powerpc fixes for 4.10 #4

Four fixes from Ben:
 
  - Userspace was semi-randomly segfaulting on radix due to us incorrectly
    handling a fault triggered by autonuma, caused by a patch we merged earlier
    in v4.10 to prevent the kernel executing userspace.
  - We weren't marking host IPIs properly for KVM in the OPAL ICP backend.
  - The ERAT flushing on radix was missing an isync and was incorrectly marked
    as DD1 only.
  - The powernv CPU hotplug code was missing a wakeup type and failing to flush
    the interrupt correctly when using OPAL ICP.
 
 Thanks to:
   Benjamin Herrenschmidt.
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Merge tag 'powerpc-4.10-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc fixes friom Michael Ellerman:
 "Apologies for the late pull request, but Ben has been busy finding bugs.

   - Userspace was semi-randomly segfaulting on radix due to us
     incorrectly handling a fault triggered by autonuma, caused by a
     patch we merged earlier in v4.10 to prevent the kernel executing
     userspace.

   - We weren't marking host IPIs properly for KVM in the OPAL ICP
     backend.

   - The ERAT flushing on radix was missing an isync and was incorrectly
     marked as DD1 only.

   - The powernv CPU hotplug code was missing a wakeup type and failing
     to flush the interrupt correctly when using OPAL ICP

  Thanks to Benjamin Herrenschmidt"

* tag 'powerpc-4.10-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/powernv: Properly set "host-ipi" on IPIs
  powerpc/powernv: Fix CPU hotplug to handle waking on HVI
  powerpc/mm/radix: Update ERAT flushes when invalidating TLB
  powerpc/mm: Fix spurrious segfaults on radix with autonuma

arch/powerpc/include/asm/reg.h

@@ -649,9 +649,10 @@
 #define   SRR1_ISI_N_OR_G	0x10000000 /* ISI: Access is no-exec or G */
 #define   SRR1_ISI_PROT		0x08000000 /* ISI: Other protection fault */
 #define   SRR1_WAKEMASK		0x00380000 /* reason for wakeup */
-#define   SRR1_WAKEMASK_P8	0x003c0000 /* reason for wakeup on POWER8 */
+#define   SRR1_WAKEMASK_P8	0x003c0000 /* reason for wakeup on POWER8 and 9 */
 #define   SRR1_WAKESYSERR	0x00300000 /* System error */
 #define   SRR1_WAKEEE		0x00200000 /* External interrupt */
+#define   SRR1_WAKEHVI		0x00240000 /* Hypervisor Virtualization Interrupt (P9) */
 #define   SRR1_WAKEMT		0x00280000 /* mtctrl */
 #define	  SRR1_WAKEHMI		0x00280000 /* Hypervisor maintenance */
 #define   SRR1_WAKEDEC		0x00180000 /* Decrementer interrupt */

arch/powerpc/include/asm/xics.h

@@ -44,6 +44,7 @@ static inline int icp_hv_init(void) { return -ENODEV; }
 
 #ifdef CONFIG_PPC_POWERNV
 extern int icp_opal_init(void);
+extern void icp_opal_flush_interrupt(void);
 #else
 static inline int icp_opal_init(void) { return -ENODEV; }
 #endif

arch/powerpc/mm/fault.c

@@ -253,8 +253,11 @@ int do_page_fault(struct pt_regs *regs, unsigned long address,
 	if (unlikely(debugger_fault_handler(regs)))
 		goto bail;
 
-	/* On a kernel SLB miss we can only check for a valid exception entry */
-	if (!user_mode(regs) && (address >= TASK_SIZE)) {
+	/*
+	 * The kernel should never take an execute fault nor should it
+	 * take a page fault to a kernel address.
+	 */
+	if (!user_mode(regs) && (is_exec || (address >= TASK_SIZE))) {
 		rc = SIGSEGV;
 		goto bail;
 	}
@@ -390,20 +393,6 @@ int do_page_fault(struct pt_regs *regs, unsigned long address,
 #endif /* CONFIG_8xx */
 
 	if (is_exec) {
-		/*
-		 * An execution fault + no execute ?
-		 *
-		 * On CPUs that don't have CPU_FTR_COHERENT_ICACHE we
-		 * deliberately create NX mappings, and use the fault to do the
-		 * cache flush. This is usually handled in hash_page_do_lazy_icache()
-		 * but we could end up here if that races with a concurrent PTE
-		 * update. In that case we need to fall through here to the VMA
-		 * check below.
-		 */
-		if (cpu_has_feature(CPU_FTR_COHERENT_ICACHE) &&
-			(regs->msr & SRR1_ISI_N_OR_G))
-			goto bad_area;
-
 		/*
 		 * Allow execution from readable areas if the MMU does not
 		 * provide separate controls over reading and executing.

