powerpc/kprobes: Remove jprobe powerpc implementation

Remove arch dependent setjump/longjump functions
and unused fields in kprobe_ctlblk for jprobes
from arch/powerpc. This also reverts commits
related __is_active_jprobe() function.

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/152942445234.15209.12868722778364739753.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 9f3be5c8a4a391a10d7e4d4367313998b41c255d..674036db558b606fd80c2f3db10ca14c211f7ace 100644 (file)
--- a/arch/powerpc/include/asm/kprobes.h
+++ b/arch/powerpc/include/asm/kprobes.h
@@ -88,7 +88,6 @@ struct prev_kprobe {
 struct kprobe_ctlblk {
        unsigned long kprobe_status;
        unsigned long kprobe_saved_msr;
-       struct pt_regs jprobe_saved_regs;
        struct prev_kprobe prev_kprobe;
 };
 
@@ -104,7 +103,6 @@ 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 __is_active_jprobe(unsigned long addr);
 extern int skip_singlestep(struct kprobe *p, struct pt_regs *regs,
                           struct kprobe_ctlblk *kcb);
 #else

diff --git a/arch/powerpc/kernel/kprobes-ftrace.c b/arch/powerpc/kernel/kprobes-ftrace.c
index 7a1f99f1b47fa50436519f6c2eb1301c3bb5fc19..1b316331c2d9a3ad9e9dbdc49d0c6febf26ba71e 100644 (file)
--- a/arch/powerpc/kernel/kprobes-ftrace.c
+++ b/arch/powerpc/kernel/kprobes-ftrace.c
@@ -25,21 +25,6 @@
 #include <linux/preempt.h>
 #include <linux/ftrace.h>
 
-/*
- * This is called from ftrace code after invoking registered handlers to
- * disambiguate regs->nip changes done by jprobes and livepatch. We check if
- * there is an active jprobe at the provided address (mcount location).
- */
-int __is_active_jprobe(unsigned long addr)
-{
-       if (!preemptible()) {
-               struct kprobe *p = raw_cpu_read(current_kprobe);
-               return (p && (unsigned long)p->addr == addr) ? 1 : 0;
-       }
-
-       return 0;
-}
-
 static nokprobe_inline
 int __skip_singlestep(struct kprobe *p, struct pt_regs *regs,
                      struct kprobe_ctlblk *kcb, unsigned long orig_nip)

diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index e4c5bf33970bf8d0c025f5c20a968ec5a0f80436..600678fce0a86b71b60030a8ba39a84301548018 100644 (file)
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -611,60 +611,6 @@ unsigned long arch_deref_entry_point(void *entry)
 }
 NOKPROBE_SYMBOL(arch_deref_entry_point);
 
-int 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(&kcb->jprobe_saved_regs, regs, sizeof(struct pt_regs));
-
-       /* setup return addr to the jprobe handler routine */
-       regs->nip = arch_deref_entry_point(jp->entry);
-#ifdef PPC64_ELF_ABI_v2
-       regs->gpr[12] = (unsigned long)jp->entry;
-#elif defined(PPC64_ELF_ABI_v1)
-       regs->gpr[2] = (unsigned long)(((func_descr_t *)jp->entry)->toc);
-#endif
-
-       /*
-        * jprobes use jprobe_return() which skips the normal return
-        * path of the function, and this messes up the accounting of the
-        * function graph tracer.
-        *
-        * Pause function graph tracing while performing the jprobe function.
-        */
-       pause_graph_tracing();
-
-       return 1;
-}
-NOKPROBE_SYMBOL(setjmp_pre_handler);
-
-void __used jprobe_return(void)
-{
-       asm volatile("jprobe_return_trap:\n"
-                    "trap\n"
-                    ::: "memory");
-}
-NOKPROBE_SYMBOL(jprobe_return);
-
-int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
-{
-       struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
-
-       if (regs->nip != ppc_kallsyms_lookup_name("jprobe_return_trap")) {
-               pr_debug("longjmp_break_handler NIP (0x%lx) does not match jprobe_return_trap (0x%lx)\n",
-                               regs->nip, ppc_kallsyms_lookup_name("jprobe_return_trap"));
-               return 0;
-       }
-
-       memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs));
-       /* It's OK to start function graph tracing again */
-       unpause_graph_tracing();
-       preempt_enable_no_resched();
-       return 1;
-}
-NOKPROBE_SYMBOL(longjmp_break_handler);
-
 static struct kprobe trampoline_p = {
        .addr = (kprobe_opcode_t *) &kretprobe_trampoline,
        .pre_handler = trampoline_probe_handler

diff --git a/arch/powerpc/kernel/trace/ftrace_64_mprofile.S b/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
index 9a5b5a513604018b3ff878b41c2871e135d1e579..32476a6e4e9cea8e8a09bb8da4b80cbd8af5fef8 100644 (file)
--- a/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
+++ b/arch/powerpc/kernel/trace/ftrace_64_mprofile.S
@@ -104,39 +104,13 @@ ftrace_regs_call:
        bl      ftrace_stub
        nop
 
-       /* Load the possibly modified NIP */
-       ld      r15, _NIP(r1)
-
+       /* Load ctr with the possibly modified NIP */
+       ld      r3, _NIP(r1)
+       mtctr   r3
 #ifdef CONFIG_LIVEPATCH
-       cmpd    r14, r15        /* has NIP been altered? */
+       cmpd    r14, r3         /* has NIP been altered? */
 #endif
 
-#if defined(CONFIG_LIVEPATCH) && defined(CONFIG_KPROBES_ON_FTRACE)
-       /* NIP has not been altered, skip over further checks */
-       beq     1f
-
-       /* Check if there is an active jprobe on us */
-       subi    r3, r14, 4
-       bl      __is_active_jprobe
-       nop
-
-       /*
-        * If r3 == 1, then this is a kprobe/jprobe.
-        * else, this is livepatched function.
-        *
-        * The conditional branch for livepatch_handler below will use the
-        * result of this comparison. For kprobe/jprobe, we just need to branch to
-        * the new NIP, not call livepatch_handler. The branch below is bne, so we
-        * want CR0[EQ] to be true if this is a kprobe/jprobe. Which means we want
-        * CR0[EQ] = (r3 == 1).
-        */
-       cmpdi   r3, 1
-1:
-#endif
-
-       /* Load CTR with the possibly modified NIP */
-       mtctr   r15
-
        /* Restore gprs */
        REST_GPR(0,r1)
        REST_10GPRS(2,r1)
@@ -154,10 +128,7 @@ ftrace_regs_call:
        addi r1, r1, SWITCH_FRAME_SIZE
 
 #ifdef CONFIG_LIVEPATCH
-        /*
-        * Based on the cmpd or cmpdi above, if the NIP was altered and we're
-        * not on a kprobe/jprobe, then handle livepatch.
-        */
+        /* Based on the cmpd above, if the NIP was altered handle livepatch */
        bne-    livepatch_handler
 #endif