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https://github.com/edk2-porting/linux-next.git
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af3813d6a5
Remove some knowledge of our 2-level page table layout from the identity mapping code - we assume that a step size of PGDIR_SIZE will allow us to step over all entries. While this is true today, it won't be true in the near future. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
68 lines
1.6 KiB
C
68 lines
1.6 KiB
C
#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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static void idmap_add_pmd(pgd_t *pgd, unsigned long addr, unsigned long end,
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unsigned long prot)
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{
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pmd_t *pmd = pmd_offset(pgd, addr);
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addr = (addr & PMD_MASK) | prot;
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pmd[0] = __pmd(addr);
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addr += SECTION_SIZE;
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pmd[1] = __pmd(addr);
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flush_pmd_entry(pmd);
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}
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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, next;
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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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pgd += pgd_index(addr);
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do {
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next = pgd_addr_end(addr, end);
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idmap_add_pmd(pgd, addr, next, prot);
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} while (pgd++, addr = next, addr != end);
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}
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#ifdef CONFIG_SMP
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static void idmap_del_pmd(pgd_t *pgd, unsigned long addr, unsigned long end)
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{
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pmd_t *pmd = pmd_offset(pgd, addr);
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pmd_clear(pmd);
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}
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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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unsigned long next;
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pgd += pgd_index(addr);
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do {
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next = pgd_addr_end(addr, end);
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idmap_del_pmd(pgd, addr, next);
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} while (pgd++, addr = next, addr != end);
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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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