diff options
Diffstat (limited to 'Documentation/x86/x86_64')
| -rw-r--r-- | Documentation/x86/x86_64/00-INDEX | 16 | ||||
| -rw-r--r-- | Documentation/x86/x86_64/boot-options.txt | 5 | ||||
| -rw-r--r-- | Documentation/x86/x86_64/mm.txt | 178 |
3 files changed, 126 insertions, 73 deletions
diff --git a/Documentation/x86/x86_64/00-INDEX b/Documentation/x86/x86_64/00-INDEX deleted file mode 100644 index 92fc20ab5f0e..000000000000 --- a/Documentation/x86/x86_64/00-INDEX +++ /dev/null @@ -1,16 +0,0 @@ -00-INDEX - - This file -boot-options.txt - - AMD64-specific boot options. -cpu-hotplug-spec - - Firmware support for CPU hotplug under Linux/x86-64 -fake-numa-for-cpusets - - Using numa=fake and CPUSets for Resource Management -kernel-stacks - - Context-specific per-processor interrupt stacks. -machinecheck - - Configurable sysfs parameters for the x86-64 machine check code. -mm.txt - - Memory layout of x86-64 (4 level page tables, 46 bits physical). -uefi.txt - - Booting Linux via Unified Extensible Firmware Interface. diff --git a/Documentation/x86/x86_64/boot-options.txt b/Documentation/x86/x86_64/boot-options.txt index ad6d2a80cf05..abc53886655e 100644 --- a/Documentation/x86/x86_64/boot-options.txt +++ b/Documentation/x86/x86_64/boot-options.txt @@ -209,7 +209,7 @@ IOMMU (input/output memory management unit) mapping with memory protection, etc. Kernel boot message: "PCI-DMA: Using Calgary IOMMU" - iommu=[<size>][,noagp][,off][,force][,noforce][,leak[=<nr_of_leak_pages>] + iommu=[<size>][,noagp][,off][,force][,noforce] [,memaper[=<order>]][,merge][,fullflush][,nomerge] [,noaperture][,calgary] @@ -228,9 +228,6 @@ IOMMU (input/output memory management unit) allowed Overwrite iommu off workarounds for specific chipsets. fullflush Flush IOMMU on each allocation (default). nofullflush Don't use IOMMU fullflush. - leak Turn on simple iommu leak tracing (only when - CONFIG_IOMMU_LEAK is on). Default number of leak pages - is 20. memaper[=<order>] Allocate an own aperture over RAM with size 32MB<<order. (default: order=1, i.e. 64MB) merge Do scatter-gather (SG) merging. Implies "force" diff --git a/Documentation/x86/x86_64/mm.txt b/Documentation/x86/x86_64/mm.txt index 05ef53d83a41..804f9426ed17 100644 --- a/Documentation/x86/x86_64/mm.txt +++ b/Documentation/x86/x86_64/mm.txt @@ -1,57 +1,126 @@ +==================================================== +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 - ffff887fffffffff (=39 bits) LDT remap for PTI -ffff888000000000 - ffffc87fffffffff (=64 TB) direct mapping of all phys. memory -ffffc88000000000 - ffffc8ffffffffff (=39 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 - ff10ffffffffffff (=48 bits) LDT remap for PTI -ff11000000000000 - ff90ffffffffffff (=55 bits) direct mapping of all phys. memory -ff91000000000000 - ff9fffffffffffff (=3840 TB) hole -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 | ffff887fffffffff | 0.5 TB | LDT remap for PTI + ffff888000000000 | -119.5 TB | ffffc87fffffffff | 64 TB | direct mapping of all physical memory (page_offset_base) + ffffc88000000000 | -55.5 TB | ffffc8ffffffffff | 0.5 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 +__________________|____________|__________________|_________|____________________________________________________________ + | + | Identical layout to the 56-bit one from here on: +____________________________________________________________|____________________________________________________________ + | | | | + 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 + 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 -64 PB + | | | | 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 | ff10ffffffffffff | 0.25 PB | LDT remap for PTI + ff11000000000000 | -59.75 PB | ff90ffffffffffff | 32 PB | direct mapping of all physical memory (page_offset_base) + ff91000000000000 | -27.75 PB | ff9fffffffffffff | 3.75 PB | ... unused hole + 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 +__________________|____________|__________________|_________|____________________________________________________________ + | + | Identical layout to the 47-bit one from here on: +____________________________________________________________|____________________________________________________________ + | | | | + 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 + 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 @@ -79,3 +148,6 @@ Their order is preserved but their base will be offset early at boot time. Be very careful vs. KASLR when changing anything here. The KASLR address range must not overlap with anything except the KASAN shadow area, which is correct as KASAN disables KASLR. + +For both 4- and 5-level layouts, the STACKLEAK_POISON value in the last 2MB +hole: ffffffffffff4111 |