x86/mm: Make kernel_physical_mapping_init() support 5-level paging

Populate additional page table level if CONFIG_X86_5LEVEL is enabled.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170606113133.22974-12-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 60 insertions, 9 deletions

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 7a9497ac468d..b863d14e452a 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -624,6 +624,57 @@ phys_pud_init(pud_t *pud_page, unsigned long paddr, unsigned long paddr_end,
         return paddr_last;
 }
 
+static unsigned long __meminit
+phys_p4d_init(p4d_t *p4d_page, unsigned long paddr, unsigned long paddr_end,
+              unsigned long page_size_mask)
+{
+        unsigned long paddr_next, paddr_last = paddr_end;
+        unsigned long vaddr = (unsigned long)__va(paddr);
+        int i = p4d_index(vaddr);
+
+        if (!IS_ENABLED(CONFIG_X86_5LEVEL))
+                return phys_pud_init((pud_t *) p4d_page, paddr, paddr_end, page_size_mask);
+
+        for (; i < PTRS_PER_P4D; i++, paddr = paddr_next) {
+                p4d_t *p4d;
+                pud_t *pud;
+
+                vaddr = (unsigned long)__va(paddr);
+                p4d = p4d_page + p4d_index(vaddr);
+                paddr_next = (paddr & P4D_MASK) + P4D_SIZE;
+
+                if (paddr >= paddr_end) {
+                        if (!after_bootmem &&
+                            !e820__mapped_any(paddr & P4D_MASK, paddr_next,
+                                             E820_TYPE_RAM) &&
+                            !e820__mapped_any(paddr & P4D_MASK, paddr_next,
+                                             E820_TYPE_RESERVED_KERN))
+                                set_p4d(p4d, __p4d(0));
+                        continue;
+                }
+
+                if (!p4d_none(*p4d)) {
+                        pud = pud_offset(p4d, 0);
+                        paddr_last = phys_pud_init(pud, paddr,
+                                        paddr_end,
+                                        page_size_mask);
+                        __flush_tlb_all();
+                        continue;
+                }
+
+                pud = alloc_low_page();
+                paddr_last = phys_pud_init(pud, paddr, paddr_end,
+                                           page_size_mask);
+
+                spin_lock(&init_mm.page_table_lock);
+                p4d_populate(&init_mm, p4d, pud);
+                spin_unlock(&init_mm.page_table_lock);
+        }
+        __flush_tlb_all();
+
+        return paddr_last;
+}
+
 /*
  * Create page table mapping for the physical memory for specific physical
  * addresses. The virtual and physical addresses have to be aligned on PMD level
@@ -645,26 +696,26 @@ kernel_physical_mapping_init(unsigned long paddr_start,
         for (; vaddr < vaddr_end; vaddr = vaddr_next) {
                 pgd_t *pgd = pgd_offset_k(vaddr);
                 p4d_t *p4d;
-                pud_t *pud;
 
                 vaddr_next = (vaddr & PGDIR_MASK) + PGDIR_SIZE;
 
-                BUILD_BUG_ON(pgd_none(*pgd));
-                p4d = p4d_offset(pgd, vaddr);
-                if (p4d_val(*p4d)) {
-                        pud = (pud_t *)p4d_page_vaddr(*p4d);
-                        paddr_last = phys_pud_init(pud, __pa(vaddr),
+                if (pgd_val(*pgd)) {
+                        p4d = (p4d_t *)pgd_page_vaddr(*pgd);
+                        paddr_last = phys_p4d_init(p4d, __pa(vaddr),
                                                    __pa(vaddr_end),
                                                    page_size_mask);
                         continue;
                 }
 
-                pud = alloc_low_page();
-                paddr_last = phys_pud_init(pud, __pa(vaddr), __pa(vaddr_end),
+                p4d = alloc_low_page();
+                paddr_last = phys_p4d_init(p4d, __pa(vaddr), __pa(vaddr_end),
                                            page_size_mask);
 
                 spin_lock(&init_mm.page_table_lock);
-                p4d_populate(&init_mm, p4d, pud);
+                if (IS_ENABLED(CONFIG_X86_5LEVEL))
+                        pgd_populate(&init_mm, pgd, p4d);
+                else
+                        p4d_populate(&init_mm, p4d_offset(pgd, vaddr), (pud_t *) p4d);
                 spin_unlock(&init_mm.page_table_lock);
                 pgd_changed = true;
         }