All of lore.kernel.org
 help / color / mirror / Atom feed
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: linux-mm@kvack.org, akpm@linux-foundation.org
Cc: mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Subject: [PATCH 01/16] powerpc/mm: Add DEBUG_VM WARN for pmd_clear
Date: Wed, 12 Aug 2020 12:03:43 +0530	[thread overview]
Message-ID: <20200812063358.369514-1-aneesh.kumar@linux.ibm.com> (raw)

With the hash page table, the kernel should not use pmd_clear for clearing
huge pte entries. Add a DEBUG_VM WARN to catch the wrong usage.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
 arch/powerpc/include/asm/book3s/64/pgtable.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 6de56c3b33c4..079211968987 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -868,6 +868,13 @@ static inline bool pte_ci(pte_t pte)
 
 static inline void pmd_clear(pmd_t *pmdp)
 {
+	if (IS_ENABLED(CONFIG_DEBUG_VM) && !radix_enabled()) {
+		/*
+		 * Don't use this if we can possibly have a hash page table
+		 * entry mapping this.
+		 */
+		WARN_ON((pmd_val(*pmdp) & (H_PAGE_HASHPTE | _PAGE_PTE)) == (H_PAGE_HASHPTE | _PAGE_PTE));
+	}
 	*pmdp = __pmd(0);
 }
 
@@ -916,6 +923,13 @@ static inline int pmd_bad(pmd_t pmd)
 
 static inline void pud_clear(pud_t *pudp)
 {
+	if (IS_ENABLED(CONFIG_DEBUG_VM) && !radix_enabled()) {
+		/*
+		 * Don't use this if we can possibly have a hash page table
+		 * entry mapping this.
+		 */
+		WARN_ON((pud_val(*pudp) & (H_PAGE_HASHPTE | _PAGE_PTE)) == (H_PAGE_HASHPTE | _PAGE_PTE));
+	}
 	*pudp = __pud(0);
 }
 
-- 
2.26.2



WARNING: multiple messages have this Message-ID (diff)
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: linux-mm@kvack.org, akpm@linux-foundation.org
Cc: linuxppc-dev@lists.ozlabs.org,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
	Anshuman Khandual <anshuman.khandual@arm.com>
Subject: [PATCH 01/16] powerpc/mm: Add DEBUG_VM WARN for pmd_clear
Date: Wed, 12 Aug 2020 12:03:43 +0530	[thread overview]
Message-ID: <20200812063358.369514-1-aneesh.kumar@linux.ibm.com> (raw)

With the hash page table, the kernel should not use pmd_clear for clearing
huge pte entries. Add a DEBUG_VM WARN to catch the wrong usage.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
 arch/powerpc/include/asm/book3s/64/pgtable.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 6de56c3b33c4..079211968987 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -868,6 +868,13 @@ static inline bool pte_ci(pte_t pte)
 
 static inline void pmd_clear(pmd_t *pmdp)
 {
+	if (IS_ENABLED(CONFIG_DEBUG_VM) && !radix_enabled()) {
+		/*
+		 * Don't use this if we can possibly have a hash page table
+		 * entry mapping this.
+		 */
+		WARN_ON((pmd_val(*pmdp) & (H_PAGE_HASHPTE | _PAGE_PTE)) == (H_PAGE_HASHPTE | _PAGE_PTE));
+	}
 	*pmdp = __pmd(0);
 }
 
@@ -916,6 +923,13 @@ static inline int pmd_bad(pmd_t pmd)
 
 static inline void pud_clear(pud_t *pudp)
 {
+	if (IS_ENABLED(CONFIG_DEBUG_VM) && !radix_enabled()) {
+		/*
+		 * Don't use this if we can possibly have a hash page table
+		 * entry mapping this.
+		 */
+		WARN_ON((pud_val(*pudp) & (H_PAGE_HASHPTE | _PAGE_PTE)) == (H_PAGE_HASHPTE | _PAGE_PTE));
+	}
 	*pudp = __pud(0);
 }
 
-- 
2.26.2


             reply	other threads:[~2020-08-12  6:34 UTC|newest]

