1 files changed, 56 insertions, 6 deletions

diff --git a/arch/powerpc/mm/pgtable-radix.c b/arch/powerpc/mm/pgtable-radix.c
index 8c13e4282308..671a45d86c18 100644
--- a/arch/powerpc/mm/pgtable-radix.c
+++ b/arch/powerpc/mm/pgtable-radix.c
@@ -25,6 +25,9 @@
 
 #include <trace/events/thp.h>
 
+unsigned int mmu_pid_bits;
+unsigned int mmu_base_pid;
+
 static int native_register_process_table(unsigned long base, unsigned long pg_sz,
 					 unsigned long table_size)
 {
@@ -112,10 +115,9 @@ set_the_pte:
 }
 
 #ifdef CONFIG_STRICT_KERNEL_RWX
-void radix__mark_rodata_ro(void)
+void radix__change_memory_range(unsigned long start, unsigned long end,
+				unsigned long clear)
 {
-	unsigned long start = (unsigned long)_stext;
-	unsigned long end = (unsigned long)__init_begin;
 	unsigned long idx;
 	pgd_t *pgdp;
 	pud_t *pudp;
@@ -125,7 +127,8 @@ void radix__mark_rodata_ro(void)
 	start = ALIGN_DOWN(start, PAGE_SIZE);
 	end = PAGE_ALIGN(end); // aligns up
 
-	pr_devel("marking ro start %lx, end %lx\n", start, end);
+	pr_debug("Changing flags on range %lx-%lx removing 0x%lx\n",
+		 start, end, clear);
 
 	for (idx = start; idx < end; idx += PAGE_SIZE) {
 		pgdp = pgd_offset_k(idx);
@@ -147,11 +150,29 @@ void radix__mark_rodata_ro(void)
 		if (!ptep)
 			continue;
 update_the_pte:
-		radix__pte_update(&init_mm, idx, ptep, _PAGE_WRITE, 0, 0);
+		radix__pte_update(&init_mm, idx, ptep, clear, 0, 0);
 	}
 
 	radix__flush_tlb_kernel_range(start, end);
 }
+
+void radix__mark_rodata_ro(void)
+{
+	unsigned long start, end;
+
+	start = (unsigned long)_stext;
+	end = (unsigned long)__init_begin;
+
+	radix__change_memory_range(start, end, _PAGE_WRITE);
+}
+
+void radix__mark_initmem_nx(void)
+{
+	unsigned long start = (unsigned long)__init_begin;
+	unsigned long end = (unsigned long)__init_end;
+
+	radix__change_memory_range(start, end, _PAGE_EXEC);
+}
 #endif /* CONFIG_STRICT_KERNEL_RWX */
 
 static inline void __meminit print_mapping(unsigned long start,
@@ -243,11 +264,34 @@ static void __init radix_init_pgtable(void)
 	for_each_memblock(memory, reg)
 		WARN_ON(create_physical_mapping(reg->base,
 						reg->base + reg->size));
+
+	/* Find out how many PID bits are supported */
+	if (cpu_has_feature(CPU_FTR_HVMODE)) {
+		if (!mmu_pid_bits)
+			mmu_pid_bits = 20;
+#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
+		/*
+		 * When KVM is possible, we only use the top half of the
+		 * PID space to avoid collisions between host and guest PIDs
+		 * which can cause problems due to prefetch when exiting the
+		 * guest with AIL=3
+		 */
+		mmu_base_pid = 1 << (mmu_pid_bits - 1);
+#else
+		mmu_base_pid = 1;
+#endif
+	} else {
+		/* The guest uses the bottom half of the PID space */
+		if (!mmu_pid_bits)
+			mmu_pid_bits = 19;
+		mmu_base_pid = 1;
+	}
+
 	/*
 	 * Allocate Partition table and process table for the
 	 * host.
 	 */
-	BUILD_BUG_ON_MSG((PRTB_SIZE_SHIFT > 36), "Process table size too large.");
+	BUG_ON(PRTB_SIZE_SHIFT > 36);
 	process_tb = early_alloc_pgtable(1UL << PRTB_SIZE_SHIFT);
 	/*
 	 * Fill in the process table.
@@ -321,6 +365,12 @@ static int __init radix_dt_scan_page_sizes(unsigned long node,
 	if (type == NULL || strcmp(type, "cpu") != 0)
 		return 0;
 
+	/* Find MMU PID size */
+	prop = of_get_flat_dt_prop(node, "ibm,mmu-pid-bits", &size);
+	if (prop && size == 4)
+		mmu_pid_bits = be32_to_cpup(prop);
+
+	/* Grab page size encodings */
 	prop = of_get_flat_dt_prop(node, "ibm,processor-radix-AP-encodings", &size);
 	if (!prop)
 		return 0;