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>
98 lines
3 KiB
C
98 lines
3 KiB
C
#ifndef __UM_FIXMAP_H
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#define __UM_FIXMAP_H
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#include <asm/processor.h>
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#include <asm/system.h>
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#include <asm/kmap_types.h>
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#include <asm/archparam.h>
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#include <asm/page.h>
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/*
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* Here we define all the compile-time 'special' virtual
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* addresses. The point is to have a constant address at
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* compile time, but to set the physical address only
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* in the boot process. We allocate these special addresses
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* from the end of virtual memory (0xfffff000) backwards.
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* Also this lets us do fail-safe vmalloc(), we
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* can guarantee that these special addresses and
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* vmalloc()-ed addresses never overlap.
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*
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* these 'compile-time allocated' memory buffers are
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* fixed-size 4k pages. (or larger if used with an increment
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* highger than 1) use fixmap_set(idx,phys) to associate
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* physical memory with fixmap indices.
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*
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* TLB entries of such buffers will not be flushed across
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* task switches.
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*/
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/*
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* on UP currently we will have no trace of the fixmap mechanizm,
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* no page table allocations, etc. This might change in the
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* future, say framebuffers for the console driver(s) could be
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* fix-mapped?
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*/
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enum fixed_addresses {
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#ifdef CONFIG_HIGHMEM
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FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
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FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
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#endif
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__end_of_fixed_addresses
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};
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extern void __set_fixmap (enum fixed_addresses idx,
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unsigned long phys, pgprot_t flags);
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#define set_fixmap(idx, phys) \
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__set_fixmap(idx, phys, PAGE_KERNEL)
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/*
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* Some hardware wants to get fixmapped without caching.
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*/
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#define set_fixmap_nocache(idx, phys) \
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__set_fixmap(idx, phys, PAGE_KERNEL_NOCACHE)
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/*
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* used by vmalloc.c.
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*
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* Leave one empty page between vmalloc'ed areas and
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* the start of the fixmap, and leave one page empty
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* at the top of mem..
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*/
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#define FIXADDR_TOP (TASK_SIZE - 2 * PAGE_SIZE)
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#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
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#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
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#define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
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#define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
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extern void __this_fixmap_does_not_exist(void);
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/*
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* 'index to address' translation. If anyone tries to use the idx
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* directly without tranlation, we catch the bug with a NULL-deference
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* kernel oops. Illegal ranges of incoming indices are caught too.
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*/
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static inline unsigned long fix_to_virt(const unsigned int idx)
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{
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/*
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* this branch gets completely eliminated after inlining,
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* except when someone tries to use fixaddr indices in an
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* illegal way. (such as mixing up address types or using
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* out-of-range indices).
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*
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* If it doesn't get removed, the linker will complain
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* loudly with a reasonably clear error message..
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*/
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if (idx >= __end_of_fixed_addresses)
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__this_fixmap_does_not_exist();
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return __fix_to_virt(idx);
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}
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static inline unsigned long virt_to_fix(const unsigned long vaddr)
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{
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BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
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return __virt_to_fix(vaddr);
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}
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#endif
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