kprobes: treewide: Cleanup the error messages for kprobes

This clean up the error/notification messages in kprobes related code.
Basically this defines 'pr_fmt()' macros for each files and update
the messages which describes

 - what happened,
 - what is the kernel going to do or not do,
 - is the kernel fine,
 - what can the user do about it.

Also, if the message is not needed (e.g. the function returns unique
error code, or other error message is already shown.) remove it,
and replace the message with WARN_*() macros if suitable.

Link: https://lkml.kernel.org/r/163163036568.489837.14085396178727185469.stgit@devnote2

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

6 files changed, 25 insertions, 20 deletions

diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c
index 27e0af78e88b..a59e38de4a03 100644
--- a/arch/arm/probes/kprobes/core.c
+++ b/arch/arm/probes/kprobes/core.c
@@ -11,6 +11,8 @@
  * Copyright (C) 2007 Marvell Ltd.
  */
 
+#define pr_fmt(fmt) "kprobes: " fmt
+
 #include <linux/kernel.h>
 #include <linux/kprobes.h>
 #include <linux/module.h>
@@ -278,7 +280,7 @@ void __kprobes kprobe_handler(struct pt_regs *regs)
 				break;
 			case KPROBE_REENTER:
 				/* A nested probe was hit in FIQ, it is a BUG */
-				pr_warn("Unrecoverable kprobe detected.\n");
+				pr_warn("Failed to recover from reentered kprobes.\n");
 				dump_kprobe(p);
 				fallthrough;
 			default:
diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
index 6dbcc89f6662..ce429cbacd35 100644
--- a/arch/arm64/kernel/probes/kprobes.c
+++ b/arch/arm64/kernel/probes/kprobes.c
@@ -7,6 +7,9 @@
  * Copyright (C) 2013 Linaro Limited.
  * Author: Sandeepa Prabhu <sandeepa.prabhu@linaro.org>
  */
+
+#define pr_fmt(fmt) "kprobes: " fmt
+
 #include <linux/extable.h>
 #include <linux/kasan.h>
 #include <linux/kernel.h>
@@ -218,7 +221,7 @@ static int __kprobes reenter_kprobe(struct kprobe *p,
 		break;
 	case KPROBE_HIT_SS:
 	case KPROBE_REENTER:
-		pr_warn("Unrecoverable kprobe detected.\n");
+		pr_warn("Failed to recover from reentered kprobes.\n");
 		dump_kprobe(p);
 		BUG();
 		break;
diff --git a/arch/csky/kernel/probes/kprobes.c b/arch/csky/kernel/probes/kprobes.c
index 8fffa34d4e1c..632407bf45d5 100644
--- a/arch/csky/kernel/probes/kprobes.c
+++ b/arch/csky/kernel/probes/kprobes.c
@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0+
 
+#define pr_fmt(fmt) "kprobes: " fmt
+
 #include <linux/kprobes.h>
 #include <linux/extable.h>
 #include <linux/slab.h>
@@ -77,10 +79,8 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
 {
 	unsigned long probe_addr = (unsigned long)p->addr;
 
-	if (probe_addr & 0x1) {
-		pr_warn("Address not aligned.\n");
-		return -EINVAL;
-	}
+	if (probe_addr & 0x1)
+		return -EILSEQ;
 
 	/* copy instruction */
 	p->opcode = le32_to_cpu(*p->addr);
@@ -225,7 +225,7 @@ static int __kprobes reenter_kprobe(struct kprobe *p,
 		break;
 	case KPROBE_HIT_SS:
 	case KPROBE_REENTER:
-		pr_warn("Unrecoverable kprobe detected.\n");
+		pr_warn("Failed to recover from reentered kprobes.\n");
 		dump_kprobe(p);
 		BUG();
 		break;
diff --git a/arch/mips/kernel/kprobes.c b/arch/mips/kernel/kprobes.c
index 75bff0f77319..b0934a0d7aed 100644
--- a/arch/mips/kernel/kprobes.c
+++ b/arch/mips/kernel/kprobes.c
@@ -11,6 +11,8 @@
  *   Copyright (C) IBM Corporation, 2002, 2004
  */
 
+#define pr_fmt(fmt) "kprobes: " fmt
+
 #include <linux/kprobes.h>
 #include <linux/preempt.h>
 #include <linux/uaccess.h>
@@ -80,8 +82,7 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
 	insn = p->addr[0];
 
 	if (insn_has_ll_or_sc(insn)) {
-		pr_notice("Kprobes for ll and sc instructions are not"
-			  "supported\n");
+		pr_notice("Kprobes for ll and sc instructions are not supported\n");
 		ret = -EINVAL;
 		goto out;
 	}
@@ -219,7 +220,7 @@ static int evaluate_branch_instruction(struct kprobe *p, struct pt_regs *regs,
 	return 0;
 
 unaligned:
-	pr_notice("%s: unaligned epc - sending SIGBUS.\n", current->comm);
+	pr_notice("Failed to emulate branch instruction because of unaligned epc - sending SIGBUS to %s.\n", current->comm);
 	force_sig(SIGBUS);
 	return -EFAULT;
 
@@ -238,10 +239,8 @@ static void prepare_singlestep(struct kprobe *p, struct pt_regs *regs,
 		regs->cp0_epc = (unsigned long)p->addr;
 	else if (insn_has_delayslot(p->opcode)) {
 		ret = evaluate_branch_instruction(p, regs, kcb);
-		if (ret < 0) {
-			pr_notice("Kprobes: Error in evaluating branch\n");
+		if (ret < 0)
 			return;
-		}
 	}
 	regs->cp0_epc = (unsigned long)&p->ainsn.insn[0];
 }
diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c
index 00088dc6da4b..cab6f874358e 100644
--- a/arch/riscv/kernel/probes/kprobes.c
+++ b/arch/riscv/kernel/probes/kprobes.c
@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0+
 
+#define pr_fmt(fmt) "kprobes: " fmt
+
 #include <linux/kprobes.h>
 #include <linux/extable.h>
 #include <linux/slab.h>
@@ -50,11 +52,8 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
 {
 	unsigned long probe_addr = (unsigned long)p->addr;
 
-	if (probe_addr & 0x1) {
-		pr_warn("Address not aligned.\n");
-
-		return -EINVAL;
-	}
+	if (probe_addr & 0x1)
+		return -EILSEQ;
 
 	/* copy instruction */
 	p->opcode = *p->addr;
@@ -191,7 +190,7 @@ static int __kprobes reenter_kprobe(struct kprobe *p,
 		break;
 	case KPROBE_HIT_SS:
 	case KPROBE_REENTER:
-		pr_warn("Unrecoverable kprobe detected.\n");
+		pr_warn("Failed to recover from reentered kprobes.\n");
 		dump_kprobe(p);
 		BUG();
 		break;
diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index 52d056a5f89f..952d44b0610b 100644
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -7,6 +7,8 @@
  * s390 port, used ppc64 as template. Mike Grundy <grundym@us.ibm.com>
  */
 
+#define pr_fmt(fmt) "kprobes: " fmt
+
 #include <linux/moduleloader.h>
 #include <linux/kprobes.h>
 #include <linux/ptrace.h>
@@ -259,7 +261,7 @@ static void kprobe_reenter_check(struct kprobe_ctlblk *kcb, struct kprobe *p)
 		 * is a BUG. The code path resides in the .kprobes.text
 		 * section and is executed with interrupts disabled.
 		 */
-		pr_err("Invalid kprobe detected.\n");
+		pr_err("Failed to recover from reentered kprobes.\n");
 		dump_kprobe(p);
 		BUG();
 	}