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From:   Sven Schnelle <svens@stackframe.org>
To:     linux-kernel@vger.kernel.org
Cc:     Sven Schnelle <svens@stackframe.org>,
        "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>,
        Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
        "David S. Miller" <davem@davemloft.net>,
        Masami Hiramatsu <mhiramat@kernel.org>
Subject: [PATCH] kprobes: fix compilation when KPROBE_EVENTS is enabled without kretpobes
Date:   Sat,  6 Apr 2019 17:55:43 +0200
Message-Id: <20190406155543.15353-1-svens@stackframe.org>
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Sender: linux-kernel-owner@vger.kernel.org
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While implementing kprobes on PA-RISC (without kretprobes) compilation
fails when CONFIG_KPROBE_EVENTS is enabled:

kernel/trace/trace_kprobe.o: in function `trace_kprobe_create':
kernel/trace/trace_kprobe.c:666: undefined reference to `kprobe_on_func_entry'
kernel/trace/trace_kprobe.o: in function `trace_kprobe_on_func_entry':
kernel/trace/trace_kprobe.c:167: undefined reference to `kprobe_on_func_entry'
kernel/trace/trace_kprobe.c:167: undefined reference to `kprobe_on_func_entry'
make: *** [Makefile:1029: vmlinux] Error 1

Given the fact that these functions have no dependencies on kretprobes i think
they should be moved out of the #ifdef CONFIG_KRETPROBES block.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
---
 kernel/kprobes.c | 39 ++++++++++++++++++++-------------------
 1 file changed, 20 insertions(+), 19 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index c83e54727131..10a7e67fea67 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1819,6 +1819,26 @@ unsigned long __weak arch_deref_entry_point(void *entry)
 	return (unsigned long)entry;
 }
 
+bool __weak arch_kprobe_on_func_entry(unsigned long offset)
+{
+	return !offset;
+}
+
+bool kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym,
+			  unsigned long offset)
+{
+	kprobe_opcode_t *kp_addr = _kprobe_addr(addr, sym, offset);
+
+	if (IS_ERR(kp_addr))
+		return false;
+
+	if (!kallsyms_lookup_size_offset((unsigned long)kp_addr, NULL, &offset) ||
+					 !arch_kprobe_on_func_entry(offset))
+		return false;
+
+	return true;
+}
+
 #ifdef CONFIG_KRETPROBES
 /*
  * This kprobe pre_handler is registered with every kretprobe. When probe
@@ -1875,25 +1895,6 @@ static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
 }
 NOKPROBE_SYMBOL(pre_handler_kretprobe);
 
-bool __weak arch_kprobe_on_func_entry(unsigned long offset)
-{
-	return !offset;
-}
-
-bool kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset)
-{
-	kprobe_opcode_t *kp_addr = _kprobe_addr(addr, sym, offset);
-
-	if (IS_ERR(kp_addr))
-		return false;
-
-	if (!kallsyms_lookup_size_offset((unsigned long)kp_addr, NULL, &offset) ||
-						!arch_kprobe_on_func_entry(offset))
-		return false;
-
-	return true;
-}
-
 int register_kretprobe(struct kretprobe *rp)
 {
 	int ret = 0;
-- 
2.20.1