Commit-ID:  91f606a8fa68264224cbc76888fa8649cdbe9990
Gitweb:     https://git.kernel.org/tip/91f606a8fa68264224cbc76888fa8649cdbe9990
Author:     Kirill A. Shutemov <kirill.shute...@linux.intel.com>
AuthorDate: Wed, 14 Feb 2018 21:25:41 +0300
Committer:  Ingo Molnar <mi...@kernel.org>
CommitDate: Fri, 16 Feb 2018 10:48:49 +0100

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.shute...@linux.intel.com>
Cc: Andy Lutomirski <l...@kernel.org>
Cc: Arjan van de Ven <ar...@linux.intel.com>
Cc: Borislav Petkov <b...@suse.de>
Cc: Dan Williams <dan.j.willi...@intel.com>
Cc: Dave Hansen <dave.han...@linux.intel.com>
Cc: David Woodhouse <dw...@infradead.org>
Cc: Josh Poimboeuf <jpoim...@redhat.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: linux...@kvack.org
Link: 
http://lkml.kernel.org/r/20180214182542.69302-9-kirill.shute...@linux.intel.com
Signed-off-by: Ingo Molnar <mi...@kernel.org>
---
 arch/x86/include/asm/pgtable_64.h | 23 ++++++++++-------------
 arch/x86/mm/dump_pagetables.c     |  4 +---
 arch/x86/mm/fault.c               |  4 ++--
 arch/x86/mm/ident_map.c           |  2 +-
 arch/x86/mm/init_64.c             | 30 ++++++++++++++++++------------
 arch/x86/mm/kasan_init_64.c       | 12 ++++++------
 arch/x86/mm/kaslr.c               |  6 +++---
 arch/x86/mm/tlb.c                 |  2 +-
 arch/x86/platform/efi/efi_64.c    |  2 +-
 arch/x86/power/hibernate_64.c     |  6 +++---
 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 81462e9..81dda8d 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 9efee6f..0d6d67d 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 800de81..321b780 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 ab33a32..9aa22be 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 6a4b20b..3186e68 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 12ec90f..0df0dd1 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 641169d..615cc03 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 6550d37..92cb8a9 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 d52aaa7..4845871 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 0ef5e520..74a5329 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 {

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