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https://github.com/torvalds/linux
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2fb410596c
After the HYP page table rework, it is pretty easy to let the KVM code provide its own idmap, rather than expecting the kernel to provide it. It takes actually less code to do so. Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu>
124 lines
3 KiB
C
124 lines
3 KiB
C
#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 <asm/cputype.h>
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#include <asm/idmap.h>
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#include <asm/pgalloc.h>
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#include <asm/pgtable.h>
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#include <asm/sections.h>
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#include <asm/system_info.h>
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pgd_t *idmap_pgd;
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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_warning("Failed to allocate identity pmd.\n");
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return;
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}
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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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pud_t *pud = pud_offset(pgd, 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_phys(text_start);
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end = virt_to_phys(text_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())
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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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pr_info("Setting up static identity map for 0x%p - 0x%p\n",
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__idmap_text_start, __idmap_text_end);
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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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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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