x86/mm: Replace compile-time checks for 5-level paging with runtime-time checks

This patch converts the of CONFIG_X86_5LEVEL check to runtime checks for
p4d folding.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
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-mm@kvack.org
Link: http://lkml.kernel.org/r/20180214182542.69302-9-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

10 files changed, 46 insertions, 45 deletions

diff --git a/arch/x86/include/asm/pgtable_64.h b/arch/x86/include/asm/pgtable_64.h
index 81462e9a34f6..81dda8d1d0bd 100644
--- a/arch/x86/include/asm/pgtable_64.h
+++ b/arch/x86/include/asm/pgtable_64.h
@@ -217,29 +217,26 @@ static inline pgd_t pti_set_user_pgd(pgd_t *pgdp, pgd_t pgd)
 
 static inline void native_set_p4d(p4d_t *p4dp, p4d_t p4d)
 {
-#if defined(CONFIG_PAGE_TABLE_ISOLATION) && !defined(CONFIG_X86_5LEVEL)
-        p4dp->pgd = pti_set_user_pgd(&p4dp->pgd, p4d.pgd);
-#else
-        *p4dp = p4d;
-#endif
+        pgd_t pgd;
+
+        if (pgtable_l5_enabled || !IS_ENABLED(CONFIG_PAGE_TABLE_ISOLATION)) {
+                *p4dp = p4d;
+                return;
+        }
+
+        pgd = native_make_pgd(p4d_val(p4d));
+        pgd = pti_set_user_pgd((pgd_t *)p4dp, pgd);
+        *p4dp = native_make_p4d(pgd_val(pgd));
 }
 
 static inline void native_p4d_clear(p4d_t *p4d)
 {
-#ifdef CONFIG_X86_5LEVEL
         native_set_p4d(p4d, native_make_p4d(0));
-#else
-        native_set_p4d(p4d, (p4d_t) { .pgd = native_make_pgd(0)});
-#endif
 }
 
 static inline void native_set_pgd(pgd_t *pgdp, pgd_t pgd)
 {
-#ifdef CONFIG_PAGE_TABLE_ISOLATION
         *pgdp = pti_set_user_pgd(pgdp, pgd);
-#else
-        *pgdp = pgd;
-#endif
 }
 
 static inline void native_pgd_clear(pgd_t *pgd)
diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
index 9efee6f464ab..0d6d67d18ad6 100644
--- a/arch/x86/mm/dump_pagetables.c
+++ b/arch/x86/mm/dump_pagetables.c
@@ -348,9 +348,7 @@ static inline bool kasan_page_table(struct seq_file *m, struct pg_state *st,
                                 void *pt)
 {
         if (__pa(pt) == __pa(kasan_zero_pmd) ||
-#ifdef CONFIG_X86_5LEVEL
-            __pa(pt) == __pa(kasan_zero_p4d) ||
-#endif
+            (pgtable_l5_enabled && __pa(pt) == __pa(kasan_zero_p4d)) ||
             __pa(pt) == __pa(kasan_zero_pud)) {
                 pgprotval_t prot = pte_flags(kasan_zero_pte[0]);
                 note_page(m, st, __pgprot(prot), 5);
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 800de815519c..321b78060e93 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -439,7 +439,7 @@ static noinline int vmalloc_fault(unsigned long address)
         if (pgd_none(*pgd_ref))
                 return -1;
 
-        if (CONFIG_PGTABLE_LEVELS > 4) {
+        if (pgtable_l5_enabled) {
                 if (pgd_none(*pgd)) {
                         set_pgd(pgd, *pgd_ref);
                         arch_flush_lazy_mmu_mode();
@@ -454,7 +454,7 @@ static noinline int vmalloc_fault(unsigned long address)
         if (p4d_none(*p4d_ref))
                 return -1;
 
-        if (p4d_none(*p4d) && CONFIG_PGTABLE_LEVELS == 4) {
+        if (p4d_none(*p4d) && !pgtable_l5_enabled) {
                 set_p4d(p4d, *p4d_ref);
                 arch_flush_lazy_mmu_mode();
         } else {
diff --git a/arch/x86/mm/ident_map.c b/arch/x86/mm/ident_map.c
index ab33a32df2a8..9aa22be8331e 100644
--- a/arch/x86/mm/ident_map.c
+++ b/arch/x86/mm/ident_map.c
@@ -120,7 +120,7 @@ int kernel_ident_mapping_init(struct x86_mapping_info *info, pgd_t *pgd_page,
                 result = ident_p4d_init(info, p4d, addr, next);
                 if (result)
                         return result;
-                if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
+                if (pgtable_l5_enabled) {
                         set_pgd(pgd, __pgd(__pa(p4d) | info->kernpg_flag));
                 } else {
                         /*
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 6a4b20bc7527..3186e6836036 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -88,12 +88,7 @@ static int __init nonx32_setup(char *str)
 }
 __setup("noexec32=", nonx32_setup);
 
