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981b6714db
For kexec, we need more functionality from the IDMAP system. We need to be able to convert physical addresses to their identity mappped versions as well as virtual addresses. Convert the existing arch_virt_to_idmap() to deal with physical addresses instead. Acked-by: Santosh Shilimkar <ssantosh@kernel.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
137 lines
3.4 KiB
C
137 lines
3.4 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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/*
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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;
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long long arch_phys_to_idmap_offset;
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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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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_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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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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