Merge branch 'topic/ppc-kvm' into next

Merge the DAWR series, which touches arch code and KVM code and may need
to be merged into the kvm-ppc tree.

Author: mpe

arch/powerpc/include/asm/cputable.h

@@ -464,9 +464,8 @@ static inline void cpu_feature_keys_init(void) { }
 	    CPU_FTR_DSCR | CPU_FTR_SAO  | \
 	    CPU_FTR_STCX_CHECKS_ADDRESS | CPU_FTR_POPCNTB | CPU_FTR_POPCNTD | \
 	    CPU_FTR_CFAR | CPU_FTR_HVMODE | CPU_FTR_VMX_COPY | \
-	    CPU_FTR_DBELL | CPU_FTR_HAS_PPR | CPU_FTR_DAWR | \
-	    CPU_FTR_ARCH_207S | CPU_FTR_TM_COMP | CPU_FTR_ARCH_300 | \
-	    CPU_FTR_PKEY)
+	    CPU_FTR_DBELL | CPU_FTR_HAS_PPR | CPU_FTR_ARCH_207S | \
+	    CPU_FTR_TM_COMP | CPU_FTR_ARCH_300 | CPU_FTR_PKEY)
 #define CPU_FTRS_POWER9_DD1 ((CPU_FTRS_POWER9 | CPU_FTR_POWER9_DD1) & \
 			     (~CPU_FTR_SAO))
 #define CPU_FTRS_POWER9_DD2_0 CPU_FTRS_POWER9

arch/powerpc/include/asm/debug.h

@@ -47,6 +47,7 @@ static inline int debugger_fault_handler(struct pt_regs *regs) { return 0; }
 
 void set_breakpoint(struct arch_hw_breakpoint *brk);
 void __set_breakpoint(struct arch_hw_breakpoint *brk);
+bool ppc_breakpoint_available(void);
 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 extern void do_send_trap(struct pt_regs *regs, unsigned long address,
 			 unsigned long error_code, int brkpt);

arch/powerpc/include/asm/hvcall.h

@@ -88,6 +88,7 @@
 #define H_P8		-61
 #define H_P9		-62
 #define H_TOO_BIG	-64
+#define H_UNSUPPORTED	-67
 #define H_OVERLAP	-68
 #define H_INTERRUPT	-69
 #define H_BAD_DATA	-70

arch/powerpc/kernel/dt_cpu_ftrs.c

@@ -713,6 +713,9 @@ static __init void cpufeatures_cpu_quirks(void)
 	else if ((version & 0xffffefff) == 0x004e0202)
 		cur_cpu_spec->cpu_features |= CPU_FTR_P9_TM_HV_ASSIST |
 			CPU_FTR_P9_TM_XER_SO_BUG;
+
+	if ((version & 0xffff0000) == 0x004e0000)
+		cur_cpu_spec->cpu_features &= ~(CPU_FTR_DAWR);
 }
 
 static void __init cpufeatures_setup_finished(void)

arch/powerpc/kernel/hw_breakpoint.c

@@ -33,6 +33,7 @@
 #include <asm/hw_breakpoint.h>
 #include <asm/processor.h>
 #include <asm/sstep.h>
+#include <asm/debug.h>
 #include <linux/uaccess.h>
 
 /*
@@ -171,6 +172,8 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp)
 	 * HW_BREAKPOINT_ALIGN by rounding off to the lower address, the
 	 * 'symbolsize' should satisfy the check below.
 	 */
+	if (!ppc_breakpoint_available())
+		return -ENODEV;
 	length_max = 8; /* DABR */
 	if (cpu_has_feature(CPU_FTR_DAWR)) {
 		length_max = 512 ; /* 64 doublewords */

arch/powerpc/kernel/process.c

@@ -827,6 +827,18 @@ void set_breakpoint(struct arch_hw_breakpoint *brk)
 	preempt_enable();
 }
 
+/* Check if we have DAWR or DABR hardware */
+bool ppc_breakpoint_available(void)
+{
+	if (cpu_has_feature(CPU_FTR_DAWR))
+		return true; /* POWER8 DAWR */
+	if (cpu_has_feature(CPU_FTR_ARCH_207S))
+		return false; /* POWER9 with DAWR disabled */
+	/* DABR: Everything but POWER8 and POWER9 */
+	return true;
+}
+EXPORT_SYMBOL_GPL(ppc_breakpoint_available);
+
 #ifdef CONFIG_PPC64
 DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array);
 #endif

arch/powerpc/kernel/ptrace.c

@@ -41,6 +41,7 @@
 #include <asm/switch_to.h>
 #include <asm/tm.h>
 #include <asm/asm-prototypes.h>
+#include <asm/debug.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/syscalls.h>
@@ -2378,6 +2379,7 @@ static int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
 	struct perf_event_attr attr;
 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
 #ifndef CONFIG_PPC_ADV_DEBUG_REGS
+	bool set_bp = true;
 	struct arch_hw_breakpoint hw_brk;
 #endif
 
