From: Julien Grall <julien.grall@arm.com>
To: xen-devel@lists.xen.org
Cc: andre.przywara@arm.com, Julien Grall <julien.grall@arm.com>,
sstabellini@kernel.org
Subject: [PATCH v3 7/9] xen/arm: mm: Embed permission in the flags
Date: Mon, 2 Oct 2017 18:31:48 +0100 [thread overview]
Message-ID: <20171002173150.5404-8-julien.grall@arm.com> (raw)
In-Reply-To: <20171002173150.5404-1-julien.grall@arm.com>
Currently, it is not possible to specify the permission of a new
mapping. It would be necessary to use the function modify_xen_mappings
with a different set of flags.
Introduce a couple of new flags for the permissions (Non-eXecutable,
Read-Only) and also provides definition that combine the memory attribute
and permission for common combinations.
PAGE_HYPERVISOR is now an alias to PAGE_HYPERVISOR_RW (read-write,
non-executable mappings). This does not affect the current mapping using
PAGE_HYPERVISOR because Xen is currently forcing all the mapping to be
non-executable by default (see mfn_to_xen_entry).
A follow-up patch will change modify_xen_mappings to use the new flags.
Signed-off-by: Julien Grall <julien.grall@arm.com>
---
Changes in v3:
- Add a comment about _PAGE_DEVICE and _PAGE_NORMAL
Changes in v2:
- Update the commit message
---
xen/include/asm-arm/page.h | 25 ++++++++++++++++++++++---
1 file changed, 22 insertions(+), 3 deletions(-)
diff --git a/xen/include/asm-arm/page.h b/xen/include/asm-arm/page.h
index aa3e83f5b4..e2b3e402d0 100644
--- a/xen/include/asm-arm/page.h
+++ b/xen/include/asm-arm/page.h
@@ -69,12 +69,31 @@
* Layout of the flags used for updating the hypervisor page tables
*
* [0:2] Memory Attribute Index
+ * [3:4] Permission flags
*/
#define PAGE_AI_MASK(x) ((x) & 0x7U)
-#define PAGE_HYPERVISOR (MT_NORMAL)
-#define PAGE_HYPERVISOR_NOCACHE (MT_DEVICE_nGnRE)
-#define PAGE_HYPERVISOR_WC (MT_NORMAL_NC)
+#define _PAGE_XN_BIT 3
+#define _PAGE_RO_BIT 4
+#define _PAGE_XN (1U << _PAGE_XN_BIT)
+#define _PAGE_RO (1U << _PAGE_RO_BIT)
+#define PAGE_XN_MASK(x) (((x) >> _PAGE_XN_BIT) & 0x1U)
+#define PAGE_RO_MASK(x) (((x) >> _PAGE_RO_BIT) & 0x1U)
+
+/*
+ * _PAGE_DEVICE and _PAGE_NORMAL are conveniences defines. They are not
+ * meant to be used outside of the headers.
+ */
+#define _PAGE_DEVICE _PAGE_XN
+#define _PAGE_NORMAL MT_NORMAL
+
+#define PAGE_HYPERVISOR_RO (_PAGE_NORMAL|_PAGE_RO|_PAGE_XN)
+#define PAGE_HYPERVISOR_RX (_PAGE_NORMAL|_PAGE_RO)
+#define PAGE_HYPERVISOR_RW (_PAGE_NORMAL|_PAGE_XN)
+
+#define PAGE_HYPERVISOR PAGE_HYPERVISOR_RW
+#define PAGE_HYPERVISOR_NOCACHE (_PAGE_DEVICE|MT_DEVICE_nGnRE)
+#define PAGE_HYPERVISOR_WC (_PAGE_DEVICE|MT_NORMAL_NC)
/*
* Defines for changing the hypervisor PTE .ro and .nx bits. This is only to be
--
2.11.0
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next prev parent reply other threads:[~2017-10-02 17:31 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-02 17:31 [PATCH v3 0/9] xen/arm: Memory subsystem clean-up Julien Grall
2017-10-02 17:31 ` [PATCH v3 1/9] xen/arm: page: Use ARMv8 naming to improve readability Julien Grall
2017-10-02 17:31 ` [PATCH v3 2/9] xen/arm: page: Clean-up the definition of MAIRVAL Julien Grall
2017-10-02 17:31 ` [PATCH v3 3/9] xen/arm: mm: Rename and clarify AP[1] in the stage-1 page table Julien Grall
2017-10-02 17:31 ` [PATCH v3 4/9] xen/arm: Switch to SYS_STATE_boot just after end_boot_allocator() Julien Grall
2017-10-02 17:31 ` [PATCH v3 5/9] xen/arm: mm: Rename 'ai' into 'flags' in create_xen_entries Julien Grall
2017-10-02 17:31 ` [PATCH v3 6/9] xen/arm: page: Describe the layout of flags used to update page tables Julien Grall
2017-10-02 17:31 ` Julien Grall [this message]
2017-10-09 12:34 ` [PATCH v3 7/9] xen/arm: mm: Embed permission in the flags Julien Grall
2017-10-02 17:31 ` [PATCH v3 8/9] xen/arm: mm: Handle permission flags when adding a new mapping Julien Grall
2017-10-02 17:31 ` [PATCH v3 9/9] xen/arm: mm: Use memory flags for modify_xen_mappings rather than custom one Julien Grall
2017-10-02 18:14 ` Konrad Rzeszutek Wilk
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