arch/powerpc/mm/tlb-radix.c

@@ -50,9 +50,7 @@ static inline void _tlbiel_pid(unsigned long pid, unsigned long ric)
 	for (set = 0; set < POWER9_TLB_SETS_RADIX ; set++) {
 		__tlbiel_pid(pid, set, ric);
 	}
-	if (cpu_has_feature(CPU_FTR_POWER9_DD1))
-		asm volatile(PPC_INVALIDATE_ERAT : : :"memory");
-	return;
+	asm volatile(PPC_INVALIDATE_ERAT "; isync" : : :"memory");
 }
 
 static inline void _tlbie_pid(unsigned long pid, unsigned long ric)
@@ -85,8 +83,6 @@ static inline void _tlbiel_va(unsigned long va, unsigned long pid,
 	asm volatile(PPC_TLBIEL(%0, %4, %3, %2, %1)
 		     : : "r"(rb), "i"(r), "i"(prs), "i"(ric), "r"(rs) : "memory");
 	asm volatile("ptesync": : :"memory");
-	if (cpu_has_feature(CPU_FTR_POWER9_DD1))
-		asm volatile(PPC_INVALIDATE_ERAT : : :"memory");
 }
 
 static inline void _tlbie_va(unsigned long va, unsigned long pid,

arch/powerpc/platforms/powernv/smp.c

@@ -155,8 +155,10 @@ static void pnv_smp_cpu_kill_self(void)
 		wmask = SRR1_WAKEMASK_P8;
 
 	idle_states = pnv_get_supported_cpuidle_states();
+
 	/* We don't want to take decrementer interrupts while we are offline,
-	 * so clear LPCR:PECE1. We keep PECE2 enabled.
+	 * so clear LPCR:PECE1. We keep PECE2 (and LPCR_PECE_HVEE on P9)
+	 * enabled as to let IPIs in.
 	 */
 	mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) & ~(u64)LPCR_PECE1);
 
@@ -206,8 +208,12 @@ static void pnv_smp_cpu_kill_self(void)
 		 * contains 0.
 		 */
 		if (((srr1 & wmask) == SRR1_WAKEEE) ||
+		    ((srr1 & wmask) == SRR1_WAKEHVI) ||
 		    (local_paca->irq_happened & PACA_IRQ_EE)) {
-			icp_native_flush_interrupt();
+			if (cpu_has_feature(CPU_FTR_ARCH_300))
+				icp_opal_flush_interrupt();
+			else
+				icp_native_flush_interrupt();
 		} else if ((srr1 & wmask) == SRR1_WAKEHDBELL) {
 			unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER);
 			asm volatile(PPC_MSGCLR(%0) : : "r" (msg));
@@ -221,6 +227,8 @@ static void pnv_smp_cpu_kill_self(void)
 		if (srr1 && !generic_check_cpu_restart(cpu))
 			DBG("CPU%d Unexpected exit while offline !\n", cpu);
 	}
+
+	/* Re-enable decrementer interrupts */
 	mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_PECE1);
 	DBG("CPU%d coming online...\n", cpu);
 }

arch/powerpc/sysdev/xics/icp-opal.c

@@ -120,18 +120,49 @@ static void icp_opal_cause_ipi(int cpu, unsigned long data)
 {
 	int hw_cpu = get_hard_smp_processor_id(cpu);
 
+	kvmppc_set_host_ipi(cpu, 1);
 	opal_int_set_mfrr(hw_cpu, IPI_PRIORITY);
 }
 
 static irqreturn_t icp_opal_ipi_action(int irq, void *dev_id)
 {
-	int hw_cpu = hard_smp_processor_id();
+	int cpu = smp_processor_id();
 
-	opal_int_set_mfrr(hw_cpu, 0xff);
+	kvmppc_set_host_ipi(cpu, 0);
+	opal_int_set_mfrr(get_hard_smp_processor_id(cpu), 0xff);
 
 	return smp_ipi_demux();
 }
 
+/*
+ * Called when an interrupt is received on an off-line CPU to
+ * clear the interrupt, so that the CPU can go back to nap mode.
+ */
+void icp_opal_flush_interrupt(void)
+{
+	unsigned int xirr;
+	unsigned int vec;
+
+	do {
+		xirr = icp_opal_get_xirr();
+		vec = xirr & 0x00ffffff;
+		if (vec == XICS_IRQ_SPURIOUS)
+			break;
+		if (vec == XICS_IPI) {
+			/* Clear pending IPI */
+			int cpu = smp_processor_id();
+			kvmppc_set_host_ipi(cpu, 0);
+			opal_int_set_mfrr(get_hard_smp_processor_id(cpu), 0xff);
+		} else {
+			pr_err("XICS: hw interrupt 0x%x to offline cpu, "
+			       "disabling\n", vec);
+			xics_mask_unknown_vec(vec);
+		}
+
+		/* EOI the interrupt */
+	} while (opal_int_eoi(xirr) > 0);
+}
+
 #endif /* CONFIG_SMP */
 
 static const struct icp_ops icp_opal_ops = {