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Date: Thu, 25 May 2017 23:33:30 +0300
From: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To: Linus Torvalds <torvalds@...ux-foundation.org>,
Andrew Morton <akpm@...ux-foundation.org>, x86@...nel.org,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>
Cc: Andi Kleen <ak@...ux.intel.com>,
Dave Hansen <dave.hansen@...el.com>,
Andy Lutomirski <luto@...capital.net>,
linux-arch@...r.kernel.org, linux-mm@...ck.org,
linux-kernel@...r.kernel.org,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: [PATCHv1, RFC 4/8] x86/mm: Handle boot-time paging mode switching at early boot
This patch adds detection of 5-level paging at boot-time and adjusts
virtual memory layout and folds p4d page table layer if needed.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
---
arch/x86/include/asm/page_64_types.h | 13 +++----
arch/x86/include/asm/pgtable_64_types.h | 37 +++++++++++++-------
arch/x86/include/asm/processor.h | 2 +-
arch/x86/kernel/head64.c | 62 +++++++++++++++++++++++++--------
arch/x86/kernel/head_64.S | 16 +++++----
arch/x86/mm/kaslr.c | 2 +-
6 files changed, 90 insertions(+), 42 deletions(-)
diff --git a/arch/x86/include/asm/page_64_types.h b/arch/x86/include/asm/page_64_types.h
index 0126d6bc2eb1..26056ef366b8 100644
--- a/arch/x86/include/asm/page_64_types.h
+++ b/arch/x86/include/asm/page_64_types.h
@@ -36,24 +36,21 @@
* hypervisor to fit. Choosing 16 slots here is arbitrary, but it's
* what Xen requires.
*/
-#ifdef CONFIG_X86_5LEVEL
-#define __PAGE_OFFSET_BASE _AC(0xff10000000000000, UL)
-#else
-#define __PAGE_OFFSET_BASE _AC(0xffff880000000000, UL)
-#endif
+#define __PAGE_OFFSET_BASE57 _AC(0xff10000000000000, UL)
+#define __PAGE_OFFSET_BASE48 _AC(0xffff880000000000, UL)
#if defined(CONFIG_RANDOMIZE_MEMORY) || defined(CONFIG_X86_5LEVEL)
#define __PAGE_OFFSET page_offset_base
#else
-#define __PAGE_OFFSET __PAGE_OFFSET_BASE
+#define __PAGE_OFFSET __PAGE_OFFSET_BASE48
#endif /* CONFIG_RANDOMIZE_MEMORY */
#define __START_KERNEL_map _AC(0xffffffff80000000, UL)
/* See Documentation/x86/x86_64/mm.txt for a description of the memory map. */
#ifdef CONFIG_X86_5LEVEL
-#define __PHYSICAL_MASK_SHIFT 52
-#define __VIRTUAL_MASK_SHIFT 56
+#define __PHYSICAL_MASK_SHIFT (p4d_folded ? 52 : 46)
+#define __VIRTUAL_MASK_SHIFT (p4d_folded ? 47 : 56)
#else
#define __PHYSICAL_MASK_SHIFT 46
#define __VIRTUAL_MASK_SHIFT 47
diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
index a09f2fa91e09..46f52da75e16 100644
--- a/arch/x86/include/asm/pgtable_64_types.h
+++ b/arch/x86/include/asm/pgtable_64_types.h
@@ -19,6 +19,12 @@ typedef unsigned long pgprotval_t;
typedef struct { pteval_t pte; } pte_t;
+#ifdef CONFIG_X86_5LEVEL
+extern unsigned int p4d_folded;
+#else
+#define p4d_folded 1
+#endif
+
extern unsigned int pgdir_shift;
extern unsigned int ptrs_per_p4d;
@@ -79,23 +85,30 @@ extern unsigned int ptrs_per_p4d;
/* See Documentation/x86/x86_64/mm.txt for a description of the memory map. */
#define MAXMEM _AC(__AC(1, UL) << MAX_PHYSMEM_BITS, UL)
-#ifdef CONFIG_X86_5LEVEL
-#define VMALLOC_SIZE_TB _AC(16384, UL)
-#define __VMALLOC_BASE _AC(0xff92000000000000, UL)
-#define __VMEMMAP_BASE _AC(0xffd4000000000000, UL)
-#else
-#define VMALLOC_SIZE_TB _AC(32, UL)
-#define __VMALLOC_BASE _AC(0xffffc90000000000, UL)
-#define __VMEMMAP_BASE _AC(0xffffea0000000000, UL)
-#endif
+
+#ifndef __ASSEMBLY__
+#define __VMALLOC_BASE48 0xffffc90000000000