-/*
- * When memory was added make sure all the processes MM have
- * suitable PGD entries in the local PGD level page.
- */
-#ifdef CONFIG_X86_5LEVEL
-void sync_global_pgds(unsigned long start, unsigned long end)
+static void sync_global_pgds_l5(unsigned long start, unsigned long end)
 {
         unsigned long addr;
 
@@ -129,8 +124,8 @@ void sync_global_pgds(unsigned long start, unsigned long end)
                 spin_unlock(&pgd_lock);
         }
 }
-#else
-void sync_global_pgds(unsigned long start, unsigned long end)
+
+static void sync_global_pgds_l4(unsigned long start, unsigned long end)
 {
         unsigned long addr;
 
@@ -173,7 +168,18 @@ void sync_global_pgds(unsigned long start, unsigned long end)
                 spin_unlock(&pgd_lock);
         }
 }
-#endif
+
+/*
+ * When memory was added make sure all the processes MM have
+ * suitable PGD entries in the local PGD level page.
+ */
+void sync_global_pgds(unsigned long start, unsigned long end)
+{
+        if (pgtable_l5_enabled)
+                sync_global_pgds_l5(start, end);
+        else
+                sync_global_pgds_l4(start, end);
+}
 
 /*
  * NOTE: This function is marked __ref because it calls __init function
@@ -632,7 +638,7 @@ phys_p4d_init(p4d_t *p4d_page, unsigned long paddr, unsigned long paddr_end,
         unsigned long vaddr = (unsigned long)__va(paddr);
         int i = p4d_index(vaddr);
 
-        if (!IS_ENABLED(CONFIG_X86_5LEVEL))
+        if (!pgtable_l5_enabled)
                 return phys_pud_init((pud_t *) p4d_page, paddr, paddr_end, page_size_mask);
 
         for (; i < PTRS_PER_P4D; i++, paddr = paddr_next) {
@@ -712,7 +718,7 @@ kernel_physical_mapping_init(unsigned long paddr_start,
                                            page_size_mask);
 
                 spin_lock(&init_mm.page_table_lock);
-                if (IS_ENABLED(CONFIG_X86_5LEVEL))
+                if (pgtable_l5_enabled)
                         pgd_populate(&init_mm, pgd, p4d);
                 else
                         p4d_populate(&init_mm, p4d_offset(pgd, vaddr), (pud_t *) p4d);
@@ -1093,7 +1099,7 @@ remove_p4d_table(p4d_t *p4d_start, unsigned long addr, unsigned long end,
                  * 5-level case we should free them. This code will have to change
                  * to adapt for boot-time switching between 4 and 5 level page tables.
                  */
-                if (CONFIG_PGTABLE_LEVELS == 5)
+                if (pgtable_l5_enabled)
                         free_pud_table(pud_base, p4d, altmap);
         }
 
diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c
index 12ec90f62457..0df0dd13a71d 100644
--- a/arch/x86/mm/kasan_init_64.c
+++ b/arch/x86/mm/kasan_init_64.c
@@ -176,10 +176,10 @@ static void __init clear_pgds(unsigned long start,
                  * With folded p4d, pgd_clear() is nop, use p4d_clear()
                  * instead.
                  */
-                if (CONFIG_PGTABLE_LEVELS < 5)
-                        p4d_clear(p4d_offset(pgd, start));
-                else
+                if (pgtable_l5_enabled)
                         pgd_clear(pgd);
+                else
+                        p4d_clear(p4d_offset(pgd, start));
         }
 
         pgd = pgd_offset_k(start);
@@ -191,7 +191,7 @@ static inline p4d_t *early_p4d_offset(pgd_t *pgd, unsigned long addr)
 {
         unsigned long p4d;
 
-        if (!IS_ENABLED(CONFIG_X86_5LEVEL))
+        if (!pgtable_l5_enabled)
                 return (p4d_t *)pgd;
 
         p4d = __pa_nodebug(pgd_val(*pgd)) & PTE_PFN_MASK;
@@ -272,7 +272,7 @@ void __init kasan_early_init(void)
         for (i = 0; i < PTRS_PER_PUD; i++)
                 kasan_zero_pud[i] = __pud(pud_val);
 
