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e16e65a029
When CONFIG_DEBUG_ALIGN_RODATA is enabled, kernel segments mapped with different permissions (r-x for .text, r-- for .rodata, rw- for .data, etc) are rounded up to 2 MiB so they can be mapped more efficiently. In particular, it permits the segments to be mapped using level 2 block entries when using 4k pages, which is expected to result in less TLB pressure. However, the mappings for the bulk of the kernel will use level 2 entries anyway, and the misaligned fringes are organized such that they can take advantage of the contiguous bit, and use far fewer level 3 entries than would be needed otherwise. This makes the value of this feature dubious at best, and since it is not enabled in defconfig or in the distro configs, it does not appear to be in wide use either. So let's just remove it. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Will Deacon <will@kernel.org> Acked-by: Laura Abbott <labbott@kernel.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
67 lines
2.3 KiB
Text
67 lines
2.3 KiB
Text
# SPDX-License-Identifier: GPL-2.0-only
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config PID_IN_CONTEXTIDR
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bool "Write the current PID to the CONTEXTIDR register"
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help
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Enabling this option causes the kernel to write the current PID to
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the CONTEXTIDR register, at the expense of some additional
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instructions during context switch. Say Y here only if you are
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planning to use hardware trace tools with this kernel.
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config ARM64_RANDOMIZE_TEXT_OFFSET
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bool "Randomize TEXT_OFFSET at build time"
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help
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Say Y here if you want the image load offset (AKA TEXT_OFFSET)
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of the kernel to be randomized at build-time. When selected,
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this option will cause TEXT_OFFSET to be randomized upon any
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build of the kernel, and the offset will be reflected in the
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text_offset field of the resulting Image. This can be used to
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fuzz-test bootloaders which respect text_offset.
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This option is intended for bootloader and/or kernel testing
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only. Bootloaders must make no assumptions regarding the value
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of TEXT_OFFSET and platforms must not require a specific
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value.
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config DEBUG_WX
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bool "Warn on W+X mappings at boot"
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select PTDUMP_CORE
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---help---
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Generate a warning if any W+X mappings are found at boot.
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This is useful for discovering cases where the kernel is leaving
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W+X mappings after applying NX, as such mappings are a security risk.
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This check also includes UXN, which should be set on all kernel
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mappings.
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Look for a message in dmesg output like this:
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arm64/mm: Checked W+X mappings: passed, no W+X pages found.
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or like this, if the check failed:
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arm64/mm: Checked W+X mappings: FAILED, <N> W+X pages found.
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Note that even if the check fails, your kernel is possibly
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still fine, as W+X mappings are not a security hole in
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themselves, what they do is that they make the exploitation
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of other unfixed kernel bugs easier.
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There is no runtime or memory usage effect of this option
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once the kernel has booted up - it's a one time check.
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If in doubt, say "Y".
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config DEBUG_EFI
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depends on EFI && DEBUG_INFO
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bool "UEFI debugging"
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help
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Enable this option to include EFI specific debugging features into
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the kernel that are only useful when using a debug build of the
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UEFI firmware
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config ARM64_RELOC_TEST
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depends on m
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tristate "Relocation testing module"
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source "drivers/hwtracing/coresight/Kconfig"
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