da141706ae
Add page protections for arm64 similar to those in arm. This is for security reasons to prevent certain classes of exploits. The current method: - Map all memory as either RWX or RW. We round to the nearest section to avoid creating page tables before everything is mapped - Once everything is mapped, if either end of the RWX section should not be X, we split the PMD and remap as necessary - When initmem is to be freed, we change the permissions back to RW (using stop machine if necessary to flush the TLB) - If CONFIG_DEBUG_RODATA is set, the read only sections are set read only. Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Kees Cook <keescook@chromium.org> Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Laura Abbott <lauraa@codeaurora.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
160 lines
4.9 KiB
C
160 lines
4.9 KiB
C
/*
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* Based on arch/arm/include/asm/cacheflush.h
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*
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* Copyright (C) 1999-2002 Russell King.
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* Copyright (C) 2012 ARM Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef __ASM_CACHEFLUSH_H
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#define __ASM_CACHEFLUSH_H
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#include <linux/mm.h>
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/*
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* This flag is used to indicate that the page pointed to by a pte is clean
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* and does not require cleaning before returning it to the user.
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*/
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#define PG_dcache_clean PG_arch_1
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/*
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* MM Cache Management
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* ===================
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*
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* The arch/arm64/mm/cache.S implements these methods.
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*
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* Start addresses are inclusive and end addresses are exclusive; start
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* addresses should be rounded down, end addresses up.
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*
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* See Documentation/cachetlb.txt for more information. Please note that
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* the implementation assumes non-aliasing VIPT D-cache and (aliasing)
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* VIPT or ASID-tagged VIVT I-cache.
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*
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* flush_cache_all()
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*
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* Unconditionally clean and invalidate the entire cache.
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*
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* flush_cache_mm(mm)
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*
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* Clean and invalidate all user space cache entries
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* before a change of page tables.
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*
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* flush_icache_range(start, end)
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*
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* Ensure coherency between the I-cache and the D-cache in the
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* region described by start, end.
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* - start - virtual start address
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* - end - virtual end address
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*
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* __flush_cache_user_range(start, end)
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*
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* Ensure coherency between the I-cache and the D-cache in the
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* region described by start, end.
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* - start - virtual start address
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* - end - virtual end address
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*
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* __flush_dcache_area(kaddr, size)
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*
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* Ensure that the data held in page is written back.
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* - kaddr - page address
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* - size - region size
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*/
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extern void flush_cache_all(void);
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extern void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned long end);
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extern void flush_icache_range(unsigned long start, unsigned long end);
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extern void __flush_dcache_area(void *addr, size_t len);
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extern long __flush_cache_user_range(unsigned long start, unsigned long end);
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static inline void flush_cache_mm(struct mm_struct *mm)
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{
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}
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static inline void flush_cache_page(struct vm_area_struct *vma,
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unsigned long user_addr, unsigned long pfn)
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{
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}
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/*
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* Cache maintenance functions used by the DMA API. No to be used directly.
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*/
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extern void __dma_map_area(const void *, size_t, int);
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extern void __dma_unmap_area(const void *, size_t, int);
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extern void __dma_flush_range(const void *, const void *);
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/*
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* Copy user data from/to a page which is mapped into a different
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* processes address space. Really, we want to allow our "user
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* space" model to handle this.
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*/
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extern void copy_to_user_page(struct vm_area_struct *, struct page *,
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unsigned long, void *, const void *, unsigned long);
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#define copy_from_user_page(vma, page, vaddr, dst, src, len) \
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do { \
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memcpy(dst, src, len); \
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} while (0)
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#define flush_cache_dup_mm(mm) flush_cache_mm(mm)
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/*
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* flush_dcache_page is used when the kernel has written to the page
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* cache page at virtual address page->virtual.
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*
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* If this page isn't mapped (ie, page_mapping == NULL), or it might
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* have userspace mappings, then we _must_ always clean + invalidate
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* the dcache entries associated with the kernel mapping.
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*
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* Otherwise we can defer the operation, and clean the cache when we are
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* about to change to user space. This is the same method as used on SPARC64.
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* See update_mmu_cache for the user space part.
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*/
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#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
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extern void flush_dcache_page(struct page *);
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static inline void __flush_icache_all(void)
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{
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asm("ic ialluis");
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dsb(ish);
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}
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#define flush_dcache_mmap_lock(mapping) \
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spin_lock_irq(&(mapping)->tree_lock)
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#define flush_dcache_mmap_unlock(mapping) \
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spin_unlock_irq(&(mapping)->tree_lock)
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/*
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* We don't appear to need to do anything here. In fact, if we did, we'd
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* duplicate cache flushing elsewhere performed by flush_dcache_page().
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*/
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#define flush_icache_page(vma,page) do { } while (0)
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/*
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* Not required on AArch64 (PIPT or VIPT non-aliasing D-cache).
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*/
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static inline void flush_cache_vmap(unsigned long start, unsigned long end)
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{
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}
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static inline void flush_cache_vunmap(unsigned long start, unsigned long end)
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{
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}
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int set_memory_ro(unsigned long addr, int numpages);
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int set_memory_rw(unsigned long addr, int numpages);
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int set_memory_x(unsigned long addr, int numpages);
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int set_memory_nx(unsigned long addr, int numpages);
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#ifdef CONFIG_DEBUG_RODATA
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void mark_rodata_ro(void);
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#endif
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#endif
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