Re: [PATCH] jump label: constify lookup functions

From: Sasha Levin
Date: Fri Mar 14 2014 - 15:40:46 EST

ping?

On 02/12/2014 08:56 AM, Sasha Levin wrote:
ping?

On 01/27/2014 02:27 PM, Sasha Levin wrote:
Modify the parameters of all the lookup and the bookkeeping functions which
should be const to const.

For example, jump_label_text_reserved() doesn't modify the memory it works on,
it just checks whether there are any jump labels there.

Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---
arch/arm/include/asm/jump_label.h | 2 +-
arch/arm/kernel/jump_label.c | 6 ++---
arch/arm64/include/asm/jump_label.h | 2 +-
arch/arm64/kernel/jump_label.c | 6 ++---
arch/mips/include/asm/jump_label.h | 2 +-
arch/mips/kernel/jump_label.c | 2 +-
arch/powerpc/include/asm/jump_label.h | 2 +-
arch/powerpc/kernel/jump_label.c | 2 +-
arch/s390/include/asm/jump_label.h | 2 +-
arch/s390/kernel/jump_label.c | 12 ++++-----
arch/sparc/include/asm/jump_label.h | 2 +-
arch/sparc/kernel/jump_label.c | 2 +-
arch/x86/include/asm/jump_label.h | 2 +-
arch/x86/include/asm/spinlock.h | 2 +-
arch/x86/kernel/jump_label.c | 6 ++---
include/linux/jump_label.h | 27 ++++++++++----------
kernel/jump_label.c | 46 ++++++++++++++++++-----------------
17 files changed, 64 insertions(+), 61 deletions(-)

diff --git a/arch/arm/include/asm/jump_label.h b/arch/arm/include/asm/jump_label.h
index 863c892..c8a5e9f 100644
--- a/arch/arm/include/asm/jump_label.h
+++ b/arch/arm/include/asm/jump_label.h
@@ -14,7 +14,7 @@
#define JUMP_LABEL_NOP "nop"
#endif

-static __always_inline bool arch_static_branch(struct static_key *key)
+static __always_inline bool arch_static_branch(const struct static_key *key)
{
asm_volatile_goto("1:\n\t"
JUMP_LABEL_NOP "\n\t"
diff --git a/arch/arm/kernel/jump_label.c b/arch/arm/kernel/jump_label.c
index 4ce4f78..9686fce 100644
--- a/arch/arm/kernel/jump_label.c
+++ b/arch/arm/kernel/jump_label.c
@@ -6,7 +6,7 @@

#ifdef HAVE_JUMP_LABEL

-static void __arch_jump_label_transform(struct jump_entry *entry,
+static void __arch_jump_label_transform(const struct jump_entry *entry,
enum jump_label_type type,
bool is_static)
{
@@ -24,13 +24,13 @@ static void __arch_jump_label_transform(struct jump_entry *entry,
patch_text(addr, insn);
}

-void arch_jump_label_transform(struct jump_entry *entry,
+void arch_jump_label_transform(const struct jump_entry *entry,
enum jump_label_type type)
{
__arch_jump_label_transform(entry, type, false);
}

-void arch_jump_label_transform_static(struct jump_entry *entry,
+void arch_jump_label_transform_static(const struct jump_entry *entry,
enum jump_label_type type)
{
__arch_jump_label_transform(entry, type, true);
diff --git a/arch/arm64/include/asm/jump_label.h b/arch/arm64/include/asm/jump_label.h
index 076a1c7..93ca8b3 100644
--- a/arch/arm64/include/asm/jump_label.h
+++ b/arch/arm64/include/asm/jump_label.h
@@ -25,7 +25,7 @@

#define JUMP_LABEL_NOP_SIZE AARCH64_INSN_SIZE

-static __always_inline bool arch_static_branch(struct static_key *key)
+static __always_inline bool arch_static_branch(const struct static_key *key)
{
asm goto("1: nop\n\t"
".pushsection __jump_table, \"aw\"\n\t"
diff --git a/arch/arm64/kernel/jump_label.c b/arch/arm64/kernel/jump_label.c
index 263a166..c30e4ba 100644
--- a/arch/arm64/kernel/jump_label.c
+++ b/arch/arm64/kernel/jump_label.c
@@ -22,7 +22,7 @@

