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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 32/39] x86/pgtable/pae: Use separate kernel PMDs for user page-table
Date: Wed, 18 Jul 2018 11:41:09 +0200	[thread overview]
Message-ID: <1531906876-13451-33-git-send-email-joro@8bytes.org> (raw)
In-Reply-To: <1531906876-13451-1-git-send-email-joro@8bytes.org>

From: Joerg Roedel <jroedel@suse.de>

We need separate kernel PMDs in the user page-table when PTI
is enabled to map the per-process LDT for user-space.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
 arch/x86/mm/pgtable.c | 100 ++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 81 insertions(+), 19 deletions(-)

diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index db6fb77..8e4e63d 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -182,6 +182,14 @@ static void pgd_dtor(pgd_t *pgd)
  */
 #define PREALLOCATED_PMDS	UNSHARED_PTRS_PER_PGD
 
+/*
+ * We allocate separate PMDs for the kernel part of the user page-table
+ * when PTI is enabled. We need them to map the per-process LDT into the
+ * user-space page-table.
+ */
+#define PREALLOCATED_USER_PMDS	 (static_cpu_has(X86_FEATURE_PTI) ? \
+					KERNEL_PGD_PTRS : 0)
+
 void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd)
 {
 	paravirt_alloc_pmd(mm, __pa(pmd) >> PAGE_SHIFT);
@@ -202,14 +210,14 @@ void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd)
 
 /* No need to prepopulate any pagetable entries in non-PAE modes. */
 #define PREALLOCATED_PMDS	0
-
+#define PREALLOCATED_USER_PMDS	 0
 #endif	/* CONFIG_X86_PAE */
 
-static void free_pmds(struct mm_struct *mm, pmd_t *pmds[])
+static void free_pmds(struct mm_struct *mm, pmd_t *pmds[], int count)
 {
 	int i;
 
-	for(i = 0; i < PREALLOCATED_PMDS; i++)
+	for (i = 0; i < count; i++)
 		if (pmds[i]) {
 			pgtable_pmd_page_dtor(virt_to_page(pmds[i]));
 			free_page((unsigned long)pmds[i]);
@@ -217,7 +225,7 @@ static void free_pmds(struct mm_struct *mm, pmd_t *pmds[])
 		}
 }
 
-static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[])
+static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[], int count)
 {
 	int i;
 	bool failed = false;
@@ -226,7 +234,7 @@ static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[])
 	if (mm == &init_mm)
 		gfp &= ~__GFP_ACCOUNT;
 
-	for(i = 0; i < PREALLOCATED_PMDS; i++) {
+	for (i = 0; i < count; i++) {
 		pmd_t *pmd = (pmd_t *)__get_free_page(gfp);
 		if (!pmd)
 			failed = true;
@@ -241,7 +249,7 @@ static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[])
 	}
 
 	if (failed) {
-		free_pmds(mm, pmds);
+		free_pmds(mm, pmds, count);
 		return -ENOMEM;
 	}
 
@@ -254,23 +262,38 @@ static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[])
  * preallocate which never got a corresponding vma will need to be
  * freed manually.
  */
+static void mop_up_one_pmd(struct mm_struct *mm, pgd_t *pgdp)
+{
+	pgd_t pgd = *pgdp;
+
+	if (pgd_val(pgd) != 0) {
+		pmd_t *pmd = (pmd_t *)pgd_page_vaddr(pgd);
+
+		*pgdp = native_make_pgd(0);
+
+		paravirt_release_pmd(pgd_val(pgd) >> PAGE_SHIFT);
+		pmd_free(mm, pmd);
+		mm_dec_nr_pmds(mm);
+	}
+}
+
 static void pgd_mop_up_pmds(struct mm_struct *mm, pgd_t *pgdp)
 {
 	int i;
 
-	for(i = 0; i < PREALLOCATED_PMDS; i++) {
-		pgd_t pgd = pgdp[i];
+	for (i = 0; i < PREALLOCATED_PMDS; i++)
+		mop_up_one_pmd(mm, &pgdp[i]);
 
-		if (pgd_val(pgd) != 0) {
-			pmd_t *pmd = (pmd_t *)pgd_page_vaddr(pgd);
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
 
