Greg Kroah-Hartman
598cf27219
Link: https://lore.kernel.org/r/20260217200002.683975158@linuxfoundation.org Tested-by: Florian Fainelli <florian.fainelli@broadcom.com> Tested-by: Takeshi Ogasawara <takeshi.ogasawara@futuring-girl.com> Tested-by: Peter Schneider <pschneider1968@googlemail.com> Tested-by: Jon Hunter <jonathanh@nvidia.com> Tested-by: Salvatore Bonaccorso <carnil@debian.org> Tested-by: Brett A C Sheffield <bacs@librecast.net> Tested-by: Mark Brown <broonie@kernel.org> Tested-by: Luna Jernberg <droidbittin@gmail.com> Tested-by: Ronald Warsow <rwarsow@gmx.de> Tested-by: Justin M. Forbes <jforbes@fedoraproject.org> Tested-by: Ron Economos <re@w6rz.net> Tested-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
112 lines
3.2 KiB
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112 lines
3.2 KiB
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.. SPDX-License-Identifier: GPL-2.0
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=================
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Memory Management
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=================
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Virtual memory layout
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=====================
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.. note::
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- Some aspects of the virtual memory layout setup are not
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clarified (number of page levels, alignment, DMA memory).
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- Unused gaps in the virtual memory layout could be present
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or not - depending on how partucular system is configured.
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No page tables are created for the unused gaps.
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- The virtual memory regions are tracked or untracked by KASAN
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instrumentation, as well as the KASAN shadow memory itself is
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created only when CONFIG_KASAN configuration option is enabled.
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::
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=============================================================================
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| Physical | Virtual | VM area description
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=============================================================================
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+- 0 --------------+- 0 --------------+
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| | S390_lowcore | Low-address memory
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| +- 8 KB -----------+
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| | ... unused gap | KASAN untracked
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+- AMODE31_START --+- AMODE31_START --+ .amode31 rand. phys/virt start
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|.amode31 text/data|.amode31 text/data| KASAN untracked
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+- AMODE31_END ----+- AMODE31_END ----+ .amode31 rand. phys/virt end (<2GB)
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+- __kaslr_offset_phys | kernel rand. phys start
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| kernel text/data | |
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+------------------+ | kernel phys end
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+- ident_map_size -+ |
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| ... unused gap | KASAN untracked
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+- __identity_base + identity mapping start (>= 2GB)
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| identity | phys == virt - __identity_base
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| mapping | virt == phys + __identity_base
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| | KASAN tracked
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+---- vmemmap -----+ 'struct page' array start
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| virtually mapped |
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| memory map | KASAN untracked
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+- __abs_lowcore --+
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| Absolute Lowcore | KASAN untracked
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+- __memcpy_real_area
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| Real Memory Copy| KASAN untracked
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+- VMALLOC_START --+ vmalloc area start
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| | KASAN untracked or
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| vmalloc area | KASAN shallowly populated in case
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| | CONFIG_KASAN_VMALLOC=y
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+- MODULES_VADDR --+ modules area start
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| | KASAN allocated per module or
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| modules area | KASAN shallowly populated in case
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| | CONFIG_KASAN_VMALLOC=y
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+- __kaslr_offset -+ kernel rand. virt start
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| | KASAN tracked
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| kernel text/data | phys == (kvirt - __kaslr_offset) +
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| | __kaslr_offset_phys
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+- kernel .bss end + kernel rand. virt end
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| ... unused gap | KASAN untracked
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+------------------+ UltraVisor Secure Storage limit
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| ... unused gap | KASAN untracked
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+KASAN_SHADOW_START+ KASAN shadow memory start
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| KASAN shadow | KASAN untracked
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+------------------+ ASCE limit
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