kprobes: kretprobes simplifications

[platform/kernel/linux-starfive.git] / arch / powerpc / kernel / kprobes.c

diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 4657563..aed58e1 100644 (file)
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -30,8 +30,8 @@
 #include <linux/ptrace.h>
 #include <linux/preempt.h>
 #include <linux/module.h>
+#include <linux/kdebug.h>
 #include <asm/cacheflush.h>
-#include <asm/kdebug.h>
 #include <asm/sstep.h>
 #include <asm/uaccess.h>
 
@@ -46,8 +46,8 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
        if ((unsigned long)p->addr & 0x03) {
                printk("Attempt to register kprobe at an unaligned address\n");
                ret = -EINVAL;
-       } else if (IS_MTMSRD(insn) || IS_RFID(insn)) {
-               printk("Cannot register a kprobe on rfid or mtmsrd\n");
+       } else if (IS_MTMSRD(insn) || IS_RFID(insn) || IS_RFI(insn)) {
+               printk("Cannot register a kprobe on rfi/rfid or mtmsr[d]\n");
                ret = -EINVAL;
        }
 
@@ -59,12 +59,14 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
        }
 
        if (!ret) {
-               memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
+               memcpy(p->ainsn.insn, p->addr,
+                               MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
                p->opcode = *p->addr;
                flush_icache_range((unsigned long)p->ainsn.insn,
                        (unsigned long)p->ainsn.insn + sizeof(kprobe_opcode_t));
        }
 
+       p->ainsn.boostable = 0;
        return ret;
 }
 
@@ -124,22 +126,13 @@ static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
 }
 
 /* Called with kretprobe_lock held */
-void __kprobes arch_prepare_kretprobe(struct kretprobe *rp,
+void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
                                      struct pt_regs *regs)
 {
-       struct kretprobe_instance *ri;
-
-       if ((ri = get_free_rp_inst(rp)) != NULL) {
-               ri->rp = rp;
-               ri->task = current;
-               ri->ret_addr = (kprobe_opcode_t *)regs->link;
-
-               /* Replace the return addr with trampoline addr */
-               regs->link = (unsigned long)kretprobe_trampoline;
-               add_rp_inst(ri);
-       } else {
-               rp->nmissed++;
-       }
+       ri->ret_addr = (kprobe_opcode_t *)regs->link;
+
+       /* Replace the return addr with trampoline addr */
+       regs->link = (unsigned long)kretprobe_trampoline;
 }
 
 static int __kprobes kprobe_handler(struct pt_regs *regs)
@@ -232,6 +225,38 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
                return 1;
 
 ss_probe:
+       if (p->ainsn.boostable >= 0) {
+               unsigned int insn = *p->ainsn.insn;
+
+               /* regs->nip is also adjusted if emulate_step returns 1 */
+               ret = emulate_step(regs, insn);
+               if (ret > 0) {
+                       /*
+                        * Once this instruction has been boosted
+                        * successfully, set the boostable flag
+                        */
+                       if (unlikely(p->ainsn.boostable == 0))
+                               p->ainsn.boostable = 1;
+
+                       if (p->post_handler)
+                               p->post_handler(p, regs, 0);
+
+                       kcb->kprobe_status = KPROBE_HIT_SSDONE;
+                       reset_current_kprobe();
+                       preempt_enable_no_resched();
+                       return 1;
+               } else if (ret < 0) {
+                       /*
+                        * We don't allow kprobes on mtmsr(d)/rfi(d), etc.
+                        * So, we should never get here... but, its still
+                        * good to catch them, just in case...
+                        */
+                       printk("Can't step on instruction %x\n", insn);
+                       BUG();
+               } else if (ret == 0)
+                       /* This instruction can't be boosted */
+                       p->ainsn.boostable = -1;
+       }
        prepare_singlestep(p, regs);
        kcb->kprobe_status = KPROBE_HIT_SS;
        return 1;
@@ -302,7 +327,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
                        break;
        }
 
-       BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address));
+       kretprobe_assert(ri, orig_ret_address, trampoline_address);
        regs->nip = orig_ret_address;
 
        reset_current_kprobe();
@@ -483,8 +508,12 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
        memcpy(&kcb->jprobe_saved_regs, regs, sizeof(struct pt_regs));
 
        /* setup return addr to the jprobe handler routine */
+#ifdef CONFIG_PPC64
        regs->nip = (unsigned long)(((func_descr_t *)jp->entry)->entry);
        regs->gpr[2] = (unsigned long)(((func_descr_t *)jp->entry)->toc);
+#else
+       regs->nip = (unsigned long)jp->entry;
+#endif
 
        return 1;
 }