powerpc fixes for 4.14 #6

A fix to the handling of misaligned paste instructions (P9 only), where a change
 to a #define has caused the check for the instruction to always fail.
 
 The preempt handling was unbalanced in the radix THP flush (P9 only). Though we
 don't generally use preempt we want to keep it working as much as possible.
 
 Two fixes for IMC (P9 only), one when booting with restricted number of CPUs and
 one in the error handling when initialisation fails due to firmware etc.
 
 A revert to fix function_graph on big endian machines, and then a rework of the
 reverted patch to fix kprobes blacklist handling on big endian machines.
 
 Thanks to:
   Anju T Sudhakar, Guilherme G. Piccoli, Madhavan Srinivasan, Naveen N. Rao,
   Nicholas Piggin, Paul Mackerras.
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Merge tag 'powerpc-4.14-6' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc fixes from Michael Ellerman:
 "Some more powerpc fixes for 4.14.

  This is bigger than I like to send at rc7, but that's at least partly
  because I didn't send any fixes last week. If it wasn't for the IMC
  driver, which is new and getting heavy testing, the diffstat would
  look a bit better. I've also added ftrace on big endian to my test
  suite, so we shouldn't break that again in future.

   - A fix to the handling of misaligned paste instructions (P9 only),
     where a change to a #define has caused the check for the
     instruction to always fail.

   - The preempt handling was unbalanced in the radix THP flush (P9
     only). Though we don't generally use preempt we want to keep it
     working as much as possible.

   - Two fixes for IMC (P9 only), one when booting with restricted
     number of CPUs and one in the error handling when initialisation
     fails due to firmware etc.

   - A revert to fix function_graph on big endian machines, and then a
     rework of the reverted patch to fix kprobes blacklist handling on
     big endian machines.

  Thanks to: Anju T Sudhakar, Guilherme G. Piccoli, Madhavan Srinivasan,
  Naveen N. Rao, Nicholas Piggin, Paul Mackerras"

* tag 'powerpc-4.14-6' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/perf: Fix core-imc hotplug callback failure during imc initialization
  powerpc/kprobes: Dereference function pointers only if the address does not belong to kernel text
  Revert "powerpc64/elfv1: Only dereference function descriptor for non-text symbols"
  powerpc/64s/radix: Fix preempt imbalance in TLB flush
  powerpc: Fix check for copy/paste instructions in alignment handler
  powerpc/perf: Fix IMC allocation routine

arch/powerpc/include/asm/code-patching.h

@@ -83,16 +83,8 @@ static inline unsigned long ppc_function_entry(void *func)
 	 * On PPC64 ABIv1 the function pointer actually points to the
 	 * function's descriptor. The first entry in the descriptor is the
 	 * address of the function text.
-	 *
-	 * However, we may also receive pointer to an assembly symbol. To
-	 * detect that, we first check if the function pointer we receive
-	 * already points to kernel/module text and we only dereference it
-	 * if it doesn't.
 	 */
-	if (kernel_text_address((unsigned long)func))
-		return (unsigned long)func;
-	else
-		return ((func_descr_t *)func)->entry;
+	return ((func_descr_t *)func)->entry;
 #else
 	return (unsigned long)func;
 #endif

arch/powerpc/kernel/align.c

@@ -332,7 +332,7 @@ int fix_alignment(struct pt_regs *regs)
 	 * when pasting to a co-processor. Furthermore, paste_last is the
 	 * synchronisation point for preceding copy/paste sequences.
 	 */
-	if ((instr & 0xfc0006fe) == PPC_INST_COPY)
+	if ((instr & 0xfc0006fe) == (PPC_INST_COPY & 0xfc0006fe))
 		return -EIO;
 
 	r = analyse_instr(&op, regs, instr);

arch/powerpc/kernel/kprobes.c

@@ -600,7 +600,12 @@ NOKPROBE_SYMBOL(kprobe_fault_handler);
 
 unsigned long arch_deref_entry_point(void *entry)
 {
-	return ppc_global_function_entry(entry);
+#ifdef PPC64_ELF_ABI_v1
+	if (!kernel_text_address((unsigned long)entry))
+		return ppc_global_function_entry(entry);
+	else
+#endif
+		return (unsigned long)entry;
 }
 NOKPROBE_SYMBOL(arch_deref_entry_point);
 

arch/powerpc/mm/tlb-radix.c

@@ -360,12 +360,14 @@ void radix__flush_tlb_collapsed_pmd(struct mm_struct *mm, unsigned long addr)
 
 
 	pid = mm ? mm->context.id : 0;
+	preempt_disable();
 	if (unlikely(pid == MMU_NO_CONTEXT))
 		goto no_context;
 
 	/* 4k page size, just blow the world */
 	if (PAGE_SIZE == 0x1000) {
 		radix__flush_all_mm(mm);
+		preempt_enable();
 		return;
 	}
 

arch/powerpc/perf/imc-pmu.c

@@ -607,6 +607,20 @@ static int ppc_core_imc_cpu_offline(unsigned int cpu)
 	if (!cpumask_test_and_clear_cpu(cpu, &core_imc_cpumask))
 		return 0;
 
+	/*
+	 * Check whether core_imc is registered. We could end up here
+	 * if the cpuhotplug callback registration fails. i.e, callback
+	 * invokes the offline path for all sucessfully registered cpus.
+	 * At this stage, core_imc pmu will not be registered and we
+	 * should return here.
+	 *
+	 * We return with a zero since this is not an offline failure.
+	 * And cpuhp_setup_state() returns the actual failure reason
+	 * to the caller, which inturn will call the cleanup routine.
+	 */
+	if (!core_imc_pmu->pmu.event_init)
+		return 0;
+
 	/* Find any online cpu in that core except the current "cpu" */
 	ncpu = cpumask_any_but(cpu_sibling_mask(cpu), cpu);
 
@@ -1104,7 +1118,7 @@ static int init_nest_pmu_ref(void)
 
 static void cleanup_all_core_imc_memory(void)
 {
-	int i, nr_cores = num_present_cpus() / threads_per_core;
+	int i, nr_cores = DIV_ROUND_UP(num_present_cpus(), threads_per_core);
 	struct imc_mem_info *ptr = core_imc_pmu->mem_info;
 	int size = core_imc_pmu->counter_mem_size;
 
@@ -1212,7 +1226,7 @@ static int imc_mem_init(struct imc_pmu *pmu_ptr, struct device_node *parent,
 		if (!pmu_ptr->pmu.name)
 			return -ENOMEM;
 
-		nr_cores = num_present_cpus() / threads_per_core;
+		nr_cores = DIV_ROUND_UP(num_present_cpus(), threads_per_core);
 		pmu_ptr->mem_info = kcalloc(nr_cores, sizeof(struct imc_mem_info),
 								GFP_KERNEL);