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141 lines
3.5 KiB
141 lines
3.5 KiB
// SPDX-License-Identifier: GPL-2.0 |
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#include <linux/module.h> |
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#include <linux/kernel.h> |
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#include <linux/slab.h> |
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#include <linux/mm_types.h> |
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#include <linux/pgtable.h> |
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#include <asm/cputype.h> |
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#include <asm/idmap.h> |
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#include <asm/hwcap.h> |
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#include <asm/pgalloc.h> |
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#include <asm/sections.h> |
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#include <asm/system_info.h> |
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/* |
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* Note: accesses outside of the kernel image and the identity map area |
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* are not supported on any CPU using the idmap tables as its current |
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* page tables. |
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*/ |
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pgd_t *idmap_pgd __ro_after_init; |
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long long arch_phys_to_idmap_offset __ro_after_init; |
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#ifdef CONFIG_ARM_LPAE |
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static void idmap_add_pmd(pud_t *pud, unsigned long addr, unsigned long end, |
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unsigned long prot) |
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{ |
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pmd_t *pmd; |
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unsigned long next; |
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if (pud_none_or_clear_bad(pud) || (pud_val(*pud) & L_PGD_SWAPPER)) { |
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pmd = pmd_alloc_one(&init_mm, addr); |
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if (!pmd) { |
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pr_warn("Failed to allocate identity pmd.\n"); |
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return; |
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} |
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/* |
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* Copy the original PMD to ensure that the PMD entries for |
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* the kernel image are preserved. |
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*/ |
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if (!pud_none(*pud)) |
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memcpy(pmd, pmd_offset(pud, 0), |
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PTRS_PER_PMD * sizeof(pmd_t)); |
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pud_populate(&init_mm, pud, pmd); |
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pmd += pmd_index(addr); |
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} else |
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pmd = pmd_offset(pud, addr); |
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do { |
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next = pmd_addr_end(addr, end); |
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*pmd = __pmd((addr & PMD_MASK) | prot); |
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flush_pmd_entry(pmd); |
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} while (pmd++, addr = next, addr != end); |
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} |
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#else /* !CONFIG_ARM_LPAE */ |
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static void idmap_add_pmd(pud_t *pud, 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(pud, 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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#endif /* CONFIG_ARM_LPAE */ |
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static void idmap_add_pud(pgd_t *pgd, unsigned long addr, unsigned long end, |
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unsigned long prot) |
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{ |
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p4d_t *p4d = p4d_offset(pgd, addr); |
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pud_t *pud = pud_offset(p4d, addr); |
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unsigned long next; |
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do { |
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next = pud_addr_end(addr, end); |
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idmap_add_pmd(pud, addr, next, prot); |
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} while (pud++, addr = next, addr != end); |
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} |
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static void identity_mapping_add(pgd_t *pgd, const char *text_start, |
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const char *text_end, unsigned long prot) |
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{ |
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unsigned long addr, end; |
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unsigned long next; |
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addr = virt_to_idmap(text_start); |
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end = virt_to_idmap(text_end); |
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pr_info("Setting up static identity map for 0x%lx - 0x%lx\n", addr, end); |
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prot |= PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_SECT_AF; |
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if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale_family()) |
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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_pud(pgd, addr, next, prot); |
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} while (pgd++, addr = next, addr != end); |
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} |
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extern char __idmap_text_start[], __idmap_text_end[]; |
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static int __init init_static_idmap(void) |
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{ |
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idmap_pgd = pgd_alloc(&init_mm); |
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if (!idmap_pgd) |
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return -ENOMEM; |
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identity_mapping_add(idmap_pgd, __idmap_text_start, |
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__idmap_text_end, 0); |
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/* Flush L1 for the hardware to see this page table content */ |
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if (!(elf_hwcap & HWCAP_LPAE)) |
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flush_cache_louis(); |
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return 0; |
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} |
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early_initcall(init_static_idmap); |
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/* |
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* In order to soft-boot, we need to switch to a 1:1 mapping for the |
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* cpu_reset functions. This will then ensure that we have predictable |
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* results when turning off the mmu. |
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*/ |
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void setup_mm_for_reboot(void) |
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{ |
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/* Switch to the identity mapping. */ |
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cpu_switch_mm(idmap_pgd, &init_mm); |
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local_flush_bp_all(); |
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#ifdef CONFIG_CPU_HAS_ASID |
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/* |
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* We don't have a clean ASID for the identity mapping, which |
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* may clash with virtual addresses of the previous page tables |
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* and therefore potentially in the TLB. |
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*/ |
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local_flush_tlb_all(); |
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#endif |
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}
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