+#define __VMALLOC_BASE57 0xff92000000000000
+
+#define VMALLOC_SIZE_TB48 32UL
+#define VMALLOC_SIZE_TB57 16384UL
+
+#define __VMEMMAP_BASE48 0xffffea0000000000
+#define __VMEMMAP_BASE57 0xffd4000000000000
+
#if defined(CONFIG_RANDOMIZE_MEMORY) || defined(CONFIG_X86_5LEVEL)
#define VMALLOC_START vmalloc_base
+#define VMALLOC_SIZE_TB (!p4d_folded ? VMALLOC_SIZE_TB57 : VMALLOC_SIZE_TB48)
#define VMEMMAP_START vmemmap_base
#else
-#define VMALLOC_START __VMALLOC_BASE
-#define VMEMMAP_START __VMEMMAP_BASE
+#define VMALLOC_START __VMALLOC_BASE48
+#define VMALLOC_SIZE_TB VMALLOC_SIZE_TB48
+#define VMEMMAP_START __VMEMMAP_BASE48
#endif /* CONFIG_RANDOMIZE_MEMORY */
-#define VMALLOC_END (VMALLOC_START + _AC((VMALLOC_SIZE_TB << 40) - 1, UL))
+
+#define VMALLOC_END (VMALLOC_START + (VMALLOC_SIZE_TB << 40) - 1)
+#endif
+
#define MODULES_VADDR (__START_KERNEL_map + KERNEL_IMAGE_SIZE)
/* The module sections ends with the start of the fixmap */
#define MODULES_END __fix_to_virt(__end_of_fixed_addresses + 1)
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 65663de9287b..92c3f33f7682 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -854,7 +854,7 @@ static inline void spin_lock_prefetch(const void *x)
IA32_PAGE_OFFSET : TASK_SIZE_MAX)
#define STACK_TOP TASK_SIZE_LOW
-#define STACK_TOP_MAX TASK_SIZE_MAX
+#define STACK_TOP_MAX (!p4d_folded ? TASK_SIZE_MAX : DEFAULT_MAP_WINDOW)
#define INIT_THREAD { \
.sp0 = TOP_OF_INIT_STACK, \
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index d4e8d4beeb62..47629f3e32aa 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -39,26 +39,54 @@ static unsigned int __initdata next_early_pgt;
pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX);
#ifdef CONFIG_X86_5LEVEL
-unsigned int pgdir_shift = 48;
+unsigned int pgdir_shift = 39;
EXPORT_SYMBOL(pgdir_shift);
-unsigned int ptrs_per_p4d = 512;
+unsigned int ptrs_per_p4d = 1;
EXPORT_SYMBOL(ptrs_per_p4d);
#endif
-#if defined(CONFIG_RANDOMIZE_MEMORY) || defined(CONFIG_X86_5LEVEL)
-unsigned long page_offset_base = __PAGE_OFFSET_BASE;
+unsigned long page_offset_base = __PAGE_OFFSET_BASE48;
EXPORT_SYMBOL(page_offset_base);
-unsigned long vmalloc_base = __VMALLOC_BASE;
+unsigned long vmalloc_base = __VMALLOC_BASE48;
EXPORT_SYMBOL(vmalloc_base);
-unsigned long vmemmap_base = __VMEMMAP_BASE;
+unsigned long vmemmap_base = __VMEMMAP_BASE48;
EXPORT_SYMBOL(vmemmap_base);
-#endif
static void __init *fixup_pointer(void *ptr, unsigned long physaddr)
{
return ptr - (void *)_text + (void *)physaddr;
}
+static unsigned long __init *fixup_long(void *ptr, unsigned long physaddr)
+{
+ return fixup_pointer(ptr, physaddr);
+}
+
+#ifdef CONFIG_X86_5LEVEL
+static unsigned int __init *fixup_int(void *ptr, unsigned long physaddr)
+{
+ return fixup_pointer(ptr, physaddr);
+}
+
+static void __init check_la57_support(unsigned long physaddr)
+{
+ if (native_cpuid_eax(0) < 7)
+ return;
+
+ if (!(native_cpuid_ecx(7) & (1 << (X86_FEATURE_LA57 & 31))))
+ return;
+
+ *fixup_int(&p4d_folded, physaddr) = 0;
+ *fixup_int(&pgdir_shift, physaddr) = 48;
+ *fixup_int(&ptrs_per_p4d, physaddr) = 512;
+ *fixup_long(&page_offset_base, physaddr) = __PAGE_OFFSET_BASE57;
+ *fixup_long(&vmalloc_base, physaddr) = __VMALLOC_BASE57;
+ *fixup_long(&vmemmap_base, physaddr) = __VMEMMAP_BASE57;
+}
+#else
+static void __init check_la57_support(unsigned long physaddr) {}
+#endif
+
void __init __startup_64(unsigned long physaddr)
