lkml.org 
[lkml]   [2011]   [Feb]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    SubjectRe: [PATCH 0/2] jump label: 2.6.38 updates
    From
    Date
    On Fri, 2011-02-11 at 22:38 +0100, Peter Zijlstra wrote:
    >
    > So why can't we make that jump_label_entry::refcount and
    > jump_label_key::state an atomic_t and be done with it?

    So I had a bit of a poke at this because I didn't quite understand why
    all that stuff was as it was. I applied both Jason's patches and then
    basically rewrote kernel/jump_label.c just for kicks ;-)

    I haven't tried compiling this, let alone running it, but provided I
    didn't actually forget anything the storage per key is now 16 bytes when
    modules are disabled and 24 * (1 + mods) bytes for when they are
    enabled. The old code had 64 + 40 * mods bytes.

    I still need to clean up the static_branch_else bits and look at !x86
    aside from the already mentioned bits.. but what do people think?

    ---
    arch/sparc/include/asm/jump_label.h | 25 +-
    arch/x86/include/asm/jump_label.h | 22 +-
    arch/x86/kernel/jump_label.c | 2 +-
    arch/x86/kernel/module.c | 3 -
    include/linux/dynamic_debug.h | 10 +-
    include/linux/jump_label.h | 71 +++---
    include/linux/jump_label_ref.h | 36 +--
    include/linux/module.h | 1 +
    include/linux/perf_event.h | 28 +-
    include/linux/tracepoint.h | 8 +-
    kernel/jump_label.c | 516 +++++++++++++----------------------
    kernel/module.c | 7 +
    kernel/perf_event.c | 30 ++-
    kernel/timer.c | 8 +-
    kernel/tracepoint.c | 22 +-
    15 files changed, 333 insertions(+), 456 deletions(-)

    diff --git a/arch/sparc/include/asm/jump_label.h b/arch/sparc/include/asm/jump_label.h
    index 427d468..e4ca085 100644
    --- a/arch/sparc/include/asm/jump_label.h
    +++ b/arch/sparc/include/asm/jump_label.h
    @@ -7,17 +7,20 @@

    #define JUMP_LABEL_NOP_SIZE 4

    -#define JUMP_LABEL(key, label) \
    - do { \
    - asm goto("1:\n\t" \
    - "nop\n\t" \
    - "nop\n\t" \
    - ".pushsection __jump_table, \"a\"\n\t"\
    - ".align 4\n\t" \
    - ".word 1b, %l[" #label "], %c0\n\t" \
    - ".popsection \n\t" \
    - : : "i" (key) : : label);\
    - } while (0)
    +static __always_inline bool __static_branch(struct jump_label_key *key)
    +{
    + asm goto("1:\n\t"
    + "nop\n\t"
    + "nop\n\t"
    + ".pushsection __jump_table, \"a\"\n\t"
    + ".align 4\n\t"
    + ".word 1b, %l[l_yes], %c0\n\t"
    + ".popsection \n\t"
    + : : "i" (key) : : l_yes);
    + return false;
    +l_yes:
    + return true;
    +}

    #endif /* __KERNEL__ */

    diff --git a/arch/x86/include/asm/jump_label.h b/arch/x86/include/asm/jump_label.h
    index 574dbc2..3d44a7c 100644
    --- a/arch/x86/include/asm/jump_label.h
    +++ b/arch/x86/include/asm/jump_label.h
    @@ -5,20 +5,24 @@

    #include <linux/types.h>
    #include <asm/nops.h>
    +#include <asm/asm.h>

    #define JUMP_LABEL_NOP_SIZE 5

    # define JUMP_LABEL_INITIAL_NOP ".byte 0xe9 \n\t .long 0\n\t"

    -# define JUMP_LABEL(key, label) \
    - do { \
    - asm goto("1:" \
    - JUMP_LABEL_INITIAL_NOP \
    - ".pushsection __jump_table, \"aw\" \n\t"\
    - _ASM_PTR "1b, %l[" #label "], %c0 \n\t" \
    - ".popsection \n\t" \
    - : : "i" (key) : : label); \
    - } while (0)
    +static __always_inline bool __static_branch(struct jump_label_key *key)
    +{
    + asm goto("1:"
    + JUMP_LABEL_INITIAL_NOP
    + ".pushsection __jump_table, \"a\" \n\t"
    + _ASM_PTR "1b, %l[l_yes], %c0 \n\t"
    + ".popsection \n\t"
    + : : "i" (key) : : l_yes );
    + return false;
    +l_yes:
    + return true;
    +}

    #endif /* __KERNEL__ */

    diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c
    index 961b6b3..dfa4c3c 100644
    --- a/arch/x86/kernel/jump_label.c
    +++ b/arch/x86/kernel/jump_label.c
    @@ -4,13 +4,13 @@
    * Copyright (C) 2009 Jason Baron <jbaron@redhat.com>
    *
    */
    -#include <linux/jump_label.h>
    #include <linux/memory.h>
    #include <linux/uaccess.h>
    #include <linux/module.h>
    #include <linux/list.h>
    #include <linux/jhash.h>
    #include <linux/cpu.h>
    +#include <linux/jump_label.h>
    #include <asm/kprobes.h>
    #include <asm/alternative.h>

    diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
    index ab23f1a..0e6b823 100644
    --- a/arch/x86/kernel/module.c
    +++ b/arch/x86/kernel/module.c
    @@ -230,9 +230,6 @@ int module_finalize(const Elf_Ehdr *hdr,
    apply_paravirt(pseg, pseg + para->sh_size);
    }

