Commit-ID: e3238faf20fb1b51a814497751398ab525a2c884
Gitweb: https://git.kernel.org/tip/e3238faf20fb1b51a814497751398ab525a2c884
Author: Joerg Roedel <jroedel@xxxxxxx>
AuthorDate: Wed, 18 Jul 2018 11:40:54 +0200
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Fri, 20 Jul 2018 01:11:41 +0200
x86/pgtable/32: Allocate 8k page-tables when PTI is enabled
Allocate a kernel and a user page-table root when PTI is enabled. Also
allocate a full page per root for PAE because otherwise the bit to flip in
CR3 to switch between them would be non-constant, which creates a lot of
hassle. Keep that for a later optimization.
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Tested-by: Pavel Machek <pavel@xxxxxx>
Cc: "H . Peter Anvin" <hpa@xxxxxxxxx>
Cc: linux-mm@xxxxxxxxx
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Jiri Kosina <jkosina@xxxxxxx>
Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: David Laight <David.Laight@xxxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: Eduardo Valentin <eduval@xxxxxxxxxx>
Cc: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: aliguori@xxxxxxxxxx
Cc: daniel.gruss@xxxxxxxxxxxxxx
Cc: hughd@xxxxxxxxxx
Cc: keescook@xxxxxxxxxx
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Waiman Long <llong@xxxxxxxxxx>
Cc: "David H . Gutteridge" <dhgutteridge@xxxxxxxxxxxx>
Cc: joro@xxxxxxxxxx
Link: https://lkml.kernel.org/r/1531906876-13451-18-git-send-email-joro@xxxxxxxxxx
---
arch/x86/kernel/head_32.S | 20 +++++++++++++++-----
arch/x86/mm/pgtable.c | 5 +++--
2 files changed, 18 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index abe6df15a8fb..30f9cb2c0b55 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -512,11 +512,18 @@ ENTRY(initial_code)
ENTRY(setup_once_ref)
.long setup_once
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
+#define PGD_ALIGN (2 * PAGE_SIZE)
+#define PTI_USER_PGD_FILL 1024
+#else
+#define PGD_ALIGN (PAGE_SIZE)
+#define PTI_USER_PGD_FILL 0
+#endif
/*
* BSS section
*/
__PAGE_ALIGNED_BSS
- .align PAGE_SIZE
+ .align PGD_ALIGN
#ifdef CONFIG_X86_PAE
.globl initial_pg_pmd
initial_pg_pmd:
@@ -526,14 +533,17 @@ initial_pg_pmd:
initial_page_table:
.fill 1024,4,0
#endif
+ .align PGD_ALIGN
initial_pg_fixmap:
.fill 1024,4,0
-.globl empty_zero_page
-empty_zero_page:
- .fill 4096,1,0
.globl swapper_pg_dir
+ .align PGD_ALIGN
swapper_pg_dir:
.fill 1024,4,0
+ .fill PTI_USER_PGD_FILL,4,0
+.globl empty_zero_page
+empty_zero_page:
+ .fill 4096,1,0
EXPORT_SYMBOL(empty_zero_page)
/*
@@ -542,7 +552,7 @@ EXPORT_SYMBOL(empty_zero_page)
#ifdef CONFIG_X86_PAE
__PAGE_ALIGNED_DATA
/* Page-aligned for the benefit of paravirt? */
- .align PAGE_SIZE
+ .align PGD_ALIGN
ENTRY(initial_page_table)
.long pa(initial_pg_pmd+PGD_IDENT_ATTR),0 /* low identity map */
# if KPMDS == 3
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 47b5951e592b..db6fb7740bf7 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -343,7 +343,8 @@ static inline pgd_t *_pgd_alloc(void)
* We allocate one page for pgd.
*/
if (!SHARED_KERNEL_PMD)
- return (pgd_t *)__get_free_page(PGALLOC_GFP);
+ return (pgd_t *)__get_free_pages(PGALLOC_GFP,
+ PGD_ALLOCATION_ORDER);
/*
* Now PAE kernel is not running as a Xen domain. We can allocate
@@ -355,7 +356,7 @@ static inline pgd_t *_pgd_alloc(void)
static inline void _pgd_free(pgd_t *pgd)
{
if (!SHARED_KERNEL_PMD)
- free_page((unsigned long)pgd);
+ free_pages((unsigned long)pgd, PGD_ALLOCATION_ORDER);
else
kmem_cache_free(pgd_cache, pgd);
}
--
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