linux-kernel - [PATCH -tip v7 02/13] kprobes: treewide: Replace arch_deref_entry_point() with dereference_symbol

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Message-Id: <162209756220.436794.2708979752685240734.stgit@devnote2>
Date:   Thu, 27 May 2021 15:39:22 +0900
From:   Masami Hiramatsu <mhiramat@...nel.org>
To:     Steven Rostedt <rostedt@...dmis.org>,
        Ingo Molnar <mingo@...nel.org>
Cc:     X86 ML <x86@...nel.org>, Masami Hiramatsu <mhiramat@...nel.org>,
        Daniel Xu <dxu@...uu.xyz>, linux-kernel@...r.kernel.org,
        bpf@...r.kernel.org, kuba@...nel.org, mingo@...hat.com,
        ast@...nel.org, tglx@...utronix.de, kernel-team@...com, yhs@...com,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        linux-ia64@...r.kernel.org,
        Abhishek Sagar <sagar.abhishek@...il.com>,
        Andrii Nakryiko <andrii.nakryiko@...il.com>
Subject: [PATCH -tip v7 02/13] kprobes: treewide: Replace arch_deref_entry_point() with dereference_symbol_descriptor()

Replace arch_deref_entry_point() with dereference_symbol_descriptor()
because those are doing same thing.

Signed-off-by: Masami Hiramatsu <mhiramat@...nel.org>
Tested-by: Andrii Nakryik <andrii@...nel.org>
---
 Changes in v6:
  - Use dereference_symbol_descriptor() so that it can handle address in
    modules correctly.
---
 arch/ia64/kernel/kprobes.c    |    5 -----
 arch/powerpc/kernel/kprobes.c |   11 -----------
 include/linux/kprobes.h       |    1 -
 kernel/kprobes.c              |    7 +------
 lib/error-inject.c            |    3 ++-
 5 files changed, 3 insertions(+), 24 deletions(-)

diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
index ca4b4fa45aef..eaf3c734719b 100644
--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -907,11 +907,6 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
 	return ret;
 }
 
-unsigned long arch_deref_entry_point(void *entry)
-{
-	return ((struct fnptr *)entry)->ip;
-}
-
 static struct kprobe trampoline_p = {
 	.pre_handler = trampoline_probe_handler
 };
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 01ab2163659e..eb0460949e1b 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -539,17 +539,6 @@ int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
 }
 NOKPROBE_SYMBOL(kprobe_fault_handler);
 
-unsigned long arch_deref_entry_point(void *entry)
-{
-#ifdef PPC64_ELF_ABI_v1
-	if (!kernel_text_address((unsigned long)entry))
-		return ppc_global_function_entry(entry);
-	else
-#endif
-		return (unsigned long)entry;
-}
-NOKPROBE_SYMBOL(arch_deref_entry_point);
-
 static struct kprobe trampoline_p = {
 	.addr = (kprobe_opcode_t *) &kretprobe_trampoline,
 	.pre_handler = trampoline_probe_handler
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index 1883a4a9f16a..d65c041b5c22 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -390,7 +390,6 @@ int register_kprobe(struct kprobe *p);
 void unregister_kprobe(struct kprobe *p);
 int register_kprobes(struct kprobe **kps, int num);
 void unregister_kprobes(struct kprobe **kps, int num);
-unsigned long arch_deref_entry_point(void *);
 
 int register_kretprobe(struct kretprobe *rp);
 void unregister_kretprobe(struct kretprobe *rp);
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 745f08fdd7a6..b2bb572173d4 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1856,11 +1856,6 @@ static struct notifier_block kprobe_exceptions_nb = {
 	.priority = 0x7fffffff /* we need to be notified first */
 };
 
-unsigned long __weak arch_deref_entry_point(void *entry)
-{
-	return (unsigned long)entry;
-}
-
 #ifdef CONFIG_KRETPROBES
 
 unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
@@ -2324,7 +2319,7 @@ static int __init populate_kprobe_blacklist(unsigned long *start,
 	int ret;
 
 	for (iter = start; iter < end; iter++) {
-		entry = arch_deref_entry_point((void *)*iter);
+		entry = (unsigned long)dereference_symbol_descriptor((void *)*iter);
 		ret = kprobe_add_ksym_blacklist(entry);
 		if (ret == -EINVAL)
 			continue;
diff --git a/lib/error-inject.c b/lib/error-inject.c
index c73651b15b76..2ff5ef689d72 100644
--- a/lib/error-inject.c
+++ b/lib/error-inject.c
@@ -8,6 +8,7 @@
 #include <linux/mutex.h>
 #include <linux/list.h>
 #include <linux/slab.h>
+#include <asm/sections.h>
 
 /* Whitelist of symbols that can be overridden for error injection. */
 static LIST_HEAD(error_injection_list);
@@ -64,7 +65,7 @@ static void populate_error_injection_list(struct error_injection_entry *start,
 
 	mutex_lock(&ei_mutex);
 	for (iter = start; iter < end; iter++) {
-		entry = arch_deref_entry_point((void *)iter->addr);
+		entry = (unsigned long)dereference_symbol_descriptor((void *)iter->addr);
 
 		if (!kernel_text_address(entry) ||
 		    !kallsyms_lookup_size_offset(entry, &size, &offset)) {