#ifdef HAVE_JUMP_LABEL

-static void __arch_jump_label_transform(struct jump_entry *entry,
+static void __arch_jump_label_transform(const struct jump_entry *entry,
enum jump_label_type type,
bool is_static)
{
@@ -43,13 +43,13 @@ static void __arch_jump_label_transform(struct jump_entry *entry,
aarch64_insn_patch_text(&addr, &insn, 1);
}

-void arch_jump_label_transform(struct jump_entry *entry,
+void arch_jump_label_transform(const struct jump_entry *entry,
enum jump_label_type type)
{
__arch_jump_label_transform(entry, type, false);
}

-void arch_jump_label_transform_static(struct jump_entry *entry,
+void arch_jump_label_transform_static(const struct jump_entry *entry,
enum jump_label_type type)
{
__arch_jump_label_transform(entry, type, true);
diff --git a/arch/mips/include/asm/jump_label.h b/arch/mips/include/asm/jump_label.h
index e194f95..0ac7892 100644
--- a/arch/mips/include/asm/jump_label.h
+++ b/arch/mips/include/asm/jump_label.h
@@ -20,7 +20,7 @@
#define WORD_INSN ".word"
#endif

-static __always_inline bool arch_static_branch(struct static_key *key)
+static __always_inline bool arch_static_branch(const struct static_key *key)
{
asm_volatile_goto("1:\tnop\n\t"
"nop\n\t"
diff --git a/arch/mips/kernel/jump_label.c b/arch/mips/kernel/jump_label.c
index 6001610..bfba488 100644
--- a/arch/mips/kernel/jump_label.c
+++ b/arch/mips/kernel/jump_label.c
@@ -20,7 +20,7 @@

#define J_RANGE_MASK ((1ul << 28) - 1)

-void arch_jump_label_transform(struct jump_entry *e,
+void arch_jump_label_transform(const struct jump_entry *e,
enum jump_label_type type)
{
union mips_instruction insn;
diff --git a/arch/powerpc/include/asm/jump_label.h b/arch/powerpc/include/asm/jump_label.h
index f016bb6..93eb7c5 100644
--- a/arch/powerpc/include/asm/jump_label.h
+++ b/arch/powerpc/include/asm/jump_label.h
@@ -17,7 +17,7 @@
#define JUMP_ENTRY_TYPE stringify_in_c(FTR_ENTRY_LONG)
#define JUMP_LABEL_NOP_SIZE 4

-static __always_inline bool arch_static_branch(struct static_key *key)
+static __always_inline bool arch_static_branch(const struct static_key *key)
{
asm_volatile_goto("1:\n\t"
"nop\n\t"
diff --git a/arch/powerpc/kernel/jump_label.c b/arch/powerpc/kernel/jump_label.c
index a1ed8a8..f9626ec 100644
--- a/arch/powerpc/kernel/jump_label.c
+++ b/arch/powerpc/kernel/jump_label.c
@@ -12,7 +12,7 @@
#include <asm/code-patching.h>

#ifdef HAVE_JUMP_LABEL
-void arch_jump_label_transform(struct jump_entry *entry,
+void arch_jump_label_transform(const struct jump_entry *entry,
enum jump_label_type type)
{
u32 *addr = (u32 *)(unsigned long)entry->code;
diff --git a/arch/s390/include/asm/jump_label.h b/arch/s390/include/asm/jump_label.h
index 346b1c8..9ee8e1b 100644
--- a/arch/s390/include/asm/jump_label.h
+++ b/arch/s390/include/asm/jump_label.h
@@ -13,7 +13,7 @@
#define ASM_ALIGN ".balign 4"
#endif

-static __always_inline bool arch_static_branch(struct static_key *key)
+static __always_inline bool arch_static_branch(const struct static_key *key)
{
asm_volatile_goto("0: brcl 0,0\n"
".pushsection __jump_table, \"aw\"\n"
diff --git a/arch/s390/kernel/jump_label.c b/arch/s390/kernel/jump_label.c
index b987ab2..15a7c60 100644
--- a/arch/s390/kernel/jump_label.c
+++ b/arch/s390/kernel/jump_label.c
@@ -18,11 +18,11 @@ struct insn {
} __packed;

struct insn_args {
- struct jump_entry *entry;
+ const const struct jump_entry *entry;
enum jump_label_type type;
};

-static void __jump_label_transform(struct jump_entry *entry,
+static void __jump_label_transform(const struct jump_entry *entry,
enum jump_label_type type)
{
struct insn insn;
@@ -42,15 +42,15 @@ static void __jump_label_transform(struct jump_entry *entry,
WARN_ON_ONCE(rc < 0);
}