-			pgdp[i] = native_make_pgd(0);
+	if (!static_cpu_has(X86_FEATURE_PTI))
+		return;
 
-			paravirt_release_pmd(pgd_val(pgd) >> PAGE_SHIFT);
-			pmd_free(mm, pmd);
-			mm_dec_nr_pmds(mm);
-		}
-	}
+	pgdp = kernel_to_user_pgdp(pgdp);
+
+	for (i = 0; i < PREALLOCATED_USER_PMDS; i++)
+		mop_up_one_pmd(mm, &pgdp[i + KERNEL_PGD_BOUNDARY]);
+#endif
 }
 
 static void pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmds[])
@@ -296,6 +319,38 @@ static void pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd, pmd_t *pmds[])
 	}
 }
 
+#ifdef CONFIG_PAGE_TABLE_ISOLATION
+static void pgd_prepopulate_user_pmd(struct mm_struct *mm,
+				     pgd_t *k_pgd, pmd_t *pmds[])
+{
+	pgd_t *s_pgd = kernel_to_user_pgdp(swapper_pg_dir);
+	pgd_t *u_pgd = kernel_to_user_pgdp(k_pgd);
+	p4d_t *u_p4d;
+	pud_t *u_pud;
+	int i;
+
+	u_p4d = p4d_offset(u_pgd, 0);
+	u_pud = pud_offset(u_p4d, 0);
+
+	s_pgd += KERNEL_PGD_BOUNDARY;
+	u_pud += KERNEL_PGD_BOUNDARY;
+
+	for (i = 0; i < PREALLOCATED_USER_PMDS; i++, u_pud++, s_pgd++) {
+		pmd_t *pmd = pmds[i];
+
+		memcpy(pmd, (pmd_t *)pgd_page_vaddr(*s_pgd),
+		       sizeof(pmd_t) * PTRS_PER_PMD);
+
+		pud_populate(mm, u_pud, pmd);
+	}
+
+}
+#else
+static void pgd_prepopulate_user_pmd(struct mm_struct *mm,
+				     pgd_t *k_pgd, pmd_t *pmds[])
+{
+}
+#endif
 /*
  * Xen paravirt assumes pgd table should be in one page. 64 bit kernel also
  * assumes that pgd should be in one page.
@@ -376,6 +431,7 @@ static inline void _pgd_free(pgd_t *pgd)
 pgd_t *pgd_alloc(struct mm_struct *mm)
 {
 	pgd_t *pgd;
+	pmd_t *u_pmds[PREALLOCATED_USER_PMDS];
 	pmd_t *pmds[PREALLOCATED_PMDS];
 
 	pgd = _pgd_alloc();
@@ -385,12 +441,15 @@ pgd_t *pgd_alloc(struct mm_struct *mm)
 
 	mm->pgd = pgd;
 
-	if (preallocate_pmds(mm, pmds) != 0)
+	if (preallocate_pmds(mm, pmds, PREALLOCATED_PMDS) != 0)
 		goto out_free_pgd;
 
-	if (paravirt_pgd_alloc(mm) != 0)
+	if (preallocate_pmds(mm, u_pmds, PREALLOCATED_USER_PMDS) != 0)
 		goto out_free_pmds;
 
+	if (paravirt_pgd_alloc(mm) != 0)
+		goto out_free_user_pmds;
+
 	/*
 	 * Make sure that pre-populating the pmds is atomic with
 	 * respect to anything walking the pgd_list, so that they
@@ -400,13 +459,16 @@ pgd_t *pgd_alloc(struct mm_struct *mm)
 
 	pgd_ctor(mm, pgd);
 	pgd_prepopulate_pmd(mm, pgd, pmds);
+	pgd_prepopulate_user_pmd(mm, pgd, u_pmds);
 
 	spin_unlock(&pgd_lock);
 
 	return pgd;
 
+out_free_user_pmds:
+	free_pmds(mm, u_pmds, PREALLOCATED_USER_PMDS);
 out_free_pmds:
-	free_pmds(mm, pmds);
+	free_pmds(mm, pmds, PREALLOCATED_PMDS);
 out_free_pgd:
 	_pgd_free(pgd);
 out:
-- 
2.7.4


  parent reply	other threads:[~2018-07-18  9:41 UTC|newest]

