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The documented semantics of flush_cache_all are not possible to provide for arm64 (short of flushing the entire physical address space by VA), and there are currently no users; KVM uses VA maintenance exclusively, cpu_reset is never called, and the only two users outside of arch code cannot be built for arm64. While cpu_soft_reset and related functions (which call flush_cache_all) were thought to be useful for kexec, their current implementations only serve to mask bugs. For correctness kexec will need to perform maintenance by VA anyway to account for system caches, line migration, and other subtleties of the cache architecture. As the extent of this cache maintenance will be kexec-specific, it should probably live in the kexec code. This patch removes flush_cache_all, and related unused components, preventing further abuse. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: AKASHI Takahiro <takahiro.akashi@linaro.org> Cc: Geoff Levand <geoff@infradead.org> Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
122 lines
3.2 KiB
C
122 lines
3.2 KiB
C
/*
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* Based on arch/arm/mm/flush.c
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*
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* Copyright (C) 1995-2002 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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#include <linux/export.h>
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#include <linux/mm.h>
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#include <linux/pagemap.h>
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#include <asm/cacheflush.h>
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#include <asm/cachetype.h>
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#include <asm/tlbflush.h>
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#include "mm.h"
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void flush_cache_range(struct vm_area_struct *vma, unsigned long start,
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unsigned long end)
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{
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if (vma->vm_flags & VM_EXEC)
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__flush_icache_all();
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}
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static void flush_ptrace_access(struct vm_area_struct *vma, struct page *page,
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unsigned long uaddr, void *kaddr,
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unsigned long len)
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{
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if (vma->vm_flags & VM_EXEC) {
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unsigned long addr = (unsigned long)kaddr;
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if (icache_is_aliasing()) {
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__flush_dcache_area(kaddr, len);
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__flush_icache_all();
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} else {
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flush_icache_range(addr, addr + len);
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}
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}
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}
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/*
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* Copy user data from/to a page which is mapped into a different processes
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* address space. Really, we want to allow our "user space" model to handle
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* this.
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*
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* Note that this code needs to run on the current CPU.
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*/
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void copy_to_user_page(struct vm_area_struct *vma, struct page *page,
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unsigned long uaddr, void *dst, const void *src,
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unsigned long len)
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{
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#ifdef CONFIG_SMP
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preempt_disable();
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#endif
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memcpy(dst, src, len);
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flush_ptrace_access(vma, page, uaddr, dst, len);
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#ifdef CONFIG_SMP
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preempt_enable();
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#endif
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}
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void __sync_icache_dcache(pte_t pte, unsigned long addr)
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{
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struct page *page = pte_page(pte);
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/* no flushing needed for anonymous pages */
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if (!page_mapping(page))
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return;
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if (!test_and_set_bit(PG_dcache_clean, &page->flags)) {
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__flush_dcache_area(page_address(page),
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PAGE_SIZE << compound_order(page));
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__flush_icache_all();
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} else if (icache_is_aivivt()) {
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__flush_icache_all();
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}
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}
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/*
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* This function is called when a page has been modified by the kernel. Mark
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* it as dirty for later flushing when mapped in user space (if executable,
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* see __sync_icache_dcache).
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*/
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void flush_dcache_page(struct page *page)
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{
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if (test_bit(PG_dcache_clean, &page->flags))
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clear_bit(PG_dcache_clean, &page->flags);
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}
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EXPORT_SYMBOL(flush_dcache_page);
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/*
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* Additional functions defined in assembly.
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*/
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EXPORT_SYMBOL(flush_icache_range);
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#ifdef CONFIG_TRANSPARENT_HUGEPAGE
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#ifdef CONFIG_HAVE_RCU_TABLE_FREE
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void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
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pmd_t *pmdp)
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{
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pmd_t pmd = pmd_mksplitting(*pmdp);
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VM_BUG_ON(address & ~PMD_MASK);
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set_pmd_at(vma->vm_mm, address, pmdp, pmd);
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/* dummy IPI to serialise against fast_gup */
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kick_all_cpus_sync();
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}
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#endif /* CONFIG_HAVE_RCU_TABLE_FREE */
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#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
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