Commit 49a7d46a authored Jul 24, 2020 by Nicholas Piggin Committed by Michael Ellerman Jul 27, 2020

powerpc: Implement smp_cond_load_relaxed()



This implements smp_cond_load_relaxed() with the slowpath busy loop
using the preferred SMT priority pattern.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Waiman Long <longman@redhat.com>
[mpe: Make it 64-bit only to fix build errors on 32-bit]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200724131423.1362108-7-npiggin@gmail.com

parent 2f6560e6

arch/powerpc/include/asm/barrier.h

+16 −0

Original line number	Diff line number	Diff line
		@@ -80,6 +80,22 @@ do { \
		___p1; \
		})

		#ifdef CONFIG_PPC64
		#define smp_cond_load_relaxed(ptr, cond_expr) ({ \
		typeof(ptr) __PTR = (ptr); \
		__unqual_scalar_typeof(*ptr) VAL; \
		VAL = READ_ONCE(*__PTR); \
		if (unlikely(!(cond_expr))) { \
		spin_begin(); \
		do { \
		VAL = READ_ONCE(*__PTR); \
		} while (!(cond_expr)); \
		spin_end(); \
		} \
		(typeof(*ptr))VAL; \
		})
		#endif

		#ifdef CONFIG_PPC_BOOK3S_64
		#define NOSPEC_BARRIER_SLOT nop
		#elif defined(CONFIG_PPC_FSL_BOOK3E)

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