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Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux…
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…/kernel/git/tip/tip

Pull x86 mm updates from Ingo Molnar:
 "Lots of changes in this cycle:

   - Lots of CPA (change page attribute) optimizations and related
     cleanups (Thomas Gleixner, Peter Zijstra)

   - Make lazy TLB mode even lazier (Rik van Riel)

   - Fault handler cleanups and improvements (Dave Hansen)

   - kdump, vmcore: Enable kdumping encrypted memory with AMD SME
     enabled (Lianbo Jiang)

   - Clean up VM layout documentation (Baoquan He, Ingo Molnar)

   - ... plus misc other fixes and enhancements"

* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (51 commits)
  x86/stackprotector: Remove the call to boot_init_stack_canary() from cpu_startup_entry()
  x86/mm: Kill stray kernel fault handling comment
  x86/mm: Do not warn about PCI BIOS W+X mappings
  resource: Clean it up a bit
  resource: Fix find_next_iomem_res() iteration issue
  resource: Include resource end in walk_*() interfaces
  x86/kexec: Correct KEXEC_BACKUP_SRC_END off-by-one error
  x86/mm: Remove spurious fault pkey check
  x86/mm/vsyscall: Consider vsyscall page part of user address space
  x86/mm: Add vsyscall address helper
  x86/mm: Fix exception table comments
  x86/mm: Add clarifying comments for user addr space
  x86/mm: Break out user address space handling
  x86/mm: Break out kernel address space handling
  x86/mm: Clarify hardware vs. software "error_code"
  x86/mm/tlb: Make lazy TLB mode lazier
  x86/mm/tlb: Add freed_tables element to flush_tlb_info
  x86/mm/tlb: Add freed_tables argument to flush_tlb_mm_range
  smp,cpumask: introduce on_each_cpu_cond_mask
  smp: use __cpumask_set_cpu in on_each_cpu_cond
  ...
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@torvalds
torvalds committed Oct 23, 2018
2 parents 382d72a + 977e4be commit 99792e0
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171 changes: 120 additions & 51 deletions Documentation/x86/x86_64/mm.txt
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Original file line number Diff line number Diff line change
@@ -1,55 +1,124 @@
====================================================
Complete virtual memory map with 4-level page tables
====================================================

Virtual memory map with 4 level page tables:

0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm
hole caused by [47:63] sign extension
ffff800000000000 - ffff87ffffffffff (=43 bits) guard hole, reserved for hypervisor
ffff880000000000 - ffffc7ffffffffff (=64 TB) direct mapping of all phys. memory
ffffc80000000000 - ffffc8ffffffffff (=40 bits) hole
ffffc90000000000 - ffffe8ffffffffff (=45 bits) vmalloc/ioremap space
ffffe90000000000 - ffffe9ffffffffff (=40 bits) hole
ffffea0000000000 - ffffeaffffffffff (=40 bits) virtual memory map (1TB)
... unused hole ...
ffffec0000000000 - fffffbffffffffff (=44 bits) kasan shadow memory (16TB)
... unused hole ...
vaddr_end for KASLR
fffffe0000000000 - fffffe7fffffffff (=39 bits) cpu_entry_area mapping
fffffe8000000000 - fffffeffffffffff (=39 bits) LDT remap for PTI
ffffff0000000000 - ffffff7fffffffff (=39 bits) %esp fixup stacks
... unused hole ...
ffffffef00000000 - fffffffeffffffff (=64 GB) EFI region mapping space
... unused hole ...
ffffffff80000000 - ffffffff9fffffff (=512 MB) kernel text mapping, from phys 0
ffffffffa0000000 - fffffffffeffffff (1520 MB) module mapping space
[fixmap start] - ffffffffff5fffff kernel-internal fixmap range
ffffffffff600000 - ffffffffff600fff (=4 kB) legacy vsyscall ABI
ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole

Virtual memory map with 5 level page tables:

