arch/x86: Add ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option

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The x86 architecture uses an add-to-memory instruction to implement
this_cpu_add(), which is NMI safe.  This means that the old and
more-efficient srcu_read_lock() may be used in NMI context, without
the need for srcu_read_lock_nmisafe().  Therefore, add the new Kconfig
option ARCH_HAS_NMI_SAFE_THIS_CPU_OPS to arch/x86/Kconfig, which will
cause NEED_SRCU_NMI_SAFE to be deselected, thus preserving the current
srcu_read_lock() behavior.

Link: https://lore.kernel.org/all/20220910221947.171557773@linutronix.de/

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Petr Mladek <pmladek@suse.com>
Cc: <x86@kernel.org>

...

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Paul E. McKenney 2022-09-28 11:11:18 -07:00

parent 36f65f1d15

commit 49f88c70ed

1 changed files with 1 additions and 0 deletions

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