[RFC,v7,05/16] arm64/mm: Add support for XPFO
diff mbox series

Message ID 89f03091af87f5ab27bd6cafb032236d5bd81d65.1547153058.git.khalid.aziz@oracle.com
State New
Headers show
Series
  • Add support for eXclusive Page Frame Ownership
Related show

Commit Message

Khalid Aziz Jan. 10, 2019, 9:09 p.m. UTC
From: Juerg Haefliger <juerg.haefliger@canonical.com>

Enable support for eXclusive Page Frame Ownership (XPFO) for arm64 and
provide a hook for updating a single kernel page table entry (which is
required by the generic XPFO code).

v6: use flush_tlb_kernel_range() instead of __flush_tlb_one()

CC: linux-arm-kernel@lists.infradead.org
Signed-off-by: Juerg Haefliger <juerg.haefliger@canonical.com>
Signed-off-by: Tycho Andersen <tycho@docker.com>
Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com>
---
 arch/arm64/Kconfig     |  1 +
 arch/arm64/mm/Makefile |  2 ++
 arch/arm64/mm/xpfo.c   | 58 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 61 insertions(+)
 create mode 100644 arch/arm64/mm/xpfo.c

Comments

Konrad Rzeszutek Wilk Jan. 23, 2019, 2:20 p.m. UTC | #1
On Thu, Jan 10, 2019 at 02:09:37PM -0700, Khalid Aziz wrote:
> From: Juerg Haefliger <juerg.haefliger@canonical.com>
> 
> Enable support for eXclusive Page Frame Ownership (XPFO) for arm64 and
> provide a hook for updating a single kernel page table entry (which is
> required by the generic XPFO code).
> 
> v6: use flush_tlb_kernel_range() instead of __flush_tlb_one()
> 
> CC: linux-arm-kernel@lists.infradead.org
> Signed-off-by: Juerg Haefliger <juerg.haefliger@canonical.com>
> Signed-off-by: Tycho Andersen <tycho@docker.com>
> Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com>
> ---
>  arch/arm64/Kconfig     |  1 +
>  arch/arm64/mm/Makefile |  2 ++
>  arch/arm64/mm/xpfo.c   | 58 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 61 insertions(+)
>  create mode 100644 arch/arm64/mm/xpfo.c
> 
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index ea2ab0330e3a..f0a9c0007d23 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -171,6 +171,7 @@ config ARM64
>  	select SWIOTLB
>  	select SYSCTL_EXCEPTION_TRACE
>  	select THREAD_INFO_IN_TASK
> +	select ARCH_SUPPORTS_XPFO
>  	help
>  	  ARM 64-bit (AArch64) Linux support.
>  
> diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile
> index 849c1df3d214..cca3808d9776 100644
> --- a/arch/arm64/mm/Makefile
> +++ b/arch/arm64/mm/Makefile
> @@ -12,3 +12,5 @@ KASAN_SANITIZE_physaddr.o	+= n
>  
>  obj-$(CONFIG_KASAN)		+= kasan_init.o
>  KASAN_SANITIZE_kasan_init.o	:= n
> +
> +obj-$(CONFIG_XPFO)		+= xpfo.o
> diff --git a/arch/arm64/mm/xpfo.c b/arch/arm64/mm/xpfo.c
> new file mode 100644
> index 000000000000..678e2be848eb
> --- /dev/null
> +++ b/arch/arm64/mm/xpfo.c
> @@ -0,0 +1,58 @@
> +/*
> + * Copyright (C) 2017 Hewlett Packard Enterprise Development, L.P.
> + * Copyright (C) 2016 Brown University. All rights reserved.
> + *
> + * Authors:
> + *   Juerg Haefliger <juerg.haefliger@hpe.com>
> + *   Vasileios P. Kemerlis <vpk@cs.brown.edu>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2 as published by
> + * the Free Software Foundation.
> + */
> +
> +#include <linux/mm.h>
> +#include <linux/module.h>
> +
> +#include <asm/tlbflush.h>
> +
> +/*
> + * Lookup the page table entry for a virtual address and return a pointer to
> + * the entry. Based on x86 tree.
> + */
> +static pte_t *lookup_address(unsigned long addr)

