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96d4f267e4
Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.
It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access. But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.
A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model. And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.
This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.
There were a couple of notable cases:
- csky still had the old "verify_area()" name as an alias.
- the iter_iov code had magical hardcoded knowledge of the actual
values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
really used it)
- microblaze used the type argument for a debug printout
but other than those oddities this should be a total no-op patch.
I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something. Any missed conversion should be trivially fixable, though.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
112 lines
3.1 KiB
C
112 lines
3.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_X86_PGTABLE_32_H
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#define _ASM_X86_PGTABLE_32_H
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#include <asm/pgtable_32_types.h>
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/*
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* The Linux memory management assumes a three-level page table setup. On
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* the i386, we use that, but "fold" the mid level into the top-level page
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* table, so that we physically have the same two-level page table as the
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* i386 mmu expects.
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*
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* This file contains the functions and defines necessary to modify and use
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* the i386 page table tree.
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*/
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#ifndef __ASSEMBLY__
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#include <asm/processor.h>
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#include <linux/threads.h>
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#include <asm/paravirt.h>
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#include <linux/bitops.h>
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#include <linux/list.h>
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#include <linux/spinlock.h>
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struct mm_struct;
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struct vm_area_struct;
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extern pgd_t swapper_pg_dir[1024];
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extern pgd_t initial_page_table[1024];
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extern pmd_t initial_pg_pmd[];
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static inline void pgtable_cache_init(void) { }
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static inline void check_pgt_cache(void) { }
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void paging_init(void);
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void sync_initial_page_table(void);
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/*
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* Define this if things work differently on an i386 and an i486:
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* it will (on an i486) warn about kernel memory accesses that are
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* done without a 'access_ok( ..)'
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*/
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#undef TEST_ACCESS_OK
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#ifdef CONFIG_X86_PAE
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# include <asm/pgtable-3level.h>
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#else
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# include <asm/pgtable-2level.h>
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#endif
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#if defined(CONFIG_HIGHPTE)
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#define pte_offset_map(dir, address) \
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((pte_t *)kmap_atomic(pmd_page(*(dir))) + \
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pte_index((address)))
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#define pte_unmap(pte) kunmap_atomic((pte))
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#else
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#define pte_offset_map(dir, address) \
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((pte_t *)page_address(pmd_page(*(dir))) + pte_index((address)))
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#define pte_unmap(pte) do { } while (0)
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#endif
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/* Clear a kernel PTE and flush it from the TLB */
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#define kpte_clear_flush(ptep, vaddr) \
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do { \
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pte_clear(&init_mm, (vaddr), (ptep)); \
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__flush_tlb_one_kernel((vaddr)); \
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} while (0)
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#endif /* !__ASSEMBLY__ */
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/*
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* kern_addr_valid() is (1) for FLATMEM and (0) for
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* SPARSEMEM and DISCONTIGMEM
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*/
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#ifdef CONFIG_FLATMEM
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#define kern_addr_valid(addr) (1)
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#else
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#define kern_addr_valid(kaddr) (0)
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#endif
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/*
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* This is how much memory in addition to the memory covered up to
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* and including _end we need mapped initially.
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* We need:
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* (KERNEL_IMAGE_SIZE/4096) / 1024 pages (worst case, non PAE)
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* (KERNEL_IMAGE_SIZE/4096) / 512 + 4 pages (worst case for PAE)
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*
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* Modulo rounding, each megabyte assigned here requires a kilobyte of
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* memory, which is currently unreclaimed.
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*
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* This should be a multiple of a page.
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*
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* KERNEL_IMAGE_SIZE should be greater than pa(_end)
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* and small than max_low_pfn, otherwise will waste some page table entries
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*/
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#if PTRS_PER_PMD > 1
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#define PAGE_TABLE_SIZE(pages) (((pages) / PTRS_PER_PMD) + PTRS_PER_PGD)
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#else
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#define PAGE_TABLE_SIZE(pages) ((pages) / PTRS_PER_PGD)
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#endif
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/*
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* Number of possible pages in the lowmem region.
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*
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* We shift 2 by 31 instead of 1 by 32 to the left in order to avoid a
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* gas warning about overflowing shift count when gas has been compiled
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* with only a host target support using a 32-bit type for internal
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* representation.
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*/
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#define LOWMEM_PAGES ((((2<<31) - __PAGE_OFFSET) >> PAGE_SHIFT))
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#endif /* _ASM_X86_PGTABLE_32_H */
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