-static int __sm_arch_jump_label_transform(void *data)
+static int __sm_arch_jump_label_transform(const void *data)
{
- struct insn_args *args = data;
+ const struct insn_args *args = data;

__jump_label_transform(args->entry, args->type);
return 0;
}

-void arch_jump_label_transform(struct jump_entry *entry,
+void arch_jump_label_transform(const struct jump_entry *entry,
enum jump_label_type type)
{
struct insn_args args;
@@ -61,7 +61,7 @@ void arch_jump_label_transform(struct jump_entry *entry,
stop_machine(__sm_arch_jump_label_transform, &args, NULL);
}

-void arch_jump_label_transform_static(struct jump_entry *entry,
+void arch_jump_label_transform_static(const struct jump_entry *entry,
enum jump_label_type type)
{
__jump_label_transform(entry, type);
diff --git a/arch/sparc/include/asm/jump_label.h b/arch/sparc/include/asm/jump_label.h
index ec2e2e2..4f1f223 100644
--- a/arch/sparc/include/asm/jump_label.h
+++ b/arch/sparc/include/asm/jump_label.h
@@ -7,7 +7,7 @@

#define JUMP_LABEL_NOP_SIZE 4

-static __always_inline bool arch_static_branch(struct static_key *key)
+static __always_inline bool arch_static_branch(const struct static_key *key)
{
asm_volatile_goto("1:\n\t"
"nop\n\t"
diff --git a/arch/sparc/kernel/jump_label.c b/arch/sparc/kernel/jump_label.c
index 48565c1..231c10e 100644
--- a/arch/sparc/kernel/jump_label.c
+++ b/arch/sparc/kernel/jump_label.c
@@ -10,7 +10,7 @@

#ifdef HAVE_JUMP_LABEL

-void arch_jump_label_transform(struct jump_entry *entry,
+void arch_jump_label_transform(const struct jump_entry *entry,
enum jump_label_type type)
{
u32 val;
diff --git a/arch/x86/include/asm/jump_label.h b/arch/x86/include/asm/jump_label.h
index 6a2cefb..329ab91 100644
--- a/arch/x86/include/asm/jump_label.h
+++ b/arch/x86/include/asm/jump_label.h
@@ -16,7 +16,7 @@
# define STATIC_KEY_INIT_NOP GENERIC_NOP5_ATOMIC
#endif

-static __always_inline bool arch_static_branch(struct static_key *key)
+static __always_inline bool arch_static_branch(const struct static_key *key)
{
asm_volatile_goto("1:"
".byte " __stringify(STATIC_KEY_INIT_NOP) "\n\t"
diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h
index bf156de..5af9269 100644
--- a/arch/x86/include/asm/spinlock.h
+++ b/arch/x86/include/asm/spinlock.h
@@ -41,7 +41,7 @@
#define SPIN_THRESHOLD (1 << 15)

extern struct static_key paravirt_ticketlocks_enabled;
-static __always_inline bool static_key_false(struct static_key *key);
+static __always_inline bool static_key_false(const struct static_key *key);

#ifdef CONFIG_PARAVIRT_SPINLOCKS

diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c
index 26d5a55..fe1cc9d 100644
--- a/arch/x86/kernel/jump_label.c
+++ b/arch/x86/kernel/jump_label.c
@@ -36,7 +36,7 @@ static void bug_at(unsigned char *ip, int line)
BUG();
}

-static void __jump_label_transform(struct jump_entry *entry,
+static void __jump_label_transform(const struct jump_entry *entry,
enum jump_label_type type,
void *(*poker)(void *, const void *, size_t),
int init)
@@ -102,7 +102,7 @@ static void __jump_label_transform(struct jump_entry *entry,
(void *)entry->code + JUMP_LABEL_NOP_SIZE);
}

-void arch_jump_label_transform(struct jump_entry *entry,
+void arch_jump_label_transform(const struct jump_entry *entry,
enum jump_label_type type)
{
get_online_cpus();
@@ -118,7 +118,7 @@ static enum {
JL_STATE_UPDATE,
} jlstate __initdata_or_module = JL_STATE_START;

