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From: Steve Capper <steve.capper@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: crecklin@redhat.com, ard.biesheuvel@linaro.org,
	marc.zyngier@arm.com, catalin.marinas@arm.com,
	bhsharma@redhat.com, will.deacon@arm.com
Subject: [PATCH v3 01/10] arm64: mm: Flip kernel VA space
Date: Wed, 12 Jun 2019 18:26:49 +0100	[thread overview]
Message-ID: <20190612172658.28522-2-steve.capper@arm.com> (raw)
In-Reply-To: <20190612172658.28522-1-steve.capper@arm.com>

Put the direct linear map in the lower addresses of the kernel VA range
and everything else in the higher ranges.

This allows us to make room for an inline KASAN shadow that operates
under both 48 and 52 bit kernel VA sizes. For example with a 52-bit VA,
if KASAN_SHADOW_END < 0xFFF8000000000000 (it is in the lower addresses
of the kernel VA range), this will be below the start of the minimum
48-bit kernel VA address of 0xFFFF000000000000.

We need to adjust:
 *) KASAN shadow region placement logic,
 *) KASAN_SHADOW_OFFSET computation logic,
 *) virt_to_phys, phys_to_virt checks,
 *) page table dumper.

These are all small changes, that need to take place atomically, so they
are bundled into this commit.

Signed-off-by: Steve Capper <steve.capper@arm.com>
---
 arch/arm64/Makefile              | 2 +-
 arch/arm64/include/asm/memory.h  | 8 ++++----
 arch/arm64/include/asm/pgtable.h | 2 +-
 arch/arm64/kernel/hibernate.c    | 2 +-
 arch/arm64/mm/dump.c             | 8 ++++----
 arch/arm64/mm/init.c             | 9 +--------
 arch/arm64/mm/kasan_init.c       | 6 +++---
 arch/arm64/mm/mmu.c              | 4 ++--
 8 files changed, 17 insertions(+), 24 deletions(-)

diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index b025304bde46..2dad2ae6b181 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -115,7 +115,7 @@ KBUILD_AFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)
 #				 - (1 << (64 - KASAN_SHADOW_SCALE_SHIFT))
 # in 32-bit arithmetic
 KASAN_SHADOW_OFFSET := $(shell printf "0x%08x00000000\n" $$(( \
-	(0xffffffff & (-1 << ($(CONFIG_ARM64_VA_BITS) - 32))) \
+	(0xffffffff & (-1 << ($(CONFIG_ARM64_VA_BITS) - 1 - 32))) \
 	+ (1 << ($(CONFIG_ARM64_VA_BITS) - 32 - $(KASAN_SHADOW_SCALE_SHIFT))) \
 	- (1 << (64 - 32 - $(KASAN_SHADOW_SCALE_SHIFT))) )) )
 
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 8ffcf5a512bb..5cd2eb8cb424 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -49,9 +49,9 @@
  */
 #define VA_BITS			(CONFIG_ARM64_VA_BITS)
 #define VA_START		(UL(0xffffffffffffffff) - \
-	(UL(1) << VA_BITS) + 1)
-#define PAGE_OFFSET		(UL(0xffffffffffffffff) - \
 	(UL(1) << (VA_BITS - 1)) + 1)
+#define PAGE_OFFSET		(UL(0xffffffffffffffff) - \
+	(UL(1) << VA_BITS) + 1)
 #define KIMAGE_VADDR		(MODULES_END)
 #define BPF_JIT_REGION_START	(VA_START + KASAN_SHADOW_SIZE)
 #define BPF_JIT_REGION_SIZE	(SZ_128M)
@@ -59,7 +59,7 @@
 #define MODULES_END		(MODULES_VADDR + MODULES_VSIZE)
 #define MODULES_VADDR		(BPF_JIT_REGION_END)
 #define MODULES_VSIZE		(SZ_128M)
-#define VMEMMAP_START		(PAGE_OFFSET - VMEMMAP_SIZE)
+#define VMEMMAP_START		(-VMEMMAP_SIZE)
 #define PCI_IO_END		(VMEMMAP_START - SZ_2M)
 #define PCI_IO_START		(PCI_IO_END - PCI_IO_SIZE)
 #define FIXADDR_TOP		(PCI_IO_START - SZ_2M)
@@ -238,7 +238,7 @@ extern u64			vabits_user;
  * space. Testing the top bit for the start of the region is a
  * sufficient check.
  */
-#define __is_lm_address(addr)	(!!((addr) & BIT(VA_BITS - 1)))
+#define __is_lm_address(addr)	(!((addr) & BIT(VA_BITS - 1)))
 