The x86 also has level. Would it make sense to include that in here?
Konrad Rzeszutek Wilk Jan. 23, 2019, 2:24 p.m. UTC | #2
On Thu, Jan 10, 2019 at 02:09:37PM -0700, Khalid Aziz wrote:
> From: Juerg Haefliger <juerg.haefliger@canonical.com>
> 
> Enable support for eXclusive Page Frame Ownership (XPFO) for arm64 and
> provide a hook for updating a single kernel page table entry (which is
> required by the generic XPFO code).
> 
> v6: use flush_tlb_kernel_range() instead of __flush_tlb_one()
> 
> CC: linux-arm-kernel@lists.infradead.org
> Signed-off-by: Juerg Haefliger <juerg.haefliger@canonical.com>
> Signed-off-by: Tycho Andersen <tycho@docker.com>
> Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com>
> ---
>  arch/arm64/Kconfig     |  1 +
>  arch/arm64/mm/Makefile |  2 ++
>  arch/arm64/mm/xpfo.c   | 58 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 61 insertions(+)
>  create mode 100644 arch/arm64/mm/xpfo.c
> 
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index ea2ab0330e3a..f0a9c0007d23 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -171,6 +171,7 @@ config ARM64
>  	select SWIOTLB
>  	select SYSCTL_EXCEPTION_TRACE
>  	select THREAD_INFO_IN_TASK
> +	select ARCH_SUPPORTS_XPFO
>  	help
>  	  ARM 64-bit (AArch64) Linux support.
>  
> diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile
> index 849c1df3d214..cca3808d9776 100644
> --- a/arch/arm64/mm/Makefile
> +++ b/arch/arm64/mm/Makefile
> @@ -12,3 +12,5 @@ KASAN_SANITIZE_physaddr.o	+= n
>  
>  obj-$(CONFIG_KASAN)		+= kasan_init.o
>  KASAN_SANITIZE_kasan_init.o	:= n
> +
> +obj-$(CONFIG_XPFO)		+= xpfo.o
> diff --git a/arch/arm64/mm/xpfo.c b/arch/arm64/mm/xpfo.c
> new file mode 100644
> index 000000000000..678e2be848eb
> --- /dev/null
> +++ b/arch/arm64/mm/xpfo.c
> @@ -0,0 +1,58 @@
> +/*
> + * Copyright (C) 2017 Hewlett Packard Enterprise Development, L.P.
> + * Copyright (C) 2016 Brown University. All rights reserved.
> + *
> + * Authors:
> + *   Juerg Haefliger <juerg.haefliger@hpe.com>
> + *   Vasileios P. Kemerlis <vpk@cs.brown.edu>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2 as published by
> + * the Free Software Foundation.
> + */
> +
> +#include <linux/mm.h>
> +#include <linux/module.h>
> +
> +#include <asm/tlbflush.h>
> +
> +/*
> + * Lookup the page table entry for a virtual address and return a pointer to
> + * the entry. Based on x86 tree.
> + */
> +static pte_t *lookup_address(unsigned long addr)
> +{
> +	pgd_t *pgd;
> +	pud_t *pud;
> +	pmd_t *pmd;
> +
> +	pgd = pgd_offset_k(addr);
> +	if (pgd_none(*pgd))
> +		return NULL;
> +
> +	pud = pud_offset(pgd, addr);
> +	if (pud_none(*pud))
> +		return NULL;
> +
> +	pmd = pmd_offset(pud, addr);
> +	if (pmd_none(*pmd))
> +		return NULL;
> +
> +	return pte_offset_kernel(pmd, addr);
> +}
> +
> +/* Update a single kernel page table entry */
> +inline void set_kpte(void *kaddr, struct page *page, pgprot_t prot)
> +{
> +	pte_t *pte = lookup_address((unsigned long)kaddr);
> +
> +	set_pte(pte, pfn_pte(page_to_pfn(page), prot));

Thought on the other hand.. what if the page is PMD? Do you really want
to do this?

What if 'pte' is NULL?
> +}
> +
> +inline void xpfo_flush_kernel_tlb(struct page *page, int order)
> +{
> +	unsigned long kaddr = (unsigned long)page_address(page);
> +	unsigned long size = PAGE_SIZE;
> +
> +	flush_tlb_kernel_range(kaddr, kaddr + (1 << order) * size);

Ditto here. You are assuming it is PTE, but it may be PMD or such.
Or worts - the lookup_address could be NULL.

> +}
> -- 
> 2.17.1
>

Patch
diff mbox series

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index ea2ab0330e3a..f0a9c0007d23 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -171,6 +171,7 @@  config ARM64
 	select SWIOTLB
 	select SYSCTL_EXCEPTION_TRACE
 	select THREAD_INFO_IN_TASK
+	select ARCH_SUPPORTS_XPFO
 	help
 	  ARM 64-bit (AArch64) Linux support.
 
diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile
index 849c1df3d214..cca3808d9776 100644
--- a/arch/arm64/mm/Makefile
+++ b/arch/arm64/mm/Makefile
@@ -12,3 +12,5 @@  KASAN_SANITIZE_physaddr.o	+= n
 
 obj-$(CONFIG_KASAN)		+= kasan_init.o
 KASAN_SANITIZE_kasan_init.o	:= n
+
+obj-$(CONFIG_XPFO)		+= xpfo.o
diff --git a/arch/arm64/mm/xpfo.c b/arch/arm64/mm/xpfo.c
new file mode 100644
index 000000000000..678e2be848eb
--- /dev/null
+++ b/arch/arm64/mm/xpfo.c
@@ -0,0 +1,58 @@ 
+/*
+ * Copyright (C) 2017 Hewlett Packard Enterprise Development, L.P.
+ * Copyright (C) 2016 Brown University. All rights reserved.
+ *
+ * Authors:
+ *   Juerg Haefliger <juerg.haefliger@hpe.com>
+ *   Vasileios P. Kemerlis <vpk@cs.brown.edu>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/mm.h>
+#include <linux/module.h>
+
+#include <asm/tlbflush.h>
+
+/*
+ * Lookup the page table entry for a virtual address and return a pointer to
+ * the entry. Based on x86 tree.
+ */
+static pte_t *lookup_address(unsigned long addr)
+{
+	pgd_t *pgd;
+	pud_t *pud;
+	pmd_t *pmd;
+
+	pgd = pgd_offset_k(addr);
+	if (pgd_none(*pgd))
+		return NULL;
+
+	pud = pud_offset(pgd, addr);
+	if (pud_none(*pud))
+		return NULL;
+
+	pmd = pmd_offset(pud, addr);
+	if (pmd_none(*pmd))
+		return NULL;
+
+	return pte_offset_kernel(pmd, addr);
+}
+
+/* Update a single kernel page table entry */
+inline void set_kpte(void *kaddr, struct page *page, pgprot_t prot)
+{
+	pte_t *pte = lookup_address((unsigned long)kaddr);
+
+	set_pte(pte, pfn_pte(page_to_pfn(page), prot));
+}
+
+inline void xpfo_flush_kernel_tlb(struct page *page, int order)
+{
+	unsigned long kaddr = (unsigned long)page_address(page);
+	unsigned long size = PAGE_SIZE;
+
+	flush_tlb_kernel_range(kaddr, kaddr + (1 << order) * size);
+}