-__init_or_module void arch_jump_label_transform_static(struct jump_entry *entry,
+__init_or_module void arch_jump_label_transform_static(const struct jump_entry *entry,
enum jump_label_type type)
{
/*
diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index 5c1dfb2..2b2e358 100644
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -86,13 +86,14 @@ struct module;
#define JUMP_LABEL_TYPE_MASK 1UL

static
-inline struct jump_entry *jump_label_get_entries(struct static_key *key)
+inline const struct jump_entry *jump_label_get_entries(
+ const struct static_key *key)
{
return (struct jump_entry *)((unsigned long)key->entries
& ~JUMP_LABEL_TYPE_MASK);
}

-static inline bool jump_label_get_branch_default(struct static_key *key)
+static inline bool jump_label_get_branch_default(const struct static_key *key)
{
if (((unsigned long)key->entries & JUMP_LABEL_TYPE_MASK) ==
JUMP_LABEL_TYPE_TRUE_BRANCH)
@@ -100,12 +101,12 @@ static inline bool jump_label_get_branch_default(struct static_key *key)
return false;
}

-static __always_inline bool static_key_false(struct static_key *key)
+static __always_inline bool static_key_false(const struct static_key *key)
{
return arch_static_branch(key);
}

-static __always_inline bool static_key_true(struct static_key *key)
+static __always_inline bool static_key_true(const struct static_key *key)
{
return !static_key_false(key);
}
@@ -116,14 +117,14 @@ extern struct jump_entry __stop___jump_table[];
extern void jump_label_init(void);
extern void jump_label_lock(void);
extern void jump_label_unlock(void);
-extern void arch_jump_label_transform(struct jump_entry *entry,
+extern void arch_jump_label_transform(const struct jump_entry *entry,
enum jump_label_type type);
-extern void arch_jump_label_transform_static(struct jump_entry *entry,
+extern void arch_jump_label_transform_static(const struct jump_entry *entry,
enum jump_label_type type);
-extern int jump_label_text_reserved(void *start, void *end);
+extern int jump_label_text_reserved(const void *start, const void *end);
extern void static_key_slow_inc(struct static_key *key);
extern void static_key_slow_dec(struct static_key *key);
-extern void jump_label_apply_nops(struct module *mod);
+extern void jump_label_apply_nops(const struct module *mod);

#define STATIC_KEY_INIT_TRUE ((struct static_key) \
{ .enabled = ATOMIC_INIT(1), \
@@ -143,14 +144,14 @@ static __always_inline void jump_label_init(void)
static_key_initialized = true;
}

-static __always_inline bool static_key_false(struct static_key *key)
+static __always_inline bool static_key_false(const struct static_key *key)
{
if (unlikely(atomic_read(&key->enabled) > 0))
return true;
return false;
}

-static __always_inline bool static_key_true(struct static_key *key)
+static __always_inline bool static_key_true(const struct static_key *key)
{
if (likely(atomic_read(&key->enabled) > 0))
return true;
@@ -169,7 +170,7 @@ static inline void static_key_slow_dec(struct static_key *key)
atomic_dec(&key->enabled);
}

-static inline int jump_label_text_reserved(void *start, void *end)
+static inline int jump_label_text_reserved(const void *start, const void *end)
{
return 0;
}
@@ -177,7 +178,7 @@ static inline int jump_label_text_reserved(void *start, void *end)
static inline void jump_label_lock(void) {}
static inline void jump_label_unlock(void) {}

-static inline int jump_label_apply_nops(struct module *mod)
+static inline int jump_label_apply_nops(const struct module *mod)
{
return 0;
}
@@ -192,7 +193,7 @@ static inline int jump_label_apply_nops(struct module *mod)
#define STATIC_KEY_INIT STATIC_KEY_INIT_FALSE
#define jump_label_enabled static_key_enabled

-static inline bool static_key_enabled(struct static_key *key)
+static inline bool static_key_enabled(const struct static_key *key)
{
return (atomic_read(&key->enabled) > 0);
}
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index 9019f15..6879f48 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -54,7 +54,7 @@ jump_label_sort_entries(struct jump_entry *start, struct jump_entry *stop)
sort(start, size, sizeof(struct jump_entry), jump_label_cmp, NULL);
}

-static void jump_label_update(struct static_key *key, int enable);
+static void jump_label_update(const struct static_key *key, int enable);

void static_key_slow_inc(struct static_key *key)
{
@@ -125,7 +125,8 @@ void jump_label_rate_limit(struct static_key_deferred *key,
}
EXPORT_SYMBOL_GPL(jump_label_rate_limit);

