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From: Joerg Roedel <joro@8bytes.org>
To: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@kernel.org>, "H . Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Andy Lutomirski <luto@kernel.org>,
	Dave Hansen <dave.hansen@intel.com>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Juergen Gross <jgross@suse.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Borislav Petkov <bp@alien8.de>, Jiri Kosina <jkosina@suse.cz>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Brian Gerst <brgerst@gmail.com>,
	David Laight <David.Laight@aculab.com>,
	Denys Vlasenko <dvlasenk@redhat.com>,
	Eduardo Valentin <eduval@amazon.com>,
	Greg KH <gregkh@linuxfoundation.org>,
	Will Deacon <will.deacon@arm.com>,
	aliguori@amazon.com, daniel.gruss@iaik.tugraz.at,
	hughd@google.com, keescook@google.com,
	Andrea Arcangeli <aarcange@redhat.com>,
	Waiman Long <llong@redhat.com>, Pavel Machek <pavel@ucw.cz>,
	"David H . Gutteridge" <dhgutteridge@sympatico.ca>,
	jroedel@suse.de, joro@8bytes.org
Subject: [PATCH 17/39] x86/pgtable/32: Allocate 8k page-tables when PTI is enabled
Date: Wed, 11 Jul 2018 13:29:24 +0200
Message-ID: <1531308586-29340-18-git-send-email-joro@8bytes.org> (raw)
In-Reply-To: <1531308586-29340-1-git-send-email-joro@8bytes.org>

From: Joerg Roedel <jroedel@suse.de>

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@suse.de>
---
 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 abe6df1..30f9cb2 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 47b5951..db6fb77 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);
 }
-- 
2.7.4


