -166,15 +170,15 @@ static inline int kprobe_handler(struct pt_regs *regs) * just single step on the instruction of the new probe * without calling any user handlers. */ - save_previous_kprobe(); - current_kprobe = p; - kprobe_saved_msr = regs->msr; + save_previous_kprobe(kcb); + set_current_kprobe(p, regs, kcb); + kcb->kprobe_saved_msr = regs->msr; 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; } @@ -214,16 +218,15 @@ static inline int kprobe_handler(struct pt_regs *regs) * in post_kprobe_handler(). */ preempt_disable(); - kprobe_status = KPROBE_HIT_ACTIVE; - current_kprobe = p; - kprobe_saved_msr = regs->msr; + kcb->kprobe_status = KPROBE_HIT_ACTIVE; + set_current_kprobe(p, regs, kcb); if (p->pre_handler && p->pre_handler(p, regs)) /* handler has already set things up, so skip ss setup */ return 1; ss_probe: prepare_singlestep(p, regs); - kprobe_status = KPROBE_HIT_SS; + kcb->kprobe_status = KPROBE_HIT_SS; return 1; no_kprobe: @@ -292,6 +295,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address)); regs->nip = orig_ret_address; + reset_current_kprobe(); unlock_kprobes(); preempt_enable_no_resched(); @@ -324,22 +328,26 @@ 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->msr |= kprobe_saved_msr; + resume_execution(cur, regs); + regs->msr |= kcb->kprobe_saved_msr; /*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(); @@ -358,15 +366,18 @@ 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); + if (kcb->kprobe_status & KPROBE_HIT_SS) { + resume_execution(cur, regs); regs->msr &= ~MSR_SE; - regs->msr |= kprobe_saved_msr; + regs->msr |= kcb->kprobe_saved_msr; + reset_current_kprobe(); unlock_kprobes(); preempt_enable_no_resched(); } @@ -411,8 +422,9 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self, 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(&jprobe_saved_regs, regs, sizeof(struct pt_regs)); + memcpy(&kcb->jprobe_saved_regs, regs, sizeof(struct pt_regs)); /* setup return addr to the jprobe handler routine */ regs->nip = (unsigned long)(((func_descr_t *)jp->entry)->entry); @@ -432,12 +444,14 @@ void __kprobes jprobe_return_end(void) int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) { + struct kprobe_ctlblk *kcb = get_kprobe_ctlblk(); + /* * FIXME - we should ideally be validating that we got here 'cos * of the "trap" in jprobe_return() above, before restoring the * saved regs... */ - memcpy(regs, &jprobe_saved_regs, sizeof(struct pt_regs)); + memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs)); return 1; } diff --git a/include/asm-powerpc/kprobes.h b/include/asm-powerpc/kprobes.h index b2f09f17fbe0..6cd0a3bfa280 100644 --- a/include/asm-powerpc/kprobes.h +++ b/include/asm-powerpc/kprobes.h @@ -27,6 +27,7 @@ */ #include #include +#include struct pt_regs; @@ -53,6 +54,20 @@ struct arch_specific_insn { kprobe_opcode_t *insn; }; +struct prev_kprobe { + struct kprobe *kp; + unsigned long status; + unsigned long saved_msr; +}; + +/* per-cpu kprobe control block */ +struct kprobe_ctlblk { + unsigned long kprobe_status; + unsigned long kprobe_saved_msr; + struct pt_regs jprobe_saved_regs; + struct prev_kprobe prev_kprobe; +}; + #ifdef CONFIG_KPROBES extern int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val, void *data); -- 2.20.1