mirror of https://gitee.com/openkylin/linux.git
52 lines
1.3 KiB
C
52 lines
1.3 KiB
C
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#include <linux/kernel.h>
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#include <asm/cputype.h>
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#include <asm/pgalloc.h>
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#include <asm/pgtable.h>
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void identity_mapping_add(pgd_t *pgd, unsigned long addr, unsigned long end)
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{
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unsigned long prot;
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prot = PMD_TYPE_SECT | PMD_SECT_AP_WRITE;
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if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale())
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prot |= PMD_BIT4;
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for (addr &= PGDIR_MASK; addr < end;) {
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pmd_t *pmd = pmd_offset(pgd + pgd_index(addr), addr);
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pmd[0] = __pmd(addr | prot);
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addr += SECTION_SIZE;
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pmd[1] = __pmd(addr | prot);
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addr += SECTION_SIZE;
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flush_pmd_entry(pmd);
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}
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}
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#ifdef CONFIG_SMP
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void identity_mapping_del(pgd_t *pgd, unsigned long addr, unsigned long end)
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{
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for (addr &= PGDIR_MASK; addr < end; addr += PGDIR_SIZE) {
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pmd_t *pmd = pmd_offset(pgd + pgd_index(addr), addr);
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pmd[0] = __pmd(0);
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pmd[1] = __pmd(0);
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clean_pmd_entry(pmd);
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}
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}
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#endif
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/*
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* In order to soft-boot, we need to insert a 1:1 mapping in place of
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* the user-mode pages. This will then ensure that we have predictable
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* results when turning the mmu off
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*/
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void setup_mm_for_reboot(char mode)
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{
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/*
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* We need to access to user-mode page tables here. For kernel threads
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* we don't have any user-mode mappings so we use the context that we
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* "borrowed".
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*/
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identity_mapping_add(current->active_mm->pgd, 0, TASK_SIZE);
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local_flush_tlb_all();
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}
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