arm64: Factor out fixmap initialization from ioremap

[cascardo/linux.git] / arch / arm64 / mm / mmu.c

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index f4f8b50..6032f3e 100644 (file)
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -28,6 +28,7 @@
 #include <linux/io.h>
 
 #include <asm/cputype.h>
+#include <asm/fixmap.h>
 #include <asm/sections.h>
 #include <asm/setup.h>
 #include <asm/sizes.h>
@@ -463,3 +464,96 @@ void vmemmap_free(unsigned long start, unsigned long end)
 {
 }
 #endif /* CONFIG_SPARSEMEM_VMEMMAP */
+
+static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss;
+#if CONFIG_ARM64_PGTABLE_LEVELS > 2
+static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss;
+#endif
+#if CONFIG_ARM64_PGTABLE_LEVELS > 3
+static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss;
+#endif
+
+static inline pud_t * fixmap_pud(unsigned long addr)
+{
+       pgd_t *pgd = pgd_offset_k(addr);
+
+       BUG_ON(pgd_none(*pgd) || pgd_bad(*pgd));
+
+       return pud_offset(pgd, addr);
+}
+
+static inline pmd_t * fixmap_pmd(unsigned long addr)
+{
+       pud_t *pud = fixmap_pud(addr);
+
+       BUG_ON(pud_none(*pud) || pud_bad(*pud));
+
+       return pmd_offset(pud, addr);
+}
+
+static inline pte_t * fixmap_pte(unsigned long addr)
+{
+       pmd_t *pmd = fixmap_pmd(addr);
+
+       BUG_ON(pmd_none(*pmd) || pmd_bad(*pmd));
+
+       return pte_offset_kernel(pmd, addr);
+}
+
+void __init early_fixmap_init(void)
+{
+       pgd_t *pgd;
+       pud_t *pud;
+       pmd_t *pmd;
+       unsigned long addr = FIXADDR_START;
+
+       pgd = pgd_offset_k(addr);
+       pgd_populate(&init_mm, pgd, bm_pud);
+       pud = pud_offset(pgd, addr);
+       pud_populate(&init_mm, pud, bm_pmd);
+       pmd = pmd_offset(pud, addr);
+       pmd_populate_kernel(&init_mm, pmd, bm_pte);
+
+       /*
+        * The boot-ioremap range spans multiple pmds, for which
+        * we are not preparted:
+        */
+       BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
+                    != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
+
+       if ((pmd != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)))
+            || pmd != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) {
+               WARN_ON(1);
+               pr_warn("pmd %p != %p, %p\n",
+                       pmd, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)),
+                       fixmap_pmd(fix_to_virt(FIX_BTMAP_END)));
+               pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
+                       fix_to_virt(FIX_BTMAP_BEGIN));
+               pr_warn("fix_to_virt(FIX_BTMAP_END):   %08lx\n",
+                       fix_to_virt(FIX_BTMAP_END));
+
+               pr_warn("FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
+               pr_warn("FIX_BTMAP_BEGIN:     %d\n", FIX_BTMAP_BEGIN);
+       }
+}
+
+void __set_fixmap(enum fixed_addresses idx,
+                              phys_addr_t phys, pgprot_t flags)
+{
+       unsigned long addr = __fix_to_virt(idx);
+       pte_t *pte;
+
+       if (idx >= __end_of_fixed_addresses) {
+               BUG();
+               return;
+       }
+
+       pte = fixmap_pte(addr);
+
+       if (pgprot_val(flags)) {
+               set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags));
+       } else {
+               pte_clear(&init_mm, addr, pte);
+               flush_tlb_kernel_range(addr, addr+PAGE_SIZE);
+       }
+}