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Subject[PATCH v5 6/8] kernel/jump_label: abstract jump_entry member accessors
Date
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@linaro.org>
---
arch/arm/include/asm/jump_label.h | 27 ++++++++++++++
arch/arm64/include/asm/jump_label.h | 27 ++++++++++++++
arch/mips/include/asm/jump_label.h | 27 ++++++++++++++
arch/powerpc/include/asm/jump_label.h | 27 ++++++++++++++
arch/s390/include/asm/jump_label.h | 20 +++++++++++
arch/sparc/include/asm/jump_label.h | 27 ++++++++++++++
arch/tile/include/asm/jump_label.h | 27 ++++++++++++++
arch/x86/include/asm/jump_label.h | 27 ++++++++++++++
kernel/jump_label.c | 38 +++++++++-----------
9 files changed, 225 insertions(+), 22 deletions(-)

diff --git a/arch/arm/include/asm/jump_label.h b/arch/arm/include/asm/jump_label.h
index e12d7d096fc0..7b05b404063a 100644
--- a/arch/arm/include/asm/jump_label.h
+++ b/arch/arm/include/asm/jump_label.h
@@ -45,5 +45,32 @@ struct jump_entry {
jump_label_t key;
};

+static inline jump_label_t jump_entry_code(const struct jump_entry *entry)
+{
+ return entry->code;
+}
+
+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;
+}
+
+#define jump_label_swap NULL
+
#endif /* __ASSEMBLY__ */
#endif
diff --git a/arch/arm64/include/asm/jump_label.h b/arch/arm64/include/asm/jump_label.h
index 1b5e0e843c3a..9d6e46355c89 100644
--- a/arch/arm64/include/asm/jump_label.h
+++ b/arch/arm64/include/asm/jump_label.h
@@ -62,5 +62,32 @@ struct jump_entry {
jump_label_t key;
};

+static inline jump_label_t jump_entry_code(const struct jump_entry *entry)
+{
+ return entry->code;
+}
+
+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;
+}
+
+#define jump_label_swap NULL
+
#endif /* __ASSEMBLY__ */
#endif /* __ASM_JUMP_LABEL_H */
diff --git a/arch/mips/include/asm/jump_label.h b/arch/mips/include/asm/jump_label.h
index e77672539e8e..70df9293dc49 100644
--- a/arch/mips/include/asm/jump_label.h
+++ b/arch/mips/include/asm/jump_label.h
@@ -66,5 +66,32 @@ struct jump_entry {
jump_label_t key;
};

+static inline jump_label_t jump_entry_code(const struct jump_entry *entry)
+{
+ return entry->code;
+}
+
+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;
+}
+
+#define jump_label_swap NULL
+
#endif /* __ASSEMBLY__ */
#endif /* _ASM_MIPS_JUMP_LABEL_H */
diff --git a/arch/powerpc/include/asm/jump_label.h b/arch/powerpc/include/asm/jump_label.h
index 9a287e0ac8b1..412b2699c9f6 100644
--- a/arch/powerpc/include/asm/jump_label.h
+++ b/arch/powerpc/include/asm/jump_label.h
@@ -59,6 +59,33 @@ struct jump_entry {
jump_label_t key;
};

+static inline jump_label_t jump_entry_code(const struct jump_entry *entry)
+{
+ return entry->code;
+}
+
+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;
+}
+
+#define jump_label_swap NULL
+
#else
#define ARCH_STATIC_BRANCH(LABEL, KEY) \
1098: nop; \
diff --git a/arch/s390/include/asm/jump_label.h b/arch/s390/include/asm/jump_label.h
index 40f651292aa7..3d4a08e9514b 100644
--- a/arch/s390/include/asm/jump_label.h
+++ b/arch/s390/include/asm/jump_label.h
@@ -50,5 +50,25 @@ struct jump_entry {
jump_label_t key;
};

+static inline jump_label_t jump_entry_code(const struct jump_entry *entry)
+{
+ return entry->code;
+}
+
+static inline jump_label_t jump_entry_key(const struct jump_entry *entry)
+{
+ return entry->key;
+}
+
+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 /* __ASSEMBLY__ */
#endif
diff --git a/arch/sparc/include/asm/jump_label.h b/arch/sparc/include/asm/jump_label.h
index 94eb529dcb77..18e893687f7c 100644
--- a/arch/sparc/include/asm/jump_label.h
+++ b/arch/sparc/include/asm/jump_label.h
@@ -48,5 +48,32 @@ struct jump_entry {
jump_label_t key;
};

+static inline jump_label_t jump_entry_code(const struct jump_entry *entry)
+{
+ return entry->code;
+}
+
+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;
+}
+
+#define jump_label_swap NULL
+
#endif /* __ASSEMBLY__ */
#endif
diff --git a/arch/tile/include/asm/jump_label.h b/arch/tile/include/asm/jump_label.h
index cde7573f397b..86acaa6ff33d 100644
--- a/arch/tile/include/asm/jump_label.h
+++ b/arch/tile/include/asm/jump_label.h
@@ -55,4 +55,31 @@ struct jump_entry {
jump_label_t key;
};

+static inline jump_label_t jump_entry_code(const struct jump_entry *entry)
+{
+ return entry->code;
+}
+
+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;
+}
+
+#define jump_label_swap NULL
+
#endif /* _ASM_TILE_JUMP_LABEL_H */
diff --git a/arch/x86/include/asm/jump_label.h b/arch/x86/include/asm/jump_label.h
index 8c0de4282659..009ff2699d07 100644
--- a/arch/x86/include/asm/jump_label.h
+++ b/arch/x86/include/asm/jump_label.h
@@ -74,6 +74,33 @@ struct jump_entry {
jump_label_t key;
};

+static inline jump_label_t jump_entry_code(const struct jump_entry *entry)
+{
+ return entry->code;
+}
+
+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;
+}
+
+#define jump_label_swap NULL
+
#else /* __ASSEMBLY__ */

.macro STATIC_JUMP_IF_TRUE target, key, def
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index 8594d24e4adc..baed094ab8d1 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -37,10 +37,12 @@ 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;
@@ -53,7 +55,8 @@ jump_label_sort_entries(struct jump_entry *start, struct jump_entry *stop)

size = (((unsigned long)stop - (unsigned long)start)
/ sizeof(struct jump_entry));
- sort(start, size, sizeof(struct jump_entry), jump_label_cmp, NULL);
+ sort(start, size, sizeof(struct jump_entry), jump_label_cmp,
+ jump_label_swap);
}

static void jump_label_update(struct static_key *key);
@@ -254,8 +257,8 @@ 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;
@@ -314,16 +317,6 @@ 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
@@ -348,7 +341,7 @@ 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;
@@ -364,7 +357,8 @@ static void __jump_label_update(struct static_key *key,
* kernel_text_address() verifies we are not in core kernel
* init code, see jump_label_invalidate_module_init().
*/
- if (entry->code && kernel_text_address(entry->code))
+ if (jump_entry_is_module_init(entry) &&
+ kernel_text_address(jump_entry_code(entry)))
arch_jump_label_transform(entry, jump_label_type(entry));
}
}
@@ -417,7 +411,7 @@ 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;
@@ -541,7 +535,7 @@ 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;
}
@@ -591,7 +585,7 @@ 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 */
@@ -634,8 +628,8 @@ 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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