    - /* make jump label nops */
    - jump_label_apply_nops(me);
    -
    return 0;
    }

    diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
    index 1c70028..2ade291 100644
    --- a/include/linux/dynamic_debug.h
    +++ b/include/linux/dynamic_debug.h
    @@ -33,7 +33,7 @@ struct _ddebug {
    #define _DPRINTK_FLAGS_PRINT (1<<0) /* printk() a message using the format */
    #define _DPRINTK_FLAGS_DEFAULT 0
    unsigned int flags:8;
    - char enabled;
    + struct jump_label_key enabled;
    } __attribute__((aligned(8)));


    @@ -48,8 +48,8 @@ extern int ddebug_remove_module(const char *mod_name);
    __used \
    __attribute__((section("__verbose"), aligned(8))) = \
    { KBUILD_MODNAME, __func__, __FILE__, fmt, __LINE__, \
    - _DPRINTK_FLAGS_DEFAULT }; \
    - if (unlikely(descriptor.enabled)) \
    + _DPRINTK_FLAGS_DEFAULT, JUMP_LABEL_INIT }; \
    + if (static_branch(&descriptor.enabled)) \
    printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); \
    } while (0)

    @@ -59,8 +59,8 @@ extern int ddebug_remove_module(const char *mod_name);
    __used \
    __attribute__((section("__verbose"), aligned(8))) = \
    { KBUILD_MODNAME, __func__, __FILE__, fmt, __LINE__, \
    - _DPRINTK_FLAGS_DEFAULT }; \
    - if (unlikely(descriptor.enabled)) \
    + _DPRINTK_FLAGS_DEFAULT, JUMP_LABEL_INIT }; \
    + if (static_branch(&descriptor.enabled)) \
    dev_printk(KERN_DEBUG, dev, fmt, ##__VA_ARGS__); \
    } while (0)

    diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
    index 7880f18..a1cec0a 100644
    --- a/include/linux/jump_label.h
    +++ b/include/linux/jump_label.h
    @@ -2,19 +2,35 @@
    #define _LINUX_JUMP_LABEL_H

    #if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
    +
    +struct jump_label_key {
    + atomic_t enabled;
    + struct jump_entry *entries;
    +#ifdef CONFIG_MODULES
    + struct jump_module *next;
    +#endif
    +};
    +
    # include <asm/jump_label.h>
    # define HAVE_JUMP_LABEL
    #endif

    enum jump_label_type {
    + JUMP_LABEL_DISABLE = 0,
    JUMP_LABEL_ENABLE,
    - JUMP_LABEL_DISABLE
    };

    struct module;

    +#define JUMP_LABEL_INIT { 0 }
    +
    #ifdef HAVE_JUMP_LABEL

    +static __always_inline bool static_branch(struct jump_label_key *key)
    +{
    + return __static_branch(key);
    +}
    +
    extern struct jump_entry __start___jump_table[];
    extern struct jump_entry __stop___jump_table[];

    @@ -23,37 +39,31 @@ extern void jump_label_unlock(void);
    extern void arch_jump_label_transform(struct jump_entry *entry,
    enum jump_label_type type);
    extern void arch_jump_label_text_poke_early(jump_label_t addr);
    -extern void jump_label_update(unsigned long key, enum jump_label_type type);
    -extern void jump_label_apply_nops(struct module *mod);
    extern int jump_label_text_reserved(void *start, void *end);
    -
    -#define jump_label_enable(key) \
    - jump_label_update((unsigned long)key, JUMP_LABEL_ENABLE);
    -
    -#define jump_label_disable(key) \
    - jump_label_update((unsigned long)key, JUMP_LABEL_DISABLE);
    +extern void jump_label_enable(struct jump_label_key *key);
    +extern void jump_label_disable(struct jump_label_key *key);

    #else

    -#define JUMP_LABEL(key, label) \
    -do { \
    - if (unlikely(*key)) \
    - goto label; \
    -} while (0)
    +struct jump_label_key {
    + atomic_t enabled;
    +};

    -#define jump_label_enable(cond_var) \
    -do { \
    - *(cond_var) = 1; \
    -} while (0)
    +static __always_inline bool static_branch(struct jump_label_key *key)
    +{
    + if (unlikely(atomic_read(&key->state)))
    + return true;
    + return false;
    +}

    -#define jump_label_disable(cond_var) \
    -do { \
    - *(cond_var) = 0; \
    -} while (0)
    +static inline void jump_label_enable(struct jump_label_key *key)
    +{
    + atomic_inc(&key->state);
    +}

    -static inline int jump_label_apply_nops(struct module *mod)
    +static inline void jump_label_disable(struct jump_label_key *key)
    {
    - return 0;
    + atomic_dec(&key->state);
    }

    static inline int jump_label_text_reserved(void *start, void *end)
    @@ -66,14 +76,9 @@ static inline void jump_label_unlock(void) {}

    #endif

    -#define COND_STMT(key, stmt) \
    -do { \
    - __label__ jl_enabled; \
    - JUMP_LABEL(key, jl_enabled); \
    - if (0) { \
    -jl_enabled: \
    - stmt; \
    - } \
    -} while (0)
    +static inline bool jump_label_enabled(struct jump_label_key *key)
    +{
    + return !!atomic_read(&key->state);
    +}

    #endif
    diff --git a/include/linux/jump_label_ref.h b/include/linux/jump_label_ref.h
    index e5d012a..5178696 100644
    --- a/include/linux/jump_label_ref.h
    +++ b/include/linux/jump_label_ref.h
    @@ -4,41 +4,27 @@
    #include <linux/jump_label.h>
    #include <asm/atomic.h>

    -#ifdef HAVE_JUMP_LABEL
    +struct jump_label_key_counter {
    + atomic_t ref;
    + struct jump_label_key key;
    +};

    -static inline void jump_label_inc(atomic_t *key)
    -{
    - if (atomic_add_return(1, key) == 1)
    - jump_label_enable(key);
    -}
    +#ifdef HAVE_JUMP_LABEL

