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From: Rick Edgecombe <rick.p.edgecombe@intel.com>
To: dave.hansen@intel.com, luto@kernel.org, peterz@infradead.org,
	x86@kernel.org, akpm@linux-foundation.org, keescook@chromium.org,
	shakeelb@google.com, vbabka@suse.cz, rppt@kernel.org
Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>,
	linux-mm@kvack.org, linux-hardening@vger.kernel.org,
	kernel-hardening@lists.openwall.com, ira.weiny@intel.com,
	dan.j.williams@intel.com, linux-kernel@vger.kernel.org
Subject: [RFC PATCH v2 13/19] mm/debug_vm_page_table: Use setters instead of WRITE_ONCE
Date: Mon, 30 Aug 2021 16:59:21 -0700	[thread overview]
Message-ID: <20210830235927.6443-14-rick.p.edgecombe@intel.com> (raw)
In-Reply-To: <20210830235927.6443-1-rick.p.edgecombe@intel.com>

Currently debug_vm_page_table uses some raw WRITE_ONCE invocations to
write to page tables, which PKS tables is designed to prevent. So use the
set_p**() helpers instead of WRITE_ONCE for x86, so debug_vm_page_table
will work with PKS tables enabled.

Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
 mm/debug_vm_pgtable.c | 36 +++++++++++++++++++++++++++++++++---
 1 file changed, 33 insertions(+), 3 deletions(-)

diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index 1c922691aa61..a0b8859ecf04 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -411,11 +411,17 @@ static void __init pmd_huge_tests(pmd_t *pmdp, unsigned long pfn, pgprot_t prot)
 		return;
 
 	pr_debug("Validating PMD huge\n");
+
+#ifdef CONFIG_X86
+	/* Use setter so that protections can be toggled if needed */
+	set_pmd(pmdp, __pmd(0));
+#else
+	WRITE_ONCE(*pmdp, __pmd(0));
+#endif
 	/*
 	 * X86 defined pmd_set_huge() verifies that the given
 	 * PMD is not a populated non-leaf entry.
 	 */
-	WRITE_ONCE(*pmdp, __pmd(0));
 	WARN_ON(!pmd_set_huge(pmdp, __pfn_to_phys(pfn), prot));
 	WARN_ON(!pmd_clear_huge(pmdp));
 	pmd = READ_ONCE(*pmdp);
@@ -430,11 +436,16 @@ static void __init pud_huge_tests(pud_t *pudp, unsigned long pfn, pgprot_t prot)
 		return;
 
 	pr_debug("Validating PUD huge\n");
+#ifdef CONFIG_X86
+	/* Use setter so that protections can be toggled if needed */
+	set_pud(pudp, __pud(0));
+#else
+	WRITE_ONCE(*pudp, __pud(0));
+#endif
 	/*
 	 * X86 defined pud_set_huge() verifies that the given
 	 * PUD is not a populated non-leaf entry.
 	 */
-	WRITE_ONCE(*pudp, __pud(0));
 	WARN_ON(!pud_set_huge(pudp, __pfn_to_phys(pfn), prot));
 	WARN_ON(!pud_clear_huge(pudp));
 	pud = READ_ONCE(*pudp);
@@ -473,7 +484,12 @@ static void __init pud_clear_tests(struct mm_struct *mm, pud_t *pudp)
 
 	pr_debug("Validating PUD clear\n");
 	pud = __pud(pud_val(pud) | RANDOM_ORVALUE);
+#ifdef CONFIG_X86
+	/* Use setter so that protections can be toggled if needed */
+	set_pud(pudp, pud);
+#else
 	WRITE_ONCE(*pudp, pud);
+#endif
 	pud_clear(pudp);
 	pud = READ_ONCE(*pudp);
 	WARN_ON(!pud_none(pud));
@@ -514,7 +530,12 @@ static void __init p4d_clear_tests(struct mm_struct *mm, p4d_t *p4dp)
 
 	pr_debug("Validating P4D clear\n");
 	p4d = __p4d(p4d_val(p4d) | RANDOM_ORVALUE);
+#ifdef CONFIG_X86
+	/* Use setter so that protections can be toggled if needed */
+	set_p4d(p4dp, p4d);
+#else
 	WRITE_ONCE(*p4dp, p4d);
+#endif
 	p4d_clear(p4dp);
 	p4d = READ_ONCE(*p4dp);
 	WARN_ON(!p4d_none(p4d));
@@ -549,7 +570,12 @@ static void __init pgd_clear_tests(struct mm_struct *mm, pgd_t *pgdp)
 
