forked from Minki/linux
7235db268a
32-bit version of sparc has three-level page tables and can use pgtable-nopud and folding of the upper layers. Replace usage of include/asm-generic/4level-fixup.h with include/asm-generic/pgtable-nopud.h and adjust page table manipulation macros and functions accordingly. Link: http://lkml.kernel.org/r/1572938135-31886-11-git-send-email-rppt@kernel.org Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: David S. Miller <davem@davemloft.net> Tested-by: Anatoly Pugachev <matorola@gmail.com> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greentime Hu <green.hu@gmail.com> Cc: Greg Ungerer <gerg@linux-m68k.org> Cc: Helge Deller <deller@gmx.de> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Mark Salter <msalter@redhat.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Michal Simek <monstr@monstr.eu> Cc: Peter Rosin <peda@axentia.se> Cc: Richard Weinberger <richard@nod.at> Cc: Rolf Eike Beer <eike-kernel@sf-tec.de> Cc: Russell King <linux@armlinux.org.uk> Cc: Russell King <rmk+kernel@armlinux.org.uk> Cc: Sam Creasey <sammy@sammy.net> Cc: Vincent Chen <deanbo422@gmail.com> Cc: Vineet Gupta <Vineet.Gupta1@synopsys.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
138 lines
3.1 KiB
C
138 lines
3.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* highmem.c: virtual kernel memory mappings for high memory
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*
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* Provides kernel-static versions of atomic kmap functions originally
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* found as inlines in include/asm-sparc/highmem.h. These became
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* needed as kmap_atomic() and kunmap_atomic() started getting
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* called from within modules.
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* -- Tomas Szepe <szepe@pinerecords.com>, September 2002
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*
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* But kmap_atomic() and kunmap_atomic() cannot be inlined in
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* modules because they are loaded with btfixup-ped functions.
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*/
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/*
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* The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
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* gives a more generic (and caching) interface. But kmap_atomic can
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* be used in IRQ contexts, so in some (very limited) cases we need it.
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*
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* XXX This is an old text. Actually, it's good to use atomic kmaps,
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* provided you remember that they are atomic and not try to sleep
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* with a kmap taken, much like a spinlock. Non-atomic kmaps are
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* shared by CPUs, and so precious, and establishing them requires IPI.
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* Atomic kmaps are lightweight and we may have NCPUS more of them.
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*/
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#include <linux/highmem.h>
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#include <linux/export.h>
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#include <linux/mm.h>
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#include <asm/cacheflush.h>
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#include <asm/tlbflush.h>
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#include <asm/pgalloc.h>
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#include <asm/vaddrs.h>
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pgprot_t kmap_prot;
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static pte_t *kmap_pte;
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void __init kmap_init(void)
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{
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unsigned long address;
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p4d_t *p4d;
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pud_t *pud;
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pmd_t *dir;
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address = __fix_to_virt(FIX_KMAP_BEGIN);
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p4d = p4d_offset(pgd_offset_k(address), address);
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pud = pud_offset(p4d, address);
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dir = pmd_offset(pud, address);
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/* cache the first kmap pte */
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kmap_pte = pte_offset_kernel(dir, address);
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kmap_prot = __pgprot(SRMMU_ET_PTE | SRMMU_PRIV | SRMMU_CACHE);
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}
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void *kmap_atomic(struct page *page)
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{
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unsigned long vaddr;
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long idx, type;
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preempt_disable();
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pagefault_disable();
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if (!PageHighMem(page))
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return page_address(page);
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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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/* XXX Fix - Anton */
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#if 0
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__flush_cache_one(vaddr);
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#else
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flush_cache_all();
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#endif
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#ifdef CONFIG_DEBUG_HIGHMEM
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BUG_ON(!pte_none(*(kmap_pte-idx)));
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#endif
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set_pte(kmap_pte-idx, mk_pte(page, kmap_prot));
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/* XXX Fix - Anton */
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#if 0
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__flush_tlb_one(vaddr);
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#else
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flush_tlb_all();
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#endif
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return (void*) vaddr;
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}
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EXPORT_SYMBOL(kmap_atomic);
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void __kunmap_atomic(void *kvaddr)
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{
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unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
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int type;
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if (vaddr < FIXADDR_START) { // FIXME
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pagefault_enable();
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preempt_enable();
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return;
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}
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type = kmap_atomic_idx();
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#ifdef CONFIG_DEBUG_HIGHMEM
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{
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unsigned long idx;
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idx = type + KM_TYPE_NR * smp_processor_id();
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BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN+idx));
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/* XXX Fix - Anton */
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#if 0
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__flush_cache_one(vaddr);
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#else
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flush_cache_all();
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#endif
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/*
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* force other mappings to Oops if they'll try to access
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* this pte without first remap it
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*/
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pte_clear(&init_mm, vaddr, kmap_pte-idx);
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/* XXX Fix - Anton */
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#if 0
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__flush_tlb_one(vaddr);
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#else
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flush_tlb_all();
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#endif
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}
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#endif
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kmap_atomic_idx_pop();
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pagefault_enable();
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preempt_enable();
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}
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EXPORT_SYMBOL(__kunmap_atomic);
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