    -static inline void jump_label_dec(atomic_t *key)
    +static __always_inline bool static_branch_else_atomic_read(struct jump_label_key *key, atomic_t *count)
    {
    - if (atomic_dec_and_test(key))
    - jump_label_disable(key);
    + return __static_branch(key);
    }

    #else /* !HAVE_JUMP_LABEL */

    -static inline void jump_label_inc(atomic_t *key)
    +static __always_inline bool static_branch_else_atomic_read(struct jump_label_key *key, atomic_t *count)
    {
    - atomic_inc(key);
    + if (unlikely(atomic_read(count)))
    + return true;
    + return false;
    }

    -static inline void jump_label_dec(atomic_t *key)
    -{
    - atomic_dec(key);
    -}
    -
    -#undef JUMP_LABEL
    -#define JUMP_LABEL(key, label) \
    -do { \
    - if (unlikely(__builtin_choose_expr( \
    - __builtin_types_compatible_p(typeof(key), atomic_t *), \
    - atomic_read((atomic_t *)(key)), *(key)))) \
    - goto label; \
    -} while (0)
    -
    #endif /* HAVE_JUMP_LABEL */

    #endif /* _LINUX_JUMP_LABEL_REF_H */
    diff --git a/include/linux/module.h b/include/linux/module.h
    index 9bdf27c..eeb3e99 100644
    --- a/include/linux/module.h
    +++ b/include/linux/module.h
    @@ -266,6 +266,7 @@ enum module_state
    MODULE_STATE_LIVE,
    MODULE_STATE_COMING,
    MODULE_STATE_GOING,
    + MODULE_STATE_POST_RELOCATE,
    };

    struct module
    diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
    index dda5b0a..26fe115 100644
    --- a/include/linux/perf_event.h
    +++ b/include/linux/perf_event.h
    @@ -1000,7 +1000,7 @@ static inline int is_software_event(struct perf_event *event)
    return event->pmu->task_ctx_nr == perf_sw_context;
    }

    -extern atomic_t perf_swevent_enabled[PERF_COUNT_SW_MAX];
    +extern struct jump_label_key_counter perf_swevent_enabled[PERF_COUNT_SW_MAX];

    extern void __perf_sw_event(u32, u64, int, struct pt_regs *, u64);

    @@ -1029,30 +1029,32 @@ perf_sw_event(u32 event_id, u64 nr, int nmi, struct pt_regs *regs, u64 addr)
    {
    struct pt_regs hot_regs;

    - JUMP_LABEL(&perf_swevent_enabled[event_id], have_event);
    - return;
    -
    -have_event:
    - if (!regs) {
    - perf_fetch_caller_regs(&hot_regs);
    - regs = &hot_regs;
    + if (static_branch_else_atomic_read(&perf_swevent_enabled[event_id].key,
    + &perf_swevent_enabled[event_id].ref)) {
    + if (!regs) {
    + perf_fetch_caller_regs(&hot_regs);
    + regs = &hot_regs;
    + }
    + __perf_sw_event(event_id, nr, nmi, regs, addr);
    }
    - __perf_sw_event(event_id, nr, nmi, regs, addr);
    }

    -extern atomic_t perf_task_events;
    +extern struct jump_label_key_counter perf_task_events;

    static inline void perf_event_task_sched_in(struct task_struct *task)
    {
    - COND_STMT(&perf_task_events, __perf_event_task_sched_in(task));
    + if (static_branch_else_atomic_read(&perf_task_events.key,
    + &perf_task_events.ref))
    + __perf_event_task_sched_in(task);
    }

    static inline
    void perf_event_task_sched_out(struct task_struct *task, struct task_struct *next)
    {
    perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, NULL, 0);
    -
    - COND_STMT(&perf_task_events, __perf_event_task_sched_out(task, next));
    + if (static_branch_else_atomic_read(&perf_task_events.key,
    + &perf_task_events.ref))
    + __perf_event_task_sched_out(task, next);
    }

    extern void perf_event_mmap(struct vm_area_struct *vma);
    diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
    index 97c84a5..6c8c747 100644
    --- a/include/linux/tracepoint.h
    +++ b/include/linux/tracepoint.h
    @@ -29,7 +29,7 @@ struct tracepoint_func {

    struct tracepoint {
    const char *name; /* Tracepoint name */
    - int state; /* State. */
    + struct jump_label_key key;
    void (*regfunc)(void);
    void (*unregfunc)(void);
    struct tracepoint_func __rcu *funcs;
    @@ -146,9 +146,7 @@ void tracepoint_update_probe_range(struct tracepoint * const *begin,
    extern struct tracepoint __tracepoint_##name; \
    static inline void trace_##name(proto) \
    { \
    - JUMP_LABEL(&__tracepoint_##name.state, do_trace); \
    - return; \
    -do_trace: \
    + if (static_branch(&__tracepoint_##name.key)) \
    __DO_TRACE(&__tracepoint_##name, \
    TP_PROTO(data_proto), \
    TP_ARGS(data_args), \
    @@ -181,7 +179,7 @@ do_trace: \
    __attribute__((section("__tracepoints_strings"))) = #name; \
    struct tracepoint __tracepoint_##name \
    __attribute__((section("__tracepoints"))) = \
    - { __tpstrtab_##name, 0, reg, unreg, NULL }; \
    + { __tpstrtab_##name, JUMP_LABEL_INIT, reg, unreg, NULL };\
    static struct tracepoint * const __tracepoint_ptr_##name __used \
    __attribute__((section("__tracepoints_ptrs"))) = \
    &__tracepoint_##name;
    diff --git a/kernel/jump_label.c b/kernel/jump_label.c
    index 3b79bd9..29b34be 100644
    --- a/kernel/jump_label.c
    +++ b/kernel/jump_label.c
    @@ -2,9 +2,9 @@
    * jump label support
    *
    * Copyright (C) 2009 Jason Baron <jbaron@redhat.com>
    + * Copyright (C) 2011 Peter Zijlstra <pzijlstr@redhat.com>
    *
    */
    -#include <linux/jump_label.h>
    #include <linux/memory.h>
    #include <linux/uaccess.h>
    #include <linux/module.h>
    @@ -13,32 +13,13 @@
    #include <linux/slab.h>
    #include <linux/sort.h>
    #include <linux/err.h>
    +#include <linux/jump_label.h>