-static int addr_conflict(struct jump_entry *entry, void *start, void *end)
+static int addr_conflict(const struct jump_entry *entry, const void *start,
+ const void *end)
{
if (entry->code <= (unsigned long)end &&
entry->code + JUMP_LABEL_NOP_SIZE > (unsigned long)start)
@@ -134,10 +135,11 @@ static int addr_conflict(struct jump_entry *entry, void *start, void *end)
return 0;
}

-static int __jump_label_text_reserved(struct jump_entry *iter_start,
- struct jump_entry *iter_stop, void *start, void *end)
+static int __jump_label_text_reserved(const struct jump_entry *iter_start,
+ const struct jump_entry *iter_stop, const void *start,
+ const void *end)
{
- struct jump_entry *iter;
+ const struct jump_entry *iter;

iter = iter_start;
while (iter < iter_stop) {
@@ -155,15 +157,15 @@ static int __jump_label_text_reserved(struct jump_entry *iter_start,
* running code can override this to make the non-live update case
* cheaper.
*/
-void __weak __init_or_module arch_jump_label_transform_static(struct jump_entry *entry,
- enum jump_label_type type)
+void __weak __init_or_module arch_jump_label_transform_static(
+ const struct jump_entry *entry, enum jump_label_type type)
{
arch_jump_label_transform(entry, type);
}

-static void __jump_label_update(struct static_key *key,
- struct jump_entry *entry,
- struct jump_entry *stop, int enable)
+static void __jump_label_update(const struct static_key *key,
+ const struct jump_entry *entry,
+ const struct jump_entry *stop, int enable)
{
for (; (entry < stop) &&
(entry->key == (jump_label_t)(unsigned long)key);
@@ -178,7 +180,7 @@ static void __jump_label_update(struct static_key *key,
}
}

-static enum jump_label_type jump_label_type(struct static_key *key)
+static enum jump_label_type jump_label_type(const struct static_key *key)
{
bool true_branch = jump_label_get_branch_default(key);
bool state = static_key_enabled(key);
@@ -228,9 +230,9 @@ struct static_key_mod {
struct module *mod;
};

-static int __jump_label_mod_text_reserved(void *start, void *end)
+static int __jump_label_mod_text_reserved(const void *start, const void *end)
{
- struct module *mod;
+ const struct module *mod;

mod = __module_text_address((unsigned long)start);
if (!mod)
@@ -243,12 +245,12 @@ static int __jump_label_mod_text_reserved(void *start, void *end)
start, end);
}

-static void __jump_label_mod_update(struct static_key *key, int enable)
+static void __jump_label_mod_update(const struct static_key *key, int enable)
{
- struct static_key_mod *mod = key->next;
+ const struct static_key_mod *mod = key->next;

while (mod) {
- struct module *m = mod->mod;
+ const struct module *m = mod->mod;

__jump_label_update(key, mod->entries,
m->jump_entries + m->num_jump_entries,
@@ -265,7 +267,7 @@ static void __jump_label_mod_update(struct static_key *key, int enable)
* loads patch these with arch_get_jump_label_nop(), which is specified by
* the arch specific jump label code.
*/
-void jump_label_apply_nops(struct module *mod)
+void jump_label_apply_nops(const struct module *mod)
{
struct jump_entry *iter_start = mod->jump_entries;
struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
@@ -425,7 +427,7 @@ early_initcall(jump_label_init_module);
*
* returns 1 if there is an overlap, 0 otherwise
*/
-int jump_label_text_reserved(void *start, void *end)
+int jump_label_text_reserved(const void *start, const void *end)
{
int ret = __jump_label_text_reserved(__start___jump_table,
__stop___jump_table, start, end);
@@ -439,13 +441,13 @@ int jump_label_text_reserved(void *start, void *end)
return ret;
}

-static void jump_label_update(struct static_key *key, int enable)
+static void jump_label_update(const struct static_key *key, int enable)
{
- struct jump_entry *stop = __stop___jump_table;
- struct jump_entry *entry = jump_label_get_entries(key);
+ const struct jump_entry *stop = __stop___jump_table;
+ const struct jump_entry *entry = jump_label_get_entries(key);

#ifdef CONFIG_MODULES
- struct module *mod = __module_address((unsigned long)key);
+ const struct module *mod = __module_address((unsigned long)key);

__jump_label_mod_update(key, enable);




--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/