0000000000000000 - 00ffffffffffffff (=56 bits) user space, different per mm
hole caused by [56:63] sign extension
ff00000000000000 - ff0fffffffffffff (=52 bits) guard hole, reserved for hypervisor
ff10000000000000 - ff8fffffffffffff (=55 bits) direct mapping of all phys. memory
ff90000000000000 - ff9fffffffffffff (=52 bits) LDT remap for PTI
ffa0000000000000 - ffd1ffffffffffff (=54 bits) vmalloc/ioremap space (12800 TB)
ffd2000000000000 - ffd3ffffffffffff (=49 bits) hole
ffd4000000000000 - ffd5ffffffffffff (=49 bits) virtual memory map (512TB)
... unused hole ...
ffdf000000000000 - fffffc0000000000 (=53 bits) kasan shadow memory (8PB)
... unused hole ...
vaddr_end for KASLR
fffffe0000000000 - fffffe7fffffffff (=39 bits) cpu_entry_area mapping
... unused hole ...
ffffff0000000000 - ffffff7fffffffff (=39 bits) %esp fixup stacks
... unused hole ...
ffffffef00000000 - fffffffeffffffff (=64 GB) EFI region mapping space
... unused hole ...
ffffffff80000000 - ffffffff9fffffff (=512 MB) kernel text mapping, from phys 0
ffffffffa0000000 - fffffffffeffffff (1520 MB) module mapping space
[fixmap start] - ffffffffff5fffff kernel-internal fixmap range
ffffffffff600000 - ffffffffff600fff (=4 kB) legacy vsyscall ABI
ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole
Notes:

- Negative addresses such as "-23 TB" are absolute addresses in bytes, counted down
from the top of the 64-bit address space. It's easier to understand the layout
when seen both in absolute addresses and in distance-from-top notation.

For example 0xffffe90000000000 == -23 TB, it's 23 TB lower than the top of the
64-bit address space (ffffffffffffffff).

Note that as we get closer to the top of the address space, the notation changes
from TB to GB and then MB/KB.

- "16M TB" might look weird at first sight, but it's an easier to visualize size
notation than "16 EB", which few will recognize at first sight as 16 exabytes.
It also shows it nicely how incredibly large 64-bit address space is.

========================================================================================================================
Start addr | Offset | End addr | Size | VM area description
========================================================================================================================
| | | |
0000000000000000 | 0 | 00007fffffffffff | 128 TB | user-space virtual memory, different per mm
__________________|____________|__________________|_________|___________________________________________________________
| | | |
0000800000000000 | +128 TB | ffff7fffffffffff | ~16M TB | ... huge, almost 64 bits wide hole of non-canonical
| | | | virtual memory addresses up to the -128 TB
| | | | starting offset of kernel mappings.
__________________|____________|__________________|_________|___________________________________________________________
|
| Kernel-space virtual memory, shared between all processes:
____________________________________________________________|___________________________________________________________
| | | |
ffff800000000000 | -128 TB | ffff87ffffffffff | 8 TB | ... guard hole, also reserved for hypervisor
ffff880000000000 | -120 TB | ffffc7ffffffffff | 64 TB | direct mapping of all physical memory (page_offset_base)
ffffc80000000000 | -56 TB | ffffc8ffffffffff | 1 TB | ... unused hole
ffffc90000000000 | -55 TB | ffffe8ffffffffff | 32 TB | vmalloc/ioremap space (vmalloc_base)
ffffe90000000000 | -23 TB | ffffe9ffffffffff | 1 TB | ... unused hole
ffffea0000000000 | -22 TB | ffffeaffffffffff | 1 TB | virtual memory map (vmemmap_base)
ffffeb0000000000 | -21 TB | ffffebffffffffff | 1 TB | ... unused hole
ffffec0000000000 | -20 TB | fffffbffffffffff | 16 TB | KASAN shadow memory
fffffc0000000000 | -4 TB | fffffdffffffffff | 2 TB | ... unused hole
| | | | vaddr_end for KASLR
fffffe0000000000 | -2 TB | fffffe7fffffffff | 0.5 TB | cpu_entry_area mapping
fffffe8000000000 | -1.5 TB | fffffeffffffffff | 0.5 TB | LDT remap for PTI
ffffff0000000000 | -1 TB | ffffff7fffffffff | 0.5 TB | %esp fixup stacks
__________________|____________|__________________|_________|____________________________________________________________
|
| Identical layout to the 47-bit one from here on:
____________________________________________________________|____________________________________________________________
| | | |
ffffff8000000000 | -512 GB | ffffffeeffffffff | 444 GB | ... unused hole
ffffffef00000000 | -68 GB | fffffffeffffffff | 64 GB | EFI region mapping space
ffffffff00000000 | -4 GB | ffffffff7fffffff | 2 GB | ... unused hole
ffffffff80000000 | -2 GB | ffffffff9fffffff | 512 MB | kernel text mapping, mapped to physical address 0
ffffffff80000000 |-2048 MB | | |
ffffffffa0000000 |-1536 MB | fffffffffeffffff | 1520 MB | module mapping space
ffffffffff000000 | -16 MB | | |
FIXADDR_START | ~-11 MB | ffffffffff5fffff | ~0.5 MB | kernel-internal fixmap range, variable size and offset
ffffffffff600000 | -10 MB | ffffffffff600fff | 4 kB | legacy vsyscall ABI
ffffffffffe00000 | -2 MB | ffffffffffffffff | 2 MB | ... unused hole
__________________|____________|__________________|_________|___________________________________________________________