    #ifdef HAVE_JUMP_LABEL

    -#define JUMP_LABEL_HASH_BITS 6
    -#define JUMP_LABEL_TABLE_SIZE (1 << JUMP_LABEL_HASH_BITS)
    -static struct hlist_head jump_label_table[JUMP_LABEL_TABLE_SIZE];
    -
    /* mutex to protect coming/going of the the jump_label table */
    static DEFINE_MUTEX(jump_label_mutex);

    -struct jump_label_entry {
    - struct hlist_node hlist;
    - struct jump_entry *table;
    - int nr_entries;
    - /* hang modules off here */
    - struct hlist_head modules;
    - unsigned long key;
    -};
    -
    -struct jump_label_module_entry {
    - struct hlist_node hlist;
    - struct jump_entry *table;
    - int nr_entries;
    - struct module *mod;
    -};
    -
    void jump_label_lock(void)
    {
    mutex_lock(&jump_label_mutex);
    @@ -64,7 +45,7 @@ static int jump_label_cmp(const void *a, const void *b)
    }

    static void
    -sort_jump_label_entries(struct jump_entry *start, struct jump_entry *stop)
    +jump_label_sort_entries(struct jump_entry *start, struct jump_entry *stop)
    {
    unsigned long size;

    @@ -73,118 +54,25 @@ sort_jump_label_entries(struct jump_entry *start, struct jump_entry *stop)
    sort(start, size, sizeof(struct jump_entry), jump_label_cmp, NULL);
    }

    -static struct jump_label_entry *get_jump_label_entry(jump_label_t key)
    -{
    - struct hlist_head *head;
    - struct hlist_node *node;
    - struct jump_label_entry *e;
    - u32 hash = jhash((void *)&key, sizeof(jump_label_t), 0);
    -
    - head = &jump_label_table[hash & (JUMP_LABEL_TABLE_SIZE - 1)];
    - hlist_for_each_entry(e, node, head, hlist) {
    - if (key == e->key)
    - return e;
    - }
    - return NULL;
    -}
    +static void jump_label_update(struct jump_label_key *key, int enable);

    -static struct jump_label_entry *
    -add_jump_label_entry(jump_label_t key, int nr_entries, struct jump_entry *table)
    +void jump_label_enable(struct jump_label_key *key)
    {
    - struct hlist_head *head;
    - struct jump_label_entry *e;
    - u32 hash;
    -
    - e = get_jump_label_entry(key);
    - if (e)
    - return ERR_PTR(-EEXIST);
    -
    - e = kmalloc(sizeof(struct jump_label_entry), GFP_KERNEL);
    - if (!e)
    - return ERR_PTR(-ENOMEM);
    -
    - hash = jhash((void *)&key, sizeof(jump_label_t), 0);
    - head = &jump_label_table[hash & (JUMP_LABEL_TABLE_SIZE - 1)];
    - e->key = key;
    - e->table = table;
    - e->nr_entries = nr_entries;
    - INIT_HLIST_HEAD(&(e->modules));
    - hlist_add_head(&e->hlist, head);
    - return e;
    -}
    + if (atomic_inc_not_zero(&key->enabled))
    + return;

    -static int
    -build_jump_label_hashtable(struct jump_entry *start, struct jump_entry *stop)
    -{
    - struct jump_entry *iter, *iter_begin;
    - struct jump_label_entry *entry;
    - int count;
    -
    - sort_jump_label_entries(start, stop);
    - iter = start;
    - while (iter < stop) {
    - entry = get_jump_label_entry(iter->key);
    - if (!entry) {
    - iter_begin = iter;
    - count = 0;
    - while ((iter < stop) &&
    - (iter->key == iter_begin->key)) {
    - iter++;
    - count++;
    - }
    - entry = add_jump_label_entry(iter_begin->key,
    - count, iter_begin);
    - if (IS_ERR(entry))
    - return PTR_ERR(entry);
    - } else {
    - WARN_ONCE(1, KERN_ERR "build_jump_hashtable: unexpected entry!\n");
    - return -1;
    - }
    - }
    - return 0;
    + jump_label_lock();
    + if (atomic_add_return(&key->enabled) == 1)
    + jump_label_update(key, JUMP_LABEL_ENABLE);
    + jump_label_unlock();
    }

    -/***
    - * jump_label_update - update jump label text
    - * @key - key value associated with a a jump label
    - * @type - enum set to JUMP_LABEL_ENABLE or JUMP_LABEL_DISABLE
    - *
    - * Will enable/disable the jump for jump label @key, depending on the
    - * value of @type.
    - *
    - */
    -
    -void jump_label_update(unsigned long key, enum jump_label_type type)
    +void jump_label_disable(struct jump_label_key *key)
    {
    - struct jump_entry *iter;
    - struct jump_label_entry *entry;
    - struct hlist_node *module_node;
    - struct jump_label_module_entry *e_module;
    - int count;
    + if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex))
    + return;

