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Message-Id: <20180627160604.8154-2-ard.biesheuvel@linaro.org>
Date: Wed, 27 Jun 2018 18:06:00 +0200
From: Ard Biesheuvel <ard.biesheuvel@...aro.org>
To: linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
x86@...nel.org
Cc: Ard Biesheuvel <ard.biesheuvel@...aro.org>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will.deacon@....com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Arnd Bergmann <arnd@...db.de>,
Steven Rostedt <rostedt@...dmis.org>,
Peter Zijlstra <peterz@...radead.org>
Subject: [PATCH 1/5] kernel/jump_label: abstract jump_entry member accessors
In preparation of allowing architectures to use relative references
in jump_label entries [which can dramatically reduce the memory
footprint], introduce abstractions for references to the 'code' and
'key' members of struct jump_entry.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>
---
include/linux/jump_label.h | 36 ++++++++++++++++++++
kernel/jump_label.c | 36 ++++++++------------
2 files changed, 50 insertions(+), 22 deletions(-)
diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index b46b541c67c4..86ec0652d3b1 100644
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -119,6 +119,42 @@ struct static_key {
#ifdef HAVE_JUMP_LABEL
#include <asm/jump_label.h>
+
+#ifndef __ASSEMBLY__
+
+struct jump_entry; /* defined by the architecture */
+
+static inline unsigned long jump_entry_code(const struct jump_entry *entry)
+{
+ return entry->code;
+}
+
+static inline unsigned long jump_entry_target(const struct jump_entry *entry)
+{
+ return entry->target;
+}
+
+static inline struct static_key *jump_entry_key(const struct jump_entry *entry)
+{
+ return (struct static_key *)((unsigned long)entry->key & ~1UL);
+}
+
+static inline bool jump_entry_is_branch(const struct jump_entry *entry)
+{
+ return (unsigned long)entry->key & 1UL;
+}
+
+static inline bool jump_entry_is_module_init(const struct jump_entry *entry)
+{
+ return entry->code == 0;
+}
+
+static inline void jump_entry_set_module_init(struct jump_entry *entry)
+{
+ entry->code = 0;
+}
+
+#endif
#endif
#ifndef __ASSEMBLY__
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index 01ebdf1f9f40..c3524c9b3004 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -38,10 +38,12 @@ static int jump_label_cmp(const void *a, const void *b)
const struct jump_entry *jea = a;
const struct jump_entry *jeb = b;
- if (jea->key < jeb->key)
+ if ((unsigned long)jump_entry_key(jea) <
+ (unsigned long)jump_entry_key(jeb))
return -1;
- if (jea->key > jeb->key)
+ if ((unsigned long)jump_entry_key(jea) >
+ (unsigned long)jump_entry_key(jeb))
return 1;
return 0;
@@ -261,8 +263,8 @@ EXPORT_SYMBOL_GPL(jump_label_rate_limit);
static int addr_conflict(struct jump_entry *entry, void *start, void *end)
{
- if (entry->code <= (unsigned long)end &&
- entry->code + JUMP_LABEL_NOP_SIZE > (unsigned long)start)
+ if (jump_entry_code(entry) <= (unsigned long)end &&
+ jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE > (unsigned long)start)
return 1;
return 0;
@@ -321,16 +323,6 @@ static inline void static_key_set_linked(struct static_key *key)
key->type |= JUMP_TYPE_LINKED;
}
-static inline struct static_key *jump_entry_key(struct jump_entry *entry)
-{
- return (struct static_key *)((unsigned long)entry->key & ~1UL);
-}
-
-static bool jump_entry_branch(struct jump_entry *entry)
-{
- return (unsigned long)entry->key & 1UL;
-}
-
/***
* A 'struct static_key' uses a union such that it either points directly
* to a table of 'struct jump_entry' or to a linked list of modules which in
@@ -355,7 +347,7 @@ static enum jump_label_type jump_label_type(struct jump_entry *entry)
{
struct static_key *key = jump_entry_key(entry);
bool enabled = static_key_enabled(key);
- bool branch = jump_entry_branch(entry);
+ bool branch = jump_entry_is_branch(entry);
/* See the comment in linux/jump_label.h */
return enabled ^ branch;
@@ -370,8 +362,8 @@ static void __jump_label_update(struct static_key *key,
* An entry->code of 0 indicates an entry which has been
* disabled because it was in an init text area.
*/
- if (entry->code) {
- if (kernel_text_address(entry->code))
+ if (!jump_entry_is_module_init(entry)) {
+ if (kernel_text_address(jump_entry_code(entry)))
arch_jump_label_transform(entry, jump_label_type(entry));
else
WARN_ONCE(1, "can't patch jump_label at %pS",
@@ -441,7 +433,7 @@ static enum jump_label_type jump_label_init_type(struct jump_entry *entry)
{
struct static_key *key = jump_entry_key(entry);
bool type = static_key_type(key);
- bool branch = jump_entry_branch(entry);
+ bool branch = jump_entry_is_branch(entry);
/* See the comment in linux/jump_label.h */
return type ^ branch;
@@ -565,7 +557,7 @@ static int jump_label_add_module(struct module *mod)
continue;
key = iterk;
- if (within_module(iter->key, mod)) {
+ if (within_module((unsigned long)key, mod)) {
static_key_set_entries(key, iter);
continue;
}
@@ -615,7 +607,7 @@ static void jump_label_del_module(struct module *mod)
key = jump_entry_key(iter);
- if (within_module(iter->key, mod))
+ if (within_module((unsigned long)key, mod))
continue;
/* No memory during module load */
@@ -659,8 +651,8 @@ static void jump_label_invalidate_module_init(struct module *mod)
struct jump_entry *iter;
for (iter = iter_start; iter < iter_stop; iter++) {
- if (within_module_init(iter->code, mod))
- iter->code = 0;
+ if (within_module_init(jump_entry_code(iter), mod))
+ jump_entry_set_module_init(iter);
}
}
--
2.11.0
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