{
unsigned long load_delta, *p;
@@ -68,6 +96,8 @@ void __init __startup_64(unsigned long physaddr)
pmdval_t *pmd, pmd_entry;
int i;
+ check_la57_support(physaddr);
+
/* Is the address too large? */
if (physaddr >> MAX_PHYSMEM_BITS)
for (;;);
@@ -85,9 +115,14 @@ void __init __startup_64(unsigned long physaddr)
/* Fixup the physical addresses in the page table */
pgd = fixup_pointer(&early_top_pgt, physaddr);
- pgd[pgd_index(__START_KERNEL_map)] += load_delta;
-
- if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
+ p = pgd + pgd_index(__START_KERNEL_map);
+ if (p4d_folded)
+ *p = (unsigned long)level3_kernel_pgt;
+ else
+ *p = (unsigned long)level4_kernel_pgt;
+ *p += _PAGE_TABLE - __START_KERNEL_map + load_delta;
+
+ if (!p4d_folded) {
p4d = fixup_pointer(&level4_kernel_pgt, physaddr);
p4d[511] += load_delta;
}
@@ -109,7 +144,7 @@ void __init __startup_64(unsigned long physaddr)
pud = fixup_pointer(early_dynamic_pgts[next_early_pgt++], physaddr);
pmd = fixup_pointer(early_dynamic_pgts[next_early_pgt++], physaddr);
- if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
+ if (!p4d_folded) {
p4d = fixup_pointer(early_dynamic_pgts[next_early_pgt++], physaddr);
i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
@@ -151,8 +186,7 @@ void __init __startup_64(unsigned long physaddr)
}
/* Fixup phys_base */
- p = fixup_pointer(&phys_base, physaddr);
- *p += load_delta;
+ *fixup_long(&phys_base, physaddr) += load_delta;
}
/* Wipe all early page tables except for the kernel symbol map */
@@ -185,7 +219,7 @@ int __init early_make_pgtable(unsigned long address)
* critical -- __PAGE_OFFSET would point us back into the dynamic
* range and we might end up looping forever...
*/
- if (!IS_ENABLED(CONFIG_X86_5LEVEL))
+ if (p4d_folded)
p4d_p = pgd_p;
else if (pgd)
p4d_p = (p4dval_t *)((pgd & PTE_PFN_MASK) + __START_KERNEL_map - phys_base);
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 6225550883df..2009d9849e98 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -104,7 +104,10 @@ ENTRY(secondary_startup_64)
/* Enable PAE mode, PGE and LA57 */
movl $(X86_CR4_PAE | X86_CR4_PGE), %ecx
#ifdef CONFIG_X86_5LEVEL
+ testl $1, p4d_folded(%rip)
+ jnz 1f
orl $X86_CR4_LA57, %ecx
+1:
#endif
movq %rcx, %cr4
@@ -333,12 +336,7 @@ GLOBAL(name)
__INITDATA
NEXT_PAGE(early_top_pgt)
- .fill 511,8,0
-#ifdef CONFIG_X86_5LEVEL
- .quad level4_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE
-#else
- .quad level3_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE
-#endif
+ .fill 512,8,0
NEXT_PAGE(early_dynamic_pgts)
.fill 512*EARLY_DYNAMIC_PAGE_TABLES,8,0
@@ -417,6 +415,12 @@ ENTRY(phys_base)
.quad 0x0000000000000000
EXPORT_SYMBOL(phys_base)
+#ifdef CONFIG_X86_5LEVEL
+ENTRY(p4d_folded)
+ .word 1
+EXPORT_SYMBOL(p4d_folded)
+#endif
+
#include "../../x86/xen/xen-head.S"
__PAGE_ALIGNED_BSS
diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
index e6420b18f6e0..55433f2d1957 100644
--- a/arch/x86/mm/kaslr.c
+++ b/arch/x86/mm/kaslr.c
@@ -43,7 +43,7 @@
* before. You also need to add a BUILD_BUG_ON() in kernel_randomize_memory() to
* ensure that this order is correct and won't be changed.
*/
-static const unsigned long vaddr_start = __PAGE_OFFSET_BASE;
+static const unsigned long vaddr_start = __PAGE_OFFSET_BASE48;
#if defined(CONFIG_X86_ESPFIX64)
static const unsigned long vaddr_end = ESPFIX_BASE_ADDR;
--
2.11.0
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