 #define __lm_to_phys(addr)	(((addr) & ~PAGE_OFFSET) + PHYS_OFFSET)
 #define __kimg_to_phys(addr)	((addr) - kimage_voffset)
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 2c41b04708fe..d0ab784304e9 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -32,7 +32,7 @@
  *	and fixed mappings
  */
 #define VMALLOC_START		(MODULES_END)
-#define VMALLOC_END		(PAGE_OFFSET - PUD_SIZE - VMEMMAP_SIZE - SZ_64K)
+#define VMALLOC_END		(- PUD_SIZE - VMEMMAP_SIZE - SZ_64K)
 
 #define vmemmap			((struct page *)VMEMMAP_START - (memstart_addr >> PAGE_SHIFT))
 
diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
index 9859e1178e6b..6ffcc32f35dd 100644
--- a/arch/arm64/kernel/hibernate.c
+++ b/arch/arm64/kernel/hibernate.c
@@ -497,7 +497,7 @@ int swsusp_arch_resume(void)
 		rc = -ENOMEM;
 		goto out;
 	}
-	rc = copy_page_tables(tmp_pg_dir, PAGE_OFFSET, 0);
+	rc = copy_page_tables(tmp_pg_dir, PAGE_OFFSET, VA_START);
 	if (rc)
 		goto out;
 
diff --git a/arch/arm64/mm/dump.c b/arch/arm64/mm/dump.c
index 14fe23cd5932..ee4e5bea8944 100644
--- a/arch/arm64/mm/dump.c
+++ b/arch/arm64/mm/dump.c
@@ -30,6 +30,8 @@
 #include <asm/ptdump.h>
 
 static const struct addr_marker address_markers[] = {
+	{ PAGE_OFFSET,			"Linear Mapping start" },
+	{ VA_START,			"Linear Mapping end" },
 #ifdef CONFIG_KASAN
 	{ KASAN_SHADOW_START,		"Kasan shadow start" },
 	{ KASAN_SHADOW_END,		"Kasan shadow end" },
@@ -43,10 +45,8 @@ static const struct addr_marker address_markers[] = {
 	{ PCI_IO_START,			"PCI I/O start" },
 	{ PCI_IO_END,			"PCI I/O end" },
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
-	{ VMEMMAP_START,		"vmemmap start" },
-	{ VMEMMAP_START + VMEMMAP_SIZE,	"vmemmap end" },
+	{ VMEMMAP_START,		"vmemmap" },
 #endif
-	{ PAGE_OFFSET,			"Linear mapping" },
 	{ -1,				NULL },
 };
 
@@ -380,7 +380,7 @@ static void ptdump_initialize(void)
 static struct ptdump_info kernel_ptdump_info = {
 	.mm		= &init_mm,
 	.markers	= address_markers,
-	.base_addr	= VA_START,
+	.base_addr	= PAGE_OFFSET,
 };
 
 void ptdump_check_wx(void)
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index d2adffb81b5d..574ed1d4be19 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -311,7 +311,7 @@ static void __init fdt_enforce_memory_region(void)
 
 void __init arm64_memblock_init(void)
 {
-	const s64 linear_region_size = -(s64)PAGE_OFFSET;
+	const s64 linear_region_size = BIT(VA_BITS - 1);
 
 	/* Handle linux,usable-memory-range property */
 	fdt_enforce_memory_region();
@@ -319,13 +319,6 @@ void __init arm64_memblock_init(void)
 	/* Remove memory above our supported physical address size */
 	memblock_remove(1ULL << PHYS_MASK_SHIFT, ULLONG_MAX);
 