====================================================
Complete virtual memory map with 5-level page tables
====================================================

Notes:

- With 56-bit addresses, user-space memory gets expanded by a factor of 512x,
from 0.125 PB to 64 PB. All kernel mappings shift down to the -64 PT starting
offset and many of the regions expand to support the much larger physical
memory supported.

========================================================================================================================
Start addr | Offset | End addr | Size | VM area description
========================================================================================================================
| | | |
0000000000000000 | 0 | 00ffffffffffffff | 64 PB | user-space virtual memory, different per mm
__________________|____________|__________________|_________|___________________________________________________________
| | | |
0000800000000000 | +64 PB | ffff7fffffffffff | ~16K PB | ... huge, still almost 64 bits wide hole of non-canonical
| | | | virtual memory addresses up to the -128 TB
| | | | starting offset of kernel mappings.
__________________|____________|__________________|_________|___________________________________________________________
|
| Kernel-space virtual memory, shared between all processes:
____________________________________________________________|___________________________________________________________
| | | |
ff00000000000000 | -64 PB | ff0fffffffffffff | 4 PB | ... guard hole, also reserved for hypervisor
ff10000000000000 | -60 PB | ff8fffffffffffff | 32 PB | direct mapping of all physical memory (page_offset_base)
ff90000000000000 | -28 PB | ff9fffffffffffff | 4 PB | LDT remap for PTI
ffa0000000000000 | -24 PB | ffd1ffffffffffff | 12.5 PB | vmalloc/ioremap space (vmalloc_base)
ffd2000000000000 | -11.5 PB | ffd3ffffffffffff | 0.5 PB | ... unused hole
ffd4000000000000 | -11 PB | ffd5ffffffffffff | 0.5 PB | virtual memory map (vmemmap_base)
ffd6000000000000 | -10.5 PB | ffdeffffffffffff | 2.25 PB | ... unused hole
ffdf000000000000 | -8.25 PB | fffffdffffffffff | ~8 PB | KASAN shadow memory
fffffc0000000000 | -4 TB | fffffdffffffffff | 2 TB | ... unused hole
| | | | vaddr_end for KASLR
fffffe0000000000 | -2 TB | fffffe7fffffffff | 0.5 TB | cpu_entry_area mapping
fffffe8000000000 | -1.5 TB | fffffeffffffffff | 0.5 TB | ... unused hole
ffffff0000000000 | -1 TB | ffffff7fffffffff | 0.5 TB | %esp fixup stacks
__________________|____________|__________________|_________|____________________________________________________________
|
| Identical layout to the 47-bit one from here on:
____________________________________________________________|____________________________________________________________
| | | |
ffffff8000000000 | -512 GB | ffffffeeffffffff | 444 GB | ... unused hole
ffffffef00000000 | -68 GB | fffffffeffffffff | 64 GB | EFI region mapping space
ffffffff00000000 | -4 GB | ffffffff7fffffff | 2 GB | ... unused hole
ffffffff80000000 | -2 GB | ffffffff9fffffff | 512 MB | kernel text mapping, mapped to physical address 0
ffffffff80000000 |-2048 MB | | |
ffffffffa0000000 |-1536 MB | fffffffffeffffff | 1520 MB | module mapping space
ffffffffff000000 | -16 MB | | |
FIXADDR_START | ~-11 MB | ffffffffff5fffff | ~0.5 MB | kernel-internal fixmap range, variable size and offset
ffffffffff600000 | -10 MB | ffffffffff600fff | 4 kB | legacy vsyscall ABI
ffffffffffe00000 | -2 MB | ffffffffffffffff | 2 MB | ... unused hole
__________________|____________|__________________|_________|___________________________________________________________