    - jump_label_lock();
    - entry = get_jump_label_entry((jump_label_t)key);
    - if (entry) {
    - count = entry->nr_entries;
    - iter = entry->table;
    - while (count--) {
    - if (kernel_text_address(iter->code))
    - arch_jump_label_transform(iter, type);
    - iter++;
    - }
    - /* eanble/disable jump labels in modules */
    - hlist_for_each_entry(e_module, module_node, &(entry->modules),
    - hlist) {
    - count = e_module->nr_entries;
    - iter = e_module->table;
    - while (count--) {
    - if (iter->key &&
    - kernel_text_address(iter->code))
    - arch_jump_label_transform(iter, type);
    - iter++;
    - }
    - }
    - }
    + jump_label_update(key, JUMP_LABEL_DISABLE);
    jump_label_unlock();
    }

    @@ -197,77 +85,30 @@ static int addr_conflict(struct jump_entry *entry, void *start, void *end)
    return 0;
    }

    -#ifdef CONFIG_MODULES
    -
    -static int module_conflict(void *start, void *end)
    -{
    - struct hlist_head *head;
    - struct hlist_node *node, *node_next, *module_node, *module_node_next;
    - struct jump_label_entry *e;
    - struct jump_label_module_entry *e_module;
    - struct jump_entry *iter;
    - int i, count;
    - int conflict = 0;
    -
    - for (i = 0; i < JUMP_LABEL_TABLE_SIZE; i++) {
    - head = &jump_label_table[i];
    - hlist_for_each_entry_safe(e, node, node_next, head, hlist) {
    - hlist_for_each_entry_safe(e_module, module_node,
    - module_node_next,
    - &(e->modules), hlist) {
    - count = e_module->nr_entries;
    - iter = e_module->table;
    - while (count--) {
    - if (addr_conflict(iter, start, end)) {
    - conflict = 1;
    - goto out;
    - }
    - iter++;
    - }
    - }
    - }
    - }
    -out:
    - return conflict;
    -}
    -
    -#endif
    -
    -/***
    - * jump_label_text_reserved - check if addr range is reserved
    - * @start: start text addr
    - * @end: end text addr
    - *
    - * checks if the text addr located between @start and @end
    - * overlaps with any of the jump label patch addresses. Code
    - * that wants to modify kernel text should first verify that
    - * it does not overlap with any of the jump label addresses.
    - * Caller must hold jump_label_mutex.
    - *
    - * returns 1 if there is an overlap, 0 otherwise
    - */
    -int jump_label_text_reserved(void *start, void *end)
    +static int __jump_label_text_reserved(struct jump_entry *iter_start,
    + struct jump_entry *iter_stop, void *start, void *end)
    {
    struct jump_entry *iter;
    - struct jump_entry *iter_start = __start___jump_table;
    - struct jump_entry *iter_stop = __start___jump_table;
    - int conflict = 0;

    iter = iter_start;
    while (iter < iter_stop) {
    - if (addr_conflict(iter, start, end)) {
    - conflict = 1;
    - goto out;
    - }
    + if (addr_conflict(iter, start, end))
    + return 1;
    iter++;
    }

    - /* now check modules */
    -#ifdef CONFIG_MODULES
    - conflict = module_conflict(start, end);
    -#endif
    -out:
    - return conflict;
    + return 0;
    +}
    +
    +static void __jump_label_update(struct jump_label_key *key,
    + struct jump_entry *entry, int enable)
    +{
    + for (; entry->key == (jump_label_t)key; entry++) {
    + if (WARN_ON_ONCE(!kernel_text_address(iter->code)))
    + continue;
    +
    + arch_jump_label_transform(iter, enable);
    + }
    }

    /*
    @@ -277,141 +118,155 @@ void __weak arch_jump_label_text_poke_early(jump_label_t addr)
    {
    }

    -static __init int init_jump_label(void)
    +static __init int jump_label_init(void)
    {
    - int ret;
    struct jump_entry *iter_start = __start___jump_table;
    struct jump_entry *iter_stop = __stop___jump_table;
    + struct jump_label_key *key = NULL;
    struct jump_entry *iter;

    jump_label_lock();
    - ret = build_jump_label_hashtable(__start___jump_table,
    - __stop___jump_table);
    - iter = iter_start;
    - while (iter < iter_stop) {
    + jump_label_sort_entries(iter_start, iter_stop);
    +
    + for (iter = iter_start; iter < iter_stop; iter++) {
    arch_jump_label_text_poke_early(iter->code);
    - iter++;
    + if (iter->key == (jump_label_t)key)
    + continue;
    +
    + key = (struct jump_label_key *)iter->key;
    + atomic_set(&key->enabled, 0);
    + key->entries = iter;
    +#ifdef CONFIG_MODULES
    + key->next = NULL;
    +#endif
    }
    jump_label_unlock();
    - return ret;
    +
    + return 0;
    }
    -early_initcall(init_jump_label);
    +early_initcall(jump_label_init);

    #ifdef CONFIG_MODULES

    -static struct jump_label_module_entry *
    -add_jump_label_module_entry(struct jump_label_entry *entry,
    - struct jump_entry *iter_begin,
    - int count, struct module *mod)
    -{
    - struct jump_label_module_entry *e;
    -
    - e = kmalloc(sizeof(struct jump_label_module_entry), GFP_KERNEL);
    - if (!e)
    - return ERR_PTR(-ENOMEM);
    - e->mod = mod;
    - e->nr_entries = count;
    - e->table = iter_begin;
    - hlist_add_head(&e->hlist, &entry->modules);
    - return e;
    -}
    +struct jump_label_mod {
    + struct jump_label_mod *next;
    + struct jump_entry *entries;
    + struct module *mod;
    +};

    -static int add_jump_label_module(struct module *mod)
    +static int __jump_label_mod_text_reserved(void *start, void *end)
    {
    - struct jump_entry *iter, *iter_begin;
    - struct jump_label_entry *entry;
    - struct jump_label_module_entry *module_entry;
    - int count;
    + struct module *mod;

    - /* if the module doesn't have jump label entries, just return */
    - if (!mod->num_jump_entries)
    + mod = __module_text_address(start);
    + if (!mod)
    return 0;

