536788fe2d
Calculate TASK_SIZE at run-time by figuring out the host's VMSPLIT - this is needed on i386 if UML is to run on hosts with varying VMSPLITs without recompilation. TASK_SIZE is now defined in terms of a variable, task_size. This gets rid of an include of pgtable.h from processor.h, which can cause include loops. On i386, task_size is calculated early in boot by probing the address space in a binary search to figure out where the boundary between usable and non-usable memory is. This tries to make sure that a page that is considered to be in userspace is, or can be made, read-write. I'm concerned about a system-global VDSO page in kernel memory being hit and considered to be a userspace page. On x86_64, task_size is just the old value of CONFIG_TOP_ADDR. A bunch of config variable are gone now. CONFIG_TOP_ADDR is directly replaced by TASK_SIZE. NEST_LEVEL is gone since the relocation of the stubs makes it irrelevant. All the HOST_VMSPLIT stuff is gone. All references to these in arch/um/Makefile are also gone. I noticed and fixed a missing extern in os.h when adding os_get_task_size. Note: This has been revised to fix the 32-bit UML on 64-bit host bug that Miklos ran into. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
51 lines
870 B
Text
51 lines
870 B
Text
menu "Host processor type and features"
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source "arch/x86/Kconfig.cpu"
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endmenu
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config UML_X86
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bool
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default y
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config X86_32
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bool
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default y
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config RWSEM_XCHGADD_ALGORITHM
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def_bool y
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config 64BIT
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bool
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default n
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config SEMAPHORE_SLEEPERS
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bool
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default y
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config 3_LEVEL_PGTABLES
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bool "Three-level pagetables (EXPERIMENTAL)"
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default n
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depends on EXPERIMENTAL
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help
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Three-level pagetables will let UML have more than 4G of physical
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memory. All the memory that can't be mapped directly will be treated
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as high memory.
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However, this it experimental on 32-bit architectures, so if unsure say
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N (on x86-64 it's automatically enabled, instead, as it's safe there).
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config ARCH_HAS_SC_SIGNALS
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bool
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default y
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config ARCH_REUSE_HOST_VSYSCALL_AREA
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bool
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default y
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config GENERIC_HWEIGHT
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bool
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default y
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config ARCH_SUPPORTS_AOUT
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def_bool y
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