![Dave Hansen](/assets/img/avatar_default.png)
A PTE is constructed from a physical address and a pgprotval_t. __PAGE_KERNEL, for instance, is a pgprot_t and must be converted into a pgprotval_t before it can be used to create a PTE. This is done implicitly within functions like pfn_pte() by massage_pgprot(). However, this makes it very challenging to set bits (and keep them set) if your bit is being filtered out by massage_pgprot(). This moves the bit filtering out of pfn_pte() and friends. For users of PAGE_KERNEL*, filtering will be done automatically inside those macros but for users of __PAGE_KERNEL*, they need to do their own filtering now. Note that we also just move pfn_pte/pmd/pud() over to check_pgprot() instead of massage_pgprot(). This way, we still *look* for unsupported bits and properly warn about them if we find them. This might happen if an unfiltered __PAGE_KERNEL* value was passed in, for instance. - printk format warning fix from: Arnd Bergmann <arnd@arndb.de> - boot crash fix from: Tom Lendacky <thomas.lendacky@amd.com> - crash bisected by: Mike Galbraith <efault@gmx.de> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reported-and-fixed-by: Arnd Bergmann <arnd@arndb.de> Fixed-by: Tom Lendacky <thomas.lendacky@amd.com> Bisected-by: Mike Galbraith <efault@gmx.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Hugh Dickins <hughd@google.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Kees Cook <keescook@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nadav Amit <namit@vmware.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20180406205509.77E1D7F6@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
130 lines
3.7 KiB
C
130 lines
3.7 KiB
C
/*
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* Copyright © 2008 Ingo Molnar
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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 as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* 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 along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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*/
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#include <asm/iomap.h>
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#include <asm/pat.h>
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#include <linux/export.h>
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#include <linux/highmem.h>
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static int is_io_mapping_possible(resource_size_t base, unsigned long size)
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{
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#if !defined(CONFIG_X86_PAE) && defined(CONFIG_PHYS_ADDR_T_64BIT)
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/* There is no way to map greater than 1 << 32 address without PAE */
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if (base + size > 0x100000000ULL)
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return 0;
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#endif
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return 1;
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}
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int iomap_create_wc(resource_size_t base, unsigned long size, pgprot_t *prot)
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{
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enum page_cache_mode pcm = _PAGE_CACHE_MODE_WC;
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int ret;
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if (!is_io_mapping_possible(base, size))
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return -EINVAL;
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ret = io_reserve_memtype(base, base + size, &pcm);
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if (ret)
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return ret;
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*prot = __pgprot(__PAGE_KERNEL | cachemode2protval(pcm));
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/* Filter out unsupported __PAGE_KERNEL* bits: */
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pgprot_val(*prot) &= __default_kernel_pte_mask;
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return 0;
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}
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EXPORT_SYMBOL_GPL(iomap_create_wc);
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void iomap_free(resource_size_t base, unsigned long size)
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{
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io_free_memtype(base, base + size);
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}
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EXPORT_SYMBOL_GPL(iomap_free);
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void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot)
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{
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unsigned long vaddr;
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int idx, type;
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preempt_disable();
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pagefault_disable();
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type = kmap_atomic_idx_push();
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idx = type + KM_TYPE_NR * smp_processor_id();
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vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
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set_pte(kmap_pte - idx, pfn_pte(pfn, prot));
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arch_flush_lazy_mmu_mode();
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return (void *)vaddr;
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}
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/*
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* Map 'pfn' using protections 'prot'
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*/
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void __iomem *
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iomap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot)
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{
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/*
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* For non-PAT systems, translate non-WB request to UC- just in
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* case the caller set the PWT bit to prot directly without using
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* pgprot_writecombine(). UC- translates to uncached if the MTRR
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* is UC or WC. UC- gets the real intention, of the user, which is
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* "WC if the MTRR is WC, UC if you can't do that."
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*/
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if (!pat_enabled() && pgprot2cachemode(prot) != _PAGE_CACHE_MODE_WB)
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prot = __pgprot(__PAGE_KERNEL |
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cachemode2protval(_PAGE_CACHE_MODE_UC_MINUS));
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/* Filter out unsupported __PAGE_KERNEL* bits: */
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pgprot_val(prot) &= __default_kernel_pte_mask;
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return (void __force __iomem *) kmap_atomic_prot_pfn(pfn, prot);
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}
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EXPORT_SYMBOL_GPL(iomap_atomic_prot_pfn);
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void
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iounmap_atomic(void __iomem *kvaddr)
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{
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unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
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if (vaddr >= __fix_to_virt(FIX_KMAP_END) &&
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vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) {
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int idx, type;
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type = kmap_atomic_idx();
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idx = type + KM_TYPE_NR * smp_processor_id();
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#ifdef CONFIG_DEBUG_HIGHMEM
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WARN_ON_ONCE(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
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#endif
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/*
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* Force other mappings to Oops if they'll try to access this
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* pte without first remap it. Keeping stale mappings around
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* is a bad idea also, in case the page changes cacheability
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* attributes or becomes a protected page in a hypervisor.
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*/
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kpte_clear_flush(kmap_pte-idx, vaddr);
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kmap_atomic_idx_pop();
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}
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pagefault_enable();
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preempt_enable();
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}
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EXPORT_SYMBOL_GPL(iounmap_atomic);
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