@@ -2411,9 +2413,10 @@ static int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
 	hw_brk.address = data & (~HW_BRK_TYPE_DABR);
 	hw_brk.type = (data & HW_BRK_TYPE_DABR) | HW_BRK_TYPE_PRIV_ALL;
 	hw_brk.len = 8;
+	set_bp = (data) && (hw_brk.type & HW_BRK_TYPE_RDWR);
 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 	bp = thread->ptrace_bps[0];
-	if ((!data) || !(hw_brk.type & HW_BRK_TYPE_RDWR)) {
+	if (!set_bp) {
 		if (bp) {
 			unregister_hw_breakpoint(bp);
 			thread->ptrace_bps[0] = NULL;
@@ -2450,6 +2453,9 @@ static int ptrace_set_debugreg(struct task_struct *task, unsigned long addr,
 		return PTR_ERR(bp);
 	}
 
+#else /* !CONFIG_HAVE_HW_BREAKPOINT */
+	if (set_bp && (!ppc_breakpoint_available()))
+		return -ENODEV;
 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
 	task->thread.hw_brk = hw_brk;
 #else /* CONFIG_PPC_ADV_DEBUG_REGS */
@@ -2904,6 +2910,9 @@ static long ppc_set_hwdebug(struct task_struct *child,
 	if (child->thread.hw_brk.address)
 		return -ENOSPC;
 
+	if (!ppc_breakpoint_available())
+		return -ENODEV;
+
 	child->thread.hw_brk = brk;
 
 	return 1;
@@ -3052,7 +3061,10 @@ long arch_ptrace(struct task_struct *child, long request,
 #endif
 #else /* !CONFIG_PPC_ADV_DEBUG_REGS */
 		dbginfo.num_instruction_bps = 0;
-		dbginfo.num_data_bps = 1;
+		if (ppc_breakpoint_available())
+			dbginfo.num_data_bps = 1;
+		else
+			dbginfo.num_data_bps = 0;
 		dbginfo.num_condition_regs = 0;
 #ifdef CONFIG_PPC64
 		dbginfo.data_bp_alignment = 8;

arch/powerpc/kvm/book3s_hv.c

@@ -741,6 +741,8 @@ static int kvmppc_h_set_mode(struct kvm_vcpu *vcpu, unsigned long mflags,
 	case H_SET_MODE_RESOURCE_SET_DAWR:
 		if (!kvmppc_power8_compatible(vcpu))
 			return H_P2;
+		if (!ppc_breakpoint_available())
+			return H_P2;
 		if (mflags)
 			return H_UNSUPPORTED_FLAG_START;
 		if (value2 & DABRX_HYP)

arch/powerpc/kvm/book3s_hv_rmhandlers.S

@@ -892,8 +892,14 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S)
 	ld	r6, VCPU_DAWRX(r4)
 	ld	r7, VCPU_CIABR(r4)
 	ld	r8, VCPU_TAR(r4)
+	/*
+	 * Handle broken DAWR case by not writing it. This means we
+	 * can still store the DAWR register for migration.
+	 */
+BEGIN_FTR_SECTION
 	mtspr	SPRN_DAWR, r5
 	mtspr	SPRN_DAWRX, r6
+END_FTR_SECTION_IFSET(CPU_FTR_DAWR)
 	mtspr	SPRN_CIABR, r7
 	mtspr	SPRN_TAR, r8
 	ld	r5, VCPU_IC(r4)
@@ -1855,6 +1861,10 @@ BEGIN_FTR_SECTION
 	ld	r6, STACK_SLOT_DAWR(r1)
 	ld	r7, STACK_SLOT_DAWRX(r1)
 	mtspr	SPRN_CIABR, r5
+	/*
+	 * If the DAWR doesn't work, it's ok to write these here as
+	 * this value should always be zero
+	*/
 	mtspr	SPRN_DAWR, r6
 	mtspr	SPRN_DAWRX, r7
 END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
@@ -2563,8 +2573,14 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
 	li	r3,0
 	blr
 
+2:
+BEGIN_FTR_SECTION
+	/* POWER9 with disabled DAWR */
+	li	r3, H_UNSUPPORTED
+	blr
+END_FTR_SECTION_IFCLR(CPU_FTR_DAWR)
 	/* Emulate H_SET_DABR/X on P8 for the sake of compat mode guests */
-2:	rlwimi	r5, r4, 5, DAWRX_DR | DAWRX_DW
+	rlwimi	r5, r4, 5, DAWRX_DR | DAWRX_DW
 	rlwimi	r5, r4, 2, DAWRX_WT
 	clrrdi	r4, r4, 3
 	std	r4, VCPU_DAWR(r3)

arch/powerpc/xmon/xmon.c

@@ -1302,6 +1302,10 @@ bpt_cmds(void)
 	static const char badaddr[] = "Only kernel addresses are permitted for breakpoints\n";
 	int mode;
 	case 'd':	/* bd - hardware data breakpoint */
+		if (!ppc_breakpoint_available()) {
+			printf("Hardware data breakpoint not supported on this cpu\n");
+			break;
+		}
 		mode = 7;
 		cmd = inchar();
 		if (cmd == 'r')