Thread overview: 97+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-18  9:40 [PATCH 00/39 v8] PTI support for x86-32 Joerg Roedel
2018-07-18  9:40 ` [PATCH 01/39] x86/asm-offsets: Move TSS_sp0 and TSS_sp1 to asm-offsets.c Joerg Roedel
2018-07-19 23:18   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:40 ` [PATCH 02/39] x86/entry/32: Rename TSS_sysenter_sp0 to TSS_entry2task_stack Joerg Roedel
2018-07-19 23:19   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:40 ` [PATCH 03/39] x86/entry/32: Load task stack from x86_tss.sp1 in SYSENTER handler Joerg Roedel
2018-07-19 23:19   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:40 ` [PATCH 04/39] x86/entry/32: Put ESPFIX code into a macro Joerg Roedel
2018-07-19 23:20   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:40 ` [PATCH 05/39] x86/entry/32: Unshare NMI return path Joerg Roedel
2018-07-19 23:21   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:40 ` [PATCH 06/39] x86/entry/32: Split off return-to-kernel path Joerg Roedel
2018-07-19 23:21   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:40 ` [PATCH 07/39] x86/entry/32: Enter the kernel via trampoline stack Joerg Roedel
2018-07-18 18:09   ` Brian Gerst
2018-07-19 20:52     ` Thomas Gleixner
2018-07-19 23:22   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:40 ` [PATCH 08/39] x86/entry/32: Leave " Joerg Roedel
2018-07-19 23:22   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:40 ` [PATCH 09/39] x86/entry/32: Introduce SAVE_ALL_NMI and RESTORE_ALL_NMI Joerg Roedel
2018-07-19 23:23   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:40 ` [PATCH 10/39] x86/entry/32: Handle Entry from Kernel-Mode on Entry-Stack Joerg Roedel
2018-07-19 23:23   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-10-12 18:29   ` [PATCH 10/39] " Jan Kiszka
2018-10-13  9:54     ` [PATCH] x86/entry/32: Fix setup of CS high bits Jan Kiszka
2018-10-13 15:12       ` Andy Lutomirski
2018-10-15 13:08         ` Jan Kiszka
2018-10-15 13:14           ` David Laight
2018-10-15 13:18             ` Jan Kiszka
2018-10-15 13:29               ` David Laight
2018-10-15  9:10       ` Joerg Roedel
2018-10-15 14:09       ` [PATCH v2] " Jan Kiszka
2018-10-15 15:09         ` [tip:x86/urgent] x86/entry/32: Clear the " tip-bot for Jan Kiszka
2018-10-18  6:21         ` tip-bot for Jan Kiszka
2018-07-18  9:40 ` [PATCH 11/39] x86/entry/32: Simplify debug entry point Joerg Roedel
2018-07-19 23:24   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:40 ` [PATCH 12/39] x86/entry/32: Add PTI cr3 switch to non-NMI entry/exit points Joerg Roedel
2018-07-19 23:24   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:40 ` [PATCH 13/39] x86/entry/32: Add PTI cr3 switches to NMI handler code Joerg Roedel
2018-07-19 23:25   ` [tip:x86/pti] x86/entry/32: Add PTI CR3 " tip-bot for Joerg Roedel
2018-07-18  9:40 ` [PATCH 14/39] x86/entry: Rename update_sp0 to update_task_stack Joerg Roedel
2018-07-19 23:25   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:40 ` [PATCH 15/39] x86/pgtable: Rename pti_set_user_pgd to pti_set_user_pgtbl Joerg Roedel
2018-07-19 23:26   ` [tip:x86/pti] x86/pgtable: Rename pti_set_user_pgd() to pti_set_user_pgtbl() tip-bot for Joerg Roedel
2018-07-18  9:40 ` [PATCH 16/39] x86/pgtable/pae: Unshare kernel PMDs when PTI is enabled Joerg Roedel
2018-07-19 23:26   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:40 ` [PATCH 17/39] x86/pgtable/32: Allocate 8k page-tables " Joerg Roedel
2018-07-19 23:27   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:40 ` [PATCH 18/39] x86/pgtable: Move pgdp kernel/user conversion functions to pgtable.h Joerg Roedel
2018-07-19 23:27   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:40 ` [PATCH 19/39] x86/pgtable: Move pti_set_user_pgtbl() " Joerg Roedel
