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authorLinus Torvalds <torvalds@linux-foundation.org>2017-03-10 19:59:07 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2017-03-10 19:59:07 +0300
commitbaeedc7158da5b0f489d04125ba6adfba532a6f7 (patch)
tree1f42b5cd4a961ed10673578a28602dd13d09ab99 /mm/kasan
parent8fe3ccaed080a7804bc459c42e0419253973be92 (diff)
parent90eceff1a375f6ffa78caf8654e787c0a8a591ef (diff)
downloadlinux-baeedc7158da5b0f489d04125ba6adfba532a6f7.tar.xz
Merge branch 'prep-for-5level'
Merge 5-level page table prep from Kirill Shutemov: "Here's relatively low-risk part of 5-level paging patchset. Merging it now will make x86 5-level paging enabling in v4.12 easier. The first patch is actually x86-specific: detect 5-level paging support. It boils down to single define. The rest of patchset converts Linux MMU abstraction from 4- to 5-level paging. Enabling of new abstraction in most cases requires adding single line of code in arch-specific code. The rest is taken care by asm-generic/. Changes to mm/ code are mostly mechanical: add support for new page table level -- p4d_t -- where we deal with pud_t now. v2: - fix build on microblaze (Michal); - comment for __ARCH_HAS_5LEVEL_HACK in kasan_populate_zero_shadow(); - acks from Michal" * emailed patches from Kirill A Shutemov <kirill.shutemov@linux.intel.com>: mm: introduce __p4d_alloc() mm: convert generic code to 5-level paging asm-generic: introduce <asm-generic/pgtable-nop4d.h> arch, mm: convert all architectures to use 5level-fixup.h asm-generic: introduce __ARCH_USE_5LEVEL_HACK asm-generic: introduce 5level-fixup.h x86/cpufeature: Add 5-level paging detection
Diffstat (limited to 'mm/kasan')
-rw-r--r--mm/kasan/kasan_init.c44
1 files changed, 39 insertions, 5 deletions
diff --git a/mm/kasan/kasan_init.c b/mm/kasan/kasan_init.c
index 31238dad85fb..b96a5f773d88 100644
--- a/mm/kasan/kasan_init.c
+++ b/mm/kasan/kasan_init.c
@@ -30,6 +30,9 @@
*/
unsigned char kasan_zero_page[PAGE_SIZE] __page_aligned_bss;
+#if CONFIG_PGTABLE_LEVELS > 4
+p4d_t kasan_zero_p4d[PTRS_PER_P4D] __page_aligned_bss;
+#endif
#if CONFIG_PGTABLE_LEVELS > 3
pud_t kasan_zero_pud[PTRS_PER_PUD] __page_aligned_bss;
#endif
@@ -82,10 +85,10 @@ static void __init zero_pmd_populate(pud_t *pud, unsigned long addr,
} while (pmd++, addr = next, addr != end);
}
-static void __init zero_pud_populate(pgd_t *pgd, unsigned long addr,
+static void __init zero_pud_populate(p4d_t *p4d, unsigned long addr,
unsigned long end)
{
- pud_t *pud = pud_offset(pgd, addr);
+ pud_t *pud = pud_offset(p4d, addr);
unsigned long next;
do {
@@ -107,6 +110,23 @@ static void __init zero_pud_populate(pgd_t *pgd, unsigned long addr,
} while (pud++, addr = next, addr != end);
}
+static void __init zero_p4d_populate(pgd_t *pgd, unsigned long addr,
+ unsigned long end)
+{
+ p4d_t *p4d = p4d_offset(pgd, addr);
+ unsigned long next;
+
+ do {
+ next = p4d_addr_end(addr, end);
+
+ if (p4d_none(*p4d)) {
+ p4d_populate(&init_mm, p4d,
+ early_alloc(PAGE_SIZE, NUMA_NO_NODE));
+ }
+ zero_pud_populate(p4d, addr, next);
+ } while (p4d++, addr = next, addr != end);
+}
+
/**
* kasan_populate_zero_shadow - populate shadow memory region with
* kasan_zero_page
@@ -125,6 +145,7 @@ void __init kasan_populate_zero_shadow(const void *shadow_start,
next = pgd_addr_end(addr, end);
if (IS_ALIGNED(addr, PGDIR_SIZE) && end - addr >= PGDIR_SIZE) {
+ p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
@@ -135,9 +156,22 @@ void __init kasan_populate_zero_shadow(const void *shadow_start,
* 3,2 - level page tables where we don't have
* puds,pmds, so pgd_populate(), pud_populate()
* is noops.
+ *
+ * The ifndef is required to avoid build breakage.
+ *
+ * With 5level-fixup.h, pgd_populate() is not nop and
+ * we reference kasan_zero_p4d. It's not defined
+ * unless 5-level paging enabled.
+ *
+ * The ifndef can be dropped once all KASAN-enabled
+ * architectures will switch to pgtable-nop4d.h.
*/
- pgd_populate(&init_mm, pgd, lm_alias(kasan_zero_pud));
- pud = pud_offset(pgd, addr);
+#ifndef __ARCH_HAS_5LEVEL_HACK
+ pgd_populate(&init_mm, pgd, lm_alias(kasan_zero_p4d));
+#endif
+ p4d = p4d_offset(pgd, addr);
+ p4d_populate(&init_mm, p4d, lm_alias(kasan_zero_pud));
+ pud = pud_offset(p4d, addr);
pud_populate(&init_mm, pud, lm_alias(kasan_zero_pmd));
pmd = pmd_offset(pud, addr);
pmd_populate_kernel(&init_mm, pmd, lm_alias(kasan_zero_pte));
@@ -148,6 +182,6 @@ void __init kasan_populate_zero_shadow(const void *shadow_start,
pgd_populate(&init_mm, pgd,
early_alloc(PAGE_SIZE, NUMA_NO_NODE));
}
- zero_pud_populate(pgd, addr, next);
+ zero_p4d_populate(pgd, addr, next);
} while (pgd++, addr = next, addr != end);
}