 	pr_debug("Validating PGD clear\n");
 	pgd = __pgd(pgd_val(pgd) | RANDOM_ORVALUE);
+#ifdef CONFIG_X86
+	/* Use setter so that protections can be toggled if needed */
+	set_pgd(pgdp, pgd);
+#else
 	WRITE_ONCE(*pgdp, pgd);
+#endif
 	pgd_clear(pgdp);
 	pgd = READ_ONCE(*pgdp);
 	WARN_ON(!pgd_none(pgd));
@@ -610,8 +636,12 @@ static void __init pmd_clear_tests(struct mm_struct *mm, pmd_t *pmdp)
 
 	pr_debug("Validating PMD clear\n");
 	pmd = __pmd(pmd_val(pmd) | RANDOM_ORVALUE);
-	WRITE_ONCE(*pmdp, pmd);
+#ifdef CONFIG_X86
+	/* Use setter so that protections can be toggled if needed */
 	pmd_clear(pmdp);
+#else
+	WRITE_ONCE(*pmdp, pmd);
+#endif
 	pmd = READ_ONCE(*pmdp);
 	WARN_ON(!pmd_none(pmd));
 }
-- 
2.17.1


  parent reply	other threads:[~2021-08-31  0:00 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-30 23:59 [RFC PATCH v2 00/19] PKS write protected page tables Rick Edgecombe
2021-08-30 23:59 ` [RFC PATCH v2 01/19] list: Support getting most recent element in list_lru Rick Edgecombe
2021-08-30 23:59 ` [RFC PATCH v2 02/19] list: Support list head not in object for list_lru Rick Edgecombe
2021-08-30 23:59 ` [RFC PATCH v2 03/19] x86/mm/cpa: Add grouped page allocations Rick Edgecombe
2021-08-30 23:59 ` [RFC PATCH v2 04/19] mm: Explicitly zero page table lock ptr Rick Edgecombe
2021-08-30 23:59 ` [RFC PATCH v2 05/19] x86, mm: Use cache of page tables Rick Edgecombe
2021-08-31  8:40   ` Mike Rapoport
2021-08-31 19:09     ` Edgecombe, Rick P
2021-08-30 23:59 ` [RFC PATCH v2 06/19] x86/mm/cpa: Add perm callbacks to grouped pages Rick Edgecombe
2021-08-30 23:59 ` [RFC PATCH v2 07/19] x86/cpufeatures: Add feature for pks tables Rick Edgecombe
2021-08-30 23:59 ` [RFC PATCH v2 08/19] x86/mm/cpa: Add get_grouped_page_atomic() Rick Edgecombe
2021-08-30 23:59 ` [RFC PATCH v2 09/19] x86/mm: Support GFP_ATOMIC in alloc_table_node() Rick Edgecombe
2021-08-31  8:32   ` Mike Rapoport
2021-08-30 23:59 ` [RFC PATCH v2 10/19] x86/mm: Use alloc_table() for fill_pte(), etc Rick Edgecombe
2021-08-31  8:47   ` Mike Rapoport
2021-08-31 18:48     ` Edgecombe, Rick P
2021-08-30 23:59 ` [RFC PATCH v2 11/19] mm/sparsemem: Use alloc_table() for table allocations Rick Edgecombe
2021-08-31  8:55   ` Mike Rapoport
2021-08-31 18:25     ` Edgecombe, Rick P
2021-09-01  7:22       ` Mike Rapoport
2021-09-02 13:56         ` Vlastimil Babka
2021-08-30 23:59 ` [RFC PATCH v2 12/19] x86/mm: Use free_table in unmap path Rick Edgecombe
2021-08-30 23:59 ` Rick Edgecombe [this message]
2021-08-30 23:59 ` [RFC PATCH v2 14/19] x86/efi: Toggle table protections when copying Rick Edgecombe
2021-08-30 23:59 ` [RFC PATCH v2 15/19] x86/mm/cpa: Add set_memory_pks() Rick Edgecombe
2021-08-30 23:59 ` [RFC PATCH v2 16/19] x86/mm: Protect page tables with PKS Rick Edgecombe
2021-08-31  8:56   ` Mike Rapoport
2021-08-31 17:55     ` Edgecombe, Rick P
2021-08-30 23:59 ` [RFC PATCH v2 17/19] x86/mm/cpa: PKS protect direct map page tables Rick Edgecombe
2021-08-31 10:14   ` Mike Rapoport
2021-08-31 17:58     ` Edgecombe, Rick P
2021-08-30 23:59 ` [RFC PATCH v2 18/19] x86/mm: Add PKS table soft mode Rick Edgecombe
2021-08-31  3:49   ` Randy Dunlap
2021-08-31 17:55     ` Edgecombe, Rick P
2021-08-30 23:59 ` [RFC PATCH v2 19/19] x86/mm: Add PKS table debug checking Rick Edgecombe

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