There are only a couple of instructions that can function as a memory barrier on parisc. Currently, we use the sync instruction as a memory barrier when releasing a spinlock. However, the ldcw instruction is a better barrier when we have a handy memory location since it operates in the cache on coherent machines. This patch updates the spinlock release code to use ldcw. I also changed the "stw,ma" instructions to "stw" instructions as it is not an adequate barrier. Signed-off-by: John David Anglin <dave.anglin@xxxxxxxx> diff --git a/arch/parisc/include/asm/spinlock.h b/arch/parisc/include/asm/spinlock.h index 8a63515f03bf..197d2247e4db 100644 --- a/arch/parisc/include/asm/spinlock.h +++ b/arch/parisc/include/asm/spinlock.h @@ -37,7 +37,11 @@ static inline void arch_spin_unlock(arch_spinlock_t *x) volatile unsigned int *a; a = __ldcw_align(x); +#ifdef CONFIG_SMP + (void) __ldcw(a); +#else mb(); +#endif *a = 1; } diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S index d5eb19efa65b..a1fc04570ade 100644 --- a/arch/parisc/kernel/entry.S +++ b/arch/parisc/kernel/entry.S @@ -471,8 +467,9 @@ nop LDREG 0(\ptp),\pte bb,<,n \pte,_PAGE_PRESENT_BIT,3f + LDCW 0(\tmp),\tmp1 b \fault - stw,ma \spc,0(\tmp) + stw \spc,0(\tmp) 99: ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP) #endif 2: LDREG 0(\ptp),\pte @@ -481,20 +478,22 @@ .endm /* Release pa_tlb_lock lock without reloading lock address. */ - .macro tlb_unlock0 spc,tmp + .macro tlb_unlock0 spc,tmp,tmp1 #ifdef CONFIG_SMP 98: or,COND(=) %r0,\spc,%r0 - stw,ma \spc,0(\tmp) + LDCW 0(\tmp),\tmp1 + or,COND(=) %r0,\spc,%r0 + stw \spc,0(\tmp) 99: ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP) #endif .endm /* Release pa_tlb_lock lock. */ - .macro tlb_unlock1 spc,tmp + .macro tlb_unlock1 spc,tmp,tmp1 #ifdef CONFIG_SMP 98: load_pa_tlb_lock \tmp 99: ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP) - tlb_unlock0 \spc,\tmp + tlb_unlock0 \spc,\tmp,\tmp1 #endif .endm @@ -1177,7 +1176,7 @@ dtlb_miss_20w: idtlbt pte,prot - tlb_unlock1 spc,t0 + tlb_unlock1 spc,t0,t1 rfir nop @@ -1203,7 +1202,7 @@ nadtlb_miss_20w: idtlbt pte,prot - tlb_unlock1 spc,t0 + tlb_unlock1 spc,t0,t1 rfir nop @@ -1237,7 +1236,7 @@ dtlb_miss_11: mtsp t1, %sr1 /* Restore sr1 */ - tlb_unlock1 spc,t0 + tlb_unlock1 spc,t0,t1 rfir nop @@ -1270,7 +1269,7 @@ nadtlb_miss_11: mtsp t1, %sr1 /* Restore sr1 */ - tlb_unlock1 spc,t0 + tlb_unlock1 spc,t0,t1 rfir nop @@ -1299,7 +1298,7 @@ dtlb_miss_20: idtlbt pte,prot - tlb_unlock1 spc,t0 + tlb_unlock1 spc,t0,t1 rfir nop @@ -1327,7 +1326,7 @@ nadtlb_miss_20: idtlbt pte,prot - tlb_unlock1 spc,t0 + tlb_unlock1 spc,t0,t1 rfir nop @@ -1434,7 +1433,7 @@ itlb_miss_20w: iitlbt pte,prot - tlb_unlock1 spc,t0 + tlb_unlock1 spc,t0,t1 rfir nop @@ -1458,7 +1457,7 @@ naitlb_miss_20w: iitlbt pte,prot - tlb_unlock1 spc,t0 + tlb_unlock1 spc,t0,t1 rfir nop @@ -1492,7 +1491,7 @@ itlb_miss_11: mtsp t1, %sr1 /* Restore sr1 */ - tlb_unlock1 spc,t0 + tlb_unlock1 spc,t0,t1 rfir nop @@ -1516,7 +1515,7 @@ naitlb_miss_11: mtsp t1, %sr1 /* Restore sr1 */ - tlb_unlock1 spc,t0 + tlb_unlock1 spc,t0,t1 rfir nop @@ -1546,7 +1545,7 @@ itlb_miss_20: iitlbt pte,prot - tlb_unlock1 spc,t0 + tlb_unlock1 spc,t0,t1 rfir nop @@ -1566,7 +1565,7 @@ naitlb_miss_20: iitlbt pte,prot - tlb_unlock1 spc,t0 + tlb_unlock1 spc,t0,t1 rfir nop @@ -1596,7 +1595,7 @@ dbit_trap_20w: idtlbt pte,prot - tlb_unlock0 spc,t0 + tlb_unlock0 spc,t0,t1 rfir nop #else @@ -1622,7 +1621,7 @@ dbit_trap_11: mtsp t1, %sr1 /* Restore sr1 */ - tlb_unlock0 spc,t0 + tlb_unlock0 spc,t0,t1 rfir nop @@ -1642,7 +1641,7 @@ dbit_trap_20: idtlbt pte,prot - tlb_unlock0 spc,t0 + tlb_unlock0 spc,t0,t1 rfir nop #endif diff --git a/arch/parisc/kernel/syscall.S b/arch/parisc/kernel/syscall.S index 4f77bd9be66b..e2b4c8d81275 100644 --- a/arch/parisc/kernel/syscall.S +++ b/arch/parisc/kernel/syscall.S @@ -640,7 +640,9 @@ cas_action: sub,<> %r28, %r25, %r0 2: stw %r24, 0(%r26) /* Free lock */ - sync +#ifdef CONFIG_SMP + LDCW 0(%sr2,%r20), %r1 /* Barrier */ +#endif stw %r20, 0(%sr2,%r20) #if ENABLE_LWS_DEBUG /* Clear thread register indicator */ @@ -655,7 +657,9 @@ cas_action: 3: /* Error occurred on load or store */ /* Free lock */ - sync +#ifdef CONFIG_SMP + LDCW 0(%sr2,%r20), %r1 /* Barrier */ +#endif stw %r20, 0(%sr2,%r20) #if ENABLE_LWS_DEBUG stw %r0, 4(%sr2,%r20) @@ -857,7 +861,9 @@ cas2_action: cas2_end: /* Free lock */ - sync +#ifdef CONFIG_SMP + LDCW 0(%sr2,%r20), %r1 /* Barrier */ +#endif stw %r20, 0(%sr2,%r20) /* Enable interrupts */ ssm PSW_SM_I, %r0 @@ -868,7 +874,9 @@ cas2_end: 22: /* Error occurred on load or store */ /* Free lock */ - sync +#ifdef CONFIG_SMP + LDCW 0(%sr2,%r20), %r1 /* Barrier */ +#endif stw %r20, 0(%sr2,%r20) ssm PSW_SM_I, %r0 ldo 1(%r0),%r28