2018-07-19 23:28   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:40 ` [PATCH 20/39] x86/pgtable: Move two more functions from pgtable_64.h " Joerg Roedel
2018-07-19 23:28   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:40 ` [PATCH 21/39] x86/mm/pae: Populate valid user PGD entries Joerg Roedel
2018-07-19 23:29   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:40 ` [PATCH 22/39] x86/mm/pae: Populate the user page-table with user pgd's Joerg Roedel
2018-07-19 23:30   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:41 ` [PATCH 23/39] x86/mm/legacy: " Joerg Roedel
2018-07-19 23:30   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:41 ` [PATCH 24/39] x86/mm/pti: Add an overflow check to pti_clone_pmds() Joerg Roedel
2018-07-19 23:31   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:41 ` [PATCH 25/39] x86/mm/pti: Define X86_CR3_PTI_PCID_USER_BIT on x86_32 Joerg Roedel
2018-07-19 23:31   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:41 ` [PATCH 26/39] x86/mm/pti: Clone CPU_ENTRY_AREA on PMD level " Joerg Roedel
2018-07-19 23:32   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:41 ` [PATCH 27/39] x86/mm/pti: Make pti_clone_kernel_text() compile on 32 bit Joerg Roedel
2018-07-19 23:32   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:41 ` [PATCH 28/39] x86/mm/pti: Keep permissions when cloning kernel text in pti_clone_kernel_text() Joerg Roedel
2018-07-19 23:33   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:41 ` [PATCH 29/39] x86/mm/pti: Introduce pti_finalize() Joerg Roedel
2018-07-19 23:33   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:41 ` [PATCH 30/39] x86/mm/pti: Clone entry-text again in pti_finalize() Joerg Roedel
2018-07-19 23:34   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:41 ` [PATCH 31/39] x86/mm/dump_pagetables: Define INIT_PGD Joerg Roedel
2018-07-19 23:34   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:41 ` Joerg Roedel [this message]
2018-07-19 23:35   ` [tip:x86/pti] x86/pgtable/pae: Use separate kernel PMDs for user page-table tip-bot for Joerg Roedel
2018-10-05 14:06   ` [PATCH 32/39] " Arnd Bergmann
2018-07-18  9:41 ` [PATCH 33/39] x86/ldt: Reserve address-space range on 32 bit for the LDT Joerg Roedel
2018-07-19 23:35   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:41 ` [PATCH 34/39] x86/ldt: Define LDT_END_ADDR Joerg Roedel
2018-07-19 23:36   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:41 ` [PATCH 35/39] x86/ldt: Split out sanity check in map_ldt_struct() Joerg Roedel
2018-07-19 23:36   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:41 ` [PATCH 36/39] x86/ldt: Enable LDT user-mapping for PAE Joerg Roedel
2018-07-19 23:37   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:41 ` [PATCH 37/39] x86/pti: Allow CONFIG_PAGE_TABLE_ISOLATION for x86_32 Joerg Roedel
2018-07-19 23:37   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:41 ` [PATCH 38/39] x86/mm/pti: Add Warning when booting on a PCID capable CPU Joerg Roedel
2018-07-19 23:38   ` [tip:x86/pti] " tip-bot for Joerg Roedel
2018-07-18  9:41 ` [PATCH 39/39] x86/entry/32: Add debug code to check entry/exit cr3 Joerg Roedel
2018-07-19 23:38   ` [tip:x86/pti] x86/entry/32: Add debug code to check entry/exit CR3 tip-bot for Joerg Roedel
2018-07-18 11:59 ` [PATCH 00/39 v8] PTI support for x86-32 Pavel Machek
2018-07-19 23:21 ` Thomas Gleixner
2018-07-20  7:59   ` Joerg Roedel
  -- strict thread matches above, loose matches on Subject: below --
2018-07-11 11:29 [PATCH 00/39 v7] " Joerg Roedel
2018-07-11 11:29 ` [PATCH 32/39] x86/pgtable/pae: Use separate kernel PMDs for user page-table Joerg Roedel

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