powerpc/kprobes: Don't call the ->break_handler() in powerpc kprobes code

Don't call the ->break_handler() from the powerpc kprobes code,
because it was only used by jprobes which got removed.

This also removes skip_singlestep() and embeds it in the
caller, kprobe_ftrace_handler(), which simplifies regs->nip
operation around there.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-arch@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Link: https://lore.kernel.org/lkml/152942477127.15209.8982613703787878618.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/powerpc/include/asm/kprobes.h b/arch/powerpc/include/asm/kprobes.h
index 674036db558b606fd80c2f3db10ca14c211f7ace..785c464b65888d575fce38c0732250a5bbea81f8 100644 (file)
--- a/arch/powerpc/include/asm/kprobes.h
+++ b/arch/powerpc/include/asm/kprobes.h
@@ -102,16 +102,6 @@ extern int kprobe_exceptions_notify(struct notifier_block *self,
 extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr);
 extern int kprobe_handler(struct pt_regs *regs);
 extern int kprobe_post_handler(struct pt_regs *regs);
-#ifdef CONFIG_KPROBES_ON_FTRACE
-extern int skip_singlestep(struct kprobe *p, struct pt_regs *regs,
-                          struct kprobe_ctlblk *kcb);
-#else
-static inline int skip_singlestep(struct kprobe *p, struct pt_regs *regs,
-                                 struct kprobe_ctlblk *kcb)
-{
-       return 0;
-}
-#endif
 #else
 static inline int kprobe_handler(struct pt_regs *regs) { return 0; }
 static inline int kprobe_post_handler(struct pt_regs *regs) { return 0; }

diff --git a/arch/powerpc/kernel/kprobes-ftrace.c b/arch/powerpc/kernel/kprobes-ftrace.c
index 1b316331c2d9a3ad9e9dbdc49d0c6febf26ba71e..070d1d862444337bfc4f3f461d4d591f95e7eb97 100644 (file)
--- a/arch/powerpc/kernel/kprobes-ftrace.c
+++ b/arch/powerpc/kernel/kprobes-ftrace.c
@@ -25,35 +25,6 @@
 #include <linux/preempt.h>
 #include <linux/ftrace.h>
 
-static nokprobe_inline
-int __skip_singlestep(struct kprobe *p, struct pt_regs *regs,
-                     struct kprobe_ctlblk *kcb, unsigned long orig_nip)
-{
-       /*
-        * Emulate singlestep (and also recover regs->nip)
-        * as if there is a nop
-        */
-       regs->nip = (unsigned long)p->addr + MCOUNT_INSN_SIZE;
-       if (unlikely(p->post_handler)) {
-               kcb->kprobe_status = KPROBE_HIT_SSDONE;
-               p->post_handler(p, regs, 0);
-       }
-       __this_cpu_write(current_kprobe, NULL);
-       if (orig_nip)
-               regs->nip = orig_nip;
-       return 1;
-}
-
-int skip_singlestep(struct kprobe *p, struct pt_regs *regs,
-                   struct kprobe_ctlblk *kcb)
-{
-       if (kprobe_ftrace(p))
-               return __skip_singlestep(p, regs, kcb, 0);
-       else
-               return 0;
-}
-NOKPROBE_SYMBOL(skip_singlestep);
-
 /* Ftrace callback handler for kprobes */
 void kprobe_ftrace_handler(unsigned long nip, unsigned long parent_nip,
                           struct ftrace_ops *ops, struct pt_regs *regs)
@@ -71,8 +42,6 @@ void kprobe_ftrace_handler(unsigned long nip, unsigned long parent_nip,
        if (kprobe_running()) {
                kprobes_inc_nmissed_count(p);
        } else {
-               unsigned long orig_nip = regs->nip;
-
                /*
                 * On powerpc, NIP is *before* this instruction for the
                 * pre handler
@@ -81,9 +50,18 @@ void kprobe_ftrace_handler(unsigned long nip, unsigned long parent_nip,
 
                __this_cpu_write(current_kprobe, p);
                kcb->kprobe_status = KPROBE_HIT_ACTIVE;
-               if (!p->pre_handler || !p->pre_handler(p, regs))
-                       __skip_singlestep(p, regs, kcb, orig_nip);
-               else {
+               if (!p->pre_handler || !p->pre_handler(p, regs)) {
+                       /*
+                        * Emulate singlestep (and also recover regs->nip)
+                        * as if there is a nop
+                        */
+                       regs->nip += MCOUNT_INSN_SIZE;
+                       if (unlikely(p->post_handler)) {
+                               kcb->kprobe_status = KPROBE_HIT_SSDONE;
+                               p->post_handler(p, regs, 0);
+                       }
+                       __this_cpu_write(current_kprobe, NULL);
+               } else {
                        /*
                         * If pre_handler returns !0, it sets regs->nip and
                         * resets current kprobe. In this case, we should not

diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 600678fce0a86b71b60030a8ba39a84301548018..f06747e2e70de6f019858ea8683e4743eb96126b 100644 (file)
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -317,25 +317,17 @@ int kprobe_handler(struct pt_regs *regs)
                        }
                        prepare_singlestep(p, regs);
                        return 1;
-               } else {
-                       if (*addr != BREAKPOINT_INSTRUCTION) {
-                               /* If trap variant, then it belongs not to us */
-                               kprobe_opcode_t cur_insn = *addr;
-                               if (is_trap(cur_insn))
-                                       goto no_kprobe;
-                               /* The breakpoint instruction was removed by
-                                * another cpu right after we hit, no further
-                                * handling of this interrupt is appropriate
-                                */
-                               ret = 1;
+               } else if (*addr != BREAKPOINT_INSTRUCTION) {
+                       /* If trap variant, then it belongs not to us */
+                       kprobe_opcode_t cur_insn = *addr;
+
+                       if (is_trap(cur_insn))
                                goto no_kprobe;
-                       }
-                       p = __this_cpu_read(current_kprobe);
-                       if (p->break_handler && p->break_handler(p, regs)) {
-                               if (!skip_singlestep(p, regs, kcb))
-                                       goto ss_probe;
-                               ret = 1;
-                       }
+                       /* The breakpoint instruction was removed by
+                        * another cpu right after we hit, no further
+                        * handling of this interrupt is appropriate
+                        */
+                       ret = 1;
                }
                goto no_kprobe;
        }
@@ -350,7 +342,7 @@ int kprobe_handler(struct pt_regs *regs)
                         */
                        kprobe_opcode_t cur_insn = *addr;
                        if (is_trap(cur_insn))
-                               goto no_kprobe;
+                               goto no_kprobe;
                        /*
                         * The breakpoint instruction was removed right
                         * after we hit it.  Another cpu has removed
@@ -370,7 +362,6 @@ int kprobe_handler(struct pt_regs *regs)
                /* handler has already set things up, so skip ss setup */
                return 1;
 
-ss_probe:
        if (p->ainsn.boostable >= 0) {
                ret = try_to_emulate(p, regs);