Architecture defines a 64-bit virtual address. Implementations can support
less. Currently supported are 48- and 57-bit virtual addresses. Bits 63
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8 changes: 8 additions & 0 deletions arch/x86/Kconfig
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Expand Up @@ -1487,6 +1487,14 @@ config X86_DIRECT_GBPAGES
supports them), so don't confuse the user by printing
that we have them enabled.

config X86_CPA_STATISTICS
bool "Enable statistic for Change Page Attribute"
depends on DEBUG_FS
---help---
Expose statistics about the Change Page Attribute mechanims, which
helps to determine the effectivness of preserving large and huge
page mappings when mapping protections are changed.

config ARCH_HAS_MEM_ENCRYPT
def_bool y

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3 changes: 2 additions & 1 deletion arch/x86/include/asm/io.h
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Expand Up @@ -187,11 +187,12 @@ extern void __iomem *ioremap_nocache(resource_size_t offset, unsigned long size)
#define ioremap_nocache ioremap_nocache
extern void __iomem *ioremap_uc(resource_size_t offset, unsigned long size);
#define ioremap_uc ioremap_uc

extern void __iomem *ioremap_cache(resource_size_t offset, unsigned long size);
#define ioremap_cache ioremap_cache
extern void __iomem *ioremap_prot(resource_size_t offset, unsigned long size, unsigned long prot_val);
#define ioremap_prot ioremap_prot
extern void __iomem *ioremap_encrypted(resource_size_t phys_addr, unsigned long size);
#define ioremap_encrypted ioremap_encrypted

/**
* ioremap - map bus memory into CPU space
Expand Down
2 changes: 1 addition & 1 deletion arch/x86/include/asm/kexec.h
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Original file line number Diff line number Diff line change
Expand Up @@ -67,7 +67,7 @@ struct kimage;

/* Memory to backup during crash kdump */
#define KEXEC_BACKUP_SRC_START (0UL)
#define KEXEC_BACKUP_SRC_END (640 * 1024UL) /* 640K */
#define KEXEC_BACKUP_SRC_END (640 * 1024UL - 1) /* 640K */

/*
* CPU does not save ss and sp on stack if execution is already
Expand Down
15 changes: 9 additions & 6 deletions arch/x86/include/asm/page_64_types.h
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Original file line number Diff line number Diff line change
Expand Up @@ -59,13 +59,16 @@
#endif

/*
* Kernel image size is limited to 1GiB due to the fixmap living in the
* next 1GiB (see level2_kernel_pgt in arch/x86/kernel/head_64.S). Use
* 512MiB by default, leaving 1.5GiB for modules once the page tables
* are fully set up. If kernel ASLR is configured, it can extend the
* kernel page table mapping, reducing the size of the modules area.
* Maximum kernel image size is limited to 1 GiB, due to the fixmap living
* in the next 1 GiB (see level2_kernel_pgt in arch/x86/kernel/head_64.S).
*
* On KASLR use 1 GiB by default, leaving 1 GiB for modules once the
* page tables are fully set up.
*
* If KASLR is disabled we can shrink it to 0.5 GiB and increase the size
* of the modules area to 1.5 GiB.
*/
#if defined(CONFIG_RANDOMIZE_BASE)
#ifdef CONFIG_RANDOMIZE_BASE
#define KERNEL_IMAGE_SIZE (1024 * 1024 * 1024)
#else
#define KERNEL_IMAGE_SIZE (512 * 1024 * 1024)
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21 changes: 14 additions & 7 deletions arch/x86/include/asm/tlb.h
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Original file line number Diff line number Diff line change
Expand Up @@ -6,16 +6,23 @@
#define tlb_end_vma(tlb, vma) do { } while (0)
#define __tlb_remove_tlb_entry(tlb, ptep, address) do { } while (0)

