forked from Minki/linux
Revert "arm64: Mark kernel page ranges contiguous"
This reverts commit 348a65cdcb
.
Incorrect page table manipulation that does not respect the ARM ARM
recommended break-before-make sequence may lead to TLB conflicts. The
contiguous PTE patch makes the system even more susceptible to such
errors by changing the mapping from a single page to a contiguous range
of pages. An additional TLB invalidation would reduce the risk window,
however, the correct fix is to switch to a temporary swapper_pg_dir.
Once the correct workaround is done, the reverted commit will be
re-applied.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Jeremy Linton <jeremy.linton@arm.com>
This commit is contained in:
parent
0ebea80880
commit
667c27597c
@ -85,55 +85,19 @@ static void split_pmd(pmd_t *pmd, pte_t *pte)
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do {
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/*
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* Need to have the least restrictive permissions available
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* permissions will be fixed up later. Default the new page
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* range as contiguous ptes.
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* permissions will be fixed up later
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*/
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set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC_CONT));
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set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
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pfn++;
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} while (pte++, i++, i < PTRS_PER_PTE);
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}
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/*
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* Given a PTE with the CONT bit set, determine where the CONT range
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* starts, and clear the entire range of PTE CONT bits.
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*/
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static void clear_cont_pte_range(pte_t *pte, unsigned long addr)
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{
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int i;
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pte -= CONT_RANGE_OFFSET(addr);
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for (i = 0; i < CONT_PTES; i++) {
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set_pte(pte, pte_mknoncont(*pte));
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pte++;
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}
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flush_tlb_all();
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}
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/*
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* Given a range of PTEs set the pfn and provided page protection flags
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*/
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static void __populate_init_pte(pte_t *pte, unsigned long addr,
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unsigned long end, phys_addr_t phys,
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pgprot_t prot)
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{
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unsigned long pfn = __phys_to_pfn(phys);
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do {
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/* clear all the bits except the pfn, then apply the prot */
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set_pte(pte, pfn_pte(pfn, prot));
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pte++;
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pfn++;
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addr += PAGE_SIZE;
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} while (addr != end);
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}
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static void alloc_init_pte(pmd_t *pmd, unsigned long addr,
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unsigned long end, phys_addr_t phys,
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unsigned long end, unsigned long pfn,
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pgprot_t prot,
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void *(*alloc)(unsigned long size))
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{
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pte_t *pte;
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unsigned long next;
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if (pmd_none(*pmd) || pmd_sect(*pmd)) {
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pte = alloc(PTRS_PER_PTE * sizeof(pte_t));
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@ -146,27 +110,9 @@ static void alloc_init_pte(pmd_t *pmd, unsigned long addr,
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pte = pte_offset_kernel(pmd, addr);
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do {
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next = min(end, (addr + CONT_SIZE) & CONT_MASK);
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if (((addr | next | phys) & ~CONT_MASK) == 0) {
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/* a block of CONT_PTES */
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__populate_init_pte(pte, addr, next, phys,
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__pgprot(pgprot_val(prot) | PTE_CONT));
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} else {
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/*
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* If the range being split is already inside of a
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* contiguous range but this PTE isn't going to be
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* contiguous, then we want to unmark the adjacent
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* ranges, then update the portion of the range we
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* are interrested in.
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*/
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clear_cont_pte_range(pte, addr);
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__populate_init_pte(pte, addr, next, phys, prot);
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}
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pte += (next - addr) >> PAGE_SHIFT;
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phys += next - addr;
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addr = next;
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} while (addr != end);
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set_pte(pte, pfn_pte(pfn, prot));
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pfn++;
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} while (pte++, addr += PAGE_SIZE, addr != end);
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}
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static void split_pud(pud_t *old_pud, pmd_t *pmd)
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@ -227,7 +173,8 @@ static void alloc_init_pmd(struct mm_struct *mm, pud_t *pud,
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}
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}
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} else {
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alloc_init_pte(pmd, addr, next, phys, prot, alloc);
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alloc_init_pte(pmd, addr, next, __phys_to_pfn(phys),
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prot, alloc);
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}
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phys += next - addr;
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} while (pmd++, addr = next, addr != end);
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