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Message-ID: <52FB7D96.2050100@oracle.com>
Date: Wed, 12 Feb 2014 08:56:38 -0500
From: Sasha Levin <sasha.levin@...cle.com>
To: rostedt@...dmis.org
CC: linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org,
Sasha Levin <sasha.levin@...cle.com>
Subject: Re: [PATCH] jump label: constify lookup functions
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@...cle.com>
> ---
> 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);
>
>
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