Thread overview: 84+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-12  6:33 Aneesh Kumar K.V [this message]
2020-08-12  6:33 ` [PATCH 01/16] powerpc/mm: Add DEBUG_VM WARN for pmd_clear Aneesh Kumar K.V
2020-08-12  6:33 ` [PATCH 02/16] debug_vm_pgtable/ppc64: Avoid setting top bits in radom value Aneesh Kumar K.V
2020-08-12  6:33   ` Aneesh Kumar K.V
2020-08-12  6:40   ` Christophe Leroy
2020-08-12  6:43     ` Aneesh Kumar K.V
2020-08-12  8:12   ` Anshuman Khandual
2020-08-12  8:12     ` Anshuman Khandual
2020-08-12  8:25     ` Aneesh Kumar K.V
2020-08-12  8:25       ` Aneesh Kumar K.V
2020-08-12  6:33 ` [PATCH 03/16] debug_vm_pgtable/set_pte: Don't use set_pte_at to update an existing pte entry Aneesh Kumar K.V
2020-08-12  6:33   ` Aneesh Kumar K.V
2020-08-12  9:12   ` Anshuman Khandual
2020-08-12  9:12     ` Anshuman Khandual
2020-08-12  9:22     ` Aneesh Kumar K.V
2020-08-12  9:22       ` Aneesh Kumar K.V
2020-08-12  6:33 ` [PATCH 04/16] debug_vm_pgtables/hugevmap: Use the arch helper to identify huge vmap support Aneesh Kumar K.V
2020-08-12  6:33   ` Aneesh Kumar K.V
2020-08-12 10:30   ` Anshuman Khandual
2020-08-12 10:30     ` Anshuman Khandual
2020-08-12  6:33 ` [PATCH 05/16] debug_vm_pgtable/savedwrite: Enable savedwrite test with CONFIG_NUMA_BALANCING Aneesh Kumar K.V
2020-08-12  6:33   ` Aneesh Kumar K.V
2020-08-12 11:24   ` Anshuman Khandual
2020-08-12 11:24     ` Anshuman Khandual
2020-08-12  6:33 ` [PATCH 06/16] debug_vm_pgtable/THP: Mark the pte entry huge before using set_pmd_at Aneesh Kumar K.V
2020-08-12  6:33   ` Aneesh Kumar K.V
2020-08-12  6:33 ` [PATCH 07/16] debug_vm_pgtable/THP: Mark the pte entry huge before using set_pud_at Aneesh Kumar K.V
2020-08-12  6:33   ` Aneesh Kumar K.V
2020-08-12 11:49   ` Anshuman Khandual
2020-08-12 11:49     ` Anshuman Khandual
2020-08-12  6:33 ` [PATCH 08/16] debug_vm_pgtable/set_pmd: Don't use set_pmd_at to update an existing pmd entry Aneesh Kumar K.V
2020-08-12  6:33   ` Aneesh Kumar K.V
2020-08-12 12:46   ` Anshuman Khandual
2020-08-12 12:46     ` Anshuman Khandual
2020-08-12  6:33 ` [PATCH 09/16] debug_vm_pgtable/set_pud: Don't use set_pud_at to update an existing pud entry Aneesh Kumar K.V
2020-08-12  6:33   ` Aneesh Kumar K.V
2020-08-12 12:46   ` Anshuman Khandual
2020-08-12 12:46     ` Anshuman Khandual
2020-08-12  6:33 ` [PATCH 10/16] debug_vm_pgtable/thp: Use page table depost/withdraw with THP Aneesh Kumar K.V
2020-08-12  6:33   ` Aneesh Kumar K.V
2020-08-13  5:25   ` Anshuman Khandual
2020-08-13  5:25     ` Anshuman Khandual
2020-08-13  6:38     ` Aneesh Kumar K.V
2020-08-13  6:38       ` Aneesh Kumar K.V
2020-08-12  6:33 ` [PATCH 11/16] debug_vm_pgtable/locks: Move non page table modifying test together Aneesh Kumar K.V
2020-08-12  6:33   ` Aneesh Kumar K.V
2020-08-12  6:33 ` [PATCH 12/16] debug_vm_pgtable/locks: Take correct page table lock Aneesh Kumar K.V
2020-08-12  6:33   ` Aneesh Kumar K.V
2020-08-12  6:33 ` [PATCH 13/16] debug_vm_pgtable/pmd_clear: Don't use pmd/pud_clear on pte entries Aneesh Kumar K.V
2020-08-12  6:33   ` Aneesh Kumar K.V
2020-08-13  5:27   ` Anshuman Khandual
2020-08-13  5:27     ` Anshuman Khandual
2020-08-13  8:45     ` Aneesh Kumar K.V
2020-08-13  8:45       ` Aneesh Kumar K.V
2020-08-12  6:33 ` [PATCH 14/16] debug_vm_pgtable/hugetlb: Disable hugetlb test on ppc64 Aneesh Kumar K.V
2020-08-12  6:33   ` Aneesh Kumar K.V
2020-08-12 13:03   ` Anshuman Khandual
2020-08-12 13:03     ` Anshuman Khandual
2020-08-12 13:16     ` Aneesh Kumar K.V
2020-08-12 13:16       ` Aneesh Kumar K.V
2020-08-12 13:34       ` Anshuman Khandual
2020-08-12 13:34         ` Anshuman Khandual
2020-08-12 13:52         ` Aneesh Kumar K.V
2020-08-12 13:52           ` Aneesh Kumar K.V
2020-08-14  8:43           ` Anshuman Khandual
2020-08-14  8:43             ` Anshuman Khandual
2020-08-19  6:54             ` Aneesh Kumar K.V
2020-08-19  6:54               ` Aneesh Kumar K.V
2020-08-12  6:33 ` [PATCH 15/16] debug_vm_pgtable/savedwrite: Use savedwrite test with protnone ptes Aneesh Kumar K.V
2020-08-12  6:33   ` Aneesh Kumar K.V
2020-08-12 13:06   ` Anshuman Khandual
2020-08-12 13:06     ` Anshuman Khandual
2020-08-12  6:33 ` [PATCH 16/16] debug_vm_pgtable/ppc64: Add a variant of pfn_pte/pmd Aneesh Kumar K.V
2020-08-12  6:33   ` Aneesh Kumar K.V
2020-08-13  5:30   ` Anshuman Khandual
2020-08-13  5:30     ` Anshuman Khandual
2020-08-13  6:37     ` Aneesh Kumar K.V
2020-08-13  6:37       ` Aneesh Kumar K.V
2020-08-14  8:29       ` Anshuman Khandual
2020-08-14  8:29         ` Anshuman Khandual
2020-08-12  7:46 ` [PATCH 01/16] powerpc/mm: Add DEBUG_VM WARN for pmd_clear Anshuman Khandual
2020-08-12  7:46   ` Anshuman Khandual
2020-08-12  8:27   ` Aneesh Kumar K.V
2020-08-12  8:27     ` Aneesh Kumar K.V

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200812063358.369514-1-aneesh.kumar@linux.ibm.com \
    --to=aneesh.kumar@linux.ibm.com \
    --cc=akpm@linux-foundation.org \
    --cc=anshuman.khandual@arm.com \
    --cc=linux-mm@kvack.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=mpe@ellerman.id.au \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.