arm64/mmu: replace 'page_mappings_only' parameter with flags argument

In preparation of extending the policy for manipulating kernel mappings
with whether or not contiguous hints may be used in the page tables,
replace the bool 'page_mappings_only' with a flags field and a flag
NO_BLOCK_MAPPINGS.
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/mm/mmu.c

@@ -43,6 +43,8 @@
 #include <asm/mmu_context.h>
 #include <asm/ptdump.h>
 
+#define NO_BLOCK_MAPPINGS	BIT(0)
+
 u64 idmap_t0sz = TCR_T0SZ(VA_BITS);
 
 u64 kimage_voffset __ro_after_init;
@@ -153,7 +155,7 @@ static void alloc_init_pte(pmd_t *pmd, unsigned long addr,
 static void alloc_init_pmd(pud_t *pud, unsigned long addr, unsigned long end,
 				  phys_addr_t phys, pgprot_t prot,
 				  phys_addr_t (*pgtable_alloc)(void),
-				  bool page_mappings_only)
+				  int flags)
 {
 	pmd_t *pmd;
 	unsigned long next;
@@ -180,7 +182,7 @@ static void alloc_init_pmd(pud_t *pud, unsigned long addr, unsigned long end,
 
 		/* try section mapping first */
 		if (((addr | next | phys) & ~SECTION_MASK) == 0 &&
-		      !page_mappings_only) {
+		    (flags & NO_BLOCK_MAPPINGS) == 0) {
 			pmd_set_huge(pmd, phys, prot);
 
 			/*
@@ -217,7 +219,7 @@ static inline bool use_1G_block(unsigned long addr, unsigned long next,
 static void alloc_init_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
 				  phys_addr_t phys, pgprot_t prot,
 				  phys_addr_t (*pgtable_alloc)(void),
-				  bool page_mappings_only)
+				  int flags)
 {
 	pud_t *pud;
 	unsigned long next;
@@ -239,7 +241,8 @@ static void alloc_init_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
 		/*
 		 * For 4K granule only, attempt to put down a 1GB block
 		 */
-		if (use_1G_block(addr, next, phys) && !page_mappings_only) {
+		if (use_1G_block(addr, next, phys) &&
+		    (flags & NO_BLOCK_MAPPINGS) == 0) {
 			pud_set_huge(pud, phys, prot);
 
 			/*
@@ -250,7 +253,7 @@ static void alloc_init_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
 						      pud_val(*pud)));
 		} else {
 			alloc_init_pmd(pud, addr, next, phys, prot,
-				       pgtable_alloc, page_mappings_only);
+				       pgtable_alloc, flags);
 
 			BUG_ON(pud_val(old_pud) != 0 &&
 			       pud_val(old_pud) != pud_val(*pud));
@@ -265,7 +268,7 @@ static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
 				 unsigned long virt, phys_addr_t size,
 				 pgprot_t prot,
 				 phys_addr_t (*pgtable_alloc)(void),
-				 bool page_mappings_only)
+				 int flags)
 {
 	unsigned long addr, length, end, next;
 	pgd_t *pgd = pgd_offset_raw(pgdir, virt);
@@ -285,7 +288,7 @@ static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
 	do {
 		next = pgd_addr_end(addr, end);
 		alloc_init_pud(pgd, addr, next, phys, prot, pgtable_alloc,
-			       page_mappings_only);
+			       flags);
 		phys += next - addr;
 	} while (pgd++, addr = next, addr != end);
 }
@@ -314,17 +317,22 @@ static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt,
 			&phys, virt);
 		return;
 	}
-	__create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, false);
+	__create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, 0);
 }
 
 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
 			       unsigned long virt, phys_addr_t size,
 			       pgprot_t prot, bool page_mappings_only)
 {
+	int flags = 0;
+
 	BUG_ON(mm == &init_mm);
 
+	if (page_mappings_only)
+		flags = NO_BLOCK_MAPPINGS;
+
 	__create_pgd_mapping(mm->pgd, phys, virt, size, prot,
-			     pgd_pgtable_alloc, page_mappings_only);
+			     pgd_pgtable_alloc, flags);
 }
 
 static void update_mapping_prot(phys_addr_t phys, unsigned long virt,
@@ -336,7 +344,7 @@ static void update_mapping_prot(phys_addr_t phys, unsigned long virt,
 		return;
 	}
 
-	__create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, false);
+	__create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, 0);
 
 	/* flush the TLBs after updating live kernel mappings */
 	flush_tlb_kernel_range(virt, virt + size);
@@ -346,6 +354,10 @@ static void __init __map_memblock(pgd_t *pgd, phys_addr_t start, phys_addr_t end
 {
 	phys_addr_t kernel_start = __pa_symbol(_text);
 	phys_addr_t kernel_end = __pa_symbol(__init_begin);
+	int flags = 0;
+
+	if (debug_pagealloc_enabled())
+		flags = NO_BLOCK_MAPPINGS;
 
 	/*
 	 * Take care not to create a writable alias for the
@@ -356,8 +368,7 @@ static void __init __map_memblock(pgd_t *pgd, phys_addr_t start, phys_addr_t end
 	if (end < kernel_start || start >= kernel_end) {
 		__create_pgd_mapping(pgd, start, __phys_to_virt(start),
 				     end - start, PAGE_KERNEL,
-				     early_pgtable_alloc,
-				     debug_pagealloc_enabled());
+				     early_pgtable_alloc, flags);
 		return;
 	}
 
@@ -369,14 +380,12 @@ static void __init __map_memblock(pgd_t *pgd, phys_addr_t start, phys_addr_t end
 		__create_pgd_mapping(pgd, start,
 				     __phys_to_virt(start),
 				     kernel_start - start, PAGE_KERNEL,
-				     early_pgtable_alloc,
-				     debug_pagealloc_enabled());
+				     early_pgtable_alloc, flags);
 	if (kernel_end < end)
 		__create_pgd_mapping(pgd, kernel_end,
 				     __phys_to_virt(kernel_end),
 				     end - kernel_end, PAGE_KERNEL,
-				     early_pgtable_alloc,
-				     debug_pagealloc_enabled());
+				     early_pgtable_alloc, flags);
 
 	/*
 	 * Map the linear alias of the [_text, __init_begin) interval
@@ -388,7 +397,7 @@ static void __init __map_memblock(pgd_t *pgd, phys_addr_t start, phys_addr_t end
 	 */
 	__create_pgd_mapping(pgd, kernel_start, __phys_to_virt(kernel_start),
 			     kernel_end - kernel_start, PAGE_KERNEL,
-			     early_pgtable_alloc, false);
+			     early_pgtable_alloc, 0);
 }
 
 void __init mark_linear_text_alias_ro(void)
@@ -444,7 +453,7 @@ static void __init map_kernel_segment(pgd_t *pgd, void *va_start, void *va_end,
 	BUG_ON(!PAGE_ALIGNED(size));
 
 	__create_pgd_mapping(pgd, pa_start, (unsigned long)va_start, size, prot,
-			     early_pgtable_alloc, false);
+			     early_pgtable_alloc, 0);
 
 	vma->addr	= va_start;
 	vma->phys_addr	= pa_start;