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- Improve code generation in ACPI's global lock's acquisition function

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Merge tag 'x86_acpi_for_v6.4_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 ACPI update from Borislav Petkov:

 - Improve code generation in ACPI's global lock's acquisition function

* tag 'x86_acpi_for_v6.4_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/ACPI/boot: Improve __acpi_acquire_global_lock
This commit is contained in:
Linus Torvalds 2023-04-25 10:05:00 -07:00
commit 1699dbebf3
1 changed files with 8 additions and 3 deletions
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11
arch/x86/kernel/acpi/boot.c
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@ -1858,13 +1858,18 @@ early_param("acpi_sci", setup_acpi_sci);
int __acpi_acquire_global_lock(unsigned int *lock) int __acpi_acquire_global_lock(unsigned int *lock)
{ {
unsigned int old, new; unsigned int old, new, val;
old = READ_ONCE(*lock); old = READ_ONCE(*lock);
do { do {
new = (((old & ~0x3) + 2) + ((old >> 1) & 0x1)); val = (old >> 1) & 0x1;
new = (old & ~0x3) + 2 + val;
} while (!try_cmpxchg(lock, &old, new)); } while (!try_cmpxchg(lock, &old, new));
return ((new & 0x3) < 3) ? -1 : 0;
if (val)
return 0;
return -1;
} }
int __acpi_release_global_lock(unsigned int *lock) int __acpi_release_global_lock(unsigned int *lock)