    - sort_jump_label_entries(mod->jump_entries,
    + WARN_ON_ONCE(__module_text_address(end) != mod);
    +
    + return __jump_label_text_reserved(mod->jump_entries,
    mod->jump_entries + mod->num_jump_entries);
    - iter = mod->jump_entries;
    - while (iter < mod->jump_entries + mod->num_jump_entries) {
    - entry = get_jump_label_entry(iter->key);
    - iter_begin = iter;
    - count = 0;
    - while ((iter < mod->jump_entries + mod->num_jump_entries) &&
    - (iter->key == iter_begin->key)) {
    - iter++;
    - count++;
    - }
    - if (!entry) {
    - entry = add_jump_label_entry(iter_begin->key, 0, NULL);
    - if (IS_ERR(entry))
    - return PTR_ERR(entry);
    - }
    - module_entry = add_jump_label_module_entry(entry, iter_begin,
    - count, mod);
    - if (IS_ERR(module_entry))
    - return PTR_ERR(module_entry);
    +}
    +
    +static void __jump_label_mod_update(struct jump_label_key *key, int enable)
    +{
    + struct jump_label_mod *mod = key->next;
    +
    + while (mod) {
    + __jump_label_update(key, mod->entries, enable);
    + mod = mod->next;
    }
    - return 0;
    }

    -static void remove_jump_label_module(struct module *mod)
    +/***
    + * apply_jump_label_nops - patch module jump labels with arch_get_jump_label_nop()
    + * @mod: module to patch
    + *
    + * Allow for run-time selection of the optimal nops. Before the module
    + * loads patch these with arch_get_jump_label_nop(), which is specified by
    + * the arch specific jump label code.
    + */
    +static void jump_label_apply_nops(struct module *mod)
    {
    - struct hlist_head *head;
    - struct hlist_node *node, *node_next, *module_node, *module_node_next;
    - struct jump_label_entry *e;
    - struct jump_label_module_entry *e_module;
    - int i;
    + struct jump_entry *iter_start = mod->jump_entries;
    + struct jump_entry *iter_stop = mod->jump_entries + mod->num_jump_entries;
    + struct jump_entry *iter;

    /* if the module doesn't have jump label entries, just return */
    - if (!mod->num_jump_entries)
    + if (iter_start == iter_stop)
    return;

    - for (i = 0; i < JUMP_LABEL_TABLE_SIZE; i++) {
    - head = &jump_label_table[i];
    - hlist_for_each_entry_safe(e, node, node_next, head, hlist) {
    - hlist_for_each_entry_safe(e_module, module_node,
    - module_node_next,
    - &(e->modules), hlist) {
    - if (e_module->mod == mod) {
    - hlist_del(&e_module->hlist);
    - kfree(e_module);
    - }
    - }
    - if (hlist_empty(&e->modules) && (e->nr_entries == 0)) {
    - hlist_del(&e->hlist);
    - kfree(e);
    - }
    + jump_label_sort_entries(iter_start, iter_stop);
    +
    + for (iter = iter_start; iter < iter_stop; iter++)
    + arch_jump_label_text_poke_early(iter->code);
    +}
    +
    +static int jump_label_add_module(struct module *mod)
    +{
    + struct jump_entry *iter_start = mod->jump_entries;
    + struct jump_entry *iter_stop = mod->jump_entries + mod->num_jump_entries;
    + struct jump_entry *iter;
    + struct jump_label_key *key = NULL;
    + struct jump_label_mod *jlm;
    +
    + for (iter = iter_start; iter < iter_stop; iter++) {
    + if (iter->key == (jump_label_t)key)
    + continue;
    +
    + key = (struct jump_label_key)iter->key;
    +
    + if (__module_address(iter->key) == mod) {
    + atomic_set(&key->enabled, 0);
    + key->entries = iter;
    + key->next = NULL;
    + continue;
    }
    +
    + jlm = kzalloc(sizeof(struct jump_label_mod), GFP_KERNEL);
    + if (!jlm)
    + return -ENOMEM;
    +
    + jlm->mod = mod;
    + jlm->entries = iter;
    + jlm->next = key->next;
    + key->next = jlm;
    +
    + if (jump_label_enabled(key))
    + __jump_label_update(key, iter, JUMP_LABEL_ENABLE);
    }
    +
    + return 0;
    }

    -static void remove_jump_label_module_init(struct module *mod)
    +static void jump_label_del_module(struct module *mod)
    {
    - struct hlist_head *head;
    - struct hlist_node *node, *node_next, *module_node, *module_node_next;
    - struct jump_label_entry *e;
    - struct jump_label_module_entry *e_module;
    + struct jump_entry *iter_start = mod->jump_entries;
    + struct jump_entry *iter_stop = mod->jump_entries + mod->num_jump_entries;
    struct jump_entry *iter;
    - int i, count;
    + struct jump_label_key *key = NULL;
    + struct jump_label_mod *jlm, **prev;

    - /* if the module doesn't have jump label entries, just return */
    - if (!mod->num_jump_entries)
    - return;
    + for (iter = iter_start; iter < iter_stop; iter++) {
    + if (iter->key == (jump_label_t)key)
    + continue;
    +
    + key = (struct jump_label_key)iter->key;
    +
    + if (__module_address(iter->key) == mod)
    + continue;
    +
    + prev = &key->next;
    + jlm = key->next;
    +
    + while (jlm && jlm->mod != mod) {
    + prev = &jlm->next;
    + jlm = jlm->next;
    + }