-	/*
-	 * Ensure that the linear region takes up exactly half of the kernel
-	 * virtual address space. This way, we can distinguish a linear address
-	 * from a kernel/module/vmalloc address by testing a single bit.
-	 */
-	BUILD_BUG_ON(linear_region_size != BIT(VA_BITS - 1));
-
 	/*
 	 * Select a suitable value for the base of physical memory.
 	 */
diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
index 296de39ddee5..8066621052db 100644
--- a/arch/arm64/mm/kasan_init.c
+++ b/arch/arm64/mm/kasan_init.c
@@ -229,10 +229,10 @@ void __init kasan_init(void)
 	kasan_map_populate(kimg_shadow_start, kimg_shadow_end,
 			   early_pfn_to_nid(virt_to_pfn(lm_alias(_text))));
 
-	kasan_populate_early_shadow((void *)KASAN_SHADOW_START,
-				    (void *)mod_shadow_start);
+	kasan_populate_early_shadow(kasan_mem_to_shadow((void *) VA_START),
+				   (void *)mod_shadow_start);
 	kasan_populate_early_shadow((void *)kimg_shadow_end,
-				    kasan_mem_to_shadow((void *)PAGE_OFFSET));
+				   (void *)KASAN_SHADOW_END);
 
 	if (kimg_shadow_start > mod_shadow_end)
 		kasan_populate_early_shadow((void *)mod_shadow_end,
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index a1bfc4413982..16063ff10c6d 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -409,7 +409,7 @@ static phys_addr_t pgd_pgtable_alloc(int shift)
 static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt,
 				  phys_addr_t size, pgprot_t prot)
 {
-	if (virt < VMALLOC_START) {
+	if ((virt >= VA_START) && (virt < VMALLOC_START)) {
 		pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
 			&phys, virt);
 		return;
@@ -436,7 +436,7 @@ void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
 static void update_mapping_prot(phys_addr_t phys, unsigned long virt,
 				phys_addr_t size, pgprot_t prot)
 {
-	if (virt < VMALLOC_START) {
+	if ((virt >= VA_START) && (virt < VMALLOC_START)) {
 		pr_warn("BUG: not updating mapping for %pa at 0x%016lx - outside kernel range\n",
 			&phys, virt);
 		return;
-- 
2.20.1


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  reply	other threads:[~2019-06-12 17:27 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-12 17:26 [PATCH v3 00/10] 52-bit kernel + user VAs Steve Capper
2019-06-12 17:26 ` Steve Capper [this message]
2019-06-14 12:17   ` [PATCH v3 01/10] arm64: mm: Flip kernel VA space Anshuman Khandual
2019-06-17 16:09     ` Steve Capper
2019-06-26 10:56       ` Catalin Marinas
2019-06-14 13:00   ` Anshuman Khandual
2019-06-17 16:08     ` Steve Capper
2019-06-12 17:26 ` [PATCH v3 02/10] arm64: kasan: Switch to using KASAN_SHADOW_OFFSET Steve Capper
2019-06-12 17:26 ` [PATCH v3 03/10] arm64: dump: De-constify VA_START and KASAN_SHADOW_START Steve Capper
2019-06-12 17:26 ` [PATCH v3 04/10] arm64: mm: Introduce VA_BITS_MIN Steve Capper
2019-06-12 17:26 ` [PATCH v3 05/10] arm64: mm: Introduce VA_BITS_ACTUAL Steve Capper
2019-06-12 17:26 ` [PATCH v3 06/10] arm64: mm: Logic to make offset_ttbr1 conditional Steve Capper
2019-06-12 17:26 ` [PATCH v3 07/10] arm64: mm: Separate out vmemmap Steve Capper
2019-06-12 17:26 ` [PATCH v3 08/10] arm64: mm: Modify calculation of VMEMMAP_SIZE Steve Capper
2019-06-12 17:26 ` [PATCH v3 09/10] arm64: mm: Tweak PAGE_OFFSET logic Steve Capper
2019-06-12 17:26 ` [PATCH v3 10/10] arm64: mm: Introduce 52-bit Kernel VAs Steve Capper
2019-06-26 11:08 ` [PATCH v3 00/10] 52-bit kernel + user VAs Catalin Marinas

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