Commit 5753762c authored by Markos Chandras's avatar Markos Chandras
Browse files

MIPS: asm: spinlock: Replace "sub" instruction with "addiu" 



"sub $reg, imm" is not a real MIPS instruction. The assembler can
replace that with "addi $reg, -imm". However, addi has been removed
from R6, so we replace the "sub" instruction with the "addiu" one.

Signed-off-by: default avatarMarkos Chandras <markos.chandras@imgtec.com>
parent 1922c356

arch/mips/include/asm/spinlock.h

+2 −5
Original line number Diff line number Diff line
@@ -254,9 +254,6 @@ static inline void arch_read_lock(arch_rwlock_t *rw) 
	smp_llsc_mb();

}



/* Note the use of sub, not subu which will make the kernel die with an

   overflow exception if we ever try to unlock an rwlock that is already

   unlocked or is being held by a writer.  */

static inline void arch_read_unlock(arch_rwlock_t *rw)

{

	unsigned int tmp;
@@ -266,7 +263,7 @@ static inline void arch_read_unlock(arch_rwlock_t *rw) 
	if (R10000_LLSC_WAR) {

		__asm__ __volatile__(

		"1:	ll	%1, %2		# arch_read_unlock	\n"

		"	sub	%1, 1					\n"

		"	addiu	%1, 1					\n"

		"	sc	%1, %0					\n"

		"	beqzl	%1, 1b					\n"

		: "=" GCC_OFF_SMALL_ASM() (rw->lock), "=&r" (tmp)
@@ -276,7 +273,7 @@ static inline void arch_read_unlock(arch_rwlock_t *rw) 
		do {

			__asm__ __volatile__(

			"1:	ll	%1, %2	# arch_read_unlock	\n"

			"	sub	%1, 1				\n"

			"	addiu	%1, -1				\n"

			"	sc	%1, %0				\n"

			: "=" GCC_OFF_SMALL_ASM() (rw->lock), "=&r" (tmp)

			: GCC_OFF_SMALL_ASM() (rw->lock)

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