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author | Linus Torvalds <torvalds@linux-foundation.org> | 2024-05-13 17:01:28 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2024-05-13 17:01:28 -0700 |
commit | 48fc82c40bc29a80361b1eab0e4a9494628a7144 (patch) | |
tree | e5be91e08b0e4b80e15b9c945ed715cffaa532bc /kernel/jump_label.c | |
parent | a7c840ba5fa78d7761b9fedc33d69cef44986d79 (diff) | |
parent | 532453e7aa78f3962fb4d86caf40ff81ebf62160 (diff) | |
download | linux-stable-48fc82c40bc29a80361b1eab0e4a9494628a7144.tar.gz linux-stable-48fc82c40bc29a80361b1eab0e4a9494628a7144.tar.bz2 linux-stable-48fc82c40bc29a80361b1eab0e4a9494628a7144.zip |
Merge tag 'locking-core-2024-05-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
- Over a dozen code generation micro-optimizations for the atomic
and spinlock code
- Add more __ro_after_init attributes
- Robustify the lockdevent_*() macros
* tag 'locking-core-2024-05-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/pvqspinlock/x86: Use _Q_LOCKED_VAL in PV_UNLOCK_ASM macro
locking/qspinlock/x86: Micro-optimize virt_spin_lock()
locking/atomic/x86: Merge __arch{,_try}_cmpxchg64_emu_local() with __arch{,_try}_cmpxchg64_emu()
locking/atomic/x86: Introduce arch_try_cmpxchg64_local()
locking/pvqspinlock/x86: Remove redundant CMP after CMPXCHG in __raw_callee_save___pv_queued_spin_unlock()
locking/pvqspinlock: Use try_cmpxchg() in qspinlock_paravirt.h
locking/pvqspinlock: Use try_cmpxchg_acquire() in trylock_clear_pending()
locking/qspinlock: Use atomic_try_cmpxchg_relaxed() in xchg_tail()
locking/atomic/x86: Define arch_atomic_sub() family using arch_atomic_add() functions
locking/atomic/x86: Rewrite x86_32 arch_atomic64_{,fetch}_{and,or,xor}() functions
locking/atomic/x86: Introduce arch_atomic64_read_nonatomic() to x86_32
locking/atomic/x86: Introduce arch_atomic64_try_cmpxchg() to x86_32
locking/atomic/x86: Introduce arch_try_cmpxchg64() for !CONFIG_X86_CMPXCHG64
locking/atomic/x86: Modernize x86_32 arch_{,try_}_cmpxchg64{,_local}()
locking/atomic/x86: Correct the definition of __arch_try_cmpxchg128()
x86/tsc: Make __use_tsc __ro_after_init
x86/kvm: Make kvm_async_pf_enabled __ro_after_init
context_tracking: Make context_tracking_key __ro_after_init
jump_label,module: Don't alloc static_key_mod for __ro_after_init keys
locking/qspinlock: Always evaluate lockevent* non-event parameter once
Diffstat (limited to 'kernel/jump_label.c')
-rw-r--r-- | kernel/jump_label.c | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/kernel/jump_label.c b/kernel/jump_label.c index d9c822bbffb8..3218fa5688b9 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -530,6 +530,45 @@ void __init jump_label_init(void) cpus_read_unlock(); } +static inline bool static_key_sealed(struct static_key *key) +{ + return (key->type & JUMP_TYPE_LINKED) && !(key->type & ~JUMP_TYPE_MASK); +} + +static inline void static_key_seal(struct static_key *key) +{ + unsigned long type = key->type & JUMP_TYPE_TRUE; + key->type = JUMP_TYPE_LINKED | type; +} + +void jump_label_init_ro(void) +{ + struct jump_entry *iter_start = __start___jump_table; + struct jump_entry *iter_stop = __stop___jump_table; + struct jump_entry *iter; + + if (WARN_ON_ONCE(!static_key_initialized)) + return; + + cpus_read_lock(); + jump_label_lock(); + + for (iter = iter_start; iter < iter_stop; iter++) { + struct static_key *iterk = jump_entry_key(iter); + + if (!is_kernel_ro_after_init((unsigned long)iterk)) + continue; + + if (static_key_sealed(iterk)) + continue; + + static_key_seal(iterk); + } + + jump_label_unlock(); + cpus_read_unlock(); +} + #ifdef CONFIG_MODULES enum jump_label_type jump_label_init_type(struct jump_entry *entry) @@ -650,6 +689,15 @@ static int jump_label_add_module(struct module *mod) static_key_set_entries(key, iter); continue; } + + /* + * If the key was sealed at init, then there's no need to keep a + * reference to its module entries - just patch them now and be + * done with it. + */ + if (static_key_sealed(key)) + goto do_poke; + jlm = kzalloc(sizeof(struct static_key_mod), GFP_KERNEL); if (!jlm) return -ENOMEM; @@ -675,6 +723,7 @@ static int jump_label_add_module(struct module *mod) static_key_set_linked(key); /* Only update if we've changed from our initial state */ +do_poke: if (jump_label_type(iter) != jump_label_init_type(iter)) __jump_label_update(key, iter, iter_stop, true); } @@ -699,6 +748,10 @@ static void jump_label_del_module(struct module *mod) if (within_module((unsigned long)key, mod)) continue; + /* No @jlm allocated because key was sealed at init. */ + if (static_key_sealed(key)) + continue; + /* No memory during module load */ if (WARN_ON(!static_key_linked(key))) continue; |