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Unverified Commit 82f4f66d authored by Paul Burton's avatar Paul Burton
Browse files

MIPS: Remove open-coded cmpxchg() in set_pte() 



set_pte() contains an open coded version of cmpxchg() - it atomically
replaces the buddy pte's value if it is currently zero. Simplify the
code considerably by just using cmpxchg() instead of reinventing it.

Signed-off-by: default avatarPaul Burton <paul.burton@mips.com>
Cc: linux-mips@vger.kernel.org
parent c8790d65

arch/mips/include/asm/pgtable.h

+2 −43
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <asm/pgtable-64.h>

#endif



#include <asm/cmpxchg.h>

#include <asm/io.h>

#include <asm/pgtable-bits.h>
@@ -204,49 +205,7 @@ static inline void set_pte(pte_t *ptep, pte_t pteval) 
		 * Make sure the buddy is global too (if it's !none,

		 * it better already be global)

		 */

#ifdef CONFIG_SMP

		/*

		 * For SMP, multiple CPUs can race, so we need to do

		 * this atomically.

		 */

		unsigned long page_global = _PAGE_GLOBAL;

		unsigned long tmp;



		if (kernel_uses_llsc && R10000_LLSC_WAR) {

			__asm__ __volatile__ (

			"	.set	push				\n"

			"	.set	arch=r4000			\n"

			"	.set	noreorder			\n"

			"1:"	__LL	"%[tmp], %[buddy]		\n"

			"	bnez	%[tmp], 2f			\n"

			"	 or	%[tmp], %[tmp], %[global]	\n"

				__SC	"%[tmp], %[buddy]		\n"

			"	beqzl	%[tmp], 1b			\n"

			"	nop					\n"

			"2:						\n"

			"	.set	pop				\n"

			: [buddy] "+m" (buddy->pte), [tmp] "=&r" (tmp)

			: [global] "r" (page_global));

		} else if (kernel_uses_llsc) {

			__asm__ __volatile__ (

			"	.set	push				\n"

			"	.set	"MIPS_ISA_ARCH_LEVEL"		\n"

			"	.set	noreorder			\n"

			"1:"	__LL	"%[tmp], %[buddy]		\n"

			"	bnez	%[tmp], 2f			\n"

			"	 or	%[tmp], %[tmp], %[global]	\n"

				__SC	"%[tmp], %[buddy]		\n"

			"	beqz	%[tmp], 1b			\n"

			"	nop					\n"

			"2:						\n"

			"	.set	pop				\n"

			: [buddy] "+m" (buddy->pte), [tmp] "=&r" (tmp)

			: [global] "r" (page_global));

		}

#else /* !CONFIG_SMP */

		if (pte_none(*buddy))

			pte_val(*buddy) = pte_val(*buddy) | _PAGE_GLOBAL;

#endif /* CONFIG_SMP */

		cmpxchg(&buddy->pte, 0, _PAGE_GLOBAL);

	}

#endif

}