[PATCH] kprobes: enable booster on the preemptible kernel

[firefly-linux-kernel-4.4.55.git] / arch / i386 / kernel / kprobes.c

diff --git a/arch/i386/kernel/kprobes.c b/arch/i386/kernel/kprobes.c
index 7a97544f15a088f724b6ca7a1639b7c3e1f30b9f..af1d53344993cac32221d7209bf853bed4f5febc 100644 (file)
--- a/arch/i386/kernel/kprobes.c
+++ b/arch/i386/kernel/kprobes.c
@@ -184,7 +184,7 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p)
 void __kprobes arch_remove_kprobe(struct kprobe *p)
 {
        mutex_lock(&kprobe_mutex);
-       free_insn_slot(p->ainsn.insn);
+       free_insn_slot(p->ainsn.insn, (p->ainsn.boostable == 1));
        mutex_unlock(&kprobe_mutex);
 }
 
@@ -333,7 +333,7 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
                return 1;
 
 ss_probe:
-#ifndef CONFIG_PREEMPT
+#if !defined(CONFIG_PREEMPT) || defined(CONFIG_PM)
        if (p->ainsn.boostable == 1 && !p->post_handler){
                /* Boost up -- we can execute copied instructions directly */
                reset_current_kprobe();
@@ -361,8 +361,11 @@ no_kprobe:
        asm volatile ( ".global kretprobe_trampoline\n"
                        "kretprobe_trampoline: \n"
                        "       pushf\n"
-                       /* skip cs, eip, orig_eax, es, ds */
-                       "       subl $20, %esp\n"
+                       /* skip cs, eip, orig_eax */
+                       "       subl $12, %esp\n"
+                       "       pushl %gs\n"
+                       "       pushl %ds\n"
+                       "       pushl %es\n"
                        "       pushl %eax\n"
                        "       pushl %ebp\n"
                        "       pushl %edi\n"
@@ -373,10 +376,10 @@ no_kprobe:
                        "       movl %esp, %eax\n"
                        "       call trampoline_handler\n"
                        /* move eflags to cs */
-                       "       movl 48(%esp), %edx\n"
-                       "       movl %edx, 44(%esp)\n"
+                       "       movl 52(%esp), %edx\n"
+                       "       movl %edx, 48(%esp)\n"
                        /* save true return address on eflags */
-                       "       movl %eax, 48(%esp)\n"
+                       "       movl %eax, 52(%esp)\n"
                        "       popl %ebx\n"
                        "       popl %ecx\n"
                        "       popl %edx\n"
@@ -384,8 +387,8 @@ no_kprobe:
                        "       popl %edi\n"
                        "       popl %ebp\n"
                        "       popl %eax\n"
-                       /* skip eip, orig_eax, es, ds */
-                       "       addl $16, %esp\n"
+                       /* skip eip, orig_eax, es, ds, gs */
+                       "       addl $20, %esp\n"
                        "       popf\n"
                        "       ret\n");
 }
@@ -396,13 +399,18 @@ no_kprobe:
 fastcall void *__kprobes trampoline_handler(struct pt_regs *regs)
 {
        struct kretprobe_instance *ri = NULL;
-       struct hlist_head *head;
+       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);
        spin_lock_irqsave(&kretprobe_lock, flags);
        head = kretprobe_inst_table_head(current);
+       /* fixup registers */
+       regs->xcs = __KERNEL_CS;
+       regs->eip = trampoline_address;
+       regs->orig_eax = 0xffffffff;
 
        /*
         * It is possible to have multiple instances associated with a given
@@ -424,12 +432,13 @@ fastcall void *__kprobes trampoline_handler(struct pt_regs *regs)
 
                if (ri->rp && ri->rp->handler){
                        __get_cpu_var(current_kprobe) = &ri->rp->kp;
+                       get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE;
                        ri->rp->handler(ri, regs);
                        __get_cpu_var(current_kprobe) = NULL;
                }
 
                orig_ret_address = (unsigned long)ri->ret_addr;
-               recycle_rp_inst(ri);
+               recycle_rp_inst(ri, &empty_rp);
 
                if (orig_ret_address != trampoline_address)
                        /*
@@ -444,6 +453,10 @@ fastcall void *__kprobes trampoline_handler(struct pt_regs *regs)
 
        spin_unlock_irqrestore(&kretprobe_lock, flags);
 
+       hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
+               hlist_del(&ri->hlist);
+               kfree(ri);
+       }
        return (void*)orig_ret_address;
 }