#define tlb_flush(tlb) \
{ \
if (!tlb->fullmm && !tlb->need_flush_all) \
flush_tlb_mm_range(tlb->mm, tlb->start, tlb->end, 0UL); \
else \
flush_tlb_mm_range(tlb->mm, 0UL, TLB_FLUSH_ALL, 0UL); \
}
static inline void tlb_flush(struct mmu_gather *tlb);

#include <asm-generic/tlb.h>

static inline void tlb_flush(struct mmu_gather *tlb)
{
unsigned long start = 0UL, end = TLB_FLUSH_ALL;
unsigned int stride_shift = tlb_get_unmap_shift(tlb);

if (!tlb->fullmm && !tlb->need_flush_all) {
start = tlb->start;
end = tlb->end;
}

flush_tlb_mm_range(tlb->mm, start, end, stride_shift, tlb->freed_tables);
}

/*
* While x86 architecture in general requires an IPI to perform TLB
* shootdown, enablement code for several hypervisors overrides
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33 changes: 12 additions & 21 deletions arch/x86/include/asm/tlbflush.h
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Original file line number Diff line number Diff line change
Expand Up @@ -148,22 +148,6 @@ static inline unsigned long build_cr3_noflush(pgd_t *pgd, u16 asid)
#define __flush_tlb_one_user(addr) __native_flush_tlb_one_user(addr)
#endif

static inline bool tlb_defer_switch_to_init_mm(void)
{
/*
* If we have PCID, then switching to init_mm is reasonably
* fast. If we don't have PCID, then switching to init_mm is
* quite slow, so we try to defer it in the hopes that we can
* avoid it entirely. The latter approach runs the risk of
* receiving otherwise unnecessary IPIs.
*
* This choice is just a heuristic. The tlb code can handle this
* function returning true or false regardless of whether we have
* PCID.
*/
return !static_cpu_has(X86_FEATURE_PCID);
}

struct tlb_context {
u64 ctx_id;
u64 tlb_gen;
Expand Down Expand Up @@ -547,23 +531,30 @@ struct flush_tlb_info {
unsigned long start;
unsigned long end;
u64 new_tlb_gen;
unsigned int stride_shift;
bool freed_tables;
};

#define local_flush_tlb() __flush_tlb()

#define flush_tlb_mm(mm) flush_tlb_mm_range(mm, 0UL, TLB_FLUSH_ALL, 0UL)
#define flush_tlb_mm(mm) \
flush_tlb_mm_range(mm, 0UL, TLB_FLUSH_ALL, 0UL, true)

#define flush_tlb_range(vma, start, end) \
flush_tlb_mm_range(vma->vm_mm, start, end, vma->vm_flags)
#define flush_tlb_range(vma, start, end) \
flush_tlb_mm_range((vma)->vm_mm, start, end, \
((vma)->vm_flags & VM_HUGETLB) \
? huge_page_shift(hstate_vma(vma)) \
: PAGE_SHIFT, false)

extern void flush_tlb_all(void);
extern void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
unsigned long end, unsigned long vmflag);
unsigned long end, unsigned int stride_shift,
bool freed_tables);
extern void flush_tlb_kernel_range(unsigned long start, unsigned long end);

static inline void flush_tlb_page(struct vm_area_struct *vma, unsigned long a)
{
flush_tlb_mm_range(vma->vm_mm, a, a + PAGE_SIZE, VM_NONE);
flush_tlb_mm_range(vma->vm_mm, a, a + PAGE_SIZE, PAGE_SHIFT, false);
}

void native_flush_tlb_others(const struct cpumask *cpumask,
Expand Down
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