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Diffstat (limited to 'arch/ppc64/kernel/kprobes.c')
-rw-r--r--arch/ppc64/kernel/kprobes.c138
1 files changed, 73 insertions, 65 deletions
diff --git a/arch/ppc64/kernel/kprobes.c b/arch/ppc64/kernel/kprobes.c
index ed876a5178ae..511af54e6230 100644
--- a/arch/ppc64/kernel/kprobes.c
+++ b/arch/ppc64/kernel/kprobes.c
@@ -30,19 +30,14 @@
#include <linux/config.h>
#include <linux/kprobes.h>
#include <linux/ptrace.h>
-#include <linux/spinlock.h>
#include <linux/preempt.h>
#include <asm/cacheflush.h>
#include <asm/kdebug.h>
#include <asm/sstep.h>
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)
{
@@ -108,20 +103,28 @@ 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;
}
+/* Called with kretprobe_lock held */
void __kprobes arch_prepare_kretprobe(struct kretprobe *rp,
struct pt_regs *regs)
{
@@ -145,19 +148,24 @@ 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;
+
+ /*
+ * We don't want to be preempted for the entire
+ * duration of kprobe processing
+ */
+ preempt_disable();
+ kcb = get_kprobe_ctlblk();
/* Check we're not actually recursing */
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) {
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;
- unlock_kprobes();
+ regs->msr |= kcb->kprobe_saved_msr;
goto no_kprobe;
}
/* We have reentered the kprobe_handler(), since
@@ -166,27 +174,24 @@ 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;
}
}
- /* 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 (*addr != BREAKPOINT_INSTRUCTION) {
/*
* PowerPC has multiple variants of the "trap"
@@ -209,24 +214,19 @@ static inline int kprobe_handler(struct pt_regs *regs)
goto no_kprobe;
}
- 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;
- /*
- * This preempt_disable() matches the preempt_enable_no_resched()
- * in post_kprobe_handler().
- */
- preempt_disable();
+ kcb->kprobe_status = KPROBE_HIT_SS;
return 1;
no_kprobe:
+ preempt_enable_no_resched();
return ret;
}
@@ -251,9 +251,10 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
struct kretprobe_instance *ri = NULL;
struct hlist_head *head;
struct hlist_node *node, *tmp;
- unsigned long orig_ret_address = 0;
+ unsigned long flags, orig_ret_address = 0;
unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
+ spin_lock_irqsave(&kretprobe_lock, flags);
head = kretprobe_inst_table_head(current);
/*
@@ -292,12 +293,14 @@ 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;
- unlock_kprobes();
+ reset_current_kprobe();
+ spin_unlock_irqrestore(&kretprobe_lock, flags);
+ preempt_enable_no_resched();
/*
* By returning a non-zero value, we are telling
- * kprobe_handler() that we have handled unlocking
- * and re-enabling preemption.
+ * kprobe_handler() that we don't want the post_handler
+ * to run (and have re-enabled preemption)
*/
return 1;
}
@@ -323,23 +326,26 @@ 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;
}
- unlock_kprobes();
+ reset_current_kprobe();
out:
preempt_enable_no_resched();
@@ -354,19 +360,20 @@ out:
return 1;
}
-/* 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;
- unlock_kprobes();
+ reset_current_kprobe();
preempt_enable_no_resched();
}
return 0;
@@ -381,11 +388,6 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
struct die_args *args = (struct die_args *)data;
int ret = NOTIFY_DONE;
- /*
- * Interrupts are not disabled here. We need to disable
- * preemption, because kprobe_running() uses smp_processor_id().
- */
- preempt_disable();
switch (val) {
case DIE_BPT:
if (kprobe_handler(args->regs))
@@ -396,22 +398,25 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
ret = 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))
ret = NOTIFY_STOP;
+ preempt_enable();
break;
default:
break;
}
- preempt_enable_no_resched();
return ret;
}
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);
@@ -431,12 +436,15 @@ 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));
+ preempt_enable_no_resched();
return 1;
}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.