-        for (i = 0; IS_ENABLED(CONFIG_X86_5LEVEL) && i < PTRS_PER_P4D; i++)
+        for (i = 0; pgtable_l5_enabled && i < PTRS_PER_P4D; i++)
                 kasan_zero_p4d[i] = __p4d(p4d_val);
 
         kasan_map_early_shadow(early_top_pgt);
@@ -303,7 +303,7 @@ void __init kasan_init(void)
          * bunch of things like kernel code, modules, EFI mapping, etc.
          * We need to take extra steps to not overwrite them.
          */
-        if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
+        if (pgtable_l5_enabled) {
                 void *ptr;
 
                 ptr = (void *)pgd_page_vaddr(*pgd_offset_k(KASAN_SHADOW_END));
diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
index 641169d38184..615cc03ced84 100644
--- a/arch/x86/mm/kaslr.c
+++ b/arch/x86/mm/kaslr.c
@@ -124,7 +124,7 @@ void __init kernel_randomize_memory(void)
                  */
                 entropy = remain_entropy / (ARRAY_SIZE(kaslr_regions) - i);
                 prandom_bytes_state(&rand_state, &rand, sizeof(rand));
-                if (IS_ENABLED(CONFIG_X86_5LEVEL))
+                if (pgtable_l5_enabled)
                         entropy = (rand % (entropy + 1)) & P4D_MASK;
                 else
                         entropy = (rand % (entropy + 1)) & PUD_MASK;
@@ -136,7 +136,7 @@ void __init kernel_randomize_memory(void)
                  * randomization alignment.
                  */
                 vaddr += get_padding(&kaslr_regions[i]);
-                if (IS_ENABLED(CONFIG_X86_5LEVEL))
+                if (pgtable_l5_enabled)
                         vaddr = round_up(vaddr + 1, P4D_SIZE);
                 else
                         vaddr = round_up(vaddr + 1, PUD_SIZE);
@@ -212,7 +212,7 @@ void __meminit init_trampoline(void)
                 return;
         }
 
-        if (IS_ENABLED(CONFIG_X86_5LEVEL))
+        if (pgtable_l5_enabled)
                 init_trampoline_p4d();
         else
                 init_trampoline_pud();
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 6550d37d0f06..92cb8a901c36 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -157,7 +157,7 @@ static void sync_current_stack_to_mm(struct mm_struct *mm)
         unsigned long sp = current_stack_pointer;
         pgd_t *pgd = pgd_offset(mm, sp);
 
-        if (CONFIG_PGTABLE_LEVELS > 4) {
+        if (pgtable_l5_enabled) {
                 if (unlikely(pgd_none(*pgd))) {
                         pgd_t *pgd_ref = pgd_offset_k(sp);
 
diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
index d52aaa7dc088..4845871a2006 100644
--- a/arch/x86/platform/efi/efi_64.c
+++ b/arch/x86/platform/efi/efi_64.c
@@ -227,7 +227,7 @@ int __init efi_alloc_page_tables(void)
 
         pud = pud_alloc(&init_mm, p4d, EFI_VA_END);
         if (!pud) {
-                if (CONFIG_PGTABLE_LEVELS > 4)
+                if (pgtable_l5_enabled)
                         free_page((unsigned long) pgd_page_vaddr(*pgd));
                 free_page((unsigned long)efi_pgd);
                 return -ENOMEM;
diff --git a/arch/x86/power/hibernate_64.c b/arch/x86/power/hibernate_64.c
index 0ef5e5204968..74a532989308 100644
--- a/arch/x86/power/hibernate_64.c
+++ b/arch/x86/power/hibernate_64.c
@@ -50,7 +50,7 @@ static int set_up_temporary_text_mapping(pgd_t *pgd)
 {
         pmd_t *pmd;
         pud_t *pud;
-        p4d_t *p4d;
+        p4d_t *p4d = NULL;
 
         /*
          * The new mapping only has to cover the page containing the image
@@ -66,7 +66,7 @@ static int set_up_temporary_text_mapping(pgd_t *pgd)
          * tables used by the image kernel.
          */
 
-        if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
+        if (pgtable_l5_enabled) {
                 p4d = (p4d_t *)get_safe_page(GFP_ATOMIC);
                 if (!p4d)
                         return -ENOMEM;
@@ -84,7 +84,7 @@ static int set_up_temporary_text_mapping(pgd_t *pgd)
                 __pmd((jump_address_phys & PMD_MASK) | __PAGE_KERNEL_LARGE_EXEC));
         set_pud(pud + pud_index(restore_jump_address),
                 __pud(__pa(pmd) | _KERNPG_TABLE));
-        if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
+        if (p4d) {
                 set_p4d(p4d + p4d_index(restore_jump_address), __p4d(__pa(pud) | _KERNPG_TABLE));
                 set_pgd(pgd + pgd_index(restore_jump_address), __pgd(__pa(p4d) | _KERNPG_TABLE));
         } else {