    - for (i = 0; i < JUMP_LABEL_TABLE_SIZE; i++) {
    - head = &jump_label_table[i];
    - hlist_for_each_entry_safe(e, node, node_next, head, hlist) {
    - hlist_for_each_entry_safe(e_module, module_node,
    - module_node_next,
    - &(e->modules), hlist) {
    - if (e_module->mod != mod)
    - continue;
    - count = e_module->nr_entries;
    - iter = e_module->table;
    - while (count--) {
    - if (within_module_init(iter->code, mod))
    - iter->key = 0;
    - iter++;
    - }
    - }
    + if (jlm) {
    + *prev = jlm->next;
    + kfree(jlm);
    }
    }
    }
    @@ -424,61 +279,76 @@ jump_label_module_notify(struct notifier_block *self, unsigned long val,
    int ret = 0;

    switch (val) {
    - case MODULE_STATE_COMING:
    + case MODULE_STATE_POST_RELOCATE:
    jump_label_lock();
    - ret = add_jump_label_module(mod);
    - if (ret)
    - remove_jump_label_module(mod);
    + jump_label_apply_nops(mod);
    jump_label_unlock();
    break;
    - case MODULE_STATE_GOING:
    + case MODULE_STATE_COMING:
    jump_label_lock();
    - remove_jump_label_module(mod);
    + ret = jump_label_add_module(mod);
    + if (ret)
    + jump_label_del_module(mod);
    jump_label_unlock();
    break;
    - case MODULE_STATE_LIVE:
    + case MODULE_STATE_GOING:
    jump_label_lock();
    - remove_jump_label_module_init(mod);
    + jump_label_del_module(mod);
    jump_label_unlock();
    break;
    }
    return ret;
    }

    +struct notifier_block jump_label_module_nb = {
    + .notifier_call = jump_label_module_notify,
    + .priority = 1, /* higher than tracepoints */
    +};
    +
    +static __init int jump_label_init_module(void)
    +{
    + return register_module_notifier(&jump_label_module_nb);
    +}
    +early_initcall(jump_label_init_module);
    +
    +#endif /* CONFIG_MODULES */
    +
    /***
    - * apply_jump_label_nops - patch module jump labels with arch_get_jump_label_nop()
    - * @mod: module to patch
    + * jump_label_text_reserved - check if addr range is reserved
    + * @start: start text addr
    + * @end: end text addr
    *
    - * Allow for run-time selection of the optimal nops. Before the module
    - * loads patch these with arch_get_jump_label_nop(), which is specified by
    - * the arch specific jump label code.
    + * checks if the text addr located between @start and @end
    + * overlaps with any of the jump label patch addresses. Code
    + * that wants to modify kernel text should first verify that
    + * it does not overlap with any of the jump label addresses.
    + * Caller must hold jump_label_mutex.
    + *
    + * returns 1 if there is an overlap, 0 otherwise
    */
    -void jump_label_apply_nops(struct module *mod)
    +int jump_label_text_reserved(void *start, void *end)
    {
    - struct jump_entry *iter;
    + int ret = __jump_label_text_reserved(__start___jump_table,
    + __stop___jump_table, start, end);

    - /* if the module doesn't have jump label entries, just return */
    - if (!mod->num_jump_entries)
    - return;
    + if (ret)
    + return ret;

    - iter = mod->jump_entries;
    - while (iter < mod->jump_entries + mod->num_jump_entries) {
    - arch_jump_label_text_poke_early(iter->code);
    - iter++;
    - }
    +#ifdef CONFIG_MODULES
    + ret = __jump_label_mod_text_reserved(start, end);
    +#endif
    + return ret;
    }

    -struct notifier_block jump_label_module_nb = {
    - .notifier_call = jump_label_module_notify,
    - .priority = 0,
    -};
    -
    -static __init int init_jump_label_module(void)
    +static void jump_label_update(struct jump_label_key *key, int enable)
    {
    - return register_module_notifier(&jump_label_module_nb);
    -}
    -early_initcall(init_jump_label_module);
    + struct jump_entry *entry = key->entries;

    -#endif /* CONFIG_MODULES */
    + __jump_label_update(key, entry, enable);
    +
    +#ifdef CONFIG_MODULES
    + __jump_label_mod_update(key, enable);
    +#endif
    +}

    #endif
    diff --git a/kernel/module.c b/kernel/module.c
    index efa290e..890cadf 100644
    --- a/kernel/module.c
    +++ b/kernel/module.c
    @@ -2789,6 +2789,13 @@ static struct module *load_module(void __user *umod,
    goto unlock;
    }

    + err = blocking_notifier_call_chain(&module_notify_list,
    + MODULE_STATE_POST_RELOCATE, mod);
    + if (err != NOTIFY_DONE) {
    + err = notifier_to_errno(err);
    + goto unlock;
    + }
    +
    /* This has to be done once we're sure module name is unique. */
    if (!mod->taints)
    dynamic_debug_setup(info.debug, info.num_debug);
    diff --git a/kernel/perf_event.c b/kernel/perf_event.c
    index a353a4d..7bacdd3 100644
    --- a/kernel/perf_event.c
    +++ b/kernel/perf_event.c
    @@ -117,7 +117,7 @@ enum event_type_t {
    EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
    };

    -atomic_t perf_task_events __read_mostly;
    +struct jump_label_key_counter perf_task_events __read_mostly;
    static atomic_t nr_mmap_events __read_mostly;
    static atomic_t nr_comm_events __read_mostly;
    static atomic_t nr_task_events __read_mostly;
    @@ -2383,8 +2383,10 @@ static void free_event(struct perf_event *event)
    irq_work_sync(&event->pending);

    if (!event->parent) {
    - if (event->attach_state & PERF_ATTACH_TASK)
    - jump_label_dec(&perf_task_events);
    + if (event->attach_state & PERF_ATTACH_TASK) {
    + if (atomic_dec_and_test(&perf_task_events.ref))
    + jump_label_disable(&perf_task_events.key);
    + }
    if (event->attr.mmap || event->attr.mmap_data)
    atomic_dec(&nr_mmap_events);
    if (event->attr.comm)
    @@ -4912,7 +4914,7 @@ fail:
    return err;
    }

