[RFC 5/8] arm64/mm: make trans_pgd_idmap_page() use create_idmap()

[Pingfan Liu]

At present, trans_pgd_idmap_page() has its own logic to set up idmap. To
make code simple, it can reuse create_idmap().

Signed-off-by: Pingfan Liu <kernelfans at gmail.com>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Will Deacon <will at kernel.org>
Cc: Marc Zyngier <maz at kernel.org>
Cc: Kristina Martsenko <kristina.martsenko at arm.com>
Cc: James Morse <james.morse at arm.com>
Cc: Steven Price <steven.price at arm.com>
Cc: Jonathan Cameron <Jonathan.Cameron at huawei.com>
Cc: Pavel Tatashin <pasha.tatashin at soleen.com>
Cc: Anshuman Khandual <anshuman.khandual at arm.com>
Cc: Atish Patra <atish.patra at wdc.com>
Cc: Mike Rapoport <rppt at kernel.org>
Cc: Logan Gunthorpe <logang at deltatee.com>
Cc: Mark Brown <broonie at kernel.org>
To: linux-arm-kernel at lists.infradead.org
---
 arch/arm64/include/asm/pgalloc.h |  9 +++++
 arch/arm64/mm/trans_pgd.c        | 59 +++++++++++++++-----------------
 2 files changed, 36 insertions(+), 32 deletions(-)

diff --git a/arch/arm64/include/asm/pgalloc.h b/arch/arm64/include/asm/pgalloc.h
index 6e9f1e218300..f848a0300228 100644
--- a/arch/arm64/include/asm/pgalloc.h
+++ b/arch/arm64/include/asm/pgalloc.h
@@ -93,6 +93,15 @@ extern void __create_pgd_mapping_extend(pgd_t *pgdir,
 		void *info,
 		int flags);
 
+extern int idmap_extend_pgtable;
+
+extern void create_idmap(pgd_t *pgdir, phys_addr_t phys,
+		phys_addr_t size,
+		pgprot_t prot,
+		pgtable_alloc allocator,
+		void *info,
+		int flags);
+
 #define NO_BLOCK_MAPPINGS	BIT(0)
 #define NO_CONT_MAPPINGS	BIT(1)
 #define NO_FIXMAP	BIT(2)
diff --git a/arch/arm64/mm/trans_pgd.c b/arch/arm64/mm/trans_pgd.c
index 527f0a39c3da..004ccbadd647 100644
--- a/arch/arm64/mm/trans_pgd.c
+++ b/arch/arm64/mm/trans_pgd.c
@@ -274,6 +274,14 @@ int trans_pgd_map_page(struct trans_pgd_info *info, pgd_t *trans_pgd,
 	return 0;
 }
 
+static unsigned long allocator_trans_alloc(unsigned long unused, void *info)
+{
+	unsigned long *p;
+
+	p = trans_alloc(info);
+	return (unsigned long)p;
+}
+
 /*
  * The page we want to idmap may be outside the range covered by VA_BITS that
  * can be built using the kernel's p?d_populate() helpers. As a one off, for a
@@ -287,38 +295,25 @@ int trans_pgd_map_page(struct trans_pgd_info *info, pgd_t *trans_pgd,
 int trans_pgd_idmap_page(struct trans_pgd_info *info, phys_addr_t *trans_ttbr0,
 			 unsigned long *t0sz, void *page)
 {
-	phys_addr_t dst_addr = virt_to_phys(page);
-	unsigned long pfn = __phys_to_pfn(dst_addr);
-	int max_msb = (dst_addr & GENMASK(52, 48)) ? 51 : 47;
-	int bits_mapped = PAGE_SHIFT - 4;
-	unsigned long level_mask, prev_level_entry, *levels[4];
-	int this_level, index, level_lsb, level_msb;
-
-	dst_addr &= PAGE_MASK;
-	prev_level_entry = pte_val(pfn_pte(pfn, PAGE_KERNEL_EXEC));
-
-	for (this_level = 3; this_level >= 0; this_level--) {
-		levels[this_level] = trans_alloc(info);
-		if (!levels[this_level])
-			return -ENOMEM;
-
-		level_lsb = ARM64_HW_PGTABLE_LEVEL_SHIFT(this_level);
-		level_msb = min(level_lsb + bits_mapped, max_msb);
-		level_mask = GENMASK_ULL(level_msb, level_lsb);
-
-		index = (dst_addr & level_mask) >> level_lsb;
-		*(levels[this_level] + index) = prev_level_entry;
-
-		pfn = virt_to_pfn(levels[this_level]);
-		prev_level_entry = pte_val(pfn_pte(pfn,
-						   __pgprot(PMD_TYPE_TABLE)));
-
-		if (level_msb == max_msb)
-			break;
-	}
-
-	*trans_ttbr0 = phys_to_ttbr(__pfn_to_phys(pfn));
-	*t0sz = TCR_T0SZ(max_msb + 1);
+	pgd_t * pgdir = trans_alloc(info);
+	int flags = NO_FIXMAP;
+	unsigned long base, step, level, va_bits;
+
+#ifdef CONFIG_ARM64_64K_PAGES
+	base = 16;
+	step = 13;
+#elif CONFIG_ARM64_4K_PAGES
+	base = 12;
+	step = 9;
+#endif
+	create_idmap(pgdir, virt_to_phys(page), PAGE_SIZE, PAGE_KERNEL_EXEC,
+			allocator_trans_alloc, info, flags);
+
+	*trans_ttbr0 = phys_to_ttbr(__virt_to_phys(pgdir));
+	level = CONFIG_PGTABLE_LEVELS + idmap_extend_pgtable ? 1 : 0;
+	va_bits = base + step * level;
+	va_bits = min(va_bits, vabits_actual);
+	*t0sz = 64 - va_bits;
 
 	return 0;
 }
-- 
2.29.2