  parent reply index

Thread overview: 81+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-11 11:29 [PATCH 00/39 v7] PTI support for x86-32 Joerg Roedel
2018-07-11 11:29 ` [PATCH 01/39] x86/asm-offsets: Move TSS_sp0 and TSS_sp1 to asm-offsets.c Joerg Roedel
2018-07-12 20:44   ` Andy Lutomirski
2018-07-11 11:29 ` [PATCH 02/39] x86/entry/32: Rename TSS_sysenter_sp0 to TSS_entry_stack Joerg Roedel
2018-07-12 20:44   ` Andy Lutomirski
2018-07-11 11:29 ` [PATCH 03/39] x86/entry/32: Load task stack from x86_tss.sp1 in SYSENTER handler Joerg Roedel
2018-07-12 20:49   ` Andy Lutomirski
2018-07-13  9:48     ` Joerg Roedel
2018-07-13 17:19       ` Andy Lutomirski
2018-07-13 23:17         ` Andy Lutomirski
2018-07-17  7:05           ` Joerg Roedel
2018-07-17 20:04             ` Andy Lutomirski
2018-07-11 11:29 ` [PATCH 04/39] x86/entry/32: Put ESPFIX code into a macro Joerg Roedel
2018-07-11 11:29 ` [PATCH 05/39] x86/entry/32: Unshare NMI return path Joerg Roedel
2018-07-12 20:53   ` Andy Lutomirski
2018-07-13 10:05     ` Joerg Roedel
2018-07-13 17:26       ` Andy Lutomirski
2018-07-11 11:29 ` [PATCH 06/39] x86/entry/32: Split off return-to-kernel path Joerg Roedel
2018-07-11 11:29 ` [PATCH 07/39] x86/entry/32: Enter the kernel via trampoline stack Joerg Roedel
2018-07-12 21:09   ` Andy Lutomirski
2018-07-13 10:56     ` Joerg Roedel
2018-07-13 17:21       ` Andy Lutomirski
2018-07-17  7:07         ` Joerg Roedel
2018-07-11 11:29 ` [PATCH 08/39] x86/entry/32: Leave " Joerg Roedel
2018-07-11 11:29 ` [PATCH 09/39] x86/entry/32: Introduce SAVE_ALL_NMI and RESTORE_ALL_NMI Joerg Roedel
2018-07-11 11:29 ` [PATCH 10/39] x86/entry/32: Handle Entry from Kernel-Mode on Entry-Stack Joerg Roedel
2018-07-13 23:31   ` Andy Lutomirski
2018-07-14  5:21     ` Joerg Roedel
2018-07-14  6:26       ` Andy Lutomirski
2018-07-14  8:01         ` Joerg Roedel
2018-07-14 14:36           ` Andy Lutomirski
2018-07-17  7:15             ` Joerg Roedel
2018-07-17 20:06               ` Andy Lutomirski
2018-07-18 11:59                 ` Joerg Roedel
2018-07-11 11:29 ` [PATCH 11/39] x86/entry/32: Simplify debug entry point Joerg Roedel
2018-07-11 11:29 ` [PATCH 12/39] x86/32: Use tss.sp1 as cpu_current_top_of_stack Joerg Roedel
2018-07-11 11:29 ` [PATCH 13/39] x86/entry/32: Add PTI cr3 switch to non-NMI entry/exit points Joerg Roedel
2018-07-11 11:29 ` [PATCH 14/39] x86/entry/32: Add PTI cr3 switches to NMI handler code Joerg Roedel
2018-07-11 11:29 ` [PATCH 15/39] x86/pgtable: Rename pti_set_user_pgd to pti_set_user_pgtbl Joerg Roedel
2018-07-11 11:29 ` [PATCH 16/39] x86/pgtable/pae: Unshare kernel PMDs when PTI is enabled Joerg Roedel
2018-07-11 11:29 ` Joerg Roedel [this message]
2018-07-11 11:29 ` [PATCH 18/39] x86/pgtable: Move pgdp kernel/user conversion functions to pgtable.h Joerg Roedel
2018-07-11 11:29 ` [PATCH 19/39] x86/pgtable: Move pti_set_user_pgtbl() " Joerg Roedel
2018-07-11 11:29 ` [PATCH 20/39] x86/pgtable: Move two more functions from pgtable_64.h " Joerg Roedel
2018-07-11 11:29 ` [PATCH 21/39] x86/mm/pae: Populate valid user PGD entries Joerg Roedel
2018-07-11 11:29 ` [PATCH 22/39] x86/mm/pae: Populate the user page-table with user pgd's Joerg Roedel
2018-07-11 11:29 ` [PATCH 23/39] x86/mm/legacy: " Joerg Roedel
2018-07-11 11:29 ` [PATCH 24/39] x86/mm/pti: Add an overflow check to pti_clone_pmds() Joerg Roedel
2018-07-11 11:29 ` [PATCH 25/39] x86/mm/pti: Define X86_CR3_PTI_PCID_USER_BIT on x86_32 Joerg Roedel
2018-07-11 11:29 ` [PATCH 26/39] x86/mm/pti: Clone CPU_ENTRY_AREA on PMD level " Joerg Roedel
2018-07-11 11:29 ` [PATCH 27/39] x86/mm/pti: Make pti_clone_kernel_text() compile on 32 bit Joerg Roedel
2018-07-11 11:29 ` [PATCH 28/39] x86/mm/pti: Keep permissions when cloning kernel text in pti_clone_kernel_text() Joerg Roedel
2018-07-13 23:25   ` Andy Lutomirski
2018-07-11 11:29 ` [PATCH 29/39] x86/mm/pti: Introduce pti_finalize() Joerg Roedel
2018-07-11 11:29 ` [PATCH 30/39] x86/mm/pti: Clone entry-text again in pti_finalize() Joerg Roedel
2018-07-13 23:21   ` Andy Lutomirski
2018-07-14  5:04     ` Joerg Roedel
2018-07-11 11:29 ` [PATCH 31/39] x86/mm/dump_pagetables: Define INIT_PGD Joerg Roedel
2018-07-11 11:29 ` [PATCH 32/39] x86/pgtable/pae: Use separate kernel PMDs for user page-table Joerg Roedel
2018-07-11 11:29 ` [PATCH 33/39] x86/ldt: Reserve address-space range on 32 bit for the LDT Joerg Roedel
2018-07-11 11:29 ` [PATCH 34/39] x86/ldt: Define LDT_END_ADDR Joerg Roedel
2018-07-13 17:29   ` Andy Lutomirski
2018-07-11 11:29 ` [PATCH 35/39] x86/ldt: Split out sanity check in map_ldt_struct() Joerg Roedel
2018-07-13 23:18   ` Andy Lutomirski
2018-07-11 11:29 ` [PATCH 36/39] x86/ldt: Enable LDT user-mapping for PAE Joerg Roedel
2018-07-11 11:29 ` [PATCH 37/39] x86/pti: Allow CONFIG_PAGE_TABLE_ISOLATION for x86_32 Joerg Roedel
2018-07-11 11:29 ` [PATCH 38/39] x86/mm/pti: Add Warning when booting on a PCID capable CPU Joerg Roedel
2018-07-13 18:59   ` Andy Lutomirski
2018-07-14  5:08     ` Joerg Roedel
2018-07-11 11:29 ` [PATCH 39/39] x86/entry/32: Add debug code to check entry/exit cr3 Joerg Roedel
2018-07-13 17:28   ` Andy Lutomirski
2018-07-14  5:09     ` Joerg Roedel
2018-07-11 16:28 ` [PATCH 00/39 v7] PTI support for x86-32 Linus Torvalds
2018-07-11 17:28   ` Jiri Kosina
2018-07-11 19:57     ` Thomas Backlund
2018-07-12 13:59       ` Boris Ostrovsky
2018-07-11 21:07   ` Pavel Machek
2018-07-16  7:51 ` Pavel Machek
2018-07-17  2:07 ` David H. Gutteridge
2018-07-17  6:16   ` Joerg Roedel
2018-07-18  9:40 [PATCH 00/39 v8] " Joerg Roedel
2018-07-18  9:40 ` [PATCH 17/39] x86/pgtable/32: Allocate 8k page-tables when PTI is enabled Joerg Roedel

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