    -atomic_t perf_swevent_enabled[PERF_COUNT_SW_MAX];
    +struct jump_label_key_counter perf_swevent_enabled[PERF_COUNT_SW_MAX];

    static void sw_perf_event_destroy(struct perf_event *event)
    {
    @@ -4920,7 +4922,8 @@ static void sw_perf_event_destroy(struct perf_event *event)

    WARN_ON(event->parent);

    - jump_label_dec(&perf_swevent_enabled[event_id]);
    + if (atomic_dec_and_test(&perf_swevent_enabled[event_id].ref))
    + jump_label_disable(&perf_swevent_enabled[event_id].key);
    swevent_hlist_put(event);
    }

    @@ -4945,12 +4948,15 @@ static int perf_swevent_init(struct perf_event *event)

    if (!event->parent) {
    int err;
    + atomic_t *ref;

    err = swevent_hlist_get(event);
    if (err)
    return err;

    - jump_label_inc(&perf_swevent_enabled[event_id]);
    + ref = &perf_swevent_enabled[event_id].ref;
    + if (atomic_add_return(1, ref) == 1)
    + jump_label_enable(&perf_swevent_enabled[event_id].key);
    event->destroy = sw_perf_event_destroy;
    }

    @@ -5123,6 +5129,10 @@ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
    u64 period;

    event = container_of(hrtimer, struct perf_event, hw.hrtimer);
    +
    + if (event->state < PERF_EVENT_STATE_ACTIVE)
    + return HRTIMER_NORESTART;
    +
    event->pmu->read(event);

    perf_sample_data_init(&data, 0);
    @@ -5174,7 +5184,7 @@ static void perf_swevent_cancel_hrtimer(struct perf_event *event)
    ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
    local64_set(&hwc->period_left, ktime_to_ns(remaining));

    - hrtimer_cancel(&hwc->hrtimer);
    + hrtimer_try_to_cancel(&hwc->hrtimer);
    }
    }

    @@ -5713,8 +5723,10 @@ done:
    event->pmu = pmu;

    if (!event->parent) {
    - if (event->attach_state & PERF_ATTACH_TASK)
    - jump_label_inc(&perf_task_events);
    + if (event->attach_state & PERF_ATTACH_TASK) {
    + if (atomic_add_return(1, &perf_task_events.ref) == 1)
    + jump_label_enable(&perf_task_events.key);
    + }
    if (event->attr.mmap || event->attr.mmap_data)
    atomic_inc(&nr_mmap_events);
    if (event->attr.comm)
    diff --git a/kernel/timer.c b/kernel/timer.c
    index 343ff27..c848cd8 100644
    --- a/kernel/timer.c
    +++ b/kernel/timer.c
    @@ -959,7 +959,7 @@ EXPORT_SYMBOL(try_to_del_timer_sync);
    *
    * Synchronization rules: Callers must prevent restarting of the timer,
    * otherwise this function is meaningless. It must not be called from
    - * hardirq contexts. The caller must not hold locks which would prevent
    + * interrupt contexts. The caller must not hold locks which would prevent
    * completion of the timer's handler. The timer's handler must not call
    * add_timer_on(). Upon exit the timer is not queued and the handler is
    * not running on any CPU.
    @@ -971,12 +971,10 @@ int del_timer_sync(struct timer_list *timer)
    #ifdef CONFIG_LOCKDEP
    unsigned long flags;

    - raw_local_irq_save(flags);
    - local_bh_disable();
    + local_irq_save(flags);
    lock_map_acquire(&timer->lockdep_map);
    lock_map_release(&timer->lockdep_map);
    - _local_bh_enable();
    - raw_local_irq_restore(flags);
    + local_irq_restore(flags);
    #endif
    /*
    * don't use it in hardirq context, because it
    diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
    index 68187af..13066e8 100644
    --- a/kernel/tracepoint.c
    +++ b/kernel/tracepoint.c
    @@ -251,9 +251,9 @@ static void set_tracepoint(struct tracepoint_entry **entry,
    {
    WARN_ON(strcmp((*entry)->name, elem->name) != 0);

    - if (elem->regfunc && !elem->state && active)
    + if (elem->regfunc && !jump_label_enabled(&elem->key) && active)
    elem->regfunc();
    - else if (elem->unregfunc && elem->state && !active)
    + else if (elem->unregfunc && jump_label_enabled(&elem->key) && !active)
    elem->unregfunc();

    /*
    @@ -264,13 +264,10 @@ static void set_tracepoint(struct tracepoint_entry **entry,
    * is used.
    */
    rcu_assign_pointer(elem->funcs, (*entry)->funcs);
    - if (!elem->state && active) {
    - jump_label_enable(&elem->state);
    - elem->state = active;
    - } else if (elem->state && !active) {
    - jump_label_disable(&elem->state);
    - elem->state = active;
    - }
    + if (active)
    + jump_label_enable(&elem->key);
    + else if (!active)
    + jump_label_disable(&elem->key);
    }

    /*
    @@ -281,13 +278,10 @@ static void set_tracepoint(struct tracepoint_entry **entry,
    */
    static void disable_tracepoint(struct tracepoint *elem)
    {
    - if (elem->unregfunc && elem->state)
    + if (elem->unregfunc && jump_label_enabled(&elem->key))
    elem->unregfunc();

    - if (elem->state) {
    - jump_label_disable(&elem->state);
    - elem->state = 0;
    - }
    + jump_label_disable(&elem->key);
    rcu_assign_pointer(elem->funcs, NULL);
    }




    \
     
     \ /
      Last update: 2011-02-12 20:11    [W:0.120 / U:0.736 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site