The LDCW barriers in the light-weight system (LWS) calls in syscall.S can be removed. Ordered stores can be used to provide the necessary release semantics. This saves an instruction that is relatively expensive. Signed-off-by: Dave Anglin <dave.anglin@xxxxxxxx> --- diff --git a/arch/parisc/kernel/syscall.S b/arch/parisc/kernel/syscall.S index f05c9d5b6b9e..069c7c93d16b 100644 --- a/arch/parisc/kernel/syscall.S +++ b/arch/parisc/kernel/syscall.S @@ -640,11 +640,7 @@ cas_action: sub,<> %r28, %r25, %r0 2: stw %r24, 0(%r26) /* Free lock */ -#ifdef CONFIG_SMP -98: LDCW 0(%sr2,%r20), %r1 /* Barrier */ -99: ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP) -#endif - stw %r20, 0(%sr2,%r20) + stw,ma %r20, 0(%sr2,%r20) /* Ordered store */ #if ENABLE_LWS_DEBUG /* Clear thread register indicator */ stw %r0, 4(%sr2,%r20) @@ -658,11 +654,7 @@ cas_action: 3: /* Error occurred on load or store */ /* Free lock */ -#ifdef CONFIG_SMP -98: LDCW 0(%sr2,%r20), %r1 /* Barrier */ -99: ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP) -#endif - stw %r20, 0(%sr2,%r20) + stw,ma %r20, 0(%sr2,%r20) /* Ordered store */ #if ENABLE_LWS_DEBUG stw %r0, 4(%sr2,%r20) #endif @@ -863,11 +855,7 @@ cas2_action: cas2_end: /* Free lock */ -#ifdef CONFIG_SMP -98: LDCW 0(%sr2,%r20), %r1 /* Barrier */ -99: ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP) -#endif - stw %r20, 0(%sr2,%r20) + stw,ma %r20, 0(%sr2,%r20) /* Ordered store */ /* Enable interrupts */ ssm PSW_SM_I, %r0 /* Return to userspace, set no error */ @@ -876,12 +864,7 @@ cas2_end: 22: /* Error occurred on load or store */ - /* Free lock */ -#ifdef CONFIG_SMP -98: LDCW 0(%sr2,%r20), %r1 /* Barrier */ -99: ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP) -#endif - stw %r20, 0(%sr2,%r20) + stw,ma %r20, 0(%sr2,%r20) /* Ordered store */ ssm PSW_SM_I, %r0 ldo 1(%r0),%r28 b lws_exit
